T1 dark blood technique increases sensitivity for detection of contrast enhancing lesion in MS

Background: In multiple sclerosis (MS) the sensitivity for detection of contrast enhancing lesions (CEL) in T1w scans is essential for diagnostics and therapy decisions. The purpose of our study was to evaluate the sensitivity of T1mprage scans in comparison to T1 dark blood technique (T1-DB) for CEL in MS. Methods: 21 MS patients received 3 T MRI with T2-weighted imaging and T1mprage pre (T1nat) and post gadolinium (T1-GD) sequences. After GD application, the T1-DB scan was performed prior to T1-GD. From pre and post T1mprage GD scans, subtraction images (SUB) were calculated. The number of CEL was determined separately on T1-GD and T1-DB by 2 raters independently. Lesions only detected on T1-DB scans were then verified on SUB images. Only lesions detected by both raters were included into further analysis. Results: 23/21 T1-GD lesions were detected by rater 1/2. In comparison, 8/7 more lesions were detected on T1-DB, all of these lesions could be verified on SUB images. In retrospective evaluation, CEL only detected in T1-DB were lesions that became hypo- or isointense on T1-GD in comparison to T1nat. On SUB images, 1 false positive lesion was detected, which could not be verified on T1-GD or T1-DB and was accounted to movement artifacts. In 13 patients, no CEL was detected in any of the sequences. Conclusion: The application of T1-DB technique increases the sensitivity for CEL in MS, especially for those lesions that show a subtle increase in intensity after GD application but remain hypo- or isointense to surrounding tissue.