Original Article
Pancreas, Biliary Tract, and Liver
Prospective, Same-Day, Direct Comparison of Controlled Attenuation Parameter With the M vs the XL Probe in Patients With Nonalcoholic Fatty Liver Disease, Using Magnetic Resonance Imaging–Proton Density Fat Fraction as the Standard

https://doi.org/10.1016/j.cgh.2019.11.060Get rights and content

Background & Aims

Controlled attenuation parameter (CAP) measurements using M probe have been reported to be lower than those of the XL-probe in detection of hepatic steatosis. However, there has been no direct comparison of CAP with the M vs the XL probe in patients with nonalcoholic fatty liver disease (NAFLD). We compared CAP with the M vs the XL probe for quantification of hepatic fat content, using magnetic resonance imaging proton density fat fraction (MRI-PDFF) as the standard.

Methods

We performed a prospective study of 100 adults (mean body mass index [BMI], 30.6 ± 4.7 kg/m2) with and without NAFLD, assessed by CAP with the M probe and XL probe on the same day, at a single research center, from November 2017 through November 2018. We then measured the MRI-PDFF as the reference standard. Outcomes were presence of hepatic steatosis, defined as MRI-PDFF ≥ 5%, and detection of hepatic fat content ≥ 10%, defined as MRI-PDFF ≥ 10%. We performed area under the receiver operating characteristic curve (AUROC) analyses to assess the diagnostic accuracy of CAP for each probe in detection of hepatic steatosis (MRI-PDFF ≥ 5%) and of hepatic fat content ≥ 10%.

Results

Of the study participants, 68% had an MRI-PDFF of 5% or more and 48% had an MRI-PDFF of 10% or more. The mean CAP measured by the M probe (310 ± 62 db/m) was significantly lower than by the X probe (317 ± 63 db/m) (P = .007). When M probe was used in participants with BMIs <30 kg/m2 and XL probe in participants with BMIs ≥30 kg/m2, the CAP measured by the M probe (312 ± 51.4 db/m) remained significantly lower than that of the XL probe (345 ± 47.6 db/m) (P = .0035.), when the MRI-PDFF was above 5%. The optimal threshold of CAP for the detection of MRI-PDFF≥5%, was 294 db/m with the M probe and 307 db/m with the XL probe. The optimal threshold of CAP for the detection of MRI-PDFF ≥ 10%, was 311 db/m with the M probe and 322 db/m with the XL probe. For only the XL probe, CAP measurements with an interquartile range below 30 dB/m detected an MRI-PDFF≥5% with a lower AUROC (0.97; 95% CI, 0.80–1.00) than CAP measurements with an interquartile range above 30 dB/m (AUROC, 0.82; 95% CI, 0.71–0.90) (P = .0129).

Conclusions

In an analysis of the same patients using CAP with the M probe and XL probe, with MRI-PDFF as the standard, we found that the M probe under-quantifies CAP values compared with the XL probe, independent of BMI. The type of probe should be considered when interpreting CAP data from patients with NAFLD.

Section snippets

Study Participant and Design

This is a prospective study designed to compare CAP measurement using M vs the XL probe for the detection of hepatic steatosis in participants prospectively recruited and screened for the presence of hepatic steatosis, using MRI-PDFF as reference. All participants underwent MRI-PDFF and CAP measurements using a FibroScan with both M and XL probes. We followed the Standards for Reporting of Diagnostic Accuracy guidelines in this study of CAP in detecting hepatic steatosis (Supplementary Table 1).

Study Participants

A total of 100 participants with or without NAFLD with MRI-PDFF assessment and CAP measurements using both M and XL probes were included in the analysis (Table 1). The majority of the participants (66%) had an MRI and CAP with the M and XL probes the same day and the mean time between MRI and CAP assessment was 11.3 (95% confidence interval [CI], 6.2–16.5) days. Both CAP measurements with the M and XL probes were significantly correlated, with hepatic fat content assessed by MRI-PDFF (

Main Findings

We conducted a prospective study including well-characterized American adults with NAFLD and without NAFLD who underwent CAP measurement using both the M and XL probes for the quantification of liver fat content and MRI-PDFF assessment as the gold standard. We report that CAP measurements using the M probe underestimate the hepatic fat content compared with CAP measurements using the XL probe for the same quantity of MRI-PDFF hepatic fat content, even when the probe is selected according to the

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    This article has an accompanying continuing medical education activity, also eligible for MOC credit, on page e95. Learning Objective–Upon completion of this activity, successful learners will be able to manage a patient with nonalcoholic fatty liver disease including noninvasive tests for the stage of the disease and treatment.

    Conflicts of interest The authors disclose no conflicts.

    Funding This work was supported by Atlantic Philanthropies, Inc, the John A. Hartford Foundation, OM, the Association of Specialty Professors, and the American Gastroenterological Association, and National Institutes of Health grant K23-DK090303 (to Rohit Loomba). Rohit Loomba is supported in part by the American Gastroenterological Association Foundation–Sucampo–ASP Designated Research Award in Geriatric Gastroenterology and by a T. Franklin Williams Scholarship Award. The project described and Rohit Loomba were partially supported by National Institute of Environmental Health Sciences grant 5P42ES010337 and National Center for Advancing Translational Sciences grant 5UL1TR001442. Claude B. Sirlin and Rohit Loomba also received support from the National Institute of Diabetes and Digestive and Kidney Diseases grant R01-DK106419. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health.

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