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  • Image-guided laser ablation in the treatment of recurrence of renal tumours: technique and preliminary results
    Eur. Radiol. Exp. (IF 0) Pub Date : 2020-01-03
    Federica Ferrari, Giovanni Mauri, Luca Nicosia, Gianluca Maria Varano, Guido Bonomo, Franco Orsi

    Abstract Abdominal recurrences of renal cell carcinoma (RCC) after surgery might represent a challenge for treatment, often requiring difficult surgeries or anticipated systemic therapy. Our aim is to illustrate a novel application of laser ablation for the treatment of abdominal recurrences of RCC. Patients with abdominal recurrences of renal cancer were treated under ultrasound/computed tomography guidance with a diode laser inserted into the lesion through a thin 21-G needle. A fixed 3-W power protocol was used, changing the illumination time according to lesion dimension and shape. Also, technical success, technical efficacy, local tumour progression, and major and minor complications were retrospectively analysed. Three patients were treated with image-guided laser ablation for abdominal recurrences of RCC. In all cases, it was possible to perform ablation as preoperatively planned and all three nodules (size of 6, 8, and 12 mm) were completely ablated with no evidence of residual enhancement after 6 weeks at contrast-enhanced CT. No minor or major complications were observed. No local tumour progression was reported up to 12 months from ablation. Image-guided laser ablation holds the potential to offer a minimally invasive treatment to patients with abdominal recurrence of RCC. Further studies are needed to evaluate the clinical role of this technique.

  • Imaging of tumour response to immunotherapy
    Eur. Radiol. Exp. (IF 0) Pub Date : 2020-01-03
    Clarisse Dromain, Catherine Beigelman, Chiara Pozzessere, Rafael Duran, Antonia Digklia

    Abstract A wide range of cancer immunotherapy approaches has been developed including non-specific immune-stimulants such as cytokines, cancer vaccines, immune checkpoint inhibitors (ICIs), and adoptive T cell therapy. Among them, ICIs are the most commonly used and intensively studied. Since 2011, these drugs have received marketing authorisation for melanoma, lung, bladder, renal, and head and neck cancers, with remarkable and long-lasting treatment response in some patients. The novel mechanism of action of ICIs, with immune and T cell activation, leads to unusual patterns of response on imaging, with the advent of so-called pseudoprogression being more pronounced and frequently observed when compared to other anticancer therapies. Pseudoprogression, described in about 2–10% of patients treated with ICIs, corresponds to an increase of tumour burden and/or the appearance of new lesions due to infiltration by activated T cells before the disease responds to therapy. To overcome the limitation of response evaluation criteria in solid tumors (RECIST) to assess these specific changes, new imaging criteria—so-called immune-related response criteria and then immune-related RECIST (irRECIST)—were proposed. The major modification involved the inclusion of the measurements of new target lesions into disease assessments and the need for a 4-week re-assessment to confirm or not confirm progression. The RECIST working group introduced the new concept of “unconfirmed progression”, into the irRECIST. This paper reviews current immunotherapeutic approaches and summarises radiologic criteria to evaluate new patterns of response to immunotherapy. Furthermore, imaging features of immunotherapy-related adverse events and available predictive biomarkers of response are presented.

  • HCC screening: assessment of an abbreviated non-contrast MRI protocol
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-12-18
    Michael Vinchill Chan, Stephen J. McDonald, Yang-Yi Ong, Katerina Mastrocostas, Edwin Ho, Ya Ruth Huo, Cositha Santhakumar, Alice Unah Lee, Jessica Yang

    Hepatocellular carcinoma (HCC) guidelines recommend ultrasound screening in high-risk patients. However, in some patients, ultrasound image quality is suboptimal due to factors such as hepatic steatosis, cirrhosis, and confounding lesions. Our aim was to investigate an abbreviated non-contrast magnetic resonance imaging (aNC-MRI) protocol as a potential alternative screening method.

  • Multiparametric quantitative and texture 18 F-FDG PET/CT analysis for primary malignant tumour grade differentiation
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-12-18
    Mykola Novikov

    18F-FDG positron emission tomography/computed tomography (PET/CT) is a successfully used imaging modality in oncology. The aim of the study was to investigate a connection of epithelial tumour differentiation grade with both semiquantitative and quantitative metabolic PET data focusing on creation of multiparametric model of tumour grade prediction utilising both standardised uptake value-based and texture-based 18F-FDG PET parameters and to investigate an influence of different image segmentation techniques on these parameters and modelling.

  • Prospective study to assess the tissue response to HPC-coated p48 flow diverter stents compared to uncoated devices in the rabbit carotid artery model
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-12-05
    Tim Lenz-Habijan, Pervinder Bhogal, Catrin Bannewitz, Ralf Hannes, Hermann Monstadt, Andreas Simgen, Ruben Mühl-Benninghaus, Wolfgang Reith, Hans Henkes

    Flow diverters (FDs) are widely used in the treatment of intracranial aneurysms, but the required medication increases the risk of haemorrhagic complications and limits their use in the acute setting. Surface modified FDs may limit the need for dual antiplatelet therapy (DAPT). Hydrophilic polymer coating (HPC) may reduce the need of medication.

  • Optimising dual-energy CT scan parameters for virtual non-calcium imaging of the bone marrow: a phantom study
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-12-04
    Felix C. Müller, Henrik Børgesen, Kasper Gosvig, Anders Rodell, Christian Booz, Bernhard Schmidt, Bernhard Krauss, Mikael Boesen

    We investigated the influence of dose, spectral separation, pitch, rotation time, and reconstruction kernel on accuracy and image noise of virtual non-calcium images using a bone marrow phantom.

  • Associations of thigh muscle fat infiltration with isometric strength measurements based on chemical shift encoding-based water-fat magnetic resonance imaging
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-11-20
    Stephanie Inhuber, Nico Sollmann, Sarah Schlaeger, Michael Dieckmeyer, Egon Burian, Caroline Kohlmeyer, Dimitrios C. Karampinos, Jan S. Kirschke, Thomas Baum, Florian Kreuzpointner, Ansgar Schwirtz

    Assessment of the thigh muscle fat composition using magnetic resonance imaging (MRI) can provide surrogate markers in subjects suffering from various musculoskeletal disorders including knee osteoarthritis or neuromuscular diseases. However, little is known about the relationship with muscle strength. Therefore, we investigated the associations of thigh muscle fat with isometric strength measurements.

  • Diagnostic performance of machine learning applied to texture analysis-derived features for breast lesion characterisation at automated breast ultrasound: a pilot study
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-11-01
    Magda Marcon, Alexander Ciritsis, Cristina Rossi, Anton S. Becker, Nicole Berger, Moritz C. Wurnig, Matthias W. Wagner, Thomas Frauenfelder, Andreas Boss

    Our aims were to determine if features derived from texture analysis (TA) can distinguish normal, benign, and malignant tissue on automated breast ultrasound (ABUS); to evaluate whether machine learning (ML) applied to TA can categorise ABUS findings; and to compare ML to the analysis of single texture features for lesion classification.

  • Reproducibility of semiautomated body composition segmentation of abdominal computed tomography: a multiobserver study
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-10-30
    Lisa Jannicke Kjønigsen, Magnus Harneshaug, Ann-Monica Fløtten, Lena Korsmo Karterud, Kent Petterson, Grethe Skjolde, Heidi B. Eggesbø, Harald Weedon-Fekjær, Hege Berg Henriksen, Peter M. Lauritzen

    Segmentation of computed tomography (CT) images provides quantitative data on body tissue composition, which may greatly impact the development and progression of diseases such as type 2 diabetes mellitus and cancer. We aimed to evaluate the inter- and intraobserver variation of semiautomated segmentation, to assess whether multiple observers may interchangeably perform this task.

  • Fully automated convolutional neural network-based affine algorithm improves liver registration and lesion co-localization on hepatobiliary phase T1-weighted MR images
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-10-26
    Kyle A. Hasenstab, Guilherme Moura Cunha, Atsushi Higaki, Shintaro Ichikawa, Kang Wang, Timo Delgado, Ryan L. Brunsing, Alexandra Schlein, Leornado Kayat Bittencourt, Armin Schwartzman, Katie J. Fowler, Albert Hsiao, Claude B. Sirlin

    Liver alignment between series/exams is challenged by dynamic morphology or variability in patient positioning or motion. Image registration can improve image interpretation and lesion co-localization. We assessed the performance of a convolutional neural network algorithm to register cross-sectional liver imaging series and compared its performance to manual image registration.

  • An isolated beating pig heart platform for a comprehensive evaluation of intracardiac blood flow with 4D flow MRI: a feasibility study
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-10-25
    Eva S. Peper, Alberto M. Leopaldi, Sjoerd van Tuijl, Bram F. Coolen, Gustav J. Strijkers, Jan Baan, R. Nils Planken, Arend de Weger, Aart J. Nederveen, Henk A. Marquering, Pim van Ooij

    Cardiac magnetic resonance imaging (MRI) in large animals is cumbersome for various reasons, including ethical considerations, costs of housing and maintenance, and need for anaesthesia. Our primary purpose was to show the feasibility of an isolated beating pig heart model for four-dimensional (4D) flow MRI for investigating intracardiac blood flow patterns and flow parameters using slaughterhouse side products. In addition, the feasibility of evaluating transcatheter aortic valve replacement (TAVR) in the model was investigated.

  • A machine learning model for the prediction of survival and tumor subtype in pancreatic ductal adenocarcinoma from preoperative diffusion-weighted imaging
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-10-17
    Georgios Kaissis, Sebastian Ziegelmayer, Fabian Lohöfer, Hana Algül, Matthias Eiber, Wilko Weichert, Roland Schmid, Helmut Friess, Ernst Rummeny, Donna Ankerst, Jens Siveke, Rickmer Braren

    To develop a supervised machine learning (ML) algorithm predicting above- versus below-median overall survival (OS) from diffusion-weighted imaging-derived radiomic features in patients with pancreatic ductal adenocarcinoma (PDAC).

  • Reduction of radiation exposure to operating physician and assistant using a real-time auditory feedback dosimeter during femoral artery puncturing: a study on swine model
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-09-23
    Muhammad Umair Ahmad Khan, Byung-Ju Yi

    Real-time dosimeters may create a relatively safer environment not only for the patient but also for the physician and the assistant as well. We propose the use of a real-time radiation measurement dosimeter having auditory feedback to reduce radiation exposure.

  • Artefact and ablation performance of an MR-conditional high-power microwave system in bovine livers: an ex vivo study
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-09-23
    Antonia Grimm, Moritz Winkelmann, Jakob Weiß, Georg Gohla, Gunnar Blumenstock, Konstantin Nikolaou, Stephan Clasen, Rüdiger Hoffmann

    We evaluated a magnetic resonance (MR)-conditional high-power microwave ablation system.

  • Deep learning to convert unstructured CT pulmonary angiography reports into structured reports
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-09-23
    Adam Spandorfer, Cody Branch, Puneet Sharma, Pooyan Sahbaee, U. Joseph Schoepf, James G. Ravenel, John W. Nance

    Structured reports have been shown to improve communication between radiologists and providers. However, some radiologists are concerned about resultant decreased workflow efficiency. We tested a machine learning-based algorithm designed to convert unstructured computed tomography pulmonary angiography (CTPA) reports into structured reports.

  • In vitro qualitative and quantitative CT assessment of iodinated aerosol nasal deposition using a 3D-printed nasal replica
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-08-21
    Thomas Sartoretti, Manoj Mannil, Stefan Biendl, Johannes M. Froehlich, Hatem Alkadhi, Matthias Zadory

    Computed tomography can provide high-resolution details on nasal anatomy being potentially useful for the assessment of nasal spray deposition. The purpose of this technical note was to present a method based on CT imaging to assess qualitatively and quantitatively the in vitro spray deposition patterns within the sinonasal cavities of a nasal replica obtained by three-dimensional (3D) printing, using iodinated contrast agent labelled solutions with high spatial and temporal resolution. Using a third generation dual-source CT scanner in single energy mode, scans of a nasal replica were acquired following application of iodinated contrast agent labelled aerosols with an iodine concentration of 92.5 mgl/mL. Two software programmes were then utilised (Osirix MD v.9.0, Pixmeo, Geneva, Switzerland; 3mensio, Pie Medical Imaging, Bilthoven, Netherlands) to generate three-dimensional reconstructions of the scans, thus enabling the rapid detection and visualisation of administered single droplets and their voxel-by-voxel localisation. Using this approach, we achieved recovery rates between 84–98% and 89–109% (depending on the software programme) of the total applied aerosol volume.

  • Breast cancer Ki-67 expression prediction by digital breast tomosynthesis radiomics features
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-08-14
    Alberto Stefano Tagliafico, Bianca Bignotti, Federica Rossi, Joao Matos, Massimo Calabrese, Francesca Valdora, Nehmat Houssami

    To investigate whether quantitative radiomic features extracted from digital breast tomosynthesis (DBT) are associated with Ki-67 expression of breast cancer.

  • Bone strain index reproducibility and soft tissue thickness influence: a dual x-ray photon absorptiometry phantom study
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-08-14
    C. Messina, L. P. Piodi, L. Rinaudo, I. Emili, F. Porro, C. Buonomenna, L. M. Sconfienza, L. Vergani, F. M. Ulivieri

    Bone strain index (BSI) is a tool measuring bone strain, derived from dual x-ray photon absorptiometry. It is able to characterise an aspect of bone quality that, joined to the quantity and quality parameters of bone mineral density (BMD) and trabecular bone score (TBS), permits an accurate definition of fracture risk. As no data are available about BSI precision, our aim was to assess its in vitro reproducibility.

  • Two-centre comparative experimental study of biparametric MRI at 3.0 T with and without endorectal coil using kiwifruit ( Actinidia deliciosa ) as a phantom for human prostate
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-08-14
    Sophie Murer, Juergen Scheidler, Ulrike L. Mueller-Lisse, Marissa Helling, Michael Scherr, Ullrich G. Mueller-Lisse

    Application of an endorectal coil (ERC) for 3.0-T prostate magnetic resonance imaging (MRI) is contentious. We hypothesised that a multicoil phased-array protocol provides T2-weighted images (T2WI) and diffusion-weighted images (DWI) with reduced field-of-view (DWIreduced) and monoexponential apparent diffusion coefficient (ADC) maps that are technically equivalent with ERC or without ERC (noERC).

  • Machine learning applications in prostate cancer magnetic resonance imaging
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-08-07
    Renato Cuocolo, Maria Brunella Cipullo, Arnaldo Stanzione, Lorenzo Ugga, Valeria Romeo, Leonardo Radice, Arturo Brunetti, Massimo Imbriaco

    With this review, we aimed to provide a synopsis of recently proposed applications of machine learning (ML) in radiology focusing on prostate magnetic resonance imaging (MRI). After defining the difference between ML and classical rule-based algorithms and the distinction among supervised, unsupervised and reinforcement learning, we explain the characteristic of deep learning (DL), a particular new type of ML, including its structure mimicking human neural networks and its ‘black box’ nature. Differences in the pipeline for applying ML and DL to prostate MRI are highlighted. The following potential clinical applications in different settings are outlined, many of them based only on MRI-unenhanced sequences: gland segmentation; assessment of lesion aggressiveness to distinguish between clinically significant and indolent cancers, allowing for active surveillance; cancer detection/diagnosis and localisation (transition versus peripheral zone, use of prostate imaging reporting and data system (PI-RADS) version 2), reading reproducibility, differentiation of cancers from prostatitis benign hyperplasia; local staging and pre-treatment assessment (detection of extraprostatic disease extension, planning of radiation therapy); and prediction of biochemical recurrence. Results are promising, but clinical applicability still requires more robust validation across scanner vendors, field strengths and institutions.

  • Nipple-sparing mastectomy: external validation of a three-dimensional automated method to predict nipple occult tumour involvement on preoperative breast MRI
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-08-07
    Marta D’Alonzo, Laura Martincich, Agnese Fenoglio, Valentina Giannini, Lisa Cellini, Viola Liberale, Nicoletta Biglia

    Preoperative evaluation of nipple-areola complex (NAC) tumour involvement is crucial to select patients candidates for nipple-sparing mastectomy. Our aim was to validate a previously developed automated method able to compute the three-dimensional (3D) tumour-to-NAC distance (the most predictive parameter of nipple involvement), using magnetic resonance imaging (MRI) datasets acquired with a scanner and protocol different from those of the development phase.

  • Performance of machine learning software to classify breast lesions using BI-RADS radiomic features on ultrasound images
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-08-05
    Eduardo Fleury, Karem Marcomini

    The purpose of this work was to evaluate computable Breast Imaging Reporting and Data System (BI-RADS) radiomic features to classify breast masses on ultrasound B-mode images.

  • Correcting versus resolving respiratory motion in free-breathing whole-heart MRA: a comparison in patients with thoracic aortic disease
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-07-31
    Robert E. Stroud, Davide Piccini, U. Joseph Schoepf, John Heerfordt, Jérôme Yerly, Lorenzo Di Sopra, Jonathan D. Rollins, Andreas M. Fischer, Pal Suranyi, Akos Varga-Szemes

    Whole-heart magnetic resonance angiography (MRA) requires sophisticated methods accounting for respiratory motion. Our purpose was to evaluate the image quality of compressed sensing-based respiratory motion-resolved three-dimensional (3D) whole-heart MRA compared with self-navigated motion-corrected whole-heart MRA in patients with known thoracic aorta dilation.

  • The future of radiology is now: the first 100 articles published in European Radiology Experimental
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-07-26
    Francesco Sardanelli

    European Radiology Experimental reached the first 100 articles published in two years. Rejection rate was 30%, publication rate increased from 3.5/month in the first 12-month period to 4.8/month in the second 12-month period. The journal metrics were: 25 days from submission to first decision, 96 days from submission to acceptance, and 69 days from acceptance to publication. At the end of May 2019, we accumulated a total of 82,367 article accesses, 541 Altmetric score, and 110 citations for 92 published articles. Europe accounted for 85% of article origin. One third of corresponding authors were not radiologists/radiology residents, but were rather mainly physicists, engineers, or computer scientists. The distribution among subspecialties/body parts was well balanced; 9% of the topics regarded patient’s safety, radioprotection, or contrast media. Magnetic resonance imaging (MRI) and computed tomography (CT) accounted for 71% of the articles. Twenty-two percent of original articles/technical notes reported on animal models, 15% on phantoms, 3% on in silico, 2% on human cadavers, and 2% on cells. Nine articles regarded artificial intelligence and/or radiomics, and 2 regarded augmented reality. Of 100 articles, 57 declared funding sources. A total of 517 independent reviews were performed by 92 reviewers. The five articles quoted the most regarded augmented reality, spectral photon-counting CT, artificial intelligence, MRI radiomics, and diffusion tensor imaging of the musculoskeletal and peripheral nerve systems. The journal is complying with aims and scope of its “experimental” profile.

  • Analysis of a multicentre cloud-based CT dosimetric database: preliminary results
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-07-16
    Francesca Calderoni, Federica Campanaro, Paola Enrica Colombo, Mauro Campoleoni, Cristina De Mattia, Federica Rottoli, Giannicola Galetta, Fabio Zucconi, Andrea Pola, Andrea Righini, Fabio Triulzi, Angelo Vanzulli, Alberto Torresin

    To manage and analyse dosimetric data provided by computed tomography (CT) scanners from four Italian hospitals.

  • Imaging features in post-mortem x-ray dark-field chest radiographs and correlation with conventional x-ray and CT
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-07-11
    Alexander A. Fingerle, Fabio De Marco, Jana Andrejewski, Konstantin Willer, Lukas B. Gromann, Wolfgang Noichl, Fabian Kriner, Florian Fischer, Christian Braun, Hanns-Ingo Maack, Thomas Pralow, Thomas Koehler, Peter B. Noël, Felix Meurer, Dominik Deniffel, Andreas P. Sauter, Bernhard Haller, Daniela Pfeiffer, Ernst J. Rummeny, Julia Herzen, Franz Pfeiffer

    Although x-ray dark-field imaging has been intensively investigated for lung imaging in different animal models, there is very limited data about imaging features in the human lungs. Therefore, in this work, a reader study on nine post-mortem human chest x-ray dark-field radiographs was performed to evaluate dark-field signal strength in the lungs, intraobserver and interobserver agreement, and image quality and to correlate with findings of conventional x-ray and CT.

  • Embolisation of pulmonary arteriovenous malformations using high-frequency jet ventilation: benefits of minimising respiratory motion.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-07-10
    Emanuele Boatta,Roberto Luigi Cazzato,Pierre De Marini,Mathieu Canuet,Julien Garnon,Bob Heger,Thi Mai Bernmann,Nitin Ramamurthy,Christine Jahn,Marc Lopez,Afshin Gangi

    BACKGROUND To evaluate patient radiation dose and procedural duration recorded during pulmonary arteriovenous malformation (PAVM) embolisation performed using high-frequency jet ventilation (HFJV) as compared with conventional intermittent positive pressure ventilation (IPPV) METHODS: Patients undergoing PAVM embolisation with HFJV assistance after April 2017 were retrospectively identified as group A, and those treated with IPPV before April 2017 as group B. Primary outcomes were patient radiation dose and procedural duration between groups A and B. Secondary outcomes were difference in diaphragmatic excursion between groups A and B, in group A with/without HFJ assistance, technical/clinical success, and complications. RESULTS Twelve PAVMs were embolised in 5 patients from group A, and 15 PAVMs in 10 patients from group B. Mean patient radiation was significantly lower in group A than in group B (54,307 ± 33,823 mGy cm2 [mean ± standard deviation] versus 100,704 ± 43,930 mGy cm2; p = 0.022). Procedural duration was 33.4 ± 16.1 min in group A versus 57.4 ± 14.9 min in group B (p = 0.062). Diaphragmatic excursion was significantly lower in group A (1.3 ± 0.4 mm) than in group B (19.7 ± 5.2 mm; p < 0.001) and lower with near statistical significance in group A with HFJV than without HFJV (1.3 ± 0.4 mm versus 10.9 ± 3.1 mm; p = 0.062). Technical and clinical success was 100% in both groups, without relevant complications. CONCLUSION HFJV-assisted PAVM embolisation is a safe, feasible technique resulting in reduced patient radiation doses and procedural time.

  • Timing optimization of low-dose first-pass analysis dynamic CT myocardial perfusion measurement: validation in a swine model.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-04-05
    Logan Hubbard,Shant Malkasian,Yixiao Zhao,Pablo Abbona,Sabee Molloi

    BACKGROUND Myocardial perfusion measurement with a low-dose first-pass analysis (FPA) dynamic computed tomography (CT) perfusion technique depends upon acquisition of two whole-heart volume scans at the base and peak of the aortic enhancement. Hence, the objective of this study was to validate an optimal timing protocol for volume scan acquisition at the base and peak of the aortic enhancement. METHODS Contrast-enhanced CT of 28 Yorkshire swine (weight, 55 ± 24 kg, mean ± standard deviation) was performed under rest and stress conditions over 20-30 s to capture the aortic enhancement curves. From these curves, an optimal timing protocol was simulated, where one volume scan was acquired at the base of the aortic enhancement while a second volume scan was acquired at the peak of the aortic enhancement. Low-dose FPA perfusion measurements (PFPA) were then derived and quantitatively compared to the previously validated retrospective FPA perfusion measurements as a reference standard (PREF). The 32-cm diameter volume CT dose index, [Formula: see text] and size-specific dose estimate (SSDE) of the low-dose FPA perfusion protocol were also determined. RESULTS PFPA were related to the reference standard by PFPA = 0.95 · PREF + 0.07 (r = 0.94, root-mean-square error = 0.27 mL/min/g, root-mean-square deviation = 0.04 mL/min/g). The [Formula: see text] and SSDE of the low-dose FPA perfusion protocol were 9.2 mGy and 14.6 mGy, respectively. CONCLUSIONS An optimal timing protocol for volume scan acquisition at the base and peak of the aortic enhancement was retrospectively validated and has the potential to be used to implement an accurate, low-dose, FPA perfusion technique.

  • The effects of age at correction of aortic coarctation and recurrent obstruction on adolescent patients: MRI evaluation of wall shear stress and pulse wave velocity.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-06-22
    Joe F Juffermans,Ineke Nederend,Pieter J van den Boogaard,Arend D J Ten Harkel,Mark G Hazekamp,Hildo J Lamb,Arno A W Roest,Jos J M Westenberg

    BACKGROUND Coarctation patients before curative reconstruction are exposed to abnormal flow patterns which potentially could cause wall deterioration. This study evaluated the effect of age at correction on the pulse wave velocity (PWV) and peak wall shear stress (WSS) in adolescent patients with corrected coarctation. Effects of valve morphology and presence of reobstruction were also evaluated. METHODS Twenty-one patients aged 13.7 ± 2.6 years (mean ± standard deviation) were included (bicuspid aortic valve, n = 14; reobstruction, n = 9). Mean age at correction was 1.0 ± 1.8 years. PWV was determined from two high-temporal through-plane phase-contrast magnetic resonance imaging (MRI) acquisitions, for two segments: ascending aorta plus aortic arch and descending aorta. WSS was determined from four-dimensional flow MRI. Peak WSS over five systolic phases was determined for ascending aorta, aortic arch, and descending aorta. RESULTS Patients with tricuspid aortic valve showed a significant correlation between the age at correction and descending aorta PWV (rs = 0.80, p = 0.010). Significant differences were found between patients without and with reobstruction for peak WSS in the aortic arch (3.9 ± 1.3 Pa versus 6.5 ± 2.2 Pa, respectively; p = 0.003) and descending aorta (5.0 ± 1.3 Pa versus 6.7 ± 1.1 Pa, respectively; p = 0.005). CONCLUSIONS A prolonged period of abnormal haemodynamic exposure may result in increased aortic wall stiffening. The increased peak WSS as results of a reobstruction possibly promotes different disease progression, which endorse longitudinal follow-up examination of corrected coarctation patients.

  • Evaluation of response to conventional chemotherapy and radiotherapy by perfusion computed tomography in non-small cell lung cancer (NSCLC).
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-06-15
    Carmen Trinidad López,Javier De La Fuente Aguado,Roque Oca Pernas,Carlos Delgado Sánchez-Gracián,Eloisa Santos Armentia,Antonio Vaamonde Liste,Raquel Prada González,Miguel Souto Bayarri

    BACKGROUND To evaluate changes in perfusion computed tomography (PCT) parameters induced by treatment with conventional chemotherapy (CCT) alone or with CCT and radiation therapy (RT) in patients with non-small cell lung cancer (NSCLC) and to determine whether these changes correlate with response as defined by the response evaluation criteria in solid tumours version 1.1 (RECIST-1.1). METHODS Fifty-three patients with a histological diagnosis of NSCLC prospectively underwent PCT of the whole tumour, before/after CCT or before/after CCT and RT. Blood flow (BF), blood volume (BV), permeability (PMB), and mean transit time (MTT) were compared before and after treatment and with the response as defined by RECIST-1.1. The relationship between changes in the perfusion parameters and in tumour size was also evaluated. RESULTS PCT parameters decreased after treatment, significantly for BV (p = 0.002) and MTT (p = 0.027). The 30 patients with partial response had a significant decrease of 21% for BV (p = 0.006) and 17% for MTT (p = 0.031). A non-significant decrease in all perfusion parameters was found in patients with stable disease (p > 0.137). In patients with progressive disease, MTT decreased by 10% (p = 0.465) and the other parameters did not significantly vary (p > 0.809). No significant correlation was found between changes in size and PCT parameters (p > 0.145). CONCLUSIONS Treatment of NSCLC with platinum derivatives, with or without RT, induces changes in PCT parameters. Partial response is associated with a significant decrease in BV and MTT, attributable to the effect of the treatment on tumour vascularisation.

  • C-arm cone-beam CT parenchymal blood volume imaging for transarterial chemoembolization of hepatocellular carcinoma: implications for treatment planning and response.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-05-31
    Rory L O'Donohoe,Richard G Kavanagh,Alexis M Cahalane,Diarmaid D Houlihan,Jeffrey W McCann,Edmund Ronan Ryan

    We report on the feasibility of C-arm cone-beam computed tomography (CBCT) parenchymal blood volume imaging (PBVI) performed immediately following transarterial chemoembolization (TACE) of hepatocellular carcinoma (HCC) to assess the need for repeat treatment. Eighteen TACE procedures were included. A retrospective assessment was made for the presence or absence of residual disease requiring treatment on immediate post-TACE PBVI and on interval follow-up multidetector computed tomography (MDCT) or magnetic resonance imaging (MRI). In 9/18 cases, both PBVI and MDCT/MRI showed that no further treatment was required. In 6/18 cases, further treatment was required on both PBVI and MDCT/MRI. In three cases, PBVI showed that further treatment was not required but MDCT/MRI showed residual disease requiring repeat treatment. There were no cases with PBVI showing residual disease not detected on follow-up MDCT/MRI. The PBVI sensitivity for detecting disease requiring repeat TACE was 67% (95% confidence interval [CI] 30-93%), and specificity was 100% (95% CI 66-100%). The use of C-arm CBCT PBVI for the detection of residual viable tumor within a treated lesion immediately after TACE is feasible. It may allow repeat TACE to be planned without performing interval imaging with MDCT or MRI.

  • Reduction of operator radiation exposure using a passive robotic device during fluoroscopy-guided arterial puncture: an experimental study in a swine model.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-05-31
    Muhammad Umair Ahmad Khan,Chang-Hwan Yoon,Byung-Ju Yi

    BACKGROUND Vascular interventions imply radiation exposure to the operating physician (OP). To reduce radiation exposure, we propose a novel passive robotic device for fluoroscopy-guided arterial puncturing. METHODS X-ray dose rates were measured for a total of 30 fluoroscopy-guided puncture femoral arteries in 15 pigs. Fifteen punctures were performed with the device while the other 15 were performed without the device by an interventional cardiologist with 10 years of experience. Parametric t test was used. RESULTS The success rate with the device was 100%. Overall, the OP received more radiation (0.41 mSv/h) as compared to the assistant (0.06 mSv/h) (p <  0.001) and, amongst OP's body parts, hands received more radiation than other body parts (p <  0.001). The radiation dose rate to the OP's hands during arterial puncturing performed manually without the device was 0.95 ± 0.25 mSv/h whereas it was 0.14 ± 0.006 mSv/h using the device, resulting in an 85% reduction (p <  0.001). For the head, the dose was reduced from 0.16 mSv/h to 0.08 mSv/h (50% reduction, p <  0.001), and for the dominant arm, from 0.12 mSv/h to 0.07 mSv/h (42% reduction, p <  0.001). The fluoroscopy time was reduced from 4.5 ± 0.15 min to 4.3 ± 0.11 min device (p = 0.002). CONCLUSIONS In a swine model, fluoroscopy time and radiation exposure for the OP puncturing femoral artery were significantly reduced by using the passive robotic device.

  • Quantification of liver fibrosis: extracellular volume fraction using an MRI bolus-only technique in a rat animal model.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-05-31
    Julian A Luetkens,Sabine Klein,Frank Träber,Wolfgang Block,Frederic C Schmeel,Alois M Sprinkart,Daniel L R Kuetting,Frank E Uschner,Robert Schierwagen,Daniel Thomas,Jonel Trebicka,Guido M Kukuk

    BACKGROUND To determine the utility of single-contrast-bolus hepatic extracellular volume (ECV) fraction measurement at different time points to detect and quantify hepatic fibrosis. METHODS Different grades of liver fibrosis were induced in 23 male Sprague-Dawley rats by carbon-tetrachloride (CCl4) intoxication. In ten control rats, no fibrosis was induced. Native T1 values and ECV fraction were assessed by using quantitative magnetic resonance imaging (MRI) mapping; only one contrast bolus was applied (gadobutrol 0.1 mmol/kg). ECV values were determined 5, 15, and 25 min after injection. Hepatic fibrosis was quantified histologically by Sirius red staining. RESULTS For the 8-week-CCl4 group, the ECV fraction values obtained 5 (23.5 ± 4.8%, mean ± standard deviation), 15 (23.6 ± 4.8%), and 25 min (23.7 ± 4.7%) after injection were constant over time (p = 0.998); constant data 5-25 min after injection were also observed for the 16-week-CCl4 group and controls. Liver ECV after 15 min significantly increased with the severity of fibrosis: 18.0 ± 3.0% (controls) versus 23.6 ± 4.8% (8-week-CCl4) versus 30.5 ± 3.3% (16-week-CCl4) (p <  0.001). ECV values after 5, 15, and 25 min significantly correlated with Sirius red staining (p <  0.001 for all parameters). CONCLUSIONS Hepatic ECV obtained using a single-contrast-bolus technique can be measured 5, 15, and 25 min after injection, obtaining constant values over time, each of them being suitable to detect diffuse hepatic fibrosis. In clinical practice, post-contrast T1 relaxation times for liver ECV fraction determination might be obtained at only one time point.

  • Microbubbles as a contrast agent in grating interferometry mammography: an ex vivo proof-of-mechanism study.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-05-23
    Kristina Lång,Carolina Arboleda,Serafino Forte,Zhentian Wang,Sven Prevrhal,Thomas Koehler,Norbert Kuhn,Bernd David,Konstantins Jefimovs,Rahel A Kubik-Huch,Marco Stampanoni

    Grating interferometry mammography (GIM) is an experimental breast imaging method at the edge of being clinically implemented. Besides attenuation, GIM can measure the refraction and scattering of x-rays resulting in differential phase contrast (DPC) and dark-field (DF) images. In this exploratory study, we assessed the feasibility of using microbubbles as a contrast agent in GIM. Two millilitres of microbubbles and iodine were respectively injected into ex vivo breast phantoms, consisting of fresh chicken breasts. Native and postcontrast images were acquired with a clinically compatible GIM setup, operated at 38 kVp, 14-s acquisition time, and with a dose of 1.3 mGy. The visibility of the contrast agents was analysed in a side-by-side comparison by three radiologists. The contrast-to-noise-ratio (CNR) was calculated for each contrast agent. We found that both contrast agents were judged to be visible by the readers. The mean CNR was 3.1 ± 1.9 for microbubbles in DF and 24.2 ± 6.5 for iodine in attenuation. In conclusion, this is a first proof-of-mechanism study that microbubbles could be used as a contrast agent in clinically compatible GIM, due to their scattering properties, which implies the potential use of a contrast agent with a high safety profile in x-ray-based breast imaging.

  • Automatic segmentation and classification of breast lesions through identification of informative multiparametric PET/MRI features.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-04-29
    Wolf-Dieter Vogl,Katja Pinker,Thomas H Helbich,Hubert Bickel,Günther Grabner,Wolfgang Bogner,Stephan Gruber,Zsuzsanna Bago-Horvath,Peter Dubsky,Georg Langs

    BACKGROUND Multiparametric positron emission tomography/magnetic resonance imaging (mpPET/MRI) shows clinical potential for detection and classification of breast lesions. Yet, the contribution of features for computer-aided segmentation and diagnosis (CAD) need to be better understood. We proposed a data-driven machine learning approach for a CAD system combining dynamic contrast-enhanced (DCE)-MRI, diffusion-weighted imaging (DWI), and 18F-fluorodeoxyglucose (18F-FDG)-PET. METHODS The CAD incorporated a random forest (RF) classifier combined with mpPET/MRI intensity-based features for lesion segmentation and shape features, kinetic and spatio-temporal texture features, for lesion classification. The CAD pipeline detected and segmented suspicious regions and classified lesions as benign or malignant. The inherent feature selection method of RF and alternatively the minimum-redundancy-maximum-relevance feature ranking method were used. RESULTS In 34 patients, we report a detection rate of 10/12 (83.3%) and 22/22 (100%) for benign and malignant lesions, respectively, a Dice similarity coefficient of 0.665 for segmentation, and a classification performance with an area under the curve at receiver operating characteristics analysis of 0.978, a sensitivity of 0.946, and a specificity of 0.936. Segmentation but not classification performance of DCE-MRI improved with information from DWI and FDG-PET. Feature ranking revealed that kinetic and spatio-temporal texture features had the highest contribution for lesion classification. 18F-FDG-PET and morphologic features were less predictive. CONCLUSION Our CAD enables the assessment of the relevance of mpPET/MRI features on segmentation and classification accuracy. It may aid as a novel computational tool for exploring different modalities/features and their contributions for the detection and classification of breast lesions.

  • Microcomputed tomography of the femur of diabetic rats: alterations of trabecular and cortical bone microarchitecture and vasculature-a feasibility study.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-04-12
    David Zeitoun,Guavri Caliaperoumal,Morad Bensidhoum,Jean Marc Constans,Fani Anagnostou,Valérie Bousson

    BACKGROUND To better understand bone fragility in type 2 diabetes mellitus and define the contribution of microcomputed tomography (micro-CT) to the evaluation of bone microarchitecture and vascularisation, we conducted an in vitro preliminary study on the femur of Zucker diabetic fatty (ZDF) rats and Zucker lean (ZL) rats. We first analysed bone microarchitecture, then determined whether micro-CT allowed to explore bone vascularisation, and finally looked for a link between these parameters. METHODS Eight ZDF and six ZL rats were examined for bone microarchitecture (group 1), and six ZDF and six ZL rats were studied for bone vascularisation after Microfil® perfusion which is a radiopaque casting agent (group 2). In group 1, we used micro-CT to examine the trabecular and cortical bone microarchitecture of the femoral head, neck, shaft, and distal metaphysis. In group 2, micro-CT was used to study the blood vessels in the head, neck, and distal metaphysis. RESULTS Compared to ZL rats, the ZDF rats exhibited significantly lower trabecular bone volume and number and higher trabecular separation in the three locations (p = 0.02, p = 0.02, p = 0.003). Cortical porosity was significantly higher in the ZDF rats at the neck and shaft (p = 0.001 and p = 0.005). We observed a dramatically poorer bone vascularisation in the femur of ZDF rats, especially in distal metaphysis (p < 0.047). CONCLUSIONS Micro-CT demonstrated not only significant alterations in the bone microarchitecture of the femurs of ZDF rats, but also significant alterations in bone vascularisation. Further studies are required to demonstrate the causal link between poor vascularisation and impaired bone architecture.

  • Optimisation of ultrasound liver perfusion through a digital reference object and analysis tool.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-04-05
    Ángel Alberich-Bayarri,Jose Tomás-Cucarella,Alfredo Torregrosa-Lloret,Javier Sáiz Rodriguez,Luis Martí-Bonmatí

    BACKGROUND Conventional ultrasound (US) provides important qualitative information, although there is a need to evaluate the influence of the input parameters on the output signal and standardise the acquisition for an adequate quantitative perfusion assessment. The present study analyses how the variation in the input parameters influences the measurement of the perfusion parameters. METHODS A software tool with simulator of the conventional US signal was created, and the influence of the different input variables on the derived biomarkers was analysed by varying the image acquisition configuration. The input parameters considered were the dynamic range, gain, and frequency of the transducer. Their influence on mean transit time (MTT), the area under the curve (AUC), maximum intensity (MI), and time to peak (TTP) parameters as outputs of the quantitative perfusion analysis was evaluated. A group of 13 patients with hepatocarcinoma was analysed with both a commercial tool and an in-house developed software. RESULTS The optimal calculated inputs which minimise errors while preserving images' readability consisted of gain of 15 dB, dynamic range of 60 dB, and frequency of 1.5 MHz. The comparison between the in-house developed software and the commercial software provided different values for MTT and AUC, while MI and TTP were highly similar. CONCLUSION Input parameter selection introduces variability and errors in US perfusion parameter estimation. Our results may add relevant insight into the current knowledge of conventional US perfusion and its use in lesions characterisation, playing in favour of optimised standardised parameter configuration to minimise variability.

  • Respiratory- and cardiac-triggered three-dimensional sheath inked rapid acquisition with refocused echoes imaging (SHINKEI) of the abdomen for magnetic resonance neurography of the celiac plexus.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-03-30
    Cyril J Ferrer,Clemens Bos,Masami Yoneyama,Makoto Obara,Lisanne Kok,Maarten S van Leeuwen,Ronald L A W Bleys,Chrit T W Moonen,Lambertus W Bartels

    The visualisation of the celiac plexus using respiratory- and cardiac-triggered three-dimensional (3D) sheath inked rapid acquisition with refocused echoes imaging (SHINKEI) was evaluated. After ethical approval and written informed consent, eight volunteers (age 27 ± 5 years, mean ± standard deviation) were scanned at 1.5 and 3 T. Displacement of the celiac ganglia due to aortic pulsatility was studied on axial single-slice breath-hold balanced turbo field-echo cine sequences in five volunteers and found to be 3.0 ± 0.5 mm (left) and 3.1 ± 0.4 mm (right). Respiratory- and cardiac-triggered 3D SHINKEI images were compared to respiratory- and cardiac-triggered fat-suppressed 3D T2-weighted turbo spin-echo and respiratory-triggered 3D SHINKEI in all volunteers. Visibility of the celiac ganglia was rated by three radiologists as visible or non-visible. On 3D SHINKEI with double-triggering at 1.5 T, the left and right ganglia were seen by all observers in 7/8 and 8/8 volunteers, respectively. At 3 T, this was the case for 6/8 and 7/8 volunteers, respectively. The nerve-to-muscle signal ratio increased from 1.9 ± 0.5 on fat-suppressed 3D T2-weighted turbo spin-echo to 4.7 ± 0.8 with 3D SHINKEI. Anatomical validation was performed in a human cadaver. An expert in anatomy confirmed that the hyperintense structure visible on ex vivo 3D SHINKEI scans was the celiac plexus. In conclusion, double-triggering allowed visualisation of the celiac plexus using 3D SHINKEI at both 1.5 T and 3 T.

  • Hippocampus subfield volumetry after microsurgical or endovascular treatment of intracranial aneurysms-an explorative study.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-03-23
    Dennis M Hedderich,Tim J Reess,Matthias Thaler,Maria T Berndt,Sebastian Moench,Manuel Lehm,Tiberiu Andrisan,Christian Maegerlein,Bernhard Meyer,Yu-Mi Ryang,Claus Zimmer,Maria Wostrack,Benjamin Friedrich

    BACKGROUND To study hippocampus subfield volumes in patients after microsurgical clipping (MC) and/or endovascular coiling (EC) of intracranial aneurysms. METHODS Hippocampus subfield volumetry was performed using FreeSurfer v6.0 in 51 patients (35 females, mean age 54.9 ± 11.9 years, range 24-78 years). Visual inspection of image and segmentation quality was performed prior to statistical analyses. Multiple regression analysis, controlled for age, sex, and side of treatment, was used to assess the impact of prior MC and history of subarachnoid haemorrhage (SAH) on hippocampus subfield volumes (cornu ammonis (CA)-2/3, CA-4, subiculum). Partial correlation analyses were used to assess effect of multiple treatments on hippocampus subfield volumes. RESULTS Prior MC was significantly associated with lower hippocampal subfield volumes in MC patients for right and left CA-2/3 (β = -22.32 [-40.18, -4.45]; p = 0.016 and β = -20.03 [-39.38, -0.68]; p = 0.043) and right CA-4 (β = -17.00 [-33.86, 0.12]; p = 0.048). History of SAH was not significantly associated with hippocampal subfield volumes. We observed a higher disease burden in the MC cohort. The number of aneurysms correlated with right-sided hippocampal subfield volumes while the number of treatment interventions did not. CONCLUSION In this explorative study, we found that history of MC was significantly associated with lower volumes in distinct hippocampal subfields, which may be a consequence of a more extensive treatment. This could indicate specific atrophy of CA-2/3 after MC and should motivate hippocampal subfield assessment in larger cohorts.

  • Experimental application of an automated alignment correction algorithm for geological CT imaging: phantom study and application to sediment cores from cold-water coral mounds.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-03-15
    Stephan Skornitzke,Jacek Raddatz,André Bahr,Gregor Pahn,Hans-Ulrich Kauczor,Wolfram Stiller

    BACKGROUND In computed tomography (CT) quality assurance, alignment of image quality phantoms is crucial for quantitative and reproducible evaluation and may be improved by alignment correction. Our goal was to develop an alignment correction algorithm to facilitate geological sampling of sediment cores taken from a cold-water coral mount. METHODS An alignment correction algorithm was developed and tested with a CT acquisition at 120 kVp and 150 mAs of an image quality phantom. Random translation (maximum 15 mm) and rotation (maximum 2.86°) were applied and ground-truth was compared to parameters determined by alignment correction. Furthermore, mean densities were evaluated in four regions of interest (ROIs) placed in the phantom low-contrast section, comparing values before and after correction to ground truth. This process was repeated 1000 times. After validation, alignment correction was applied to CT acquisitions (140 kVp, 570 mAs) of sediment core sections up to 1 m in length, and sagittal reconstructions were calculated for sampling planning. RESULTS In the phantom, average absolute differences between applied and detected parameters after alignment correction were 0.01 ± 0.06 mm (mean ± standard deviation) along the x-axis, 0.11 ± 0.08 mm along the y-axis, 0.15 ± 0.07° around the x-axis, and 0.02 ± 0.02° around the y-axis, respectively. For ROI analysis, differences in densities were 63.12 ± 30.57, 31.38 ± 32.10, 18.27 ± 35.57, and 9.59 ± 26.37 HU before alignment correction and 1.22 ± 1.40, 0.76 ± 0.9, 0.45 ± 0.86, and 0.36 ± 0.48 HU after alignment correction, respectively. For sediment core segments, average absolute detected parameters were 3.93 ± 2.89 mm, 7.21 ± 2.37 mm, 0.37 ± 0.33°, and 0.21 ± 0.22°, respectively. CONCLUSIONS The alignment correction algorithm was successfully evaluated in the phantom and allowed a correct alignment of sediment core segments, thus aiding in sampling planning. Application to other tasks, like image quality analysis, seems possible.

  • An MRI-guided HIFU-triggered wax-coated capsule for supertargeted drug release: a proof-of-concept study.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-03-07
    Simon Matoori,Maurizio Roveri,Peter Tiefenboeck,Annatina Romagna,Olha Wuerthinger,Orpheus Kolokythas,Johannes M Froehlich

    BACKGROUND Externally controlling and monitoring drug release at a desired time and location is currently lacking in the gastrointestinal tract. The aim of the study was to develop a thermoresponsive wax-coated capsule and to trigger its release upon applying a magnetic resonance imaging (MRI)-guided high-intensity focused ultrasound (HIFU) pulse. METHODS Capsules containing a lyophilised gadolinium-based contrast agent (GBCA) were coated with a 1:1 (mass/mass) mixture of lanolin and cetyl alcohol (melting point ≈43 °C) and exposed to simulated gastric and intestinal fluids (United States Pharmacopoeia) at 37 °C for 2 and 24 h, respectively. In a HIFU gel phantom, wax-coated capsules (n = 3) were tracked based on their T1- and T2-hypointensity by 1.5-T T1- and T2-weighted MRI pre- and post-exposure to an MRI-guided HIFU pulse. RESULTS Lanolin/cetyl alcohol-coated capsules showed high resistance to simulated gastrointestinal fluids. In a gel phantom, an MRI-guided HIFU pulse punctured the wax coating, resulting in the hydration and release of the encapsulated lyophilised GBCA and yielding a T1-hyperintense signal close to the wax-coated capsule. CONCLUSION We provide the proof-of-concept of applying a non-invasive MRI-guided HIFU pulse to actively induce the disintegration of the wax-coated capsule, and a method to monitor the release of the cargo via T1-weighted MRI based on the hydration of an encapsulated lyophilised GBCA. The wax-coated capsule platform enables temporally and spatially supertargeted drug release via the oral route and promises to address a currently unmet clinical need for personalised local therapy in gastrointestinal diseases such as inflammatory bowel diseases and cancer.

  • Validation of two accelerated 4D flow MRI sequences at 3 T: a phantom study.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-02-27
    Sebastian Ebel,Lisa Hübner,Benjamin Köhler,Siegfried Kropf,Bernhard Preim,Bernd Jung,Matthias Grothoff,Matthias Gutberlet

    BACKGROUND Four-dimensional (4D) flow magnetic resonance imaging (MRI) sequences with advanced parallel imaging have the potential to reduce scan time with equivalent image quality and accuracy compared with standard two-dimensional (2D) flow MRI. We compared 4D flow to standard 2D flow sequences using a constant and pulsatile flow phantom at 3 T. METHODS Two accelerated 4D flow sequences (GRAPPA2 and k-t-GRAPPA5) were evaluated regarding the concordance of flow volumes, flow velocities, and reproducibility as well as dependency on measuring plane and velocity encoding (Venc). The calculated flow volumes and peak velocities of the phantom were used as reference standard. Flow analysis was performed using the custom-made software "Bloodline". RESULTS No significant differences in flow volume were found between the 2D, both 4D flow MRI sequences, and the pump reference (p = 0.994) or flow velocities (p = 0.998) in continuous and pulsatile flow. An excellent correlation (R = 0.99-1.0) with a reference standard and excellent reproducibility of measurements (R = 0.99) was achieved for all sequences. A Venc overestimated by up to two times had no impact on flow measurements. However, misaligned measuring planes led to an increasing underestimation of flow volume and mean velocity in 2D flow accuracy, while both 4D flow measurements were not affected. Scan time was significantly shorter for k-t-GRAPPA5 (1:54 ± 0:01 min, mean ± standard deviation) compared to GRAPPA2 (3:56 ± 0:02 min) (p = 0.002). CONCLUSIONS Both 4D flow sequences demonstrated equal agreement with 2D flow measurements, without impact of Venc overestimation and plane misalignment. The highly accelerated k-t-GRAPPA5 sequence yielded results similar to those of GRAPPA2.

  • 3D printing for heart valve disease: a systematic review.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-02-17
    Volkan Tuncay,Peter M A van Ooijen

    BACKGROUND Current developments showed a fast-increasing implementation and use of three-dimensional (3D) printing in medical applications. Our aim was to review the literature regarding the application of 3D printing to cardiac valve disease. METHODS A PubMed search for publications in English with the terms "3D printing" AND "cardiac valve", performed in January 2018, resulted in 64 items. After the analysis of the abstract and text, 27 remained related to the topic. From the references of these 27 papers, 7 papers were added resulting in a total of 34 papers. Of these, 5 were review papers, thus reducing the papers taken into consideration to 29. RESULTS The 29 papers showed that about a decade ago, the interest in 3D printing for this application area was emerging, but only in the past 2 to 3 years it really gained interest. Computed tomography is the most common imaging modality taken into consideration (62%), followed by ultrasound (28%), computer-generated models (computer-aided design) (7%), and magnetic resonance imaging (3%). Acrylonitrile butadiene styrene (4/14, 29%) and TangoPlus FullCure 930 (5/14, 36%) are the most used printing materials. Stereolithography (40%) and fused deposition modeling (30%) are the preferred printing techniques, while PolyJet (25%) and laser sintering (4%) are used in a minority of cases. The reported time ranges from 30 min to 3 days. The most reported application area is preoperative planning (63%), followed by training (19%), device testing (11%), and retrospective procedure evaluation (7%). CONCLUSIONS In most cases, CT datasets are used and models are printed for preoperative planning.

  • 3D convolutional neural networks applied to CT angiography in the detection of acute ischemic stroke.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-02-14
    Olli Öman,Teemu Mäkelä,Eero Salli,Sauli Savolainen,Marko Kangasniemi

    BACKGROUND The aim of this study was to investigate the feasibility of ischemic stroke detection from computed tomography angiography source images (CTA-SI) using three-dimensional convolutional neural networks. METHODS CTA-SI of 60 patients with a suspected acute ischemic stroke of the middle cerebral artery were randomly selected for this study; 30 patients were used in the neural network training, and the subsequent testing was performed using the remaining 30 patients. The training and testing were based on manually segmented lesions. Cerebral hemispheric comparison CTA and non-contrast computed tomography (NCCT) were studied as additional input features. RESULTS All ischemic lesions in the testing data were correctly lateralized, and a high correspondence to manual segmentations was achieved. Patients with a diagnosed stroke had clinically relevant regions labeled infarcted with a 0.93 sensitivity and 0.82 specificity. The highest achieved voxel-wise area under receiver operating characteristic curve was 0.93, and the highest Dice similarity coefficient was 0.61. When cerebral hemispheric comparison was used as an input feature, the algorithm performance improved. Only a slight effect was seen when NCCT was included. CONCLUSION The results support the hypothesis that an acute ischemic stroke lesion can be detected with 3D convolutional neural network-based software from CTA-SI. Utilizing information from the contralateral hemisphere appears to be beneficial for reducing false positive findings.

  • Evaluation of compressed sensing MRI for accelerated bowel motility imaging.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-02-07
    C S de Jonge,B F Coolen,E S Peper,A G Motaal,C Y Nio,I Somers,G J Strijkers,J Stoker,A J Nederveen

    BACKGROUND To investigate the feasibility of compressed sensing and parallel imaging (CS-PI)-accelerated bowel motility magnetic resonance imaging (MRI) and to compare its image quality and diagnostic quality to conventional sensitivity encoding (SENSE) accelerated scans. METHODS Bowel MRI was performed in six volunteers using a three-dimensional balanced fast field-echo sequence. Static scans were performed after the administration of a spasmolytic agent to prevent bowel motion artefacts. Fully sampled reference scans and multiple prospectively 3× to 7× undersampled CS-PI and SENSE scans were acquired. Additionally, fully sampled CS-PI and SENSE scans were retrospectively undersampled and reconstructed. Dynamic scans were performed using 5× to 7× accelerated scans in the presence of bowel motion. Retrospectively, undersampled scans were compared to fully sampled scans using structural similarity indices. All reconstructions were visually assessed for image quality and diagnostic quality by two radiologists. RESULTS For static imaging, the performance of CS-PI was lower than that of fully sampled and SENSE scans: the diagnostic quality was assessed as adequate or good for 100% of fully sampled scans, 95% of SENSE, but only for 55% of CS-PI scans. For dynamic imaging, CS-PI image quality was scored similar to SENSE at high acceleration. Diagnostic quality of all scans was scored as adequate or good; 55% of CS-PI and 83% of SENSE scans were scored as good. CONCLUSION Compared to SENSE, current implementation of CS-PI performed less or equally good in terms of image quality and diagnostic quality. CS-PI did not show advantages over SENSE for three-dimensional bowel motility imaging.

  • Quantitative DWI predicts event-free survival in children with neuroblastic tumours: preliminary findings from a retrospective cohort study.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-02-01
    Anna-Lydia Peschmann,Meinrad Beer,Bettina Ammann,Jens Dreyhaupt,Katharina Kneer,Ambros J Beer,Christian Beltinger,Daniel Steinbach,Holger Cario,Henning Neubauer

    BACKGROUND Quantitative diffusion-weighted imaging (DWI) probes into tissue microstructure in solid tumours. In this retrospective ethically approved study, we investigated DWI as a potential non-invasive predictor of tumour dignity and prognosis in paediatric patients with neuroblastic tumours. METHODS Nineteen consecutive patients with neuroblastoma (NB, n = 15), ganglioneuroblastoma (GNB, n = 1) and ganglioneuroma (GN, n = 3) underwent 3-T magnetic resonance imaging at first diagnosis and after 3-month follow-up, following a protocol including DWI (b = 50 and 800 s/mm2) in addition to standard sequences. All DWI scans were analysed for tumour volume assessment and apparent diffusion coefficient (ADC) calculation. Correlation with tumour pathology and risk factors (bone-marrow metastases, MYCN-amplification and 1p-deletion), therapeutic regime (observation versus chemotherapy) and clinical follow-up was evaluated. RESULTS At baseline, mean ADC in NB was lower than in GNB/GN (0.76 vs. 1.47 × 10-3 mm2/s, p = 0.003). An ADC cutoff ≤ 1.05 identified malignant disease with 100.0% sensitivity (95% confidence interval [CI] 29.2-100.0%) and 93.8% specificity (95% CI 69.8-99.8%). Initial ADC was < 0.80 in all NB patients with eventual tumour relapse. During follow-up, tumour ADC values increased in the observation group (NB/GN) without relapse (p = 0.043). In eventually relapsing tumours, ADC values at follow-up tended to decrease further despite reduction in tumour volume. CONCLUSIONS ADC values at first presentation differed significantly between malignant and benign neuroblastic tumours. Low baseline ADC was predictive of tumour progression and relapse in NB patients. With therapy, increasing ADC values appeared to predict relapse-free survival, while a decreasing ADC during therapy was an indicator of poor prognosis.

  • Quantitative CT-based bone strength parameters for the prediction of novel spinal implant stability using resonance frequency analysis: a cadaveric study involving experimental micro-CT and clinical multislice CT.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-01-24
    Daisuke Nakashima,Ken Ishii,Yuji Nishiwaki,Hiromasa Kawana,Masahiro Jinzaki,Morio Matsumoto,Masaya Nakamura,Takeo Nagura

    BACKGROUND To predict conventional test forces (peak torque and pull-out force) and a new test force (implant stability quotient [ISQ] value of a spinal pedicle screw) from computed tomography (CT) parameters, including micro-architectural parameters, using high-resolution micro-CT and clinical multislice CT (MSCT) in human cadaveric vertebrae. METHODS Micro-CT scans before/after screw insertion (n = 68) and MSCT scans before screw insertion (n = 58) of human cadaveric vertebrae were assessed for conventional test forces and ISQ value. Three-dimensional volume position adjustment between pre-insertion micro-CT and MSCT scans and post-insertion scans (micro-CT) was performed to extract the volume of the cancellous bone surrounding the pedicle screw. The following volume bone mineral density and micro-architectural parameters were calculated: bone volume fraction, bone surface density (bone surface/total volume (BS/TV)), trabecular thickness, trabecular separation, trabecular number, structure model index, and number of nodes (branch points) of the cancellous bone network/total volume (NNd/TV) using Spearman's rank correlation coefficient with Bonferroni correction. RESULTS Conventional test forces showed the strongest correlation with BS/TV: peak torque, ρ = 0.811, p = 4.96 × 10-17(micro-CT) and ρ = 0.730, p = 7.87 × 10-11 (MSCT); pull-out force, ρ = 0.730, p = 1.64 × 10-12 (micro-CT) and ρ = 0.693, p = 1.64 × 10-9 (MSCT). ISQ value showed the strongest correlation with NNd/TV: ρ = 0.607, p = 4.01 × 10-8 (micro-CT) and ρ = 0.515, p = 3.52 × 10-5 (MSCT). CONCLUSIONS Test forces, including the ISQ value, can be predicted using micro-CT and MSCT parameters. This is useful for establishing a preoperative fixation strength evaluation system.

  • In vivo canine study of three different coatings applied to p64 flow-diverter stents: initial biocompatibility study.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-01-24
    Rosa Martínez Moreno,Pervinder Bhogal,Tim Lenz-Habijan,Catrin Bannewitz,Adnan Siddiqui,Pedro Lylyk,Ralf Hannes,Hermann Monstadt,Hans Henkes

    BACKGROUND Flow-diverter stents (FDSs) have revolutionised the treatment of intracranial aneurysms. However, associated dual antiplatelet treatment is mandatory. We investigated the biocompatibility of three proprietary antithrombogenic coatings applied to FDSs. METHODS After Institutional Animal Care and Use Committee approval, four domestic juvenile female dogs (weight 19.9 ± 0.9 kg, mean ± standard deviation) were commenced on three different oral antiplatelet regimes: no medication (n = 1), acetylsalicylic acid (n = 2), and acetylsalicylic acid and clopidogrel (n = 1). Four p64 FDSs were randomly implanted into the subclavian, common carotid, and external carotid arteries of each dog, including both uncoated p64 stents and p64 stents coated with three different antithrombogenic hydrophilic coating (HPC). Angiography and histological examinations were performed. Wilcoxon/Kruskal-Wallis and ANOVA were used with p value < 0.05 considered as significant. RESULTS Minimal inflammatory cell infiltration and no device-associated granulomatous cell inflammation were observed. No significant difference in adventitial inflammation (p = 0.522) or neointimal/medial inflammation (p = 0.384) between coated and uncoated stents as well as between the different stent groups regarding endothelial cell loss, surface fibrin/platelet deposition, medial smooth muscle cell loss, or adventitial fibrosis were found. Acute self-limiting thrombus formed on 6/16 implants (37.5%), and all of the thrombi were noted on devices implanted in the common or external carotid artery irrespective of the surface coating. Two of 12 p64 HPC-coated stents (16.7%) and 1/4 uncoated p64 stents (25%) showed severe or complete stenosis at delayed angiography. CONCLUSIONS In these preliminary in vivo experiments, HPC-coated p64 FDSs appeared to be biocompatible, without acute inflammation.

  • Ultrasound-guided percutaneous procedures in pancreatic diseases: new techniques and applications.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2019-01-24
    Mirko D'Onofrio,Alessandro Beleù,Riccardo De Robertis

    Ultrasound (US) is not only an important diagnostic tool for the evaluation of the pancreas, but is also a fundamental imaging technique to guide percutaneous interventions for several pancreatic diseases (fluid aspiration and drainage; invasive diagnosis by means fine-needle aspiration and core-needle biopsy; tumour ablation by radiofrequency, microwaves, irreversible electroporation, cryoablation, and high-intensity focused US). Technical improvements, such as contrast media and fusion imaging, have recently increased precision and safety and reduced procedure-related complications. New treatment US techniques for the ablation of pancreatic tumours, such as contrast-enhanced US and multimodality fusion imaging, have been recently developed and have elicited a growing interest worldwide. The purpose of this article was to review the most up-to-date role of US in percutaneous procedures for pancreatic diseases.

  • Evolution of prostate MRI: from multiparametric standard to less-is-better and different-is better strategies.
    Eur. Radiol. Exp. (IF 0) Pub Date : null
    Rossano Girometti,Lorenzo Cereser,Filippo Bonato,Chiara Zuiani

    Multiparametric magnetic resonance imaging (mpMRI) has become the standard of care to achieve accurate and reproducible diagnosis of prostate cancer. However, mpMRI is quite demanding in terms of technical rigour, patient's tolerability and safety, expertise in interpretation, and costs. This paper reviews the main technical strategies proposed as less-is-better solutions for clinical practice (non-contrast biparametric MRI, reduction of acquisition time, abbreviated protocols, computer-aided diagnosis systems), discussing them in the light of the available evidence and of the concurrent evolution of Prostate Imaging Reporting and Data System (PI-RADS). We also summarised research results on those advanced techniques representing an alternative different-is-better line of the still ongoing evolution of prostate MRI (quantitative diffusion-weighted imaging, quantitative dynamic contrast enhancement, intravoxel incoherent motion, diffusion tensor imaging, diffusional kurtosis imaging, restriction spectrum imaging, radiomics analysis, hybrid positron emission tomography/MRI).

  • Biomechanical effects of osteoplasty with or without Kirschner wire augmentation on long bone diaphyses undergoing bending stress: implications for percutaneous imaging-guided consolidation in cancer patients.
    Eur. Radiol. Exp. (IF 0) Pub Date : null
    Roberto Luigi Cazzato,Guillaume Koch,Julien Garnon,Nitin Ramamurthy,Jérémie Jégu,Philippe Clavert,Afshin Gangi

    BACKGROUND Osteoplasty has been discouraged in long bones. However, despite a substantial lack of pre-clinical biomechanical tests, multiple clinical studies have implemented a wide range of techniques to optimise long bone osteoplasty. The aim of the present study is to evaluate the biomechanical properties of osteoplasty alone and in combination with Kirschner wires (K-wires) in a cadaveric human diaphyseal model undergoing 3-point bending stress. METHODS Thirty unpaired human cadaveric hemi-tibia specimens were randomly assigned to receive no consolidation (group 1, n = 10), osteoplasty alone (group 2, n = 10), or K-wires augmented osteoplasty (group 3, n = 10). Specimens were tested on a dedicated servo-hydraulic machine using a 3-point bending test. Fracture load was calculated for each specimen; two-sample Wilcoxon rank-sum tests were used to assess differences between groups. RESULTS Median volume of polymethyl methacrylate injected was 18 mL for group 2 (25th-50th percentile 15-21 mL) and 19 mL for group 3 (25th-50th percentile 17-21). There were no significant differences in fracture load between groups 1 and 2 (z = - 0.793; p = 0.430), between groups 1 and 3 (z = - 0.944; p = 0.347), and between groups 2 and 3 (z = - 0.454; p = 0.650). Fractures through the cement occurred in 4 of 30 cases (13.3%); there were no K-wires fractures. CONCLUSIONS Osteoplasty with or without K-wires augmentation does not improve the resistance of diaphyseal bone to bending stresses.

  • A visual quality control scale for clinical arterial spin labeling images.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2018-12-21
    S M Fallatah,F B Pizzini,B Gomez-Anson,J Magerkurth,E De Vita,S Bisdas,H R Jäger,H J M M Mutsaerts,X Golay

    BACKGROUND Image-quality assessment is a fundamental step before clinical evaluation of magnetic resonance images. The aim of this study was to introduce a visual scoring system that provides a quality control standard for arterial spin labeling (ASL) and that can be applied to cerebral blood flow (CBF) maps, as well as to ancillary ASL images. METHODS The proposed image quality control (QC) system had two components: (1) contrast-based QC (cQC), describing the visual contrast between anatomical structures; and (2) artifact-based QC (aQC), evaluating image quality of the CBF map for the presence of common types of artifacts. Three raters evaluated cQC and aQC for 158 quantitative signal targeting with alternating radiofrequency labelling of arterial regions (QUASAR) ASL scans (CBF, T1 relaxation rate, arterial blood volume, and arterial transient time). Spearman correlation coefficient (r), intraclass correlation coefficients (ICC), and receiver operating characteristic analysis were used. RESULTS Intra/inter-rater agreement ranged from moderate to excellent; inter-rater ICC was 0.72 for cQC, 0.60 for aQC, and 0.74 for the combined QC (cQC + aQC). Intra-rater ICC was 0.90 for cQC; 0.80 for aQC, and 0.90 for the combined QC. Strong correlations were found between aQC and CBF maps quality (r = 0.75), and between aQC and cQC (r = 0.70). A QC score of 18 was optimal to discriminate between high and low quality clinical scans. CONCLUSIONS The proposed QC system provided high reproducibility and a reliable threshold for discarding low quality scans. Future research should compare this visual QC system with an automatic QC system.

  • Contrast-enhanced ultrasound for ovary assessment in a murine model: preliminary findings on the protective role of a gonadotropin-releasing hormone analogue from chemotherapy-induced ovarian damage.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2018-12-20
    Massimo Venturini,Alice Bergamini,Laura Perani,Ana Maria Sanchez,Elena Giulia Rossi,Anna Colarieti,Micaela Petrone,Francesco De Cobelli,Alessandro Del Maschio,Paola Viganò,Giorgia Mangili,Massimo Candiani,Carlo Tacchetti,Antonio Esposito

    The prolonged, gonadotoxic effect of chemotherapy can finally lead to infertility in female cancer survivors. There is controversial evidence regarding the protective role of gonadotropin-releasing hormone analogue (GnRH-a) on chemotherapy-induced ovarian damage. In the present study on a murine model, ultrasound (US) and contrast-enhanced US (CEUS) were firstly used to characterise ovarian glands in normal conditions to validate a preclinical model. In addition, preliminary findings were obtained on anatomical and vascular ovarian changes induced by GnRH-a based on decapeptyl administration. Ovaries were accurately assessed with US and CEUS in a murine model placed in prone position, providing quantitative and reproducible information. Ovaries were identified in 40/40 cases and CEUS analysis was successfully performed in 20/20 cases with 100% technical success. A statistically significant increase of the diameter of the dominant follicle at US and a statistically significant reduced vascularisation at CEUS in decapeptyl-treated mice compared to untreated control mice were recorded. Further studies using US and CEUS in the murine model combining GnRH-a and chemotherapeutic agents will be needed to obtain more translational information useful for clinical practice.

  • Changes in total choline concentration in the breast of healthy fertile young women in relation to menstrual cycle or use of oral contraceptives: a 3-T 1H-MRS study.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2018-12-19
    Giovanni Di Leo,Ileana Ioan,Maria Laura Luciani,Cecilia Midulla,Franca Podo,Francesco Sardanelli,Federica Pediconi

    BACKGROUND To evaluate changes in total choline (tCho) absolute concentration ([tCho]) in the breast of healthy fertile women in relation to menstrual cycle (MC) or use of oral contraceptives (OC). METHODS After institutional review board approval, we prospectively evaluated 40 healthy fertile volunteers: 20 with physiological MC, aged 28 ± 3 years (mean ± standard deviation; nOC group); 20 using OC, aged 26 ± 3 years (OC group). Hormonal assays and water-suppressed single-voxel 3-T proton magnetic resonance spectroscopy (1H-MRS) were performed on MC days 7, 14, and 21 in the nOC group and only on MC day 14 in the OC group. [tCho] was measured versus an external phantom. Mann-Whitney U test and Spearman coefficient were used; data are given as median and interquartile interval. RESULTS All spectra had good quality. In the nOC group, [tCho] (mM) did not change significantly during MC: 0.8 (0.3-2.4) on day 7, 0.9 (0.4-1.2) on day 14, and 0.4 (0.2-0.8) on day 21 (p = 0.963). In the OC group, [tCho] was 0.7 (0.2-1.7) mM. The between-groups difference was not significant on all days (p ≥ 0.411). All hormones except prolactin changed during MC (p ≤ 0.024). In the OC group, [tCho] showed a borderline correlation with estradiol (r = 0.458, p = 0.056), but no correlation with other hormones (p ≥ 0.128). In the nOC group, [tCho] negatively correlated with prolactin (r = -0.587, p = 0.006) on day 7; positive correlation was found with estradiol on day 14 (r = 0.679, p = 0.001). CONCLUSIONS A tCho peak can be detected in the normal mammary gland using 3-T 1H-MRS. The [tCho] in healthy volunteers was 0.4-0.9 mM, constant over the MC and independent of OC use.

  • Big data, artificial intelligence, and structured reporting.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2018-12-06
    Daniel Pinto Dos Santos,Bettina Baeßler

    The past few years have seen a considerable rise in interest towards artificial intelligence and machine learning applications in radiology. However, in order for such systems to perform adequately, large amounts of training data are required. These data should ideally be standardised and of adequate quality to allow for further usage in training of artificial intelligence algorithms. Unfortunately, in many current clinical and radiological information technology ecosystems, access to relevant pieces of information is difficult. This is mostly because a significant portion of information is handled as a collection of narrative texts and interoperability is still lacking. This review aims at giving a brief overview on how structured reporting can help to facilitate research in artificial intelligence and the context of big data.

  • Abdominal CT: a radiologist-driven adjustment of the dose of iodinated contrast agent approaches a calculation per lean body weight.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2018-12-06
    Moreno Zanardo,Fabio Martino Doniselli,Anastassia Esseridou,Stefania Tritella,Chiara Mattiuz,Laura Menicagli,Giovanni Di Leo,Francesco Sardanelli

    BACKGROUND The contrast agent (CA) dose for abdominal computed tomography (CT) is typically based on patient total body weight (TBW), ignoring adipose tissue distribution. We report on our experience of dosing according to the lean body weight (LBW). METHODS After Ethics Committee approval, we retrospectively screened 219 consecutive patients, 18 being excluded for not matching the inclusion criteria. Thus, 201 were analysed (106 males), all undergoing a contrast-enhanced abdominal CT with iopamidol (370 mgI/mL) or iomeprol (400 mgI/mL). LBW was estimated using validated formulas. Liver contrast-enhancement (CEL) was measured. Data were reported as mean ± standard deviation. Pearson correlation coefficient, ANOVA, and the Levene test were used. RESULTS Mean age was 66 ± 13 years, TBW 72 ± 15 kg, LBW 53 ± 11 kg, and LBW/TBW ratio 74 ± 8%; body mass index was 26 ± 5 kg/m2, with 9 underweight patients (4%), 82 normal weight (41%), 76 overweight (38%), and 34 obese (17%). The administered CA dose was 0.46 ± 0.06 gI/kg of TBW, corresponding to 0.63 ± 0.09 gI/kg of LBW. A negative correlation was found between TBW and CA dose (r = -0.683, p < 0.001). CEL (Hounsfield units) was 51 ± 18 in underweight patients, 44 ± 8 in normal weight, 42 ± 9 in overweight, and 40 ± 6 in obese, with a significant difference for both mean (p = 0.004) and variance (p < 0.001). A low but significant positive correlation was found between CEL and CA dose in gI per TBW (r = 0.371, p < 0.001) or per LBW (r = 0.333, p < 0.001). CONCLUSIONS The injected CA dose was highly variable, with obese patients receiving a lower dose than underweight patients, as a radiologist-driven 'compensation effect'. Diagnostic abdomen CT examinations may be obtained using 0.63 gI/kg of LBW.

  • Using body mass index to estimate individualised patient radiation dose in abdominal computed tomography.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2018-11-30
    Siobhan O'Neill,Richard G Kavanagh,Brian W Carey,Niamh Moore,Michael Maher,Owen J O'Connor

    BACKGROUND The size-specific dose estimate (SSDE) is a dose-related metrics that incorporates patient size into its calculation. It is usually derived from the volume computed tomography dose index (CTDIvol) by applying a conversion factor determined from manually measured anteroposterior and lateral skin-to-skin patient diameters at the midslice level on computed tomography (CT) localiser images, an awkward, time-consuming, and not highly reproducible technique. The objective of this study was to evaluate the potential for the use of body mass index (BMI) as a size-related metrics alternative to the midslice effective diameter (DE) to obtain a size-specific dose (SSDE) in abdominal CT. METHODS In this retrospective study of patients who underwent abdominal CT for the investigation of inflammatory bowel disease, the DE was measured on the midslice level on CT-localiser images of each patient. This was correlated with patient BMI and the linear regression equation relating the quantities was calculated. The ratio between the internal and the external abdominal diameters (DRATIO) was also measured to assess correlation with radiation dose. Pearson correlation analysis and linear regression models were used. RESULTS There was good correlation between DE and patient BMI (r = 0.88). An equation allowing calculation of DE from BMI was calculated by linear regression analysis as follows: DE = 0.76 (BMI) + 9.4. A weak correlation between radiation dose and DRATIO was demonstrated (r = 0.45). CONCLUSIONS Patient BMI can be used to accurately estimate DE, obviating the need to measure anteroposterior and lateral diameters in order to calculate a SSDE for abdominal CT.

  • The potential toxic impact of different gadolinium-based contrast agents combined with 7-T MRI on isolated human lymphocytes.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2018-11-30
    Björn Friebe,Frank Godenschweger,Mahsa Fatahi,Oliver Speck,Dirk Roggenbuck,Dirk Reinhold,Annika Reddig

    BACKGROUND To investigate a potentially amplifying genotoxic or cytotoxic effect of different gadolinium-based contrast agents (GBCAs) in combination with ultra-high-field 7-T magnetic resonance imaging (MRI) exposure in separated human peripheral blood lymphocytes. METHODS This in vitro study was approved by the local ethics committee and written informed consent was obtained from all participants. Isolated lymphocytes from twelve healthy donors were incubated with gadobutrol, gadoterate meglumine, gadodiamide, gadopentetate dimeglumine, or gadoxetate either alone or combined with 7-T MRI (1 h). Deoxyribonucleic acid (DNA) double-strand breaks were assessed 15 min after MRI exposure by automated γH2AX foci quantification. Cytotoxicity was determined at later endpoints by Annexin V/propidium iodide apoptosis assay (24 h) and [3H]-thymidine proliferation test (72 h). As a reference, lymphocytes from four different donors were exposed analogously to iodinated contrast agents (iomeprol, iopromide) in combination with computed tomography. RESULTS Baseline γH2AX levels (0.08 ± 0.02 foci/cell) were not significantly (p between 0.135 and 1.000) enhanced after administration of GBCAs regardless of MRI exposure. In contrast to the two investigated macrocyclic GBCAs, lymphocytes exposed to the three linear GBCAs showed a dose-dependent increase in apoptosis (maximum 186% of unexposed control, p < 0.001) and reduced proliferation rate (minimum 0.7% of unexposed control, p < 0.001). However, additional 7-T MRI co-exposure did not alter GBCA-induced cytotoxicity. CONCLUSIONS Exposure of lymphocytes to different GBCAs did not reveal significant induction of γH2AX foci, and enhanced cytotoxicity was only observed in lymphocytes treated with the linear GBCAs used in this study, independent of additional 7-T MRI co-exposure.

  • The impact of sarcopenia and myosteatosis on postoperative outcomes in patients with inflammatory bowel disease.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2018-11-22
    Stephen O'Brien,Richard G Kavanagh,Brian W Carey,Michael M Maher,Owen J O'Connor,Emmet J Andrews

    BACKGROUND Inflammatory bowel disease (IBD) is a relatively common disorder with significant associated morbidity. Sarcopenia and myosteatosis are associated with adverse postoperative outcomes. This study investigated outcomes in IBD patients undergoing surgical resection relative to the presence of sarcopenia and myosteatosis. METHODS A retrospective analysis of a prospectively maintained surgical database was conducted. All patients undergoing elective or emergency resection for IBD between 2011 and 2016, with a contemporaneous perioperative computed tomography (CT) scan, were included. Patient demographics, clinical and biochemical measurements were collected. Skeletal muscle index and attenuation were measured on perioperative CT scans using Osirix version 5.6.1. Univariate and multivariate regression analysis was used to identify risk factors for adverse postoperative outcomes. RESULTS Seventy-seven patients (46 male, 31 female; mean age 42 years, range 20-80 years) were included. Thirty patients (30%) had sarcopenia and 26 (34%) had myosteatosis. Myosteatosis was significantly associated with increased hospital stay postoperatively (9 versus 13 days). Sarcopenia and myosteatosis were associated with hospital readmission within 30 days on univariate analysis. Multivariate regression analysis demonstrated an independent association between myosteatosis and hospital readmission. Sixteen patients (21%) had a clinically relevant postoperative complication, but an association with sarcopenia and myosteatosis was not observed. A neutrophil-lymphocyte ratio greater than 5 was predictive of clinically relevant postoperative complications on multivariate regression analysis. CONCLUSIONS Myosteatosis was associated with increased hospital stay and increased 30-day hospital readmission rates on multivariate regression analysis. Sarcopenia and myosteatosis in IBD were not associated with clinically relevant postoperative complications.

  • Concentrated pineapple juice for visualisation of the oesophagus during magnetic resonance angiography before atrial fibrillation radiofrequency catheter ablation.
    Eur. Radiol. Exp. (IF 0) Pub Date : 2018-11-22
    Riccardo Faletti,Marco Gatti,Andrea Di Chio,Marco Fronda,Matteo Anselmino,Federico Ferraris,Fiorenzo Gaita,Paolo Fonio

    The purpose of this study was to compare in vitro pineapple juice and a solution of concentrated pineapple juice with a paramagnetic contrast agent in order to determine the feasibility of using the solution of concentrated pineapple juice in vivo for oesophagus visualisation at magnetic resonance angiography (MRA) before the radiofrequency catheter ablation procedure for atrial fibrillation. The pineapple juice was concentrated by a microwave heating evaporation process performed in a domestic microwave oven. Five grams of modified potato starch for every 40 mL of concentrated pineapple juice were added to the concentrated pineapple juice in order to thicken the solution. The solution resulted visually and quantitatively as hyperintense as the contrast agent in vitro (ratio = 1.02). in vivo, no technical difficulties were encountered during the MRA acquisition and a complete enhanced oesophagus was obtained in 37/38 patients (97.4%). The volumetric analysis and the three-dimensional reconstruction were feasible; the quality was rated as diagnostic in every patient. The intensified oesophagus was successfully merged into the electro-anatomical maps in all the patients. In summary, we demonstrated that this technique allows a feasible and safe oesophagus visualisation during MRA.

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上海纽约大学William Glover