Human brain infarcts: Gd-DTPA-enhanced MR imaging

During Food and Drug Administration phase II and III clinical trials for gadolinium DTPA, the paramagnetic agent was used to study 11 patients with 20 subacute and chronic cerebral infarcts. Five patients had numerous periventricular and deep white-matter lesions, probably due to chronic ischemic disease. Magnetic resonance (MR) imaging was performed 4-30 days after the ictus, preceded by computed tomography (CT) in all but one case. In most cases, the nonenhanced spin-echo (SE) images, obtained at 500-msec repetition times and 30-msec echo times, failed to demonstrate the infarct, and in general the gadolinium-enhanced SE 500/30 images matched the contrast material-enhanced CT scans in pattern. Periventricular lesions and small, deep, white-matter infarcts that were chronic and asymptomatic were not enhanced by gadolinium MR. However, three small, symptomatic capsular and brain-stem infarcts showed definite enhancement. Usually the enhancement was visible at 3 minutes, increasing to a peak at 30 minutes. At 55 minutes, the enhancement increased in the medium-aged infarcts (8-14 days), while it decreased in the late infarcts (15-30 days). The T2 relaxation time-weighted pulse sequences were most sensitive for demonstrating all infarcts, but without the aid of a contrast agent, they were frequently poor in specificity.