Stereotactic radiosurgery has been widely applied to treat cerebral arteriovenous malformations (AVMs), and various relevant studies have been reported to date. Recently, however, many new facts have been clarified by our up-to-date long-term follow-up study. Here we present our experience in Stereotactic radiosurgery using a gamma knife to treat these lesions. The hemorrhagic risk from AVMs was significantly reduced even during the latency period and then was further reduced after obliteration. Advancements in imaging technique realized significantly less frequent complications. However, a small risk of hemorrhage and delayed cyst formation still remained after obliteration, and therefore, even angiographic obliteration, which is one the treatment goals, did not necessarily mean an ultimate cure for AVMs. Therefore, long-term follow-up even after obliteration is essential. At the same time, radiosurgery continues to be an effective treatment in small AVMs with high surgical risks.

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There has been a little evidence for glioma therapy since it is rare and intractable disease. A hundred andthree new adjuvant therapy individualized by the results of reverse-transcription polymerase chain-reaction (RT-PCR) for O^6-methylguanin DNA methyltransferase (MGMT) has been used to treat 90 patients with gliomas (12 low grade gliomas, 30 Grade III gliomas, 42 glioblastomas, and 6 medulloblastomas) since April, 1997. Immediately after the operation, the mRNA expression for MGMT was investigated in 51 fresh samples of gliomas byconventional RT-PCR, in 12 by quantitative RT-PCR, and 40 by real-time RT-PCR. In sixty-eight therapies 1-(4-amino-2-methyl-5-pyrimidinyl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) were usedbecause relative low expression of MGMTmRNA, and 35 therapies consisted of platinum compounds since thetumors had had relative high MGMT expression. In this individual adjuvant therapy (IAT), no significant differencewas observed in the effect of ACNU-treated group and platinum-treated group. Forty-nine of 92 evaluable therapies had a partial or complete response (53.3% response rate). Two-year survival rate of 42 glioblastoma multiforme was 51.1%. In recent 20 IAT for primary anaplastic astrocytoma and glioblastoma with age over 3 yo under70 yo, with Karnofsky's performance status over 50, treated with either ACNU-vincristin-interferon β-radiation or cis-platinum-etoposide-interferon β-radiation decided by real-time RT-PCR, response rate was 60.0%.Although IAT based on RT-PCR seemed to be more effective than conventional therapies for malignant gliomas,the evaluation of IAT is difficult because of its heterogeneity of treatment protocol. A prospective randomized controlled trial was needed to obtain a high-level evidence of IAT.

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Introduction : The mechanism of reduction of cerebral circulation in the early phase of aneurysmal subarach noid hemorrhage (SAH) has not yet been clarified. Previous studies have variously indicated that cerebral blood flow (CBF) reduction may be due to cerebral vasospasm, an elevation in intracranial pressure (ICP), constriction of intraparenchymal arterioles, or metabolic reduction. The aim of this study is to investigate the relationship between cerebral circulation and oxygen metabolism. Methods : In 36 patients with aneurysmal SAH, the values of mean cerebral blood flow (mCBF), cerebral metabolic rate of oxygen (CMRO_2) and oxygen extraction fraction (OEF) were measured by using single photon emission computed tomography (SPECT) with arterial blood drawing and oxygen saturation of internal jugular bulb blood (SjO_2) in the acute stage (l-3 days after onset) and the spasm stage (7-10 days after onset). The patients in our study were selected by using the following criteria : (a) no history of cerebrovascular or cardiopulmonary diseases ; (b) under the age of 70 ; (c) the ruptured aneurysm was treated by clipping or coil embolization within 72 hours after onset ; (d) no symptoms of cerebral vasospasm ; (e) no signs of cerebral ischemic change on CT scans. These patients were divided into 2 groups according to the WFNS grading classification ; the mild group (Grades I and II) consisted of 27 cases and the severe group (Grade IV) consisted of 9 cases. We studied differences in mCBF, CMRO_2, and OEF between the mild group and severe group. Results : In the mild group, mCBF, CMRO_2, and OEF were significantly higher than in the severe group during both the acute and the spasm stage. Also mCBF showed a direct correlation with CMRO_2. Discussion and conclusion : All the patients were kept under the following conditions ' (a) the bed was positioned so that the upper body was raised at an angle at 30°; (b) blood pressure was maintained at 130-150 mmHg and PaCO_2 of arterial blood was maintained at 35-40 mmHg ; (c) ICP was controlled with external ventricular drainage, and we ruled out cerebral vasospasm with cranial angiography on admission. Therefore, the cause of the reduction in CBF is not related to cerebral perfusion pressure or cerebral vasospasm. The correlation between mCBF and CMRO_2 showed that the reduction in CBF is due to depression of cerebral oxygen metabolism in the early phase of aneurysmal SAH in patients without symptoms of vasospasm.

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A case of cerebellar glioblastoma with mild intratumoral hemorrhage is reported. A 56-year-old woman was admitted to our hospital with vertigo, nausea and vomiting. On admission, CT scan and MRI revealed a cerebellar tumor with mild intratumoral hemorrhage. She underwent gross total removal of cerebellar tumor through bilateral suboccipital craniectomy. Pathological diagnosis was glioblastoma. After the surgery, radiation therapy (60 Gy) and chemotherapy (ACNU & IFN-β) were performed. She was discharged with mild cerebellar ataxia. Glioblastoma multiforme is a rare tumor of the cerebellum. Moreover, it is ever rare to show intratumoral hemorrhage. We discuss the clinical characteristics with a review of the literature.

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A 36-year-old woman complained of a sudden headache, right hemiparesis, and visual disturbances. A CT scan showed a subarachnoid hemorrhage and a round, high-density mass near the left crural cistern. The initial cerebral angiogram revealed a large aneurysm in the left P2-3 segment of the posterior cerebral artery (PCA). The patient was treated conservatively. A MRI, taken 11 days after the onset, showed a partially thrombosed large aneurysm. The second angiogram, taken one month after the onset, showed complete occlusion of the aneurysm without visualization of the left distal PCA. The third angiogram, taken two months after the onset, showed recanalization of the distal PCA, and 3D-CT angiogram at two and a half months after the onset showed reappearance of the neck of the aneurysm. To prevent the aneurysm from rerupturing, parent artery occlusion (PAO) of the aneurysm was performed using endovascular surgery. Both the aneurysm and the P2-3 segment of the left PCA were obliterated. However, since collateral circulation through the parietal branches of the middle cerebral artery filled the distal PCA, no severe complications appeared following PAO. The patient was discharged with slight right hemiparesis, but no visual disturbances. Only a few cases have been reported involving the spontaneous disappearance of aneurysms on cerebral angiograms. Even rarer are cases involving the reappearance of aneurysms. In the past, surgical clipping was indicated for the treatment of P2-3 segment aneurysms. Recently, however, PAO has been performed using endovascular techniques. It has been reported PAO using endovascular techniques is a relatively safe treatment for P2-3 segment aneurysms, because the rich collateral blood supply to the PCA provides good ischemic stress tolerance.

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A rare case of traumatic carotid-cavernous fistula (CCF) with unilateral double fistula in a 67-year-old male is presented. An angiogram demonstrated double arterio-venous fistula in the dorsomedial wall of C4 and the ventrolateral wall of C5 of the left internal carotid artery. Both fistulae were successfully obliterated with detachable balloon and platinum coils. Direct laceration of the different segment of the internal carotid artery was a possible cause of the double arterio-venous fistula. The mechanisms for formation of double arterio-venous fistula were discussed.

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Vertebral hemangioma is a common benign lesion of the spine that often is asymptomatic, typically being discovered incidentally during evaluation of neck or back pain. Symptomatic vertebral hemangiomas are rare. Here we report two vertebral hemangiomas associated with neurologic deficits. The first patient was a 45-year-old woman presenting with back pain and weakness of both lower extremities. Radiographs revealed a compression fracture of the T12 vertebral body. Resection of the tumor was undertaken by a right retropleural retroperitoneal approach, but removal was only partial because of uncontrollable intraoperative bleeding. A second operation performed following an embolization procedure accomplished gross total removal. The second patient was a 47-year-old man who presented with numbness of both lower extremities. Imaging disclosed a vertebral hemangioma at T5. Preoperative angiography and embolization were performed, followed by gross total removal via a transpleural approach. We concluded that preoperative arterial embolization is highly benefical in reducing blood loss during resection of vertebral hemangiomas.

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We report a case of anomalous vertebral arteries with compression of the upper cervical cord. A 58-year-old man complained of a sharp and stabbing pain in the left suboccipital region and tingling sensation in his left upper limb and shoulder. Neurological examination on admission showed no definite abnormality. Cervical MRI showed a flow void in the spinal canal at the level of the atlas. Vertebral angiography and 3D-CT angiography showed that the bilateral vertebral arteries had penetrated the dura mater below the posterior arch of the atlas in the atolantoaxial interlaminar space. We diagnosed the symptoms as due to the anomalous vertebral arteries. Cl and C2 laminectomy was performed in the prone position. Postoperative course was uneventful, but the same pain occurred one year later. Three and a half years after the operation, the degree and frequency of the pain was one third of the primary pain. A review of the literature and the findings from our case revealed that transposition of the anomalous vertebral arteries by surgery should be performed for complete relief from the symptoms.

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