The impact of image contrast, resolution and reader expertise on black hole identification in Multiple Sclerosis.

Abstract

In the neuroradiological work-up of Multiple Sclerosis (MS), the detection of "black holes" (BH) represent an information of undeniable importance. Nevertheless, different sequences can be used in clinical practice to evaluate BH in MS. Aim of this study was to investigate the possible impact of different sequences, resolutions, and levels of expertise on the intra- and inter-rater reliability identification of BH in MS. Brain MRI scans of 85 MS patients (M/F = 22/63; mean age = 36.0 ± 10.2years) were evaluated in this prospective single-center study. The acquisition protocol included a 3mm SE-T1w sequence, a 1mm 3D-GrE-T1w sequence from which a resliced 3mm sequence was also obtained. Images were evaluated independently by two readers of different expertise at baseline and after a wash-out period of 30days. The intraclass correlation coefficient (ICC) was calculated as an index of intra and inter-reader reliability. For both readers, the intra-reader ICC analysis showed that the 3mm SE-T1w and 3mm resliced GrE-T1w images achieved an excellent performance (both with an ICC ≥ 0.95), while 1mm 3D-GrE-T1w scans achieved a moderate one (ICC < 0.90). The inter-reader analysis showed that each of the three sequences achieved a moderate performance (all ICCs < 0.90). The 1mm 3D-GrE-T1w sequence seems to be prone to a greater intra-reader variability compared to the 3mm SE-T1w, with this effect being driven by the higher spatial resolution of the first sequence. To ensure reliability levels comparable with the standard SE-T1w in BH count, an assessment on a 3mm resliced GrE-T1w sequence should be recommended.