Increased subpial cortical lesion detection at 3 tesla using Inversion Recovery Susceptibility Weighted Imaging with Enhanced T2 Weighting (IR-SWIET).

BACKGROUND

Multiple sclerosis subpial cortical lesions are prevalent and associated with disability but difficult to detect on MRI. Inversion recovery susceptibility weighted imaging with enhanced T 2 weighting (IR-SWIET) and T 1 /T 2 ratio imaging have been proposed for cortical lesion detection on 3 tesla (T) MRI.

OBJECTIVES

To assess cortical lesion detection using IR-SWIET and T 1 /T 2 ratio imaging.

METHODS

Cortical lesions were identified in 20 persons with MS (pwMS) independently on six image sets: T 1 weighted (w) magnetization prepared 2 rapid acquisition gradient echoes (MP2RAGE) + T 2 w fluid attenuated inversion recovery (FLAIR) alone or with T 1 /T 2 , IR-SWIET single acquisition (×1), average of two (×2) or median of four (×4) acquisitions, or denoised single acquisition (IR-SWIET×1DN). In 10 additional pwMS with 7T-based cortical lesion segmentations, lesions were identified on MP2RAGE + FLAIR + IR-SWIET×1DN.

RESULTS

Median subpial lesions identified on MP2RAGE + FLAIR was 0 (interquartile range (IQR) 2) vs 0 with T 1 /T 2 (IQR 1, p=0.07), 1 with IR-SWIET×1 (IQR 6, p=0.42), 5 with IR-SWIET×2 (IQR 5, p=0.008), 4 with IR-SWIET×4 (IQR 6, p=0.008), and 4 with IR-SWIET×1DN (IQR 6, p=0.008). Versus 7T, IR-SWIET×1DN detected subpial lesions with similar sensitivity to IR-SWIET×2.

CONCLUSIONS

IR-SWIET, but not T 1 /T 2 , improves subpial cortical lesion detection. Denoising may be an efficient and sensitive alternative to multi-acquisition averaging.