Single-shot echo-planar imaging of multiple sclerosis: effects of varying echo time

Our aim was to determine the relative merits of short and long echo times ( TE) with single-shot echo-planar imaging for imaging cerebral lesions such as multiple sclerosis, We examined seven patients with clinically definite multiple sclerosis were imaged at 1.5 T. Patients were scanned with spin-ec ho, single-shot echo-planar imaging, using TEs of 45, 75, 105, and 135 ms. Region of interest (ROI) measurements were performed on 36 lesions at or ab ove the level of the corona radiata. The mean image contrast (IC) was highe st (231.1) for a TE of 45 ms, followed by 75 ms (218.9), 105 ms (217.9), an d 135 ms (191.6). When mean contrast-to-noise ratios (CIN) were compared, t he value was again highest (29.7) for TE 45 ms, followed by 75 ms (28.9), 1 05 ms (28.5), and 135 ms (26.3). In a lesion-by-lesion comparison, TE 45 ms had the highest IC and CIN in the largest number of cases (50 % and 47.2 % , respectively). IC and CIN for TE 45 ms were superior to those of 75 ms in 64 % and 58 %, respectively. These results support the use of relatively s hort TEs for single-shot echo-planar imaging in the setting of cerebral les ions such as multiple sclerosis.