Jun Onda

MRI of intracranial germ cell tumors

We reviewed MRI findings in proven intracranial germ cell tumours in 22 cases, 12 of whom received Gd-DTPA. On T1-weighted images, the signal intensity of the tumour parenchyma was moderately low in 19 cases and isointense in 3; on T2-weighted images, it was high in all cases. Regions of different intensity thought to be cysts were found in 17 (77%): 7 of 12 patients with germinoma (58%) and in all other cases. Of the 13 patients with pineal lesions T1-weighted sagittal images showed the aqueduct to be obstructed in 5, stenotic in 7 and normal in 1. Strong contrast enhancement was observed in all 12 cases. Of the 14 patients with suprasellar lesions, 5 were found to have an intrasellar extension, and in 3 of these, the normal pituitary gland, which could be distinguished from the tumour, was displaced anteriorly. Ten patients (45%) had multiple lesions.

Surface anatomy scanning (SAS) in intracranial tumours: comparison with surgical findings

We evaluated the usefulness of surface anatomy scanning (SAS) in intracranial tumours, comparing it with surgical findings. We examined 31 patients with brain tumours preoperatively. The tumours included 16 meningiomas, 8 gliomas, 4 metastases and 3 others. SAS clearly demonstrated the tumours, allowing them to be distinguished from the structures of the brain surface, including oedema, except in cases of metastasis. SAS clearly demonstrated large cortical veins. SAS is useful for three-dimensional delineation of the brain surface before surgery.

MRI of pituitary adenomas: the position of the normal pituitary gland

The position of the normal pituitary gland, assessed using gadolinium-enhanced MRI was compared with the position found at surgery for pituitary adenoma in 25 patients. The tumours were five microadenomas and 20 macroadenomas. Using T1-weighted imaging, the anterior lobe could be differentiated on the sagittal image in five patients (20%) and on the coronal image in four (16%). The high intensity of the posterior lobe could be differentiated using T1-weighted sagittal imaging in 13 patients (52%). The normal pituitary gland, which enhanced more strongly than tumour, could be differentiated using Gd-DTPA-enhanced MRI on the sagittal images in 22 cases (88%) and on the coronal image in 17 (68%). In seven patients, the normal pituitary gland surrounded the tumour; it was displaced superiorly in 14 cases and superioposterorly in two but in no case was it displaced anteriorly or downwards.