MRI of lumbar and sacral plexus nerve sheath tumours.

Seven patients with peripheral nerve sheath tumours affecting the lumbo-sacral plexus were examined with MR imaging utilizing a 1.5T magnet and spin echo pulse sequences. The majority of tumours were homogeneous in signal intensity and isointense with adjacent muscle on T1 weighted images and showed markedly increased signal intensity on T2 weighted images with central areas of relatively low signal intensity. An attempt to obtain a pathological correlation with the areas of low signal on T2 weighted images was unsuccessful. The use of Gadolinium DTPA in one patient resulted in irregular enhancement of both a neurogenic sarcoma and smaller neurofibromas. The multiplanar imaging capabilities, high soft tissue contrast, non-invasiveness, lack of ionizing radiation and the characteristic appearance of neural tumours makes MR ideal for imaging these lesions.