POTENTIAL FOR INCREASING CONSPICUOUSNESS OF SHORT-T1 LESIONS IN THE BRAIN USING MAGNETIZATION-TRANSFER IMAGING

We investigated the feasibility of using T1-weighted magnetisation tra nsfer sequences to generate tissue contrast and increase the conspicui ty of short-T1 areas within the brain. We imaged two normal volunteers with and without saturating off-resonance radiofrequency irradiation at a range of repetition times (TR 200-760 ms). T1 values and magnetis ation transfer ratios for white matter and deep grey matter were calcu lated. We studied eight patients with intracranial lesions showing sho rt-T1 areas, using mildly T1-weighted sequences with and without magne tisation transfer contrast. Lesion numbers, areas and signal intensiti es were measured and lesion-to-background contrast was calculated. Com parison was made with conventional T1-weighted spin-echo images. In th e normal volunteers, contrast between the thalamus, caudate and lentif orm nuclei and white matter showed striking visual differences, with m agnetisation transfer weighting, with decreasing TR. In all patients, short-T1 lesions were seen more clearly on magnetisation transfer-weig hted images, with significant increase in lesion number, area and cont rast, when compared with conventional T1-weighted scans.