Association between the fetal-type posterior cerebral artery and intracranial anterior and posterior circulating atherosclerotic plaques using multi-contrast magnetic resonance vessel wall imaging.

Background: Intracranial atherosclerotic disease (ICAD) is one of the most common causes of ischemic stroke. The fetal-type posterior cerebral artery (FTP) affects intracranial collateral circulation, which is closely related to the occurrence and development of ICAD. Knowledge of the relationship between FTP and ICAD is important for developing treatment strategies for FTP patients diagnosed with atherosclerotic diseases. This study aims to quantitatively analyze the association between the FTP and intracranial atherosclerotic plaques using magnetic resonance vessel wall imaging (VW-MRI). Methods: This retrospective study enrolled patients with recent cerebrovascular symptoms (stroke or transient ischemic attack <2 weeks) who were diagnosed with atherosclerotic plaque(s) by VW-MRI in one hospital from October 2018 to March 2022. They were classified into the FTP group and the non-FTP group. Plaque characteristics and vascular-related parameters in intracranial arteries were compared between the two groups. Univariate and multivariate logistic regressions were performed to determine the odds ratios (ORs) and corresponding 95% confidence intervals (CIs) of the plaque characteristics between the two groups. Results: A total of 104 patients (mean age: 61.8±9.8 years, 57 males) were included for VW-MRI scan analysis. 40 (38.46%) and 64 (61.54%) were classified into the FTP and the non-FTP groups, respectively. The plaques of middle cerebral artery (MCA) in the FTP group were more likely to occur on the dorsal and superior walls of the lumen compared with the non-FTP group (37.50% vs. 17.19%, P=0.001). The remodeling index (RI) of MCA was statistically different between the two groups (1.071±0.267 vs. 0.886±0.235, P=0.007). No significant differences were found in vertebrobasilar artery (VBA) plaque distributions (17.50% vs. 9.38%, 10.00% vs. 12.50%, 20.00% vs. 17.19%, P>0.05) and characteristics between the two groups (RI: 1.095±0.355 vs. 0.978±0.251; eccentricity index: 0.539±1.622 vs. 0.550±0.171, P>0.05). Conclusions: The plaques in the FTP group were more likely to occur on the dorsal and superior walls of the MCA, and the presentence of FTP was found to be significantly correlated with vascular remodeling of MCA atherosclerotic plaques. The relationship between the severity of intracranial atherosclerosis and the presence of FTP can provide valuable information for clinicians to intervene early and prevent the occurrence of stroke.

Association of culprit plaque enhancement ratio, hypoperfusion and HbA1c with recurrent ischemic stroke in patients with atherosclerotic stenosis of the middle cerebral artery.

PURPOSE: To investigate the differences in intracranial culprit plaque characteristics of the middle cerebral artery (MCA), collateral circulation and hypoperfusion in patients with and without recurrent ischemic stroke and to identify the association with the recurrent ischemic cerebrovascular events. METHOD: Eighty-six patients with acute/subacute ischemic stroke caused by atherosclerotic plaques of the MCA were retrospectively enrolled and grouped into patients with recurrence (n = 36) and without recurrence (n = 50). All patients underwent high-resolution vessel wall imaging and dynamic susceptibility contrast-enhanced perfusion weighted imaging. The differences in culprit plaque characteristics, collateral circulation and hypoperfusion in the territory of the stenotic MCA were assessed between the two groups. The relationship between plaque characteristics and hypoperfusion was evaluated. The independent factors of recurrent ischemic stroke were identified by logistic regression analyses. RESULTS: Higher HbA1c, culprit plaque enhancement grade, culprit plaque enhancement ratio, and lower time to peak map based on the Alberta Stroke Program Early CT score (TTP-ASPECTS) were observed in the recurrence group(all p < 0.050). Both plaque enhancement grade and enhancement ratio were significantly associated with TTP-ASPECTS (p = 0.030 and 0.039, respectively). HbA1c, culprit plaque enhancement ratio and TTP-ASPECTS were independent factors of the recurrence of ischemic stroke (all p < 0.050). The area under the curve of the combination including the above factors (AUC = 0.819) was significantly higher than that of any variable alone after adjustment (all p < 0.050). CONCLUSIONS: Culprit plaque enhancement ratio, TTP-ASPECTS and HbA1c were independent factors of recurrent ischemic stroke. Their combination improved the accuracy in identifying the risk of recurrent ischemic stroke.

Association of pre-diabetes and type 2 diabetes mellitus with intracranial plaque characteristics in patients with acute ischemic stroke.

OBJECTIVES: To investigate the association of pre-diabetes(i.e., the early stages of glucometabolic disturbance) and Type 2 diabetes mellitus (T2DM) with intracranial plaque characteristics in patients with acute ischemic stroke using three-dimensional high-resolution MR imaging. METHODS: One hundred and forty-three symptomatic patients with acute ischemic stroke attribute to intracranial atherosclerotic plaque were prospectively enrolled. All participants were further divided into three groups: normal glucose metabolism(non-diabetes) group(n = 41), pre-diabetes group(n = 45), and T2DM group(n = 57) according to glucometabolic status. Culprit plaque characteristics (such as plaque burden, normalized wall index and enhancement ratio), total plaque number, and global plaque enhancement score were analyzed and compared among the three glucometabolic groups. The association between pre-diabetes and T2DM with intracranial plaque characteristics was assessed by logistic regression and multivariate linear regression. RESULTS: Plaque number was higher in patients with pre-diabetes and T2DM compared with those with non-diabetes(3.71 ± 1.83 and 3.75 ± 1.71 vs 2.24 ± 1.46, p = 0.006). Multivariate logistic regression showed a significant association of multiple intracranial plaques with pre-diabetes(OR 3.524, 95% CI 1.082 ~ 11.479, p = 0.037), T2DM(OR 3.760, 95% CI 1.098 ~ 12.872, p = 0.035) and luminal stenotic rate. Both pre-diabetes and T2DM were significantly associated with culprit plaque enhancement ratio(ß = 0.527 and ß = 0.536; respectively; p < 0.001) and global plaque enhancement score(ß = 0.264 and ß = 0.373; respectively; p < 0.05). CONCLUSIONS: Patients with pre-diabetes and T2DM had similar intracranial atherosclerotic plaque vulnerability, as demonstrated by multiple plaques, increased culprit plaque enhancement ratio and global plaque enhancement score. ADVANCES IN KNOWLEDGE: Pre-diabetes might be a risk factor for intracranial plaque vulnerability. It is necessary to monitor a slight increase in blood glucose in non-diabetes patients with acute ischemic stroke.

Collateral Status at Single-Phase and Multiphase CT Angiography versus CT Perfusion for Outcome Prediction in Anterior Circulation Acute Ischemic Stroke.

Background Collateral status assessed with single- or multiphase CT angiography can be used to predict outcome in patients with acute ischemic stroke (AIS); however, little is known about whether these measures could be comparable with CT perfusion parameters. Purpose To compare the predictive ability of collateral score systems assessed with single- or multiphase CT angiography and CT perfusion parameters in determining clinical outcomes in patients with AIS. Materials and Methods In this retrospective study, data obtained from October 2017 to August 2018 in consecutive patients with AIS caused by isolated anterior circulation large artery occlusion and that were obtained within 24 hours after onset were reviewed. The collateral score was assessed by using established scoring systems described by Menon et al. The correlations between single- and multiphase collateral scores, hypoperfusion, and ischemic core volume and final infarct volume (FIV) determined by follow-up diffusion-weighted imaging or unenhanced CT were studied. Receiver operating characteristic curves and multivariable logistic regression analysis were performed to assess the predictive ability of scoring systems and CT perfusion parameters for a favorable clinical outcome. Results A total of 119 patients (median age, 75 years; interquartile range, 66-82 years; 74 men) were included. Both single- and multiphase Menon scores had a moderate negative correlation with FIV (r = -0.43, P < .001; r = -0.44, P < .001). Receiver operating characteristic curve analysis revealed the multiphase Menon score performed better than the single-phase Menon score (area under the curve [AUC], 0.72 vs 0.64; P = .045) in the prediction of a favorable 90-day modified Rankin scale score. There was no difference between multiphase Menon score and hypoperfusion volume (AUC, 0.72 vs 0.72; P = .97) or ischemic core volume (AUC, 0.72 vs 0.71; P = .94). Multivariable analysis showed multiphase Menon score was an independent predictor of good clinical outcomes (odds ratio = 3.04, P = .001). Conclusion Multiphase Menon score performed better than single-phase Menon score and was comparable with CT perfusion parameters in determining clinical outcomes in patients with acute ischemic stroke. © RSNA, 2020.

Penumbra-based radiomics signature as prognostic biomarkers for thrombolysis of acute ischemic stroke patients: a multicenter cohort study.

BACKGROUND AND PURPOSE: This study aimed at developing a radiomics signature (R score) as prognostic biomarkers based on penumbra quantification and to validate the radiomics nomogram to predict the clinical outcomes for thrombolysis for acute ischemic stroke (AIS) patients. METHODS: In total, 168 patients collected from seven centers were retrospectively included. A score of mismatch was defined as MIS. Based on a short-term clinical label, 456 radiomics features were evaluated with feature selection methods. R score was constructed with the selected features. To compare the predictive capabilities of the clinical factors, MIS, and R score, three nomograms were developed and evaluated, according to the short-term clinical assessment on day 7. Finally, the radiomics nomogram was validated by predicting the 3-month clinical outcomes of AIS patients, in an external cohort. RESULTS: R scores were found to be significantly higher in patients with favorable clinical outcomes in both training and validation datasets. The predictive value of the radiomics nomogram estimating favorable clinical outcomes was modest, with a concordance index (C-index) of 0.695 [95% confidence interval (CI) 0.667-0.723) in an external validation dataset. In addition, the area under curve (AUC) of the radiomics nomogram predicting favorable clinical outcome reached 0.886 (95% CI 0.809-0.963) on day 7 and 0.777 (95% CI 0.666-0.888) at 3 months. CONCLUSIONS: The radiomics signature is an independent biomarker for estimating the clinical outcomes in AIS patients. By improving the individualized prediction of the clinical outcome for AIS patients 3 months after onset, the radiomics nomogram adds more value to the current clinical decision-making process.

CT and MR imaging features of pancreatic adenosquamous carcinoma and their correlation with prognosis.

PURPOSE: To retrospectively investigate the computed tomography (CT) and magnetic resonance (MR) imaging features of pancreatic adenosquamous carcinoma (PASC) and the association between imaging findings and prognosis. MATERIALS AND METHODS: CT, MR images of 26 patients with PASC were analyzed. Clinical symptoms, tumor markers, and patients' survival were recorded. Tumor attenuation, enhancement pattern and degree, vessel involvement, adjacent tissue invasion and metastasis were evaluated. The association between imaging features and overall survival (OS) were also assessed using Cox proportional hazards ratio model. RESULTS: Fourteen masses were found in the head of the pancreas and 12 in the body/tail. The mean tumor size was 4.47 ± 1.76 cm. PASC usually showed ill-defined (96.2%), lobulated (76.9%) and predominantly solid mass (92.3%). Ring enhancement in the peripheral area of the tumor was commonly seen (76.9%). Vessel invasion was seen in 17 cases (65.4%), encasement of adjacent arteries in 7 cases (26.9%), upstream main pancreatic duct (MPD) dilatation in 16 cases (61.5%) and double duct sign in 9 cases (34.6%). Multivariate Cox proportional hazards model demonstrated that patients with vessel invasion may predict a poor prognosis (p = 0.037). CONCLUSION: PASC tends to be an ill-defined solid mass with peripheral ring enhancement, and relatively poor enhancement in the central area. PASC may also show vessel invasion, vessel encasement and upstream MPD dilatation. Vessel invasion may indicate a poor prognosis.

Reproducibility of 3.0T High-Resolution Magnetic Resonance Imaging for the Identification and Quantification of Middle Cerebral Arterial Atherosclerotic Plaques.

OBJECTIVE: To assess the reproducibility of 3.0T high-resolution magnetic resonance imaging for the identification and quantification of atherosclerotic plaques in the middle cerebral artery. METHODS: Sixty-nine consecutive patients with ischemic stroke or asymptomatic stenosis (>30%) of the middle cerebral artery underwent 3.0T high-resolution magnetic resonance imaging examinations. Two independent investigators reviewed all images with 1 investigator re-evaluating all images 4 weeks later. Wall characteristics of the middle cerebral artery, including plaque surface morphology, plaque location, plaque components, and burden were identified and measured. RESULTS: Intraobserver and interobserver agreement were all substantial in identifying plaque surface irregularity (k = 0.741, 0.555-0.897; k = 0.685, 0.490-0.843; respectively) and intraplaque hemorrhage (k = 0.654, 0.446-0.838; k = 0.605, 0.369-0.792; respectively). Intraobserver agreement was substantial (k = 0.654) and interobserver agreement was moderate (k = 0.553) for the identification of plaque fibrous caps. The total intraobserver and interobserver reproducibility was almost excellent for the identification of plaque position. With regards to vessel area measurement at the site of maximal lumen narrowing, intraobserver and interobserver reproducibility was excellent (intraclass correlation coefficient was 0.886 and 0.885, respectively) and moderate for lumen area at the site of maximal lumen narrowing (intraclass correlation coefficient was 0.695 and 0.558, respectively). In addition, intraobserver and interobserver reproducibility was excellent for vessel area and lumen area measurements at the reference sites. CONCLUSIONS: The reproducibility of 3.0T high-resolution magnetic resonance imaging for the identification and quantification of artery wall characteristics was overall acceptable. However, the reliability for lumen area measurement at the maximum narrowing site and identification of the fibrous cap needs to be improved.

Isoflurane anesthesia suppresses distortion product otoacoustic emissions in rats.

A commonly used anesthetic, isoflurane, can impair auditory function in a dose-dependent manner. However, in rats, isoflurane-induced auditory impairments have only been assessed with auditory brainstem responses; a measure which is unable to distinguish if changes originate from the central or peripheral auditory system. Studies performed in other species, such as mice and guinea-pigs, suggests auditory impairment stems from disrupted OHC amplification. Despite the wide use of the rat in auditory research, these observations have yet to be replicated in the rat animal model. This study used distortion product otoacoustic emissions to assess outer hair cell function in rats that were anesthetized with either isoflurane or a ketamine/xylazine cocktail for approximately 45 min. Results indicate that isoflurane can significantly reduce DPOAE amplitudes compared to ketamine/xylazine, and that responses were more variable with isoflurane than ketamine/xylazine over the 45-min test period. Based on these observations, isoflurane should be used with caution when assessing peripheral auditory function to avoid potentially confounding effects.

Prolonged low-level noise exposure reduces rat distortion product otoacoustic emissions above a critical level.

Prolonged noise exposures presented at low to moderate intensities are often used to investigate neuroplastic changes in the central auditory pathway. A common assumption in many studies is that central auditory changes occur independent of any hearing loss or cochlear dysfunction. Since hearing loss from a long term noise exposure can only occur if the level of the noise exceeds a critical level, prolonged noise exposures that incrementally increase in intensity can be used to determine the critical level for any given species and noise spectrum. Here we used distortion product otoacoustic emissions (DPOAEs) to determine the critical level in male, inbred Sprague-Dawley rats exposed to a 16-20 kHz noise that increased from 45 to 92 dB SPL in 8 dB increments. DPOAE amplitudes were largely unaffected by noise presented at 60 dB SPL and below. However, DPOAEs within and above the frequency band of the exposures declined rapidly at noise intensities presented at 68 dB SPL and above. The largest and most rapid decline in DPOAE amplitude occurred at 30 kHz, nearly an octave above the 16-20 kHz exposure band. The rate of decline in DPOAE amplitude was 0.54 for every 1 dB increase in noise intensity. Using a linear regression calculation, the estimated critical level for 16-20 kHz noise was remarkably low, approximately 60 dB SPL. These results indicate that long duration, 16-20 kHz noise exposures in the 65-70 dB SPL range likely affect the cochlea and central auditory system of male Sprague-Dawley rats.

Development and validation of a penumbra-based predictive model for thrombolysis outcome in acute ischemic stroke patients.

The use of thrombolysis in acute ischemic stroke is restricted to a small proportion of patients because of the rigid 4·5-h window. With advanced imaging-based patient selection strategy, rescuing penumbra is critical to improving clinical outcomes. In this study, we included 155 acute ischemic stroke patients (84 patients in training dataset, age from 43 to 80, 59 males; 71 patients in validation dataset, age from 36 to 80, 45 males) who underwent MR scan within the first 9-h after onset, from 7 independent centers. Based on the mismatch concept, penumbra and core area were identified and quantitatively analyzed. Moreover, predictive models were developed and validated to provide an approach for identifying patients who may benefit from thrombolytic therapy. Predictive models were constructed, and corresponding areas under the curve (AUC) were calculated to explore their performances in predicting clinical outcomes. Additionally, the models were validated using an independent dataset both on Day-7 and Day-90. Significant correlations were detected between the mismatch ratio and clinical assessments in both the training and validation datasets. Treatment option, baseline systolic blood pressure, National Institutes of Health Stroke Scale score, mismatch ratio, and three regional radiological parameters were selected as biomarkers in the combined model to predict clinical outcomes of acute ischemic stroke patients. With the external validation, this predictive model reached AUCs of 0·863 as short-term validation and 0·778 as long-term validation. This model has the potential to provide quantitative biomarkers that aid patient selection for thrombolysis either within or beyond the current time window.

Regional Coherence Alterations Revealed by Resting-State fMRI in Post-Stroke Patients with Cognitive Dysfunction.

OBJECTIVES: Post-stroke cognitive dysfunction greatly influences patients' quality of life after stroke. However, its neurophysiological basis remains unknown. This study utilized resting-state functional magnetic resonance imaging (fMRI) to investigate the alterations in regional coherence in patients after subcortical stroke. METHODS: Resting-state fMRI measurements were acquired from 16 post-stroke patients with poor cognitive function (PSPC), 16 post-stroke patients with good cognitive function (PSGC) and 30 well-matched healthy controls (HC). Regional homogeneity (ReHo) was used to detect alterations in regional coherence. Abnormalities in regional coherence correlated with scores on neuropsychological scales. RESULTS: Compared to the HC and the PSGC, the PSPC showed remarkably decreased ReHo in the bilateral anterior cingulate cortex and the left posterior cingulate cortex/precuneus. ReHo in the bilateral anterior cingulate cortex positively correlated with the scores on the Symbol Digit Modalities Test (r = 0.399, P = 0.036) and the Complex Figure Test-delayed recall subtest (r = 0.397, P = 0.036) in all post-stroke patients. Moreover, ReHo in the left posterior cingulate cortex/precuneus positively correlated with the scores on the Forward Digit Span Test (r = 0.485, P = 0.009) in all post-stroke patients. CONCLUSIONS: Aberrant regional coherence was observed in the anterior and posterior cingulate cortices in post-stroke patients with cognitive dysfunction. ReHo could represent a promising indicator of neurobiological deficiencies in post-stroke patients.

Wall characteristics and mechanisms of ischaemic stroke in patients with atherosclerotic middle cerebral artery stenosis: a high-resolution MRI study.

OBJECTIVE: To evaluate the characteristics of atherosclerotic middle cerebral artery (MCA) stenosis by high-resolution magnetic resonance imaging (HR-MRI) and determine the relationship between wall characteristics and infarction patterns. METHODS: Thirty-six patients with acute ischaemic stroke due to MCA stenosis underwent diffusion-weighted magnetic resonance imaging (DWI) and HR MRI. Wall characteristics of MCA, including irregular surface, superior location, T2-hyperintense of plaques and positive remodelling (PR), were analysed. Characteristics of acute infarct on DWI were categorised according to the number (single or multiple infarcts) and the pattern of cerebral infarcts (cortical, border zone or perforating artery territory infarcts). The relationship between wall characteristics and infarction patterns was evaluated. RESULTS: PR was observed in 20 patients, irregular surface plaque in 18 patients, superior location of plaques in 14 patients and T2-hyperintense foci in 13 patients. Seventeen patients had multiple acute cerebral infarcts and 13 showed single acute cerebral infarcts. Border zone infarcts were the most common (76.5%) among multiple acute infarcts. Penetrating artery infarcts (PAI) accounted for 76.9% of all single infarcts. Multiple infarcts were more frequently observed in patients with PR (P = 0.007) or plaque surface irregularity (P = 0.035). Single infarcts, especially PAI, were more prevalent in patients with superior plaque (P = 0.030). No statistically significant differences were observed between multiple and single infarcts in patients with T2-hyperintense lesions (P = 0.638). CONCLUSIONS: PR or irregular surface plaques were associated with artery-to-artery embolism. Superior location of plaques was associated with PAI. HR-MRI provides insights into intracranial atherosclerosis in vivo, predictive of infarction patterns.

High-resolution MRI of the vessel wall in patients with symptomatic atherosclerotic stenosis of the middle cerebral artery.

Intracranial atherosclerosis is associated with recurrent ischemic stroke. High-resolution MRI (HR MRI) can provide information about atheroma in vivo. We aimed to analyze and compare vascular wall imaging characteristics between patients with symptomatic and asymptomatic atherosclerotic stenosis of the middle cerebral artery (MCA) using 3.0 Tesla HR MRI. The HR MRI protocol included four different scans: black blood T1-weighted, T2-weighted and proton density-weighted MRI, as well as three-dimensional turbo spin echo imaging techniques with multiplanar reconstruction. Plaque characteristics, including location, morphology, and signal intensity, were analyzed in 51 patients (29 symptomatic, 22 asymptomatic) with atherosclerotic stenosis of the middle cerebral artery. The vessel wall area, lumen area, and plaque area (PA) were also calculated and compared between the symptomatic and asymptomatic groups. We found that PA, remodeling index (RI), and positive remodeling (PR) prevalence were significantly greater in the symptomatic group than in the asymptomatic group (PA: p=0.033; RI: p=0.020; PR: p=0.032). Plaque location in the superior aspect of the vessel wall and irregular plaque surface were more frequently observed in the symptomatic group than in the asymptomatic group (superior location: p=0.031; irregular surface: p=0.036). Moreover, multivariate logistic regression identified plaque location on the superior wall as an independent predictor of symptomatic MCA stenosis (odds ratio: 4.471; p=0.039). Therefore, we can conclude that patients with symptomatic atherosclerotic stenosis of the MCA are more likely to have larger plaques, PR, superiorly located plaques, and irregular plaque surface. These characteristics are promising factors for stratifying stroke risk.

Combination therapy of transcatheter arterial chemoembolization and arterial administration of antiangiogenesis on VX2 liver tumor.

PURPOSE: This study was designed to evaluate the antitumorigenic efficiency of Endostar (an antiangiogenic agent) arterially administrated combined with transcatheter arterial chemoembolization (TACE) on liver tumor, and validation of perfusion CT for quantitative measurements of the results. EXPERIMENTAL DESIGN: Thirty rabbits bearing VX2 liver tumors were randomly and equally distributed into three groups. One of the following treatment protocols was performed in each group: 1) group 1 was treated with TACE and simultaneously arterially administrated Endostar; 2) group 2 with TACE alone, and 3) a control group that had saline injected through hepatic artery. Routine CT scan was performed before treatment, and perfusion CT imaging was performed 2 weeks after treatment. Immunohistochemical biomarkers of microvascular density (MVD) and the expression of vascular endothelial growth factor (VEGF) were measured for assessments of angiogenesis. RESULTS: We observed a statistically significant reduction from the control in the volume, growth rate, and size of the tumor 2 weeks after treatment with both TACE plus Endostar and with TACE alone (P < 0.01). Although there was no statistically significant difference in tumor size between the group with TACE plus Endostar and the group with TACE alone (P > 0.05), MVD and VEGF were significantly less expressed in the TACE plus Endostar group than both groups with TACE alone and the control group (P < 0.01). Blood flow (BF), blood volume (BV), and permeability-surface area products (PS) in the group with TACE plus Endostar on perfusion CT were significantly higher than other two groups (P < 0.05), which were positively correlated with the MVD and VEGF values (P < 0.05). CONCLUSIONS: TACE with arterial administration of Endostar simultaneously significantly inhibited the angiogenesis biomarkers associated with TACE in a rabbit model bearing VX2 liver tumor, which indicates that the combined treatment protocol may have potential synergistic effects on liver cancer. It also is suggested that perfusion CT may be useful for monitoring antiangiogenic/antivascular treatment in the liver tumors.