High-resolution intracranial vessel wall imaging: imaging beyond the lumen

Feasibility of Artificial Intelligence Constrained Compressed SENSE Accelerated 3D Isotropic T1 VISTA Sequence For Vessel Wall MR Imaging: Exploring the Potential of Higher Acceleration Factors Compared to Traditional Compressed SENSE

RATIONALE AND OBJECTIVES

Investigate the feasibility of using deep learning-based accelerated 3D T1-weighted volumetric isotropic turbo spin-echo acquisition (VISTA) for vessel wall magnetic resonance imaging (VW-MRI), compared to traditional Compressed SENSE and optimize acceleration factor (AF) to obtain high-quality clinical images.

METHODS

40 patients with atherosclerotic plaques in the intracranial or carotid artery were prospectively enrolled in our study from October 1, 2022 to October 31, 2023 underwent high-resolution vessel wall imaging on a 3.0 T MR system using variable Compressed SENSE (CS) AFs and reconstructed by an optimized artificial intelligence constrained Compressed SENSE (CS-AI). Images were reconstructed through both traditional CS and optimized CS-AI. Two radiologists qualitatively assessed the image quality scores of CS and CS-AI across different segments and quantitatively evaluated SNR (signal-to-noise ratio) and CNR (contrast-to-noise ratio) metrics. Paired t-tests, ANOVA, and Friedman tests analyzed image quality metrics. Written informed consent was obtained from all patients in this study.

RESULTS

CS-AI groups demonstrated good image quality scores compared to reference scans until AF up to 12 (P < 0.05). The CS-AI 10 protocol provided the best images in the lumen of both normal and lesion sites (P < 0.05). The plaque SNR was significantly higher in CS-AI groups compared to CS groups until the AF increased to 12 (P < 0.05). CS-AI protocols had higher CNR compared to CS with whichever AF on both pre-and post-contrast T1WI (P < 0.05), The CNR was highest in the CS-AI 10 protocol on pre-contrast T1WI and in CS-AI 12 on post-contrast T1WI (P < 0.05).

CONCLUSION

The study demonstrated the feasibility of using CS-AI technology to diagnose arteriosclerotic vascular disease with 3D T1 VISTA sequences. The image quality and diagnostic efficiency of CS-AI images were comparable or better than traditional CS images. Higher AFs are feasible and have potential for use in VW-MRI. The determination of standardized AFs for clinical scanning protocol is expected to help for empirical evaluation of new imaging technology.

Temporal Changes on Postgadolinium MR Vessel Wall Imaging Captures Enhancement Kinetics of Intracranial Atherosclerotic Plaques and Aneurysms

BACKGROUND AND PURPOSE

Analysis of vessel wall contrast kinetics (ie, wash-in/washout) is a promising method for the diagnosis and risk-stratification of intracranial atherosclerotic disease plaque (ICAD-P) and the intracranial aneurysm walls (IA-W). We used black-blood MR imaging or MR vessel wall imaging to evaluate the temporal relationship of gadolinium contrast uptake kinetics in ICAD-Ps and IA-Ws compared with normal anatomic reference structures.

MATERIALS AND METHODS

Patients with ICAD-Ps or IAs who underwent MR vessel wall imaging with precontrast, early postcontrast (5-15 minutes), and delayed postcontrast (20-30 minutes) 3D T1-weighted TSE sequences were retrospectively studied. ROIs of a standardized diameter (2 mm) were used to measure the signal intensities of the cavernous sinus, pituitary infundibulum, temporalis muscle, and choroid plexus. Point ROIs were used for ICAD-Ps and IA-Ws. All ROI signal intensities were normalized to white matter signal intensity obtained using ROIs of 10-mm diameter. Measurements were acquired on precontrast, early postcontrast, and delayed postcontrast 3D T1 TSE sequences for each patient.ajnr;45/9/1206/T1T1T1Table 1:MR-VWI parameters for ICAD-Ps and IAsParameterValueSequence3D TSEScan planeAxialFOV (mm)160TR/TE (ms)800/28-32BW (Hx/pixel)370θ120Acceleration2ETL42Matrix acquisition0.5 mm ×0.5 mmMatrix recon0.5 mm ×0.5 mmNo. of slices/thick120/0.5Note:-FOV indicates field of view; TR, the repetition time; TE, the echo time; BW, bandwidth; ETL, echo train length; Matrix recon, matrix reconstruction.

RESULTS

Ten patients with 17 symptomatic ICAD-Ps and 30 patients with 34 IA-Ws were included and demonstrated persisting contrast uptake (P < .001) of 7.21% and 10.54% beyond the early phase (5-15 minutes postcontrast) and in the delayed phase (20-30 minutes postcontrast) on postcontrast MR vessel wall imaging. However, normal anatomic reference structures including the pituitary infundibulum and cavernous sinus demonstrated a paradoxical contrast washout in the delayed phase. In both ICAD-Ps and IA-Ws, the greatest percentage of quantitative enhancement (>70%-90%) occurred in the early phase of postcontrast imaging, consistent with the rapid contrast uptake kinetics of neurovascular pathology.

CONCLUSIONS

Using standard MR vessel wall imaging techniques, our results demonstrate the effects of gadolinium contrast uptake kinetics in ICAD-Ps and IA-Ws with extended accumulating enhancement into the delayed phase (> 15 minutes) as opposed to normal anatomic reference structures that conversely exhibit decreasing enhancement. Because these relative differences are used to assess qualitative patterns of ICAD-P and IA-W enhancement, our findings highlight the importance of standardizing acquisition time points and MR vessel wall imaging protocols to interpret pathologic enhancement for the risk stratification of cerebrovascular pathologies.

Hemodynamic characteristics of vertebrobasilar artery fenestration combined with vertebrobasilar dolichoectasia: a study based on magnetic resonance angiography

PURPOSE

This study delves into the hemodynamic characteristics of Vertebrobasilar Artery Fenestration (VBAF) combined with Vertebrobasilar Dolichoectasia (VBD) using Magnetic Resonance Angiography (MRA). By summarizing the hemodynamic features and identifying high-risk populations, we aim to provide insights for clinical treatment.

METHODS

Utilizing MRA images as a foundation, arterial three-dimensional geometric models were constructed. A total of 22 cases were categorized into control, S, L, U, and Spiral groups, and numerical simulation analysis of the vessels was conducted using computational fluid dynamics methods.

RESULTS

Hemodynamic parameters of the VBAF combined with the VBD model were obtained, including blood flow velocity, oscillatory shear stress (OSI), wall shear stress (WSS), and aneurysm formation indicator (AFI). The V, OSI, and WSS indices of the L, U, and Spiral groups were significantly higher than those of the control group (P < 0.05). High-speed blood flow, elevated WSS, and increased OSI in these groups were concentrated at the fenestration site, with scattered distribution along the tortuous vertebral artery and basilar artery segments, accompanied by significant differences in the parameters of the bilateral vertebral arteries.

CONCLUSION

This preliminary investigation identifies the L, U, and Spiral groups as high-risk populations. Abnormal hemodynamics may lead to a vicious cycle in vascular wall pathology, increasing the likelihood of adverse events such as cerebral infarction. Clinical attention should focus on individuals within these groups and their corresponding vascular regions.

Risk Factors and Clinical Significance of Ultra-Long-Term Microischemia After Intracranial Aneurysm Embolization

INTRODUCTION

This study aimed to explore influencing factors and clinical significance of ultra-long-term microischemia following intracranial aneurysm (IA) embolization and establish a theoretical foundation for reducing both the incidence of ultra-long-term microischemia and cognitive dysfunction in patients post embolization.

METHODS

A retrospective analysis was conducted on data from 147 patients who received endovascular treatment for IAs. Patients were categorized into microischemic and control (non-microischemic) groups on the based on the findings of high-resolution magnetic resonance vessel wall imaging (HR-VWI) examinations performed 3 days postoperatively and 6 months postoperatively. Risk factors for the occurrence of ultra-long-term microischemia were determined by univariate analysis and multivariate logistic regression analysis.

RESULTS

Out of 147 patients included in the study, 51 (34.69%) developed microischemia while the remaining 96 (65.31%) did not experience this condition. Analysis revealed that factors such as sex, age, history of underlying diseases (hypertension, diabetes mellitus), aneurysmal site characteristics, the presence or absence of stenosis in the aneurysm-bearing artery, modified Fisher score at admission, Barthel's index at discharge, immunoinflammatory index at 3 days postoperatively and at the 6-month follow-up, the presence or absence of aneurysmal wall enhancement, and the presence or absence of aneurysmal lumen showed no statistically significant differences between the two groups (all P > 0.05). By contrast, variables like in operative time, rupture status of the aneurysm before surgery according to World Federation of Neurologic Surgeons (WFNS) grade, aneurysm size, number of stents used, number of guidewires and catheters used, and Evans index between the two groups were found to have statistically significant disparities between those who developed microischemia and those who did not (P < 0.05). A subsequent multivariate analysis revealed that aneurysm size, Evans index, and the number of stents used were independent risk factors for the occurrence of ultra-long-term microischemia after surgical intervention of aneurysms (P < 0.05). The receiver operating characteristic (ROC) curves of the patients were constructed on the basis of risk factors determined through multivariate logistic regression analysis. Results indicated that aneurysm size (area under ROC curve (AUC) 0.619, sensitivity 94.7%, specificity 17.1%, P = 0.049), Evans index (AUC 0.670, sensitivity 96.4%, specificity 26.8%, P = 0.004), and number of stents (AUC 0.639, sensitivity 44.6%, specificity 90.2%, P < 0.001) effectively predicted the occurrence of microischemia. The incidence of cognitive dysfunction was higher in the microischemic group than in the control group (P < 0.05), and a greater number of microischemic foci was associated with a higher incidence of cognitive dysfunction. The proportion of microschemia foci in the thalamus and basal ganglia in patients with cognitive dysfunction (60.87%) was significantly higher than that in patients without cognitive dysfunction (34.55%) (P < 0.05).

CONCLUSION

Aneurysm size, Evans index > 0.3, and the quantity of stents were independent risk factors for the occurrence of ultra-long-term microischemia after aneurysm embolization and provided good predictive performance. Cognitive dysfunction was closely associated with microischemia, with its severity increasing with an increase in the number of ischemic foci.

Risk factors for thrombotic events in systemic lupus erythematosus patients with antiphospholipid antibodies: insights from morphometric measurements of carotid arteries

Objective

To identify the correlation between thrombosis and atherosclerosis in systemic lupus erythematosus (SLE) patients with antiphospholipid antibodies (aPLs) (SLE/aPLs) through high-resolution magnetic resonance imaging (HR-MRI) of the carotid artery.

Methods

A single-center, cross-sectional study was conducted. We collected consecutive patients with SLE/aPLs and healthy controls who underwent carotid HR-MRI examinations. The morphometric characteristics of the common carotid artery (CCA), internal carotid artery (ICA), external carotid artery (ECA), and carotid bulb (Sinus) were measured, and the differences in morphometric parameters between different groups were analyzed.

Results

A total of 144 carotid arteries were analyzed. Compared with the control group, the wall area, wall thickness (WT and WTmax), and normalized wall index of CCA, ICA, ECA, and Sinus were increased in patients with SLE/aPLs, and the total vascular area (TVA) of CCA, ICA, and Sinus, and the bifurcation angle (BIFA) of ICA-ECA were also increased. A negative lupus anticoagulant (LAC) (with or without positive anticardiolipin antibody (aCL) or anti-β2glycoprotein antibody (aβ2GPI)) contributed to illustrating lower increased TVA and thickened vessel walls of CCA and ICA in SLE/aPLs patients without thrombotic events. Logistic regression analysis showed that WTmaxSinus and WTmaxGlobal were independent risk factors for thrombotic events in SLE/aPLs patients. The receiver operator characteristic curve showed that the cut-off value of WTmaxSinus was 2.855 mm, and WTmaxGlobal was 3.370 mm.

Conclusion

HR-MRI ensures the complete and accurate measurement of carotid morphometric parameters. Compared with the control group, the carotid artery in patients with SLE/aPLs is mainly characterized by diffusely thickened vessel walls, and the patients with thrombotic events showed additional higher vascular area of CCA and ICA, and BIFA of ICA-ECA without significant change in lumen area. The carotid arteries of SLE/aPLs patients with thrombotic events exhibited significant vessel wall thickening in all segments except ECA compared to those without thrombotic events. LAC-negative and non-thrombotic events distinguish relatively early atherosclerosis in the carotid arteries in patients with SLE/aPLs. Patients with SLE/aPLs that possess circumscribed thickened carotid vessel walls (>3.370 mm), particularly thickened at the Sinus (>2.855 mm), may require management strategies for the risk of thrombotic events.

Comparative meta-analysis of endovascular strategies for intracranial dissecting aneurysms: Flow diverters versus stents with or without coiling

BACKGROUND

Intracranial dissecting aneurysms present a challenging subset linked to considerable morbidity and mortality, necessitating effective therapeutic strategies to prevent complications. Traditional treatments face technical limitations, while emerging endovascular modalities like stent-assisted coiling, multiple stenting, and flow-diverting devices (FDDs) offer promise in reducing periprocedural risks and enhancing patient outcomes. The aim of this study is to compare the safety and efficacy outcomes of endovascular treatment for intracranial dissecting aneurysms using FDDs versus stents (with or without coiling).

METHODS

A systematic review and meta-analysis were conducted following established guidelines. The search included PubMed, Scopus, Web of Science, and Embase databases up to July 30, 2023. Eligible studies reporting outcomes of interest in both FDD and stent-treated groups were included, and the data was extracted and analyzed using STATA software.

RESULTS

Six studies were analyzed, involving 131 patients in the FDD group and 199 patients in the stent group. The pooled rates for favorable functional outcomes (86.8% vs. 86%), mortality (3.9% vs. 6%), adequate occlusion (79.7% vs. 86.3%), aneurysm recurrence (1.3% vs. 13.3%), in-stent stenosis/thrombosis (7% vs. 6.9%), ischemic events/infarctions (6.7% vs. 7.8%), retreatment (7% vs. 8.6%), and technical success (100% vs. 98.7%) were comparable in individuals treated with FDDs and stents (p > 0.05 in all cases). Additionally, complete occlusion rates were not significantly different between FDD (62.7%) and stent-treated patients (75.2%) (p = 0.06). However, after excluding one study in a leave-one-out analysis of the random effects meta-analysis, a significant difference in the pooled rates of this outcome was observed between the FDD (59.2%) and stent (75.2%) groups (p = 0.034).

CONCLUSION

FDDs present a promising approach for the treatment of intracranial dissecting aneurysms, yielding outcomes that are roughly comparable to stent-based methods. However, the absence of randomized trials and data limitations highlight the need for further research to enhance treatment strategies.

High-resolution magnetic resonance vessel wall imaging provides new insights into Moyamoya disease

Moyamoya disease (MMD) is a rare condition that affects the blood vessels of the central nervous system. This cerebrovascular disease is characterized by progressive narrowing and blockage of the internal carotid, middle cerebral, and anterior cerebral arteries, which results in the formation of a compensatory fragile vascular network. Currently, digital subtraction angiography (DSA) is considered the gold standard in diagnosing MMD. However, this diagnostic technique is invasive and may not be suitable for all patients. Hence, non-invasive imaging methods such as computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are often used. However, these methods may have less reliable diagnostic results. Therefore, High-Resolution Magnetic Resonance Vessel Wall Imaging (HR-VWI) has emerged as the most accurate method for observing and analyzing arterial wall structure. It enhances the resolution of arterial walls and enables quantitative and qualitative analysis of plaque, facilitating the identification of atherosclerotic lesions, vascular entrapment, myofibrillar dysplasia, moyamoya vasculopathy, and other related conditions. Consequently, HR-VWI provides a new and more reliable evaluation criterion for diagnosing vascular lesions in patients with Moyamoya disease.

Association of systemic inflammatory response index and plaque characteristics with the severity and recurrence of cerebral ischemic events

AIM

We aimed to investigate the relationship between systemic inflammatory response index (SIRI) and intracranial plaque features, as well as the risk factors related to the severity and recurrence of cerebral ischemic events.

METHODS

We enrolled 170 patients with cerebral ischemic events. Baseline demographic characteristics and laboratory indicators were collected from all participants. All patients were assessed by high-resolution magnetic resonance vessel wall imaging for culprit plaque characteristics and intracranial atherosclerotic burden. Outpatient or telephone follow-up were conducted at 1, 3, and 6 months after discharge.

RESULTS

SIRI levels were significantly associated with the enhanced plaque number (r = 0.205, p = 0.007), total plaque stenosis score (r = 0.178, p = 0.020), total plaque enhancement score (r = 0.222, p = 0.004), intraplaque hemorrhage (F = 5.630, p = 0.004), and plaque surface irregularity (F = 3.986, p = 0.021). Higher SIRI levels (OR = 1.892), total plaque enhancement score (OR = 1.392), intraplaque hemorrhage (OR = 3.370) and plaque surface irregularity (OR = 2.846) were independent risk factors for moderate-severe stroke, and these variables were significantly positively correlated with NIHSS (P < 0.05 for all). In addition, higher age (HR = 1.063, P = 0.015), higher SIRI levels (HR = 2.003, P < 0.001), and intraplaque hemorrhage (HR = 4.482, P = 0.008) were independently associated with recurrent stroke.

CONCLUSIONS

Higher SIRI levels may have adverse effects on the vulnerability and burden of intracranial plaques, and links to the severity and recurrence of ischemic events. Therefore, SIRI may provide important supplementary information for evaluating intracranial plaque stability and risk stratification of patients.

Imaging of Amyloid-beta-related Arteritis

Cerebral amyloid angiopathy (CAA) is a cerebrovascular disorder marked by the accumulation of amyloid-beta peptide (Aβ) within the leptomeninges and smaller blood vessels of the brain. CAA can be both noninflammatory and inflammatory, and the inflammatory version includes Aβ-related angiitis (ABRA). ABRA is a vasculitis of the central nervous system related to an inflammatory response to Aβ in the vascular walls, which necessitates differentiating ABRA from noninflammatory CAA, as ABRA may require immunosuppressive treatment. MR imaging is typically the most effective imaging modality of choice to screen for these conditions, and they should be obtained at varying time points to track disease progression.

Epidemiology, Pathophysiology, and Imaging of Atherosclerotic Intracranial Disease

Intracranial atherosclerotic disease (ICAD) is one of the most common causes of stroke worldwide. Among people with stroke, those of East Asia descent and non-White populations in the United States have a higher burden of ICAD-related stroke compared with Whites of European descent. Disparities in the prevalence of asymptomatic ICAD are less marked than with symptomatic ICAD. In addition to stroke, ICAD increases the risk of dementia and cognitive decline, magnifying ICAD societal burden. The risk of stroke recurrence among patients with ICAD-related stroke is the highest among those with confirmed stroke and stenosis ≥70%. In fact, the 1-year recurrent stroke rate of >20% among those with stenosis >70% is one of the highest rates among common causes of stroke. The mechanisms by which ICAD causes stroke include plaque rupture with in situ thrombosis and occlusion or artery-to-artery embolization, hemodynamic injury, and branch occlusive disease. The risk of stroke recurrence varies by the presumed underlying mechanism of stroke, but whether techniques such as quantitative magnetic resonance angiography, computed tomographic angiography, magnetic resonance perfusion, or transcranial Doppler can help with risk stratification beyond the degree of stenosis is less clear. The diagnosis of ICAD is heavily reliant on lumen-based studies, such as computed tomographic angiography, magnetic resonance angiography, or digital subtraction angiography, but newer technologies, such as high-resolution vessel wall magnetic resonance imaging, can help distinguish ICAD from stenosing arteriopathies.

Emerging Concept of Intracranial Arterial Diseases: The Role of High Resolution Vessel Wall MRI

Intracranial arterial disease (ICAD) is a heterogeneous condition characterized by distinct pathologies, including atherosclerosis. Advances in magnetic resonance technology have enabled the visualization of intracranial arteries using high-resolution vessel wall imaging (HR-VWI). This review summarizes the anatomical, embryological, and histological differences between the intracranial and extracranial arteries. Next, we review the heterogeneous pathophysiology of ICAD, including atherosclerosis, moyamoya or RNF213 spectrum disease, intracranial dissection, and vasculitis. We also discuss how advances in HR-VWI can be used to differentiate ICAD etiologies. We emphasize that one should consider clinical presentation and timing of imaging in the absence of pathology-radiology correlation data. Future research should focus on understanding the temporal profile of HR-VWI findings and developing quantitative interpretative approaches to improve the decision-making and management of ICAD.

Neuroimaging Scoring Tools to Differentiate Inflammatory Central Nervous System Small-Vessel Vasculitis: A Need for Artificial Intelligence/Machine Learning?-A Scoping Review

Neuroimaging has a key role in identifying small-vessel vasculitis from common diseases it mimics, such as multiple sclerosis. Oftentimes, a multitude of these conditions present similarly, and thus diagnosis is difficult. To date, there is no standardized method to differentiate between these diseases. This review identifies and presents existing scoring tools that could serve as a starting point for integrating artificial intelligence/machine learning (AI/ML) into the clinical decision-making process for these rare diseases. A scoping literature review of EMBASE and MEDLINE included 114 articles to evaluate what criteria exist to diagnose small-vessel vasculitis and common mimics. This paper presents the existing criteria of small-vessel vasculitis conditions and mimics them to guide the future integration of AI/ML algorithms to aid in diagnosing these conditions, which present similarly and non-specifically.

Cerebellar infarction caused by vertebral artery dissection: A case report

RATIONALE

Vertebral artery dissection is an important cause of posterior circulation ischemic stroke in young and middle-aged people. We reported a young man with cerebellar infarction caused by dissection of the right vertebral artery.

PATIENT CONCERNS

A 34-year-old man presented with intermittent dizziness, blurred vision, nausea, and transient tinnitus 10 days before admission. All these symptoms were gradually aggravated and followed by vomiting and unfavorable movement of the right limbs. All these symptoms gradually aggravated.

DIAGNOSIS

Neurological examination on admission showed ataxia of the right limbs. Magnetic resonance imaging of the head revealed a right cerebellar infarction. High-resolution vessel wall magnetic resonance imaging showed dissection of the right vertebral artery. Whole-brain CT digital subtraction angiography revealed occlusion of the third segment (V3) of the right vertebral artery. This supports the diagnosis of vertebral artery dissection.

INTERVENTIONS

The patient received anticoagulant treatment with warfarin.

OUTCOMES

After 2 weeks of treatment, the patient showed remarkably alleviated dizziness and unfavorable movement of the right limbs. After 3 months of treatment, the modified Rankin Scale score was 0. MRI of the head revealed that the original right cerebellar focus was softened, and there were no newly formed infarct foci.

LESSONS

When young and middle-aged patients without atherosclerotic risk factors encounter sudden dizziness, tinnitus, and unfavorable limb movement, vertebral artery dissection may be considered. Careful inquiry into the medical history may help make a final diagnosis. Further high-resolution vessel wall magnetic resonance imaging is an effective means to find arterial dissection. Early diagnosis and treatment for vertebral artery dissection has a favorable prognosis.

Vessel wall imaging and carotid artery stenting for recurrent cervical internal carotid artery vasospasm syndrome: illustrative case

BACKGROUND

Recurrent cervical internal carotid artery vasospasm syndrome (RCICVS) causes cerebral infarction, ocular symptoms, and occasionally chest pain accompanied by coronary artery vasospasm. The etiology and optimal treatment remain unclear.

OBSERVATIONS

The authors report a patient with drug-resistant RCICVS who underwent carotid artery stenting (CAS). Magnetic resonance angiography revealed recurrent vasospasm in the cervical segment of the internal carotid artery (ICA). Vessel wall imaging during an ischemic attack revealed vascular wall thickening of the ICA, similar to that in reversible cerebral vasoconstriction syndrome. The superior cervical ganglion was identified at the anteromedial side of the stenosis site. Coronary artery stenosis was also detected. After CAS, the symptoms of cerebral ischemia were prevented for 2 years, but bilateral ocular and chest symptoms did occur.

LESSONS

Vessel wall imaging findings suggest that RCICVS is a sympathetic nervous system-related disease. CAS could be an effective treatment for drug-resistant RCICVS to prevent cerebral ischemic events.

The Use of Intracranial Vessel Wall Imaging in Clinical Practice

Three-dimensional vessel wall MR imaging has gained popularity in the diagnosis and management of patients with cerebrovascular disease in clinical practice. Vessel wall MR imaging is an imaging technique that delivers a fundamentally different viewpoint by emphasizing on the pathology of the vessel wall as opposed to traditional descriptions that focus on the vessel lumen. It shows a crucial power in detecting vessel wall changes in patients with diseases including, but not limited to, central nervous system vasculitis, moyamoya disease, aneurysms, dissections, and intracranial atherosclerotic disease.

Vessel Wall Imaging in Cryptogenic Stroke

Cryptogenic strokes are symptomatic cerebral ischemic infarcts without a clear etiology identified following standard diagnostic evaluation and currently account for 10% to 40% of stroke cases. Continued research is needed to identify and bridge gaps in knowledge of this stroke grouping. Vessel wall imaging has increasingly shown its utility in the diagnosis and characterization of various vasculopathies. Initial promising evidence suggests rational use of vessel wall imaging in stroke workup may unravel pathologies that otherwise would have been occult and further improve our understanding of underlying disease processes that can translate into improved patient outcomes and secondary stroke prevention.

The Role of High-Resolution Magnetic Resonance Imaging in Cerebrovascular Disease: A Narrative Review

High-resolution magnetic resonance imaging (HRMRI) is the most important and popular vessel wall imaging technique for the direct assessment of vessel wall and cerebral arterial disease. It can identify the cause of stroke in high-risk plaques and differentiate the diagnosis of head and carotid artery dissection, including inflammation, Moya Moya disease, cerebral aneurysm, vasospasm after subarachnoid hemorrhage, reversible cerebral vasoconstriction syndrome, blunt cerebrovascular injury, cerebral arteriovenous malformations, and other stenosis or occlusion conditions. Through noninvasive visualization of the vessel wall in vitro, quantified assessment of luminal stenosis and pathological features of the vessel wall can provide clinicians with further disease information. In this report, technical considerations of HRMRI are discussed, and current clinical applications of HRMRI are reviewed.

Clinical application of three-dimensional T1-weighted BrainVIEW in magnetic resonance imaging of cerebral venous thrombosis: a case report and literature review

To date, there is no clinical scoring system or laboratory indicator that can rule out cerebral venous thrombosis (CVT) or provide diagnostic proof for evaluating post-treatment thrombosis recanalization during follow-up. We therefore explored an imaging method for quantitative assessment of CVT and assessed thrombotic changes during follow-up. A patient presented with severe posterior occipital distension extending to the top of the forehead and an elevated plasma D-dimer (DD2) level. Computed tomography and pre-contrast-enhanced magnetic resonance imaging revealed only a small amount of cerebral hemorrhage. Three-dimensional (3D) T1-weighted (T1W) BrainVIEW pre-contrast-enhanced magnetic resonance scanning showed subacute thrombosis in the venous sinus, and the post-contrast-enhanced scan combined with volume rendering reconstruction showed cerebral thrombosis of the venous sinus and allowed for measurement of the thrombus volume. On days 30 and 60 of post-treatment follow-up, post-contrast-enhanced scans showed progressive reduction of the thrombus volume as well as recanalization and fibrotic flow voids in the chronic thrombosis. 3D T1W BrainVIEW was helpful to observe the size of the thrombi and the situation of venous sinus recanalization during the follow-up after clinical treatment of CVT. This technique can reflect the imaging manifestations of CVT throughout the whole process to guide clinical treatment decisions.

Efficacy of medical treatment and balloon angioplasty for severe intracranial atherosclerosis: a high-resolution MR vessel wall imaging

OBJECTIVES

To investigate the efficacy of medical treatment and balloon angioplasty for intracranial atherosclerosis using high-resolution MR vessel wall imaging (HR-MRI).

METHODS

In this prospective study, patients with symptomatic severe stenosis from January 2018 to August 2021 were treated with medical treatment or balloon angioplasty. The patients underwent HR-MRI at baseline and at 3, 6, and 12 months. Plaque characteristics at follow-up were compared with those at baseline using paired sample T-test or Wilcoxon rank sum test. The difference in the recurrence of ischemic events between two groups was compared.

RESULTS

A total of 37 patients (26 males; mean age = 60.5 ± 11.6 years) were evaluated. Of 68 plaques, 42 (61.8%) were treated with medication only. At 12 months of medical treatment, maximum plaque length (p = 0.004), maximum wall thickness (p = 0.036), and plaque enhancement (p = 0.001) were significantly reduced than baseline. At 3 months after balloon angioplasty, luminal stenosis (p = 0.048) was significantly reduced compared to baseline. At 6 months after balloon angioplasty, maximum plaque length (p = 0.011), maximum wall thickness (p = 0.003), and luminal stenosis (p = 0.001) were significantly reduced than baseline. No difference was found in the recurrence of ischemic events between two groups (p = 0.458).

CONCLUSION

Intracranial atherosclerotic plaque shrank and tended to be stable at 12 months of medical treatment. Plaque burden was significantly reduced 6 months after balloon angioplasty. This may provide evidence for the application and selection of treatment strategies for intracranial atherosclerotic disease.

KEY POINTS

• Plaque burden and plaque enhancement were significantly reduced at 12 months of medical treatment compared to baseline. • Plaque burden was significantly reduced at 6 months after balloon angioplasty compared with baseline. • No significant difference in the recurrence rate of ischemic stroke between patients treated with medication and balloon angioplasty.

MR vessel wall enhancement in a pediatric focal cerebral arteriopathy

BACKGROUND

Focal cerebral arteriopathy (FCA) is a common cause of childhood arterial ischemic stroke in previously healthy children. Although its mechanisms are poorly understood, recent studies have suggested inflammatory processes. Magnetic resonance vessel wall imaging (VWI) is a potential imaging biomarker of inflammation.

CASE DESCRIPTION

We describe the case of a 7-year-old Japanese girl with right hemiplegia and dysarthria for 3 days. Brain MRI showed acute infarct in the left basal ganglia, and MRA and conventional cerebral angiogram detected vascular stenosis in the left distal internal carotid artery, left M1 and A1 segments. VWI revealed marked vessel wall enhancement and thickening in the left carotid artery, M1, and A2 segments. Based on imaging findings, she was diagnosed with acute ischemic stroke caused by FCA. Because VWI findings were thought to suggest vessel wall inflammation, high-dose steroid therapy was administered in addition to neuroprotective care and antithrombotic therapy. Although her clinical symptoms improved immediately, cerebral arteriopathy worsened on MRA a month after the onset. Subsequently, after 3 months of steroid therapy, vessel wall enhancement on VWI decreased, while arterial stenosis partially improved. At the follow-up 9 months after the onset, she had no recurrent stroke, her arteriopathy had stabilized.

DISCUSSION

Definitive evidence of inflammatory mechanisms in FCA is limited, and appropriate management and treatment strategies for FCA are undefined. VWI attempts to demonstrate pathologic processes within the vessel wall, and reversible wall enhancement observed in our patient suggested the presence of inflammation. VWI would help in the evaluation of disease activity in FCA.

CONCLUSION

VWI may contribute to the appropriate diagnosis and treatment for FCA to reflect active inflammation. Further work is needed to assess the utility of VWI in pediatric FCA.

Advanced cross-sectional imaging of cerebral aneurysms

While the rupture rate of cerebral aneurysms is only 1% per year, ruptured aneurysms are associated with significant morbidity and mortality, while aneurysm treatments have their own associated risk of morbidity and mortality. Conventional markers for aneurysm rupture include patient-specific and aneurysm-specific characteristics, with the development of scoring systems to better assess rupture risk. These scores, however, rely heavily on aneurysm size, and their accuracy in assessing risk in smaller aneurysms is limited. While the individual risk of rupture of small aneurysms is low, due to their sheer number, the largest proportion of ruptured aneurysms are small aneurysms. Conventional imaging techniques are valuable in characterizing aneurysm morphology; however, advanced imaging techniques assessing the presence of inflammatory changes within the aneurysm wall, hemodynamic characteristics of blood flow within aneurysm sacs, and imaging visualization of irregular aneurysm wall motion have been used to further determine aneurysm instability that otherwise cannot be characterized by conventional imaging techniques. The current manuscript reviews conventional imaging techniques and their value and limitations in cerebral aneurysm characterization, and evaluates the applications, value and limitations of advanced aneurysm imaging and post-processing techniques including intracranial vessel wall MRA, 4D-flow, 4D-CTA, and computational fluid dynamic simulations.

High resolution 7T MR imaging in characterizing culprit intracranial atherosclerotic plaques

BACKGROUND

Current imaging modalities underestimate the severity of intracranial atherosclerotic disease (ICAD). High resolution vessel wall imaging (HR-VWI) MRI is a powerful tool in characterizing plaques. We aim to show that HR-VWI MRI is more accurate at detecting and characterizing intracranial plaques compared to digital subtraction angiography (DSA), time-of-flight (TOF) MRA, and computed tomography angiogram (CTA).

METHODS

Patients with symptomatic ICAD prospectively underwent 7T HR-VWI. We calculated: degree of stenosis, plaque burden (PB), and remodeling index (RI). The sensitivity of detecting a culprit plaque for each modality as well as the correlations between different variables were analyzed. Interobserver agreement on the determination of a culprit plaque on every imaging modality was evaluated.

RESULTS

A total of 44 patients underwent HR-VWI. Thirty-four patients had CTA, 18 TOF-MRA, and 18 DSA. The sensitivity of plaque detection was 88% for DSA, 78% for TOF-MRA, and 76% for CTA. There's significant positive correlation between PB and degree of stenosis on HR-VWI MRI (p < 0.001), but not between PB and degree of stenosis in DSA (p = 0.168), TOF-MRA (p = 0.144), and CTA (p = 0.253). RI had a significant negative correlation with degree of stenosis on HR-VWI MRI (p = 0.003), but not on DSA (p = 0.783), TOF-MRA (p = 0.405), or CTA (p = 0.751). The best inter-rater agreement for culprit plaque detection was with HR-VWI (p = 0.001).

CONCLUSIONS

The degree of stenosis measured by intra-luminal techniques does not fully reflect the true extent of ICAD. HR-VWI is a more accurate tool in characterizing atherosclerotic plaques and may be the default imaging modality in clinical practice.

Case report: Moyamoya disease, the culprit in an adult female presenting with left sided numbness

RATIONALE

Moyamoya disease is a rare progressive cerebrovascular disease that is characterized by stenosis of the vascular branches of the internal carotid artery and the development of abnormal, fragile collateral vessels. Patients with Moyamoya disease mainly present with signs and symptoms of cerebral ischemia or cerebral hemorrhage with a typically progressive course.

PATIENT CONCERNS

Here, we present a case of an adult female presenting with left sided upper and lower limb numbness.

DIAGNOSES

Diagnosis is through cerebral angiographic images demonstrating the characteristic look of collateral vessels classically present in Moyamoya disease. In this case, initial angiographic imaging along with high-resolution vessel wall brain magnetic imaging were used to diagnose the patient with this disease.

INTERVENTIONS

The patient was advised for surgical intervention; however, they were reluctant.

OUTCOMES

The patient was treated conservatively and advised for follow-up.

LESSONS

This case highlights the importance of considering Moyamoya disease in the differential diagnosis of patients presenting with sudden neurological symptoms. High-resolution vessel wall MRI is a useful tool to diagnose this disease.

Improved Blood Suppression of Motion-Sensitized Driven Equilibrium in High-Resolution Whole-Brain Vessel Wall Imaging: Comparison of Contrast-Enhanced 3D T1-Weighted FSE with Motion-Sensitized Driven Equilibrium and Delay Alternating with Nutation for Tailored Excitation

BACKGROUND AND PURPOSE

High-resolution vessel wall MR imaging is prone to slow-flow artifacts, particularly when gadolinium shortens the T1 relaxation time of blood. This study aimed to determine the optimal preparation pulses for contrast-enhanced high-resolution vessel wall MR imaging.

MATERIALS AND METHODS

Fifty patients who underwent both motion-sensitized driven equilibrium and delay alternating with nutation for tailored excitation (DANTE) preparation pulses with contrast-enhanced 3D-T1-FSE were retrospectively included. Qualitative analysis was performed using a 4-grade visual scoring system for black-blood performance in the small-sized intracranial vessels, overall image quality, severity of artifacts, and the degree of blood suppression in all cortical veins as well as transverse sinuses. Quantitative analysis of the M1 segment of the MCA was also performed.

RESULTS

The qualitative analysis revealed that motion-sensitized driven equilibrium demonstrated a significantly higher black-blood score than DANTE in contrast-enhanced 3D-T1-FSE of the A3 segment (3.90 versus 3.58, P < .001); M3 (3.72 versus 3.26, P = .004); P2 to P3 (3.86 versus 3.64, P = .017); the internal cerebral vein (3.72 versus 2.32, P < .001); and overall cortical veins (3.30 versus 2.74, P < .001); and transverse sinuses (2.82 versus 2.38, P < .001). SNR_lumen, contrast-to noise ratio_wall-lumen, and SNR_wall in the M1 vessel were not significantly different between the 2 preparation pulses (all, P > .05).

CONCLUSIONS

Motion-sensitized driven equilibrium demonstrated improved blood suppression on contrast-enhanced 3D-T1-FSE in the small intracranial arteries and veins compared with DANTE. Motion-sensitized driven equilibrium is a useful preparation pulse for high-resolution vessel wall MR imaging to decrease venous contamination and suppress slow-flow artifacts when using contrast enhancement.

Association of dissection features and primary collateral circulation with ischemic stroke in patients with spontaneous internal carotid artery dissection: evaluated using vessel wall-MRI and MRA

OBJECTIVE

To study the ischemic stroke risk factors in spontaneous internal carotid artery dissection (ICAD) patients via analyzing the dissection features and primary collateral circulation using vessel wall-MRI and magnetic resonance angiography.

METHODS

ICAD patients who had undergone VW-MRI were included in this study. A total of 36 patients were included and divided into ICAD stroke (N = 23) and non-stroke (N = 13) group. Dissection imaging features [intramural hematoma (IMH), length of IMH, intimal flap, double lumen, intraluminal thrombus, degree of stenosis] and primary collateral status were analyzed. The primary collateral score (0-4) was evaluated based on presence of anterior communicating and ipsilateral anterior cerebral artery A1 segment (0-2) and ipsilateral posterior communicating artery (0-2).

RESULTS

There were no significant differences in dissection imaging features such as presence of double lumen, intimal flap, IMH, length of IMH and intraluminal thrombus between the two groups. Degree of stenosis and primary collateral score showed significant differences between the two groups.

CONCLUSION

Both the poor primary collateral circulation and severe stenosis may play an important role in occurrence of ischemic stroke for spontaneous ICAD patients and good primary collateral circulation can help to reduce the incidence of infarction.

ADVANCES IN KNOWLEDGE

ICAD is one of the major causes of ischemic stroke. Early evaluation of the status of the Circle of Willis in ICAD patients by MRI may help to make treatment strategies and improve clinical outcome.

Diagnostic accuracy of MR vessel wall imaging at 2 weeks to predict morphological healing of vertebral artery dissection

OBJECTIVES

The spontaneous healing of non-hemorrhagic intracranial vertebral artery dissection (VAD) may be associated with the stabilization of intramural hematoma (IMH). We previously suggested that the signal intensity of IMH increases until approximately 2 weeks in VAD with spontaneous healing. We herein investigated the diagnostic accuracy of the signal intensity of IMH at 2 weeks to predict the spontaneous healing of VAD.

METHODS

From April 2017 to April 2021, we prospectively investigated patients with non-hemorrhagic VAD who underwent vessel wall imaging (VWI). Morphological healing of VAD was evaluated by MR angiography three months after its onset. The relative signal intensity (RSI) of IMH against the posterior cervical muscle on VWI was calculated. Univariate and multivariate analyses were performed on factors associated with the spontaneous healing of VAD among patient baseline data, vascular morphology at the diagnosis, and RSI parameters.

RESULTS

Forty-eight patients (23 men and 25 women; mean age: 51 years, range: 34-73 years) with 50 non-hemorrhagic VAD were included in the present study. Spontaneous healing was observed in 28 VAD (56%). RSI two weeks after the onset of VAD (RSI_2w) and morphological feature such as the string sign were associated with spontaneous healing, respectively. The multivariate logistic regression analysis identified RSI_2w as an independent predictive factor of spontaneous healing (OR: 7.3; 95% CI, 1.9-28, p = 0.004). The cut-off value for RSI_2w to predict spontaneous healing was 1.22 (AUC = 0.90, sensitivity: 91%, specificity: 82%).

CONCLUSION

RSI_2w predicted the spontaneous healing of non-hemorrhagic VAD 3 months after its onset.

Sex Differences in Intracranial Atherosclerotic Plaques Among Patients With Ischemic Stroke

Objective

High-risk intracranial arterial plaques are the most common cause of ischemic stroke and their characteristics vary between male and female patients. However, sex differences in intracranial plaques among symptomatic patients have rarely been discussed. This study aimed to evaluate sex differences in intracranial atherosclerotic plaques among Chinese patients with cerebral ischemia.

Methods

One hundred and ten patients who experienced ischemic events underwent 3T cardiovascular magnetic resonance vessel wall scanning for the evaluation of intracranial atherosclerotic disease. Each plaque was classified according to its likelihood of causing a stroke (as culprit, uncertain, or non-culprit). The outer wall area (OWA) and lumen area of the lesion and reference sites were measured, and the wall and plaque areas, remodeling ratio, and plaque burden (characterized by a normalized wall index) were further calculated. The composition (T1 hyperintensity, enhancement) and morphology (surface irregularity) of each plaque were analyzed. Sex differences in intracranial plaque characteristics were compared between male and female patient groups.

Results

Overall, 311 plaques were detected in 110 patients with ischemic stroke (81 and 29 male and female patients, respectively). The OWA (P &lt; 0.001) and wall area (P &lt; 0.001) of intracranial arterial lesions were significantly larger in male patients. Regarding culprit plaques, the plaque burden in male patients was similar to that in female patients (P = 0.178, odds ratio [OR]: 0.168, 95% confidence interval [CI]: −0.020 to 0.107). However, the prevalence of plaque T1 hyperintensity was significantly higher than that in female patients (P = 0.005, OR: 15.362, 95% CI: 2.280–103.49). In the overall ischemic stroke sample, intracranial T1 hyperintensity was associated with male sex (OR: 13.480, 95% CI: 2.444–74.354, P = 0.003), systolic blood pressure (OR: 1.019, 95% CI: 1.002–1.036, P = 0.031), and current smoker (OR: 3.245, 95% CI: 1.097–9.598, P = 0.033).

Conclusion

For patients with ischemic stroke, the intracranial plaque burden in male patients was similar to that in female patients; however, the plaque characteristics in male patients are associated with higher risk, especially in culprit plaques.

Atorvastatin for unruptured intracranial vertebrobasilar dissecting aneurysm (ATREAT-VBD): protocol for a randomised, double-blind, blank-controlled trial

INTRODUCTION

Vertebrobasilar dissecting aneurysms (VBDAs) are associated with serious complications and a poor prognosis. It is believed that inflammation of the aneurysm wall may be the main cause of rupture or deterioration. Atorvastatin has been shown to inhibit inflammation and may be a suitable drug candidate. Here, we report a clinical research study protocol to investigate whether atorvastatin inhibits inflammation of the aneurysm wall, as measured by signal index enhancement.

METHODS AND ANALYSIS

We have designed a single-centre, randomised, double-blind, blank-controlled clinical trial. 40 patients with non-ruptured VBDAs with enhancement aneurysm walls will be enrolled in Beijing Tiantan Hospital. Eligible patients will be randomly divided into two treatment groups, at a ratio of 1:1, to receive atorvastatin 20 mg orally for 6 months or no treatment. The primary assessment outcome will be the change in aneurysm wall enhancement, as measured by the signal index during the 6-month treatment period. The secondary assessment outcomes will be the aneurysm morphology (intramural haematoma, dissection valve and false lumen) and changes in the concentrations of inflammatory factors, including C reactive protein, tumour necrosis factor-α, interleukin (IL)-1β and IL-6.

ETHICS AND DISSEMINATION

The protocol has been approved by the medical ethics committee of the Beijing Tiantan Hospital at which the work will be conducted (Approval No. KY 2019-024-02). Written informed consent will be obtained from all participants. Findings from the study will be submitted for publication in a peer-reviewed journal.

TRIAL REGISTRATION NUMBER

NCT04943783.

MRA-free intracranial vessel localization on MR vessel wall images

Analysis of vessel morphology is important in assessing intracranial atherosclerosis disease (ICAD). Recently, magnetic resonance (MR) vessel wall imaging (VWI) has been introduced to image ICAD and characterize morphology for atherosclerotic lesions. In order to automatically perform quantitative analysis on VWI data, MR angiography (MRA) acquired in the same imaging session is typically used to localize the vessel segments of interest. However, MRA may be unavailable caused by the lack or failure of the sequence in a VWI protocol. This study aims to investigate the feasibility to infer the vessel location directly from VWI. We propose to synergize an atlas-based method to preserve general vessel structure topology with a deep learning network in the motion field domain to correct the residual geometric error. Performance is quantified by examining the agreement between the extracted vessel structures from the pair-acquired and alignment-corrected angiogram, and the estimated output using a cross-validation scheme. Our proposed pipeline yields clinically feasible performance in localizing intracranial vessels, demonstrating the promise of performing vessel morphology analysis using VWI alone.

Moyamoya Vasculopathy: Cause, Clinical Manifestations, Neuroradiologic Features, and Surgical Management

In moyamoya disease, the progressive occlusion of the distal portion of the internal carotid artery and its major branches is typically responsible for the formation of an extensive network of collateral vessels at the base of the brain. When moyamoya collateral network develops in association with various systemic or acquired diseases, the term moyamoya syndrome is used to denote this phenomenon. Sudden changes in the supraclinoid internal carotid artery and middle cerebral artery can be recognized with noninvasive neurovascular imaging techniques, which also allow a differential diagnosis with similar diseases such as degenerative steno-occlusive disease, cerebral vasculitis, and twig-like middle cerebral artery. Once the diagnosis is established, the definitive treatment for moyamoya disease is surgical revascularization, with the goal of increasing cerebral blood flow and preventing recurrent stroke. We provide a comprehensive review of the clinical and radiologic features in moyamoya vasculopathy along with its surgical management.

The Added Value of Vessel Wall MRI in the Detection of Intraluminal Thrombus in Patients Suspected of Craniocervical Artery Dissection

Patients with craniocervical artery dissection (CCAD) have a high short-term risk of ischemic stroke, which is frequently associated with thromboembolism. Previous studies have demonstrated the utility of three-dimensional vessel wall MR imaging (3D-VWMRI) in the diagnosis of dissection. Few have investigated the value of 3D-VWMRI in the detection of intraluminal thrombus. The purpose of the current study was to evaluate the added value of 3D-VWMRI for thrombus identification in patients suspected of CCAD. One hundred and four patients (mean age, 44.2 years ± 13.2) suspected of CCAD and scheduled for digital subtraction angiography (DSA) were prospectively enrolled in the study and underwent VWMRI examination. The diagnostic performance of 3D-VWMRI for CCAD was evaluated using receiver operating characteristic (ROC) analysis with the final diagnosis results as the reference. The presence/absence of intraluminal thrombus on 3D-VWMRI/DSA was independently determined. The sensitivity and specificity of 3D-VWMRI for intraluminal thrombus detection were assessed with DSA serving as the reference. The odds ratio (OR) was used to evaluate the correlation between thrombus presented on 3D-VWMRI/DSA and ischemic stroke. The 3D-VWMRI had high sensitivity (90.0%) and specificity (94.3%) in identifying arteries with CCAD. The area under the ROC curve was 0.96. With DSA as the reference, the sensitivity and accuracy of 3D-VWMRI for the detection of intraluminal thrombus were 97.4% and 79.0%, respectively. An intraluminal thrombus present on 3D-VWMRI was strongly associated with a territorial ischemic stroke (OR: 30.0; 95% confidence interval: 9.1-98.4; P < .001). In conclusion, 3D-VWMRI with a 3.0-T MR system had a high diagnostic performance for CCAD and offered added value for detecting intraluminal thrombus.

The Use of Intracranial Vessel Wall Magnetic Resonance Imaging to Detect a Presumptive Syphilitic Brain Aneurysm

ABSTRACT

Syphilitic intracranial aneurysm is a rare presentation of meningovascular syphilis in developed countries. In this case report, we discuss the utilization of the intracranial vessel wall magnetic resonance imaging in the management of a patient with a rare fusiform brain aneurysm, positive syphilis serologies, and inconclusive cerebrospinal fluid findings.

Vessel Wall MR Imaging in the Pediatric Head and Neck

Vessel wall MR imaging (VWI) is a technique that progressively has gained traction in clinical diagnostic applications for evaluation of intracranial and extracranial vasculopathies, with increasing use in pediatric populations. The technique has shown promise in detection, differentiation, and characterization of both inflammatory and noninflammatory vasculopathies. In this article, optimal techniques for intracranial and extracranial VWI as well as applications and value for pediatric vascular disease evaluation are discussed.

Combined Assessment of Elevated Plasma Lipoprotein-Associated Phospholipase A2 and Plaque Enhancement Improved Accuracy in the Risk of Acute Ischemic Stroke in Patients with Intracranial Artery Stenosis

PURPOSE

We evaluated the relationship between plasma lipoprotein-associated phospholipase A₂ (Lp-PLA₂) concentration and plaque characteristics in patients with intracranial artery stenosis and their clinical relevance in acute ischemic stroke.

METHODS

Eighty-seven patients with intracranial atherosclerotic stenosis (66 males, 21 females) were retrospectively enrolled. Plasma Lp-PLA₂ concentration was measured, and vessel wall magnetic resonance imaging (VW-MRI) was used to determine intracranial vascular stenosis and plaque characteristics, including plaque enhancement, surface morphology, and T₁ hyperintensity. Binary logistic regression was used to evaluate the relationship between Lp-PLA₂ concentration and plaque characteristics of intracranial artery after adjusting for demographic and confounding factors and to assess their diagnostic efficacy for the risk of acute ischemic stroke.

RESULTS

After adjustment for demographic, medication and related lipid factors, Lp-PLA₂ elevation was associated with plaque enhancement (odds ratio [OR]=12.7, 95% confidence interval [CI] 2.51-64.82, P=0.002) and surface irregularity (OR=2.9, 95% CI 1.06-7.98, P=0.038). Both Lp-PLA₂ elevation (OR=8.8, 95% CI 1.64-47.72, P=0.011) and plaque enhancement (OR=34.3, 95% CI 5.88-200.4, P=0.001) were associated with acute ischemic stroke. Receiver operating characteristic curve analysis showed that the area under the curve for Lp-PLA₂ concentration and plaque enhancement combined in the diagnosis of acute ischemic stroke was 0.884, significantly higher than that for Lp-PLA₂ concentration (0.724) and plaque enhancement (0.794) alone.

CONCLUSION

Elevated Lp-PLA₂ is associated with plaque enhancement and plaque surface irregularity. Combined assessment of Lp-PLA₂ concentration and plaque enhancement is of greater diagnostic value for the risk of acute ischemic stroke in patients with intracranial artery stenosis.

Association of residual stenosis after balloon angioplasty with vessel wall geometries in intracranial atherosclerosis

BACKGROUND

Percutaneous transluminal balloon angioplasty (PTBA) may be an alternative treatment for patients with symptomatic intracranial atherosclerotic disease (ICAD) refractory to medical treatment. This study aimed to investigate the association of vessel wall geometric characteristics on high-resolution magnetic resonance vessel wall imaging (MR-VWI) with low residual stenosis in patients with ICAD after PTBA.

METHODS

Patients with symptomatic ICAD who underwent PTBA were prospectively and consecutively enrolled. High-resolution MR-VWI was performed before the PTBA. Vessel wall geometries of the target artery, including normalized wall index (NWI: wall area/vessel area × 100%), normalized wall thickness index (NWTI: mean wall thickness/vessel radius × 100%), and remodeling index (RI) were evaluated. Low residual stenosis was defined as postprocedural stenosis degree ≤50%. Perioperative complications including symptomatic ischemic stroke/intracranial hemorrhage, death, and arterial dissection were recorded. The baseline characteristics, vessel wall geometries, and perioperative complications were compared between the patients with low residual stenosis and high residual stenosis.

RESULTS

Among 60 patients prospectively enrolled, low residual stenosis was achieved in 46 participants (77%). Three patients (5%) suffered from symptomatic ischemic stroke within 30 days. Multivariable logistic regression showed that a lower NWI and lower NWTI were associated with low residual stenosis after PTBA (adjusted OR 0.57, 95% CI 0.35 to 0.94, p=0.027; and adjusted OR 0.88, 95% CI 0.80 to 0.98, p=0.015).

CONCLUSIONS

Lower NWI and NWTI of the target artery on high-resolution MR-VWI were associated with low residual stenosis in patients with ICAD after PTBA.

Cardiovascular Risk Factors Affect Specific Segments of the Intracranial Vasculature in High-Resolution (HR) Vessel Wall Imaging (VWI)

OBJECTIVES

Luminal-based imaging have identified different risk factors for extracranial and intracranial atherosclerosis (ICAS), but these techniques are known to underestimate the true extent of the disease. High-resolution (HR) vessel wall imaging (VWI) has recently gained recognition as a valuable tool in the assessment of ICAS. The aim of this study is to determine the association between cardiovascular risk factors and specific intracranial vessel segment involvement using HR-VWI.

MATERIALS AND METHODS

From January 2017 to January 2020, consecutive patients ≥ 18 years-old undergoing HR-VWI of the brain were identified. Patients with history of primary or secondary vasculitis, reversible cerebral vasoconstriction syndrome, or moya-moya were excluded. The presence of vessel wall thickening and enhancement were assessed in the perpendicular plane for each vessel segment by two neuroradiologists. Univariate and multivariate analyses were performed to assess associations between imaging findings and cardiovascular risk factors. Interrater reliability was calculated.

RESULTS

Seventy-one patients (39 men; mean age: 55.9 years) were included. Vessel wall enhancement was seen in 39/71 (55%). A total number of 105 vessel segments demonstrated abnormal enhancement and 79/105 (75%) had an eccentric pattern. Eccentric vessel wall enhancement was independently associated with age >65 years-old in the ICA (OR 9.0, CI 2.1 - 38.2, p < 0.01) and proximal MCA (OR 4.0, CI 1.2 - 13.2, p = 0.02), and with hyperlipidemia in the posterior circulation (OR 44.0, CI2.9-661.0, p<0.01).

CONCLUSION

There is a significant association between eccentric vessel wall enhancement of the ICA and proximal MCA in patients with age > 65; and of the proximal posterior circulation (basilar - PCA1) with hyperlipidemia.

Intracranial vessel wall imaging framework - Data acquisition, processing, and visualization

OBJECTIVE

Assessment of vessel walls is an integral part in diagnosis and disease monitoring of vascular diseases such as vasculitis. Vessel wall imaging (VWI), in particular of intracranial arteries, is the domain of Magnetic Resonance Imaging (MRI) - but still remains a challenge. The tortuous anatomy of intracranial arteries and the need for high resolution within clinically acceptable scan times require special technical conditions regarding the hardware and software environments.

MATERIALS AND METHODS

In this work a dedicated framework for intracranial VWI is presented offering an optimized, black-blood 3D T1-weighted post-contrast Compressed Sensing (CS)-accelerated MRI sequence prototype combined with dedicated 3D-GUI supported post-processing tool for the CPR visualization of tortuous arbitrary vessel structures.

RESULTS

Using CS accelerated MRI sequence, the scanning time for high-resolution 3D black-blood CS-space data could be reduced to under 10 min. These data are adequate for a further processing to extract straightened visualizations (curved planar reformats - CPR). First patient data sets could be acquired in clinical environment.

CONCLUSION

A highly versatile framework for VWI visualization was demonstrated utilizing a post-processing tool to extract CPR reformats from high-resolution 3D black-blood CS-SPACE data, enabling simplified and optimized assessment of intracranial arteries in intracranial vascular disorders, especially in suspected intracranial vasculitis, by stretching their tortuous course. The processing time from about 15-20 min per patient (data acquisition and further processing) allows the integration into clinical routine.

Essentials for Interpreting Intracranial Vessel Wall MRI Results: State of the Art

Intracranial vessel wall (VW) MRI has become widely available in clinical practice, providing multiple uses for evaluation of neurovascular diseases. The Vessel Wall Imaging Study Group of the American Society of Neuroradiology has recently reported expert consensus recommendations for the clinical implementation of this technique. However, the complexity of the neurovascular system and caveats to the technique may challenge its application in clinical practice. The purpose of this article is to review concepts essential for accurate interpretation of intracranial VW MRI results. This knowledge is intended to improve diagnostic confidence and performance in the interpretation of VW MRI scans. © RSNA, 2021 Online supplemental material is available for this article.

Intracranial vessel wall imaging

PURPOSE OF REVIEW

To give an overview regarding the potential usefulness of vessel wall imaging (VWI) in distinguishing various intracranial vascular diseases, their common imaging features, and potential pitfalls.

RECENT FINDINGS

VWI provides direct visualization of the vessel wall and allows the discrimination of different diseases such as vasculitis, atherosclerosis, dissection, Moyamoya disease, and reversible cerebral vasoconstriction syndrome. Recent studies showed that concentric and eccentric involvement in the vessel wall, as well as the enhancement pattern were found important for the distinguishing these diseases and evaluating their activity.

SUMMARY

Most of the imaging techniques currently used are based on luminal imaging. However, these imaging methods are not adequate to distinguish different diseases that can demonstrate similar radiological findings. VWI is being increasingly used as a noninvasive imaging method to offset this limitation.

Diagnosis and follow-up evaluation of central nervous system vasculitis: an evaluation of vessel-wall MRI findings

Objective

To approach the clinical value of MRI with vessel wall imaging (VWI) in patients with central nervous system vasculitis (CNSV), we analyzed patterns of VWI findings both at the time of initial presentation and during follow-up.

Methods

Stenoocclusive lesions, vessel-wall contrast enhancement (VW-CE) and diffusion-restricted lesions were analyzed in patients with a diagnosis of CNSV. On available VWI follow-up, progression, regression or stability of VW-CE were evaluated and correlated with the clinical status.

Results

Of the 45 patients included, 28 exhibited stenoses visible on MR angiography (MRA-positive) while 17 had no stenosis (MRA-negative). VW-CE was found in 2/17 MRA-negative and all MRA-positive patients (p < 0.05). 79.1% (53/67) of stenoses showed VW-CE. VW-CE was concentric in 88.3% and eccentric in 11.7% of cases. Diffusion-restricted lesions were found more frequently in relation to stenoses with VW-CE than without VW-CE (p < 0.05). 48 VW-CE lesions in 23 patients were followed over a median time of 239.5 days. 13 VW-CE lesions (27.1%) resolved completely, 14 (29.2%) showed partial regression, 17 (35.4%) remained stable and 4 (8.3%) progressed. 22/23 patients received immunosuppressive therapy for the duration of follow-up. Patients with stable or progressive VW-CE were more likely (p < 0.05) to have a relapse (14/30 cases) than patients with partial or complete regression of VW-CE (5/25 cases).

Conclusion

Concentric VW-CE is a common finding in medium/large-sized vessel CNSV. VW-CE might represent active inflammation in certain situations. However, follow-up VWI findings proved ambiguous as persisting VW-CE despite immunosuppressive therapy and clinical remission was a frequent finding.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00415-021-10683-7.

Headache Emergencies

Headache is a common reason for seeking medical attention. Most cases are benign primary headache disorders; however, there is significant overlap between symptoms of these disorders and secondary headaches. Differentiating these clinical scenarios requires a careful history with attention to red flag symptoms and a neurologic examination. These details can identify dangerous disorders: subarachnoid hemorrhage, reversible cerebral vasoconstriction syndrome, elevated intracranial pressure, hydrocephalus, cerebral venous sinus thrombosis, arterial dissection, central nervous system infection, and inflammatory vasculitis. Older, pregnant, or immunocompromised patients have a higher risk for secondary disorders; clinicians should have a different threshold to conduct evaluations in such patients.

Urinary sodium and potassium excretion and cerebrovascular health: a multimodal imaging study

PURPOSE

Dietary sodium and potassium intake are associated with stroke, but the potential mechanisms are unclear. We aimed to study the association between sodium and potassium intake and subclinical cerebrovascular health in hypertensive older males using multimodal magnetic resonance imaging.

METHODS

A total of 189 hypertensive male subjects without previous cardiovascular or cerebrovascular disease were included. Daily urinary sodium and potassium excretion were estimated from a fasting spot urine sample using a formula approach. A dedicated cerebrovascular health imaging protocol including vessel wall imaging, angiography, arterial spin labeling imaging and T2-weighted fluid-attenuated inversion recovery imaging was performed to study intracranial atherosclerosis, vascular rarefaction (defined as fewer discernible vessels on angiography), brain perfusion and small vessel disease, respectively.

RESULTS

The mean age was 64.9 (± 7.2) years. The average daily urinary and potassium excretion was 4.7 (± 1.4) g/L and 2.1 (± 0.5) g/L, respectively. Increased urinary sodium excretion was associated with decreased cerebral blood flow and elevated urinary potassium excretion was associated with reduced prevalence of intracranial plaque. The associations remained significant after adjusting for covariates, even including blood pressure control. Quadratic regression analysis indicated a marginally significant U-shaped association between urinary sodium intake and white matter hyperintensity, which lost significance in fully adjusted models. No significant association of urinary sodium and potassium excretion with other cerebrovascular health measures was noted.

CONCLUSION

We concluded that in hypertensive older males without overt cardiovascular disease, increased sodium intake and reduced potassium intake are associated with impaired subclinical cerebrovascular health.

Rabbit models of intracranial atherosclerotic disease for pathological validation of vessel wall MRI

INTRODUCTION

Vessel wall magnetic resonance imaging can improve the evaluation of intracranial atherosclerotic disease. However, pathological validation is needed to improve vessel wall magnetic resonance imaging techniques. Human pathology samples are not practical for such analysis, so an animal model is therefore needed.

MATERIALS AND METHODS

Watanabe heritable hyperlipidemic rabbits and apolipoprotein E knockout rabbits were evaluated against New Zealand white wild-type rabbits. Evaluation of intracranial arteries was performed with vessel wall magnetic resonance imaging and pathological analysis, rating the presence and severity of disease in each segment. Two-tailed t-tests were performed to compare disease occurrence and severity prevalence among rabbit subtypes. Sensitivity and specificity were calculated to assess the diagnostic accuracy of vessel wall magnetic resonance imaging.

RESULTS

Seventeen rabbits (five Watanabe heritable hyperlipidemic, four apolipoprotein E knockout and eight New Zealand white) were analysed for a total of 51 artery segments. Eleven segments (five Watanabe heritable hyperlipidemic and six apolipoprotein E knockout) demonstrated intracranial atherosclerotic disease on pathology. Disease model animals had lesions more frequently than New Zealand white animals (P<0.001). The sensitivity and specificity of vessel wall magnetic resonance imaging for the detection of intracranial atherosclerotic disease were 68.8% and 95.2%, respectively. When excluding mild cases to assess vessel wall magnetic resonance imaging accuracy for detecting moderate to severe intracranial atherosclerotic disease lesions, sensitivity improved to 100% with unchanged specificity.

CONCLUSION

Intracranial atherosclerotic disease can be reliably produced and detected using 3T vessel wall magnetic resonance imaging-compatible Watanabe heritable hyperlipidemic and ApoE rabbit models. Further analysis is needed to characterize better the development and progression of the disease to correlate tissue-validated animal findings with those in human vessel wall magnetic resonance imaging studies.

High-resolution vessel wall magnetic resonance imaging for depicting imaging features of unruptured intracranial vertebrobasilar dissecting aneurysms

Objective

To demonstrate the application value of high-resolution vessel wall magnetic resonance imaging (HR-VW-MRI) for depicting the imaging features of unruptured intracranial vertebrobasilar dissecting aneurysms (VBDAs).

Methods

HR-VW-MRI data of 49 patients with suspected unruptured VBDAs were retrospectively analyzed. The presence of intramural hematomas (IMH), double lumens, intimal flaps, and outer diameter enlargements were recorded. Specificity and sensitivity were calculated for both two-dimensional (2D) and three-dimensional (3D) sequences. Additionally, IMH volumes were measured and posterior inferior cerebellar artery (PICA) involvement was analyzed.

Results

Thirty-five VBDAs were confirmed in 34 patients. The overall sensitivity and specificity were 0.889 (95% confidence interval [CI]: 0.730–0.964) and 0.769 (95% CI: 0.460–0.938) for 2D sequences, and 0.917 (95% CI: 0.764–0.978) and 0.846 (95% CI: 0.537–0.973) for 3D sequences, respectively. Intimal flaps were detected in 57.1%, 87.5%, and 71.4% of all cases on 2D pre-contrast T1-weighted, contrast-enhanced T1-weighted, and 3D T1-weighted black-blood (BB) images, respectively. There was no significant difference in IMH volume between 3D T1-weighted BB and magnetization-prepared rapid gradient-echo sequences. PICA involvement was best visualized using 3D T1 sequences.

Conclusion

3D T1-weighted BB MRI provided good visualization of VBDA features, with large coverage, and was useful for detecting dissection flaps.

Usefulness of 3D High-resolution Vessel Wall MRI in Diffuse Nonaneurysmal SAH Patients

PURPOSE

In 15-20% of patients with nontraumatic diffuse subarachnoid hemorrhage (SAH), the initial conventional angiography does not reveal a causative vascular abnormality, such as intracranial aneurysm. In this study, we evaluated clinical utility of 3D high-resolution vessel wall magnetic resonance imaging (HR-VWI) in patients with diffuse nonaneurysmal SAH.

METHODS

A total of 17 patients with diffuse nonaneurysmal SAH were included in this retrospective study. We characterized demographics and HR-VWI findings and reviewed the clinical management and outcomes.

RESULTS

Of the patients 14 (14/17; 82.4%,) showed abnormal findings on HR-VWI, including 5 with intracranial dissections (29.4%), 3 with blood blister-like aneurysm (17.6%), 1 with ruptured fusiform aneurysm (5.9%), and 5 with focal nodular wall enhancement without unclassified pathology (29.4%). Of these patients were treated with endovascular management. Most patients (16/17) had a favorable modified Rankin scale scores of 0-2 on discharge.

CONCLUSION

The 3D HR-VWI revealed various hidden pathologies, such as intracranial arterial dissection, blood blister-like aneurysm, and fusiform aneurysm in patients with diffuse nonaneurysmal SAH. In addition, 3D HR-VWI had an impact on the management of SAH. The 3D HR-VWI can be a complementary diagnostic method for patients with diffuse nonaneurysmal SAH in a research or clinical setting.

Conventional and advanced MRI evaluation of brain vascular malformations

Vascular malformations (VMs) of the central nervous system (CNS) include a wide range of pathological conditions related to intra and extracranial vessel abnormalities. Although some VMs show typical neuroimaging features, other VMs share and overlap pathological and neuroimaging features that hinder an accurate differentiation between them. Hence, it is not uncommon to misclassify different types of VMs under the general heading of arteriovenous malformations. Thorough knowledge of the imaging findings of each type of VM is mandatory to avoid these inaccuracies. Conventional MRI sequences, including MR angiography, have allowed the evaluation of CNS VMs without using ionizing radiation. Newer MRI techniques, such as susceptibility-weighted imaging, black blood sequences, arterial spin labeling, and 4D flow imaging, have an added value of providing physiopathological data in real time regarding the hemodynamics of VMs. Beyond MR images, new insights using 3D printed models are being incorporated as part of the armamentarium for a noninvasive evaluation of VMs. In this paper, we briefly review the pathophysiology of CNS VMs, focusing on the MRI findings that may be helpful to differentiate them. We discuss the role of each conventional and advanced MRI sequence for VMs assessment and provide some insights about the value of structured reports of 3D printing to evaluate VMs.

Motion-compensated 3D turbo spin-echo for more robust MR intracranial vessel wall imaging

PURPOSE

(1) To investigate the effect of internal localized movement on 3DMR intracranial vessel wall imaging and (2) to develop a novel motion-compensation approach combining volumetric navigator (vNav) and self-gating (SG) to simultaneously compensate for bulk and localized movements.

METHODS

A 3D variable-flip-angle turbo spin-echo (ie, SPACE) sequence was modified to incorporate vNav and SG modules. The SG signals from the center k-space line are acquired at the beginning of each TR to detect localized motion-affected TRs. The vNavs from low-resolution 3D EPI are acquired to identify bulk head motion. Fifteen healthy subjects and 3 stroke patients were recruited in this study. Overall image quality (0-poor to 4-excellent) and vessel wall sharpness were compared among the scenarios with and without bulk and/or localized motion and/or the proposed compensation strategies.

RESULTS

Localized motion reduced wall sharpness, which was significantly mitigated by SG (ie, outer boundary of basilar artery: 0.68 ± 0.27 vs 0.86 ± 0.17; P = .037). When motion occurred, the overall image quality and vessel wall sharpness obtained with vNav-SG SPACE were significantly higher than those obtained with conventional SPACE (ie, basilarartery outer boundary sharpness: 0.73 ± 0.24 vs 0.94 ± 0.24; P = .033), yet comparable to those obtained in motion-free scans (ie, basilarartery outer boundary sharpness: 0.94 ± 0.24 vs 0.96 ± 0.31; P = .815).

CONCLUSION

Localized movements can induce considerable artifacts in intracranial vessel wall imaging. The vNav-SG approach is capable of compensating for both bulk and localized motions.

High-Resolution Magnetic Resonance Vessel Wall Imaging for the Evaluation of Intracranial Vascular Pathology

Intracranial vessel wall imaging (IVWI) is an advanced MR imaging technique that allows for direct visualization of the walls of intracranial blood vessels and detection of subtle pathologic vessel wall changes before they become apparent on conventional luminal imaging. When performed correctly, IVWI can increase diagnostic confidence, aid in the differentiation of intracranial vasculopathies, and assist in patient risk stratification and prognostication. This review covers the essential technical underpinnings of IVWI and presents emerging clinical research highlighting its utility for the evaluation of multiple intracranial vascular pathologies.

Evaluating thunderclap headache

PURPOSE OF REVIEW

Thunderclap headache (TCH) is an abrupt-onset of severe headache that needs to be thoroughly investigated because the most common secondary cause is subarachnoid hemorrhage (SAH). There has been no consensus guideline regarding the diagnostic workup. This review aims to provide an update on the evaluation of TCH.

RECENT FINDINGS

The most important update in the 2019 American College of Emergency Physicians guideline for evaluation of acute headache in the emergency department is that negative noncontrast brain computed tomography (CT) findings within 6 h from ictus essentially excludes SAH. Additionally, the updated guideline recommends that after a negative brain CT, CT angiogram is a reasonable alternative to lumbar puncture if clinical suspicion of an intracranial source of SAH is high. An important update of reversible vasoconstriction syndrome (RCVS), the second most common etiology of TCH, is the RCVS2 score development based on clinical and radiological features, providing high specificity and sensitivity for distinguishing RCVS from other intracranial arteriopathies.

SUMMARY

Although the evaluation of TCH is exhaustive, the potentially catastrophic consequence of a missed diagnosis of sentinel headache justifies the efforts. Awareness of the clinical features and application of diagnostic tools specific for different pathological conditions can facilitate the diagnostic workup.