[Correlation of serial MRI and histological findings following intra-tumor local chemotherapy for malignant brain tumor].

Serial magnetic resonance imaging (MRI) studies on patients with malignant brain tumor after postoperative adjuvant therapy have been rarely reported. Leukoencephalopathy after such treatment is a well-known serious adverse effect, which we studied by serial MRI after postoperative adjuvant therapy in 15 patients with malignant brain tumors (anaplastic glioma 6, astrocytoma Grade III 5, astrocytoma Grade II 2, and metastatic brain tumor 2) (Table 1). All patients were examined by MRI, more than twice postoperatively. Adjuvant therapy was as follows: adriamycin (ADM) (0.5 mg) was injected through Ommaya reservoir into the tumor bed at the craniotomy. The usual total dose of ADM was 5.0 mg. In three of 15 patients, local methotrexate chemotherapy was added. Fourteen patients received a course of local irradiation 58 Gy on average combined with local ADM chemotherapy. Histological findings of three autopsy cases and ten reoperated ones were correlated with the serial MRI. Consecutive MRI were examined one and three months after adjuvant therapy. The results were as follows: One month after adjuvant therapy, thin and high signal intensity areas could be seen in the marginal zone of the tumor cavity on the gadolinium-enhanced T1-weighted MRI. High signal intensity areas could also be seen in the operative cavity on the T1-weighted MRI, which were suspected to be residual hematomas. In one patient, a high, diffuse and widespread signal area could be seen on T2-weighted MRI, suggesting leukoencephalopathy. Three months after adjuvant therapy, a high thick signal intensity area could be seen in the marginal zone of the tumor cavity and along the route of the Ommaya tube on the gadolinium-enhanced T1-weighted MRI, but there was no mass effect in these space taking lesions. In five cases, a low signal intensity area could be seen in the porencephalic cystic lesion, in one of which septum formation of cystic cavity was detected on the gadolinium-enhanced T1-weighted MRI. Morphologically, there was massive coagulation necrosis in the tumor cavity, but in the vicinity of the cystic wall abundant fibrous connective tissue was found to correspond with the high and thick signal intensity area on the above-mentioned gadolinium-enhanced T1-weighted MRI.(ABSTRACT TRUNCATED AT 400 WORDS)