The usefulness of magnetic resonance angiography (MRA) and three-dimensional computed tomography angiography (3D-CTA) for detecting middle cerebral artery (MCA) stenosis was evaluated by comparison with digital subtraction angiography (DSA) in 37 patients with 40 stenotic lesions of the MCA. The maximum intensity projection (MIP) of 3D-CTA was also performed for 25 of the 40 lesions. MRA showed the same degree of stenosis as DSA in 6 of the 40 lesions (15%) and overestimated stenosis in 34 (85%). 3D-CTA demonstrated the same degree of stenosis in 19 of the 40 lesions (48%), overestimated stenosis in 19, and underestimated stenosis in 2. The MIP of 3D-CTA showed the same degree of stenosis in 21 of the 25 lesions (84%), overstimated stenosis in 3, and understimated stenosis in 1. Different degree of stenosis were found on the snteroposterior and axial projections in 2 of the 40 lesions on MRA, 7 of the 40 lesions on 3D-CTA, and 10 of the 25 lesions on the MIP of 3D-CTA. MIP may solve the difficulty in investigating the degree of stenosis of MCA using the axial projection of DSA. MRA should be performed first to screen for stenotic lesions because of less invasiveness, absence of complications due to contrast medium, no radiation damage, and fewer false negative findings. Uncertain cases should be examined using the MIP of 3D-CTA to achieve the correct diagnosis. This combination of screening tests prevents the performance of unnecessary angiography, and provides a less invasive and correct identification of craniocervical vascular lesions in older patients in whom angiography is difficult to perform.

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The hyponatremia that occurs after subarachnoid hemorrhage (SAH) has recently been thought to be the result of cerebral salt wasting syndrome (CSWS) due to continuous elevation of serum atrial natriuretic peptide (ANP). Although several suthors have reported that serum antidiuretic hormone (ADH) level return to normal within 3 days after SAH, we have experienced patients with high serum ADH levels during the subacute stage (day 9-13) after SAH. We examined the relationship among serum ADH level, ANP level and hyponatremia in 21 patients admitted by day 3 after SAH. High serum ADH level during the subacute stage was noted in 6 cases (6/17, 35%). The incidence of hyponatremia in these patients was 100% (6/6 cases), and much higher than that in patients with normal serum ADH level during the subacute stage (5/11, 46%). This hyponatremia was related to neither the incidence of vasospasm nor patient Glasgow Outcome Scale scores. Thus, contrary to previous reports, we found that 35% of patients with SAH had elevated ADH level during the subacute stage after SAH. If the cause of hyponatremia is unknown, excessive sodium and fluid administration is appropriate for the treatment of hyponatremia after SAH. However, close observation of serum ADH level and water balance is mandatory, since excessive fluid administration may result in the deteriolation of hyponatremia in the presence of ADH elevation.

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To clarify the validity of intraoperative monitoring for preventing complications during carotid endarterctomy (CEA), we investigated the results of 151 CEA operations performed on 140 patients with significant stenosis of the internal carotid artery (ICA). The patients had a mean age of 63 years and a mean ICA stenosis of 64.7%. A T-shaped intraluminal shunt was used as a temporary bypass in each patient. We measured flow and stump pressure in the ICA, and recorded somatosensory evoked potential (SEP) from the ipsilateral parietal area. In 44 patients, oxyhemoglibin (HbO_2) at the ipsilateral frontal area was also monitored by near-infared spectroscopy. Surgery did not result in the death of any patient, but there were 12 (7.9%) instances of transient neurological deterioration and 4 (2.6%) operations resulted in permanent deficits. Patients with an ICA stenosis of ≩ 70% showed a significant decrease in ICA flow ; 3 of them showed a large increase in ICA flow after CEA and developed postoperative neurological deterioration, including 1 permanent deficit, probably due to postoperative hyperperfusion. Eight (25.0%) of 32 patients whose stump pressures were ≨30 mmHg demonstrated postoperative transient neurological deficits. Of 13 patients who showed a disappearance of N20/P25 in SEP, 7 (53.8%) demonstrated postoperative neurologic deterioration, including 1 patient with a permanent deficit. One (10%) of 10 patients who showed a significant decrease in HbO_2 developed a transient neurological deficit. We conclude that intraoperative monitoring was beneficial in terms of reducing operative complications. Monitoring of SEP was most sensitive for detection of cerebral ischemia. However, because SEP cannot provide information on the whole brain, a combination of monitoring methods is needed.

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Aneurysms of the posterior circulation account for 5 to 10% of all intracranial aneurysms. Because of difficulties in surgical intervention for posterior circulation aneurysms, the outcome in affected individuals is poor compared with that for patients with anterior circulation aneurysms. Attempts to provide alternative approaches for therapeutic management of intracranial aneurysms have led to the development of endovascular techniques based on detachable platinum coils. The treatment of 4 patients with posterior circulation aneurysms with the use of interlocking coils and Guglielmi detachable coils is now described. The aneurysms were all small and were located in either the basilar tip (Case 1), the basilar artery-superior cerebellar artery (Case 2), or the vertebral artery-posterior inferior cerebellar artery (Case 3, 4). Immediately after embolization, 90 to 100% obliterlation was achived in all patients. There were no complications during or after the treatment procedure. However, follow-up angiography 1 year after embolization revealed coil compaction in 1 patient. We suggest that the endovascular occlusion technique is a viable alternative for the management of patients with posterior circulation aneurysms associated with high surgical risk. However, additional angiographic follow-up studies are necessary to determine the long-term efficacy of endovascular occlusion techniques.

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Two cases of blepharoptosis subsequent to embolization of a dural arteriovenous fistula in the region of the cavernous sinus are described. The patients were treated by catheterization of the superior ophthalmic vein after incision of the upper eyelid. Patient 1 exhibited severe blepharoptosis that was thought to result from weakness of the levator muscle and subsequent prolonged swelling of the conjunctiva and eyelid, a characteristic symptom of dural arteriovenous fistula. Patient 2 exhibited mild blepharoptosis that was probably caused by partial damage to the levator muscle as a result of suturing of the upper eyelid. We shortened the levator muscle in both patients and achieved good functional and cosmetic results. In neither patient was there a recurrence of the dural arteriovenous fistula.

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The authors report a case of an acoustic neuroma with distinctive angiolographical findings. Tumor stains and feeding arteries are meinly discussed. A 26-year-old male was sdmitted to our hospital because of dizziness, left hemifacial numbness and tinnitus. His left ABR was diminished, though other otological examinations were almost normal. CT scan and MRI demonstrated left cerebellopontine angle tumor with marked dilatation of the internal auditory canal. Left internal carotid angiography disclosed patchy tumor stain supplied from the tentorial artery, a branch of the meningohypophyseal trunk. The preoperative diagnosis was controversial, but the pathological diagnosis was neurinoma. The engiograms of 215 surgically proven acoustic neuromas were reviewed. Thirty-three (15%) of these tumors displayed abnormal tumor stains. This figure is lower than those of former reports, because our study includes small tumors found after the start of the CT/MRI era. The tumor stains were observed in 13% of vertebral angiograms and 4% of external carotid injections, but only one percent of internal carotid injections. On the other hand, twenty-two (73%) out of thirty meningiomas operated on in our institute showed abnormal tumor stains. Thirteen percent of these stains were shown by vertebral sngiography, 43% by external carotid and 57% by internal carotid examinations. Following the introduction of CT/MRI, angiography is not always conclusive in differential diagnosis of cerebellopontine sngle tumors, but it still provides the key information to the surgeons. Differential diagnosis and operative plan should be made based on a combination of all availble data.

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A 44-year-old women who complained of a persistent headache was admitted to Tokai University Hospital. Magnetic resonace imaging (MRI) revealed a dumbbell-shaped tumor penetrating the falx in the frontal area. The tumor was bordered by a linear rim of a low signal intensity. Surgery revealed that the tumor was located in the subarachnoid space and was separated from the brain parenchyma by the pial membrane. In a limited area, the tumor grew along the Virchow-Robin space and invaded the brain parenchyma. Electron microscopy revealed that the tumor possessed a basal lamina structure characteristic of solitary intracranial, extracerebral glioma. The observation that the tumor penetrated the falx without invasion was suggestive of the presence of a natural defect in the falx. Only 13 cases of solitary intracranial, extracerebral glioma have been described previously.

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A case is reported blowout fracture of the orbital floor, which is successfully reconstructed with expanded polytetrafluoroethylene (ePTFE) aheet via transmaxillary approach. This 14-year-old boy presented with diplopia soon after a trauma to the region around the right eye socket sustained during a football game. Neuroimagings revealed a blowout fracture of the right floor and herniation of the inferior rectus muscle into the maxillary sinus. Forced duction of the muscle and administration of steroid and vitamin B 12 for 2 weeks without marked effect. Surgical intervention via transmaxillary route was undertaken. The herniated muscle was repositioned in the orbital cavity and the defect in the orbital floor was reconstructed and closed in 3 layer, i.e., an intraorbital ePTFE sheet, bone chips and an intramaxillary ePTFE aheet sutured to the mucous membrane of the maxillary sinus. Ocular movement has remarkablly improved after surgery. The procedure is presented and indication and timing of the operation are discussed.

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Cerebellar mutism is one of the complications of posterior fossa surgery for the midline mass lesions. We report a case of 4-year-old boy who was performed the surgical resection of astrocytoma located in the fourth ventricle. Preoperatively, he presented with headache and vomiting, which had worsened during a week prior to the admission. Neurological examination revealed papilledema and nystagmus. Computed tomographic scan revealed a vermian tumor filling the fourth ventricle. On the 2 nd postoperative day, he developed mutism with the poor oral intake and emotional lability. His speech began to recover with dysarthria 6 weeks later. In the previous reports cerebellar nutism developed frequently after the resection of the posterior fossa tumors such as medulloblastoma in the vermis. It is conceivable that preoperative intracranial hypertension is a factor of developing cerebellar mutism. Additionaly, developing cerebellar mutism might be associated with the edema and ischema of cerebellar hemisphere caused by the retraction of the cerebellum at the surgery.

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