Comparison of Clinical Characteristics and Functional Outcomes of Ischemic Stroke in Different Vascular Territories

BACKGROUND AND PURPOSE

We aim to compare demographics and functional outcomes of patients with stroke in a variety of vascular territories who underwent inpatient rehabilitation. Such comparative data are important in functional prognostication, rehabilitation, and healthcare planning, but literature is scarce and isolated.

METHODS

Using data collected prospectively over a 9-year period, we studied 2213 individuals who sustained first-ever ischemic strokes and were admitted to an inpatient stroke rehabilitation program. Strokes were divided into anterior cerebral artery, middle cerebral artery (MCA), posterior cerebral artery, brain stem, cerebellar, small-vessel strokes, and strokes occurring in more than one vascular territory. The main functional outcome measure was the Functional Independence Measure (FIM). Repeated-measures analysis of covariance with post hoc analyses was used to compare functional outcomes of the stroke groups.

RESULTS

The most common stroke groups were MCA stroke (50.8%) and small-vessel stroke (12.8%). After adjustments for age, gender, risk factors, and admission year, the stroke groups can be arranged from most to least severe disability on admission: strokes in more than one vascular territory, MCA, anterior cerebral artery, posterior cerebral artery, brain stem, cerebellar, and small-vessel strokes. The sequence was similar on discharge, except cerebellar strokes had the least disability rather than small-vessel strokes. Hemispheric (more than one vascular territory, MCA, anterior cerebral artery, posterior cerebral artery) strokes collectively have significantly lower admission and discharge total and cognitive FIM scores compared with the other stroke groups. MCA stroke had the lowest FIM efficiency and cerebellar stroke the highest. Regardless, patients with stroke made significant (P<0.001) and approximately equal (P=0.535) functional gains in all groups. Higher admission motor and cognitive FIM scores, longer rehabilitation stay, younger patients, lower number of medical complications, and a year of admission after 2000 were associated with higher discharge total FIM scores on multiple regression analysis.

CONCLUSIONS

Patients with stroke made significant functional gains and should be offered rehabilitation regardless of stroke vascular territory. The initial functional status at admission, rather than the stroke subgroup, better predicts discharge functional outcomes postrehabilitation.

Novel magnetic resonance angiography stage grading for moyamoya disease

BACKGROUND

Magnetic resonance angiography (MRA) has been acknowledged as a noninvasive diagnostic modality for moyamoya disease. However, in terms of staging of moyamoya disease, conventional angiography is still the gold standard. Therefore, the purpose of this study was to establish MRA grades for moyamoya disease as an alternative to conventional angiography.

METHODS

Twenty-two patients (44 sides) with moyamoya disease diagnosed by conventional angiography were evaluated by MRA during the past 5 years. MRA scores were assigned based on the severity of occlusive changes of the internal carotid artery, the horizontal portion of the middle cerebral artery, the anterior and the posterior cerebral arteries and the signals of the distal branches of these arteries. Total points ranged from 0 (normal) to 10 (most severe).

RESULTS

MRA scores (0-10) were significantly consistent with the conventional angiographic staging. Four grades based on this novel MRA scores correlated well with Suzuki's stages, with high sensitivity and specificity.

CONCLUSIONS

These novel MRA grades can be a reliable alternative to conventional staging. By employing these novel MRA grades, the use of conventional angiography can be avoided for the purpose of evaluation of the stages of moyamoya disease.

Comparison of three rat models of cerebral vasospasm

A substantial number of rat models have been used to research subarachnoid hemorrhage-induced cerebral vasospasm; however, controversy exists regarding which method of selection is appropriate for this species. This study was designed to provide extensive information about the three most popular subarachnoid hemorrhage rat models: the endovascular puncture model, the single-hemorrhage model, and the double-hemorrhage model. In this study, the basilar artery and posterior communicating artery were chosen for histopathological examination and morphometric analysis. Both the endovascular puncture model and single-hemorrhage model developed significant degrees of vasospasm, which were less severe when compared with the double-hemorrhage model. The endovascular puncture model and double-hemorrhage model both developed more vasospasms in the posterior communicating artery than in the basilar artery. The endovascular puncture model has a markedly high mortality rate and high variability in bleeding volume. Overall, the present study showed that the double-hemorrhage model in rats is a more suitable tool with which to investigate mechanism and therapeutic approaches because it accurately correlates with the time courses for vasospasm in humans.

Posterior circulation stroke in childhood: risk factors and recurrence

OBJECTIVE

To ascertain whether posterior circulation stroke in children has distinctive clinical or radiologic features.

METHODS

Patients were identified retrospectively from two pediatric neurology centers. Clinical details were ascertained by chart review, and radiologic data were reviewed by three neuroradiologists.

RESULTS

Twenty-two cases were identified (17 boys). Twenty children had evidence of vertebrobasilar arterial abnormalities, which were multifocal in 12. The etiology of these was vertebral artery dissection in 10 cases and unclear in the remaining 10. Cardiac abnormalities were rare (n = 4). Other risk factors for stroke in childhood were hypertension (n = 9), the thermolabile methylene tetrahydrofolate reductase gene mutation (n = 4), and the factor V Leiden mutation (n = 2). Two children had subluxation of the upper cervical spine at the extreme of normal limits. In follow-up for 6 months to 11 years (median 4 years), five patients had further strokes and seven had TIA. Overall, 12 patients had no residual neurologic deficits.

CONCLUSIONS

The male preponderance, frequency of arterial dissection, rarity of cardiac embolism, and >20% recurrence were notable. Cerebral angiography is usually indicated if a definitive diagnosis is not made on MRI. Additional investigations should include echocardiography and cervical spine radiography in flexion and extension.

Pure midbrain infarction: Clinical, radiologic, and pathophysiologic findings

OBJECTIVE

To describe the clinical features, MRI findings, and the pathogenesis of the pure midbrain infarction.

METHODS

Forty patients with infarcts limited to the midbrain were studied. MRI and angiography (mostly MR angiography) were performed in all patients.

RESULTS

Clinical manifestations included gait ataxia in 27 (68%) patients, dysarthria in 22 (55%), limb ataxia in 20 (50%), sensory symptoms in 17 (43%), third nerve palsy in 14 (35%), definitive limb weakness (< or =IV/V) in nine (23%), and internuclear ophthalmoplegia in five (13%). According to MRI findings, the lesions were categorized into four groups. The anteromedial group (n = 18) was characterized by oculomotor disturbances (89%), ataxia (89%, bilateral in 17%), and sensory changes (39%) usually restricted to the perioral and hand areas. Lesions restricted to the subcortical area (n = 10) were usually related to small vessel disease (SVD) (78%), whereas those involving the medial surface (n = 8) were caused by large vessel disease (LVD) (78%). The anterolateral group (n = 11) was characterized by ataxia (70%) and definitive hemiparesis (30%) usually caused by LVD (82%). The combined group (n = 6) had frequent oculomotor disturbances (83%), definitive hemiparesis (67%), and ataxia (50%) and was usually associated with LVD (67%). The lateral group (n = 2) was characterized by prominent sensory symptoms. The prognosis was generally good except for one patient with a bilateral lesion.

CONCLUSION

Clinical-radiologic correlation study yields four distinct subgroups: anteromedial, anterolateral, combined, and lateral. Large vessel disease and small vessel disease are usual pathogenic mechanisms, whereas cardiogenic embolism is rare.

Successful endovascular therapy for acute basilar thrombosis in an adolescent

Pediatric stroke is an underrecognized, potentially treatable cause of childhood neurologic disease. Acute basilar artery thrombosis is a devastating disease rarely encountered in children. Acute interventions with both chemical and mechanical thrombolysis techniques can improve outcomes in adults with arterial thrombosis of the posterior cerebral circulation. We report a case of intervention with both intra-arterial alteplase (tissue plasminogen activator) and cerebral balloon angioplasty to treat a prolonged basilar artery occlusion secondary to idiopathic thrombosis in an adolescent. Despite the patient being clinically locked-in and intervention being delayed at least 20 hours from symptom onset, he obtained complete neurologic recovery. Issues of pediatric stroke, late therapeutic intervention, chemical thrombolysis, and cerebral angioplasty are discussed. This case highlights the underrecognition and subsequent delay in diagnosis of pediatric stroke and how acute intervention may cure otherwise catastrophic strokes in children.

Visual neglect after right posterior cerebral artery infarction

OBJECTIVES

To investigate the characteristics and neuroanatomical correlates of visual neglect after right-sided posterior cerebral artery (PCA) infarction.

METHODS

15 patients with acute PCA strokes were screened for the presence of neglect on a comprehensive battery of cognitive tests. Extra tests of visual perception were also carried out on six patients. To establish which areas were critically associated with neglect, the lesions of patients with and without neglect were compared.

RESULTS

Neglect of varying severity was documented in 8 patients. In addition, higher-order visual perception was impaired in 5 of the 6 patients. Neglect was critically associated with damage to an area of white matter in the occipital lobe corresponding to a white matter tract connecting the parahippocampal gyrus with the angular gyrus of the parietal lobe. Lesions of the thalamus or splenium of the corpus callosum did not appear necessary or sufficient to cause neglect, but may mediate its severity in these patients.

CONCLUSIONS

PCA stroke can result in visual neglect. Interruption of the white matter fibres connecting the parahippocampal gyrus to the angular gyrus may be important in determining whether a patient will manifest neglect.

MICROSURGICAL APPROACHES TO THE PERIMESENCEPHALIC CISTERNS AND RELATED SEGMENTS OF THE POSTERIOR CEREBRAL ARTERY: COMPARISON USING A NOVEL APPLICATION OF IMAGE GUIDANCE

OBJECTIVE

To describe the exposure obtained through six approaches to the perimesencephalic cisterns with an emphasis on exposure of the posterior cerebral artery and its branches.

METHODS

Dissections in 12 hemispheres exposed the crural, ambient, and quadrigeminal cisterns and related segments of the posterior cerebral artery. A Stealth Image Guidance workstation (Medtronic Surgical Navigation Technologies, Louisville, CO) was used to compare the approaches.

RESULTS

The transsylvian approach exposed the interpeduncular and crural cisterns. The subtemporal approach exposed the interpeduncular and crural cisterns as well as the lower half of the ambient cistern. Temporal lobe retraction and the position of the vein of Labbé limited exposure of the quadrigeminal cistern. Occipital transtentorial and infratentorial supracerebellar approaches exposed the quadrigeminal and lower two-thirds of the ambient cistern. Transchoroidal approaches exposed the posterior third of the crural cistern, the upper two-thirds of the ambient cistern, and the proximal quadrigeminal cistern. Transchoroidal approaches exposed the posterior portion of the P2 segment (P2p) in 9 of 10 hemispheres and were the only approaches that exposed the lateral posterior choroidal arteries and the plexal segment of the anterior choroidal artery. Occipital transtentorial and infratentorial supracerebellar approaches provided access to the P3 segment in all cases and exposed the P2p segment in 4 of 10 hemispheres. The subtemporal approach provided access to the cisternal and crural segments of the anterior choroidal and medial posterior choroidal arteries and exposed the P2p segment in 3 of 10 hemispheres.

CONCLUSION

Surgical approaches to lesions of the perimesencephalic cisterns must be tailored to the site of the pathological findings. The most challenging area to expose is the upper half of the ambient cistern, particularly the P2p segment of the posterior cerebral artery.

Alexithymic features in stroke: effects of laterality and gender

OBJECTIVE

Stroke patients suffer from a high rate of behavioral disorders, and the laterality of the lesion may affect the expression of emotional disturbances. This study tested the hypothesis that stroke patients with a lesion in the right hemisphere are at high risk of developing alexithymic features.

METHODS

Forty-eight patients were interviewed with the Structured Clinical Interview for DSM-IV (patient edition), the Mini-Mental State Examination, the State-Trait Anxiety Inventory (state form), the Beck Depression Inventory, and the Toronto Alexithymia Scale (20-item version). Alexithymic differences between stroke patients with a lesion in the right hemisphere and those with a lesion in the left hemisphere were computed by analysis of covariance, using scores on the Mini-Mental State Examination, Beck Depression Inventory (psychic subscore), and State-Trait Anxiety Inventory as covariates and the score on the Toronto Alexithymia Scale as the dependent variable. A multivariate analysis of covariance and a series of follow-up analyses of covariance with the same covariates were used to discriminate differences in subscores on the Toronto Alexithymia Scale. An exploratory analysis of covariance was also performed to determine the effect of gender on alexithymic features in both groups of stroke patients.

RESULTS

The 21 stroke patients with a lesion in the right hemisphere were more alexithymic than the 27 patients with a lesion in the left hemisphere. This evidence was strengthened by the categorical analysis: 48% of the patients with a right-hemisphere lesion had alexithymia, compared with 22% of patients with a left-hemisphere lesion. Univariate analyses of covariance showed significant differences between the two groups in difficulty identifying feelings and difficulty describing feelings, but not in externally oriented thinking. The last exploratory analysis of covariance suggested that gender may influence alexithymic features.

CONCLUSIONS

This study provides direct evidence that alexithymia, and more specifically difficulty identifying feelings and difficulty describing feelings, is more common in stroke patients with a right-hemisphere lesion than in those with a left-hemisphere lesion. It also provides preliminary evidence that gender may affect alexithymic expression.

Basilar artery to bilateral posterior cerebral artery 'Y stenting' for endovascular reconstruction of wide-necked basilar apex aneurysms: report of three cases

Endovascular reconstruction of basilar artery (BA) apex aneurysms has been augmented by adjunctive techniques such as balloon and stent assistance. We present three cases of a wide-necked BA apex aneurysm involving the bilateral P1 segments of both posterior cerebral arteries (PCAs) treated by placement of BA to PCA stents bilaterally in a 'Y' configuration to reconstruct the BA apex for effective coil embolization. Three patients (aged 70, 65 and 37 years) with wide-necked basilar artery aneurysms presented for endovascular treatment. All aneurysms had necks that involved the bilateral P1 segments. Each patient was deemed an appropriate candidate for endovascular reconstruction. Patients were pretreated with clopidogrel (75 mg) and aspirin (325 mg) each day for 3 days prior to the procedure. Following induction of general anesthesia, access to the right femoral artery was obtained by placement of a 6F sheath. Intravenous heparin was administered to achieve an activated coagulation time (ACT) of approximately 300 seconds. A 6F guide catheter was placed within the left vertebral artery (VA) in two patients, the right VA in a third. Utilizing over-the-wire (OTW) technique, a microcatheter was advanced into the left P2-P3 junction of the PCA. A 300-cm 0.014-inch microwire was passed through the microcatheter into the distal PCA and the microcatheter was removed. In each case, two neuroform stents were prepared (SMART Therapeutics Inc., San Leandro, CA) and advanced OTW into the PCA with the most acute angle relative to the BA. The initial stent placed was 20 mm in length and was deployed from the P1 segment into the BA. The microwire was pulled retrograde into the BA apex, then advanced though the stent struts and into the right PCA. A second stent, 15 mm in length, was advanced OTW through the struts of the previously placed stent. It was then deployed from the P1 into the BA where it overlapped the first stent, resulting in a stent-in-stent 'Y' configuration at the BA apex. A microcatheter was advanced OTW into the BA apex aneurysm and coil embolization proceeded in the usual fashion. Following the procedure, each patient was maintained in the neurosurgical intensive care unit (NICU). All remained neurologically intact. The two elderly patients were discharged to home the morning following the procedure. The third patient suffered an upper GI bleed and was treated an additional 3 days in hospital. Oral clopidogrel (75 mg by mouth) and aspirin (325 mg by mouth) were continued daily for 4 weeks. The 'Y' stent configuration for reconstruction of the BA apex is a safe effective technique in patients with wide-necked BA aneurysms.

Aging is associated with changes to the biomechanical properties of the posterior cerebral artery and parenchymal arterioles

Artery remodeling, described as a change in artery structure, may be responsible for the increased risk of cardiovascular disease with aging. Although the risk for stroke is known to increase with age, relatively young animals have been used in most stroke studies. Therefore, more information is needed on how aging alters the biomechanical properties of cerebral arteries. Posterior cerebral arteries (PCAs) and parenchymal arterioles (PAs) are important in controlling brain perfusion. We hypothesized that aged (22-24 mo old) C57bl/6 mice would have stiffer PCAs and PAs than young (3-5 mo old) mice. The biomechanical properties of the PCAs and PAs were assessed by pressure myography. Data are presented as means ± SE of young vs. old. In the PCA, older mice had increased outer (155.6 ± 3.2 vs. 169.9 ± 3.2 μm) and lumen (116.4 ± 3.6 vs. 137.1 ± 4.7 μm) diameters. Wall stress (375.6 ± 35.4 vs. 504.7 ± 60.0 dyn/cm(2)) and artery stiffness (β-coefficient: 5.2 ± 0.3 vs. 7.6 ± 0.9) were also increased. However, wall strain (0.8 ± 0.1 vs. 0.6 ± 0.1) was reduced with age. In the PAs from old mice, wall thickness (3.9 ± 0.3 vs. 5.1 ± 0.2 μm) and area (591.1 ± 95.4 vs. 852.8 ± 100 μm(2)) were increased while stress (758.1 ± 100.0 vs. 587.2 ± 35.1 dyn/cm(2)) was reduced. Aging also increased mean arterial and pulse pressures. We conclude that age-associated remodeling occurs in large cerebral arteries and arterioles and may increase the risk of cerebrovascular disease.

Peroxynitrite diminishes myogenic activity and is associated with decreased vascular smooth muscle F-actin in rat posterior cerebral arteries

BACKGROUND AND PURPOSE

This study investigated the effect of peroxynitrite (ONOO-) on pressure-induced myogenic activity and vascular smooth muscle (VSM) actin of isolated posterior cerebral arteries (PCAs).

METHODS

Histochemical staining of nitrotyrosine (NT) was used to demonstrate the presence of ONOO- in the cerebrovasculature after 1 hour of middle cerebral artery occlusion with 30 minutes of reperfusion. To determine the effect of ONOO- on pressure-induced myogenic activity, third-order PCAs from nonischemic animals were isolated and mounted in an arteriograph chamber. Diameter in response to changes in pressure was determined in the absence and presence of ONOO- (10(-8) to 10(-4) mol/L). Filamentous actin (F-actin) and globular actin (G-actin) were quantified using confocal microscopy in PCAs with and without exposure to ONOO-.

RESULTS

NT staining of vascular cells was greater in ischemic brain versus sham animals (56+/-3% versus 35+/-3%; P<0.01). Addition of low concentrations of ONOO- (< or =10(-6) mol/L) to isolated PCAs caused constriction from 129+/-16 microm to 115+/-15 microm (P<0.01), whereas concentrations >10(-6) mol/L caused dilation of spontaneous tone and loss of myogenic activity in the physiological range of 50 to 125 mm Hg, increasing diameter from 130+/-6 to 201+/-5 microm at 75 mm Hg (P<0.01). In addition, the diminished myogenic activity was associated with a 4.5-fold decrease in F-actin content of VSM and a 27% increase in G-actin content (P<0.01).

CONCLUSIONS

This study demonstrates that ONOO- affects the myogenic activity of cerebral arteries and causes F-actin depolymerization in VSM, a consequence that could promote vascular damage during reperfusion injury and further brain injury.

Comparison of susceptibility weighted imaging and TOF-angiography for the detection of Thrombi in acute stroke

BACKGROUND AND PURPOSE

Time-of-flight (TOF) angiography detects embolic occlusion of arteries in patients with acute ischemic stroke due to the absence of blood flow in the occluded vessel. In contrast, susceptibility weighted imaging (SWI) directly enables intravascular clot visualization due to hypointense susceptibility vessel signs (SVS) in the occluded vessel. The aim of this study was to compare the diagnostic accuracy of both methods to determine vessel occlusion in patients with acute stroke.

METHODS

94 patients were included who presented with clinical symptoms for acute stroke and displayed a delay on the time-to-peak perfusion map in the territory of the anterior (ACA), middle (M1, M1/M2, M2/M3) or posterior (PCA) cerebral artery. The frequency of SVS on SWI and vessel occlusion or stenosis on TOF-angiography was compared using the McNemar-Test.

RESULTS

87 of 94 patients displayed a clearly definable SVS on SWI. In 72 patients the SVS was associated with occlusion or stenosis on TOF-angiography. Fifteen patients exclusively displayed SVS on SWI (14 M2/M3, 1 M1), whereas no patient revealed exclusively occlusion or stenosis on TOF-angiography. Sensitivity for detection of embolic occlusion within major vessel segments (M1, M1/M2, ACA, and PCA) did not show any significant difference between both techniques (97% for SWI versus 96% for TOF-angiography) while the sensitivity for detection of embolic occlusion within M2/M3 was significantly different (84% for SWI versus 39% for TOF-angiography, p<0.00012).

CONCLUSIONS

SWI and TOF-angiography provide similar sensitivity for central thrombi while SWI is superior for the detection of peripheral thrombi in small arterial vessel segments.

Pure superficial posterior cerebral artery territory infarction in The Lausanne Stroke Registry

OBJECTIVE

To determine the patterns of clinical presentation, lesion topography, and etiology in patients with ischemic stroke limited to the superficial territory of the posterior cerebral artery (s-PCA).

METHODS

In the Lausanne Stroke Registry (LSR, 1983-1998), we determined the patterns of clinical presentation, lesion topography and mechanisms of stroke, among 117 patients with s-PCA infarction (s-PCAI) on brain imaging.

RESULTS

s-PCAIs accounted for 30.5 % of all PCA territory ischemic strokes. The presumed etiology was embolism in 64 (54.5 %) patients [cardiac in 51 (43.5 %) and arterial in 13 (11 %)], indeterminate in 38 (32 %), PCA atherothrombosis in 4 (3.4 %), migraine in 4 (3.4 %), other rare causes in 4 (3.4 %), and multiple potential sources of embolism in 3 (2.5 %). The clinical findings were hemianopsia in 78 (67 %), quadrantanopsia in 26 (22 %), and bilateral visual field defects in 8 (7 %). Motor, sensory, or sensorimotor deficits were detected in 14 (12 %), 8 (6.8 %), or 8 (6.8 %) patients, respectively. Neuropsychological dysfunction included memory impairment in 20 (17.5 %; with left [L], right [R], or bilateral [B] lesions in 15, 2, or 3 patients, respectively), dysphasia in 17 (14.5 %; L/B: 14/3), dyslexia with dysgraphia in 5 (4 %; L/B: 4/1), dyslexia without dysgraphia in 10 (8.5 %; L/B: 8/2), hallucinations in 12 (10 %; L/R/B: 5/5/2), visual neglect in 11 (9.5 %; L/R: 2/9), visual agnosia in 10 (8.5 %; L/B: 7/3), prosopagnosia in 7 (6 %; R/B: 4/3), and color dysnomia in 6 (5 %; L: 6).

CONCLUSIONS

s-PCAIs are uncommon, representing less than a third of all PCA infarctions. Although embolism is the main cause in 60 % of patients, identification of the emboli source is often not possible. In 1/3 of cases, the stroke mechanism cannot be determined. Neuropsychological deficits are frequent if systematically searched for.

Deafferentation-disconnection neglect induced by posterior cerebral artery infarction

OBJECTIVE

To investigate patients with posterior cerebral artery (PCA) infarctions to learn whether hemispatial neglect is more frequent and severe after right than left PCA infarction; whether visual field defects (VFDs) influence the presence or severity of hemispatial neglect; and the anatomic loci of lesions that are associated with hemispatial neglect.

METHODS

The authors recruited 45 patients with PCA infarction that involved only the occipital lobe or the occipital lobe plus other areas served by the PCA. All subjects received seven neglect tests within 2 months after onset.

RESULTS

Overall, the frequency of hemispatial neglect was 42.2%. The frequency did not significantly differ between the right (48.0%) and left (35.0%) PCA groups, but the severity of hemispatial neglect was significantly greater in the right group. VFD alone did not influence the frequency or severity of neglect after controlling other variables. Isolated occipital lesions were rarely associated with hemispatial neglect, and it was only the occipital plus splenial lesion that significantly influenced the frequency and severity of neglect.

CONCLUSIONS

This study suggests that after excluding such confounding factors as aphasia or hemiplegia, neglect frequency does not differ between the right and left posterior cerebral artery (PCA) groups, but the severity of neglect is greater after right PCA infarctions; even in the acute stage of PCA infarction; visual field defect from an isolated occipital lesion does not cause hemispatial neglect; and the injury to both the occipital lobe and the splenium of the corpus callosum is important for producing hemispatial neglect with PCA infarction.

The hyperdense posterior cerebral artery sign: a computed tomography marker of acute ischemia in the posterior cerebral artery territory

BACKGROUND AND PURPOSE

In the anterior circulation, the hyperdense middle cerebral artery (MCA) sign is a well-established marker for early ischemia. Similarly, the hyperdense basilar artery sign or the MCA "dot" sign may be a diagnostic clue for basilar artery or distal MCA branch thrombosis. The purpose of this study was to define the hyperdense posterior cerebral artery (PCA) sign and determine its incidence, diagnostic value, and reliability as a marker for ischemia in the territory of the PCA.

METHODS

Cranial computed tomographies (CCTs) of 48 patients with proven acute ischemia (<12 hours) in the PCA territory were compared by 3 independent and blinded readers to the CCTs of 86 age-matched patients without PCA infarction. Using follow-up imaging, the correlation of the hyperdense PCA (HPCA) with infarct size, thalamic infarction, and bleeding were investigated.

RESULTS

An HPCA was found in 35.4% of all patients with PCA infarction, typically within the ambient cistern, with a specificity of 95.4%. The thalamus was affected significantly more often (P=0.009) and the size of the infarct was significantly more often large than medium (P=0.018) or small (P<0.001) when an HPCA was present. Hemorrhagic transformation tended to occur more often when the HPCA was present.

CONCLUSIONS

An HPCA was detected in more than one third of all patients with PCA ischemia, suiting the incidence of the hyperdense MCA. Based on our results, this sign may not only be helpful in the early diagnosis of PCA infarction but might also act as a prognostic marker in acute PCA territory ischemic stroke.

Normal variants of the intracranial circulation demonstrated by MR angiography at 3T

Magnetic resonance angiography (MRA) at 3T offers increased signal to noise ratio with better background suppression, leading to exquisite depiction of the intracranial circulation. We present a pictorial review of the normal variations and anomalies of the intracranial circulation detected on MRA performed on a high field 3T clinical scanner using parallel imaging techniques. The salient imaging features of these anomalies and normal variations are discussed with relevance to clinical practice.

Spectrum of superficial posterior cerebral artery territory infarcts. Clinical and outcome correlates

Posterior cerebral artery (PCA) territory infarction is not uncommon. Published series were concentrated either on isolated deep PCA territory infarcts or on incomplete calcarine artery territory infarcts. Although, correlations between clinical symptoms, causes of stroke and outcome at 6-months in patients with superficial PCA territory stroke are less well known. We sought prospectively stroke causes, infarct topography, and clinical findings of 137 patients with superficial PCA territory infarcts with or without mesencephalic/thalamic involvement, representing 11% of patients with posterior circulation ischemic stroke in our Stroke Registry. We analyzed patients by subdividing into three subgroups; (1). cortical infarct (CI) group; (2). cortical and deep infarcts (CDI) (thalamic and/or mesencephalic involvement) group; (3). bilateral infarcts (BI) group. We studied the outcomes of patients at 6-month regarding clinical findings, risk factors and vascular mechanisms by means of comprehensive vascular and cardiac studies. Seventy-one patients (52%) had cortical (CI) PCA infarct, 52 patients (38%) had CDI, and 14 patients (10%) had bilateral PCA infarct (BI). In the CDI group, unilateral thalamus was involved in 38 patients (73%) and unilateral mesencephalic involvement was present in 27% of patients. The presumed causes of infarction were intrinsic PCA disease in 33 patients (26%), proximal large-artery disease (PLAD) in 33 (24%), cardioembolism in 23 (17%), co-existence of PLAD and cardioembolism in 7 (5%), vertebral or basilar artery dissection in 8 (6%), and coagulopathy in 2. The death rate was 7% in our series and stroke recurrence was 16% during 6-month follow-up period. Features of the stroke that was associated with significant increased risk of poor outcome included, consciousness disturbances at stroke onset (RR, 66.6; 95% CI, 8.6-515.5), mesencephalic and/or thalamic involvement (RR, 3.79; 95% CI, 1.49-9.65), PLAD (RR, 2.71; 95% CI, 1.09-6.73), and basilar artery disease (RR, 5.94; 95% CI, 1.73-20.47). The infarct mechanisms in three different types of superficial PCA territory stroke were quite similar, but cardioembolism was found more frequent in those with cortical PCA territory infarction. Although, the cause of stroke could not reliably dictate the infarct topography and clinical features. Visual field defect was the main clinical symptom in all groups, but sensorial, motor and neuropsychological deficits occurred mostly in those with CDI. Outcome is good in general, although patients having PLAD and basilar artery disease had more risk of stroke recurrence and poor outcome rather than those with intrinsic PCA disease.

Three-dimensional time-of-flight MR angiography for evaluation of intracranial aneurysms after endosaccular packing with Guglielmi detachable coils: comparison with 3D digital subtraction angiography

The sensitivities and specificities of three-dimensional time-of-flight MR angiography (3D-TOF MRA) and 3D digital subtraction angiography (3D-DSA) were compared for evaluation of cerebral aneurysms after endosaccular packing with Guglielmi detachable coils (GDCs). Thirty-three patients with 33 aneurysms were included in this prospective study. 3D-TOF MRA and 3D-DSA were performed in the same week on all patients. Maximal intensity projection (MIP) and 3D reconstructed MRA images were compared with 3D-DSA images. The diameters of residual/recurrent aneurysms detected on 3D-DSA were calculated on a workstation. In 3 (9%) of 33 aneurysms, 3D-TOF MRA did not provide reliable information due to significant susceptibility artifacts on MRA. The sensitivity and specificity rates of MRA were 72.7 and 90.9%, respectively, for the diagnosis of residual/recurrent aneurysm. The diameters of residual/recurrent aneurysms that could not be detected by MRA were significantly smaller than those of detected aneurysms (mean 1.1 vs mean 2.3 mm). In one aneurysm of the anterior communicating artery (ACoA), the relationship between the residual aneurysm and the ACoA was more evident on MRA than DSA images. MRA can detect the recurrent/residual lumen of aneurysms treated with GDCs of up to at least 1.8 mm in diameter. 3D-TOF MRA is useful for follow-up of intracranial aneurysms treated with GDCs, and could partly replace DSA.

Visual agnosia and posterior cerebral artery infarcts: an anatomical-clinical study

Background

To evaluate systematically the cognitive deficits following posterior cerebral artery (PCA) strokes, especially agnosic visual disorders, and to study anatomical-clinical correlations.

Methods and Findings

We investigated 31 patients at the chronic stage (mean duration of 29.1 months post infarct) with standardized cognitive tests. New experimental tests were used to assess visual impairments for words, faces, houses, and objects. Forty-one healthy subjects participated as controls. Brain lesions were normalized, combined, and related to occipitotemporal areas responsive to specific visual categories, including words (VWFA), faces (FFA and OFA), houses (PPA) and common objects (LOC). Lesions were located in the left hemisphere in 15 patients, in the right in 13, and bilaterally in 3. Visual field defects were found in 23 patients. Twenty patients had a visual disorder in at least one of the experimental tests (9 with faces, 10 with houses, 7 with phones, 3 with words). Six patients had a deficit just for a single category of stimulus. The regions of maximum overlap of brain lesions associated with a deficit for a given category of stimuli were contiguous to the peaks of the corresponding functional areas as identified in normal subjects. However, the strength of anatomical-clinical correlations was greater for words than for faces or houses, probably due to the stronger lateralization of the VWFA, as compared to the FFA or the PPA.

Conclusions

Agnosic visual disorders following PCA infarcts are more frequent than previously reported. Dedicated batteries of tests, such as those developed here, are required to identify such deficits, which may escape clinical notice. The spatial relationships of lesions and of regions activated in normal subjects predict the nature of the deficits, although individual variability and bilaterally represented systems may blur those correlations.

Changes in artistic style after minor posterior stroke

BACKGROUND

Two professional painters experienced significant changes in their art as the main consequence of minor stroke located in the left occipital lobe or thalamus.

METHODS

The features of this artistic conversion were analysed on the basis of extensive neurological, neuropsychological, and psychiatric evaluations.

RESULTS

Both painters, initially unaware of the artistic changes, exhibited mild signs of executive dysfunction, but no general cognitive decline. The first painter, who showed mild visual-perceptive difficulties (dyschromatopsia and scotoma in his right upper visual field after left occipital stroke), together with increased anxiety and difficulty in emotional control, switched to a more stylised and symbolic art. The second painter, who also presented features of emotionalism related to his left latero-thalamic stroke, switched from an impressionist style to a more joyous and geometric, but more simplistic, abstract art.

CONCLUSIONS

These findings show that mild cognitive and affective modifications due to focal posterior brain lesions can have significant repercussions on artistic expression.

Assessment of vasogenic edema in eclampsia using diffusion imaging

We qualitatively assessed the regional distribution of vasogenic edema in a case of postpartum eclampsia. Although diffusion-weighted imaging showed no abnormalities, bilateral high signal was seen on T2-weighted images and apparent diffusion coefficient (ADC) maps. ADC of 1.45 +/- 0.10 mm2/s x 10(-3) for the posterior cerebral artery (PCA) territory and 1.22 +/- 0.12 mm2/s x 10(-3) for the watershed areas were significantly higher than those in the territories of the anterior (0.85 +/- 0.07 mm2/s x 10(-3) and middle cerebral (0.79 +/- 0.06 mm2/s x 10(-3)) arteries (P < 0.05). The predilection of ADC changes within the PCA territory and in a previously undescribed watershed distribution supports the hypothesis that vasogenic edema in eclampsia is due to hypertension-induced failure of vascular autoregulation.