Cerebrovascular Reactivity Measured with ASL Perfusion MRI, Ivy Sign, and Regional Tissue Vascularization in Moyamoya.

BACKGROUND: Arterial spin labeling (ASL) perfusion magnetic resonance imaging (MRI) may be used to determine brain regions at risk for ischemia in patients with moyamoya vasculopathy and to identify patients who may benefit from surgical revascularization. We aimed to investigate whether 1) the severity of moyamoya is related to the presence of leptomeningeal collaterals and cerebrovascular reactivity (CVR), 2) the presence of collaterals and ivy sign reflects disturbed CVR, and 3) arterial transit artefacts (ATAs) and ivy sign reflect the presence of collaterals. METHODS: We determined severity of moyamoya on digital subtraction angiography (DSA) according to the modified Suzuki classification in 20 brain regions and scored regional tissue revascularization using a 4-point scale. Regional CVR and ATAs were assessed on ASL perfusion MRI, ivy sign on fluid attenuation inversion recovery MRI. RESULTS: In 11 patients (median age 36 years; 91% female), we studied 203 regions. ATAs were associated with the presence of collaterals on DSA (P < 0.01). Of all regions with clearly visible collateral vessels on DSA, however, only 24% had ATAs. Ivy sign was not related to the presence or absence of collaterals nor to CVR. In 10% of regions with good vascularization on DSA, CVR was poor or showed steal. CONCLUSIONS: ATAs were associated with the presence of collaterals on DSA. Although DSA vascularization scores correlated with CVR, 10% of regions with good vascularization on DSA had absent CVR or steal on ASL-MRI. DSA and ivy sign did not provide adequate information on the hemodynamic status of brain tissue in patients with moyamoya vasculopathy.

Arterial spin labeling perfusion MRI in children and young adults with previous ischemic stroke and unilateral intracranial arteriopathy.

BACKGROUND: Little is known about cerebral blood flow (CBF) in young patients with ischemic stroke caused by an intracranial arteriopathy. Arterial spin labeling (ASL) perfusion is a noninvasive technique for measuring CBF. We aimed to investigate whether, in young patients with unilateral intracranial arteriopathy and previous ischemic stroke, CBF is compromised in noninfarcted brain areas of the symptomatic hemisphere and whether this is related to the severity of the arteriopathy. METHODS: Patients aged 5-50 years, with previous middle cerebral artery (MCA) territory infarction and a unilateral intracranial arteriopathy, underwent magnetic resonance imaging (MRI), MR angiography and pseudocontinuous ASL perfusion MRI. We assessed the severity of stenosis of arteries that fed the symptomatic MCA territory, quantified CBF in the noninfarcted cortex of both MCA territories and generated CBF maps for visual CBF interpretation. RESULTS: A total of 17 patients were included (median age 29 years, range 5-49, 29% male). We found a similar median quantified CBF in the symptomatic and asymptomatic MCA territories (86 ml·100 g(-1)·min(-1)). CBF maps showed hypoperfusion in the symptomatic MCA territory in 59% of patients compared to 18% based on quantified CBF. Patients with a severe arteriopathy more often showed hypoperfusion on CBF maps than patients with a mild arteriopathy. In 53% of patients, small foci of increased signal intensity were visible on CBF maps around an area of hypoperfusion, indicating vascular artifacts. In these patients, we found large intraindividual variation in the quantified CBF in the symptomatic hemisphere. In 47% of patients, the visual interpretation of perfusion did not correspond with the quantified CBF. CONCLUSIONS: This study shows that more than half of young patients with previous ischemic stroke in the MCA territory and a unilateral intracranial arteriopathy have hypoperfusion in the noninfarcted cortex of the symptomatic hemisphere when CBF is visually assessed using a CBF map, in particular in patients with a severe arteriopathy. In the same patients, quantification of CBF shows hypoperfusion in the symptomatic hemisphere in only 18%. This discrepancy is caused by labeled blood within the arteries that has not yet reached the tissue at the time of imaging. Visual assessment can show hypoperfusion, while the quantified CBF in a similar region appears higher when the intravascular labeled blood is included in the region of interest. Further research should focus on elucidating whether cerebral perfusion deficits in young stroke patients with intracranial arteriopathy might help to identify patients who are at risk of poor outcome or stroke recurrence.

Unilateral movement disorder as a presenting sign of paediatric post-varicella angiopathy.

Diagnosing ischaemic stroke in children is often difficult. Post-varicella angiopathy (PVA) is a well-recognised and frequent cause of childhood ischaemic stroke, particularly affecting the basal ganglia. When a previously healthy child presents with unilateral abnormal involuntary movements, cerebral infarction should be included in the differential diagnosis and PVA should be considered, even when there is no recent history of rash and cerebrospinal fluid is normal. Medical history and intracranial vascular imaging are important for early diagnosis and treatment.

The course of unilateral intracranial arteriopathy in young adults with arterial ischemic stroke.

BACKGROUND AND PURPOSE: Unilateral intracranial focal nonprogressive arteriopathy is often found in children with arterial ischemic stroke. We aimed to investigate the course of unilateral intracranial arteriopathy in young adults. METHODS: We searched the Utrecht Stroke Database for patients between 16 and 50 years of age diagnosed with anterior circulation arterial ischemic stroke and a nonatherosclerotic, unilateral intracranial large-artery arteriopathy between 1991 and 2005. We assessed clinical features, potential causes, risk factors, extent of infarction and arteriopathy at presentation, long-term angiographic course, and clinical outcome. RESULTS: Of 356 patients with anterior circulation arterial ischemic stroke, 17 (5%) had a documented unilateral intracranial arteriopathy, of whom 14 could be included for follow-up investigations (median age, 34 years; range, 27-49 years). Median duration of follow-up was 8.8 years (range, 1.7-12.8 years). In 11 patients, onset of symptoms was not abrupt. The arteriopathy normalized completely in 5 and improved in 3 patients; in none of the patients did the arteriopathy worsen. Two of 14 patients had recurrent symptoms. Ten patients (71%) had a good outcome (modified Rankin Scale score≤2). CONCLUSIONS: In young adults, arterial ischemic stroke is rarely caused by a unilateral intracranial arteriopathy. Similar to children, onset of symptoms in young adults is often not abrupt and the arteriopathy may improve over time. Late recurrences were rare. Possibly, a monophasic inflammatory process, as has been suggested for childhood intracranial focal nonprogressive arteriopathies, also occurs in young adults.

Long-term reendothelialization of excimer laser-assisted nonocclusive anastomoses compared with conventionally sutured anastomoses in pigs.

OBJECT: In contrast to conventional anastomosis methods, the excimer laser-assisted nonocclusive anastomosis (ELANA) technique involves a platinum ring and intima-adventitia apposition with a rim of medial and adventitial layers exposed to the bloodstream. The authors assessed the reendothelialization of porcine carotid arteries through ELANA compared with conventional anastomosis by using scanning electron microscopy. METHODS: In 28 pigs a bypass with one ELANA and one conventional anastomosis was made on the left common carotid artery. All patent anastomoses were evaluated intraoperatively with the aid of an ultrasonographic flowmeter and postoperatively by using scanning electron microscopy at 2 weeks, 2 months, 3 months, and 6 months thereafter. Twenty-four of 28 bypasses (48 of 56 end-to-side anastomoses) were fully patent at the time of evaluation. On scanning electron microscopic evaluation of the bypasses, all 48 patent anastomoses showed complete reendothelialization, including all 24 ELANAs in which the endothelium covered the rim and the laser-ablated edge completely. No endothelial difference was observed between conventional anastomoses and ELANAs, aside from the obvious anatomical differences like the platinum ring, which had been completely covered with endothelium. At 6 months postsurgery, remodeling of the ELANA was observed, leaving the ring covered with a layer of endothelium as the most narrow part of the anastomosis. CONCLUSIONS: In long-term experiments, ELANA allows reendothelialization comparable to that achieved with conventional anastomosis. Considering its nonocclusive and high-flow characteristics, the ELANA technique is preferable in cerebral revascularization procedures.