Hiroshi Manabe

Impact of Cerebral Microcirculatory Changes on Cerebral Blood Flow During Cerebral Vasospasm After Aneurysmal Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE Cerebral microcirculatory changes during cerebral vasospasm after aneurysmal subarachnoid hemorrhage (SAH) are still controversial and uncertain. The aim of this study was to investigate the changes of cerebral microcirculation during cerebral vasospasm and to clarify the roles of microcirculatory disturbances in cerebral ischemia by measuring cerebral circulation time (CCT) and regional cerebral blood flow (rCBF). METHODS In 24 cases with aneurysmal SAH, rCBF studies by single-photon emission CT and digital subtraction angiography (DSA) were performed on the same day between 5 and 7 days after SAH and/or within 4 hours after the onset of delayed ischemic neurological deficits. CCT was obtained by analyzing the time-density curve of the contrast media on DSA images and was divided into proximal CCT, which was the circulation time through the extraparenchymal large arteries, and peripheral CCT, which was the circulation time through the intraparenchymal small vessels. They were analyzed in association with rCBF and angiographic vasospasm. RESULTS Severe angiographic vasospasm statistically decreased rCBF, and correlation between the degree of angiographic vasospasm and rCBF was seen (r=0.429, P=0.0006). Peripheral CCT showed strong inverse correlation with rCBF (r=-0.767, P<0.0001). Even in none/mild or moderate angiographic vasospasm, prolonged peripheral CCT was clearly associated with decreased rCBF. CONCLUSIONS In addition to the marked luminal narrowing of large arteries detected as severe angiographic vasospasm, microcirculatory changes detected as prolonged peripheral CCT affected cerebral ischemia during cerebral vasospasm. These results suggested that impaired autoregulatory vasodilation or decreased luminal caliber in intraparenchymal vessels may take part in cerebral ischemia during cerebral vasospasm.

Coil embolisation for ruptured vertebral artery dissection distal to the origin of the posterior inferior cerebellar artery.

Abstract Although many surgical or endovascular treatments for ruptured vertebral artery dissection have been reported, the best treatment is controversial. We treated five cases of ruptured vertebral artery dissection distal to the origin of the posterior inferior cerebellar artery (PICA), using retrievable platinum coils packed in the dissection site and the immediately proximal vertebral artery. All patients had a contralateral vertebral artery of the same calibre or larger. All dissections were occluded completely, together with the portion of the vertebral artery distal to the PICA origin. No complications related to the procedure were seen. The purpose of the treatment is to isolate the dissection from the cerebral circulation. Occlusion of the rupture site, preserving perforating arteries arising from the vertebral artery, would be ideal. Short-segment occlusion by retrievable platinum coils is close to the ideal.

Impairment of anti-platelet-aggregating activity of endothelial cells after experimental subarachnoid hemorrhage.

Background and Purpose Serial changes of anti-platelet-aggregating activity in the endothelial cells after experimental subarachnoid hemorrhage were studied in 30 feline two-hemorrhage models. Methods One hour or 2, 4, 7, or 14 days after mimic subarachnoid hemorrhage, ADP (40 mg/kg) was infused into the basilar artery via the right vertebral artery to activate circulating platelets. Immediately after ADP infusion, the basilar artery was fixed by intra-arterial perfusion with 1.5% glutaraldehyde in 0.1 mol/L phosphate buffer and was removed. The luminal surface was examined under a scanning electron microscope. Results One hour after subarachnoid hemorrhage, no platelets adhered or aggregated on the luminal surface. However, 4 to 7 days after subarachnoid hemorrhage, many platelets were observed adhering or aggregating on the luminal surface. Conclusions These findings suggest the impairment of anti-platelet-aggregating activity of endothelial cells after subarachnoid hemorrhage. This impairment may be involved in inducing cerebral ischemia during cerebral vasospasm by causing platelet adhesion and aggregation.

The posterior inferior cerebellar artery originating from the internal carotid artery, associated with multiple aneurysms

SummaryWe report the rare case of ipsilateral posterior inferior cerebellar artery originating from the carotid artery, and associated with multiple concurrent aneurysms. This is the 23rd reported case of carotid-cerebellar anastomosis and the first case with three concurrent aneurysms reported in the literature. Of the 23 cases, 6 had single aneurysms, 2 had double aneurysms and the present case had triple aneurysms.

Coil embolization of ruptured vertebral dissection in acute stage with interlocking detachable coils

BACKGROUND Although dissecting aneurysm of vertebral artery is known as one of the causes of subarachnoid hemorrhage (SAH) in the posterior circulation, the best surgical treatment method remains controversial. METHOD AND RESULT This 64-year-old woman was admitted to our service with headache due to SAH caused by a ruptured vertebral dissecting aneurysm in the distal portion of the posterior inferior cerebellar artery. After confirming tolerance of parent artery occlusion by temporary balloon occlusion, both the dissection site and the proximal portion of the parent artery were occluded completely by interlocking detachable coils (IDCs) without any ischemic complications. The patient was discharged without any neurologic deficit on the 25th day after the therapy. CONCLUSION The goal of treatment for the ruptured dissecting aneurysm is isolation of the dissection site from the circulation to prevent rerupture. In our case, endovascular occlusion with IDCs was sufficient to reach the goal. In cases with difficulties in the surgical approach, embolization of the dissection site with IDCs should be considered.

Morphological Change of Unruptured Vertebral Artery Dissection on Serial MR Examinations. Evaluation of the Arterial Outer Contour by Basi-parallel Anatomical Scanning (BPAS)-MRI.

Basi-parallel anatomical scanning (BPAS)-MRI is a simple MRI technique to reveal the surface contour of the intracranial vertebrobasilar artery. The purpose of this study was to investigate the usefulness of BPAS-MRI for observing the temporal course of unruptured vertebral artery (VA) dissection in patients by means of serial MR examinations. Since April 2003, we performed serial MR examinations in four patients with unruptured acute vertebral artery dissection. The frequency of the MR examinations during the follow-up period in each patient varied from twice within seven months to five times within 19 months. Both MRA and BPAS-MRI were obtained in each MR examination. We investigated the course of morphological changes within the dissected artery on BPAS-MRI (outer contour) and on MRA (inner lumen). Although the initial MRA showed fusiform dilatation, irregular stenosis or normal caliber at the dissected lesion, the initial BPAS-MRI disclosed fusiform dilatation in all of the four patients. In two patients, MRA finding of the VA lesion had changed, though the fusiform appearance had been stationary on BPAS-MRI. Then both dissolution of the fusiform dilatation on BPAS-MRI and normalization of the inner luminal caliber on MRA were confirmed within nine months. In one patient, fusiform dilatation on both BPAS-MRI and MRA resolved simultaneously on the MR examination at eight months after the initial symptom. In another patient, fusiform dilatation of the outer contour was still enlarging on BPAS-MRI ten months after the onset, though the fusiform dilatation on MRA had been stationary since the eighth week. We performed endovascular coil embolization in this patient eleven months after the initial symptom. Resolution of the fusiform dilatation on BPAS-MRI should be a healing sign of VA dissection. Persisting the fusiform dilatation or progressively enlarging outer contour on BPAS-MRI may be an unstable sign. BPAS-MRI provides more information about the instability of the dissected lesion. We should obtain not only MRA but also BPAS-MRI for the course observation of unruptured VA dissection.

Embolisation of Ruptured Cerebral Aneurysms with Interlocking Detachable Coils in Acute Stage. Acute IDC Embolisation for Ruptured Aneurysms.

Twelve cases of ruptured cerebral aneurysm were treated in acute stage with interlocking detachable coils (IDC, Target Therapeutics, Fremont, California) and the outcome was assessed. IDCs were placed intra-aneurysm for intra-aneurysmal occlusion, or intra-artery for proximal occlusion. Cases: age 36–84 (mean; 60) y.o., 11 females and 1male; 1, 5, 4 and 2 patients were categorised (Hunt and Hess) as grades 1, 2, 3 and 4 respectively. An intra-aneurysmal occlusion in ten cases and a proximal occlusion in two were performed on day 1–11 (mean 4). On angiograms and CT findings, the ruptured point seemed to have occluded in all cases. The occlusion rate was 100% in five cases, 95% in two, 90% in three, 80% in one, and less than 50% in one. There were two cases of technical complication, one a coil migration and the other an aneurysmal perforation with IDC. Their Glasgow Outcome Scale six months after embolisation was graded as good recovery in four cases, moderately disabled state in two, severely disabled state in one, and dead in five. Follow-up angiograms taken four to six months after embolisation showed an intra-aneurysmal coil compaction in five cases. Two of these were treated by a second embolisation or by neck clipping followed by aneurysmal resection, but another two were observed without any treatment and the last one died of rebleeding. Histological examination of the resected embolised aneurysm revealed slight organization around coils but no endothelialisation over the aneurysmal orifice. In our experience, coil embolisation with IDC for acute ruptured aneurysm is a promising means of preventing rerupture during subacute stage.

Incidence of Intracranial Arterial Dissection in Non-emergency Outpatients Complaining of Headache: Preliminary Investigation with MRI/MRA Examinations

PURPOSE Headache is recognized as one of the specific signs of intracranial arterial dissection (ICrAD). We clarified the incidence of ICrAD in non-emergency outpatients complaining of headache and the nature of headache observed in case of ICrAD. PATIENT POPULATION AND METHODS Consecutive non-emergency outpatients coming to the neurological and neurosurgical departments and who underwent MRI and MRA examinations were included in this study. The diagnosis of ICrAD was made when patients met the following two conditions: (1) pearl-and-string sign, pearl sign, or string sign on MRA, and (2) high arterial wall signal on T1 images or intimal flap on T2 images. If possible, cerebral angiography and/or black blood MRI and/or surface-image MRI was also performed in cases meeting these criteria. RESULTS (1) Headache group (172 patients): severe headache was seen in five patients and headache of sudden onset in three. Arterial dissection was diagnosed in eight patients (4.7%, including seven cases of asymptomatic vertebral dissection and one of basilar dissection). The headache noted in most cases of ICrAD was similar to that experienced in daily life. (2) Non-headache group (201 patients): complaints included vertigo/dizziness in 52 patients, gait disturbance in 28, weakness of the arm or leg in 20, and limb numbness in 18, syncope attack in 14, and others in 69. Arterial dissection was diagnosed in six patients (3.0%, including one case of asymptomatic basilar and two of vertebral artery dissection, symptomatic two vertebral and one basilar dissection). CONCLUSION We obtained no evidence of significant difference in the incidence of ICrAD in non-emergency outpatients with (4.7%) and without headache (3.0%). The nature of the headache in the cases of ICrAD was similar to that experienced in daily life. ICrAD with nonspecific headache is more common than previously thought.

Basi-Parallel Anatomical Scanning (BPAS) - MRI: a Simple and Useful MRI Technique for Pre-Procedural Evaluation in Cases of Basilar Artery Occlusion.

Basi-parallel anatomical scanning (BPAS)-MRI is a simple MRI technique that we designed to reveal the surface appearance of the vertebrobasilar artery within the cistern. Because it requires only 2 cm-thick heavily T2-weighted coronal imaging with gray-scale reversal, we can obtain BPAS-MRI with any MR machine of any company. BPAS-MRI can easily show the outer contour of the vertebrobasilar artery even if occluded. Therefore, BPAS-MRI can also reveal the occluded basilar trunk and the shape of basilar top branching that we cannot see with any other imaging modality before the recanalizing interventional procedure. To avoid a dangerous blind manipulation of guidewires or micro-catheters, BPAS-MRI should be obtained prior to the interventional procedure in cases of acute basilar artery occlusion.

Retinal Embolization and Cerebellar Asymptomatic Embolization after Carotid Stenting Using Distal Balloon Protection: A Case Report

We describe a rare case of having both symptomatic ipsilateral retinal embolization and asymptomatic cerebellar embolization occurring after carotid stenting with use of distal protect device. In this case, external carotid angiograms revealed accessory meningeal artery-ophthalmic artery and occipital artery-vertebral artery anastomoses. This case suggested that the protection for external carotid artery should be considered during carotid stenting to avoid retinal embolization and cerebellar or cerebral embolization in cases showing angiographical anastomoses between external carotid artery and ophthalmic artery or intracranial arteries.