Combined analysis of DIR and PSIR images discloses a high cortical lesion load in multiple sclerosis cortex (P4.004)

Objective. To analyze CL frequency and type in MS patients having different disease duration and disability by combining the information obtained by DIR and PSIR. Background. Studies with double inversion recovery (DIR) have disclosed an association between cortical lesion (CL) and cognitive and physical disability in multiple sclerosis (MS). However, DIR detects less then 20[percnt] of pathologically confirmed CL. Recently, phase-sensitive inversion recovery (PSIR) was demonstrated to be more sensitive and accurate that DIR in CL detection and classification. Patients and Methods. 40 patients (10 clinically isolated syndrome (CIS)/earlyRRMS (eRRMS), 24 RRMS, 6 SPMS) were included in the study. DIR and PSIR images were acquired by 3T MRI and identified by consensus of 3 examiners. PSIR and DIR images were jointly used to classify lesions as purely intracortical (IC), mixed grey-white matter or leukocortical (LC) and juxtacortical (JC). Results. PSIR disclosed CL in 100[percnt] of the patients, independently of DD and EDSS score, and was capable of identifying about four/five times (455.5[percnt], p<0.00001) more lesions, especially IC (mean numbers: 36.5 in CIS/eRRMS, 45.0 in RRMS and 52.3 in SPMS) and LC (mean numbers: 10.9 in CIS/eRRMS, 20.1 in RRMS and 25.3 in SPMS), compared to DIR (p<0.00001). In SPMS, up to ten or more lesions could be identified in a single brain axial image and more than 100 lesions could be scored in the entire brain. Artefacts were better identified by the comparison of the two sequences. Discussion. Our study confirms the higher accuracy and sensitivity of PSIR in disclosing and classifying CL. The presence of CL in all CIS patient further points out the relevance of cortical pathology in MS. DIR/PSIR images may be useful when a diagnosis of MS is suspected but not confirmed and may allow a better stratification of the patients for clinical studies. Disclosure: Dr. Favaretto has nothing to disclose. Dr. Poggiali has nothing to disclose. Dr. Lazzarotto has nothing to disclose. Dr. Rolma has nothing to disclose. Dr. Causin has nothing to disclose. Dr. Rinaldi has nothing to disclose. Dr. Perini has nothing to disclose. Dr. Gallo has received personal compensations for activities with Biogen Idec, Novartis, Merk Serono, Bayer Schering, and Genzyme as a speaker and/or consultant.