脳腫瘍に対するimage guided stereotactic biopsy71例の経験

Image Guided Stereotactic Biopsy for Brain Tumors:Experience of 71 cases

I．はじめに

　近年，MRI等の画像診断技術の進歩により，脳深部の微小な腫瘍も容易に発見可能となり，またその診断も正確となっている．しかし画像及び臨床所見のみでは診断に苦慮する例も少なくない^2,4）．特に問題となるのは腫瘍の占拠部位，広がり，また患者の状態等により，開頭による組織診断を選択し難い場合である．その際の治療方針について議論のあるところとなる^9）．脳腫瘍を治療する際，また予後を推定する意味でも，組織診断が重要であることは周知の事実である，われわれはそのような病例に対して，積極的にCTまたはMRI誘導による定位脳手術による腫瘍生検を行い診断を確定することとしている．今回その具体的手技，成績等について若干の文献的考察を加え報告する．

Despite advances in the neuroimaging of the brain, an accurate diagnosis of intrinsic lesion of the brainrequires tissue sampling and histological verification.

Seventy-one patients with intraparenchymal lesion of the brain underwent CT or MRI-directed stereotactic biopsy at Okayama University Hospital between June, 1987 and March, 1995. There were 32 men and 39 women whose ages ranged between 7 and 78 years (mean 46.1 years). All patients underwent preoperative cerebral angiography, high resolution contrast en-hanced CT and MRI. The lesions were located in the hemisphere in 40 cases, the thalamus or basal ganglia in 14, the midline (corpus callosum or ventricle) in 11, the pineal region in 4, the suprasellar in one and multi-ple sites in one. A Brown-Roberts-Wells (BRW) CT-directed stereotactic system was used for biopsy under CT guidance. For MRI-directed biopsies a prototype modification of the BRW frame was employed. Target localization was performed using either CT or MRI. Usually one or two targets within the lesion were chosen and target coordinates were calculated using the CT or MRI scan soft ware. Positive diagnosis was obtained in 67 cases and the accuracy of the histologic-al diagnosis was 94.4%. There were 53 gliomas, 4 metastasis, 5 germinomas, 3 malignant lymphomas, one pineoblastoma, one infarction and 4 negative biopsies. Bleeding as a complication due to stereotactic interven-tion occurred in one patient (1.4%). To patients with potentially inoperable lesions or lesions which might be best treated by chemotherapy or irradiation, modern techniques of neurosurgery now offer the option of pre-cise stereotactic biopsy through small twist-drill burr holes as opposed to open biopsy. Modern stereotactic biopsy is a minimally invasive but highly accurate means for obtaining this information.