Intracranial Vasculopathies Research Articles

Qualitative Assessment and Reporting Quality of Intracranial Vessel Wall MR Imaging Studies: A Systematic Review.

Over the last quarter-century, the number of publications using vessel wall MR imaging has increased. Although many narrative reviews offer insight into technique and diagnostic applications, a systematic review of publication trends and reporting quality has not been conducted to identify unmet needs and future directions. We aimed to identify which intracranial vasculopathies need more data and to highlight areas of strengths and weaknesses in reporting. PubMed, EMBASE, and MEDLINE databases were searched up to September 2018 in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Two independent reviewers screened and extracted data from 128 articles. The Strengthening the Reporting of Observational Studies in Epidemiology guidelines were used to assess the reporting quality of analytic observational studies. There has been an exponentially increasing trend in the number of vessel wall MR imaging publications during the past 24 years (P < .0001). Intracranial atherosclerosis is the most commonly studied intracranial vasculopathy (49%), followed by dissections (13%), aneurysms (8%), and vasculitis (5%). Analytic observational study designs composed 48% of the studies. Transcontinental collaborations showed nonsignificantly higher reporting quality compared with work originating from single continents (P = .20). A limitation is the heterogeneity in study designs. Investigations on the diagnostic utility of vessel wall MR imaging in less commonly studied intracranial vasculopathies such as dissections, aneurysms, and vasculitis are warranted. More consistent adherence to the Strengthening the Reporting of Observational Studies in Epidemiology guidelines should improve transparency and maximize effective synthesis for clinical translation. Diverse collaborative teams are encouraged to advance the understanding of intracranial vasculopathies using vessel wall MR imaging.

Utility of intracranial high-resolution vessel wall magnetic resonance imaging in differentiating intracranial vasculopathic diseases causing ischemic stroke.

High-resolution vessel wall imaging (HRVWI) by MRI is a novel noninvasive imaging tool which provides direct information regarding vessel wall pathologies. The utility of HRVWI in differentiating various intracranial vasculopathies among ischemic stroke is still evolving. Consecutive ischemic stroke/TIA patients within 2weeks of symptom onset between January 2016 to December 2017, with symptomatic vessel stenosis of 50% or more/occlusion on baseline luminal imaging studies were recruited into the study. Stroke subtypes were classified as per TOAST classification initially on the basis of luminal imaging findings alone and subsequently after incorporation of HRVWI findings as well. Forty-nine subjects were recruited into the study. The median age of the population was 42years (range 11 to 75) with 69% being males. Incorporation of HRVWI findings classified 38.8% subjects into intracranial atherosclerotic disease (ICAD), 32.6% as stroke of other determined aetiology (ODE) (inflammatory vasculopathy [IVas] being the major subgroup [81.2%]) and 28.6% into stroke of undetermined aetiology (UE). HRVWI enabled a diagnostic reclassification in an additional 47.3% among the baseline UE category as against luminal imaging findings alone. ICAD was likelier to have eccentric vessel wall thickening, eccentric vessel wall enhancement and T2 juxtaluminal hyperintensity with surrounding hypointensity (P < 0.001), while IVas were more likely to exhibit concentric vessel wall thickening with homogenous enhancement (P < 0.001). HRVWI is a useful noninvasive adjunctive tool in the diagnostic evaluation of intracranial vasculopathies, with maximum benefit in ICAD and IVas subtypes.

Clinical interpretation of high-resolution vessel wall MRI of intracranial arterial diseases.

Intracranial arterial pathology has traditionally been evaluated with luminal imaging. Recently, high-resolution vessel wall imaging (HR-VWI) with MRI has facilitated submillimetre evaluation of the arterial walls. This technique can help differentiate various causes of intracranial steno-occlusive disease, identify culprit atherosclerotic plaques with a recent cerebral infarct, locate vessel wall pathology in areas with minimal or no narrowing on luminal imaging, predict aneurysm stability and identify a ruptured aneurysm when multiple aneurysms are present. Interpretation of HR-VWI examinations requires a solid understanding of the pathophysiology, clinical features, serum and cerebrospinal fluid laboratory findings, treatment administered and fundamental patterns of VWI abnormalities that may be encountered with the intracranial vasculopathies. This pictorial essay aimed to illustrate the essential findings of common conditions encountered with HR-VWI including intracranial atherosclerosis, moyamoya disease, intracranial vasculitis, varicella zoster vasculopathy, reversible cerebral vasoconstriction syndrome and aneurysms.

Postmortem Study of Validation of Low Signal on Fat-Suppressed T1-Weighted Magnetic Resonance Imaging as Marker of Lipid Core in Middle Cerebral Artery Atherosclerosis.

Background and Purpose—High signal on T1-weighted fat-suppressed images in middle cerebral artery plaques on ex vivo magnetic resonance imaging was verified to be intraplaque hemorrhage histologically. However, the underlying plaque component of low signal on T1-weighted fat-suppressed images (LST1) has never been explored. Based on our experience, we hypothesized that LST1 might indicate the presence of lipid core within intracranial plaques.Methods—1.5 T magnetic resonance imaging was performed in the postmortem brains to scan the cross sections of bilateral middle cerebral arteries. Then middle cerebral artery specimens were removed for histology processing. LST1 presence was identified on magnetic resonance images, and lipid core areas were measured on the corresponding histology sections.Results—Total 76 middle cerebral artery locations were included for analysis. LST1 showed a high specificity (96.9%; 95% confidence interval, 82.0%–99.8%) but a low sensitivity (38.6%; 95% confidence interval, 24.7%–54.5%) for detecting lipid core of all areas. However, the sensitivity increased markedly (81.2%; 95% confidence interval, 53.7%–95.0%) when only lipid cores of area ≥0.80 mm2 were included. Mean lipid core area was 5× larger in those with presence of LST1 than in those without (1.63±1.18 mm2 versus 0.32±0.31 mm2; P=0.003).Conclusions—LST1 is a promising imaging biomarker of identifying intraplaque lipid core, which may be useful to distinguish intracranial atherosclerotic disease from other intracranial vasculopathies and to assess plaque vulnerability for risk stratification of patients with intracranial atherosclerotic disease. In vivo clinical studies are required to explore the correlation between LST1 and clinical outcomes of patients with intracranial atherosclerotic disease.

High-resolution Magnetic Resonance Vessel Wall Imaging for Intracranial Arterial Stenosis

Objective:To discuss the feasibility and clinical value of high-resolution magnetic resonance vessel wall imaging (HRMR VWI) for intracranial arterial stenosis.Date Sources:We retrieved information from PubMed database up to December 2015, using various search terms including vessel wall imaging (VWI), high-resolution magnetic resonance imaging, intracranial arterial stenosis, black blood, and intracranial atherosclerosis.Study Selection:We reviewed peer-reviewed articles printed in English on imaging technique of VWI and characteristic findings of various intracranial vasculopathies on VWI. We organized this data to explain the value of VWI in clinical application.Results:VWI with black blood technique could provide high-quality images with submillimeter voxel size, and display both the vessel wall and lumen of intracranial artery simultaneously. Various intracranial vasculopathies (atherosclerotic or nonatherosclerotic) had differentiating features including pattern of wall thickening, enhancement, and vessel remodeling on VWI. This technique could be used for determining causes of stenosis, identification of stroke mechanism, risk-stratifying patients, and directing therapeutic management in clinical practice. In addition, a new morphological classification based on VWI could be established for predicting the efficacy of endovascular therapy.Conclusions:This review highlights the value of HRMR VWI for discrimination of different intracranial vasculopathies and directing therapeutic management.

High-resolution MRI vessel wall imaging in varicella zoster virus vasculopathy

Contrast-enhanced vessel wall imaging high-resolution MRI (HRMR) has revealed vessel wall thickening and enhancement in multiple intracranial vasculopathies, including varicella zoster virus (VZV) vasculopathy. We retrospectively reviewed a database of patients with virologically-verified VZV vasculopathy, who underwent initial and follow-up HRMR between April 2011 and May 2014. Six patients were identified. Baseline demographic and clinical characteristics were collected, including stroke risk factors, history of VZV-related disorders, neurological presentation, course and antiviral treatment. Initial HRMR in patients with VZV vasculopathy demonstrated various patterns of stenosis, vessel wall thickening and enhancement, predominantly in terminal internal carotid artery segments and the M1 segment of the middle cerebral arteries. Follow-up HRMR showed improvement of stenosis, with reduced vessel wall thickening and enhancement at multiple times after treatment. HRMR has the potential to assist in diagnosis and treatment of VZV vasculopathy.

Pure arterial malformation of the posterior cerebral artery: importance of its recognition

The finding of dilated, elongated, and tortuous vessels on brain imaging should prompt clinicians to determine what vascular anomaly is present. Importantly, not all suspicious serpentine flow voids are manifestations of arteriovenous malformations or arteriovenous fistulas. Other types of intracranial vasculopathies should also be considered. The authors report a rare case of dilated, tortuous, and redundant left posterior communicating artery and left P2 segment of the posterior cerebral artery identified in a young healthy adult that remained stable over a 30-year period. Dynamic and 3D images were critical for determining the type of vascular anomaly and for guiding appropriate management. The authors propose that this case represents a pure arterial malformation and discuss its distinguishing features.

Multiple ischemic strokes in a case of Transient Cerebral Arteriopathy (TCA) following chickenpox

In children arterial ischemic strokes (AIS) are often caused by infections. VZV can lead to unilateral intracranial vasculopathies with consecutive ischemic strokes. We report on an 11 years old girl who had chickenpox 7 years before onset of neurological symptoms.

Intracranial Arterial Aneurysm Vasculopathies: Targeting the Outer Vessel Wall

Intracranial Arterial Aneurysm Vasculopathies: Targeting the Outer Vessel Wall

Intracranial arterial aneurysm vasculopathies: targeting the outer vessel wall

The pathogenesis of intracranial arterial aneurysms (AA) remains unclear, despite their clinical importance. An improved understanding of this disease is important in choosing therapeutic options. In addition to the "classical" berry-type aneurysm, there are various other types of intracranial AA such as infectious, dissecting or giant, partially-thrombosed aneurysms. From the clinician's perspective, the hypothesis that some of these intracranial AA might be due to abluminal factors has been proposed for several years. Indeed, this hypothesis and the empirical use of anti-inflammatory drugs in giant intracranial aneurysms have been confirmed by recent studies reporting that an enzyme involved in the inflammatory cascade (5-lipoxygenase or 5-LO) promotes the pathogenesis of specific aneurysms in humans. 5-LO generates different forms of leukotrienes which are potent mediators of inflammation. Adventitial inflammation leads to a weakening of the media from the abluminal part of the vessel wall due to the release of proinflammatory factors that invade the media, thereby degrading the extracellular matrix, the elastic lamina of the vascular wall, and, finally, the integrity of the vessel lumen. This in turn results in a dilation of the vessel and aneurysm formation. Moreover, neoangiogenesis of vasa vasorum is found in close proximity to 5-LO activated macrophages. In addition to this biological cascade, we argue that repeated subadventitial haemorrhages from the new vasa vasorum play an important role in aneurysm pathogenesis, due to a progressive increase in size mediated by the apposition of new layers of intramural haematoma within the vessel wall. Intracranial giant AA can therefore be regarded as a proliferative disease of the vessel wall induced by extravascular activity. Considering certain aneurysmal vasculopathies as an abluminal disease might alter current therapeutic strategies. Therapy should not only be aimed at the intraluminal repair of the artery, but also cross the vessel wall to reach the vasa vasorum. Drug-eluting stents placed proximal to the lesion and targeted to the origin of the vasa vasorum could be considered as a potential future option. "Intelligent" MRI contrast agents (i.e., macrophage marking) could be used to detect vasa vasorum proliferation and weakening of the vessel wall in vivo.