Arterial pathology in cerebellar infarction

Bypass grafting to the third segment of the vertebral artery for symptomatic extensive vertebrobasilar atherosclerotic disease

Symptomatic vertebrobasilar atherosclerotic disease is rarely encountered but represents a high-risk factor for recurrent transient ischemic attack or stroke. Posterior strokes are usually associated with embolism or hemodynamic impairment. Extensive disease involving the V3 and V4 segments of the vertebral artery (VA) remains infrequent, and optimal management is limited owing to the infrequency of this disease. We illustrate the case of a 65-year-old man who presented with recurrent transient episodes of dizziness with acute onset of instability, nausea, and left visual blurring. Magnetic resonance imaging findings of the head were normal, and computed tomography angiography revealed severe atherosclerotic disease of both VAs, with proximal occlusion of the right VA and multiple tight stenoses of the left VA at the V1 and V4 segments. Duplex ultrasound found markedly reduced anterograde flow in the VAs and basilar arteries and nonsignificant stenosis of the internal carotid arteries. Optimal medical treatment led to a decrease of transient symptoms. However, the patient developed a cerebellar infarction in the left posteroinferior cerebellar artery territory with left VA V4 segment occlusion. Surgical revascularization of the right VA was decided by the multidisciplinary team. Through an anterolateral approach of the right VA V3 segment, revascularization was performed using a common carotid artery-to-right VA bypass using a reversed saphenous vein graft. The patient fully recovered and was free of symptoms during the next 14 months of follow-up. In the case of extensive VA occlusive disease, surgical reconstruction of the distal VA using a bypass from the common carotid artery represents an option to improve hemodynamics and/or eliminate an embolic source of posterior stroke on a case-by-case basis.

Vertebral Artery Stenosis: A Narrative Review

Vertebral artery stenosis (VAS) is the cause of approximately 20% of ischemic strokes in the posterior circulation. There are several causes of vertebral artery stenosis, including atherosclerosis, calcification, dissections, fibromuscular dysplasia, giant cell arteritis, neurofibromatosis type 1, and bony compressions. The most common cause of VAS is atherosclerosis which is derived from the macrophage-induced oxidation of low-density lipoproteins (LDLs), alongside the accumulation of cholesterol. Calcification of the vertebral artery occurs when there is excess calcium and phosphate deposition in the vessel. Dissection of the vertebral artery can lead to the formation of a hematoma causing stenosis of the vertebral artery. Fibromuscular dysplasia can result in stenosis due to the deposition of collagen fibers in the tunica media, intima, or adventitia. Giant cell arteritis, an autoimmune disorder, causes inflammation of the internal elastic membrane resulting in eventual stenosis of the artery. Neurofibromatosis type 1, an autosomal dominant disorder, results in the stenosis of the vertebral artery due to the altered function of neurofibromin. Mechanical compression of the vertebral artery by bone can also cause stenosis of the vertebral artery. Digital subtraction angiography (DSA) is considered the current gold standard in diagnosing vertebral artery stenosis; however, its associated morbidity and mortality have led to increased use of non-invasive techniques such as duplex ultrasonography (DUS), computed tomography angiography (CTA), and magnetic resonance angiography (MRA). Currently, asymptomatic and symptomatic vertebral artery stenoses are treated by risk factor modification and medical treatment. However, it is recommended that surgical (endarterectomy, reconstruction, and decompression) and endovascular (balloon coronary, bare-metal, and drug-eluting stents) treatments are also used for symptomatic vertebral artery stenosis.

Postpartum cerebral arterial dissections: Clinical features and treatment

Postpartum cerebral arterial dissections are rare, and the clinical features, diagnosis, and treatment approaches are not clear to many physicians. This study was to investigate the clinical features, diagnosis, and treatment of postpartum cerebral arterial dissections.One patient with postpartum cerebral arterial dissections enrolled in our hospital was analyzed. All patients with postpartum cerebral arterial dissections retrieved from the PubMed were also included in this study and analyzed.A total of 45 patients with postpartum cerebral arterial dissections were retrieved including our case, with an age range of 24 to 44 years (mean 34). Thirty-six (80%) patients were older than 30 years of age (mean 35). There were 17 cases of cesarean section, 14 cases of natural labor, and 14 cases whose delivery modes were not reported. The clinical symptoms included headache in 35 cases (78%) and neck pain in 14 (31%). The symptoms occurred at a mean time of 11 days (range 0-53 days) following delivery. Among 45 patients, arterial dissections involved unilateral carotid or vertebral artery in 29 cases (64%), bilateral carotid or vertebral arteries in 8 (18%), 3 arteries in 3 (7%), and all bilateral carotid and vertebral arteries in 5 (11%). Fourteen (31%) patients were treated with antiplatelet agents, 27 (60%) with anticoagulation, 7 (16%) with both antiplatelet and anticoagulation medications, and only 2 (4%) with stent angioplasty. The prognosis was complete recovery in 30 (86%) patients and mild focal neurological symptoms in 5 (14%).Postpartum cerebral arterial dissections are rare, and correct diagnosis relies on imaging examination. Prognosis is usually favorable in patients with early diagnosis and prompt treatment.

Patterns of ischemic posterior circulation strokes: A clinical, anatomical, and radiological review

Background

Posterior circulation and anterior circulation strokes share many clinical, pathogenetic and radiological features, although some clinical signs are highly specific to posterior circulation strokes. Arterial stenosis and occlusions occur in significant numbers in both acute posterior circulation and anterior circulation strokes, making them good candidates for endovascular treatment. Among posterior circulation strokes, basilar artery occlusions stand out because of the diagnostic and acute treatment challenges.

Methods

We reviewed the literature on clinical stroke syndromes and neuroimaging findings and systematically describe for each anatomical site of stroke the detailed clinical and radiological information (anatomical representation, diffusion weighted imaging and angiographic sequences). The principles of neuroimaging of posterior circulation strokes and the prognosis for each stroke localization are also discussed.

Review summary

Stroke syndromes in the territories of the vertebral, basilar, cerebellar, and posterior cerebral arteries are presented. Features typical of posterior circulation strokes are highlighted, including patterns of basilar artery occlusions. Clinical severity and prognosis of posterior circulation strokes are highly variable, and given that they are more difficult to detect on CT-based neuroimaging, magnetic resonance imaging is the technique of choice in suspected posterior circulation strokes. Rapid identification of arterial occlusion patterns may provide prognostic information and support acute revascularization decisions.

Conclusions

Posterior circulation stroke syndromes tightly reflect lesion localization and arterial occlusion patterns. Although many clinical and pathogenetic features are similar to anterior circulation strokes, notable differences exist in terms of clinical presentation, stroke mechanism, prognosis, and response to acute recanalization.

Predicting Surgical Intervention in Cerebellar Stroke: A Quantitative Retrospective Analysis

BACKGROUND

Debate still exists regarding whether preventive surgical decompression should be offered to high-risk patients experiencing cerebellar stroke. This study aimed to predict neurologic decline based on risk factors, volumetric analysis, and imaging characteristics.

METHODS

This retrospective cohort study comprised patients ≥18 years who presented with acute cerebellar ischemic stroke (CIS) between January 2011 and December 2016. Diagnostic imaging was used to calculate metrics based on individual stroke, cerebellar, and posterior fossa volumes. Head computed tomography scans on presentation and day of peak swelling were used to tabulate a CIS score.

RESULTS

The study included 86 patients; most were male and African American. Posterior inferior communicating artery stroke was most common (50%). On initial presentation imaging, 18.6% had documented hydrocephalus, 20.9% had brainstem compression, 22.1% had brainstem stroke, and 39.5% had stroke in another vascular territory. Cardioembolic stroke was the most common etiology, followed by cryptogenic stroke. Overall, patients who underwent surgical intervention had larger stroke volumes on presentation. Patients undergoing surgical intervention also experienced faster cerebellar swelling compared with patients without intervention. Total CIS scores were statistically significant and remained significant on the peak day of swelling. CIS score was independently associated with neurosurgical intervention; patients in this group with delayed interventions (median CIS score, 6; range, 4-8) later deteriorated and required emergent surgical decompression. Eleven patients without intervention had CIS score >6; 4 patients died of stroke complications.

CONCLUSIONS

Volumetric studies and CIS score are objective measures that may help predict decline on imaging before clinical deterioration.

Association between Leukoaraiosis and Symptomatic Intracranial Large Artery Stenoses and Occlusions: the Chinese Intracranial Atherosclerosis (CICAS) Study

Leukoaraiosis (LA) is frequently found in ischemic stroke patients, especially when those patients have intracranial atherosclerosis (ICAS). However, previous studies regarding an association of LA with cerebral large artery atherosclerosis showed conflicting results, and the relationship of LA with ICAS is uncertain. This study aimed to explore the association between LA and cerebral large artery atherosclerosis in Chinese patients with cerebral ischemia. Data were derived from the Chinese Intracranial Atherosclerosis (CICAS) study. Patients diagnosed with an ischemic stroke or transient ischemic attack (TIA) within 7 days of symptom onset were included. The analysis of magnetic resonance imaging (MRI) focused on severity of LA in periventricular and deep white matter; type of cerebral large artery stenosis; and the number, severity, and distribution of ICAS lesions. ICAS was defined as an occlusion or more than 50% stenosis of intracranial vessels on magnetic resonance angiography. Among 2420 patients included, distinct LA was observed in 898 (37.11%) patients, and the rate of LA increased significantly with an increased number of risk factors. Multivariate analysis revealed that LA was independently associated with ICAS (odds ratio [OR], 1.388; 95% confidence interval [CI], 1.132-1.702; P=0.0016). In the subgroup analysis of ICAS, LA was more frequently observed in multiple lesions (OR, 1.342; 95% CI, 1.060-1.699; P=0.0146), occlusive lesions (OR, 1.554; 95% CI, 1.214-1.998; P=0.0005), and lesions in the posterior circulation (OR, 1.360; 95% CI, 1.003-1.846; P=0.0481). In this nationwide prospective study, LA was associated with symptomatic ICAS, patients with multiple ICAS lesions, occlusive lesions, and atherosclerotic lesions in the posterior circulation were more likely to coexist with LA.

Association between etiology and lesion site in ischemic brainstem infarcts: a retrospective observational study

BACKGROUND AND PURPOSE

To assess the anatomical distribution of the ischemic strokes of the brainstem, the effect of anatomical distribution on clinical features and prognosis, and the association between etiology and anatomical involvement.

METHODS

A retrospective search of the patient database of our institution was performed for a total of 227 patients who were admitted to the Department of Neurology, Medical Faculty of Bezmialem Vakif University between January 2012 and September 2014. Patients with adequate diagnostic data and 3-month follow-up visit were included in the study.

RESULTS

Twenty-one (9%), 136 (60%), and 65 (29%) patients had an infarction only at the mesencephalon, pons, and medulla, respectively. However, a single patient (0.5%) had an infarction both at the mesencephalon and pons, 3 (1.5%) at the pons and medulla, and 1 (0.5%) at the mesencephalon, pons, and medulla. While anterior involvement was more common in the mesencephalon and pons, posterior and lateral involvement occurred more frequently in the medulla. Large arterial atherothrombosis was the predominant cause of the strokes in all anatomical sites, particularly in infarcts involving the pons. Cardioembolic events were more common in patients with mesencephalic infarcts. Also, ischemia due to dissection was more common in infarctions involving the medulla, especially the lateral medulla. In subjects with simultaneous infarcts at other sites in addition to the brainstem, there was a significantly higher co-occurrence of medullary infarcts with cerebellar infarcts, mesencephalic infarcts with posterior cerebral artery infarcts, and pons infarcts with anterior circulation and multiple infarcts.

CONCLUSION

Determination of risk factors and infarct localization as well as prediction of etiological parameters may assist in improving survival rates and therapeutic approaches.

Utility of Items of Baseline National Institutes of Health Stroke Scale as Predictors of Functional Outcomes at Three Months after Mild Ischemic Stroke

BACKGROUND

Predicting outcomes of acute stroke patients initially presenting with mild neurologic deficits is crucial in decision making regarding thrombolytic therapy. We examined the utility of individual National Institutes of Health Stroke Scale (NIHSS) score items or clusters of items as predictors of functional outcomes at 3 months after mild stroke.

METHODS

Using a multicenter stroke registry database, we identified patients with acute ischemic stroke who presented within 4.5 hours of symptom onset and had baseline NIHSS scores less than or equal to 5. Functional outcomes at 3 months were dichotomized as favorable (modified RankinScale [mRS] score 0 or 1) or unfavorable (mRS 2-6). Individual NIHSS items, clusters of items, and the total score were tested for their ability to predict outcomes in multivariable models. Area under the receiver operating characteristic curve (AUC) was used to assess model performance.

RESULTS

Of the 2209 patients who met eligibility criteria, 588 (26.6%) exhibited unfavorable functional outcomes at 3 months. Of the 15 items of the NIHSS, all except item 8 (sensory) and item 11 (extinction) were significantly associated with unfavorable functional outcomes in bivariate analysis (P's < .05). Among the multivariable models, the model with the total NIHSS score exhibited an AUC similar to that of the model with all NIHSS items in predicting functional outcomes (.758 [95% confidence interval .739-.775] versus .759 [.740-.776]; P = .75 for pairwise comparison).

CONCLUSIONS

Simply using the total NIHSS score was as effective as using all individual items in predicting outcomes of mild stroke patients.

The Usefulness of the TOAST Classification and Prognostic Significance of Pyramidal Symptoms During the Acute Phase of Cerebellar Ischemic Stroke

Cerebellar stroke is a rare condition with very nonspecific clinical features. The symptoms in the acute phase could imitate acute peripheral vestibular disorders or a brainstem lesion. The aim of this study was to assess the usefulness of the Trial of Org 10172 in Acute Stroke Treatment (TOAST) classification in cerebellar stroke and the impact of clinical features on the prognosis. We retrospectively analyzed 107 patients with diagnosed ischemic cerebellar infarction. We studied the clinical features and compared them based on the location of the ischemic lesion and its distribution in the posterior interior cerebellar artery (PICA), superior cerebellar artery (SCA), and anterior inferior cerebellar artery (AICA) territories. According to the TOAST classification, stroke was more prevalent in atrial fibrillation (26/107) and when the lesion was in the PICA territory (39/107). Pyramidal signs occurred in 29/107 of patients and were more prevalent when the lesion was distributed in more than two vascular regions (p = 0.00640). Mortality was higher among patients with ischemic lesion caused by cardiac sources (p = 0.00094) and with pyramidal signs (p = 0.00640). The TOAST classification is less useful in assessing supratentorial ischemic infarcts. Cardioembolic etiology, location of the ischemic lesion, and pyramidal signs support a negative prognosis.

Comparative effectiveness of standard care with IV thrombolysis versus without IV thrombolysis for mild ischemic stroke

Background

One third of patients presenting with initially mild strokes have unfavorable outcomes, and the efficacy of intravenous thrombolysis (IVT) in this population has not been proven. This study aimed to evaluate the comparative effectiveness of standard care with IVT versus without IVT in mild stroke patients.

Methods and Results

Using a multicenter stroke registry database, we identified patients with acute ischemic stroke who presented within 4.5 hours of symptom onset and had initial National Institutes of Health Stroke Scale scores ≤5. Multivariable logistic analysis and propensity score matching were used to adjust for baseline imbalances between the patients who did and did not receive IVT. Adjusted odds ratios and 95% CIs of IVT were estimated for 3‐month modified Rankin Scale scores of 0 to 1 and symptomatic. Of 13 117 patients with stroke who were hospitalized between April 2008 and May 2012, 1386 met the eligibility criteria, and 194 (14.0%) were treated with IVT. For a modified Rankin Scale of 0 to 1 at 3 months, the adjusted odds ratios were 1.96 (95% CI, 1.28 to 3.00; P=0.002) by multivariable logistic analysis and 1.68 (1.10 to 2.56; P=0.02) by propensity score matching analysis, respectively. There was a statistically nonsignificant excess of symptomatic hemorrhagic transformation (odds ratios=3.76 [0.95 to 16.42; P=0.06] and 4.81 [0.84 to 49.34; P=0.09]), respectively.

Conclusions

In this observational registry‐based study, standard care with IVT is more effective than not receiving IVT in mild ischemic stroke patients, and there is a statistically nonsignificant risk of symptomatic hemorrhagic transformation.

MRI-based Algorithm for Acute Ischemic Stroke Subtype Classification

Background and Purpose

In order to improve inter-rater reliability and minimize diagnosis of undetermined etiology for stroke subtype classification, using a stroke registry, we developed and implemented a magnetic resonance imaging (MRI)-based algorithm for acute ischemic stroke subtype classification (MAGIC).

Methods

We enrolled patients who experienced an acute ischemic stroke, were hospitalized in the 14 participating centers within 7 days of onset, and had relevant lesions on MR-diffusion weighted imaging (DWI). MAGIC was designed to reflect recent advances in stroke imaging and thrombolytic therapy. The inter-rater reliability was compared with and without MAGIC to classify the Trial of Org 10172 in Acute Stroke Treatment (TOAST) of each stroke patient. MAGIC was then applied to all stroke patients hospitalized since July 2011, and information about stroke subtypes, other clinical characteristics, and stroke recurrence was collected via a web-based registry database.

Results

The overall intra-class correlation coefficient (ICC) value was 0.43 (95% CI, 0.31-0.57) for MAGIC and 0.28 (95% CI, 0.18-0.42) for TOAST. Large artery atherosclerosis (LAA) was the most common cause of acute ischemic stroke (38.3%), followed by cardioembolism (CE, 22.8%), undetermined cause (UD, 22.2%), and small-vessel occlusion (SVO, 14.6%). One-year stroke recurrence rates were the highest for two or more UDs (11.80%), followed by LAA (7.30%), CE (5.60%), and SVO (2.50%).

Conclusions

Despite several limitations, this study shows that the MAGIC system is feasible and may be helpful to classify stroke subtype in the clinic.

Audiovestibular loss in anterior inferior cerebellar artery territory infarction: a window to early detection?

Acute audiovestibular loss is a common neurotological condition that is characterized by sudden onset of severe prolonged (lasting days) vertigo and hearing loss and is diagnosed by the presence of canal paresis to caloric stimulation and sensorineural hearing loss on pure tone audiogram. Before 2000, papers on anterior inferior cerebellar artery (AICA) territory infarction focused mostly on associated brainstem and cerebellar findings, without a detailed description of neurotological findings. Since 2000, several reports have demonstrated that acute audiovestibular loss is an important sign for the diagnosis of AICA territory infarction. To date, at least eight subgroups of AICA infarction have been identified according to the pattern of neurotological presentations, among which the most common pattern of audiovestibular dysfunction is the combined loss of auditory and vestibular functions. Because audiovestibular loss may occur in isolation before ponto-cerebellar infarction involving AICA distribution, audiovestibular loss may serve as a window to prevent the progression of acute audiovestibular loss into more widespread areas of infarction in posterior circulation (mainly in the AICA territory). Clinician should keep in mind that acute audiovestibular loss may herald impending AICA territory infarction, especially when patients had basilar artery occlusive disease presumably close to the origin of the AICA on brain MRA, even if other central signs are absent and MRI does not demonstrate acute infarction.

Histopathologic evaluation of basilar artery atherosclerosis

INTRODUCTION

There has been limited attention to pathological features of basilar artery atherosclerosis. It has been assumed that pathology of basilar artery atherosclerosis mimics that of other vascular beds.

METHODS

To define the nature of the basilar artery atherosclerotic lesions, we analyzed postmortem intracranial artery samples from eight subjects with history of stroke.

RESULTS

Atherosclerotic lesions were present in 7/8 arteries examined, with a mean estimated stenosis of 34%. Lumen thrombus with a disrupted fibrous cap was seen in 1 lesion; the remaining 6 lesions revealed a thick fibrous cap. Neovascularity and calcification were seen in 1 lesion and mild to moderate inflammation was seen in 3 lesions. Necrotic core was present in 4/7 lesions, and was associated with plaque rupture in the only disrupted lesion.

CONCLUSIONS

Basilar artery atherosclerotic lesions were relatively benign in this series of patients presenting with stroke. While confirmation is needed with larger sample size, the relative paucity of neovascularity suggests a possibly distinctive histopathological profile.

[Cerebellar infarction]

Cerebellar infarction can be difficult to diagnose because the clinical picture is often dominated by fairly non-specific symptoms, which are more indicative of a benign condition. When cerebellar infarction affects the brainstem, the semiology is richer, and pure cerebellar signs are rendered less important. A perfect knowledge of the organisation of the cerebellar artery territories is required, regardless of the infarct topography. This knowledge is essential for making an accurate diagnosis, understanding the mechanisms and organising a treatment plan. Clinical algorithms for the treatment of dizziness, headaches and vomiting would improve the selection of candidates for brain imaging. Thus, the early identification of patients with a high risk of subsequent deterioration would lead to a better prognosis in cases of cerebellar artery territory infarction.

Neurologic Findings of Craniovertebral Junction Disease

IN THIS REVIEW, we explain the origins of central cord syndrome and Bell's cruciate paralysis and the intricate detail of neural pathways located in this region and their influence on motor and sensory function. Although lesion studies and tract tracing studies on primates over the past 50 years refute the theory of a somatotopically organized corticospinal tract, this concept continues to pervade many neuroanatomic texts. We categorized the various pathologies of the craniovertebral junction and their unique neurologic presentations. New developments in the fields of neuroscience of spinal tract lesioning are also discussed.

The vertebral artery: a review of anatomical, histopathological and functional factors influencing blood flow to the hindbrain

An uncompromised blood flow to the brain is essential for normal neurological function. If the blood supply to the hindbrain, via the paired vertebral arteries, is reduced sufficiently, signs and symptoms of tertebrobasilar ischaemia may result. There are several factors that may cause a reduction in vertebral artery blood flow. These include exostoses, such as the retroarticular canal and lateral bridge of the atlas vertebra that may cause compression of the related part of the vertebral artery; or atherosclerosis of the artery wall occluding the vessel lumen. Functional factors, such as sustained end-of-range rotation of the cervical spine, may cause distortion of the vertebral artery in the suboccipital region, which may be reflected as decreased blood flow in the suboccipital and intracranial parts of the artery. A combination of such factors is likely to cause reduced blood flow to the hindbrain. It is the purpose of this review to highlight some of the factors that may compromise vertebral artery blood flow and, therefore, to provide some evidence on which to base our professional practice.

Infarcts in the posterior circulation territory in migraine. The population-based MRI CAMERA study

In a previous study, migraine cases from the general population were found to be at significantly increased risk of silent infarct-like lesions in the posterior circulation (PC) territory of the brain, notably in the cerebellum. In this study we describe the clinical and neuroimaging characteristics of migraine cases with and without aura and controls with PC lesions. In total, 39 PC infarct-like lesions represented the majority (65%) of all 60 identified brain infarct-like lesions in the study sample (n = 435 subjects with and without migraine). Most lesions (n = 33) were located in the cerebellum, often multiple, and were round or oval-shaped, with a mean size of 7 mm. The majority (88%) of infratentorial infarct-like lesions had a vascular border zone location in the cerebellum. Prevalence of these border zone lesions differed between controls (0.7%), cases with migraine without aura (2.2%) and cases with migraine with aura (7.5%). Besides higher age, cardiovascular risk factors were not more prevalent in cases with migraine with PC lesions. Presence of these lesions was not associated with supratentorial brain changes, such as white matter lesions. The combination of vascular distribution, deep border zone location, shape, size and imaging characteristics on MRI makes it likely that the lesions have an infarct origin. Previous investigators attributed cases of similar 'very small' cerebellar infarcts in non-migraine patients to a number of different infarct mechanisms. The relevance and likelihood of the aetiological options are placed in the context of known migraine pathophysiology. In addition, the specific involvement of the cerebellum in migraine is discussed. The results suggest that a combination of (possibly migraine attack-related) hypoperfusion and embolism is the likeliest mechanism for PC infarction in migraine, and not atherosclerosis or small-vessel disease.

New England Medical Center Posterior Circulation Stroke Registry II. Vascular Lesions

Among 407 New England Medical Center Posterior Circulation Registry (NEMC-PCR) patients, the extracranial (ECVA) and intracranial vertebral arteries (ICVA) were the commonest sites of severe occlusive disease followed by the basilar artery (BA). Severe occlusive lesions were found in >1 large artery in 148 patients; 134 had unilateral or bilateral severe disease at one arterial location. Single arterial site occlusive disease occurred most often in the ECVA (52 patients, 15 bilateral) followed by the ICVA (40 patients, 12 bilateral) and the BA (46 patients). Involvement of the ICVAs and the BA was very common and some patients also had ECVA lesions. Hypertension, smoking, and coronary and peripheral vascular disease were most prevalent in patients with extracranial disease while diabetes and hyperlipidemia were more common when occlusive lesions were only intracranial. Intra-arterial embolism was the most common mechanism of brain infarction in patients with ECVA and ICVA occlusive disease. ICVA occlusive lesions infrequently caused infarction limited to the proximal territory (medulla and posterior inferior cerebellum). BA lesions most often caused infarcts limited to the middle posterior circulation territory (pons and anterior inferior cerebellum). Posterior cerebral artery occlusive lesions were predominantly embolic. Penetrating artery disease caused mostly pontine and thalamic infarcts. Prognosis was poorest in patients with BA disease. The best prognosis surprisingly was in patients who had multiple arterial occlusive lesions; they often had position-sensitive transient ischemic attacks during months or years.

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.

Cerebellar infarction in adolescent males associated with acute marijuana use

OBJECTIVE

To demonstrate the clinical characteristics, radiologic findings, and neuropathological features of tetrahydrocannabinol-related posterior fossa ischemic stroke in adolescent patients.

DESIGN

A retrospective case and chart review of 3 cases encountered at a tertiary care institution over a span of 5 years.

SETTING

Inpatient and intensive care hospitalization units managing children and adolescents.

SUBJECTS

Male adolescent patients with ischemic cerebellar stroke after use of marijuana. DIAGNOSTIC INVESTIGATIONS: Computed tomography brain scans (3 subjects), magnetic resonance imaging brain study (1 subject), cerebral arteriography (1 subject), cerebellar biopsy (1 subject), and necropsy (2 subjects).

RESULTS

Three adolescent males had similar presentations of headache, fluctuating level of consciousness or lethargy, visual disturbance, and variable ataxia after self-administration of marijuana. They developed primary cerebellar infarctions within days after the exposure that could not be attributed to supratentorial herniation syndromes and only minimally involved brainstem structures.

CONCLUSIONS

Episodic marijuana use may represent a risk factor for stroke in childhood, particularly in the posterior circulation. Early recognition of the cerebellar stroke syndrome may allow prompt neurosurgical intervention, reducing morbidity.

Management of Acute Cerebellar Infarction: One Institution's Experience

OBJECTIVE

The management of cerebellar infarctions is controversial. The aim of this study was to determine which patients require surgical treatment and which surgical procedure should be performed when a patient with a cerebellar infarction exhibits progressive neurological deterioration.

METHODS

A total of 44 patients (24 male and 20 female patients; average age, 56 yr) were treated at our institution for cerebellar infarctions in the past 8 years. Twenty-five patients received conservative treatment; two patients who were deeply comatose received no treatment. The remaining 17 patients underwent emergency surgery. Of those 17 patients, 8 underwent external ventricular drainage alone, 5 underwent external ventricular drainage as the first treatment plus secondary suboccipital craniectomy, and 4 underwent suboccipital craniectomy, with removal of necrotic tissue, as the first treatment.

RESULTS

Of the 25 conservatively treated patients, 20 experienced good outcomes, 4 experienced moderate outcomes, and 1 died as a result of pulmonary embolism. Of the 17 surgically treated patients, 10 experienced good functional recoveries (7 treated with external ventricular drainage only and 3 treated with drainage followed by suboccipital craniectomy) and 3 survived with mild neurological deficits (one patient underwent ventriculostomy, one suboccipital craniectomy plus external ventricular drainage, and one suboccipital craniectomy only). The overall mortality rate was 13.6% (6 of 44 patients).

CONCLUSION

For patients with worsening levels of consciousness and radiologically evident ventricular enlargement, we recommend external ventricular drainage. We reserve surgical resection of necrotic tissue for patients whose clinical status worsens despite ventriculostomy, those for whom worsening is accompanied by signs of brainstem compression, and those with tight posterior fossae.

Vertebral artery atherosclerosis: a risk factor in the use of manipulative therapy?

BACKGROUND AND PURPOSE

Vertebrobasilar insufficiency, a direct result of compromised blood flow in the vertebrobasilar circulation, may be caused by stretching and/or compression of the vertebral arteries, particularly if superimposed on underlying atherosclerosis of the vessels. This is an important consideration when using manipulative therapy techniques. The aim of the present study was to investigate the incidence of atherosclerosis and to calculate the relative associated decrease in blood flow in the third and fourth parts of the vertebral artery, in a sample of the adult population.

METHOD

A laboratory-based experimental investigation was used to study 362 vertebral arteries from embalmed adult cadavers that were routinely processed for light microscopic study. The incidence of each grade of atherosclerosis in the vessels was recorded. Atherosclerosis was classified as grades 0-5, where Grade 0 represented no atherosclerosis and Grade 5 a fully developed plaque occluding more than 75% of the vessel lumen. From mean measurements of 188 of these arteries, the estimated decrease in luminal cross-sectional area and the relative decrease in blood flow in the atherosclerotic vessels were calculated.

RESULTS

The highest incidence of atherosclerosis found was Grade 3 (third part of the vertebral artery (VA3): 42.0%; fourth part of the vertebral artery (VA4): 35.2%). An estimated decrease in artery luminal cross-sectional area to 6.2% of normal in Grade 5 atherosclerosis was found. Because blood flow is proportional to the fourth power of the vessel radius, relative decreases in blood flow in grades 1-5 atherosclerosis from 100% to 0% (with critical closing pressure in vessels), respectively, are likely to occur.

CONCLUSIONS

These data suggest that, as significant numbers of the sample showed marked (Grade 3+) atherosclerosis, concomitant with decreased blood flow in the vertebral arteries, this population is at risk for developing vertebrobasilar insufficiency. Because other Western populations may be similarly at risk, particular care should be taken when considering the use of rotational manipulative therapy techniques in treatments of the cervical spine.

Bilateral vertebral artery occlusion resulting from giant cell arteritis: report of 3 cases and review of the literature

Giant cell arteritis (GCA) is known to affect the extracranial part of the vertebral arteries. Bilateral vertebral artery occlusion (BVAO) is a rare but serious neurologic condition. We report 3 patients with autopsy-proven (2 patients) or clinically diagnosed (1 patient) GCA causing BVAO. A review of the literature concerning BVAO revealed 5 other cases of BVAO resulting from GCA and 110 cases with underlying arteriosclerotic disease. Our 3 patients (mean age, 66 yr; range, 60-78 yr) with BVAO resulting from GCA all had initial severe headache followed by the onset of stepwise progressive, partly side-alternating neurologic deficits due to bilateral infarctions in the vertebrobasilar circulation territory. This course, more accelerated in BVAO due to GCA than in BVAO of arteriosclerotic origin, seems to be a typical, if not particular, clinical syndrome. BVAO was the first clinical manifestation of GCA in 1 of our patients and in 1 published case. From a clinical view, BVAO resulting from GCA differs from BVAO of arteriosclerotic origin by the much higher mortality rate (75% versus 19%, respectively), the presence of headache (100% versus 22%), fever (50% versus 0%), and elevated erythrocyte sedimentation rate (ESR in all GCA cases >45 mm/h; no data in the arteriosclerotic patient group), but not by the neurologic signs themselves. Therapy of BVAO resulting from GCA is purely empiric. In view of the serious prognosis, we propose treatment with intravenous high-dose glucocorticoids and additional immunosuppression with cyclophosphamide; the use of anticoagulation depends on the individual patient's estimated risk-benefit profile. Although BVAO due to GCA is rare, physicians and especially rheumatologists or neurologists should be aware of this entity because of its high mortality in patients without immediate introduction of a high-dose immunosuppressive therapy. Suspicion of GCA should arise in a patient aged over 50 years with no other vascular risk factors suffering from bilateral symptoms of ischemia in the vertebrobasilar territory, with a quickly progressing stepwise course and with headache, fever, or history of myalgia. ESR and temporal artery biopsy should be performed without delay. Early diagnosis of GCA is necessary for immediate initiation of intensive antiinflammatory and immunosuppressive treatment, without which progressive deterioration and systemic involvement are likely to be fatal.

Superior cerebellar artery territory stroke

OBJECTIVES

The purpose of this study was to clarify etiologic factors, prior symptoms and clinical features of isole superior cerebellar artery (SCA) territory infarcts.

METHODS

All data were collected from consecutive 21 patients with isole SCA infarcts involved on computerized tomography.

RESULTS

The risk factors including hypertension, cardiopathy and rhythm disturbances, hyperlipidemia, diabetes mellitus, abnormality in homeostasis, smoking, oral contraceptive have been identified. Headache, nausea-vomiting, vertigo, gait imbalance and diplopia were the most common complaints at onset. During the clinical course, the most common findings have been found as dysmetria and dysdiadochokinesia, dysarthria, ataxia and vertigo. Although 19 patients were improved in different degrees, 2 patients died because of cardiorespiratory arrest. Classical syndrome of SCA was only seen in 2 patients.

CONCLUSION

According to our findings, SCA territory infarcts have multiple risk factors, and various clinical features as well as the syndrome of SCA are usually rare and incomplete.

Hypoplasia, stenosis and other alterations of the vertebral artery: does impaired blood rheology manifest a hidden disease?

OBJECTIVES

The clinical relevance of abnormal vessel findings in the posterior circulation is still a matter of controversy.

PATIENTS AND METHODS

We compared 48 patients displaying sonographic abnormalities of one vertebral artery, i.e., vertebral artery hypoplasia in 24 cases, stenosis in 13 cases, plaques in 11 cases, with 25 healthy subjects in terms of whole blood viscoelasticity and plasma viscosity.

RESULTS

All patients with stenosis and plaques suffered from clinical signs and symptoms of ischemic cerebrovascular disease, predominantly in the posterior circulation. Free of acute clinical symptoms were 5 of the 24 patients with hypoplasia. Highly statistically significant differences in blood viscoelasticity were found between the patients and the healthy subjects. As regards differences between the groups, whole blood viscoelasticity was most impaired in stenosis, shear resistance was significantly higher in stenosis compared to hypoplasia. Symptom-free patients with one-sided vertebral artery hypoplasia had a significantly better, nearly normal blood rheology at a low shear rate (10/s), compared to clinically symptomatic patients with hypoplasia.

CONCLUSION

The results of the present study offer some evidence that altered hemorheology may be associated with symptomatic vertebrobasilar occlusive disease.

Bilateral anterior inferior cerebellar artery territory infarcts

Bilateral anterior inferior cerebellar artery (AICA) territory infarcts are rare. Their occurrence usually signifies severe intracranial vertebrobasilar disease. Unlike head computed tomography, magnetic resonance (MR) imaging reveals these infarcts clearly and MR angiography allows the intracranial vasculature to be defined noninvasively. We now report a patient with bilateral AICA territory infarcts.

Spontaneous cerebellar strokes. Clinical observations in 60 patients

This is a retrospective study carried out by clinical analysis of the authors' experience in 60 patients with cerebellar strokes--of which 39 were spontaneous cerebellar hemorrhage and 21 were cerebellar infarction--to compare the clinical presentation, course, and prognosis. Hypertension was found to be the most important etiologic factor. Clinical differentiation of cerebellar hemorrhage from infarction was not possible, but the management was similar in both entities. Computerized tomography was necessary to make diagnosis of the stroke mechanism. In evaluating outcome, the authors conclude that the most important single factor affecting the prognosis was the early correct diagnosis.

Multiple acute infarcts in the posterior circulation

OBJECTIVE

to evaluate clinical, radiological, and prognostic features of patients with multiple acute infarcts in remote arterial territories of the posterior circulation.

DESIGN

Data analysis from a prospective acute stroke registry in a community based primary care centre using a standard protocol including MRI and MRA.

RESULTS

In three and a half years, 27 of the 236 patients (11%) with posterior circulation stroke had multiple acute infarcts in the posterior circulation as shown by gadolinium enhancement on MRI. Eighteen patients had multiple infratentorial and supratentorial infarcts including the cerebellum and posterior cerebral artery territory, with coexisting brainstem involvement in seven patients. Fourteen patients had a rostral basilar artery syndrome and cerebellar signs; four patients had a visual field defect with cerebellar signs. Causes were vertebral (six) or basilar (four) artery atheromatosis, and cardioembolism (four). Seven patients had multiple acute infarcts in the posterior circulation of the cerebellum and lower brainstem. Brainstem and cerebellar signs were found in most patients (five); aetiologies were small vessel disease (four), cardioembolism (one), and vertebral artery dissection (one). Two patients with large artery atheromatosis had multiple acute infarcts in the posterior circulation in the brainstem and posterior cerebral artery territory. One month after stroke more than 25% of the patients were dependent or had died. There was no difference in the outcome between the three groups, and recovery was linked to the size of infarcts rather than to a high number of infarcts.

CONCLUSIONS

multiple acute infarcts in the posterior circulation usually involve the cerebellum. Simultaneous brainstem and posterior cerebral artery territory infarcts sparing the cerebellum are uncommon. They can be suspected clinically before neuroimaging, mainly when supratentorial and infratentorial infarcts coexist. This may be important, because different patterns of infarction are associated with different causes of stroke.

The anatomical basis for the cerebellar infarcts

BACKGROUND

Very little can be found in the literature concerning the variation of the irrigation area of the cerebellar arteries, as well as the characteristics of anastomoses among these vessels. The anatomical features may determine certain features of cerebellar infarcts. Consequently, we examined the irrigation area of and the anastomoses among the cerebellar arteries.

METHODS

The anatomical features of the posterior inferior cerebellar artery (PICA), the anterior inferior cerebellar artery (AICA), and the superior cerebellar artery (SCA) were studied in 26 cerebella injected with india ink, while their irrigation areas and anastomoses were examined in 8 of these cerebella.

RESULTS

The PICA, which most often (82%) arose from the vertebral artery, was found most commonly (81.3%) to supply the largest part of the occipital surface of the cerebellar hemisphere, the caudal or caudomedial part of the tentorial surface, and the inferior vermis. The AICA, which usually (92%) arose from the basilar artery, commonly (68.8%) supplied most of the petrosal surface of the hemisphere and the flocculus. The SCA, which divided into the medial and the lateral trunks, always irrigated most of the tentorial surface of the cerebellum, the superior vermis, and the dentate nucleus. The PICA, AICA, and SCA were always interconnected by anastomoses, which ranged from 40 microns to 420 microns in diameter.

CONCLUSIONS

Cerebellar infarcts were documented by computed tomography (CT) or magnetic resonance imaging (MRI) examinations in 10 patients. The infarcts were located in the PICA territory (60%) or the SCA region (40%). The authors compared the obtained anatomic data to the features of the cerebellar infarcts in these patients.

Posterior circulation infarction: anatomy, pathophysiology, and clinical correlation

Posterior circulation cerebrovascular disease may be responsible for clinical syndromes that are determined by the vascular territory affected. An anatomic/topographic approach to the brain stem and cerebellum, relating the cross-sectional and functional anatomy to the vascular supply territories, is useful in the analysis of imaging studies of patients with posterior circulation cerebrovascular disease. Knowledge of the typical vascular distributions may be particularly useful for cases that do not show the classical clinical brain stem and cerebellar infarction syndromes. This approach may serve to improve our understanding of cerebrovascular disease in the posterior fossa.

Isolated lateropulsion of the trunk in cerebellar infarct

MRI in a 63-year-old male with isolated lateropulsion of the trunk disclosed an infarct in the inferior portion of the right cerebellar hemisphere, suggesting an end-zone type infarct in the lateral branch of the right posterior inferior cerebellar artery (1PICA) or a borderzone infarct between 1PICA and superior cerebellar artery. A close clinico-topographical relationship between isolated lateropulsion of the trunk and lesion in the territory of 1PICA was demonstrated.

Microvascular anatomy of the anterior surface of the medulla oblongata and olive

The arterial supply and the microanatomy of the anterior surface of the medulla oblongata and olive were studied in 11 cadaveric specimens, with investigation of the size, course, and length of the arteries. Two distinct anatomical entities divide the vascular supply in this region: 1) the pyramid, which is the anterior surface of the medulla; and 2) the olive, which is adjacent to the lateral aspect of the pyramid. Primary vascularization of the pyramid was via small branches of the anterior spinal artery, a branch of the vertebral artery. Minute perforators from the anterior spinal artery were found in all specimens. Arterial supply to the olive varied by location: its anterior aspect was primarily supplied by the anterior spinal artery; the upper portion of the posterior aspect of the olive was supplied by the vertebral artery, the anterior inferior cerebellar artery, and the basilar artery; and the middle and lower portions of the posterior aspect were fed by the vertebral artery and posterior inferior cerebellar artery. These arteries supplied the medulla through the small branches directed toward the olive. The authors observed a wide anastomotic net connecting the small arteries in this area. These patterns of microvascular supply of the pyramid and olive may deepen the understanding of clinical and pathological conditions resulting from arterial occlusion. The existence of an anastomotic net may account for the rare incidence of medullary infarction in the olive region.

The clinical and topographic spectrum of cerebellar infarcts: a clinical-magnetic resonance imaging correlation study

We studied 34 consecutive patients with non-mass-producing cerebellar infarcts using a standard protocol of investigations including magnetic resonance imaging (MRI). We analyzed the topography of infarcts to determine the involved arterial territories and we correlated the findings with neurological dysfunction and potential causes of stroke. Sixteen patients had an infarct in the territory of the posterior inferior cerebellar artery (PICA); 2, in the territory of the anterior inferior cerebellar artery (AICA); 13, in the territory of the superior cerebellar artery (SCA); and 8 had junctional infarcts between the territories of the medial and lateral branches of the PICA or PICA/SCA territories. PICA or medial PICA territory infarcts were manifested by acute vertigo and truncal ataxia, while the patients with lateral PICA territory infarcts presented with unsteadiness, limb ataxia and dysmetria without dysarthria. Patients with infarcts in the AICA territory were characterized by limb and trunk ataxia associated with signs of lateropontine involvement. Patients with SCA territory infarcts presented with dysarthria, unsteadiness and/or vertigo, limb ataxia, and dysmetria. Cardiac embolism was the main cause of large infarcts in the territories of the PICA (8/16) or SCA (4/7). Multiple small infarcts were associated with vertebrobasilar atherosclerosis (8/12). These clinical-MRI correlations allow better definition of the topographic and etiological spectrum of cerebellar infarction, which was previously based on pathological studies in subjects with severe infarction.