Effects of Chronic Inflammatory Activation of Murine and Human Arterial Endothelial Cells at Normal Lipoprotein and Cholesterol Levels In Vivo and In Vitro.

The activation of endothelial cells is crucial for immune defense mechanisms but also plays a role in the development of atherosclerosis. We have previously shown that inflammatory stimulation of endothelial cells on top of elevated lipoprotein/cholesterol levels accelerates atherogenesis. The aim of the current study was to investigate how chronic endothelial inflammation changes the aortic transcriptome of mice at normal lipoprotein levels and to compare this to the inflammatory response of isolated endothelial cells in vitro. We applied a mouse model expressing constitutive active IκB kinase 2 (caIKK2)-the key activator of the inflammatory NF-κB pathway-specifically in arterial endothelial cells and analyzed transcriptomic changes in whole aortas, followed by pathway and network analyses. We found an upregulation of cell death and mitochondrial beta-oxidation pathways with a predicted increase in endothelial apoptosis and necrosis and a simultaneous reduction in protein synthesis genes. The highest upregulated gene was ACE2, the SARS-CoV-2 receptor, which is also an important regulator of blood pressure. Analysis of isolated human arterial and venous endothelial cells supported these findings and also revealed a reduction in DNA replication, as well as repair mechanisms, in line with the notion that chronic inflammation contributes to endothelial dysfunction.

Molecular mechanisms of TACE refractoriness: Directions for improvement of the TACE procedure.

Transcatheter arterial chemoembolisation (TACE) is the standard of care for intermediate-stage hepatocellular carcinoma and selected patients with advanced hepatocellular carcinoma. However, TACE does not achieve a satisfactory objective response rate, and the concept of TACE refractoriness has been proposed to identify patients who do not fully benefit from TACE. Moreover, repeated TACE is necessary to obtain an optimal and sustained anti-tumour response, which may damage the patient's liver function. Therefore, studies have recently been performed to improve the effectiveness of TACE. In this review, we summarise the detailed molecular mechanisms associated with TACE responsiveness and relapse after this treatment to provide more effective targets for adjuvant therapy while helping to improve TACE regimens.

Protein aggregates containing wild-type and mutant NOTCH3 are major drivers of arterial pathology in CADASIL.

Loss of arterial smooth muscle cells (SMCs) and abnormal accumulation of the extracellular domain of the NOTCH3 receptor (Notch3ECD) are the 2 core features of CADASIL, a common cerebral small vessel disease caused by highly stereotyped dominant mutations in NOTCH3. Yet the relationship between NOTCH3 receptor activity, Notch3ECD accumulation, and arterial SMC loss has remained elusive, hampering the development of disease-modifying therapies. Using dedicated histopathological and multiscale imaging modalities, we could detect and quantify previously undetectable CADASIL-driven arterial SMC loss in the CNS of mice expressing the archetypal Arg169Cys mutation. We found that arterial pathology was more severe and Notch3ECD accumulation greater in transgenic mice overexpressing the mutation on a wild-type Notch3 background (TgNotch3R169C) than in knockin Notch3R170C/R170C mice expressing this mutation without a wild-type Notch3 copy. Notably, expression of Notch3-regulated genes was essentially unchanged in TgNotch3R169C arteries. We further showed that wild-type Notch3ECD coaggregated with mutant Notch3ECD and that elimination of 1 copy of wild-type Notch3 in TgNotch3R169C was sufficient to attenuate Notch3ECD accumulation and arterial pathology. These findings suggest that Notch3ECD accumulation, involving mutant and wild-type NOTCH3, is a major driver of arterial SMC loss in CADASIL, paving the way for NOTCH3-lowering therapeutic strategies.

Plaque heterogeneity and the spatial distributions of its components dictate drug-coated balloon therapy.

Drug-coated balloon (DCB) angioplasty is one of the potential approaches to alleviating in-stent restenosis and treating peripheral artery disease. An in-silico model has been developed for sirolimus drug eluted from an inflated balloon in a patient-specific arterial cross-section consisting of fibrous tissue, fibrofatty tissue, dense calcium, necrotic core, and healthy tissue. The convection-diffusion-reaction equation represents the transport of drug, while drug binding, both specific and non-specific, can be modelled as a reaction process. The Brinkman equations describe the interstitial flow in porous tissue. An image processing technique is leveraged for reconstructing the computational domain. The Marker and Cell, and Immersed Boundary Methods are used to solve the set of governing equations. The no-flux interface condition and convection do amplify the tissue content, and the regions of dense calcium and necrotic core limited to or extremely close to the interface pose a clinical threat to DCB therapy. Simulations predict the effects of the positioning and clustering of plaque components in the domain. This study demands extensive intravascular ultrasound-derived virtual histology (VH-IVUS) imaging to understand the plaque morphology and determine the relative positions of different plaque compositions about the lumen-tissue interface, which have a significant impact on arterial pharmacokinetics.

Reappraisal of large artery involvement in giant cell arteritis: a population-based cohort over 70 years.

OBJECTIVE: To evaluate the incidence and outcomes of large artery (LA) involvement among patients with giant cell arteritis (GCA) and to compare LA involvement to non-GCA patients. METHODS: The study included Olmsted County, Minnesota, USA residents with incident GCA between 1950 and 2016 with follow-up through 31 December 2020, death or migration. A population-based age-matched/sex-matched comparator cohort without GCA was assembled. LA involvement included aortic aneurysm, dissection, stenosis in the aorta or its main branches diagnosed within 1 year prior to GCA or anytime afterwards. Cumulative incidence of LA involvement was estimated; Cox models were used. RESULTS: The GCA cohort included 289 patients (77% females, 81% temporal artery biopsy positive), 106 with LA involvement.Reported cumulative incidences of LA involvement in GCA at 15 years were 14.8%, 30.2% and 49.2% for 1950-1974, 1975-1999 and 2000-2016, respectively (HR 3.48, 95% CI 1.67 to 7.27 for 2000-2016 vs 1950-1974).GCA patients had higher risk for LA involvement compared with non-GCA (HR 3.22, 95% CI 1.83 to 5.68 adjusted for age, sex, comorbidities). Thoracic aortic aneurysms were increased in GCA versus non GCA (HR 13.46, 95% CI 1.78 to 101.98) but not abdominal (HR 1.08, 95% CI 0.33 to 3.55).All-cause mortality in GCA patients improved over time (HR 0.62, 95% CI 0.41 to 0.93 in 2000-2016 vs 1950-1974) but remained significantly elevated in those with LA involvement (HR 1.89, 95% CI 1.39 to 2.56). CONCLUSIONS: LA involvement in GCA has increased over time. Patients with GCA have higher incidences of LA involvement compared with non-GCA including thoracic but not abdominal aneurysms. Mortality is increased in patients with GCA and LA involvement highlighting the need for continued surveillance.

The Contribution of Innate Immunity in Large-Vessel Vasculitis: Detangling New Pathomechanisms beyond the Onset of Vascular Inflammation.

Large-vessel vasculitis (LVV) are autoimmune and autoinflammatory diseases focused on vascular inflammation. The central core of the intricate immunological and molecular network resides in the disruption of the "privileged immune state" of the arterial wall. The outbreak, initially primed by dendritic cells (DC), is then continuously powered in a feed-forward loop by the intimate cooperation between innate and adaptive immunity. If the role of adaptive immunity has been largely elucidated, knowledge of the critical function of innate immunity in LVV is still fragile. A growing body of evidence has strengthened the active role of innate immunity players and their key signaling pathways in orchestrating the complex pathomechanisms underlying LVV. Besides DC, macrophages are crucial culprits in LVV development and participate across all phases of vascular inflammation, culminating in vessel wall remodeling. In recent years, the variety of potential pathogenic actors has expanded to include neutrophils, mast cells, and soluble mediators, including the complement system. Interestingly, new insights have recently linked the inflammasome to vascular inflammation, paving the way for its potential pathogenic role in LVV. Overall, these observations encourage a new conceptual approach that includes a more in-depth study of innate immunity pathways in LVV to guide future targeted therapies.

White matter hyperintensity burden and collateral circulation in acute ischemic stroke with large artery occlusion.

OBJECTIVE: This study aimed to investigate the association between white matter hyperintensity (WMH) burden and pial collaterals in acute strokes caused by intracranial large artery occlusion treated with mechanical thrombectomy in the anterior circulation, focusing on stroke subtypes. METHODS: Consecutive patients undergoing mechanical thrombectomy between December 2019 and June 2022 were retrospectively screened. The Fazekas scale assessed WMH burden. Pial collaterals were categorized as either poor (0-2) or good (3-4) based on the Higashida score. A multivariable analysis was used to determine the relationship between WMH burden and pial collaterals. Subgroup analyses delved into associations stratified by stroke subtypes, namely cardioembolism (CE), tandem lesions (TLs), and intracranial atherosclerosis (ICAS). RESULTS: Of the 573 patients included, 274 (47.8%) demonstrated poor pial collaterals. Multivariable regression indicated a strong association between extensive WMH burden (Fazekas score of 3-6) and poor collaterals [adjusted OR 3.04, 95% CI 1.70-5.46, P < 0.001]. Additional independent predictors of poor collaterals encompassed ICAS-related occlusion (aOR 0.26, 95% CI 0.09-0.76, P = 0.014), female sex (aOR 0.63, 95% CI 0.41-0.96, P = 0.031), and baseline Alberta Stroke Program Early Computed Tomography scores (aOR 0.80, 95% CI 0.74-0.88, P < 0.001). Notably, an interaction between extensive WMH burden and stroke subtypes was observed in predicting poor collaterals (P = 0.001), being pronounced for CE (adjusted OR 2.30, 95% CI 1.21-4.37) and TLs (adjusted OR 5.09, 95% CI 2.32-11.16), but was absent in ICAS (adjusted OR 1.24, 95% CI 0.65-2.36). CONCLUSIONS: Among patients treated with mechanical thrombectomy for anterior circulation large artery occlusion, extensive WMH burden correlates with poor pial collaterals in embolic occlusion cases (CE and TLs), but not in ICAS-related occlusion.

Feeding artery: a valuable feature for differentiation of regenerative nodule, dysplastic nodules and small hepatocellular carcinoma in CEUS LI-RADS.

OBJECTIVE: To investigate whether the feeding artery (FA) feature can aid in discriminating small hepatocellular carcinoma (HCC) using the contrast-enhanced ultrasound (CEUS) Liver Imaging Reporting and Data System (LI-RADS) from precancerous lesions. METHODS: Between June 2017 and May 2021, a total of 347 patients with 351 precancerous liver lesions or small HCCs who underwent CEUS were enrolled. Two independent radiologists assigned LI-RADS categories to all lesions and assessed the presence of the FA feature, which was used as an ancillary feature to either upgrade or downgrade the LI-RADS category. The diagnostic performance of CEUS LI-RADS, both with and without the FA feature, was evaluated based on accuracy, sensitivity, specificity, positive predictive value, and negative predictive value. RESULTS: The FA feature was found to be more prevalent in HCC (85.54%, p < 0.001) than in regenerative nodules (RNs, 29.73%), low-grade dysplastic nodules (LGDNs, 33.33%), and high-grade dysplastic nodules (HGDNs, 55.26%). Furthermore, the presence of arterial phase hyperenhancement (APHE), washout (WO), and FA in liver nodules was associated with a higher expression of GPC-3 and Ki-67 compared to the group without these features (p < 0.001). After adjusting, the sensitivity and accuracy of LR-5 for HCC improved from 68.67% (95%CI: 62.46%, 74.30%) to 77.51% (95%CI: 71.72%, 82.44%) and from 69.23% (95%CI: 64.11%, 74.02%) to 73.79% (95%CI: 68.86%, 78.31%), respectively. CONCLUSION: The FA feature is a valuable feature for distinguishing small HCC and precancerous lesions and could be added as a possible ancillary feature in CEUS LI-RADS which was backed up by biomarkers. CLINICAL RELEVANCE STATEMENT: The presence of a feeding artery is a valuable imaging feature in the differentiation of HCC and precancerous lesions. Incorporating this characteristic in the CEUS LI-RADS can enhance the diagnostic ability. KEY POINTS: • Feeding artery is more frequent in HCC than in regenerative nodules, low-grade dysplastic nodules, and high-grade dysplastic nodules. • Feeding artery feature is a valuable ancillary feature for CEUS LI-RADS to differentiate regenerative nodules, low-grade dysplastic nodules, high-grade dysplastic nodules, and HCC. • The existence of feeding artery, arterial phase hyperenhancement, and washout is associated with more GPC-3 positive expression and higher Ki-67 expression than the group without these features.

Sudden unexpected death of a young adult due to subarachnoid hemorrhage associated with polyarteritis nodosa: Clinicopathological appearance and literature review.

A 28-year-old male was found dead in his bedroom. There were no anomalies in his birth and medical history, and there was no family history of sudden unexpected death (SUD). Autopsy showed subarachnoid hemorrhage (SAH) with basilar top inflammatory pseudoaneurysm rupture accompanied by fibrinoid necrosis in the aneurysm wall. Active and healed arteritides in small- to medium-sized arteries were identified in the brain, heart, and systemic connective tissue, which was consistent with polyarteritis nodosa (PAN). Furthermore, pneumatosis cystoides intestinalis was observed in the ascending colon. Hepatitis B virus infection and antineutrophil nuclear antibodies were negative. Genetic investigation using whole-exome sequencing showed no mutations among autoinflammatory-related genes, including UBA1, MEFV, and ADA2. SAH due to rupture of a pseudoaneurysm formed by PAN was considered as the cause of death in the present case. Although myocardial ischemia linked to coronary arteritis is a recognized trigger for SUD in PAN, our study showed that rupture of inflammatory pseudoaneurysm in the cerebral artery can also cause SUD in younger subjects with PAN, even if prodromal symptoms are not evident before death.

Temporal lobe uncal herniation with contralateral superior cerebellar artery infarct.

Herniation of the temporal lobe uncus typically leads to the compression of the ipsilateral oculomotor nerve, resulting in ipsilateral mydriasis, as well as compression of the ipsilateral posterior cerebral artery, leading to infarction in the posterior inferior temporal lobe and medial occipital cortex. In this report, we present the case of a 45-year-old man with a large left subdural hematoma. At autopsy, we observed left cingulate and uncal herniations, along with the characteristic lesions of Kernohan notch phenomenon due to compression of the contralateral cerebral peduncle. Additionally, a hemorrhagic infarct was identified in the right cerebellar hemisphere in the distribution of the superior cerebellar artery (SCA). This case provides the first autopsy report of uncal herniation with contralateral SCA infarct, an extremely rare condition. Importantly, this vascular complication may often go unnoticed in patients with Kernohan notch phenomenon although it may carry a grave clinical prognosis.

Anatomical Variations and Anomalies of the Anterior Communicating Artery Complex.

BACKGROUND: Intracranial arteries have a high rate of variation, but a clear schematic overview is lacking. In this pictorial review we classify and depict all variations and anomalies within the anterior communicating artery complex. METHODS: PubMed was searched with the terms "Anterior Communicating Artery" AND "Variations" OR "Anomalies." Articles were selected based on their description of variants. Cross-referencing was used to broaden the range of variations. Surgical view during pterional craniotomy and transsylvian approach was used as a baseline for schematic drawings of the variations. RESULTS: A total of 42 variants were identified, schematically drawn and classified into A1-A2 segment, anterior communicating artery, and the recurrent artery of Heubner. CONCLUSIONS: The anterior communicating artery complex consists of the anterior cerebral artery, anterior communicating artery and the recurrent artery of Heubner. An overview of these variations may be helpful in distinguishing pathology from anatomical variations, assist neurosurgeons during clipping of cerebral aneurysms, and support interventional radiologists during endovascular treatments. This article summarizes the current knowledge of anatomical variations within the anterior communicating artery complex, their prevalence and clinical relevance. A total of 42 variants were identified and schematically depicted. We encourage all who diagnose, treat, and study the anterior communicating artery complex to use this overview for a uniform and better understanding of its anatomy.

Debris generated by laser and/or balloon cause cerebral infarction with different severity.

The purpose of this study is to determine the effects that debris generated by laser and/or balloon on the brain. Debris generated by laser, balloon, and laser combined with balloon were collected and then injected into rats' left common carotid artery. Rats were divided into five groups: sham, saline, laser (L), balloon (B), and laser combined with balloon (LB). The cognition ability of rats was evaluated by Morris water maze. Cerebral blood flow (CBF) was examined by laser speckle. TTC staining and MRI scan were conducted to detect cerebral ischemic infarction. Intracranial arteries in rats were visualized by MRI angiography via contrast medium injected via tail vein. Immunohistologic staining for NeuN and Iba1 and hematoxylin-eosin staining were performed to assess brain infarction. White matter demyelination was assessed by Luxol fast blue staining. Long-term memory and CBF of rats in different groups exhibited no significant difference. No obstruction sign in intracranial artery tree was noticed in each group. Debris generated by different treatments all caused brain infarction. Infarction lesion caused by debris produced by balloon was much more severe than the one caused by debris generated by laser. While the LB group lay in between. The thickness of white matter decreased in the B group, but not in the L and LB groups. Rat brain has a tolerance for debris as cognition ability and cerebral blood flow are not significantly declined. The severity of cerebral infarction varies by debris generated by different treatments.

Use of high-plex data provides novel insights into the temporal artery processes of giant cell arteritis.

Objective: To identify the key coding genes underlying the biomarkers and pathways associated with giant cell arteritis (GCA), we performed an in situ spatial profiling of molecules involved in the temporal arteries of GCA patients and controls. Furthermore, we performed pharmacogenomic network analysis to identify potential treatment targets. Methods: Using human formalin-fixed paraffin-embedded temporal artery biopsy samples (GCA, n = 9; controls, n = 7), we performed a whole transcriptome analysis using the NanoString GeoMx Digital Spatial Profiler. In total, 59 regions of interest were selected in the intima, media, adventitia, and perivascular adipose tissue (PVAT). Differentially expressed genes (DEGs) (fold-change > 2 or < -2, p-adjusted < 0.01) were compared across each layer to build a spatial and pharmacogenomic network and to explore the pathophysiological mechanisms of GCA. Results: Most of the transcriptome (12,076 genes) was upregulated in GCA arteries, compared to control arteries. Among the screened genes, 282, 227, 40, and 5 DEGs were identified in the intima, media, adventitia, and PVAT, respectively. Genes involved in the immune process and vascular remodeling were upregulated within GCA temporal arteries but differed across the arterial layers. The immune-related functions and vascular remodeling were limited to the intima and media. Conclusion: This study is the first to perform an in situ spatial profiling characterization of the molecules involved in GCA. The pharmacogenomic network analysis identified potential target genes for approved and novel immunotherapies.

Hemodynamic imaging parameters in brain metastases patients - Agreement between multi-delay ASL and hypercapnic BOLD.

Arterial spin labeling (ASL) MRI is a routine clinical imaging technique that provides quantitative cerebral blood flow (CBF) information. A related technique is blood oxygenation level-dependent (BOLD) MRI during hypercapnia, which can assess cerebrovascular reactivity (CVR). ASL is weighted towards arteries, whereas BOLD is weighted towards veins. Their associated parameters in heterogeneous tissue types or under different hemodynamic conditions remains unclear. Baseline multi-delay ASL MRI and BOLD MRI during hypercapnia were performed in fourteen patients with brain metastases. In the ROI analysis, the CBF and CVR values were positively correlated in regions showing sufficient reserve capacity (i.e. non-steal regions, rrm = 0.792). Additionally, longer hemodynamic lag times were related to lower baseline CBF (rrm = -0.822) and longer arterial arrival time (AAT; rrm = 0.712). In contrast, in regions exhibiting vascular steal an inverse relationship was found with higher baseline CBF related to more negative CVR (rrm = -0.273). These associations were confirmed in voxelwise analyses. The relationship between CBF, AAT and CVR measures seems to be dependent on the vascular status of the underlying tissue. Healthy tissue relationships do not hold in tissues experiencing impaired or exhausted autoregulation. CVR metrics can possibly identify at-risk areas before perfusion deficiencies become visible on ASL MRI, specifically within vascular steal regions.

Ten-year follow-up study of a young woman with loeys-dietz syndrome: a case report.

We herein report the 10-year surgical course of a 27-year-old woman who underwent two surgeries after being diagnosed with Loeys-Dietz syndrome. As described in previous cases, this patient developed ectopic arterial enlargement. We followed her temporal changes over a 10-year period, including the changes in computed tomography, pathology, and surgery.

X chromosome inactivation skewing is common in advanced carotid atherosclerotic lesions in females and predicts secondary peripheral artery events.

BACKGROUND AND AIM: Sex differences in atherosclerosis have been described with female plaques being mostly perceived as stable and fibrous. Sex-specific mechanisms such as mosaic loss of the Y chromosome in men have been linked to cardiovascular health. In women, X-linked mechanisms such as X chromosome inactivation (XCI) skewing is common in several tissues. Yet, information on the role of XCI in female atherosclerotic plaques is lacking. Here, we investigated the presence of XCI skewing in advanced atherosclerotic lesions and its association with cardiovascular risk factors, histological plaque data, and clinical data. METHODS: XCI skewing was quantified in 154 atherosclerotic plaque and 55 blood DNA samples of women included in the Athero-Express study. The skewing status was determined performing the HUMARA assay. Then, we studied the relationship of XCI skewing in female plaque and cardiovascular risk factors using regression models. In addition, we studied if plaque XCI predicted plaque composition, and adverse events during 3-years follow-up using Cox proportional hazard models. RESULTS: XCI skewing was detected in 76 of 154 (49.4%) plaques and in 27 of 55 (67%) blood samples. None of the clinical risk factors were associated with plaque skewing. Plaque skewing was more often detected in plaques with a plaque hemorrhage (OR [95% CI]: 1.44 [1.06-1.98], P = 0.02). Moreover, skewed plaques were not associated with a higher incidence of composite and major events but were specifically associated with peripheral artery events during a 3-year follow-up period in a multivariate model (HR [95%CI]: 1.46 [1.09-1.97]; P = 0.007). CONCLUSIONS: XCI skewing is common in carotid plaques of females and is predictive for the occurrence of peripheral artery events within 3 years after carotid endarterectomy.

Sex-differences have been observed in the development of atherosclerosis between men and women. Women tend to have more stable and fibrous plaques compared to men. Sex-specific mechanisms such as mosaic loss of the Y chromosome in men, were associated with cardiovascular health. In women, despite X-linked mechanisms like X chromosome inactivation (XCI) skewing was identified in various tissues. However, its relationship with atherosclerosis has not yet been investigated. In our study, we explored if prevalence of XCI skewing in advanced atherosclerotic lesions related to cardiovascular risk factors, histological plaque data, and clinical information. We found that XCI skewing was present in approximately 50% of human plaques, particularly those with plaque hemorrhage. Interestingly, we did not find any notable relationship between plaque skewing and clinical risk factors. However, we found that XCI was more present in women with peripheral artery events during the 3 years period following carotid endarterectomy. In summary, our findings indicate that XCI skewing is commonly observed in carotid plaques among females and may serve as a predictive factor for the occurrence of peripheral artery events within 3 years after carotid endarterectomy.

Magnetic Resonance Angiography of the Arteries of the Upper and Lower Extremities.

Magnetic resonance angiography (MRA) is a powerful tool for assessing upper and lower extremity artery pathologies. In addition to the classic advantages of MRA, such as the absence of radiation and iodinated contrast exposure, it can provide high temporal resolution/dynamic images of the arteries with high soft tissue contrast. Although it has a relatively lower spatial resolution than computed tomography angiography, MRA does not cause blooming artifacts in heavily calcified vessels, which is crucial in small vessel assessment. Although contrast-enhanced MRA is the most preferred technique to assess extremity vascular pathologies, recent advances in non-contrast MRA protocols provide an alternative imaging technique for patients with chronic kidney disease.

High-resolution magnetic resonance imaging of acute intracranial artery thrombus.

BACKGROUND AND PURPOSE: The development of high-resolution magnetic resonance imaging (HR-MRI) has enabled submillimeter-level evaluation of intracranial artery plaque and luminal thrombus. We sought to investigate the value of HR-MRI in assessing the pathogenesis of acute intracranial artery thrombus. METHODS: We examined the presence of intracranial thrombus on three-dimensional T1-weighted HR-MRI in acute ischemic stroke patients with intracranial artery occlusion on magnetic resonance angiography. We defined two thrombus-related HR-MRI features (peri-thrombus plaque and distal residual flow beyond the thrombus) and analyzed their association with potential embolic sources. RESULTS: Luminal thrombus and a shrunken artery without luminal thrombus were detected in 162 (96.4%) and six (3.6%) of 168 patients with intracranial artery occlusion, respectively. Among 111 patients with culprit major artery thrombus, peri-thrombus plaques were observed in 46.8% and distal residual flow beyond the thrombus in 64.0%. Patients with peri-thrombus plaque had a higher prevalence of diabetes (44.2% vs. 25.4%; p = 0.037), a lower prevalence of potential sources of cardioembolism (0% vs. 16.9%; p = 0.002), and a nonsignificantly lower prevalence of potential embolic sources from extracranial arteries (9.6% vs. 20.3%; p = 0.186) than those without. Patients with distal residual flow beyond the thrombus had a lower prevalence of potential sources of cardioembolism (1.4% vs. 22.5%; p < 0.001) and smaller infarct volumes (5.0 [1.4-12.7] mL vs. 16.6 [2.4-94.6] mL; p = 0.012) than those without. CONCLUSIONS: Our study showed that HR-MRI helps clarify the pathogenesis of acute intracranial artery thrombus. The presence of peri-thrombus plaque and distal residual flow beyond the thrombus favor the stroke mechanism of atherosclerosis rather than cardioembolism.