Spontaneous intracranial vertebral artery dissection with acute ischemic stroke: High-resolution magnetic resonance imaging findings

Top of basilar syndrome due to vertebral artery dissection: How high-resolution MRI and CD31 analysis of thrombus could help

INTRODUCTION AND IMPORTANCE

Vertebral artery dissection is a rare but serious condition that can lead to neurological deficits and even death. It is commonly associated with trauma or underlying vascular diseases. Top of basilar syndrome (TOBS) is a neurological condition that can result from vertebral artery dissection, either by direct ischemia or secondary occlusion due to distal embolization of injured inner vascular tissue. We here present a patient who was initially suffering from seizure then had TOBS due to a progressive vertebral artery dissection, with emphasis of high-resolution MRI imaging and immunohistochemistry study of the thrombus.

CASE PRESENTATION

A young male presented to the emergency department with sudden onset of seizure. A history of recent neck exercise was reported. The patient had gaze palsy, adduction disability, and dysarthria. High-resolution MRI showed a vertebral artery dissection with evidence of occlusion of the top of basilar artery. After the thrombectomy, a pathologic study revealed CD31[+] tissue in the thrombus, indicating an origin from dissected vertebral artery.

CLINICAL DISCUSSION AND CONCLUSION

It's important to recognize and treat vertebral artery dissection promptly due to its varying symptoms. Using high-resolution MRI at early stage and conducting pathologic analysis of CD31 on the thrombus can assist in the diagnosis, potentially leading to more precise treatment plans and better outcomes for patients.

Quantitative evaluation for intravascular structures of vertebral artery dissection with a novel zoomed high-resolution black-blood MR imaging

BACKGROUND

Although non-stroke vertebral artery dissection (VAD) is diagnosed using MRI, detecting the subtle intravascular structure remains challenging. This study aimed to evaluate the validity of quantitative intravascular scanning based on novel zoomed high-resolution black blood (Z-HB) MRI for distinguishing VAD from other vessel pathologies.

METHODS

Twenty-one patients with non-stroke VAD and 18 with symptomatic atherosclerotic plaques in their vertebral artery underwent Z-HB MRI and subsequent profile curve processing. Axial Z-HB imaging was obtained from dissected and normal segments in patients with VAD and atherosclerotic plaque in patients with ischemia. We investigated the qualitative categorization of the scanning patterns of the intravascular signals. We also evaluated the quantitative ability of each profile curve to discriminate multiple vessel pathologies by analyzing the receiver operating characteristics curves.

RESULTS

Profile curve processing of 140 Z-HB images categorized the intravascular signal patterns into luminal, asymmetrical, and omega types. The asymmetrical type included both dissecting and atherosclerotic vessels, and the omega type included dissecting and normal vessels. In the asymmetrical type, quantitative evaluation successfully distinguished intramural hematomas of VAD from atherosclerotic plaque with an area under the curve of 0.80. The intimal flap of the VAD was distinguished from the blood flow artifact of the normal vessel with an area under the curve of 0.93 in the omega type.

CONCLUSIONS

A combination of novel Z-HB MRI and profile curve processing provided an ultra-high-resolution analysis of the intravascular structure of non-stroke VAD and successfully distinguished VAD from normal vessels or atherosclerotic plaques.

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.

Vascular Injuries in Head and Neck Trauma

Blunt and penetrating vascular injuries of the head and neck can represent life-threatening emergencies that require accurate detection to prevent devastating and long-lasting consequences. Implementing appropriate screening criteria to indicate imaging studies is crucial as there is a variable latent time before the onset of clinical manifestations. Computed tomography angiography, MR imaging, and digital subtraction angiography represent the imaging modalities of choice to evaluate vascular injuries. The aim of this review is to provide a description of the different types of vascular injuries, describe the importance of each imaging modality, and recognize the imaging appearance of traumatic vessel injury.

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.

Sequential detection rates of intramural hematoma for diagnosing spontaneous intracranial artery dissection

BACKGROUND AND PURPOSE

Spontaneous intracranial artery dissection (IAD) can be definitively diagnosed by detecting intramural hematoma (IMH) on arterial wall imaging. However, evidence of a time-dependent natural history for the development of radiological findings is lacking. Therefore, this study aimed to determine when imaging detects IAD.

METHODS

We obtained data from our cohort databases between March 2011 and August 2018 on consecutive patients who had definite, probable, or possible IAD based on the multidisciplinary expert consensus criteria. We assessed IMH on initial and follow-up high-resolution three-dimensional T1-weighted imaging (HR-3D-T1WI). We retrospectively investigated the association between IMH detection and days from symptom onset to initial HR-3D-T1WI and compared the IMH detection rate with other definitive diagnostic arterial dissection findings.

RESULTS

We analyzed 106 patients (mean age = 51 ± 13 years, 31 women) with at least initial HR-3D-T1WI data. The final diagnoses were definite, probable, and possible IAD in 83, 18, and 5 patients, respectively. IMHs were observed in 63 patients (59%, 95% confidence interval [CI] = 49%-69%). Overall IMH detection rate was 55% (95% CI = 45%-64%), 20% (95% CI = 3%-60%), 40% (95% CI = 21%-64%), and 50% (95% CI = 37%-63%) on the initial HR-3D-T1WI and Days 3, 7, and 13, respectively. Among 68 patients evaluated with digital subtraction angiography and HR-3D-T1WI, IMH was confirmed more frequently than other definitive diagnostic arterial dissection findings.

CONCLUSIONS

The overall IMH detection rate on HR-3D-T1WI was >50% and peaked in 1-2 weeks. IMH was a frequently detectable finding for the diagnosis of IAD compared to other radiological findings.

Predictors of unfavorable outcome in stent-assisted coiling for symptomatic unruptured intracranial spontaneous vertebral artery dissecting aneurysms (uis-VADAs): results from a multicenter study

OBJECTIVE

To evaluate predictors of unfavorable outcome in stent-assisted coiling for symptomatic unruptured intracranial spontaneous vertebral artery dissecting aneurysms (uis-VADAs) based on 608 reconstructed lesions in 30 medical centres.

METHODS

A total of 608 patients (male:female=479:129; mean age, 53.26±10.26 years) with 608 symptomatic uis-VADAs underwent reconstructive treatments using stent(s) with coils between January 2009 and December 2015. Treatments and predictors of unfavorable outcomes were retrospectively analyzed.

RESULTS

Mainly, three methods were used to treat patients with uis-VADAs, including routine single-stent in 208 patients (such as Enterprise and others), new low-profile LVIS single stent in 107 patients, and multiple stents in 293 patients. During the median 66 months of clinical follow-up, 14 patients died, and 16 of the remaining 594 survivors had unfavorable outcomes (modified Rankin Scale score 3-5). The overall mortality rate was 2.3% (14/608), and the unfavorable outcome (mRS score 3-6) rate was 4.9% (30/608). Multivariate logistic regression analysis indicated that preprocedural ischemic infarctions (OR=3.78; 95% CI 1.52 to 9.40; p<0.01), diabetes mellitus (OR=3.74; 95% CI 1.31 to 10.68; p=0.01), and procedural complications (OR=14.18; 95% CI 5.47 to 36.80; p<0.01) were predictors of unfavorable outcome in the reconstructed VADAs.

CONCLUSIONS

This multicenter study indicated that preprocedural ischemic infarctions, diabetes mellitus, and procedural complications were related to unfavorable clinical outcomes in the reconstructed uis-VADAs.

Clinical and radiological features of medullary infarction caused by spontaneous vertebral artery dissection

BACKGROUND AND PURPOSE

Medullary infarction (MI) caused by spontaneous vertebral artery dissection (sVAD) is an important type of stroke. It is important to distinguish sVAD from other causes of stroke since the treatment strategies and prognosis were different between them. In this study, we aimed to explore the clinical and radiological features of MI in patients with acute MI caused by sVAD.

METHODS

Patients with acute MI caused by sVAD and non-sVAD in a single tertiary hospital were enrolled from 2010 to 2020. Epidemiologic, clinical and image features were collected and analysed. MI lesions were categorised into three levels rostrocaudally and four arterial groups: anteromedial, anterolateral, lateral and posterior.

RESULTS

A total of 128 patients with MI were enrolled with 47 cases of sVAD and 81 cases of non-sVAD. Patients with sVAD were younger than those with non-sVAD (med 44 years old vs 58 years old). The sVAD group was less likely to have hypertension (44.68% vs 67.90%; p=0.010) and diabetes (19.15% vs 45.69%; p=0.003), but more likely to have non-sudden onset (27.66% vs 9.87%, p=0.009), minor neck injury (19.15% vs 1.23%; p=0.001) and headache (46.81% vs 7.41%; p=0.000). Vertically, sVAD became more common in caudal medulla than in rostral medulla. Horizontally, the sVAD group was more likely to have lateral MI (91.48% vs 2.96%, p=0.000). In multivariable logistic regression analysis, age, non-sudden onset and headache were independently associated with sVAD with ORs of 0.935 (95% CI 0.892 to 0.981, p=0.006), 3.507 (95% CI 1.060 to 11.599, p=0.040) and 5.426 (95% CI 1.673 to 17.599, p=0.005).

CONCLUSION

sVAD was not uncommon in patients with MI, especially in patients with lateral MI. Young patients with headache and non-sudden onset should remind clinician the possibility of sVAD.

Atypical intracranial aneurysms: spectrum of imaging findings in computed tomography and magnetic resonance imaging

We aim to describe demographics, clinical presentation, and spectrum of CT and MRI features suggestive of atypical intracranial aneurysms. The imaging protocols used for the diagnosis of intracranial aneurysms were thoroughly reviewed, including different CT and MRI protocols. We classified atypical aneurysms according to their location, size, clinical presentation, and specific imaging features. Dissecting aneurysms are one of the causes of stroke in young adults that may show intimal flap and double lumen. Traumatic intracranial aneurysms are a rare but serious complication of head injuries. Mycotic aneurysms are small and multiple at distal branch points with a high risk of rupture. Aneurysms with vasculitis are fusiform with a wide neck at a non-branch point that may be associated with vessel wall enhancement. Atherosclerotic aneurysms are usually large fusiform that affect large arteries. Oncotic aneurysms are relatively rare. They were reported to occur in patients with left atrial myxoma. Our study represented a wide spectrum of atypical intracranial aneurysms with their detailed diagnostic imaging findings on MRI and CT including newly introduced MRI sequences, which greatly influenced early diagnosis and timely management.

A Case of Intracranial Vertebral Artery Dissection Undetected by CT, MRI, and MRA at the Onset of Headache That Caused Subarachnoid Hemorrhage Seven Days Later

Objective

We report a patient with normal imaging findings at the onset of preceding headache who developed subarachnoid hemorrhage (SAH) due to intracranial vertebral artery dissection 7 days later.

Case Presentation

A 51-year-old woman with a history of chronic headache visited our emergency outpatient department with a complaint of mild to moderate right nuchal pain. CT, MRA, and MRI (diffusion-weighted image, T2-weighted image, FLAIR, MR cisternography, and basi-parallel anatomical scanning) were normal. Seven days later, she was admitted to our hospital with sudden disturbance of consciousness. CT revealed SAH and CTA demonstrated dilatation of the right vertebral artery (VA). The dilated lesion with an intimal flap on the right VA proximal to the posterior inferior cerebellar artery was confirmed on DSA. The dilated lesion and the proximal VA were occluded endovascularly using coils. The condition of the patient improved gradually, and she was transferred to the rehabilitation hospital on day 45 with a modified Rankin Scale score of 2.

Conclusion

The clinical course of the presented case, although rare, should be kept in mind in daily clinical practice.

High-resolution vessel wall imaging after mechanical thrombectomy

OBJECTIVES

High-resolution magnetic resonance imaging has the potential of characterising arterial wall changes after endovascular mechanical thrombectomy. The purpose of this study is to evaluate high-resolution magnetic resonance imaging features of large intracranial arteries following mechanical thrombectomy.

METHODS

Patients who presented with acute ischaemic stroke due to large vessel occlusion and underwent mechanical thrombectomy were prospectively recruited. Subjects underwent high-resolution magnetic resonance imaging within 24 hours of the procedure. Magnetic resonance imaging sequences included whole brain T1 pre and post-contrast black-blood imaging, three-dimensional T2, contrast-enhanced magnetic resonance angiography and susceptibility-weighted imaging. Arterial wall enhancement was objectively assessed after normalisation with the pituitary stalk. The contrast ratio of target vessels was compared with non-affected reference vessels.

RESULTS

Twenty patients with 22 target vessels and 20 reference vessels were included in the study. Sixteen patients were treated with stentriever with or without aspiration, and four with contact aspiration only. Significantly higher arterial wall enhancement was identified on the target vessel when compared to the reference vessel (U = 22.5, P < 0.01). The stentriever group had an 82% increase in the contrast ratio of the target vessel (x̄ = 0.75 ± 0.21) when compared to the reference vessel (x̄ = 0.41 ± 0.13), whereas the contact aspiration group had a 64% increase of the contrast ratio difference between target (x̄ = 0.62 ± 0.07) and reference vessels (x̄ = 0.38 ± 0.12). Approximately 65% of patients in the stentriever group had a positive parenchymal susceptibility-weighted imaging versus 25% in the contact aspiration group. There was no statistically significant correlation between susceptibility-weighted imaging volume and the percentage increase in the contrast ratio (r_s = 0.098, P = 0.748).

CONCLUSIONS

This prospective pilot study used the objective quantification of arterial wall enhancement in determining arterial changes after mechanical thrombectomy. Preliminary data suggest that the use of stentrievers is associated with a higher enhancement as compared to reperfusion catheters.

Image Findings of Acute to Subacute Craniocervical Arterial Dissection on Magnetic Resonance Vessel Wall Imaging: A Systematic Review and Proportion Meta-Analysis

Background and Purpose: This systematic review and meta-analysis aimed to evaluate the pooled proportion of image findings of acute to subacute craniocervical arterial dissection (AD) direct signs on magnetic resonance vessel wall imaging (MR-VWI) and to identify factors responsible for the heterogeneity across the included studies.

Methods: A systematic literature search in the Ovid-MEDLINE and EMBASE databases was performed for studies published on the relevant topic before April 14, 2020. Pooled sensitivity and specificity values and their 95% confidence intervals (CIs) were calculated using bivariate random-effects modeling. Meta-regression analyses were also performed to determine factors influencing heterogeneity.

Results: Eleven articles with data for 209 patients with acute to subacute craniocervical AD who underwent MR-VWI were included in this systematic review and meta-analysis. The most common findings on MR-VWI were wall hematoma (84%; 95% CI, 71%−92%), abnormal enhancement (72%; 95% CI, 49%−88%), aneurysmal dilatation (71%, 95% CI, 53%−84%), and intimal flap or double lumen signs (49%; 95% CI, 29%−71%). Among the potential covariates of heterogeneity, the presence of contrast-enhanced T1-weighted imaging (CE-T1WI) within the MR-VWI sequence combination significantly affected the pooled proportion of the intimal flap or double lumen signs.

Conclusion: Wall hematoma and intimal flap or double lumen signs were the most common and least common direct sign image findings, respectively, on MR-VWI in patients with acute to subacute craniocervical AD. Furthermore, the absence of CE-T1WI in MR-VWI protocol was the cause of heterogeneity for the detection of the intimal flap or double lumen signs. This data may help improve MR-VWI interpretation and enhance the understanding of the radiologic diagnosis of craniocervical AD.

High-Resolution Magnetic Resonance Imaging (HR-MRI) Imaging Characteristics of Vertebral Artery Dissection with Negative MR Routine Scan and Hypoperfusion in Arterial Spin Labeling

Background

Unruptured vertebral artery dissection (VAD) that causes ischemic infarction may require anticoagulant therapy or other treatments. However, anticoagulation therapy is not recommended for patients without ischemic infarction. To date, there has been no research on the imaging characteristics of patients with ischemic hypoperfusion that have a negative routine MRI scan.

Material/Methods

Patients with suspected VAD were recruited between June 2015 and June 2020 in order to perform high-resolution magnetic resonance imaging (HR-MRI). In total, 26 patients with negative MRI routine scans that underwent arterial spin labeling (ASL) examination were included in the study. The patients were divided into the hypoperfusion group and normal group based on whether hypoperfusion was found in ASL. The clinical features and HR-MRI features between these 2 groups were analyzed.

Results

There were no statistical differences between the hypoperfusion group and normal group based on the patient’s clinical characteristics (P>0.05). According to imaging characteristics between the 2 groups, the effective lumen index and the vertebrobasilar artery minimum angle were statistically significant (P<0.001). Therefore, a vertebrobasilar artery minimum angle <90° was negatively correlated to the posterior circulation ischemia hypoperfusion, with a correlation coefficient of −0.686. The effective lumen index was also negatively correlated to the posterior circulation ischemia hypoperfusion, with a correlation coefficient of −0.671. However, the location of the dissection and other HR-MRI characteristics were not statistically significant between these 2 groups (P>0.05).

Conclusions

The hypoperfusion of posterior circulation ischemia caused by VAD is related to the effective lumen index, as well as the vertebrobasilar artery minimum angle.

Cervical artery dissection-an easily neglected cause of stroke: a case report

Background

In recent years, the incidence of stroke has gradually increased in young people. There are many reasons causing stroke, including atherosclerosis, artery embolization, and cervical artery dissection and so on. However, cervical artery dissection is a major cause of stroke in young people. We present a case of ischemic stroke caused by dissection, whose distal vascular occlusion due to detachment of the thrombosis in the right internal carotid artery.

Case presentation

A 33-year-old male patient was admitted to the hospital because of stroke. Imaging examination showed that there was no visualization of the right middle cerebral artery and there were a large number of mural thrombus in the C1 segment of the right internal carotid artery. After emergency surgery, the patient had vascular recanalization and the symptoms were significantly improved. Magnetic resonance imaging showed a high signal in the C1 segment of the right internal carotid artery, the abnormal signal disappeared after antiplatelet therapy.

Conclusions

When a patient has symptoms of stroke, we need to explore the root cause of stroke. Especially in young people, cervical artery dissection is an important reason that can’t be ignored. Through review and analysis of this case, we hope to improve the understanding of radiologists and clinicians about the cervical artery dissection, reduce the rate of misdiagnosis, and improve patients’ prognosis.

MR Intracranial Vessel Wall Imaging: A Systematic Review

The purpose of this systematic review is to identify trends and extent of variability in intracranial vessel wall MR imaging (VWI) techniques and protocols. Although variability in selection of protocol design and pulse sequence type is known, data on what and how protocols vary are unknown. Three databases were searched to identify publications using intracranial VWI. Publications were screened by predetermined inclusion/exclusion criteria. Technical development publications were scored for completeness of reporting using a modified Nature Reporting Summary Guideline to assess reproducibility. From 2,431 articles, 122 met the inclusion criteria. Trends over the last 23 years (1995-2018) show increased use of 3-Tesla MR (P < .001) and 3D volumetric T1-weighted acquisitions (P < .001). Most (65%) clinical VWI publications report achieving a noninterpolated in-plane spatial resolution of ≤.55 mm. In the last decade, an increasing number of technical development (n = 20) and 7 Tesla (n = 12) publications have been published, focused on pulse sequence development, improving cerebrospinal fluid suppression, scan efficiency, and imaging ex vivo specimen for histologic validation. Mean Reporting Summary Score for the technical development publications was high (.87, range: .63-1.0) indicating strong scientific technical reproducibility. Innovative work continues to emerge to address implementation challenges. Gradual adoption into the research and scientific community was suggested by a shift in the name in the literature from "high-resolution MR" to "vessel wall imaging," specifying diagnostic intent. Insight into current practices and identifying the extent of technical variability in the literature will help to direct future clinical and technical efforts to address needs for implementation.

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

BACKGROUND

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.

PURPOSE

We aimed to identify which intracranial vasculopathies need more data and to highlight areas of strengths and weaknesses in reporting.

DATA SOURCES

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.

DATA ANALYSIS

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.

DATA SYNTHESIS

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).

LIMITATIONS

A limitation is the heterogeneity in study designs.

CONCLUSIONS

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.

High-resolution MRI of intracranial large artery diseases: how to use it in clinical practice?

High-resolution MRI (HRMRI) has emerged as a useful tool for clinical research in recent years. Compared with traditional cranial and vessel imaging, HRMRI provides more additional valuable pathophysiology information that is helpful for the differential diagnosis of intracranial atherosclerosis, dissection and vasculitis. However, there are some points that a neurologist should keep in mind. First, although enhanced vessel wall imaging is widely applied for research purposes, it is not appropriate for routine clinical use. Any injury or inflammation within vessel wall can result in enhancement, which is unspecific for a diagnosis. Second, although plaque components identified on HRMRI arouse researchers' interest, they may have limited positive predictive value for future stroke. Ruptured plaques may have higher prevalence in asymptomatic patients than expected. More prospective observational studies are required. Third, the vessel wall morphology features remain the useful and reliable clue for a diagnosis. It is true that eccentric vessel wall lesions most likely represent atherosclerosis if vessel dissection is easily excluded. For concentric wall lesions, however, the underlying pathophysiology is complicated, either atherosclerotic or non-atherosclerotic. Fourth, HRMRI can show luminal thrombus directly and provide valuable details. All in all, when HRMRI is used by a neurologist, it should not be viewed as the only key for a diagnosis. The diagnosis should be made based on patient history, lab works, other imaging technique and even genetic examinations.