3D MPRAGE EVALUATION OF LESIONS IN THE POSTERIOR CRANIAL FOSSA

Standard spin-echo images of the posterior cranial fossa are usually impaired by pulsation artifacts. We evaluated a heavily T-1 weighted MPRAGE sequence (TR/TE/alpha/TI = 10/4/10-15 degrees/200-330) for detection of intracerebral lesions in the posterior fossa in 11 patients. Overall quality of the MPRAGE images was superior due to the lack of pulsation artifacts, high S/N and excellent gray-white matter contrast. Lesion detection was better in one patient, equal in six and inferior in four patients compared to SE technique. A cerebellar metastasis (8 mm) in one patient was completely blurred from pulsation artifacts on the SE images, Whereas multiple small lesions (less than or equal to 4 mm) with discrete contrast enhancement were missed on the MPRAGE images 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 in the detection of small contrast-enhancing lesions.