Ichiro Kawahara

Recanalization after endovascular occlusion of a dissecting aneurysm of the posterior cerebral artery--A case report and review of the literature.

Endovascular occlusion has been accepted as a safe, minimally invasive, and reliable treatment for ruptured dissecting aneurysms. Occlusion of the entire affected area is ideally the most complete treatment for such lesions. However, it is difficult to occlude the entire dissected lesion when it involves side branches due to the short-term risk of side branch occlusion, emboli dislodgement, and the long-term risk of parent artery recanalization. We herein present an extremely rare case where recanalization occurred after endovascular occlusion of a ruptured dissecting aneurysm of the posterior cerebral artery, and discuss its clinical implications. There are three mechanisms of recanalization: coil compaction due to loose or short segment packing, secondary dissection and occlusion of the false lumen. In endovascular occlusion of dissecting aneurysms that involve side branches, it is important to consider the risk of both recanalization and ischemic complications. We should attempt to insert the microcatheter into the true lumen and maintain dense packing as long as possible, unless the coils occlude the side branches following the procedure. Careful follow-up is necessary in all patients that received endovascular treatment.

Radiation-Induced Meningioma following Prophylactic Radiotherapy for Acute Lymphoblastic Leukemia in Childhood

Background: Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy. Although it was considered to be a poor prognostic disease, modern treatment protocols (aggressive chemotherapy and prophylactic cranial irradiation) have resulted in dramatically improved survival rates. In a group of low-risk ALL patients, the 5-year survival rate is estimated to be 85%. However, ALL patients who undergo this treatment are at risk of developing secondary neoplasms related to treatment, which has become an increasingly recognized problem. Case Description: A 3-year-old boy with ALL was successfully treated with chemotherapy (vincristine, prednisolone, mercaptopurine and methotrexate) and prophylactic cranial irradiation (total 18 Gy). At the age of 23, he was admitted to our hospital for weakness in the right leg. Computed tomography and magnetic resonance imaging revealed a parasagittal tumor of the left frontoparietal lobe with perifocal edema. The tumor was completely removed surgically and pathohistologically diagnosed as atypical meningioma. Conclusion: Long-term survivors who received radiotherapy for ALL in childhood are at risk for late complications, including radiation-induced meningioma. Therefore, careful follow-up neurological examinations, for example magnetic resonance imaging, are indicated in these patients. In addition, late complications should be taken into account during the initial planning of prophylactic radiotheraphy dosage, which has implications for informed consent of the patient.

Radiological findings of orbital infarction syndrome following intracranial aneurysm surgery.

Orbital infarction syndrome is a rare disorder resulting from cclusion of the ophthalmic artery and its branches. Zimmerman t al. first reported six patients with proptosis, opthalmoplegia nd blindness immediately after intracranial aneurysm surgery as rbital infarction syndrome [1]. To present, only ten cases (3 litertures) of orbital infarction syndrome after intracranial aneurysm urgery have been reported [1–3]. However two of three literaures were described by ophthalmologists. Neurosurgeons should ay attention to this rare but devastating complication. In order to ssist the early diagnosis of this complication, we report upon two ases of orbital infarction syndrome after intracranial aneurysm urgery.

Dolichoectasic Anterior Cerebral Artery and Hemodynamics

Dolichoectasia of the intracranial arteries is a rare condition, and the vertebrobasilar system and the internal carotid artery are the most commonly involved structures. We report a rare case of idiopathic dolichoectasia of the anterior cerebral artery in a 22-year-old female. The patient caused an automobile accident and was brought to our hospital in an ambulance. A computed tomography scan and magnetic resonance imaging revealed no fresh lesions, but showed a prominent serpentine structure with calcification and flow void in the region of the interhemispheric fissure, which was suspicious for arteriovenous malformation or arteriovenous fistula. Cerebral angiography demonstrated extensive dilatation of the anterior cerebral artery, but no evidence of arteriovenous malformation or arteriovenous fistula. Single photon emission computed tomography revealed hypoperfusion of the right frontal lobe at rest. Electroencephalography showed no epileptic discharge. The patients course was uneventful, and she was discharged with no neurologic deficit. There are few reports of hemodynamic changes in cases of dolichoectasia. In the diagnosis of cerebral dolichoectasia, cerebral hemodynamics should be examined carefully in addition to evaluating vascular disease by angiography.

De novo ruptured aneurysm at the site of anastomosis after superficial temporal artery-middle cerebral artery anastomosis--case report and literature review.

Extracranial (EC)–intracranial (IC) bypass surgery, most comonly superficial temporal artery (STA)–middle cerebral artery MCA) anastomosis, has been established as a surgical procedure or treating major cerebral artery occlusive disease, and the main bject of this procedure is to reduce future ischemic events [1,2]. ignificant alterations in blood-flow patterns and hypertrophic hanges in the caliber of both the EC artery and adjacent segments f the cortical arteries are common after EC-IC bypass. However, ostoperative aneurysm formation at the anastomotic site or in its lose proximity is a relatively rare complication of this procedure 1–11]. We describe a rare case of intracerebral hemorrhage from a uptured aneurysm at the anastomotic site 2 years after STA–MCA nastomosis.

The detection of carotid plaque rupture caused by intraplaque hemorrhage by serial high-resolution magnetic resonance imaging: a case report.

BACKGROUND Plaque rupture is believed to be a critical event that leads to thromboembolic complications in atherosclerotic carotid artery disease. Intraplaque hemorrhage can also cause fibrous cap disruption and may be related to the progression of atherosclerosis. However, the mechanism that leads to fibrous cap disruption is not well defined, and there have been few reports in the literature that carotid plaque rupture could be clearly visualized by serial high-resolution MRI. CASE DESCRIPTION We describe a case of a 79-year-old man who presented with minor ischemic stroke. On diffusion-weighted image, new multiple embolic spots were detected. Plaque rupture caused by intraplaque hemorrhage could be clearly detected by serial high-resolution MRI of the cervical carotid artery. The patient underwent carotid endarterectomy, and an atheromatous plaque was extracted intact for histologic analysis. In the histologic section corresponding to the MRI slices, plaque rupture caused by intraplaque hemorrhage was demonstrated. CONCLUSIONS This case represents a valuable example of artery-to-artery embolisms from a carotid plaque rupture secondary to intraplaque hemorrhage. High-resolution MRI may have important applications in natural history studies and in clinical trials of carotid plaques.