FLAIR* for the non-invasive histological diagnosis of multiple sclerosis (S29.003)

Objectives: To explore whether FLAIR* is superior to current MRI criteria for a diagnosis of MS using MRI datasets acquired at a single time point and a standard field strength (3T). Background: Current MRI criteria to support the diagnosis of MS are based on dissemination in time (DIT) and space (DIS) of CNS white matter lesions (WML). Application of these criteria may not be straightforward thereby delaying diagnosis. The 9central vein9 (CV) in WML, a characteristic histological feature of MS, has become accessible in vivo using T2* based techniques. FLAIR* is a post-processing algorithm combining T2* with FLAIR, an established sequence for WML detection. Methods: Seventeen people with relapsing MS (pwRMS; 11 men; age 39±8.6 years; disease duration 7± 5.3 years) underwent MRI. FLAIR* images were constructed using MIPAV (www.mipav.cit.nih.gov) and JIST (www.nitrc.org/projects/jist/) image processing software. FLAIR* images were assessed by two observers independently. WML >3mm were identified and the presence of a central hypointensity suggestive of a CV (CV sign; CVS) recorded. A proportion of >40[percnt] CVS positive WML was considered diagnostic for MS. Diagnoses based on a proportion of >40[percnt] CVS+ WML were compared with diagnoses made using DIS/DIT criteria applied at a single time point on these datasets. Results: In 17 pwRMS, 239 WML were identified. Inter-observer agreement for the presence of the CVS was good (κ = 0.63). 88[percnt] of WML were CVS positive. All pwRMS met the diagnostic criterion (CVS+ in >40[percnt] of WML). All pwRMS met current MRI DIS criteria, but only 1/17 met DIT criteria. Conclusions: FLAIR* enables detection of a characteristic histological feature of MS WML, the CV, in vivo. Prospective studies in people with a clinically isolated syndrome are needed to confirm the diagnostic value of the CVS detected using FLAIR*. Disclosure: Dr. Campion has nothing to disclose. Dr. Smith has nothing to disclose. Dr. Turner has nothing to disclose. Dr. Altmann has received personal compensation for activities with Merck & Co., Inc. Dr. Sati has nothing to disclose. Dr. Evanson has nothing to disclose. Dr. George has nothing to disclose. Dr. Miquel has nothing to disclose. Dr. Reich has nothing to disclose. Dr. Schmierer has received personal compensation for activities with Sanofi-Aventis Pharmaceuticals Inc., Novartis, and Merck Serono as a speaker.