Assessment of Inter-Reader Reliability of Fazekas Scoring on Magnetic Resonance Imaging of the Brain in Adult Patients with Sickle Cell Disease

Abstract

Background/Objectives: Cerebral white matter disease is a common finding in patients with sickle cell that has been linked to cognitive impairment. However, there is no standardized approach for quantification of the cerebral disease burden. The Fazekas score is widely used to quantify the burden of white matter disease in chronic small vessel disease. However, its utility in sickle cell disease, specifically the inter-rater variability, has not been established. Methods: A patient cohort was compiled for the purpose of a research ethics board (REB)-approved retrospective study of adult patients with sickle cell disease, each of whom underwent MRI/MRA between the years 2017 and 2019. A total of 90 such patients were captured. All MRI/MRA studies were performed on three Tesla MRIs. Two independent neuroradiologists assessed the axial FLAIR MRI brain sequence (see image 1) for each of the 90 patients, with the sole focus of assigning a Fazekas score (0-3) to each study as a means of quantifying the burden of ischemic white matter lesions. The neuroradiologists were blinded to the scoring assigned by their counterpart and to the clinical information. After the initial assessment was completed, studies with discrepant Fazekas scores were documented and discussed by both readers. A consensus Fazekas score was then assigned to each of these studies. Results: Cohen's weighted kappa was used as a measure of agreement between readers. The expected agreement was 74.65%, with an observed agreement of 94.44% between readers, with a kappa of 0.7808. Conclusions: We conclude on the basis of our study that there is good inter-reader reliability of Fazekas scoring on axial FLAIR MRI brain sequence in patients with sickle cell disease. The Fazekas is a promising measure that could easily be integrated in systematic evaluation of cerebrovascular lesions of adults with sickle cell disease.

Keywords: Fazekas scoring tool; magnetic resonance imaging; sickle cell disease; white matter disease.

Figure 1

Multiple axial (Ax) T2-FLAIR MR images (A–H) depicting Fazekas scores 0–3. (A,B): demonstrate Fazekas 0, with no evidence of WMD; (C,D): show rare focal WM hyperintensities (white arrows), Fazekas 1; (E,F): show beginning of confluence of WM hyperintensities (white arrows), Fazekas 2; (G,H): show diffuse involvement of periventricular WM (white arrows), Fazekas 3.

Figure 2

Ax T2-FLAIR MR images demonstrate hazy T2-FLAIR signal hyperintensity (arrows) in the posterior periventricular hyperintensity, presumed to be related to technical differences or technical artifacts. In total, 9 such cases were initially classified as Fazekas 0 and 2, respectively, by each of the readers, with consensus opinion of Fazekas 0.