3D MPRAGE EVALUATION OF LESIONS IN THE POSTERIOR CRANIAL FOSSA

Standard spin-echo images of the posterior cranial fossa are usually i mpaired by pulsation artifacts. We evaluated a heavily T-1 weighted MP RAGE sequence (TR/TE/alpha/TI = 10/4/10-15 degrees/200-330) for detect ion of intracerebral lesions in the posterior fossa in 11 patients. Ov erall quality of the MPRAGE images was superior due to the lack of pul sation artifacts, high S/N and excellent gray-white matter contrast. L esion detection was better in one patient, equal in six and inferior i n four patients compared to SE technique. A cerebellar metastasis (8 m m) in one patient was completely blurred from pulsation artifacts on t he SE images, Whereas multiple small lesions (less than or equal to 4 mm) with discrete contrast enhancement were missed on the MPRAGE image s in three patients, We conclude, that the MPRAGE sequence yields high quality images with isotropic spatial resolution in a reasonable time . But MPRAGE with these parameters can not replace standard SE images in screening the posterior fossa, because of a decreased sensitivity i n the detection of small contrast-enhancing lesions.