The intracranial vertebral artery: a neglected species. The Johann jacob wepfer award 2012

Among posterior circulation arteries, the intracranial vertebral artery (ICVA) has been given the least attention, especially concerning treatment of occlusive lesions. Early clinicopathological studies showed that the ICVA was often occluded in patients with lateral medullary and posterior inferior cerebellar infarcts. Severe stenosis or occlusion of the ICVA was the most common arterial lesion among the 408 patients in the New England Medical Center Posterior Circulation Registry (NEMC-PCR). In this registry, the distal portion of the artery was most often involved, sometimes with spread into the basilar artery. ICVA occlusive lesions were often bilateral and very often accompanied by basilar and cervical vertebral artery occlusive lesions. Patients with bilateral ICVA occlusions often had attacks of dizziness, blurred vision, and ataxia during months and years but rarely later developed disabling infarction. Most posterior circulation infarcts in patients with ICVA occlusive lesions were located in the middle and distal posterior circulation territories and were rostral to the medulla and inferior cerebellum. Although diagnostic techniques now image the ICVA and its lesions well, the optimal treatment of patients with various ICVA occlusive lesions has very rarely been analyzed or reported. The therapeutics of patients with ICVA disease is uncharted territory and begs for attention and clarification.     

Bilateral intracranial vertebral artery disease in the New England Medical Center, Posterior Circulation Registry.

BACKGROUND: Previous studies of patients with bilateral intracranial vertebral artery (ICVA) disease were selective and retrospective. METHODS: We studied risk factors, vascular lesions, symptoms, signs, and outcomes in patients with bilateral ICVA disease among 430 patients in the New England Medical Center Posterior Circulation Registry. RESULTS: Forty-two patients had bilateral ICVA occlusive disease (18 had bilateral stenosis; 16, unilateral occlusion and contralateral stenosis; and 8, bilateral occlusion). The most common risk factors were hypertension (32/42 [76%]) and hyperlipidemia (22/42 [52%]). Sixteen patients (38%) had transient ischemic attacks (TIAs) only; 18 (43%), TIAs before stroke. Occlusive vascular disease also involved the basilar artery in 29 patients (69%), the extracranial vertebral arteries in 18 (43%), and the internal carotid arteries in 11 (26%). Only 6 patients had no other major vascular lesion. Cerebellar symptoms were common. Among 30 patients with infarction, 21 (70%) had proximal intracranial territory involvement, and 15 (50%) had distal territory involvement. The location of occlusive lesions in relation to posterior inferior cerebellar artery origins did not significantly influence prognosis. During follow-up, 31 patients had no symptoms or slight disability, 2 had progression, and 7 died. Among 7 patients with poor outcome, 6 also had basilar artery stenosis or occlusion and 5 had proximal and distal intracranial territory infarcts. CONCLUSIONS: Most patients with bilateral ICVA occlusive disease have hypertension, other major occlusive lesions, and TIAs before stroke. Short- and long-term outcomes are usually favorable, but patients with bilateral ICVA and basilar artery-occlusive lesions often have poor outcomes.     

New England Medical Center Posterior Circulation Stroke Registry: I. Methods, Data Base, Distribution of Brain Lesions, Stroke Mechanisms, and Outcomes

Among 407 New England Medical Center Posterior Circulation Registry (NEMC-PCR) patients, 59% had strokes without transient ischemic attacks (TIAs), 24% had TIAs before strokes, and 16% had only posterior circulation TIAs. Embolism was the commonest stroke mechanism accounting for 40% of cases (24% cardiac origin, 14% arterial origin, 2% had potential cardiac and arterial sources). In 32%, large artery occlusive lesions caused hemodynamic brain infarction. Stroke mechanisms in the posterior and anterior circulation are very similar. Infarcts most often included the distal posterior circulation territory (rostral brainstem, superior cerebellum and occipital and temporal lobes), while the proximal (medulla and posterior inferior cerebellum) and middle (pons and anterior inferior cerebellum) territories were equally involved. Infarcts that included the distal territory were twice as common as those that included the proximal or middle territories. Most distal territory infarcts were attributable to embolism. Thirty day mortality was low (3.6%). Embolic stroke mechanism, distal territory location, and basilar artery occlusive disease conveyed the worst prognosis.     

New England Medical Center Posterior Circulation registry

Among 407 New England Medical Center Posterior Circulation registry patients, 59% had strokes without transient ischemic attacks (TIAs), 24% had TIAs then strokes, and 16% had only TIAs. Embolism was the commonest stroke mechanism (40% of patients including 24% cardiac origin, 14% intraarterial, 2% cardiac and arterial sources). In 32% large artery occlusive lesions caused hemodynamic brain ischemia. Infarcts most often included the distal posterior circulation territory (rostral brainstem, superior cerebellum and occipital and temporal lobes); the proximal (medulla and posterior inferior cerebellum) and middle (pons and anterior inferior cerebellum) territories were equally involved. Severe occlusive lesions (>50% stenosis) involved more than one large artery in 148 patients; 134 had one artery site involved unilaterally or bilaterally. The commonest occlusive sites were: extracranial vertebral artery (52 patients, 15 bilateral) intracranial vertebral artery (40 patients, 12 bilateral), basilar artery (46 patients). Intraarterial embolism was the commonest mechanism of brain infarction in patients with vertebral artery occlusive disease. Thirty-day mortality was 3.6%. Embolic mechanism, distal territory location, and basilar artery occlusive disease carried the poorest prognosis. The best outcome was in patients who had multiple arterial occlusive sites; they had position-sensitive TIAs during months to years.     

Atherothrombotic cerebellar infarction: vascular lesion-MRI correlation of 31 cases.

BACKGROUND AND PURPOSE: Correlation of MRI findings with atherosclerotic vascular lesions has rarely been attempted in patients with cerebellar infarction. The aim of this study was to correlate the MRI lesions with the vascular lesions seen on conventional cerebral angiography in cerebellar infarction. METHODS: The subjects included 31 patients with cerebellar infarcts who underwent both MRI and conventional cerebral angiography. We analyzed the risk factors, clinical findings, imaging study, and angiography results. We attempted to correlate MRI lesions with the vascular lesions shown in the angiograms. RESULTS: The vascular lesions seen on angiograms were subdivided into 3 groups: large-artery disease (n=22), in situ branch artery disease (n=6), and no angiographic disease with hypertension (n=3). The proximal segment (V1) lesions of vertebral artery were the most common angiographic features in patients with large-artery disease in which stroke most commonly involved the posterior inferior cerebellar artery (PICA) cerebellum. The V1 lesions with coexistent occlusive lesions of the intracranial vertebral and basilar arteries were correlated with cerebellar infarcts, which had no predilection for certain cerebellar territory. The intracranial occlusive disease without V1 lesion was usually correlated with small cerebellar lesions in PICA and superior cerebellar artery (SCA) cerebellum. The subclavian artery or brachiocephalic trunk lesion was associated with small cerebellar infarcts. The in situ branch artery disease was correlated with the PICA cerebellum lesions, which were territorial or nonterritorial infarct. No angiographic disease with hypertension was associated with small-sized cerebellar infarcts within the SCA, anterior inferior cerebellar artery, or SCA cerebellum. CONCLUSIONS: Our study indicates that the topographic heterogeneity of cerebellar infarcts are correlated with diverse angiographic findings. The result that large-artery disease, in which nonterritorial infarcts are more common than territorial infarcts, is more prevalent than in situ branch artery disease or small-artery disease, suggest that even a small cerebellar infarct can be a clue to the presence of large-artery disease.     

小脑梗死的分型与后循环血管病变

目的 研究有无大血管病变患者小脑梗死灶的特征,探讨小脑梗死分型与后循环血管病变的关系。 方法 收集我科自2006年1月～2008年3月期间住院的小脑梗死患者共35例,所有患者均同时具备颅脑磁共振成像（magnetic resonance imaging,MRI）和血管造影检查,包括计算机断层摄影血管造影（computed tomographic angiography,CTA）、磁共振血管造影（magnetic resonance angiography,MRA）和数字减影血管造影（digital subtraction angiography,DSA）检查。根据血管造影检查的结果将入组患者分为两组：大血管病变组20例,小血管病变组15例,分析两组小脑梗死的分型和后循环血管病变（包括狭窄或闭塞）的关系。 结果 ⑴大血管病变组20例中,颅内血管（椎动脉颅内段或基底动脉）病变最多见（10例,50%）,梗死类型多为分水岭梗死（7例,70%）;其次为颅外血管合并颅内血管（椎动脉颅外段合并颅内段或基底动脉）病变（8例,40%）,梗死灶多为小脑后下动脉（PICA）供血区的区域性梗死（7例,87.5%）;单独颅外血管（椎动脉颅外段）病变最少见（2例,10%）,梗死分布无明显倾向性。⑵小血管病变组15例中,梗死灶亦多位于分水岭区（9例,60%）。 结论 由于小脑血液供应特点,小脑梗死中分水岭梗死和腔隙性梗死较区域性梗死更为常见。小梗死灶（直径≤2cm）可能存在后循环大血管的狭窄或闭塞,应予积极的治疗和干预,以防病情加重。     

Clinical and angiographic comparison of asymptomatic occlusive cerebrovascular disease

We compared clinical and arteriographic features in 106 patients with symptomatic unilateral carotid territory occlusive disease to determine the frequency and distribution of occlusive arterial lesions in asymptomatic vessels. Among black patients who were predominantly from Chicago, young, and female, there were fewer transient ischemic attacks and myocardial infarcts, less claudication, and more asymptomatic lesions of the supraclinoid internal carotid artery, anterior cerebral artery stem, and the middle cerebral artery stem. Among white patients predominantly from New England, elderly, and male, there was more frequent and severe occlusive asymptomatic disease at extracranial carotid and vertebral artery sites. Knowledge of the distribution of asymptomatic lesions will help guide evaluation and treatment strategies for patients with occlusive cerebrovascular disease.     

MR angiographic evaluation of carotid and intracranial arteries in Japanese patients scheduled for coronary artery bypass grafting

BACKGROUND AND PURPOSE: Stroke is a serious complication of coronary artery bypass grafting (CABG). Preoperative evaluation of the cerebral arteries to identify patients at increased risk of stroke after CABG is important. In a prospective study, we evaluated cerebral artery occlusive lesions with MR angiography in Japanese patients scheduled to undergo CABG to determine the prevalence of occlusive diseases in the extracranial carotid and intracranial arteries in this population and to identify preoperative risk factors for these patients. METHODS: The subjects were 151 consecutive patients (115 men and 36 women ranging in age from 41 to 82 years) who were scheduled for CABG under nonemergency conditions between October 1995 and February 1998. Carotid and intracranial arteries were examined for occlusive lesions with MR angiography. Patient demographics and risk factors including age, sex, hypertension, diabetes mellitus, hyperlipidemia, smoking habit, history of stroke, peripheral vascular disease and preoperative thromboembolic infarcts revealed by MR imaging were recorded and analyzed. RESULTS: Cervical carotid artery stenoses of more than 50% narrowing were detected in 16.6% of the subjects, and intracranial artery stenoses of more than 50% narrowing were detected in 21.2% of the subjects. Multiple logistic regression analyses identified peripheral vascular disease and lacunar infarcts in the basal ganglia as significant and independent predictors of cervical carotid arterial stenoses. No significant predictor for intracranial arterial stenoses was identified. CONCLUSIONS: The prevalence of extracranial carotid and intracranial artery stenosis in Japanese patients scheduled for CABG is considerably high. MR angiography is of value of identifying these patients. Preoperative evaluation of cranial arteries is recommended, particularly in patients with peripheral vascular disease and infarcts in the basal ganglia.     

Racial differences in the distribution of posterior circulation occlusive disease

We compared clinical and arteriographic features in 27 white and 24 black patients with symptomatic posterior circulation occlusive disease. The degree of arterial stenosis was measured independently by two examiners at 12 sites within the vertebrobasilar territory. Racial comparisons were made based upon the distribution of extra- and intracranial occlusive lesions and symptomatic sites of the lesions. White patients had significantly more angina pectoris, more lesions of the origin of the left vertebral artery and more high grade lesions of the extracranial vertebral arteries. Black patients had significantly higher mean diastolic blood pressure, more diabetes mellitus, more lesions of the distal basilar artery, more high grade lesions of intracranial branch vessels and more symptomatic intracranial branch disease. Race was found to be the only factor increasing the risk of intracranial posterior circulation occlusive disease. Knowledge of the contribution of race to the distribution of posterior circulation lesions will help guide evaluation and treatment strategies for patients with vertebrobasilar occlusive disease.     

Limb ataxia and proximal intracranial territory brain infarcts: clinical and topographical correlations

Background

Limb ataxia is classically attributed to cerebellar hemispheric lesions, although isolated lesions of the inferior cerebellar peduncle (ICP) in the medulla may also cause this sign. It is still unclear why only some patients with acute cerebellar infarcts in the posterior inferior cerebellar artery (PICA) territory present with limb ataxia. The proximal intracranial posterior circulation (P‐PC) territory includes structures fed by the intracranial vertebral arteries (ICVAs): the medulla, supplied by small ICVAs branches, and posterior inferior portion of the cerebellum, fed by PICA. ICP and PICA territory cerebellar infarcts most often occur independently but occasionally occur together.

Objective

To identify structures responsible for limb ataxia in acute P‐PC brain infarcts, correlating clinical and topographical findings.

Methods

Sixteen patients (8 women) were included, aged 30–82 years (mean 62 years), with isolated acute strokes in the P‐PC territory.

Results

The cases reported here indicate that limb ataxia in acute P‐PC territory infarcts may be associated with damage to the ICP in the dorsolateral medulla, regardless of a hemispheric cerebellar lesion. In fact, among the nine patients with PICA stroke, limb ataxia was observed only in the two patients who also presented damage to the dorsolateral medulla involving the ICP. Of the seven patients with isolated dorsolateral medullary infarct, only five patients with ICP damage had limb ataxia.

Conclusions

When correlating limb ataxia and acute P‐PC infarcts, it is important to take into account the entire ICVA territory.Limb ataxia is characterised by dysmetria, dyssynergia and intention tremor, and is clinically assessed by the finger‐to‐nose and heel‐to‐knee tests.¹ It is classically associated with hemispheric cerebellar lesions² and rarely with brainstem lesions.³ Previous reports on cerebellar strokes focused on the frequency of neurological signs in patients with different cerebellar arterial territory infarcts.^4,5 Limb ataxia was reported in only approximately 50% of cases of posterior inferior cerebellar artery (PICA) infarcts but it was not related to the histological or neuroradiological findings.^4,5 A very recent clinical and MRI study⁶ reported limb ataxia in only 4 of 13 patients with acute PICA stroke. The authors correlated this finding with impairment of the intermediate and lateral cerebellar cortex or of the cerebellar nuclei, which are involved in the control of limb coordination. However, it is well known that lesions of the inferior cerebellar peduncle (ICP) without involvement of the cerebellar hemisphere may also cause limb ataxia.⁷The proximal intracranial posterior circulation (P‐PC) territory includes structures fed by the intracranial vertebral arteries (ICVAs), the medulla and the posterior inferior portion of the cerebellum. The blood supply of the posterior inferior cerebellum and the ICP derive from different branches of the ICVAs. The lateral medulla is supplied by small branches that originate from the ICVA and course through the lateral medullary fossa to supply the ICP and the dorsolateral medulla. The ICVA also gives rise to the PICA. The medial branch of the PICA supplies a small portion of the dorsal medulla but not the ICP. ICP and PICA territory cerebellar infarcts most often occur independently but occasionally occur together. Only 1 in 5 proximal territory infarcts include both the lateral medulla and the PICA territory cerebellum.⁸ When both occur together it is usually caused by a long occlusion of the ICVA which blocks flow in both the PICA and lateral medullary penetrators.Here we describe 16 patients with acute infarcts in the ICVA territory in order to understand the role of the cerebellum and of the ICP in the occurrence of limb ataxia.     

单侧颈动脉闭塞脑梗死和侧支代偿情况分析

目的 通过计算机断层扫描（computer tomography,CT）和磁共振成像（magnetic resonance imaging,MRI）研究闭塞颈动脉同侧半球的梗死情况,分析不同侧支的代偿能力,增进我们对梗死机制的理解。方法 颈部血管彩色超声证实的43例单侧颈动脉闭塞患者,将颈动脉闭塞同侧的大脑半球分为大脑中动脉皮层区域、前皮层分水岭区域、后皮层分水岭区域、内分水岭区域、穿支动脉供血区域,比较各个解剖区域发生梗死情况,并分析侧支代偿种类和不同解剖部位梗死的关系。结果 颈动脉闭塞时,内分水岭区发生梗死最多见19例（44.2%）,8例前皮层分水岭梗死有6例伴有内分水岭区梗死。后交通动脉（posterior communicating artery,PCoA）出现是减少内分水岭区梗死的保护性因素[比值比（odd ratio,OR）为0.226,95%可信区间（confidence interval,CI）在0.058～0.833间,P =0.027]。结论 颈动脉闭塞时,内分水岭区发生梗死最多见,提示内分水岭区是对血流下降最敏感的区域。PCoA开放能够减少内分水岭区梗死。     

Clinical findings of intracranial vertebral artery disease using magnetic resonance angiography

The vertebral artery lesion has a variety of clinical characteristics. We sought to clarify the clinical patterns and the location of the intracranial vertebral artery (ICVA) diseases according to analyses of images obtained using magnetic resonance angiography (MRA). We studied vascular lesions, risk factors, symptoms, signs, and outcomes in 35 patients with ICVA disease (3 had bilateral occlusion; 9, unilateral occlusion; 6, bilateral stenosis; and 17, unilateral stenosis). The most common site of unilateral and bilateral lesions was the distal ICVA after the origin of posterior inferior cerebellar artery (PICA). We found accompanying basilar artery disease in 28.6% of patients with unilateral and bilateral ICVA disease. The majority of the ICVA lesions were associated with internal carotid arteries disease (48.8%). The common vascular risk factors were hypertension (71%), diabetes mellitus (34%), hyperlipidemia (31%), smoking (29%), and coronary artery disease (23%). Eighteen patients (51.4%) had transient ischemic attacks (TIAs) only, 10 patients (28.6%) had TIAs before stroke, and 5 patients (14.3%) had strokes without TIAs. Most patients (80%) with TIAs, with or without stroke, had multiple episodes. Vertigo or dizziness, ataxia, limbs weakness and abnormal gait were the common symptoms and signs. At 6 months follow-up, 66.7% patients had no symptoms or only slight symptoms that caused no disability. Our data showed (1) the usual location of ICVA disease (occlusion or severe stenosis) was distal to PICA, especially near the vertebrobasilar junction; (2) the risk factors were hypertension, diabetes mellitus, hyperlipidemia, smoking, and coronary artery disease; (3) patients with ICVA disease had a high frequency of accompanying internal carotid, middle cerebral, or basilar artery disease; (4) vertigo or dizziness, and ataxia were the common symptoms and signs; (5) TIA was the most common clinical pattern; (6) the outcome was favorable, except in cases with bilateral ICVA occlusion.     

Embolism from vertebral artery origin occlusive disease.

We report 10 patients with severe occlusive disease of the vertebral artery (VA) origin in the neck with intra-arterial embolism to the posterior circulation. The VA lesions in seven patients were complete occlusions, and three patients had severe atherostenosis. All patients had strokes in the vertebrobasilar territory. The most frequent recipient sites of intra-arterial embolism were the intracranial VA-posterior inferior cerebellar artery region (8), and the distal basilar artery (BA) and its superior cerebellar and posterior cerebral artery branches (7). Two patients had pontine infarction due to BA embolism. The most common clinical signs were due to cerebellar infarction. Atherosclerotic disease of the VA origin has features in common with disease of the internal carotid artery origin. Both have similar risk factors and demography, and each can cause strokes by intracranial intra-arterial embolism.     

Posterior cerebral artery territory infarcts in the New England Medical Center Posterior Circulation Registry.

BACKGROUND: Infarcts in the territory of the posterior cerebral arteries (PCAs) are common. Although associated clinical symptoms and signs are known, the mechanisms of stroke and the anatomical distribution of PCA territory lesions caused by the various stroke mechanisms are less well defined. Published reports have selected only special subgroups of patients. PATIENTS AND METHODS: We studied stroke mechanisms, infarct distribution, and clinical findings among 79 patients in the New England Medical Center Posterior Circulation Registry in whom brain imaging scans showed infarcts that involved 1 or more cortical territories of the PCA. RESULTS: Forty-eight patients (61%) had infarcts limited to the PCA territory (pure PCA), while 31 (39%) also had infarcts in other territories (PCA+). Infarcts were in the cortical territory of the PCA in 47 patients (59%) and were cortical and deep in 32 (41%). Infarcts that were cortical and deep were more common in PCA+ lesions. Stroke mechanisms were embolism of cardiac origin (32 [41%]), proximal arterial disease (25[32%]), cryptogenic embolism (8[10%]), intrinsic PCA disease (7[9%]), vasoconstriction (4[5%]), and coagulopathy (3[4%]). Patients with cardiogenic embolism and intrinsic PCA disease often had pure PCA territory infarcts, while patients with proximal arterial disease more often had PCA+ infarcts. Visual abnormalities were present in 66 patients (84%). Motor weakness, cognitive and behavioral abnormalities, and ataxia were found in 20 patients (25%); only 12 (15%) had sensory signs. CONCLUSIONS: The great majority of pure PCA and PCA+ territory infarcts are caused by cardiac or intra-arterial embolism. Intrinsic PCA disease, vasoconstriction, and coagulopathy are less common causes of infarction.     

Basilar artery occlusive disease in the New England Medical Center Posterior Circulation Registry

BACKGROUND: Most reports on basilar artery (BA) occlusive disease have retrospectively described single cases or small patient series. OBJECTIVE: To assess clinical and vascular features, stroke mechanisms, etiologies, and outcome of moderate to severe BA occlusive disease among 407 patients in the New England Medical Center Posterior Circulation Registry, the largest prospective series of consecutively collected patients with posterior circulation ischemia to date. RESULTS: We studied 87 patients and identified 3 patient groups with distinct vascular, clinical, etiological, and prognostic characteristics: isolated BA disease (39 patients [44.8%]), BA involvement as part of widespread posterior circulation atherosclerosis (36 patients [41.4%]), and embolism to the BA (12 patients [13.8%]). Vascular risk factors were common and often multiple. Most patients (54 [62.1%]) had involvement of the midportion of the BA. Fifty-eight patients (66%) initially had transient ischemic attacks, of whom 34 (58.6%) progressed to stroke. Transient ischemic attacks were usually multiple, lasted for several months, and increased in frequency as the stroke approached. When an infarct was present, the middle posterior intracranial territory was most often involved (66 patients [75.9%]). Outcome was much better than previously assumed. The mortality rate was 2.3%, and 62 patients (almost 75%) had minor or no deficits at follow-up. Outcome was best among patients with widespread atherosclerotic disease and worst in 7; (58.3%, with major disability) of 12 patients with embolism to the BA. Distal territory involvement, embolism, BA occlusion, decreased level of consciousness, tetraparesis, and abnormal pupils were significant predictors of poor outcome. CONCLUSION: Inclusion of patients into 1 of the BA groups and early identification of predictive outcome factors guide diagnostic evaluation and treatment.     

Chinese-white differences in the distribution of occlusive cerebrovascular disease

The distribution of cerebrovascular lesions is affected by race. Blacks and Japanese have more intracranial occlusive cerebrovascular disease, while whites have more extracranial disease. Despite a high incidence of stroke in China, there are few formal studies of the distribution of vascular occlusive disease in Chinese populations. We compared clinical and angiographic features of 24 white and 24 Chinese patients with symptomatic occlusive cerebrovascular disease. In symptomatic vascular territories, whites had more severe (greater than or equal to 50% stenosis) extracranial lesions, while Chinese had more severe intracranial lesions. When we counted mild and severe lesions in a symptomatic territory, whites had more extracranial lesions while Chinese had more intracranial lesions. When we combined symptomatic and asymptomatic territories, whites had more extracranial lesions, while Chinese had more intracranial lesions. White patients reported more transient ischemic attacks. The distribution of lesions, however, was not explained by differences in incidence of transient ischemia, hypertension, diabetes, hypercholesterolemia, or ischemic heart disease between the groups. The preponderance of intracranial vascular lesions in Chinese patients is similar to that seen in blacks and Japanese. Racial differences in the occurrence of extracranial and intracranial lesions raise the possibility of a different underlying pathophysiology for the 2 locations.     

Midbrain infarction: associations and aetiologies in the New England Medical Center Posterior Circulation Registry

Most reports of midbrain infarction have describedclinicoanatomical correlations rather than associations andaetiologies. Thirty nine patients with midbrain infarction (9.4%) aredescribed out of a series of 415 patients with vertebrobasilarischaemic lesions in the New England Medical Center PosteriorCirculation Registry. Patients were categorised according to therostral-caudal extent of infarction. The "proximal" vertebrobasilarterritory includes the medulla and posterior inferior cerebellar artery territory. The "middle" territory includes the pons and anterior inferior cerebellar artery territory. The "distal" territoryincludes the rostral midbrain, thalami, superior cerebellum, and medial temporal and occipital lobes. Midbrain infarction was accompanied by"proximal" territory infarcts in four patients, and by "middle" territory infarction in 19 patients. Thirteen patients had associated "distal" territory infarcts, three of whom had occipital ortemporal lobe infarcts. Only three patients had isolated midbraininfarcts. Cardioembolism (n=11), in situ thrombosis (n=9), large artery to artery embolism (n=7), and intrinsic branch penetrator disease (n=5)were the most common aetiologies. Bilateral infarction and accompanyingpontine infarction were associated with the most extensivevertebrobasilar occlusive disease. Midbrain infarction was 10-fold morelikely to be accompanied by ischaemia of neighbouring structures thanit was to occur in isolation. Recognition of the different patterns ofinfarction may act as a guide to the underlying aetiology and vascular lesions.

     

Anatomy of sensory findings in patients with posterior cerebral artery territory infarction.

BACKGROUND: Posterior cerebral arteries (PCAs) supply the ventrolateral thalamic sensory nuclei and white matter sensory tracts to the somatosensory parietal cortex. Patients with PCA territory strokes often have visual, memory, cognitive, and sensory signs. Clinicoanatomic correlation of visual, cognitive, and memory functions are well defined but, to our knowledge, no systematic study has analyzed the anatomy of sensory abnormalities. OBJECTIVE: To assess the frequency and anatomic correlation of sensory symptoms and signs in patients with PCA territory infarction. PATIENTS AND METHODS: Sixty patients with hemispheral and hemispheral and deep PCA territory infarcts apparent on computed tomographic and magnetic resonance imaging scans were studied for the presence of sensory findings and location of infarcts. RESULTS: Sensory symptoms or signs were present in 15 (25%) of 60 patients. Among patients with sensory findings, 11 of 15 had infarcts in the ventrolateral thalamus in the territory of the thalamogeniculate or lateral posterior choroidal arteries. The other 4 patients had no ventrolateral thalamic or white matter infarction but had severe proximal vascular occlusive lesions that could have caused temporary thalamic ischemia. One of these 4 patients had a medial thalamic infarct and transient hemisensory symptoms. Twelve patients had thalamic infarcts and no recorded sensory findings. Seven patients with thalamic infarcts (6 medial and 1 ventrolateral) had no sensory findings, and sensory findings could not be accurately assessed in 4 patients with ventrolateral and 1 patient with medial thalamic infarcts. CONCLUSIONS: All patients with PCA territory infarcts and sensory findings either had thalamic infarcts in thalamogeniculate or lateral posterior choroidal artery territory or had thalamic ischemia. Sensory findings in PCA territory infarction indicate ventrolateral thalamic ischemia.     

双侧小脑梗死模式的探讨

目的探寻双侧小脑梗死的模式和机制。方法经MRI弥散成像(DWI)证实急性期小脑梗死的患者,根据梗死灶的分布将患者分为单侧小脑梗死组(UCI)和双侧小脑梗死组(BCI),并对两组的人口学特征、血管分布、小脑以外梗死灶以及病因进行了比较。结果因急性卒中入院的115例后循环脑梗死患者中,56例为小脑梗死或小脑合并其它部位梗死,其中单侧小脑梗死36例(64.3%),双侧小脑梗死20例(35.7%)。基线资料比较显示,脑卒中史(P=0.002)、纤维蛋白元水平(P=0.036)和入院时NIHSS评分(P=0.001)在双侧小脑梗死组明显高于单侧小脑梗死组。按血管分布区划分,小脑后下动脉(PICA)供血区小脑梗死发生率最高,且更多发生单侧小脑梗死(P=0.006);而双侧小脑梗死更常见于PICA+小脑上动脉(SCA)供血区(P=0.004)。双侧小脑梗死组合并小脑以外梗死灶的发生率明显高于单侧小脑梗死组(P=0.002),特别是合并幕下梗死灶常见(P=0.022)。在卒中机制上,双侧小脑梗死以大动脉粥样硬化性病变更多见(P=0.041),责任动脉病变主要是在椎动脉V4段、V4段与BA接合处的重度狭窄或闭塞。结论双侧小脑梗死并不少见,常见于PICA+SCA供血区;大动脉粥样硬化所致动脉源性栓塞是其卒中重要机制之一。     

多灶性后循环缺血患者的病灶分布与血管形态异常及近期预后分析

目的 观察多灶性后循环缺血患者的病灶分布和血管形态异常的特点,评估患者出院时的近期预后及其与病灶分布和血管形态的关系.方法 对34例经过MR/所证实的多灶性后循环缺血患者行主动脉弓及全脑血管DSA,全面分析病灶分布及血管形态异常的特点;同时对患者出院时的近期预后用改良Rankin分级(MRS)评分表进行评估,分析病灶分布及血管形态异常与近期预后的关系.结果 多灶性后循环缺血患者最常被累及的部位是脑桥(22例),最常被累及的区段是中段+远段(12例);34例患者中有26例(76.5%)DSA显示出血管形态异常,最常被累及的动脉是椎动脉起始段(14例)和颅内段(13例)及基底动脉(7例);出院时7例患者(20.6%)存在预后不良,其中6例(17.6%)为重度残疾,1例(2.9%)死亡.近中远段同时受累和基底动脉受累的患者表现出预后不良.结论 血管形态异常是多灶性后循环缺血的重要病理基础和致病因素,病灶区段的分布和数目及血管受累部位是决定预后的关键因素.