Tissue characterisation of intracranial tumours: the value of magnetisation transfer and conventional MRI.

We performed MRI on 85 patients with intracranial tumours to evaluate quantitative analysis in tumour characterisation. Signal intensities were measured on standard T2- and T1-weighted images, Gd-enhanced T1-weighted images and magnetisation transfer (MT) images. Statistically significant differences between tumour types were observed, but overlapping reduces their value. T2-weighted imaging was superior to T1-weighted imaging for tumour characterisation. Quantification of Gd enhancement was useful in the diagnosis of pituitary adenomas and haemangioblastomas, but of minor importance in other tumours, because of large nonspecific variation. The contribution of MT contrast to tumour characterisation resembled that of T2 contrast. However, MT imaging was superior to other sequences in the classification of intra-axial tumours. Low-grade astrocytomas, haemangioblastomas and craniopharyngiomas could be differentiated from other tumours on the basis of MT contrast. Reliable discrimination between meningiomas, high-grade astrocytomas and metastases was not possible by any of the methods.