CORTICAL PLAQUES VISUALIZED BY FLUID-ATTENUATED INVERSION-RECOVERY IMAGING IN RELAPSING MULTIPLE-SCLEROSIS

Fluid-attenuated inversion recovery (FLAIR) imaging with prolonged inv ersion times allows generation of highly T2-weighted images of the bra in with suppression of cerebrospinal fluid signal. Such sequences resu lt in high lesion contrast and allow visualisation of abnormalities no t seen with conventional T2-weighted spin-echo sequences. We used FLAI R sequences, proton density (PD) and standard T2-weighted images to ex amine lesion number and distribution in ten patients with clinically d efinite relapsing multiple sclerosis (MS), We also studied the extent and distribution of blood-brain-barrier breakdown by gadolinium-enhanc ed T1-weighted images. FLAIR sequences proved feasible both in terms o f acquisition time and image quality using a 0.5 T imager, FLAIR imagi ng allowed identification of 45% more high-signal lesions than T2-weig hted or PD images in the 10 patients, In particular, 60% more lesions within the cortex and at the grey-white interface were identified, Cor tical lesions, none of which enhanced following gadolinium-DTPA inject ion, were present in seven of the ten patients studied, Of all lesions identified, 8% were cortical. FLAIR sequences are more sensitive to c ortical and subcortical lesions in patients with active demyelination.