Elsevier

Journal of Neuroradiology

Volume 48, Issue 6, November 2021, Pages 432-437
Journal of Neuroradiology

Original Article
Limited positive predictive value of diffusion tensor tractography in determining clinically relevant white matter damage in brain stem cavernous malformations: A retrospective study in a single center surgical cohort,☆☆

https://doi.org/10.1016/j.neurad.2019.07.005Get rights and content

Highlights

  • DTT should be taken cautiously before drawing conclusions in brain stem cavernomas.

  • Clinically relevant damage of white matter tracts might not be detected by DTT.

  • DTT may over-estimate damage to the brain stem white matter tracts.

Abstract

Purpose

Diffusion tensor tractography (DTT) might reflect the postoperative clinical outcome of the patients with brain stem (BS) tumors correlating well with the neurological symptoms, but cavernous malformation (CM) is a hemorrhagic tumor prone to artifacts that may limit DTT. We set out to determine the correlation of DTT findings with the neurological examination before and after surgical resection in patients with BSCMs.

Materials and methods

DTT findings were evaluated bilaterally for fiber tract displacement or deviation, deformation and interruption in every patient before and after the surgery. Neurological examination was performed at admission, discharge and outpatient follow-up visit. The sensitivity, specificity, positive and negative predictive values of DTT were calculated both pre- and post-operatively.

Results

There were 25 patients (9 men 16 women) with a mean age of 39.5 ± 13.9 years. The mean size of the CMs was 6909 ± 8374 mm3 (range: 180–38,220 mm3) The mean follow-up time was 42.7 ± 23.2 months (range: 8 to 112 months). Preoperatively, the sensitivity, specificity, positive and negative predictive values of DTT for corticospinal tracts (CST) and medial lemnisci (ML) were 100%, 60%, 38.4%, 100% and 87.5%, 11.7%, 31.8%, 66.6%, respectively. Postoperatively, the sensitivity, specificity, positive and negative predictive values of DTT for CSTs and ML were 100%, 64.7%, 40%, 100% and 100%, 0%, 33.3%, 66.6%, respectively.

Conclusion

Positive findings on DTT such as fiber tract deviation, deformation, disruption or interruption should be taken cautiously before drawing conclusions of a clinically relevant damage of white matter tracts.

Introduction

Brain stem cavernous malformations (BSCM) are rare lesions and constitute 10–35% of all central nervous system (CNS) cavernous malformations. In addition to the mass effect on brain stem structures, they may also lead to fatal complications because cavernomas are prone to bleeding. The definitive treatment option is surgery with total or gross-total resection [1]. However, presence of major white matter tracts in the brain stem [2], makes surgical treatment and excision of BSCMs challenging and necessitates possessing detailed anatomical knowledge and neurosurgical experience. Diffusion tensor imaging (DTI) and diffusion tensor tractography (DTT), have therefore already been effectively utilized for this purpose and for the surgical planning of BSCMs. There is also emerging new high resolution techniques so-called tensor weighted imaging (TWI) which combines high-resolution anatomical images with tractography images [3]. DTT and DTI provide valuable information preoperatively corresponding to the clinical status of the patient [4], [5], [6], [7], [8]. In previous articles on DTT and BSCMs, it was also reported that DTT might reflect the postoperative clinical outcome of the patient correlating well with the neurological symptoms [9], [10]. Nonetheless, it is well-known that the susceptibility effects of chronic blood breakdown products (i.e. hemosiderin) inside the lesion itself is a potentially limiting factor to the signal acquired from the fiber tractography, and hence may decrease the reliability of the DTT as a clinical tool reflective of neurological findings both pre- and post-operatively.

In the present retrospective study, we set out to determine the correlation of DTT findings with the neurological examination findings before and after surgical resection in patients with BSCMs.

Section snippets

Patient population

Local Institutional Review Board (IRB) approved this single center study and the requirement for obtaining informed consent was waived. In compliance with retrospective study design, surgically treated patients with BSCMs were identified from the electronic medical records of the hospital between October 2012–January 2017, and pre- and post-surgical neurological examination data were extracted. Pre- and post-operative DTT findings were obtained from the radiology database.

Clinical assessment

Detailed neurological

Results

Assessment of hospital's electronic medical records for patients with BSCMs treated surgically, revealed 60 patients (26 men and 34 women) with a mean age of 40.2 ± 13.8 years (range: 9 years to 72 years). Of those 60 patients, 25 patients (9 men 16 women) with a mean age of 39.5 ± 13.9 years (range: 9 years to 68 years constituted the study group and 21 patients had both pre- and post-operative DTT and 4 patients had preoperative DTT). The most common anatomical location was pons (13 patients,

Discussion

Our results have implicated that while in some cases, deviation of the white matter tracts on DTT might be linked to significant neurological deficits, in some others, interruption of the tracts might not be associated with any neurological deficits. These results are considered to be secondary to the technically limiting blood products like hemosiderin within the CM itself, provoking susceptibility artifacts and resulting in signal losses. Previous published literature on DTT in

Funding

None.

Disclosure of interest

The authors declare that they have no competing interest.

Cited by (0)

Name of Institutional Review Board (IRB)/Ethics Committee: Yeditepe University Ethical Committee. IRB Approval Number: 758.

☆☆

All coauthors meet the criteria for authorship of the manuscript.

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