Postmortem verification of MS cortical lesion detection with 3D DIR

Abstract

Objective: To assess the sensitivity and specificity of 3D double inversion recovery (DIR) MRI for detecting multiple sclerosis (MS) cortical lesions (CLs) using a direct postmortem MRI to histopathology comparison.Methods: Single-slab 3D DIR and 3D fluid-attenuated inversion recovery (FLAIR) images of 56 matched fresh brain samples from 14 patients with chronic MS were acquired at 1.5 T. The images of both sequences were prospectively scored for CLs in consensus by 3 experienced raters who were blinded to histopathology and clinical data. Next, CLs were identified histopathologically and were scored again on 3D DIR and 3D FLAIR (retrospective scoring). CLs were classified as intracortical or mixed gray matter (GM)-white matter lesions. Deep GM lesions were also scored. False-positive scores were noted and, from this, specificity was calculated. Results:We found a sensitivity for 3D DIR to detect MS CLs of 18%, which is 1.6-fold higher than 3D FLAIR (improves to 37% with retrospective scoring; 2.0-fold higher than 3D FLAIR). We detected mixed GM-white matter lesions with a sensitivity of 83% using 3D DIR (65% sensitivity for 3D FLAIR), which improved to 96% upon retrospective scoring (91% for 3D FLAIR). For purely intracortical lesions, 3D DIR detected more than 2-fold more than 3D FLAIR (improved to Ͼ3-fold upon retrospective scoring). The specificity of 3D DIR to MS CLs was found to be 90%. Conclusions:In this postmortem verification study, we have shown that 3D DIR is highly pathologically specific, and more sensitive to CLs than 3D FLAIR in MS. Neurology ® 2012;78:302-308 GLOSSARY BSA ϭ bovine serum albumin; CL ϭ cortical lesion; DIR ϭ double inversion recovery; FLAIR ϭ fluid-attenuated inversion recovery; GM ϭ gray matter; MS ϭ multiple sclerosis; NEX ϭ number of excitations; PBS ϭ phosphate-buffered saline; PLP ϭ proteolipid protein; TE ϭ echo time; TI ϭ inversion time; TR ϭ repetition time; WM ϭ white matter.

Ultra-High-Field MRI Visualization of Cortical Multiple Sclerosis Lesions with T2 and T2*: A Postmortem MRI and Histopathology Study

“…Previous studies at 1.5T detected only 31% 3 or 56% 16 of intracortical lesions with a T2WI sequence and 29% with a DIR sequence. 17 With a FLAIR sequence, 9%, 17 21%, 3 or 71% 18 of intracortical lesions were detected retrospectively. Compared with previous postmortem MR imaging studies at ultra-high-field (7T) strength, our T2WI and T2*WI retrospective detection rates are higher than the 67% found with R2* maps, 19 comparable with the 82% found with WM-attenuated turbo field echo, and slightly lower than the 93% detected with T2*WI.…”

The Technical and Clinical Features of 3D-FLAIR in Neuroimaging

“…For 3D-FLAIR, there are many reports regarding application to multiple sclerosis. 5,6,[42][43][44][45][46][47][48][49][50][51][52][53][54] Smaller lesions can be detected by 3D-FLAIR than by 2D-FLAIR due to thinner slices and fewer flow artifacts with 3D-FLAIR. 45,46 Excellent detection of cortical lesions by 3D-FLAIR has also been reported (Fig.…”

Clinically feasible MTR is sensitive to cortical demyelination in MS

“…4,5 The double inversion recovery sequence improves detection but does not reveal most CL. 5,6 While nonquantitative imaging features low sensitivity to CL, the sensitivity of semiquantitative and quantitative MRI is unclear. Although one ex vivo imaging study performed at 1.5 T revealed that T1 and T2 relaxation rates (not magnetization transfer ratio [MTR]) are sensitive to CL, 7 a separate study performed at 9.4 T found MTR and T2 relaxation rate (not T1) to be most sensitive.…”