Spontaneous Partial Regression of Cerebral Arteriovenous Malformation

Arteriovenous malformation (AVM) of the brain is one of the important pathologic conditions which cause intracerebral or subarachnoid hemorrhage, epilepsy, or chronic cerebral ischemia. The spontaneous regression of cerebral AVM is reported to be very rare and more likely to occur when the AVM is small, is accompanied by hemorrhage, and has fewer arterial feeders. We report a case of right occipital AVM which at follow-up angiography performed four years later showed near-complete spontaneous regression.

CT and MR Imaging Features in Patients with Intracranial Dolichoectasia

PURPOSE: To describe the CT and MR imaging features in patients with intracranial dolichoectasia. MATERIALS AND METHODS: The CT(n=21), MR(n=20) and MRA(n=11) imaging features seen in 28 patients (M:F=12:16 aged beetween 65 and 82 (mean, 65) years with intracranial dolichoectasia were retrospectively reviewed with regard to involved sites, arterial changes(maximum diameter, wall calcification, high signal intensity in the involved artery, as seen on T1-weighted MR images), infarction, hemorrhagic lesion, compression of brain parenchyma or cranial nerves, hydrocephalus and brain atrophy. Involved sites were classified as either type 1 (involvement of only the posterior circulation), type 2 (only the anterior circulation), or type 3 (both). RESULTS: In order of frequency, involved sites were type 1(43%), type 3(36%) and type 2(22%). Dolichoectasia was more frequently seen in the posterior circulation(79%) than in the anterior (57%). Arterial changes as seen on T1-weighted MR images, included dolichoectasia(mean maximum diameter 7.4mm in the distal internal carotid artery, and 6.7mm in the basilar artery), wall calcification(100% in involved arteries) and high signal intensity in involved. Cerebral infarction in the territory of the involved artery was found in all patients, and a moderate degree of infarct was 87%. Hemorrhagic lesions were found in 19 patients(68%); these were either l o b a r ( 53%), petechial(37%), or subarachnoid (16%), and three patients showed intracranial aneurysms, including one case of dissecting aneurysm. In 19 patients(68 %), lesions were compressed lesions by the dolichoectatic arteries, and were found -in order of descending frequency- in the medulla, pons, thalamus, and cerebellopontine angle cistern. Obstructive hydrocephalus was found in two patients (7 %), and 23 (82 % ) showed a moderate degree of brain atrophy. CONCLUSION: In patients with intracranial dolichoectasia, moderate degrees of cerebral infarction and brain atrophy in the territory of involved arteries, as well as hemorrhagic lesions and compression of the brain stem or cranial nerves, were not infrequently seen on CT and MR images. These changes were in addition to the basic arterial change(dolichoectasia, arterial wall calcification and intraluminal high signal intensity) seen on T1-weighted MR images.

Persistent Carotid-Vertebrobasilar Anastomosis: Radiologic Findings

PURPOSE: To evaluate the radiologic findings of carotid-vertebrobasilar anastomosis and associated anomalies. MATERIALS AND METHODS: Thirteen patients with fourteen cases of carotid-vertebrobasilar anastomosis collectedfrom January 1992 to December 1997 were reviewed. Clinical diagnosis refered for cerebral angiography werecerebral infarction(n=3), intracranial hemorrhage(n=2), subarachnoid hemorrhage(n=1), brain tumor(n=3),arteriovenous malformation(n=3) and trigeminal neuralgia(n=1). Cerebral angiograms and clinical symptoms wereretrospectively analyzed. RESULTS: The fourteen carotid-vertebrobasilar anastomsis consisted of eleven cases ofpersistent trigeminal artery and three cases of type I proatantal intersegmental artery. Persistent trigeminalarteries were associated with anterior communicating artery aneurysm(n=1), posterior fossa arteriovenousmalformation(n=2) and persistent trigeminal artery variant(n=5). Type I proatantal intersegmental arteries wereassociated with hypoplastic vertebral arteries(n=2) : only proximal segment in one, and proximal and distalsegments in one case. Only one patient had clinical symptom related to the carotid-vertebrobasilar anastomosiswhich was trigeminal neuralgia. CONCLUSION: Knowledge of the anatomical and radiologic findings ofcarotid-vertebrobasilar anastomosis and associated anomalies will aid in the accurate diagnosis of neurovasculardisease and prevent possible complications during surgical and interventional procedures.