Spontaneous intracranial hypotension: Exploring the viability of non-contrast FLAIR as a substitute for contrast-enhanced T1WI in assessing pachymeningeal thickening

Sabahattin Yuzkan; Tahsin Benlice; Tevfik Guzelbey; Mehmed Fatih Yilmaz; Oner Ozbey; Merve Sam Ozdemir; Serdar Balsak; Uluc Ozkiziltan; Yavuz Altunkaynak; Ozgur Kilickesmez; Burak Kocak

doi:10.1007/s00234-024-03359-2

Spontaneous intracranial hypotension: Exploring the viability of non-contrast FLAIR as a substitute for contrast-enhanced T1WI in assessing pachymeningeal thickening

Neuroradiology. 2024 Apr 25. doi: 10.1007/s00234-024-03359-2. Online ahead of print.

Affiliations

¹ Department of Radiology, Koc University Hospital, Zeytinburnu, 34010, Istanbul, Turkey.
² Department of Radiology, University of Health Sciences, Basaksehir Cam and Sakura City Hospital, Basaksehir, 34480, Istanbul, Turkey.
³ Department of Radiology, Bezmialem Vakif University Hospital, Istanbul, Turkey.
⁴ Department of Radiology, Ege University School of Medicine, Izmir, Turkey.
⁵ Department of Neurology, University of Health Sciences, Basaksehir Cam and Sakura City Hospital, Basaksehir, 34480, Istanbul, Turkey.
⁶ Department of Radiology, University of Health Sciences, Basaksehir Cam and Sakura City Hospital, Basaksehir, 34480, Istanbul, Turkey. drburakkocak@gmail.com.

PMID: 38658472
DOI: 10.1007/s00234-024-03359-2

Abstract

Purpose: To avoid contrast administration in spontaneous intracranial hypotension (SIH), some studies suggest accepting diffuse pachymeningeal hyperintensity (DPMH) on non-contrast fluid-attenuated inversion recovery (FLAIR) as an equivalent sign to diffuse pachymeningeal enhancement (DPME) on contrast-enhanced T1WI (T1ce), despite lacking thorough performance metrics. This study aimed to comprehensively explore its feasibility.

Methods: In this single-center retrospective study, between April 2021 and November 2023, brain MRI examinations of 43 patients clinically diagnosed with SIH were assessed using 1.5 and 3.0 Tesla MRI scanners. Two radiologists independently assessed the presence or absence of DPMH on FLAIR and DPME on T1ce, with T1ce serving as a gold-standard for pachymeningeal thickening. The contribution of the subdural fluid collections to DPMH was investigated with quantitative measurements. Using Cohen's kappa statistics, interobserver agreement was assessed.

Results: In 39 out of 43 patients (90.7%), pachymeningeal thickening was observed on T1ce. FLAIR sequence produced an accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of 72.1%, 71.8%, 75.0%, 96.6%, and 21.4% respectively, for determining pachymeningeal thickening. FLAIR identified pachymeningeal thickening in 28 cases; however, among these, 21 cases (75%) revealed that the pachymeningeal hyperintense signal was influenced by subdural fluid collections. False-negative rate for FLAIR was 28.2% (11/39).

Conclusion: The lack of complete correlation between FLAIR and T1ce in identifying pachymeningeal thickening highlights the need for caution in removing contrast agent administration from the MRI protocol of SIH patients, as it reveals a major criterion (i.e., pachymeningeal enhancement) of Bern score.

Keywords: Fluid-attenuated inversion recovery (FLAIR); Gadolinium-based contrast agents; Magnetic resonance imaging; Orthostatic headache; Spontaneous intracranial hypotension.