Magnetic resonance imaging in small lesions of the central nervous system. Improvement by gadolinium-DTPA.

T1 values and T2 values (CPGM-sequence) of neurinomas and meningiomas were determined, and showed values close to those of white and grey matter or, in regressive cystic neurinomas, near the cerebrospinal fluid (CSF). By this overlapping in relaxation times, as well as by crossover and boundary effects, small tumors may be obscured. The application of gadolinium-DTPA allows easier identification even of small lesions, by the high contrast achieved on the T1 weighted imaging sequences, which also avoids crossover and boundary effects with the adjacent parenchyma and CSF. This is demonstrated in intrameatal acoustic neurinomas, vascular tumors, small and en plaque growing meningiomas, and tumors of the spinal canal.