Intracranial Vertebrobasilar Artery Research Articles

Ibudilast, a mixed PDE3/4 inhibitor, causes a selective and nitric oxide/cGMP-independent relaxation of the intracranial vertebrobasilar artery

Ibudilast, a mixed phosphodiesterase (PDE) 3/4 inhibitor, is a cerebral vasodilator widely used in Japan for treating post-stroke dizziness. However, little studies have been conducted on the vasorelaxant effects of PDE inhibitors in the vertebrobasilar artery associated with dizziness onset. The in vitro vasorelaxant properties of ibudilast were, therefore, investigated by comparing with known selective PDE inhibitors, using vertebrobasilar arteries. Vasorelaxant activities of PDE3, PDE4, PDE5 inhibitors, and ibudilast were assessed in 5-hydroxytryptamine precontracted ring preparations from rabbit intracranial and extracranial vertebrobasilar arteries. Ibudilast more selectively relaxed the intracranial than extracranial artery. Similarly, selective PDE3 and PDE4 inhibitors showed higher selectivity for intracranial arteries. Furthermore, like selective PDE4 inhibitor, the vasorelaxation by ibudilast accompanied by increase in cAMP levels was inhibited by the adenylyl cyclase inhibitor SQ22536 in intracranial arteries. Next, it was examined whether nitric oxide (NO)/cGMP signaling is involved in this vasorelaxation in intracranial arteries. The suppression of NO/cGMP signaling by an NO synthase inhibitor or a guanylyl cyclase inhibitor potentiated the vasorelaxion by a PDE3 inhibitor and reduced that by a PDE4 inhibitor, while either suppression of the signaling had little influence on that by ibudilast. These results suggest that ibudilast has the high vasoselectivity for intracranial artery based on a mixed PDE3 and PDE4-inhibition, and effectively relaxes intracranial arteries independently of NO/cGMP signaling because of its vasorelaxation compensated by either PDE3- or PDE4-inhibition depending on the state of NO/cGMP signaling change.

Wingspan experience at Beijing Tiantan Hospital: new insights into the mechanisms of procedural complication from viewing intraoperative transient ischemic attacks during awake stenting for vertebrobasilar stenosis

Background and aimIntracranial vertebrobasilar artery (VBA) stenosis portends a stroke and death rate of 8.5–22.8% annually despite medical therapy. Stenting has emerged as a treatment option but also carries substantial...

Intracranial Vertebrobasilar Artery Dissection Associated with Postpartum Angiopathy

Background. Cervicocephalic arterial dissection (CCAD) is rare in the postpartum period. To our knowledge this is the first reported case of postpartum angiopathy (PPA) presenting with ischemic stroke due to intracranial arterial dissection. Case. A 41-year-old woman presented with blurred vision, headache, and generalized seizures 5 days after delivering twins. She was treated with magnesium for eclampsia. MRI identified multiple posterior circulation infarcts. Angiography identified a complex dissection extending from both intradural vertebral arteries, through the basilar artery, and into both posterior cerebral arteries. Multiple segments of arterial dilatation and narrowing consistent with PPA were present. Xenon enhanced CT (Xe-CT) showed reduced regional cerebral blood flow that is improved with elevation in blood pressure. Conclusion. Intracranial vertebrobasilar dissection causing stroke is a rare complication of pregnancy. Eclampsia and PPA may play a role in its pathogenesis. Blood pressure management may be tailored using quantitative blood flow studies, such as Xe-CT.

Stent-assisted coil embolization followed by a stent-within-a-stent technique for ruptured dissecting aneurysms of the intracranial vertebrobasilar artery

A ruptured dissecting aneurysm of the vertebrobasilar artery (VBA-DA) is a well-known cause of acute subarachnoid hemorrhage (SAH) with a high rate of early rebleeding. Internal trapping of the parent artery, including the dissected segment, is one of the most reliable techniques to prevent rebleeding. However, for a ruptured VBA-DA not suitable for internal trapping, the optimal treatment method has not been well established. The authors describe their experience in treating ruptured VBA-DAs not amenable to internal trapping of the parent artery with stent-assisted coil embolization (SAC) followed by a stent-within-a-stent (SWS) technique. Eleven patients-6 men and 5 women with a mean age of 48 years and each with a ruptured VBA-DA not amenable to internal trapping of the parent artery-underwent an SAC-SWS between November 2005 and October 2007. The feasibility and clinical and angiographic outcomes of this combined procedure were retrospectively evaluated. The SAC-SWS was successful without any treatment-related complications in all 11 patients. Immediate posttreatment angiograms revealed complete obliteration of the DA sac in 3 patients, near-complete obliteration in 7, and partial obliteration in 1. One patient died as a direct consequence of the initial SAH. All 10 surviving patients had excellent clinical outcomes (Glasgow Outcome Scale Score 5) without posttreatment rebleeding during a follow-up period of 8-24 months (mean follow-up 15 months). Angiographic follow-up at 6-12 months after treatment was possible at least once in all surviving patients. Nine VBA-DAs showed complete obliteration; the other aneurysm, which had appeared partially obliterated immediately after treatment, demonstrated progressive obliteration on 2 consecutive follow-up angiography studies. There was no in-stent stenosis or occlusion of the branch or perforating vessels. The SAC-SWS technique seems to be a feasible and effective reconstructive treatment option for a ruptured VBA-DA. The technique may be considered as an alternative therapeutic option in selected patients with ruptured VBA-DAs unsuitable for internal trapping of the parent artery.

Long-Term Outcome of Tandem Stenting for Stenoses of the Intracranial Vertebrobasilar Artery and Vertebral Ostium

Patients with symptomatic atherosclerotic stenosis of the intracranial vertebrobasilar artery (VBA) have a poor prognosis, and those with coexistent intracranial and extracranial stenoses have worse outcomes despite medical therapy. Our aim was to study the long-term outcome of patients with symptomatic atherosclerotic tandem stenoses at the intracranial VBA and the vertebral artery ostium (VAO) after elective stent placement. Ten consecutive patients (mean age, 65.3 years) with this condition underwent elective stent placement at our institution between September 2001 and December 2007. Technical success was defined as stent placement of both VAO and intracranial VBA stenoses with complete stent coverage of the lesions, residual stenosis of < or = 30%, and good antegrade blood flow. The study end point was a composite of any stroke or death within 30 days and ischemic stroke in the VBA territory after 30 days. Technical success was obtained in 9 of 10 patients without any stroke or death within 30 days. During a median follow-up duration of 32 months, 1 patient had a fatal ischemic stroke in the VBA territory at 4 months, and the other 9 patients were free from stroke recurrence. Thus, the annual stroke rate in VBA territory (including any stroke or death within 30 days) was 3.8%. This pilot study shows that elective stent placement for patients with symptomatic atherosclerotic tandem stenoses at the intracranial VBA and VAO has an acceptable long-term outcome and may be considered as an alternative to medical therapy.

Duplex color-coded ultrasonography for evaluation of the vertebrobasilar arteries

Duplex color-coded ultrasonography performed for evaluation of the cerebrovascular arterial system consists of transcranial and carotid ultrasonogaphy. Vertebral arteries (VAs) pass through the foramina of the cervical transverse processes and unite to form the basilar artery, which affects the blood flow in each vertebral artery. Neck motions also affect the blood flow in the VAs. Carotid ultrasonography enables us to diagnose occlusion of the VAs, the subclavian steal phenomenon, VA dissection, and the Bow-Hunter syndrome. These disturbances of blood supply in the VAs often cause vertigo and dizziness, which result in vertebrobasilar insufficiency, sometimes resulting in cerebral infarction. The level of VA occlusion is diagnosed as follows; 1) Absence of apparent flow signals in the VAs indicates origin occlusion. 2) Preserved systolic velocity, but zero end-diastolic velocity indicates occlusion before the branching off into the posterior inferior cerebellar arteries (PICA). 3) Mean velocity (MV)<18cm/sec and MV-ratio (mean flow velocity in the contralateral VA divided by that in the target VA)≥1.4 indicate PICA-end or VA occlusion after branching off of the PICA. These could be further distinguished as follows: A diameter-ratio (diameter of the contralateral VA divided by the diameter of the target VA)≥1.4 indicates PICA-end occlusion. A diameter-ratio<1.4 indicates VA occlusion after branching off of the PICA. Retrograde VA flow indicates the subclavian steal phenomenon, which can cause vertebrobasilar ischemia during exercise of the upper extremeties. Neck motions sometimes damage the VAs and cause dissection, which produces flaps and stenoses in the VAs. Rotational VA occlusion, the so-called Bow-Hunter syndrome, can be diagnosed by transient change of the blood flow velocity to the occlusive pattern during neck rotations. Transcranial ultrasonography allows direct evaluation of the blood flow in the intracranial vertebrobasilar arteries. This method enables us to confirm the results of carotid ultrasonography, such as in basilar artery occlusion, in which retrograde flow is observed in the basilar artery. Duplex color-coded ultrasonography is less invasive and feasible for bedside examination, and allows real-time evaluation of the cerebrovascular arteries.

Stenting of Symptomatic Basilar and Vertebral Artery Stenosis in Patients Resistant to Optimal Medical Prevention: The Lyon Stroke Unit Experience

Intracranial angioplasty stenting may be an efficient therapy in patients with intracranial atherosclerotic symptomatic vertebrobasilar artery stenosis unresponsive to optimal medical therapy. We present our experience in this setting. Results: The study included 12 cases (8 men, 4 women), with an age range of 43–78 years (mean 62.6 years). Intracranial stenosis that resulted in qualifying stroke or transient ischemic attack involved the vertebral artery (n = 4), lower basilar artery (n = 1) and mid basilar artery (n = 5). Tandem stenosis included the intracranial vertebral artery and basilar artery (n = 1) and both intracranial vertebral arteries (n = 1). The degree of stenosis ranged between 70 and 90% in the basilar and vertebral arteries. Angioplasty + stenting was performed in all lesions. A successful procedure resulting in 30% of residual stenosis was found in 14 vessels. A periprocedural adverse event occurred in 1 case and was related to a brain hemorrhage. The mean patient follow-up was 15 ± 3 months; 10 patients remained symptom free. All patients underwent a percutaneous endovascular balloon angioplasty and stent placement. Conclusions:This study supports the safety and the potential efficiency of stent-assisted angioplasty in patients resistant to optimal prevention. Randomized larger prospective trials are needed to confirm the benefit of this approach.

Long-term outcome of elective stenting for symptomatic intracranial vertebrobasilar stenosis

Seventy-nine consecutive patients with symptomatic atherosclerotic stenosis > or = 50% of intracranial vertebrobasilar artery (VBA) were treated by elective stenting. There were five strokes within 30 days, and three strokes in the VBA territory after 30 days (mean of 812 days). The annual stroke rate in the VBA territory (including any stroke and death within 30 days) was 4.6%. At the last follow-up time, 73 patients were independent (modified Rankin scale grade < or = 2). The outcome compares favorably with medical therapy.

Langzeitergebnisse nach Behandlung intrakranieller vertebrobasilärer Stenosen mit Stents

Recurrent ischemic symptoms attributable to intracranial high-grade vertebrobasilar artery stenoses are associated with a high risk of ischemic stroke, particularly if these occur in spite of aggressive medical treatment. Long term efficacy data for endovascular stent angioplasty of symptomatic intracranial stenoses are lacking. The purpose of this prospective study is to determine the rates of deaths, of ischemic events and of restenosis during long-term follow-up. Between June 2001 and February 2004 twelve patients (11 male, 1 female; median 63 yrs; range, 46 - 75 yrs) with recurrent ischemic symptoms attributed to > or = 70 % intracranial vertebro-basilar artery stenoses, who had failed aggressive medical treatment, were included. Median follow-up was 24 months (range: 6 to 36 months). Intracranial stenoses were measured using 3D rotation angiography data sets and treated with balloon expandable stents. All patients were scheduled for follow-up including clinical (Barthel Index) and transcranial Doppler examinations and intraarterial angiography at 6 months after intervention. Clinical outcome was defined as the rate of stroke in any vascular territory or death during follow-up. Vascular outcome was determined by the rate of in-stent restenosis 50 % on follow-up as examined by intraarterial angiography at 6 months or by transcranial color-coded duplex sonography. Stent placement was technically successful in all patients. No patient had further cerebral ischemic symptoms; two patients died (1 myocardial infarct, 1 sudden death) during follow-up of median 24 months. The degree of stenoses was reduced from median 81 % (range 69 - 94 %) to 19 % (range 10 - 36 %) immediately after stent placement and to 32 % (range 22 - 48 %) after 6 months. No restenosis > or = 50 % occurred during follow-up. Based on this limited series, we believe that in patients, with recurrent symptoms despite aggressive medical treatment, endovascular stent placement in intracranial high-grade vertebrobasilar artery stenoses can be an effective and safe treatment option.

Morphological Change of Unruptured Vertebral Artery Dissection on Serial MR Examinations

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 BPASMRI (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 BPASMRI 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.

頭蓋内椎骨脳底動脈系動脈硬化性狭窄病変に対するａｎｇｉｏｐｌａｓｔｙおよびｓｔｅｎｔｉｎｇの臨床成績

Recently, angioplasty/stenting has been reported as a treatment option for intracranial atherosclerotic stenosis. We describe clinical results of angioplasty/stenting for 21 patients with intracranial vertebrobasilar stenosis (21 lesions). The procedure was performed under local anesthesia via the percutaneous transfemoral route. In 13 cases, we performed angioplasty only, while we used stents in 8 of 21 cases. The mean stenosis in 13 cases of angioplasty decreased from 76.2% to 26.4%, while 82.5% of the stenotic rate remarkably reduced to 11.3% in 8 cases of stenting. The 30-day morbidity and 30-day mortality rate were 4.8% and 0%, respectively. There was only 1 hemorrhagic complication (cerebellar hemorrhage) in case of stenting, and no ischemic events during or after the procedures. Restenosis (more than 50%) occurred in 3 of 21 cases (14.3%) during the mean follow-up period of 12 months. Our procedure-related morbidity and mortality rates were possibly not higher than those reported by other authors. In this study, angioplasty/stenting for intracranial vertebrobasilar artery stenosis was an effective treatment, but strict indications may be required because the procedure-related 30-day morbidity rate was still high compared with that of extracranial atherosclerotic stenosis, in addition to unknown natural history of intracranial vertebrobasilar stenosis.

症候性頭蓋内椎骨脳底動脈狭窄に対する血管内治療

Patients who have symptomatic, medically refractory, vertebrobasilar artery stenosis have a high risk of stroke. The benefits of vascular reconstruction surgery and balloon angioplasty for these lesions are limited, and these treatments are associated with considerable complications. Recently stent placement in the intracranial arteries became available and is expected to improve the results of endovascular treatments. We review our experience with endovascular treatment for symptomatic intracranial vertebrobasilar artery stenosis. Forty patients with intracranial vertebrobasilar artery stenosis were treated with endovascular surgery. Indication of the endovascular surgery was medically refractory symptomatic patients with over 60% angiographical stenosis. Balloon angioplasty was firstly performed in all patients. Stenting was performed only in cases with insufficient dilatation, dissection or restenosis after balloon angioplasty. Successful dilatation was obtained in all cases. Twelve patients underwent stenting in initial treatments. The stenosis rate reduced to 25.2% after balloon angioplasty and 16.1% after stenting. No neurological complications occurred after procedure. The restenosis rates after treatments were 25.9% after balloon angioplasty and 23.5% after stenting. During the follow-up period, only 1 patient developed stroke of posterior circulation. Endovascular surgery for symptomatic vertebrobasilar artery stenosis has become more feasible and safer after the introduction of stenting. Prevention of restenosis is the next problem to be solved.

Clinical Results of Percutaneous Transluminal Angioplasty and Stenting for Intracranial Vertebrobasilar Atherosclerotic Stenoses and Occlusions

Eighteen patients with intracranial vertebrobasilar stenosis and occlusion were treated by PTA or stenting. In 11 of 18 cases, only PTA was performed and in seven of 18 cases, we used stents. The mean stenosis before and after PTA/stenting was 82.8% and 22.3%, respectively. In 11 cases of PTA only, the stenotic rate decreased from 81.8% to 29.6%, while 85.0% of the stenotic rate remarkably reduced to 6.0% in seven cases of stenting. The 30 days morbidity and 30 days mortality rate were 5.5% and 5.5%, respectively. There was only one haemorrhagic complication (cerebellar haemorrhage) in cases of stenting, and no ischemic events during or after the procedures. Restenosis (more than 50% stenosis) occurred in four of 18 cases(22.2%) during mean followup period of 12 months. Two patients with VA occlusion before treatment, developed restenosis and reocclusion. Complete total occlusion seems to be a high-risk lesion and strict follow-up is required. In this study, PTA/stenting for intracranial vertebrobasilar artery stenosis or occlusion is an effective treatment, but strict indications may be required because procedure-related 30 days morbidity rate was 5.5% in addition to unclear natural history.

Staged stent-assisted angioplasty for symptomatic intracranial vertebrobasilar artery stenosis.

Medically refractory symptomatic vertebrobasilar atherosclerotic disease has a poor prognosis. Studies have shown that longer (> or = 10 mm), eccentric, high-grade (> 70%) stenoses portend increased procedure-related morbidity. The authors reviewed their experience to determine whether a staged procedure consisting of angioplasty followed by delayed (> or = 1 month later) repeated angioplasty and stent placement reduces the morbidity associated with endovascular treatment of symptomatic basilar and/or intracranial vertebral artery (VA) stenoses. The authors retrospectively reviewed the medical records in a consecutive series of eight patients who underwent planned stent-assisted angioplasty for medically refractory, symptomatic atherosclerotic disease of the intracranial posterior circulation between February 1999 and January 2002. Staged stent-assisted angioplasty was planned for these patients because the extent and degree of stenosis of the VA and/or basilar artery (BA) lesion portended an excessive procedure-related risk. The degree of stenosis, recent onset of symptoms (unstable plaque), vessel tortuosity, and lesion length and morphological feaures were contributing factors in determining procedure-related risk. Patient records were analyzed for location and degree of stenosis, preprocedural regimen of antiplatelet and/or anticoagulation agents, devices used, procedure-related complications, and clinical and radiographic outcomes. Among the patients in whom staged stent-assisted angioplasty was planned, vessel dissection, which necessitated immediate stent placement, occurred during passage of the balloon in one of them. In a second patient, the stent could not be maneuvered through the tortuous VA. In a third patient, the VA and BAs remained widely patent after angioplasty alone, and therefore stent placement was not required. Significant complications among the eight patients included transient aphasia and hemiparesis in one and a groin hematoma that necessitated surgical intervention in another; there was no permanent neurological morbidity. The mean stenosis before treatment was 78%, which fell to 54% after angioplasty, and the mean residual stenosis after stent placement was 30%. At the last follow-up examination, none of the treated patients had further symptoms attributable to the treated stenosis. The novel combination of initial angioplasty followed by delayed endoluminal stent placement may reduce the neurological morbidity associated with endovascular treatment of long, high-grade stenotic lesions. Attempting to cross high-grade stenoses with higher-profile devices such as stents may result in an embolic shower. Furthermore, neointimal proliferation and scar formation after angioplasty result in a thickened fibrous layer, which may be protective during delayed stent deployment. Larger-scale studies involving multiple centers are needed to elucidate further the lesion morphological characteristics and patient population most likely to benefit from staged procedures.

ステント留置が有効であった頭蓋内椎骨脳底動脈解離性閉塞性病変の２例

We report 2 cases of stenting for occlusive lesions due to wall dissection of the intracranial vertebrobasilar arteries. The first case concerns a 58 year-old man who had dizziness due to restenosis, 6 months after balloon angioplasty. He underwent balloon angioplasty for restenosis. The angioplasty was complicated by acute occlusion due to wall dissection. The acute occlusion of the lesion was completely recanalized by implanting a balloon-expandable stent. The second case concerns a 50 year-old man who had progressive ischemic symptoms due to spontaneous dissection of basilar artery. The symptoms progressed in spite of anticoagulation therapy. The lesion was successfully treated with stenting.

Clinical and neuroradiological features of intracranial vertebrobasilar artery dissection.

We sought to determine the clinical and neuroradiological features of intracranial vertebrobasilar artery dissection. The clinical features and MR findings of 31 patients (20 men and 11 women) with intracranial vertebrobasilar artery dissections confirmed by vertebral angiography were analyzed retrospectively. The vertebral angiography revealed the double lumen sign in 11 patients (13 arteries) and the pearl and string sign in 20 patients (28 arteries). The patients ranged in age from 25 to 82 years (mean, 54.8 years). Clinical symptoms due to ischemic cerebellar and/or brain stem lesions were common, but in 3 cases the dissections were discovered incidentally while an unrelated disorder was investigated. Headache, which has been emphasized as the only specific clinical sign of vertebrobasilar artery dissection, was found in 55% of the patients. Intramural hematoma on T1-weighted images has been emphasized as a specific MR finding. The positive rate of intramural hematoma was 32%. Double lumen on 3-dimensional (3-D) spoiled gradient-recalled acquisition (SPGR) images after the injection of contrast medium was identified in 87% of the patients. The 3-D SPGR imaging method is considered useful for the screening of vertebrobasilar artery dissection. Intracranial vertebrobasilar artery dissection is probably much more frequent than previously considered. Such patients may present no or only minor symptoms. Neuroradiological screening for posterior circulation requires MR examinations, including contrast-enhanced 3-D SPGR. Angiography may be necessary for the definite diagnosis of intracranial vertebrobasilar artery dissection because the sensitivity of the finding of intramural hematoma is not satisfactory.

出血型椎骨脳底動脈系解離性動脈瘤

Fifteen patients of ruptured intracranial vertebrobasilar artery dissection (VBDA) were studied to clarify the clinical problems during treatment. Subsequent rebleeding occurred in 5 of the 15 cases (33.3%) and the mortality rate of patients with rebleeding was 40%. All subsequent rebleeding cases were VBDA of the distal to PICA type. These patients were divided into two groups consisting of a surgical treatment group (chronic stage) with 9 cases and a nonsurgical treatment group with 6 cases. Surgical procedures included proximal occlusion (PO) of the vertebral artery in 7 patients, wrapping in 1 and direct clipping in 1. Postoperative complications occurred in 3 patients by PO. Although proximal occlusion seemed to be a simple and useful method to prevent rebleeding, the occurrence of ischemic complication remains to be solved. Further study is needed to determine the best treatments, including PO for VBDA.

Magnetic resonance imaging study of intracranial vertebrobasilar artery dissections.

The purpose of this study is to demonstrate the magnetic resonance features of intracranial vertebrobasilar artery dissections and to determine the potential and limitations of magnetic resonance imaging in their diagnosis. We studied five consecutive patients with angiographically verified intracranial vertebrobasilar artery dissection with magnetic resonance imaging (0.5 T) in regard to the shapes of the intramural hematoma and the chronological change of its signal intensity. We also estimated the sensitivity of magnetic resonance imaging for diagnosing dissection. We observed intramural hematoma in four patients on the first magnetic resonance scan and in all five patients during the course of the study. The shapes of the intramural hematomas were curvilinear, crescentic, "bamboo-cut," "band-like," and spotty. The intensity of the intramural hematoma varied according to its age. On the T1-weighted and the proton images, the intramural hematomas appeared isointense to slightly hyperintense in the first few days and became hyperintense thereafter. The intramural hematomas became isointense or unrecognizable 2 months after onset. The T1-weighted image and the proton images were superior to the T2-weighted image in demonstrating the intramural hematomas. Magnetic resonance imaging is a sensitive tool for diagnosing intracranial vertebrobasilar artery dissection, particularly in the subacute to early chronic stage. Magnetic resonance imaging is complementary to angiography in that it can directly visualize intramural hematomas.

クモ膜下出血で発症した椎骨脳底動脈解離性動脈瘤の病理所見とその特異性

クモ膜下出血で発症した椎骨脳底動脈解離性動脈瘤の病理所見とその特異性

Re. Calibration of peak expiratory flow (PEF) measuring devices

Seventy-nine consecutive patients with symptomatic atherosclerotic stenosis ≥ 50% of intracranial vertebrobasilar artery (VBA) were treated by elective stenting. There were five strokes within 30 days, and three strokes in the VBA territory after 30 days (mean of 812 days). The annual stroke rate in the VBA territory (including any stroke and death within 30 days) was 4.6%. At the last follow-up time, 73 patients were independent (modified Rankin scale grade ≤ 2). The outcome compares favorably with medical therapy.