Improvement of post-gadolinium contrast with magnetization transfer.

Magnetization transfer (MT) provides post-gadolinium contrast improvement through decreasing the tissue signal. Our study had two aims: to analyse the effect of MT qualitatively and quantitatively in 13 patients, and to analyse in vitro the competition between two relaxation phenomena, dipole-dipole which is characteristic of MT and proton - electron which is characteristic of gadolinium. Contrast between lesion and white matter improved from 20.6 % before MT to 65.1 % after MT, enabling new lesions to be detected in two patients. The improvement was due mainly to the proton - electron effect of gadolinium rather than the dipole relaxation of MT. These results are in agreement with those in the literature. The existence of spontaneous high-signal induced by MT in the absence of gadolinium indicates that it is preferable to perform an MT sequence before and after administration of gadolinium.