Anterior Cerebral Circulation Research Articles

Simplified Azygos Anterior Cerebral Bypass

Trapping with distal revascularization is a therapeutic option for giant aneurysms that cannot be clipped or coiled. In skull base lesions such as meningiomas, arterial encasement is often present, requiring, in some cases, revascularization procedures: extracranial-to-intracranial bypass and more recently intracranial-to-intracranial techniques. These techniques are used only in exceptional cases of tumors in other localizations. We report a case of a recurrent malignant frontal falx meningioma with encasement of both pericallosal arteries (PcaAs). During resection of the lesion, the left PcaA was sectioned and the right PcaA was occluded for manipulation and coagulation of the tumor. The occlusion was diagnosed with indocyanine green videoangiography. A Y-shaped superficial temporal artery graft was obtained in the right side, and the anterior cerebral artery circulation was reconstructed using an intracranial-to-intracranial bypass in the following fashion: right A2 to superficial temporal artery Y-shaped graft for both PcaAs. The patient's postoperative period was uneventful with no deficit, and the computed tomography angiography showed the preservation of both PcaAs. To the best of our knowledge, this microsurgical reconstruction of the PcaAs has not been performed before in a meningioma or a complex aneurysm case. We think the use of a superficial temporal artery as an in situ graft is more straightforward compared with other interposition grafts such as the radial artery graft or saphenous vein graft. The use of intracranial-to-intracranial techniques is the proper evolution of the use of classic extracranial-to-intracranial cerebral revascularization techniques.

Humo en el cerebro, síndrome de moyamoya en anemia de células falciformes: presentación de caso

El síndrome de moyamoya es una rara entidad oclusiva que afecta los vasos cerebrales. Es predominante de la población japonesa, de donde se creía inicialmente era exclusiva; pero hoy en día se han reportado casos en todo el mundo y en diferentes grupos étnicos. Consiste en la oclusión crónica y progresiva de la circulación cerebral anterior con la consecuente aparición de colaterales que da un patrón imaginológico en arteriografía, similar a una “nube de humo”; de ahí su nombre en japonés moyamoya. En este artículo se reporta el caso de un paciente pediátrico femenino de raza negra con antecedente de anemia de células falciformes con imágenes representativas.

Trevo versus Solitaire a Head‐to‐Head Comparison Between Two Heavy Weights of Clot Retrieval

Recent reports have indicated that mechanical thrombectomy may have potential to treat acute ischemic stroke. However, few comparative studies of neurothrombectomy devices are reported. This study aims to compare the safety and effectiveness of two retrievable stent systems in acute ischemic stroke patients. A prospective study comparing the clinical, radiological, and functional outcome of 33 patients with an angiographically verified occlusion of the anterior cerebral circulation. Patients were treated either with Trevo Retriever(TM) or Solitaire Stent(TM) according to the neurointerventionalist preference. Successful recanalization was defined as TICI grade 2a to 3. Good outcome was defined as a modified Rankin Scale score ≤ 2 at 3 months. Revascularization was achieved in 10 patients (77%) in the Trevo group and in 12 (60%) of the Solitaire group (P = .456). Rate of symptomatic ICH was 0% for Trevo versus 15% for Solitaire (P = .261). Four patients (30%) died during the 3-month follow-up period in the Trevo versus 5 patients (25%) in the solitaire group (P = 1.000). Rate of good outcome was 38% and 40% for Trevo and Solitaire respectively (P = .435). Our study showed no significant differences between both stentrievers. Moderately high recanalization rates are possible with both, however larger series may depict safety-related variations.

Initial Experience of a Novel Sheath Guide for Transbrachial Coil Embolization of Cerebral Aneurysms in the Anterior Cerebral Circulation

The transfemoral approach is a common technique for coil embolization of cerebral aneurysms in the anterior cerebral circulation. However, it is difficult to advance a guiding catheter into the carotid artery via the femoral route in patients with a tortuous aortic arch, an unfavorable supra-aortic takeoff, aortic diseases, or occlusion of the femoral artery. To report our initial experiences of coil embolization of cerebral aneurysms in the anterior cerebral circulation with a novel sheath guide for transbrachial carotid cannulation. A sheath guide designed specifically for transbrachial carotid cannulation was developed; transbrachial coil embolization for cerebral aneurysms began in May 2011. Included for analysis were patients who underwent transbrachial coil embolization for cerebral aneurysms in the anterior cerebral circulation from May 2011 to January 2012. Adjuvant techniques, angiographic results, procedural success, and periprocedural complications were investigated. Ten patients underwent transbrachial coil embolization of cerebral aneurysms in the anterior cerebral circulation. All procedures were successful using the brachial route. No periprocedural complications occurred. Patients were permitted to get seated immediately after coil embolization even during hemostasis. The sheath guide specifically designed for transbrachial carotid cannulation was useful for coil embolization of cerebral aneurysms in the anterior cerebral circulation.

Vascular distribution of stroke and its relationship to perioperative mortality and neurologic outcome after thoracic endovascular aortic repair

This study assessed the vascular distribution of stroke after thoracic endovascular aortic repair (TEVAR) and its relationship to perioperative death and neurologic outcome. A retrospective review was performed for patients undergoing TEVAR between 2001 and 2010. Aortic arch hybrid and abdominal debranching cases were excluded. Demographics, operative variables, and neurologic complications were examined. Stroke was defined as any new focal or global neurologic deficit lasting>24 hours with radiographic confirmation of acute intracranial pathology. Perioperative stroke occurred in 20 of 530 patients (3.8%) undergoing TEVAR. The cohort was 55% male and a mean age of 75.2±8.9 years (range, 57-90 years). Among patients with perioperative strokes, the indication for surgery was degenerative aneurysm in 14 (mean diameter, 6.8 cm), acute type B dissection in four, penetrating atherosclerotic aneurysm in one, and aortic transection in one. Cases were performed urgently or as an emergency in 60%. The proximal landing zone was zone 2 in 11 or zone 3 in nine. All strokes were embolic. The vascular distribution of stroke involved the anterior cerebral (AC) circulation in eight (zone 2, n=5) and the posterior cerebral (PC) circulation in 12 (zone 2, n=6). Laterality of cerebral infarction included five right-sided, eight left-sided, and seven bilateral strokes. Nine strokes were diagnosed<24 hours after operation. There was no difference in baseline demographics, aortic pathology, acuity, zone coverage, preoperative left subclavian artery revascularization, number of stents, or estimated blood loss between stroke groups based on vascular distribution. Independent risk factors for any perioperative stroke were chronic renal insufficiency (odds ratios [OR], 4.65; 95% confidence interval [CI], 1.22-17.7; P=.02) and history of prior stroke (OR, 4.92; 95% CI, 1.69-14.4; P=.004); the risk factor for AC stroke was prior stroke (OR, 7.67; 95% CI, 1.25-46.9; P=.03) and the risk factors for PC stroke were age (OR, 1.11; 95% CI, 1.00-1.23; P=.04), prior stroke (OR, 7.53; 95% CI, 1.78-31.8; P=.006), zone 2 coverage (OR, 6.11; 95% CI, 1.15-32.3; P=.03), and penetrating atherosclerotic ulcer (OR, 32.7; 95% CI, 1.33-807.2; P=.03). Overall in-hospital mortality was 20% (n=4), with those sustaining PC strokes observed to trend toward increased mortality (33% vs 0%; P=.12). Patients with AC strokes were more likely than those with PC strokes to achieve complete recovery of neurologic deficits before discharge (75% vs 17%; P=.02). Perioperative stroke after TEVAR is primarily an embolic event. Although infrequent, stroke was associated with significant morbidity and death, particularly among those with strokes involving the PC circulation.

Differential blood flow responses to CO2 in human internal and external carotid and vertebral arteries

Arterial CO2 serves as a mediator of cerebral blood flow(CBF), and its relative influence on the regulation of CBF is defined as cerebral CO2 reactivity. Our previous studies have demonstrated that there are differences in CBF responses to physiological stimuli (i.e. dynamic exercise and orthostatic stress) between arteries in humans. These findings suggest that dynamic CBF regulation and cerebral CO2 reactivity may be different in the anterior and posterior cerebral circulation. The aim of this study was to identify cerebral CO2 reactivity by measuring blood flow and examine potential differences in CO2 reactivity between the internal carotid artery (ICA), external carotid artery (ECA) and vertebral artery (VA). In 10 healthy young subjects, we evaluated the ICA, ECA, and VA blood flow responses by duplex ultrasonography (Vivid-e, GE Healthcare), and mean blood flow velocity in middle cerebral artery (MCA) and basilar artery (BA) by transcranial Doppler (Vivid-7, GE healthcare) during two levels of hypercapnia (3% and 6% CO2), normocapnia and hypocapnia to estimate CO2 reactivity. To characterize cerebrovascular reactivity to CO2,we used both exponential and linear regression analysis between CBF and estimated partial pressure of arterial CO2, calculated by end-tidal partial pressure of CO2. CO2 reactivity in VA was significantly lower than in ICA (coefficient of exponential regression 0.021 ± 0.008 vs. 0.030 ± 0.008; slope of linear regression 2.11 ± 0.84 vs. 3.18 ± 1.09% mmHg−1: VA vs. ICA, P <0.01). Lower CO2 reactivity in the posterior cerebral circulation was persistent in distal intracranial arteries (exponent 0.023 ± 0.006 vs. 0.037 ± 0.009; linear 2.29 ± 0.56 vs. 3.31 ± 0.87% mmHg−1: BA vs. MCA). In contrast, CO2 reactivity in ECA was markedly lower than in the intra-cerebral circulation (exponent 0.006 ± 0.007; linear 0.63 ± 0.64% mmHg−1, P <0.01). These findings indicate that vertebro-basilar circulation has lower CO2 reactivity than internal carotid circulation, and that CO2 reactivity of the external carotid circulation is markedly diminished compared to that of the cerebral circulation, which may explain different CBF responses to physiological stress.

Surgical treatment of anterior clinoidal meningiomas

Objective To investigate the surgical strategies and microsurgical techniques for anterior clinoidal meningiomas(ACMs).Methods A retrospective analysis of the clinical,radiographic,operative,and follow - up data was performed in 49 patients with ACMs who underwent surgical resection in our department between January 2000 to June 2011.Results The mean size of the tumors was 4.4 cm (range 2 ～7 cm).Simpson grade Ⅰ resection was achieved in 3 cases(6％ ),grade Ⅱ in 25(51％ ),grade Ⅲ in 12(25％ )and grade Ⅳ in 9 (18％).The mean follow- up period was 31.1months (ranged from 3 to 111months).Among the 30 patients with preoperative visual impairment,the visual acuity was improved in 12 cases (40％),unchanged in 15 ( 50％ ) and worsened in 3 ( 10％ ).New permanent postoperative neurological deficits were observed in 10 cases:1patient with new visual deficit,3 worsening of preexisting visual deficits,4 hemiparesis and 2 partial oculomotor nerve paresis.Conclusions ACMs consistently involve the unilateral arteries of the anterior cerebral circulation and optic apparatus.Constant microsurgical surveillance of the arterial tree and maintenance of the cerebrospinal fluid interface between the tumor and involved arteries and nerves are the most important operative nuances for safe tumor resection. Key words: Meningioma; Sphenoid wing; Anterior clinoidal process; Microsurgery

Are impaired endothelial function in the posterior cerebral circulation and intact endothelial function in the anterior cerebral and systemic circulation associated with migraine: A post hoc study

Summary It seems that migraine patients might suffer from localized and not systemic endothelial dysfunction. However, the probability whether impaired endothelial function in the posterior cerebral circulation, and intact endothelial function elsewhere is associated with migraine is not known. This is a post hoc study based on two of our previous published studies that evaluated cerebral and systemic endothelial function in 40 migraine patients (20 with (MwA) and 20 without aura (MwoA)) without comorbidities, and 20 healthy subjects. Cerebrovascular reactivity (CVR) to l -arginine in the middle (MCA) and posterior (PCA) cerebral artery as well as flow mediated vasodilatation (FMD) were used for this purpose. The logistic regression analysis was used to evaluate the association between CVR to l -arginine, FMD and migraine. We found a significant association between CVR to l -arginine in the PCA and migraine (OR: 0.38; CI 95%: 0.19–0.79; p = 0.01), but not between CVR to l -arginine in the MCA and migraine (OR: 0.74; CI 95%: 0.34–1.59; p = 0.44). Similar results were obtained in MwA and MwoA. We did not find any significant association between FMD and migraine (OR: 0.99; CI 95%: 0.83–1.19; p = 0.96). The same conclusion was reached in both migraine groups (MwA OR: 1.0; CI 95%: 0.83–1.19; p = 0.99, MwoA OR: 0.99; CI 95%: 0.81–1.21; p = 0.99). We could conclude that impaired endothelial function in the posterior cerebral circulation is associated with migraine, both MwA and MwoA, while intact endothelial function in the anterior cerebral and systemic circulation is not associated only with migraine.

Computed tomography angiography in patients with tuberculous meningitis

Strokes in tuberculous meningitis are important determinant of prognosis. Strokes are caused by tuberculosis-related vasculopathy. In this study, we aimed to demonstrate the value of computed tomography angiography. We also assessed value of angiographic findings in determining the prognosis. We included consecutive patients of tuberculous meningitis and prospectively followed them for 6 months. Computed tomography angiography was performed at inclusion. Follow-up angiography, after 6 months, was done in the patients, who had given consent. Angiographic findings were evaluated by experienced neuroradiologists. Initial computed tomography angiography revealed arterial narrowing or occlusion in 33 patients. In 30 patients the anterior cerebral circulation and in 9 patients posterior cerebral circulation was involved. Six (18.2%) patients had lesions in both the territories. The most frequently involved arteries were supraclinoid portion of the internal carotid artery, and proximal portions of the anterior cerebral and middle cerebral arteries. On univariate analysis, predictors of angiographic abnormalities were impaired vision (p=0.019), hemiparesis (p=0.002), hydrocephalous (p<0.001), basal exudates (p<0.001), meningeal enhancement (p=0.026) and infarcts (p<0.001). On multivariate analysis basal exudates was a significant predictor. Angiographic abnormalities were associated with insignificantly poorer prognosis. On follow-up angiograms, 3 patients showed resolution in vascular abnormalities. Two patients had developed new angiographic abnormalities. Arterial narrowing and occlusion is seen in majority of patients with tuberculous meningitis. Angiographic abnormalities may be associated with poor prognosis.

Endovascular treatment of tandem occlusions of the anterior cerebral circulation with solitaire FR thrombectomy system. Initial experience

PurposeThe optimal treatment in the acute phase of cervical internal carotid occlusion associated with intracranial obstruction is a matter of debate. In this study, we report our experience using the Solitaire FR revascularization device and synchronous intravenous fibrinolysis. The distal occlusion was treated with Solitaire FR before the proximal one in all cases, a technique not reported so far in the literature. MethodsWe examined all cases of tandem occlusion treated in our institution between November 2009 and November 2010. The proximal occlusion was treated using manual thromboaspiration in order to achieve intracranial recanalization as rapid as possible. When necessary, stenting was performed after the reconstitution of the intracranial vessel. Morphological and clinical results were recorded in the immediate post-operative phase and at the three-month follow-up. Clinical success was defined as a mRS at 3 months ≤2. ResultsFour male and six female patients were treated (mean age 66 years). The cervical carotid was recanalized in all cases and the intracranial vessel (TICI≥2b) in eight. Adverse events were recorded in four patients of which three were asymptomatic. These included two cases of subarachnoid hemorrhage, one case of traumatic dissection, and one case of fatal intra-cerebral hemorrhage seven days following the procedure. At the three-month follow-up a mRS≤2 was observed in four patients. ConclusionsThe described approach for the treatment of tandem occlusions is promising with regard to both morphological and clinical assessments and thus may be considered a valid tool in acute stroke.

Spinal cord infarction associated with subarachnoid hemorrhage

Paraplegia is a rare complication of subarachnoid hemorrhage (SAH) [1]. Acute paraparesis is proposed to be due to distortion of pyramidal tracts from hydrocephalus. The delayed occurrence is thought to be related to mass effect from interhemispheric clot or parasagittal ischemic strokes from vasospasm in the anterior cerebral circulation [1]. Spinal imaging in these reports has largely been reported negative. We report the delayed development of flaccid paraplegia from spinal cord stroke in a patient of subarachnoid hemorrhage caused by a ruptured anterior communicating artery aneurysm. This stroke was adjacent to a large collection of blood in the lumbo-sacral subarachnoid space. We discuss the various explanations of these findings including the novel possibility of vasospasm in spinal circulation.

Abstract 2219: Trevo System: Single Center Experience With A Novel Mechanical Thrombectomy Device

Background and Purpose: Recent reports have indicated that mechanical thrombectomy may have potential as a treatment for acute ischemic stroke. This study aims to describe the safety and effectiveness of Trevo RetrieverTM (Concentric Medical Inc, Mountain View, California) using StentrieverTM technology, in revascularization of patients with acute ischemic stroke. Methods: Prospective study evaluating the clinical, radiological and functional outcome of 13 patients with an angiographically verified occlusion of the anterior cerebral circulation. All patients underwent thrombectomy with TR as monotherapy or in combination with intra-arterial thrombolysis, within the first 8 hours from symptoms onset. Successful revascularization was defined as thrombolysis in cerebral ischemia grade 2a to 3. Good outcome was defined as modified Rankin Scale score ≤ 2. Results: Median baseline NIHSS score was 19 (16-22). The occlusion site was MCA in 8 patients and ICA in 5 patients. Five patients received IV tPA before endovascular procedure. Revascularization was achieved in 10 of 13 patients (77%). The median number of passes for maximal recanalization was 2 (1-3) and the mean time from groin puncture to recanalization was 95±31 minutes. No significant intra-procedural complications occurred. Four patients (30%) died during the 90-day follow-up period and 4 patients (30%) achieved functional independence at 3 months. Conclusions: Early clinical experience suggests that the TR can allow safe and effective revascularization in certain subjects with acute ischemic stroke.

Chronic meningitis and central nervous system vasculopathy related to Epstein Barr virus

Chronic active Epstein Barr virus (EBV) infection causes a wide spectrum of manifestation, due to meningeal, parenchymal and vascular involvement. An 11-year-old boy presented with chronic headache, fever and seizures of 18 months duration. His magnetic resonance imaging Brain showed fusiform aneurysmal dilatations of arteries of both the anterior and posterior cerebral circulation. Cerebrospinal fluid (CSF) showed persistent lymphocytic pleocytosis, raised proteins and low sugar with positive polymerase chain reaction for EBV. He later developed pancytopenia due to bone marrow aplasia, with secondary infection and expired. From clinical, imaging and CSF findings, he had chronic lymphocytic meningitis with vasculopathy, which was isolated to the central nervous system. He later had marrow aplasia probably due to X-linked lymphoproliferative disorder related to EBV infection. Vasculopathy, especially diffuse fusiform aneurysmal dilatation associated with chronic EBV infection, is rare, but has been described, similar to our case report.

Trevo System: Single‐Center Experience with a Novel Mechanical Thrombectomy Device

Recent reports have indicated that mechanical thrombectomy may have the potential to treat acute ischemic stroke. This study aims to describe the safety and effectiveness of Trevo Retriever, using Stentriever technology, in revascularization of patients with acute ischemic stroke. Prospective study evaluating the clinical, radiological, and functional outcome of 13 patients with an angiographically verified occlusion of the anterior cerebral circulation. All patients underwent thrombectomy with TR as monotherapy or in combination with intra-arterial thrombolysis, within the first 8 hours from the onset of symptoms. Successful revascularization was defined as thrombolysis in cerebral ischemia grade 2a to 3. Good outcome was defined as modified Rankin Scale score ≤ 2. Median baseline National Institutes of Health Stroke Scale score was 19(16-22). The occlusion site was middle cerebral artery in 8 patients and internal carotid artery in 5 patients. Revascularization was achieved in 10 of 13 patients (77%). The mean time from groin puncture to recanalization was 95 ± 31 minutes. No significant intra-procedural complications occurred. Four patients (30%) died during the 90-day follow-up period and 4 patients (30%) achieved functional independence. Early clinical experience suggests that the TR can allow safe and effective revascularization in certain subjects with acute ischemic stroke.

Utility of the Assessment of Echogenicity in the Identification of Symptomatic Carotid Artery Atheroma Plaques in Ischemic Stroke Patients

Background and Purpose: Echogenicity of atheroma carotid plaques is related to a higher risk of stroke. Clinical and subjective ultrasound criteria are used to identify symptomatic plaques, but the standardized grayscale median (GSM) value may be an objective tool for this diagnosis. Our aim was to analyze the utility of assessing the echogenicity of atheroma carotid plaques in the identification of symptomatic plaques. Methods: Observational prospective study with inclusion of acute noncardioembolic anterior cerebral circulation ischemic stroke patients. Only patients with bilateral atheroma plaques were included. Echogenicity of plaques was measured by a digital and standardized grayscale system in carotid ultrasound B-mode (longitudinal projection) conducted within the first week after admission. Results: Sixty-six patients were included and 132 plaques were examined. Symptomatic atheroma plaques were less echogenic than asymptomatic ones (GSM 20.0 vs. 29.0; p = 0.002). A ROC curve analysis showed the predictive value of GSM with an AUC of 0.707 (95% CI 0.592–0.823; p = 0.002) and pointed to a value of 24.4 as the optimal cut-off level to identify a plaque as symptomatic (74% sensitivity; 67% specificity). This GSM cut-off point remained significantly associated with a high probability of symptomatic plaque even after the inclusion of the degree of carotid stenosis (either >70% or >50%) in the multivariate logistic regression models. Conclusions: The assessment of echogenicity of atheroma carotid plaques by the GSM value combined with clinical characteristics and stenosis degree may be useful in the identification of symptomatic plaques.

Associations between cerebral and systemic endothelial function in migraine patients: a post-hoc study

BackgroundThere is a growing interest in the role of the endothelium in migraine. Recently, our group showed differences in endothelial function between the anterior and posterior cerebral circulation in healthy subjects, reduced vasodilatatory capacity of the posterior cerebral circulation and unimpaired systemic endothelial function in migraine patients without comorbidities. However, the relationship between cerebral and systemic endothelial function and the anterior and posterior cerebral endothelial function in migraine patients is still not clear.MethodsWe compared cerebral and systemic endothelial function through post-hoc linear regression analysis of cerebrovascular reactivity (CVR) to L-arginine between the middle cerebral artery (MCA) and flow-mediated vasodilatation (FMD) of the right brachial artery and the posterior cerebral artery (PCA) and FMD in migraine patients without comorbidities and in healthy subjects. The anterior and posterior cerebral endothelial function was also compared using post-hoc linear regression analysis between CVR to L-arginine in the MCA and the PCA.ResultsNo significant correlation was found between CVR to L-arginine in the MCA and FMD and in the PCA and FMD in migraine patients with aura (p = 0.880 vs. p = 0.682), without aura (p = 0.153 vs. p = 0.179) and in healthy subjects (p = 0.869 vs. p = 0.662). On the other hand, we found a significant correlation between CVR to L-arginine in the MCA and PCA in migraine patients with aura (p = 0.004), without aura (p = 0.001) and in healthy subjects (p = 0.002). Detailed analysis of the linear regression between all migraine patients and healthy subjects did not show any difference in the regression coefficient (slope) (p = 0.382). However, a significant difference in curve elevation (intercept) was found (p = 0.002).ConclusionsOur study suggests that the endothelial function in the cerebral and systemic circulation might be different in migraine patients without comorbidities, while that of the anterior and posterior cerebral circulation might be coupled. These results could improve understanding of endothelial function in migraine patients without comorbidities.

An aberrant cerebellar artery originating from the internal carotid artery

The aberrant origin of the cerebellar arteries from anterior cerebral circulation is a quite rare vascular variation. Herein, we report a 52-year-old white female with angiographically occult subarachnoid hemorrhage. Left superior and anterior inferior cerebellar arteries were not detected. An aberrant cerebellar artery was noted to arise from the left cavernous internal carotid artery and terminated in the distribution of the ipsilateral superior and anterior inferior cerebellar arteries. This variant artery might likely have resulted from an abnormal regression of fetal anterior-to-posterior circulation connections, and may represent a fetal-type cerebellar artery. A review of the anatomy and clinical significance of the variant is presented.

Ischaemic stroke among young people aged 15 to 50 years in Adelaide, South Australia

To report risk factors, aetiology and neuroimaging features among a large series of young Australian patients who were admitted to hospital for a first-ever occurrence of ischaemic stroke; to analyse the effect of age, sex and ethnicity on the presence of risk factors; and to compare Australian and overseas data. Retrospective evaluation of data for all patients aged from 15 to 50 years who were admitted to a public hospital in Adelaide, South Australia, from January 2006 to June 2010 with a primary diagnosis of ischaemic stroke. Among 326 patients (184 males), the most frequent stroke risk factors overall were dyslipidaemia (187), smoking (161), hypertension (105) and obesity (92). Fifty-one patients used illicit drugs, mostly comprising marijuana and amphetamines. The most frequent stroke aetiologies overall were cardioembolism (85), arterial dissection (49), and small-vessel occlusion (31). Cardioembolism was highly prevalent among our study population compared with patients in other countries. Neuroimaging showed that more patients in our study had strokes that involved both vascular territories concurrently (9%) compared with patients in other countries. Risk factors, aetiology and features of ischaemic stroke among young people in Adelaide differ significantly from published data for young patients around the world. Patients in Adelaide are more likely to be obese, to be misusing marijuana and amphetamines, to suffer a cardioembolic event and to have a stroke that concurrently affects both the anterior and posterior cerebral circulation.

Caudate body (CB) sign: New early CT sign of hyperacute anterior cerebral circulation infarction

This case series describes the caudate body (CB) sign noted in computed tomography (CT) scans of patients who presented to the Emergency Department (ED) clinically manifesting symptoms suggestive of anterior cerebral circulation infarction. This sign has the advantage of early appearance, side-to-side comparison, and high conspicuity. Two of the presented cases demonstrate the CB sign in the absence of other established signs typically seen with early cerebral infarction. Five additional cases demonstrate this sign in conjunction with previously described criteria. The CB sign may allow earlier detection of hyperacute infarction leading to more rapid initiation of thrombolytics to minimize ischemic injury.

The distribution of blood flow in the carotid and vertebral arteries during dynamic exercise in humans

The mechanism underlying the plateau or relative decrease in cerebral blood flow (CBF) during maximal incremental dynamic exercise remains unclear. We hypothesized that cerebral perfusion is limited during high-intensity dynamic exercise due to a redistribution of carotid artery blood flow. To identify the distribution of blood flow among the arteries supplying the head and brain, we evaluated common carotid artery (CCA), internal carotid artery (ICA), external carotid artery (ECA) and vertebral artery (VA) blood flow during dynamic exercise using Doppler ultrasound. Ten subjects performed graded cycling exercise in a semi-supine position at 40, 60 and 80% of peak oxygen uptake (VO2 peak) for 5 min at each workload. The ICA blood flow increased by 23.0 ± 4.6% (mean ± SE) from rest to exercise at 60% (VO2 peak). However, at 80% (VO2 peak), ICA blood flow returned towards near resting levels (9.6 ± 4.7% vs. rest). In contrast, ECA, CCA and VA blood flow increased proportionally with workload. The change in ICA blood flow during graded exercise was correlated with end-tidal partial pressure of CO2 (r = 0.72). The change in ICA blood flow from 60% (VO2 peak) to 80% (VO2 peak) was negatively correlated with the change in ECA blood flow (r = −0.77). Moreover, there was a significant correlation between forehead cutaneous vascular conductance and ECA blood flow during exercise (r = 0.79). These results suggest that during high-intensity dynamic exercise the plateau or decrease in ICA blood flow is partly due to a large increase in ECA blood flow, which is selectively increased to prioritize thermoregulation.