Plaque distribution of low-grade basilar artery atherosclerosis and its clinical relevance

Risk prediction of CISS classification in endovascular treatment of basilar artery stenosis

Objective

To investigate the incidence of ischemic stroke complications after endovascular treatment for basilar artery stenosis used preoperative high-resolution magnetic resonance vascular wall imaging (HRMR/VWI) and diffusion-weighted imaging (DWI).

Methods

The clinical data of 47 patients with severe symptomatic basilar artery stenosis (stenosis rate ≥70 %) treated with endovascular therapy at the Neuro-interventional Center from December 2017 to December 2021 were retrospectively analyzed. High-resolution magnetic resonance angiography (HRMR VWI) and DWI were used to evaluate the location of atherosclerotic plaque at basilar artery stenosis and the distribution of cerebral infarction lesions in all patients before surgery.According to the CISS classification system for ischemic stroke, patients were divided into a perforation group and a hypoperfusion group, and the general situation, plaque distribution, and incidence of ischemic stroke complications 7 days after endovascular treatment in the two groups were analyzed.

Results

There was no significant difference in baseline data between the two groups. After 7 days of intravascular treatment, the incidence of ischemic stroke was higher in the perforation group (20.0 %) than in the hypoperfusion group (0.0 %), and the difference was statistically significant (P = 0.027). A significant association was found between the perforation group and the hypoperfusion group for the incidence of ischemic stroke at 7 days (P = 0.003, OR = 2.347; 95 % CI = 2.056-4.268). There were a higher proportion of ventral plaques (74.1 %) and a lower proportion of dorsal plaques (33.3 %) in the hypoperfusion group, which were 15.0 % and 90.0 % in the perforation group, respectively (χ2 = 16.045, P < 0.001; χ2 = 15.092, P < 0.001). There was no significant difference in the proportion of left and right plaques between the two groups.

Conclusions

The risk of ischemic stroke is greater in patients with perforator artery obstruction undergoing endovascular therapy, and lower in patients with hypoperfusion/embolus removal.

Effect of dominant vertebral artery angle on basilar artery curvature and plaque

Background

Quantification of vertebral arteries can provide insights into basilar curvature and plaque. Therefore, this retrospective study aimed at identifying the dominant vertebral artery (VA) causing basilar artery (BA) curvature and to further quantify the effect of dominant VA angle on BA curvature and BA plaque using high-resolution magnetic resonance imaging (HRMRI) and 3-dimensional time-of-flight magnetic resonance angiography (3D-TOF-MRA).

Methods

This retrospective analysis included 521 participants who underwent HRMRI in the China-Japan Friendship Hospital from November 2015 to October 2021 for neurological symptoms or signs. The VA angle more related to BA curvature was defined as the dominant VA angle. Multivariable linear regression analysis was used to evaluate the relationship between the dominant VA angle and mid-BA angle, while multivariable logistics regression was used to evaluate the influence of the dominant VA angle and clinical risk factors on BA plaque.

Results

In total, 259 participants were included in this study (mean age 53.71±13.12 years; 146 males). The balanced-type participants had a significantly lower probability of BA plaques (P<0.001). The Chi-squared test showed that the BA curvature direction was significantly associated with the side with larger VA diameter (P<0.001) and larger VA angle (P<0.001). As a result, the VA angle on the side with the larger diameter or the larger VA angle when the diameters were similar was considered to be the dominant VA angle. The dominant VA angle was independently correlated with the mid-BA angle (P<0.001). In addition, the dominant VA angle was also an independent risk factor for BA plaque. Additionally, 80° was the cutoff value of the dominant VA angle, and when the dominant VA angle was greater than 80°, the risk of BA plaque increased about 18-fold [odds ratio, 18.951; 95% confidence interval (CI): 4.545-79.026; P<0.001].

Conclusions

The dominant VA angle was independently associated with BA plaque, and a dominant VA angle greater than 80° may be a marker for a high risk of posterior circulation atherosclerosis.

Clinical Relevance of Plaque Distribution for Basilar Artery Stenosis

BACKGROUND AND PURPOSE

There is no clear association between plaque distribution and postoperative complications in patients with basilar artery atherosclerotic stenosis. The aim of this study was to determine whether plaque distribution and postoperative complications after endovascular treatment for basilar artery stenosis are related.

MATERIALS AND METHODS

Our study enrolled patients with severe basilar artery stenosis who were scanned with high-resolution MR imaging and followed by DSA before the intervention. According to high-resolution MR imaging, plaques can be classified as ventral, lateral, dorsal, or involved in 2 quadrants. Plaques affecting the proximal, distal, or junctional segments of the basilar artery were classified according to DSA. An experienced independent team assessed ischemic events after the intervention using MR imaging. Further analysis was conducted to determine the relationship between plaque distribution and postoperative complications.

RESULTS

A total of 140 eligible patients were included in the study, with a postoperative complication rate of 11.4%. These patients were an average age of 61.9 (SD, 7.7) years. Dorsal wall plaques accounted for 34.3% of all plaques, and plaques distal to the anterior-inferior cerebellar artery accounted for 60.7%. Postoperative complications of endovascular treatment were associated with plaques located at the lateral wall (OR = 4.00; 95% CI, 1.21-13.23; P = .023), junctional segment (OR = 8.75; 95% CI, 1.16-66.22; P = .036), and plaque burden (OR = 1.03; 95% CI, 1.01-1.06; P = .042).

CONCLUSIONS

Plaques with a large burden located at the junctional segment and lateral wall of the basilar artery may increase the likelihood of postoperative complications following endovascular therapy. A larger sample size is needed for future studies.

Association between basilar artery stenosis features, vertebral artery stenosis and perforator stroke after stenting

BACKGROUND AND PURPOSE

We investigated the relationship between basilar artery (BA) atherosclerotic stenosis features and vertebral artery (VA) stenosis and explored whether BA stenosis features are associated with perforator stroke after stenting.

METHODS

Patients with BA stenosis who underwent HRMRI and DSA were recruited. Patients were divided into proximal BA stenosis and middle-or-distal BA stenosis groups, and then subgroup analyses were performed based on whether they had VA stenosis. BA plaque features were evaluated by HRMRI. Artery stenosis was measured by DSA. The incidence of perforator stroke after BA stenting was recorded, and the potential association between BA stenosis features and perforator stroke was analyzed.

RESULTS

One hundred and seventy-four patients were consecutively enrolled. Patients with proximal BA stenosis had a higher proportion of severe stenosis than those with middle-or-distal BA stenosis (P = 0.027). In the subgroup analysis, this difference mainly existed in patients complicated with VA stenosis (P = 0.023). Patients with proximal BA stenosis had a higher proportion of strong plaque enhancement than those with middle-or-distal BA stenosis (P < 0.001), especially in those with vertebrobasilar junction (VBJ) stenosis (P < 0.001). Perforator stroke after BA stenting occurred in five patients, of whom four had lateral wall BA plaques, four had plaque enhancement and four had proximal BA stenosis.

CONCLUSION

Patients with proximal BA stenosis had a higher proportion of severe stenosis and strong plaque enhancement, particularly in patients complicated with VA stenosis and VBJ stenosis. Perforator stroke after BA stenting may be related to distribution, burden and characteristics of BA lesions.

Basilar artery plaque distribution is associated with pontine infarction and vertebrobasilar artery geometry

Background

Basilar artery (BA) atherosclerosis is a common cause of posterior-circulation ischemic stroke. In this study, we investigate the relationship between BA plaque distribution and pontine infarction (PI), further, explore the influence of vertebrobasilar artery (VBA) geometries on BA plaque distribution.

Materials and methods

303 patients were performed with MRI in this study, patients were divided into three groups: no cerebral infarction (NCI), anterior circulation cerebral infarction (ACCI), and posterior circulation cerebral infarction (PCCI), the VBA geometry was classified into four configurations: Walking, Tuning Fork, Lambda, and No Confluence. The AP-Mid-BA, Lateral-Mid-BA, and VA-BA angles were measured on three-dimensional time-of-flight magnetic resonance angiography. Patients underwent high-resolution magnetic resonance imaging to evaluate the BA plaque distribution (either anterior, posterior, or lateral wall). Acute and subacute cerebral infarction [including pontine infarction (PI)] were identified by T2 weighted imaging-fluid-attenuated inversion recovery and diffusion-weighted imaging.

Results

The presence of BA plaque (P &lt; 0.001) were associated with PCCI. Eighty-six patients all with BA plaque were further analyzed, compared with patients without pontine infarction, patients with pontine infarction were more likely to have plaque distributed at the posterior wall (P = 0.009) and have larger VA-BA anger (38.72° ± 26.01° vs. 26.59° ± 17.33°, P = 0.035). BA plaques in patients with pontine infarction were more frequently located at the posterior wall (50.00%) than at the anterior (10.00%) and lateral (37.50%) walls (P = 0.028). In Walking, Lambda and No Confluence geometry, BA plaques were prone to located at the lateral wall than at the anterior and posterior walls (all P ≤ 0.05). In the Tuning Fork group, BA plaques were evenly distributed.

Conclusion

BA plaque was related to PCCI, BA plaque distribution was associated with PI, and VBA configuration strongly influences BA plaque distribution.

Effect of Mid-Basilar Artery Angle and Plaque Characteristics on Pontine Infarction in Patients with Basilar Artery Plaque

AIMS

The basilar artery (BA) geometry and plaque characteristics may play an important role in the development of atherosclerosis. This study was performed to explore the relationship between the mid-BA angle and plaque characteristics and its effect on pontine infarction using high-resolution magnetic resonance imaging and three-dimensional time-of-flight magnetic resonance angiography.

METHODS

In total, 77 patients with BA plaques were included in this study. According to the presence of acute pontine infarction on diffusion-weighted imaging, the patients were divided into a pontine infarction group and pontine non-infarction group. The mid-BA angle, plaque burden, stenosis ratio, positive remodeling, and intraplaque hemorrhage were evaluated to investigate their effects on stroke.

RESULTS

The pontine infarction group had a greater plaque burden, stenosis ratio, positive remodeling, and mid-BA angle than the pontine non-infarction group. The correlation between the plaque burden and mid-BA angle was the highest (r=0.441, P＜0.001). Multivariate logistic regression analysis showed that the plaque burden (odds ratio, 1.164; 95% confidence interval, 1.093-1.241; P＜0.001) was an independent risk factor for pontine infarction.

CONCLUSION

The mid-BA angle may increase the incidence of pontine infarction by increasing the plaque burden.

Relationship Between Hypertension and Basilar Atherosclerosis in Chinese Han Population: A High-Resolution Magnetic Resonance Imaging Study

Objective

To investigate the relationship between hypertension and basilar atherosclerosis evaluated by high-resolution magnetic resonance imaging (HR-MRI) in the Chinese Han population.

Methods

High resolution-MRI vessel wall imaging was performed in selected 193 patients for various indications. Multivariable logistic regression models based on odds ratio (OR) with their associated 95% confidence interval (CI) were used to assess the relationship between hypertension and basilar artery (BA) plaque, moderate or severe stenosis of BA plaque, and vulnerable plaque. A linear regression model was used to assess the relationship between hypertension and BA plaque numbers.

Results

Patients with hypertension had a higher proportion of BA plaque and vulnerable plaque as well as more number of enhancements of BA plaque and serious plaque compared with normotensive patients (all values of p < 0.05). Multivariable logistic regression analysis indicated that patients with hypertension had an increased risk for and more number of enhancements of BA plaque (adjusted-OR: 4.32, 95% CI 1.89–9.88, p < 0.001; adjusted-β: 0.55, 95% CI 0.14–0.96, p = 0.009, respectively) and had a higher proportion of moderate or severe stenosis of BA plaque and vulnerable plaque (adjusted-OR: 3.08, 95% CI 0.77–12.32, p = 0.111; adjusted-OR: 4.52, 95% CI 1.50–13.64, p = 0.007, respectively) compared with the normotensive group. Moreover, there was a saturation effect of age on the prevalence of BA plaque and vulnerable plaque.

Conclusion

Hypertension was the independent risk factor of BA plaque and vulnerable plaque assessed by HR-MRI in the Chinese Han population.

A Predictive Model for the Risk of Posterior Circulation Stroke in Patients with Intracranial Atherosclerosis Based on High Resolution MRI

Intracranial vertebrobasilar atherosclerosis is the main cause of posterior circulation ischemic stroke. We aimed to construct a predictive model for the risk of posterior circulation ischemic stroke in patients with posterior circulation atherosclerosis based on high-resolution MRI (HR-MRI). A total of 208 consecutive patients with posterior circulation atherosclerosis confirmed by HR-MRI, from January 2020 to July 2021, were retrospectively assessed. They were assigned to the posterior circulation stroke (49 patients) and non-posterior circulation stroke group (159 patients) based on clinical presentation and diffusion-weighted imaging (DWI). Demographic data, risk factors of atherosclerosis, laboratory findings, and imaging characteristics were extracted from electronic health records. Plaque features were investigated by HR-MRI. Fifty-three clinical or imaging features were used to derive the model. Multivariable logistic regression analysis was employed to construct the prediction model. The nomogram was evaluated for calibration, differentiation, and clinical usefulness. Plaque enhancement, plaque irregular surface morphology, artery location of plaque, and dorsal quadrant of plaque location were significant predictors for posterior circulation stroke in patients with intracranial atherosclerosis. Subsequently, these variables were selected to establish a nomogram. The model showed good distinction (C-index 0.830, 95% CI 0.766-0.895). The calibration curve also showed excellent consistency between the prediction of the nomogram and the observed curve. Decision curve analysis further demonstrated that the nomogram conferred significantly high clinical net benefit. The nomogram calculated from plaque characteristics in HR-MRI may accurately predict the posterior circulation stroke occurrence and be of great help for stratification of stroke decision making.

The Longitudinal Distribution and Stability of Curved Basilar Artery Plaque: A Study Based on HR-MRI

AIMS

This study aims to evaluate the differences in the characteristics of atherosclerotic plaques in the proximal, curved, and distal segments of the curved basilar artery (BA) through high-resolution magnetic resonance imaging(HR-MRI).

METHODS

The imaging and clinical data of 146 patients were retrospectively analyzed. On the basis of three-dimensional (3D) time -of -flight magnetic resonance angiography (3D-TOF-MRA), 51 patients with BA curvature were selected for the study. The BA plaque is divided into three groups: proximal, curved, and distal. Plaques were identified and analyzed according to spin echo acquisition imaging via T1-weighted 3D volumetric isotropic Tse acquisition (T1W-3D -VISTA), and compare the differences in clinical related factors and plaque characteristics between groups. Diffusion-weighted imaging (DWI) and/or T2WI identified brainstem infarction. The patients were divided into symptomatic and asymptomatic groups. The correlation between plaque location and symptoms was identified and analyzed.

RESULTS

Among 51 patients, a total of 376 plaques were detected. Plaques in the proximal and curved segments are more common than those in the distal segments. Proximal plaques are more likely to have intraplaque hemorrhage ( P=0.002 ＜0.05). There was no significant difference in the distribution of criminal plaques and non-criminal plaques between each group (P=0.36 ＞0.05).

CONCLUSION

Plaques in the proximal and curved segments of the BA are more common than those in the distal segments. The proximal plaque is more prone to intraplaque hemorrhage.

Intraplaque Enhancement Is Associated With Artery-to-Artery Embolism in Symptomatic Vertebrobasilar Atherosclerotic Diseases

Objective: There are limited data regarding the characteristics of intracranial plaques according to stroke mechanism in the posterior circulation. This study aims to compare whether the plaque characteristics and baseline features are different in patients with artery-to-artery (A-to-A) embolism and those with parent artery disease in the intracranial vertebrobasilar atherosclerotic disease.

Methods: From September 2014 to January 2017, patients with recent posterior circulation stroke due to intracranial vertebrobasilar atherosclerotic disease were retrospectively analyzed. Patients with the following eligibility criteria were included: (1) age ≥18 years old, (2) ischemic stroke in the vertebrobasilar territory, (3) 70–99% stenosis of the intracranial vertebral artery or basilar artery, and (4) two or more atherosclerotic risk factors. Patients with concomitant ipsilateral or bilateral extracranial vertebral artery >50% stenosis, cardio-embolism, or non-atherosclerotic stenosis were excluded. The plaque characteristics, including intraplaque compositions (intraplaque hemorrhage and intraplaque calcification), intraplaque enhancement, and remodeling index, were evaluated by using 3T high-resolution magnetic resonance imaging (HRMRI). The baseline features including vascular risk factors and the involved artery were collected. Patients were divided into A-to-A embolism and parent artery disease groups based on the diffusion-weighted images, T2-weighted images, or computed tomography. The plaque characteristics and baseline features were compared between the two groups.

Results: Among consecutive 298 patients, 51 patients were included. Twenty-nine patients had A-to-A embolism and 22 patients had parent artery disease. Compared with parent artery disease, the occurrence rates of intraplaque enhancement and intracranial vertebral involvement were higher in the A-to-A embolism group (79.3 vs. 36.4%; p = 0.002 and 62.1 vs. 18.2%; p = 0.002, respectively). Multivariable logistic regression analysis showed that intraplaque enhancement and intracranial vertebral artery plaques were also associated with A-to-A embolism (adjusted OR, 7.31; 95% CI 1.58–33.77; p = 0.011 and adjusted OR, 9.42; 95% CI 1.91–46.50; p = 0.006, respectively).

Conclusion: Intraplaque enhancement and intracranial vertebral artery plaques seem to be more closely associated with A-to-A embolism than parent artery disease in patients with symptomatic intracranial vertebrobasilar disease.

Clinical Trial Registration:http://www.clinicaltrials.gov, identifier: NCT02705599.

Gadolinium enhancement of atherosclerotic plaque in the intracranial artery

Background: Gadolinium enhancement on high resolution magnetic resonance imaging (HR-MRI) has been considered a sign of instability and inflammation of intracranial atherosclerotic plaques. Our research objective was to explore the relationship between the extent of plaque enhancement (PE), the degree of intracranial artery stenosis, and acute ischemic stroke events.Methods: HR-MRI was performed in 91 patients with intracranial vascular stenosis to determine the existence and intensity of PE.Results: Among 91 patients enrolled in the trial, there were 43 patients in the acute/subacute group (≤1 month from ischemic stroke event), 15 patients in the chronic group (>1 month from ischemic stroke event), and 33 patients in the non-culprit plaques group (no ischemic stroke event). A total of 105 intracranial atherosclerotic plaques were detected in 91 patients. 14 (13.3%) were mild-stenosis plaques, 22 (21.0%) were moderate-stenosis plaques, and 69 (65.7%) were severe-stenosis plaques. There were 12 (11.4%), 18 (17.1%), and 75 (71.4%) plaques in the non-enhanced plaque group, the mild-enhancement group, and the significant-enhancement group, respectively. The degree of PE among the acute/subacute group, the chronic group, and the non-culprit plaque group had a significant difference (P = 0.005). Enhanced plaques were more often observed in culprit plaques (acute/subacute group and chronic group) than non-culprit plaques (96.7% vs 77.3%). Non-enhanced plaques were more often observed in non-culprit plaques than culprit plaques (acute/subacute group and chronic group) (22.7% vs 3.3%). And 36.6% of the enhanced plaques were non-culprit plaques. After performing univariate and multivariate logistic regression analysis, the results showed that strong plaque enhancement (P = 0.025, odds ratio [OR] 3.700, 95% confidence interval [95% CI] 1.182-11.583) and severe stenosis (P = 0.008, OR 4.393, 95%CI 1.481-13.030) were significantly associated with acute ischemic events.Conclusion: Enhanced plaques were more often observed in culprit plaques, and non-enhanced plaques were more often observed in non-culprit plaques. Moreover, significant plaque enhancement and severe ICAS were closely associated with acute ischemic events.

Association between the vertebrobasilar artery geometry and basilar artery plaques determined by high-resolution magnetic resonance imaging

Background

Atherosclerotic plaques are often present in regions of arteries with complicated flow patterns. Vascular morphology plays important role in hemodynamics. In this study, we investigated the relationship between the geometry of the vertebrobasilar artery system and presence of basilar artery (BA) plaque.

Methods

We enrolled 290 patients with posterior circulation ischemic stroke. We distinguished four configurations of the vertebrobasilar artery: Walking, Tuning Fork, Lambda, and No Confluence. Patients were divided into multi-bending (≥ 3 bends) and oligo-bending (< 3 bends) VA groups. The diameter of the vertebral artery (VA) and the number of bends in the intracranial VA segment were assessed using three-dimensional time-of-flight magnetic resonance angiography. High-resolution magnetic resonance imaging was used to evaluate BA plaques. Logistic regression models were used to determine the relationship between the geometry type and BA plaque prevalence.

Results

After adjusting for sex, age, body mass index ≥ 28, hypertension, and diabetes mellitus, the Walking, Lambda, and No Confluence geometries were associated with the presence of BA plaque (all p < 0.05). Patients with multi-bending VAs in both the Walking (20/28, 71.43% vs. 6/21, 28.57%, p = 0.003) and Lambda group (19/47, 40.43% vs. 21/97, 21.65%, p = 0.018) had more plaques compared to patients with oligo-bending VAs in these groups. In the Lambda group, the difference in diameter of bilateral VAs was larger in patients with BA plaques than that in patients without BA plaques (1.4 mm [IQR: 0.9–1.6 mm] vs. 0.9 mm [IQR: 0.6–1.3 mm], p < 0.001).

Conclusions

The Walking, Lambda, and No Confluence geometry, ≥ 3 bends in the VAs, and a large diameter difference between bilateral VAs are associated with the presence of BA plaque.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12868-021-00624-5.

Risk Factors of New Cerebral Infarctions After Endovascular Treatment for Basilar Artery Stenosis Based on High-Resolution Magnetic Resonance Imaging

Objective: The current study aims to analyze the risk factors of new cerebral infarctions in the distribution of basilar artery (BA) detected by diffusion-weighted imaging (DWI) after endovascular treatment in patients with severe BA stenosis. Methods: Data was collected from the electronic medical records of patients with severely atherosclerotic basilar artery stenosis (≥70%) who underwent endovascular treatment. The plaque characteristics, including the plaque distribution, plaque burden, plaque enhancement index, remodeling ratio, and stenosis degree, were evaluated qualitatively and quantitatively using high-resolution magnetic resonance imaging (HR-MRI) and digital subtraction angiography (DSA). The characteristics of the procedure, such as the type of treatment, balloon diameter, balloon length, stent diameter, and stent length, were analyzed. Results: A total of 107 patients with severe basilar artery stenosis (≥70%) who underwent endovascular treatment were enrolled. The study participants included 77 men and 30 women, with an average age of 61.6 ± 8.1 years. The rate of postoperative new cerebral infarctions was 55.1% (59/107), of which 74.6% (44/59) were caused by artery-to-artery embolism, 6.8% (4/59) due to perforator occlusion, and 18.6% (11/59) were caused by a mixed mechanism. Twelve of 59 patients had ischemic events, with nine cases of stroke and three cases of transient ischemic attacks (TIA). The plaque burden in the DWI-positive group was significantly larger than that in the DWI-negative group (3.7% vs. -8.5%, p = 0.016). Positive remodeling was more common in the DWI-positive group than in the DWI-negative group (35.6% vs. 16.7%, p = 0.028). Smoking was inversely correlated with the rate of new cerebral infarctions (odds ratio, 0.394; 95% confidence interval, 0.167-0.926; p = 0.033). Conclusion: The plaque characteristics are not associated with new cerebral infarctions in the distribution of BA, although a large plaque burden and positive remodeling are more likely to appear in patients with new cerebral infarctions after BA stenting, which warrants further studies with a larger sample size. As for smoking, the inverse correlation with new cerebral infarctions in the BA territory needs large-scale prospective randomized controlled trials to verify.

Imaging endpoints of intracranial atherosclerosis using vessel wall MR imaging: a systematic review

PURPOSE

The vessel wall MR imaging (VWI) literature was systematically reviewed to assess the criteria and measurement methods of VWI-related imaging endpoints for symptomatic intracranial plaque in patients with ischemic events.

METHODS

PubMed, Scopus, Web of Science, EMBASE, and Cochrane databases were searched up to October 2019. Two independent reviewers extracted data from 47 studies. A modified Guideline for Reporting Reliability and Agreement Studies was used to assess completeness of reporting.

RESULTS

The specific VWI-pulse sequence used to identify plaque was reported in 51% of studies. A VWI-based criterion to define plaque was reported in 38% of studies. A definition for culprit plaque was reported in 40% of studies. Frequently scored qualitative imaging endpoints were plaque quadrant (21%) and enhancement (21%). Frequently measured quantitative imaging endpoints were stenosis (19%), lumen area (15%), and remodeling index (14%). Reproducibility for all endpoints ranged from good to excellent (range: ICC_{T1 hyperintensity} = 0.451 to ICC_stenosis = 0.983). However, rater specialty and years of experience varied among studies.

CONCLUSIONS

Investigators are using different criteria to identify and measure VWI-imaging endpoints for culprit intracranial plaque. Early awareness of these differences to address methods of acquisition and measurement will help focus research resources and efforts in technique optimization and measurement reproducibility. Consensual definitions to detect plaque will be important to develop automatic lesion detection tools particularly in the era of radiomics.

[A case of definite diagnosis of branch atheromatous disease confirmed by digital subtraction angiography-3 tesla magnetic resonance fusion imaging]

We herein experienced one patient with typical branch atheromatous disease (BAD) type infarction. Digital subtraction angiography (DSA) and MRI fusion imaging revealed the relationship between atheromatous plaque and perforating branches. A 66-year-old male presented acute onset of dysarthria, the left side hemiparesis and sensory disturbance. Diffusion-weighted MR imaging (DWI) showed the right pontine acute infarction. We started to treat with dual antiplatelet therapy. However, the left-side hemiparesis was worsening on 4 days after admission. DWI showed infarct growth and plaque imaging revealed the atheromatous plaque in the basilar artery. We fused DSA and MRI T₂ weighted imaging (DSA-MR fusion imaging) to illustrate the relationship between the atheromatous plaque and the perforating branches. DSA-MR fusion imaging showed that the paramedian artery and the short circumferential artery ran around and into the pontine infarct lesion. Additionally, one of the paramedian arteries was occluded. Those neuroradiological findings coincided with the pathological concept of BAD. DSA-MR fusion imaging can prove the pathological concept of BAD.

A High-Resolution MRI Study of the Relationship Between Plaque Enhancement and Ischemic Stroke Events in Patients With Intracranial Atherosclerotic Stenosis

Purpose: To investigate the relationships among the degree of intracranial atherosclerotic stenosis (ICAS), plaque enhancement (PE), and ischemic stroke events (ISEs) using 3. 0 T high-resolution magnetic resonance imaging (HR-MRI). Materials and Methods: Fifty-two ICAS patients who underwent HR-MRI were retrospectively analyzed. The patients were divided into two groups according to the results of whole-brain digital subtraction angiography (DSA): the mild-moderate stenosis group (group MID) and the severe stenosis group (group SEV). According to the onset time of the ISEs, the plaques were divided into the acute/sub-acute phase culprit plaque group (group ACU, within 1 month), the chronic-phase culprit plaque group (group CHR, more than 1 month), and the non-culprit plaque group (group NON). Two neuroradiologists independently measured the signal intensity of PE and pituitary enhancement in the HR-MRI and calculated the ratio of the two indices. According to the ratio, the patients were divided into three groups: the marked enhancement group (group MA), the mild enhancement group (group ME), and the no enhancement plaque group (group NO). The relationships among the degree of ICAS, the degree of PE and ISEs were analyzed. Results: Seventy-two ICAS plaques were identified in 52 patients. The multiple independent samples Kruskal-Wallis H test showed that the differences among group ACU, CHR, and NON were significant in the degree of PE (P = 0.002). Group CHR and group NON were combined as the non-acute phase group (group non-ACU). Group NO and group ME were combined as the non-marked enhancement group (group non-MA). The comparison between group ACU and group non-ACU showed significant differences in the degree of both ICAS (P = 0.014) and PE (P = 0.006) according to the univariate logistic regression. The multivariate logistic regression model was used to analyze the impact of the degree of ICAS and PE on ISEs, and the results showed that severe stenosis (P = 0.036) and marked PE (P = 0.013) were independent risk factors for acute ISEs, respectively. Conclusion: Severe intracranial arterial stenosis and marked plaque enhancement are independent risk factors for acute ischemic stroke events, respectively. The study provides new ideas for further exploring the pathogenesis of stroke caused by intracranial atherosclerotic stenosis.

Interstudy reproducibility of dark blood high-resolution MRI in evaluating basilar atherosclerotic plaque at 3 Tesla

PURPOSE

We aimed to evaluate the interscan, intraobserver, and interobserver reproducibility of basilar atherosclerotic plaque employing dark blood high-resolution magnetic resonance imaging (HR-MRI) at 3 Tesla.

METHODS

Sixteen patients (14 males and 2 females) with > 30% basilar stenosis as identified by conventional magnetic resonance angiography were prospectively recruited for scan and rescan examinations on a 3 Tesla MRI system using T2-weighted turbo spin-echo protocol. Two observers independently measured the areas of vessels and lumens. Wall area was derived by subtracting the lumen area from the vessel area. Areas of vessels, lumens and walls were compared for the evaluation of interscan variability of basilar plaque. To assess the intraobserver variability, one observer reevaluated all the images of the first scan after a 4-week interval.

RESULTS

Fourteen patients were included in the final analysis. No clinically significant difference was observed for interscan, intraobserver, and interobserver measurements. The intraclass correlations for vessel, lumen, and wall areas were excellent and ranged from 0.973 to 0.981 for the interscan measurements, 0.997 to 0.998 for the intraobserver measurements and 0.979 to 0.985 for the interobserver measurements. The coefficients of variation for quantitative basilar morphology measurements were 4.31%-10.35% for the interscan measurements, 1.41%-4.62% for the intraobserver measurements and 3.79%-8.46% for the interobserver measurements. Compared with the interscan and interobserver measurements, narrow intervals of the scatterplots were observed for the intraobserver measurements by Bland-Altman plots.

CONCLUSION

Basilar atherosclerotic plaque imaging demonstrates excellent reproducibility at 3 Tesla. The study proves that dark blood HR-MRI may serve as a reliable tool for clinical studies focused on the progression and treatment response of basilar atherosclerosis.

Middle cerebral artery geometric features are associated with plaque distribution and stroke

OBJECTIVE

We aimed to investigate the geometric features of the middle cerebral artery (MCA) and their relevance to plaque distribution and ischemic stroke.

METHODS

We reviewed our institutional vessel wall imaging database. Patients with symptomatic MCA atherosclerosis, asymptomatic MCA atherosclerosis, or without MCA atherosclerosis were included. The MCA geometric features, including M1 segment shape and M1 curve orientation, were defined on magnetic resonance angiography. Plaque distribution and other plaque parameters were identified on vessel wall imaging. The association among MCA geometric features, plaque distribution, and ischemic stroke were analyzed.

RESULTS

A total of 977 MCAs were analyzed (87 atherosclerotic symptomatic MCAs, 459 atherosclerotic asymptomatic MCAs, and 431 plaque-free MCAs). Overall, curved M1 segments were the predominant shape across all groups. In 91.1% of curved atherosclerotic MCAs, the plaque involved the inner wall of the curve. Plaque not involving the inner wall was shorter (p < 0.0001) and thinner (p = 0.005) compared to plaque involving the inner wall. Inferior plaque was observed in 39.9% of inferior-oriented M1 curves compared to 21.7% in non-inferior-oriented M1 curves (p < 0.0001). The absence of an inferior-oriented M1 curve (odds ratio 0.45, 95% confidence interval 0.27-0.77) and presence of superior plaque (odds ratio 2.67, 95% confidence interval 1.52-4.67) were independently associated with stroke after adjusting for plaque length and thickness, degree of stenosis, and remodeling ratio.

CONCLUSIONS

MCA geometric features are associated with plaque distribution and stroke. Our findings provide insight into the vascular pathophysiology of MCA atherosclerosis.

Clinical Implications of Basilar Artery Plaques in the Pontine Infarction with Normal Basilar Angiogram: A High-Resolution Magnetic Resonance Imaging Study

BACKGROUND

Using high-resolution magnetic resonance imaging (HR-MRI), we investigated the impact of basilar artery plaques that were not detected by magnetic resonance angiography (MRA) on the functional outcomes of patients with acute pontine infarction.

METHODS

A total of 40 patients with acute pontine infarction and normal basilar findings on MRA prospectively underwent HR-MRI for detection of basilar artery plaques. A relevant plaque was defined as one on the dorsal side of basilar artery, the same side of the ischemic lesion, and the same axial slices of the ischemic lesion. We analyzed the relationship between the relevant basilar artery plaques and the functional outcomes at 3 months.

RESULTS

The initial National Institutes of Health Stroke Scale score (3.5 versus 2.0, P = .012), and the incidences of neurological deterioration (42.9% versus 6.3%, P = .031) and unfavorable functional outcome (71.4% versus 12.5%, P = .001) were higher in patients with relevant basilar artery plaques than in those without. On multiple regression analysis, the relevant basilar artery plaque was a significant and independent predictor of unfavorable functional outcome (odds ratio, 6.662; 95% confidence interval, 1.117-39.735; P = .037).

CONCLUSIONS

The presence of a relevant basilar artery plaque was closely related with unfavorable functional outcome in patients with acute pontine infarction even if the patients' MRA showed normal basilar findings.

Relationship between the geometry patterns of vertebrobasilar artery and atherosclerosis

Background

The plaques at the dorsal or lateral wall of basilar artery (BA) are associated with pontine infarcts. We sought to explore the correlations between vertebrobasilar artery geometry and BA plaque locations.

Methods

We retrospectively analyzed the imaging and clinical data of 84 patients with BA atherosclerosis. On three-dimensional time-of-flight images, a side to side diameter difference of bilateral vertebral artery (VA) and BA bending were assessed. The vertebrobasilar artery geometry was qualitatively classified into four basic configurations: Walking, Tuning Fork, Dominant-Lambda, and Hypoplasia-Lambda. On high-resolution magnetic resonance imaging, the plaques were categorized based on the involvement of the ventral, dorsal, or lateral sides of BA wall. The relationships between vertebrobasilar artery geometry parameters and plaque locations were analyzed.

Results

Left VA dominance was identified in 28(33%) patients, and right VA dominance in 22(26%) patients. BA bending were detected in 49 patients. There were no significant correlations between the diameter difference/ratio of VA diameters and plaque locations, or between BA bending and plaque locations. BA plaques were evenly distributed in the vertebrobasilar arteries with Tuning Fork and Dominant-Lambda configurations. In Hypoplasia-Lambda group, however, plaques were more frequently located at the dorsal wall (58.57%) than at the ventral (14.43%) and lateral wall (26.71%; P = 0.001). In Walking group, the plaques more likely occurred at the lateral (49.79%) and dorsal (35.07%) wall than at the ventral wall (14.86%, P = 0.02).

Conclusions

The geometric configurations of vertebrobasilar artery strongly influence the BA plaque locations. Further prospective studies are warranted to testify whether Hypoplasia-Lambda and Walking configurations are independent risk factors for pontine infarcts.

Electronic supplementary material

The online version of this article (10.1186/s12883-018-1084-6) contains supplementary material, which is available to authorized users.

MRI of plaque characteristics and relationship with downstream perfusion and cerebral infarction in patients with symptomatic middle cerebral artery stenosis

BACKGROUND

Intracranial plaque characteristics are associated with stroke events. Differences in plaque features may explain the disconnect between stenosis severity and the presence of ischemic stroke.

PURPOSE

To investigate the relationship between plaque characteristics and downstream perfusion changes, and their contribution to the occurrence of cerebral infarction beyond luminal stenosis.

STUDY TYPE

Case control.

SUBJECTS

Forty-six patients with symptomatic middle cerebral artery (MCA) stenosis (with acute cerebral infarction, n = 30; without acute cerebral infarction, n = 16).

FIELD STRENGTH/SEQUENCE

3.0T with 3D turbo spin echo sequence (3D-SPACE).

ASSESSMENT

Luminal stenosis grade, plaque features including lesion T₂ and T₁ hyperintense components, plaque enhancement grade, and plaque distribution were assessed. Brain perfusion was evaluated on mean transient time maps based on the Alberta Stroke Program Early CT score (MTT-ASPECTS).

STATISTICAL TESTS

Plaque features, grade of luminal stenosis, and MTT-ASPECTS were compared between two groups. The association between plaque features and MTT-ASPECTS were assessed using Spearman's correlation analysis. Multivariate logistic regression and receiver operating characteristic (ROC) curves were constructed to assess the effect of significant variables alone and their combination in determining the occurrence of cerebral infarction.

RESULTS

Stronger enhanced plaques were associated with downstream lower MTT-ASPECTS (P = 0.010). Plaque enhancement grade (P = 0.039, odds ratio [OR] 5.9, 95% confidence interval [CI] 1.1-32) and MTT-ASPECTS (P = 0.003, OR 2.6, 95% CI 1.4-4.7) were associated with a recent cerebral infarction, whereas luminal stenosis grade was not (P = 0.128). The combination of MTT-ASPECTS and plaque enhancement grade provided incremental information beyond luminal stenosis grade alone. The area under the receiver operating characteristic curve (AUC) improved from 0.535 to 0.921 (P < 0.05).

DATA CONCUSION

Strongly enhanced plaques are associated with a higher likelihood of downstream perfusion impairment. Plaque enhancement and perfusion evaluation may play a complementary role to luminal stenosis in determining the occurrence of acute cerebral infarction.

LEVEL OF EVIDENCE

4 Technical Efficacy: Stage 2 J. Magn. Reson. Imaging 2017.

Incremental Value of Plaque Enhancement in Patients with Moderate or Severe Basilar Artery Stenosis: 3.0 T High-Resolution Magnetic Resonance Study

Aim

To investigate the clinical relevance of plaque's morphological characteristics and distribution pattern using 3.0 T high-resolution magnetic resonance imaging (HRMRI) in patients with moderate or severe basilar artery (BA) atherosclerosis stenosis.

Materials and Methods

Fifty-seven patients (33 symptomatic patients and 24 asymptomatic patients) were recruited for 3.0 T HRMRI scan; all of them had >50% stenosis on the BA. The intraplaque hemorrhage (IPH), contrast-enhancement pattern, and distribution of BA plaques were compared between the symptomatic and asymptomatic groups. Factors potentially associated with posterior ischemic stroke were calculated by multivariate analyses.

Results

Enhancement of BA plaque was more frequently observed in symptomatic than in asymptomatic patients (27/33, 81.8% versus 11/24, 45.8%; p < 0.01). In multivariate regression analysis, plaque enhancement (OR = 7.193; 95% CI: 1.880–27.517; p = 0.004) and smoking (OR = 4.402; 95% CI: 2.218–15.909; p = 0.024) were found to be independent risk factors of posterior ischemic events in patients with BA stenosis >50%. Plaques were mainly distributed at the ventral site (39.3%) or involved more than two arcs (21.2%) in the symptomatic group but were mainly distributed at left (33.3%) and right (25.0%) sites in the asymptomatic group.