Asymmetrically hypointense veins on T2*w imaging and susceptibility-weighted imaging in ischemic stroke

SWI brush sign of cerebral parenchymal veins in central nervous system diseases

Brush sign (BS) was first reported as prominent hypointensity of deep medullary veins and subependymal veins on T2*-weighted images at 3 T MRI in patients with acute stroke in the territory of the middle cerebral artery. Subsequently, BS in central nervous system (CNS) diseases such as moyamoya disease, cerebral venous thrombosis, and Sturge-Weber syndrome was also described on susceptibility-weighted imaging (SWI), and the clinical implications of BS were discussed. The purpose of this review is to demonstrate BS on SWI in various CNS diseases and its mechanisms in the above-mentioned diseases. We also explain the clinical implications of this finding in each disease.

Multiple Hypointense Vessels are Associated with Cognitive Impairment in Patients with Single Subcortical Infarction

We aimed to explore the relationship between multiple hypointense vessels and cognitive function in patients with single subcortical infarction (SSI) and the role of SSI with different etiological mechanisms in the above relationship. Multiple hypointense vessels were measured by the number of deep medullary veins (DMVs), DMVs score, and cortical veins (CVs) score. The Montreal Cognitive Assessment (MoCA), the Shape Trail Test (STT), and the Stroop Color and Word Test (SCWT) were assessed to evaluate cognitive function. SSI was dichotomized as branch atheromatous disease (BAD) and cerebral small vessel disease (CSVD)-related SSI by whole-brain vessel-wall magnetic resonance imaging. We included a total of 103 acute SSI patients. After adjustments were made for related risk factors of cognitive function, the SSI patients with higher DMVs score were more likely to have longer STT-B (P = 0.001) and smaller STT-B-1 min (P = 0.014), and the SSI patients with higher CVs score were more likely to have shorter STT-A (P = 0.049). In subgroup analysis, we found that the negative relationship between DMVs scores and cognitive function and the positive relationship between CVs scores and cognitive function were significantly stronger in BAD patients. We provided valuable insights into the associations between DMVs, CVs, and multi-domain cognitive impairment in SSI patients, which underscored the necessity to further study the dynamic alterations of venules and their specific influence on post-stroke cognitive impairment.

Unveiling metabolic patterns in dementia: Insights from high-resolution quantitative blood-oxygenation-level-dependent MRI

BACKGROUND

Oxygen extraction fraction (OEF) and deoxyhemoglobin (DoHb) levels reflect variations in cerebral oxygen metabolism in demented patients.

PURPOSE

Delineating the metabolic profiles evident throughout different phases of dementia necessitates an integrated analysis of OEF and DoHb levels. This is enabled by leveraging high-resolution quantitative blood oxygenation level dependent (qBOLD) analysis of magnitude images obtained from a multi-echo gradient-echo MRI (mGRE) scan performed on a 3.0 Tesla scanner.

METHODS

Achieving superior spatial resolution in qBOLD necessitates the utilization of an mGRE scan with only four echoes, which in turn limits the number of measurements compared to the parameters within the qBOLD model. Consequently, it becomes imperative to discard non-essential parameters to facilitate further analysis. This process entails transforming the qBOLD model into a format suitable for fitting the log-magnitude difference (L-MDif) profiles of the four echo magnitudes present in each brain voxel. In order to bolster spatial specificity, the log-difference qBOLD model undergoes refinement into a representative form, termed as r-qBOLD, particularly when applied to class-averaged L-MDif signals derived through k-means clustering of L-MDif signals from all brain voxels into a predetermined number of clusters. The agreement between parameters estimated using r-qBOLD for different cluster sizes is validated using Bland-Altman analysis, and the model's goodness-of-fit is evaluated using aχ 2 ${\chi ^2}$ -test. Retrospective MRI data of Alzheimer's disease (AD), mild cognitive impairment (MCI), and non-demented patients without neuropathological disorders, pacemakers, other implants, or psychiatric disorders, who completed a minimum of three visits prior to MRI enrolment, are utilized for the study.

RESULTS

Utilizing a cohort comprising 30 demented patients aged 65-83 years in stages 4-6 representing mild, moderate, and severe stages according to the clinical dementia rating (CDR), matched with an age-matched non-demented control group of 18 individuals, we conducted joint observations of OEF and DoHb levels estimated using r-qBOLD. The observations elucidate metabolic signatures in dementia based on OEF and DoHb levels in each voxel. Our principal findings highlight the significance of spatial patterns of metabolic profiles (metabolic patterns) within two distinct regimes: OEF levels exceeding the normal range (S1-regime), and OEF levels below the normal range (S2-regime). The S1-regime, accompanied by low DoHb levels, predominantly manifests in fronto-parietal and perivascular regions with increase in dementia severity. Conversely, the S2-regime, accompanied by low DoHb levels, is observed in medial temporal (MTL) regions. Other regions with abnormal metabolic patterns included the orbitofrontal cortex (OFC), medial-orbital prefrontal cortex (MOPFC), hypothalamus, ventro-medial prefrontal cortex (VMPFC), and retrosplenial cortex (RSP). Dysfunction in the OFC and MOPFC indicated cognitive and emotional impairment, while hypothalamic involvement potentially indicated preclinical dementia. Reduced metabolic activity in the RSP suggested early-stage AD related functional abnormalities.

CONCLUSIONS

Integrated analysis of OEF and DoHb levels using r-qBOLD reveals distinct metabolic signatures across dementia phases, highlighting regions susceptible to neuronal loss, vascular involvement, and preclinical indicators.

SWI and CTP fusion model based on sparse representation method to predict cerebral infarction trend

Objective

SWI image signal is related to venous reflux disorder and perfusion defect. Computed tomography perfusion (CTP) contains perfusion information in space and time. There is a complementary basis between them to affect the prognosis of cerebral infarction.

Methods

Sixty-six patients included in the retrospective study were designated as the training set. Effective perfusion indicator features and imaging radiomic features of the peri-infarction area on Susceptibility weighted imaging (SWI) and CTP modality images were extracted from each case. Thirty-three patients from the prospectively included group were designated as the test set of the machine learning model based on a sparse representation method. The predicted results were compared with the DWI results of the patients' 7-10 days review to assess the validity and accuracy of the prediction.

Results

The AUC of the SWI + CTP integrated model was 0.952, the ACC was 0.909, the SEN was 0.889, and the SPE was 0.933. The prediction performance is the highest. Compared with the value of AUC: the SWI model is 0.874, inferior to the performance of the SWI + CTP model, and the CTP model is 0.715.

Conclusion

The prediction efficiency of the changing trend of infarction volume is further improved by the correlation between the combination of the two image features.

Brush Sign on pre-treatment imaging is associated with good functional outcome in stroke patients treated with mechanical thrombectomy: A prospective monocentric study

BACKGROUND

The Brush Sign (BrS) is a radiological biomarker (MRI) showing signal decrease of subependymal and deep medullary veins on paramagnetic-sensitive magnetic resonance sequences. Previous studies have shown controversial results regarding the prognostic value of BrS. We aimed to assess whether BrS on T2*-weighted sequences could predict functional prognosis in patients treated with mechanical thrombectomy (MT).

METHODS

We included all consecutive patients with large artery occlusion related stroke in anterior circulation treated with MT between February 2020 and August 2022 at Reims University Hospital. Multivariable logistic regression models were used to investigate factors associated with BrS and its impact on outcomes.

RESULTS

Of the 327 included patients, 124 (37,9%) had a BrS on baseline MRI. Mean age was 72 ± 16 years and 184 (56,2 %) were female. In univariate analysis, BrS was associated with a younger age (67 vs 74; p<0.001), a higher NIHSS score (16(10-20) vs 13(8-19); p = 0.047) history of diabetes (15.3% vs 26.1 %; p = 0.022) and a shorter onset to MRI time (145.5 (111.3-188.5) vs 162 (126-220) p = 0.008). In multivariate analyses, patients with a BrS were younger (OR:0.970 (0.951 - 0.989)), tend to have a higher NIHSS score at baseline (OR:1.046 (1.000 - 1.094) and were less likely to have diabetes (OR: 0.433; 0.214-0.879). The presence of BrS was independently associated with functional independence (OR: 2.234(1.158-4,505) at 3 months but not with mortality nor with symptomatic intracerebral hemorrhage.

CONCLUSION

BrS on pre-treatment imaging could be considered as a biomarker of physiological adaptation to cerebral ischemia, allowing prolonged viability of brain tissue and might participate in the therapeutic decision.

Analysis of the posterior cerebral perfusion status and clinical prognostic value in chronic unilateral middle cerebral artery occlusion using SWAN combined with 3D-ASL

To investigate the predictive value of T2 star-weighted angiography (SWAN) combined with 3-dimensional (3D) arterial spin labeling (3D-ASL) to assess cerebral perfusion status and clinical prognosis in chronic unilateral middle cerebral artery (MCA) M1 occlusion. This study included 55 patients diagnosed with chronic unilateral MCA M1 occlusion using 3D time-of-flight magnetic resonance angiography between January 2018 and July 2022. Based on the prominent vessel sign (PVS) shown in the SWAN sequence, the patients were divided into PVS-positive (n = 26) and PVS-negative (n = 29) groups. Cerebral blood flow (CBF) was selected in the affected regions of the frontal, parietal, and temporal lobes (regions of interest = 200 ± 20 mm2) using pseudo-color maps in the 3D-ASL sequence. Each patient was followed up for ischemic cerebrovascular disease within 12 months of diagnosis. The collected data were statistically analyzed to evaluate the predictive value of SWAN and 3D-ASL for the clinical prognosis of patients with chronic unilateral MCA M1 occlusion. Patients were divided into 2 groups based on the occurrence of an ischemic cerebrovascular event within 12 months (ischemic cerebrovascular event [acute ischemic stroke + transient ischemic attack] and non-ischemic cerebrovascular event groups, including 30 and 25 cases, respectively). The incidence of ischemic cerebrovascular events within 12 months was significantly higher in the PVS-positive group than in the PVS-negative group (92.31% vs 20.69%). Furthermore, the CBF values of the affected frontal, parietal, and temporal lobes were significantly lower in the ischemic cerebrovascular event group than in the non-ischemic cerebrovascular event group (P < .05). According to the receiver operating characteristic curve, the CBF values of the affected frontal, parietal, and temporal lobes in patients with chronic unilateral MCA M1 occlusion strongly correlated with ischemic cerebrovascular disease within 12 months. PVS-negative display and good collateral circulation were closely related to clinical prognosis in patients with chronic unilateral MCA M1 occlusion.

FLAIR vascular hyperintensity combined with asymmetrical prominent veins in acute anterior circulation ischemic stroke: prediction of collateral circulation and clinical outcome

BACKGROUND

To investigate the value of fluid-attenuated inversion recovery vascular hyperintensity (FVH) within asymmetrical prominent veins sign (APVS) on susceptibility-weighted imaging predicting collateral circulation and prognosis in patients with acute anterior circulation ischemic stroke.

METHOD

Patients with severe stenosis or occlusion of ICA or MCA M1, who underwent MRI within 72 h from stroke onset were reviewed. The Alberta Stroke Program Early CT Score was used to evaluate the volume of infarction on DWI, the degree of FVH and APVS. Spearman correlation analysis was used to evaluate the correlation between FVH and APVS. All patients were divided into the good prognosis group and the poor prognosis group according to the score of the modified ranking scale (mRS) 90 days after the stroke. Logistic regression analysis was used to explore the relationship between FVH and APVS and functional prognosis, while receiver operating characteristic (ROC) curves were plotted to assess the value of FVH and APVS in predicting prognosis.

RESULTS

Spearman correlation analysis revealed moderate positive correlations between FVH and APVS (r = 0.586, P < 0.001). The poor prognosis group had a higher rate of a history of atrial fibrillation, a larger cerebral infarction volume, a higher NIHSS score at admission, and a higher FVH and APVS score compared with the good prognosis group (all P < 0.05). A further logistic regression indicated that the NIHSS score, cerebral infarction volume, FVH and APVS were independent risk factors for a poor functional prognosis. In terms of FVH, APVS, alone and their combination for the diagnosis of poor prognosis, the sensitivity, specificity, area under the ROC curve (AUC), and 95% confidence interval (CI) were 86.8%, 83.3%, 0.899 (95% CI 0.830-0.968); 60.5%, 93.7%, 0.818 (95% CI 0.723-0.912); 86.8%, 89.6%, 0.921 (95% CI 0.860-0.981), respectively.

CONCLUSION

The presence of FVH and APVS can provide a comprehensive assessment of collateral circulation from the perspective of veins and arteries, and the correlation between the two is positively correlated. Both of them were independent risk factors for poor prognosis, their combination is complementary and can improve the predictive value.

Prominent veins sign is associated with malignant cerebral edema after acute ischemic stroke

Malignant cerebral edema (MCE) is often associated with severe physical disability and a high mortality rate. The current prediction of MCE is focused on infarct volume, and tools are relatively lacking. The prominent veins sign (PVS-SWI) is considered a marker of severely impaired tissue perfusion. This study aimed to determine whether PVS-SWI is associated with early-onset MCE. Patients with acute ischemic stroke (AIS) due to severe large arterial stenosis or occlusion (SLASO) from June 2018 to June 2020 were included. The ASPECTS score assessed the extent of PVS-SWI, and 4-10 was defined as a positive group. The primary outcome was MCE, defined as the deterioration of neurological function and midline structural excursions of >5 mm during hospitalization. The secondary outcomes included worsening of the NIHSS by ≥ 2 points, in-hospital death, and death within 1 year after stroke. Logistic regression was used to assess the correlation between PVS-SWI and outcomes. The study included 157 patients， 40 (25.5%) of whom developed MCE. PVS-SWI was more prevalent in patients who developed MCE (75.0% vs 45.3%; P = 0.001). In multivariate regression analysis, PVS-SWI was an independent predictor of MCE development in patients with larger infarct sizes (OR: 4.00， 95%CI: 1.54-10.35，p = 0.004). In patients with small infarct sizes, PVS-SWI was an independent predictor of a worsening NIHSS of ≥2(OR: 11.13， 95%CI: 2.26-54.89， p = 0.003）. However, PVS-SWI was not associated with death. The main finding of our study was that in patients with larger infarct sizes, a positive PVS-SWI increased the risk of developing MCE. In these patients, more interventions may be needed.

Association Between Cerebral Angiography and Asymmetrical Cortical and Deep/Medullary Vein Signs on T2 Star Magnetic Resonance Imaging in Patients with Hyperacute Horizontal Segment of the Middle Cerebral Artery Occlusion

BACKGROUND

When treating acute ischemic stroke patients, evaluation of collateral flow to the ischemic area is essential. Blood-oxygen-level-dependent imaging, including T2 star (T2∗), can identify elevated deoxyhemoglobin levels, reflecting an increase in the oxygen extraction fraction. Prominent veins on T2∗ represent increased deoxyhemoglobin and cerebral blood volume. This study compared asymmetrical vein signs (AVSs) on T2∗ and digital subtraction angiography findings during mechanical thrombectomy (MT) in patients with hyperacute middle cerebral artery occlusion.

METHODS

Clinical and imaging data of 41 patients with occlusion of the horizontal segment of the middle cerebral artery who underwent MT were collected. Patients were divided into 2 groups based on angiographic occlusion sites as: proximal and distal to the lenticulostriate artery (LSA). AVSs on T2∗ were divided into asymmetrical cortical vein sign (cortical AVS) and asymmetrical deep/medullary vein sign (deep/medullary AVS), and were compared with the findings of intraoperative digital subtraction angiography.

RESULTS

Twenty-seven patients had AVSs. Cortical AVS was the only parameter with a significant association with poor angiographic collateral supply. In terms of occlusion site, deep/medullary AVS was the only parameter with a significant association with occlusion proximal to the LSA.

CONCLUSIONS

In patients with occlusion of the horizontal segment of the middle cerebral artery, presence of the cortical AVS on T2∗ suggests a poor angiographic collateral supply, while presence of the deep/medullary AVS suggests impaired blood flow to the basal ganglia through LSAs. Both these signs contribute to poor outcomes in patients undergoing MT.

The role of asymmetrical prominent veins sign in early neurological deterioration of acute ischemic stroke patients

Background and purpose

Asymmetrical prominent veins sign (APVS) often appears on susceptibility-weighted angiography (SWAN) images in patients with acute stroke. Early neurological deterioration (END) is highly correlated with survival prognosis in patients with ischemic stroke. This study sought to explore the relationship between APVS and END in patients with acute stroke.

Methods

The subjects retrospectively enrolled in this study were patients with acute ischemic stroke in the middle cerebral artery supply area. All patients underwent head MRI, including the SWAN sequence, within 7 days of stroke symptom onset. END was defined as clinical deterioration or recurrence within 72 h after ischemic stroke. The volume of infarction on diffusion-weighted imaging was measured. Univariate and multivariate analyses were used to analyze the relationship between APVS and END. Spearman correlation between APVS grades and infarct volume, white matter hyperintensity (WMH) volume, and offending vessel were also analyzed.

Results

A total of 157 patients with middle cerebral artery infarct between September 2018 and April 2020 were included in the study. APVS appeared on MRI in 84 of 157 patients, and 34 of 157 patients were diagnosed with END. In patients with END, the proportion of severe APVS was higher than in patients without END (P = 0.001, x² = 14.659). Patients with END were older and had a larger volume of infarct and WMH than patients without END (all P < 0.05). After adjustments were made for related risk factors of END, the severity of APVS was still related to END (OR = 2.56, 95% CI, 1.38–4.75; P for trend = 0.003). Spearman correlation showed that APVS grades were positively related to infarct volume (r = 0.289, P < 0.001) and 3-month modified Rankin Scale score (r = 0.203, P = 0.011) and negatively related to offending vessels (r = −0.170, P = 0.034).

Conclusion

APVS may be an important predictor of END in patients with acute ischemic stroke.

Diagnostic utility of T2*-weighted GRE in migraine with aura attack. The cortical veins sign

OBJECTIVE

To evaluate the frequency, distribution, and clinical associations of the dilated appearance of cerebral cortical veins, termed cortical veins sign on T2*-weighted gradient recalled-echo (T2*-GRE) in the acute setting of migraine with aura attack in adult patients.

METHODS

We conducted a retrospective analysis of 60 consecutive patients admitted for acute neurological symptoms with a final diagnosis of migraine with aura (42%) or probable migraine with aura (58%) who underwent emergency brain magnetic resonance imaging and 60 non-migrainous control adults. The cortical veins sign was defined as a marked hypo-intensity and/or an apparent increased diameter of at least one cortical vein. We examined the prevalence, the spatial distribution, and the associations of cortical veins sign with clinical characteristics of migraine with aura.

RESULTS

We detected the cortical veins sign in 25 patients (42%) with migraine with aura, compared to none in the control group (p < 0.0001). The spatial distribution of cortical veins sign was characterised by the predominantly bilateral and posterior location. Presence of cortical veins sign was associated with increased severity of aura (p = 0.05), and shorter delay to MRI (p = 0.02).

CONCLUSION

In the setting of acute neurological symptoms, the presence of cortical veins sign is frequent in patients with migraine with aura and can be detected with good reliability. This imaging marker may help clinicians identify underlying migraine with aura.

Does the Brush-Sign Reflect Collateral Status and DWI-ASPECTS in Large Vessel Occlusion?

Introduction

The relevance of the brush-sign remained poorly documented in large vessel occlusion (LVO). We aimed to assess the relationship between the brush-sign and collateral status and its potential impact on baseline diffusion-weighted imaging–Alberta Stroke Program Early Computed Tomography Score (DWI-ASPECTS) in acute ischemic stroke (AIS) patients eligible to mechanical thrombectomy (MT).

Methods

Consecutive patients admitted in the Lyon Stroke Center with anterior circulation AIS due to intracranial internal carotid artery (ICA) and/or M1 or M2 segment of the middle cerebral artery (MCA) occlusion eligible for MT were included. The brush-sign was assessed on T2-gradient-echo MRI. Collateral status was assessed on digital subtraction angiography according to the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) score.

Results

In this study, 504 patients were included, among which 171 (33.9%) patients had a brush-sign. Patients with a brush-sign more frequently had a poor collateral status [72 (42.1%) vs. 103 (30.9%); p = 0.017]. In univariable analysis, a DWI-ASPECTS < 7 was associated with a brush sign. Following multivariable analysis, the brush-sign no longer affected DWI-ASPECTS < 7 while the latter remained associated with younger age [odds ratio (OR) 0.97, 95% CI.96–0.99], male sex (OR 1.79, 95% CI 1.08–2.99), a higher National Institutes of Health Stroke Scale (NIHSS) score (OR 1.16, 95% CI 1.1–1.21), a poor collateral status (OR 9.35, 95% CI 5.59-16.02), MCA segment (OR 2.54, 95% CI 1.25–5.38), and intracranial ICA (OR 3.01, 95% CI 1.16–8) occlusion.

Conclusions and Relevance

The brush-sign may be a marker of poor collateral status but did not independently predict a lower DWI-ASPECTS.

Clinical Trial Registration

ClinicalTrials.gov, identifier: NCT04620642.

Dynamic Changes of Asymmetric Cortical Veins Relate to Neurologic Prognosis in Acute Ischemic Stroke

Background Cerebral oxygenation is closely related to neural function in acute ischemic stroke (AIS) and can be measured noninvasively from asymmetrically prominent cortical veins (APCVs) using quantitative susceptibility mapping (QSM). Purpose To quantify venous oxygen saturation (SvO₂) using brain MRI with QSM in patients with AIS, to analyze its change at 2-week follow-up, and to assess the influence of SvO₂ in clinical prognosis. Materials and Methods Between 2016 and 2020, consecutive patients with AIS who underwent brain MRI within 24 hours from symptom onset and 2 weeks after treatment were retrospectively enrolled. The SvO₂ of APCVs was quantified using QSM. The independent sample t test was used to compare the SvO₂ between patients with and patients without APCVs. The paired sample t test was used to assess the dynamic change in SvO₂. Pearson and Spearman correlation analysis was used to explore the relationship among dynamic change in SvO₂ and hypoperfusion, National Institutes of Health Stroke Scale (NIHSS) score change, and 90-day modified Rankin Scale (mRS) score. The independent sample t test was used to compare the dynamic change in SvO₂ between different clinical prognoses and outcome subgroups. Results APCVs were detected in 39 of 73 patients (mean age, 70 years ± 10 [standard deviation]; 49 men) at admission and disappeared in 35 patients at 2-week follow-up MRI. The mean SvO₂ increased from 35.0% ± 5.8 to 64.5% ± 10.0 (P < .001) in 39 patients. For the 35 patients with APCVs that disappeared, the dynamic change in SvO₂ negatively correlated with change in NIHSS score (r = -0.37, R² = 0.19, P = .03) and 90-day mRS score (r = -0.54, R² = 0.27, P = .001), and the dynamic change in SvO₂ in the subgroup with good 90-day outcomes (n = 19) was greater than that in the subgroup with poor 90-day outcomes (n = 16) (mean, 34.5% ± 5.8 vs 29.7% ± 6.3; 95% CI: 0.6, 8.9; P = .03). Conclusion Improved oxygen saturation of asymmetric cortical veins detected using brain MRI with quantitative susceptibility mapping corresponded with better acute ischemic stroke outcomes for patients with asymmetrically prominent cortical veins that disappeared at 2-week follow-up MRI. © RSNA, 2021 Online supplemental material is available for this article.

Factors associated with prominent vessel sign on susceptibility-weighted imaging in acute ischemic stroke

The prominent vessel sign (PVS) on susceptibility-weighted imaging (SWI) is not displayed in all cases of acute ischemia. We aimed to investigate the factors associated with the presence of PVS in stroke patients. Consecutive ischemic stroke patients admitted within 24 h from symptom onset underwent emergency multimodal MRI at admission. Associated factors for the presence of PVS were analyzed using univariate analyses and multivariable logistic regression analyses. A total of 218 patients were enrolled. The occurrence rate of PVS was 55.5%. Univariate analyses showed significant differences between PVS-positive group and PVS-negative group in age, history of coronary heart disease, baseline NIHSS scores, total cholesterol, hemoglobin, anterior circulation infarct, large vessel occlusion, and cardioembolism. Multivariable logistic regression analyses revealed that the independent factors associated with PVS were anterior circulation infarct (odds ratio [OR] 13.7; 95% confidence interval [CI] 3.5–53.3), large vessel occlusion (OR 123.3; 95% CI 33.7–451.5), and cardioembolism (OR 5.6; 95% CI 2.1–15.3). Anterior circulation infarct, large vessel occlusion, and cardioembolism are independently associated with the presence of PVS on SWI.

Correlation Between Cerebral Venous Oxygen Level and Cognitive Status in Patients With Alzheimer's Disease Using Quantitative Susceptibility Mapping

Purpose

To quantitatively assess the blood oxygen levels of the cerebral vein using quantitative susceptibility mapping (QSM), and to analyze the correlation between magnetic susceptibility value (MSV) and clinical laboratory indicators/cognitive scores in patients with Alzheimer's disease (AD).

Materials and Methods

Fifty-nine patients (21 males and 38 females) with clinically confirmed AD (AD group) and 22 control subjects (12 males, 10 females; CON group) were recruited. Clinical data and laboratory examination indexes were collected. All patients underwent Mini-mental State Examination, Montreal Cognitive Assessment, Clock Drawing Task, and Activity of Daily Living Scale test, as well as a routine MRI and enhanced gradient echo T2 star weighted angiography (ESWAN).

Results

Higher cerebral venous MSV was observed in AD group compared to CON group, significant differences were observed for bilateral thalamus veins and left dentate nucleus veins. The MSV of bilateral thalamus veins, bilateral internal cerebral veins, and bilateral dentate nucleus veins had significant negative correlation with Mini-mental State Examination score; the MSV of bilateral thalamus veins, bilateral dentate nucleus veins, right septal vein had a significant negative correlation with Montreal Cognitive Assessment scores; a significant negative correlation between the MSV of bilateral thalamus veins, left dentate nucleus vein, right septal vein and the Clock Drawing Task score; the MSV of bilateral thalamus veins, left dentate nucleus vein had a significant negative correlation with Activity of Daily Living Scale score. The MSV of left dentate nucleus vein was positively correlated with the course of the disease, the MSV of bilateral septal vein were positively correlated with the total cholesterol, and the MSV of left septal vein had a positive correlation with LDL.

Conclusion

Decreasing cerebral venous oxygen level in AD patients may affect cognitive status, and associated with the deterioration of the disease in AD patients.

The Prognostic Impact of Susceptibility-Weighted Imaging Prominent Veins in Acute Ischemic Stroke: A Systematic Review and Meta-Analysis

PURPOSE

We aimed to determine the prognostic impact of prominent veins (PVS) after an acute ischemic stroke identified on susceptibility-weighted imaging (PVS-SWI).

METHODS

We searched for studies published in PubMed, Embase, Cochrane Library and Chinese Biomedical Literature Database. Poor functional prognosis, early neurological deterioration, and hemorrhagic transformation were evaluated. Risk ratios (RR) were pooled implementing a random effect model. We performed a subgroup analysis by treatment, location (cortical/medullary) and a sensitivity analysis by follow-up time.

RESULTS

Sixteen studies were included (a total of 1605 patients) in the quantitative meta-analysis. PVS-SWI were related with a poor functional outcome (RR 1.62, 95% CI 1.25 to 2.10), especially in the patients receiving thrombolysis (RR 2.19, 95% CI 1.53 to 3.15) and an augmented risk of early neurological damage (RR 2.85, 95% CI 2.31 to 3.51). Both cortical and medullary prominent veins were accompanied by a poor functional outcome (RR 1.82, 95% CI 1.30 to 2.56/RR 2.59, 95% CI 1.98 to 3.38). PVS-SWI were not associated with poor functional outcomes when patients were treated conservatively (RR 1.35, 95% CI 0.82 to 2.22), or with an increased risk of hemorrhagic transformation (RR 0.97, 95% CI 0.64 to 1.47).

CONCLUSION

PVS-SWI were related to a poor functional prognosis and an increased risk of early neurological damage. In patients treated conservatively, PVS-SWI were not accompanied by a poor prognosis. PVS-SWI were not associated with an augmented risk of hemorrhagic transformation.

Asymmetrical cortical vein sign predicts early neurological deterioration in acute ischemic stroke patients with severe intracranial arterial stenosis or occlusion

Background

Susceptibility weighted imaging (SWI) provides an approximate assessment of tissue perfusion and shows prominent hypointense cortical veins in the ischemic territory because of the increased concentration of deoxyhemoglobin. We aimed to evaluate whether asymmetrical prominent cortical vein sign (APCVS) on SWI can predict early neurological deterioration (END) in acute ischemic stroke patients with severe intracranial arterial stenosis or occlusion (SIASO).

Methods

One hundred and nine acute ischemic stroke patients with SIASO who underwent SWI were retrospectively recruited. END was defined as an increase in the National Institutes of Health Stroke Scale score ≧2 points despite standard treatment in the first 72 h after admission. The APCVS was defined as more and/or large vessels with greater signal loss than those in the opposite hemisphere on SWI.

Results

Thirty out of the 109 (27.5%) patients developed END. Sixty (55.0%) patients presented with APCVS on SWI. APCVS occurred in 24 (80%) patients with END, whereas it only occurred in 36 (45.6%) patients without END (P = 0.001). Patients with APCVS were more likely to have END (40.0%, vs. 12.2%, P = 0.001) than those without END. Multivariate logistic regression indicated that APCVS (OR = 4.349, 95% C.I. = 1.580–11.970, P = 0.004) was a significant predictor of END in acute ischemic stroke patients with SIASO, adjusted for previous stroke history and acute infarct volume.

Conclusions

In acute ischemic stroke patients with SIASO, the APCVS might be a useful neuroimaging marker for predicting END, which suggests the importance of evaluation of perfusion status.

Asymmetric Deep Medullary Veins in Patients With Occlusion of a Large Cerebral Artery: Association With Cortical Veins, Leptomeningeal Collaterals, and Prognosis

Objective: To explore the relationships of asymmetric deep medullary veins (ADMV) to asymmetric cortical veins (ACV), leptomeningeal collaterals and prognosis in patients with occlusion of a large cerebral artery. Methods: Clinical and imaging data of 56 patients with occlusion of a large cerebral artery were collected and reviewed. We assessed the time delayed between stroke onset and MR imaging (within 24 h of stroke onset), extension of cerebral infarction using the Alberta stroke program early CT score based on diffusion-weighted imaging (ASPECTs). ADMV and ACV were assessed using susceptibility-weighted imaging. The presence of ADMV (ACV) was defined as deep medullary veins (cortical veins) of the affected hemisphere that were greater in number and diameter than in the contralateral hemisphere. To evaluate leptomeningeal collaterals, the hyperintense vessel sign (HVS) was detected using T2 weighted fluid attenuated inversion recovery images. At 90 days, a modified Rankin scale score (mRS) was assessed to evaluate the clinical outcome. Results: Of 56 patients, 27 presented with ADMV. Those patients who presented with and without ADMV differed significantly in HVS and ACV (P < 0.05) but not in time delayed between stroke onset and MR imaging, age, gender, stroke risk factors, baseline NIHSS score, or modified Rankin scale score at 3 months (P > 0.05). Logistic regression analysis found that the presence of ADMV was independently related to HVS and ACV (ACV: OR 95% C.I., 1.287-4.368; HVS: OR 95% C.I., 1.132-4.887). Conclusions: The presence of ADMV on SWI was associated with prominent ACV and good leptomeningeal collateral flow but was not related to prognosis in patients with occlusion of a large cerebral artery.

Susceptibility-weighted imaging in post-treatment evaluation in the early stage in patients with acute ischemic stroke

Objective

This study aimed to investigate the association between abnormal signs on susceptibility-weighted imaging (SWI) and post-treatment outcome in the early stage in patients with acute ischemic stroke.

Methods

Thirty-seven patients with middle cerebral artery territory infarction were recruited. Baseline and 24-hour follow-up magnetic resonance imaging was performed. Pre- and 24-hour post-treatment clinical conditions were assessed with the National Institutes of Health Stroke Scale (NIHSS) score. Prominent vessel sign (PVS) on SWI and infarcted areas on diffusion-weighted imaging (DWI) were assessed using the Alberta Stroke Program Early CT (ASPECT) score system. Susceptibility vessel sign (SVS) was evaluated and recorded. The associations between image abnormalities and clinical scores were analyzed.

Results

PVS was found in 35 patients and SVS in seven patients. The extent of PVS was significantly correlated with the post-treatment DWI ASPECT score (r = 0.79), but not with the post-treatment NIHSS score or the post−pre NIHSS difference score. The presence of SVS was significantly correlated with the post-treatment NIHSS score (r = 0.41).

Conclusion

PVS might be a useful predictor of early imaging prognosis and infarct growth in patients with acute ischemic stroke. SVS is related to a poor early outcome and could be useful for assessing stroke.

Significance of arterial spin labeling perfusion and susceptibility weighted imaging changes in patients with transient ischemic attack: a prospective cohort study

Background

In a prospective cohort of patients with transient ischemic attack (TIA), we investigated usefulness and feasibility of arterial spin labeling (ASL) perfusion and susceptibility weighted imaging (SWI) alone and in combination with standard diffusion weighted (DWI) imaging in subacute diagnostic work-up. We investigated rates of ASL and SWI changes and their potential correlation to lasting infarction 8 weeks after ictus.

Methods

Patients with TIA underwent 3T-MRI including DWI, ASL and SWI within 72 h of symptom onset. We defined lasting infarction as presence of 8-week MRI T2-fluid attenuated inversion recovery (FLAIR) hyperintensity or atrophy in the area of initial DWI-lesion.

Results

We included 116 patients. Diffusion and perfusion together identified more patients with ischemia than either alone (59% vs. 40%, p < 0.0001). The presence of both diffusion and perfusion lesions had the highest rate of 8-week gliosis scars, 65% (p < 0.0001). In white matter, DWI-restriction was the determinant factor for scar development. However, in cortical gray matter half of lesions with perfusion deficit left a scar, while lesions without perfusion change rarely resulted in scars (56% versus 21%, p = 0.03). SWI lesions were rare (6%) and a subset of perfusion lesions. SWI-lesions with DWI-lesions were all located in cortical gray matter and showed high scar rate.

Conclusions

ASL perfusion increased ischemia detection in patients with TIA, and was most useful in conjunction with DWI. ASL was fast, robust and useful in a subacute clinical diagnostic setting. SWI had few positive findings and did not add information.

Trial Registration.

http://www.clinicaltrials.gov. Unique Identifier NCT01531946, prospectively registered February 9, 2012.

Electronic supplementary material

The online version of this article (10.1186/s12880-018-0264-6) contains supplementary material, which is available to authorized users.

Fewer peripheral asymmetrical cortical veins is a predictor of favorable outcome in MCA infarctions with SWI-DWI mismatch

BACKGROUND

Outcome prediction of asymmetrical prominent cortical veins (APCVs) on infarction is still debated and may help in selecting patients for reperfusion treatment.

PURPOSE

To explore the relationship between fewer peripheral APCVs and the outcome in the patients of acute/subacute middle cerebral artery (MCA) infarctions as well as the relationship between this sign and stenosis of ipsilateral MCA.

STUDY TYPE

Retrospective case-control study.

POPULATION

We enrolled 41 patients with MCA acute/subacute infarction. Compared to the low sign of cortical veins of contralateral hemisphere on susceptibility-weighted imaging (SWI), these patients were divided into fewer (n = 28) and prominent APCVs (n = 13) groups.

FIELD STRENGTH/SEQUENCE

3.0T conventional stroke sequences, including T₁ -weighted imaging, T₂ -weighted imaging, fluid-attenuated inversion recovery (FLAIR), diffusion-weighted imaging (DWI) (b = 0 and 1000 s/mm² ), MR angiography (MRA), and SWI.

ASSESSMENT

We explored the relationships between fewer peripheral APCVs sign and clinical outcome, as well as the relationship between this sign and the degree of ipsilateral MCA stenosis.

STATISTICAL TESTS

Fisher's exact analysis, logistical regression, as well as Cohen's kappa coefficient were used for statistical analysis.

RESULTS

Fewer and prominent peripheral APCVs were detected in 28 (56.10%) and 13 (43.90%) patients. In 28 patients with fewer peripheral APCVs, 23 patients (82.14%) had a favorable outcome (modified Rankin Scale [mRS] ≤2), and five patients (17.76%) had an unfavorable outcome (mRS >2) (P = 0.010). In terms of MCA stenosis, the rate of normal and mild to moderate stenosis of MCA in the fewer APCVs group (82.14%) was higher than that in the prominent APCVs group (23.08%) (P < 0.001). More severe stenosis of ipsilateral MCA was found in patients with prominent APCVs group (76.92%) than that of fewer APCVs group (17.86%). The peripheral APCVs was positively correlated with the degree of MCA stenosis (r = 0.538, P < 0.001).

DATA CONCLUSION

Fewer peripheral APCVs may suggest a favorable outcome in unilateral MCA infarction. The patency of ipsilateral MCA may correlate to fewer APCVs and favorable outcome.

LEVEL OF EVIDENCE

3 Technical Efficacy: Stage 5 J. Magn. Reson. Imaging 2018;48:964-970.

Susceptibility-based time-resolved whole-organ and regional tissue oximetry

The magnetism of hemoglobin - being paramagnetic in its deoxy and diamagnetic in its oxy state - offers unique opportunities to probe oxygen metabolism in blood and tissues. The magnetic susceptibility χ of blood scales linearly with blood oxygen saturation, which can be obtained by measuring the magnetic field ΔB of the intravascular MR signal relative to tissue. In contrast to χ, the induced field ΔB is non-local. Therefore, to obtain the intravascular susceptibility Δχ relative to adjoining tissue from the measured ΔB demands solution of an inverse problem. Fortunately, for ellipsoidal structures, to which a straight, cylindrically shaped blood vessel segment conforms, the solution is trivial. The article reviews the principle of MR susceptometry-based blood oximetry. It then discusses applications for quantification of whole-brain oxygen extraction - typically on the basis of a measurement in the superior sagittal sinus - and, in conjunction with total cerebral blood flow, the cerebral metabolic rate of oxygen (CMRO₂ ). By simultaneously measuring flow and venous oxygen saturation (SvO₂ ) a temporal resolution of a few seconds can be achieved, allowing the study of the response to non-steady-state challenges such as volitional apnea. Extensions to regional measurements in smaller cerebral veins are also possible, as well as voxelwise quantification of venous blood saturation in cerebral veins accomplished by quantitative susceptibility mapping (QSM) techniques. Applications of susceptometry-based oximetry to studies of metabolic and degenerative disorders of the brain are reviewed. Lastly, the technique is shown to be applicable to other organ systems such as the extremities using SvO₂ as a dynamic tracer to monitor the kinetics of the microvascular response to induced ischemia. Copyright © 2016 John Wiley & Sons, Ltd.

Evaluation of the role of susceptibility-weighted imaging in thrombolytic therapy for acute ischemic stroke

We inspected low-intensity venous signals and microbleeds in patients with acute ischemic stroke (AIS) using susceptibility-weighted imaging (SWI) before and after administration of within-thrombolytic-time-window thrombolytic therapies, and observed their prognosis and safety, in order to guide individualized thrombolytic therapies. Patients with AIS were divided into groups A or B according to the presence of symmetric or asymmetric veins on SWI, and were re-inspected by SWI after intravenous thrombolysis using recombinant tissue plasminogen activator (rt-PA). The National Institutes of Health stroke scale (NIHSS) score before treatment and at 1-h and 24-h posttreatment in the two groups were 11.9, 7.3, and 7.1 in group A, 12.4, 8.2, and 7.9 in group B, significant difference was detected between the two groups after treatment. The 90-day mortality rate was 0, and the incidences of cerebral microbleeds (CMBs) and symptomatic cerebral hemorrhage (SCH) were 17.6%, and 0% in group A, 25.6% and 0% in group B, respectively. The incidences of CMBs and SCH in group A were lower than those in group B, but the intergroup differences were not statistically significant (P>0.05). The 90-day neurological improvement rates in the two groups were 70.2% and 58.1%, respectively, and group A showed a significantly better prognosis than group B (P<0.05). Thus, low-intensity venous signals in SWI can be used to evaluate a low level of perfusion, post-thrombolytic prognosis, and bleeding indexes, and can therefore be used to guide individualized thrombolytic therapies.

Delay of late-venous phase cortical vein filling in acute ischemic stroke patients: Associations with collateral status

Evaluation of the venous system may be useful in stroke prognostication and patient selection for acute intervention strategies. We report a novel phenomenon, delayed-late venous phase cortical vein filling, observed on dynamic computed tomography angiography obtained using multidetector computed tomography scanner, in acute ischemic stroke patients. The aim of this study was to examine the frequency of delayed-late venous phase cortical vein filling and assess its association to baseline collateral status. Dynamic computed tomography angiography images of acute ischemic stroke patients, being assessed for reperfusion therapy, were prospectively studied. Delayed-late venous phase cortical vein filling was defined by late venous phase opacification of cortical veins despite contrast clearance from contralateral cortical veins on dynamic computed tomography angiography. Time to peak of maximum arterial enhancement was recorded. A total of 117 patients (mean age = 70.6 ± 13.3 years; males = 48%) with hemispheric ischemic stroke who underwent acute dynamic computed tomography angiography were included in the study. Overall, 56 (48%) demonstrated delayed-late venous phase cortical vein filling. Poor collateralization (OR = 13.50; 95% CI = (4.2, 43); p ≤ 0.0001) and longer time to peak of maximum arterial enhancement (OR = 3.2; 95% CI = (1.96, 5.3); p  ≤ 0.0001) were positively associated with delayed-late venous phase cortical vein filling. Delayed-late venous phase cortical vein filling was independently associated with poor baseline collateral status (75% vs. 15%, p ≤ 0.0001; OR = 14.38; 95% CI = (4.33, 47.8); p ≤ 0.0001). Delayed-late venous phase cortical vein filling is frequently seen in patients with acute ischemic stroke and is associated with poor baseline collateralization.

Venous imaging-based biomarkers in acute ischaemic stroke

Vascular neuroimaging plays a decisive role in selecting the best therapy in patients with acute ischaemic stroke. However, compared with the arterial system, the role of veins has not been thoroughly studied. In this review, we present the major venous imaging-based biomarkers in ischaemic stroke. First, the presence of hypodense veins in the monophasic CT angiography ipsilateral to the arterial occlusion. Second, the asymmetry of venous drainage in the pathological cerebral hemisphere on CT and MRI dynamic angiography. Finally, the presence of hypodense veins on T2* -based MRI. From the physiological point of view, the venous imaging-based biomarkers would detect the alteration of brain perfusion (flow), as well as the optimisation of extraction oxygen mechanisms (misery perfusion). Several studies have correlated the venous imaging-based biomarkers with grade of collateral circulation, the ischaemic penumbra and clinical functional outcome. Although venous imaging-based biomarkers still have to be validated, growing evidence highlights a potential complementary role in the acute stroke clinical decision-making process.

Hypointense Vessels Detected by Susceptibility-Weighted Imaging Identifies Tissue at Risk of Infarction in Anterior Circulation Stroke

BACKGROUND AND PURPOSE

The diagnostic value of susceptibility-weighted magnetic resonance imaging of acute stroke patients has shown potential as a surrogate marker of impaired hemodynamics. We investigate the value of asymmetrical hypointense cerebral vessels (HV) for the identification of vessel status and tissue at risk of infarction (TaR).

METHODS

Symmetry of HV was visually rated on SWI data from a well-defined population of acute anterior circulation stroke with onset <24 hours. MRI perfusion data was analyzed and volumes of tissue at risk segmented using a delay threshold of Tmax> 6 seconds. Status of the extra- and intracranial arteries was assessed by ultrasound and MR angiography.

RESULTS

35 patients were included (12 women; median age 69 years, IQR 61-77; median NIHSS at admission 10, IQR 6-20). Asymmetrically distributed HV were detected at the stroke hemisphere in 25 patients (71%). Of those, 12 patients displayed occlusion of the middle cerebral artery, whereas occlusion of the extracranial ICA was detected in 6 patients. TaR was larger, yet not significantly different in patients with asymmetrically HV (mean volume 38.9 ml, SD 52.9 ml) compared to patients showing symmetrical HV (4.2 ml; SD 10.7 ml, p-value 0.081). Significant differences where, however, found after excluding patients with extracranial ICA occlusions (42.9 ml; SD 50.4 ml vs. 4.2 ml, SD 10.8 ml, p-value 0.025).

CONCLUSION

Visual analysis of HV in SWI identifies tissue at risk in patients with anterior circulation stroke. Potentially pre-existing extracranial ICA occlusions leading to prominent HV have to be considered as a confounding factor.

Association of Cortical Vein Filling with Clot Location and Clinical Outcomes in Acute Ischaemic Stroke Patients

Delay in cortical vein filling during the late-venous phase (delayed-LCVF) is characterized by opacification of cerebral veins despite contrast clearance from contralateral veins on dynamic computed tomography angiography (dCTA) in acute ischemic stroke (AIS) patients. The aim of the study was to investigate the associations of delayed-LCVF with clot location, reperfusion status at 24 hours, and 90-days functional outcome in AIS patients who received reperfusion therapy. A prospective cohort of AIS patients treated with intravenous thrombolysis was studied. Groupwise comparison, univariate, and multivariate regression analyses were used to study the association of delayed-LCVF with clot location and clinical outcomes. Of 93 patients (mean age = 72 ± 12 years) with hemispheric AIS included in the study, 46 (49%) demonstrated delayed-LCVF. Patients with delayed-LCVF demonstrated a significantly higher proportion of proximal occlusion (72% vs 13%, P =< 0.0001), and poor reperfusion at 24 hours (41% vs 11%, P = 0.001). The proportion of poor functional outcome at 90 days was not significantly different (22/56 (48%) vs 17/61 (36%), P = 0.297). The appearance of delayed-LCVF on baseline dCTA may be a surrogate for large vessel occlusion, and an early marker for poor 24-hour angiographic reperfusion.

Increased susceptibility of asymmetrically prominent cortical veins correlates with misery perfusion in patients with occlusion of the middle cerebral artery

OBJECTIVES

To evaluate tissue perfusion and venous susceptibility in ischaemic stroke patients as a means to predict clinical status and early prognosis.

METHODS

A retrospective study of 51 ischaemic stroke patients were enrolled in this study. Susceptibility, perfusion and National Institute of Health stroke scale (NIHSS) were compared between patients with and without asymmetrically prominent cortical veins (APCVs). The correlation between susceptibility, perfusion and NIHSS was performed.

RESULTS

Compared to patients without APCVs, the age of patients with APCVs was statistically older (p = 0.017). Patients with APCVs at discharge showed clinical deterioration in their NIHSS. Mean transit time (MTT), time to peak (TTP) and cerebral blood flow (CBF) in the stroke hemisphere were statistically delayed/decreased in patients with and without APCVs (all p < 0.05). In patients with APCVs, the changes in susceptibility positively correlated with increases in MTT and TTP (p < 0.05). Susceptibility and TTP positively correlated and CBF negatively correlated with NIHSS both at admission and discharge (p < 0.05).

CONCLUSIONS

Patients with APCVs have a tendency of deterioration. The presence of APCVs indicates the tissue has increased oxygen extraction fraction. Increased susceptibility from APCVs positively correlated with the delayed MTT and TTP, which reflects the clinical status at admission and predicts an early prognosis.

KEY POINTS

• Patients with and without APCVs have similar misery perfusion. • Patients with APCVs have a tendency of deterioration compared to those without. • The presence of APCVs indicated the tissue has increased oxygen extraction fraction. • Increased susceptibility from APCVs positively correlated with the MTT and TTP. • Increased susceptibility from APCVs reflected the clinical status at admission.

Evaluating the Role of Reduced Oxygen Saturation and Vascular Damage in Traumatic Brain Injury Using Magnetic Resonance Perfusion-Weighted Imaging and Susceptibility-Weighted Imaging and Mapping

The cerebral vasculature, along with neurons and axons, is vulnerable to biomechanical insult during traumatic brain injury (TBI). Trauma-induced vascular injury is still an underinvestigated area in TBI research. Cerebral blood flow and metabolism could be important future treatment targets in neural critical care. Magnetic resonance imaging offers a number of key methods to probe vascular injury and its relationship with traumatic hemorrhage, perfusion deficits, venous blood oxygen saturation changes, and resultant tissue damage. They make it possible to image the hemodynamics of the brain, monitor regional damage, and potentially show changes induced in the brain's function not only acutely but also longitudinally following treatment. These methods have recently been used to show that even mild TBI (mTBI) subjects can have vascular abnormalities, and thus they provide a major step forward in better diagnosing mTBI patients.

A Comparison Study of Single-Echo Susceptibility Weighted Imaging and Combined Multi-Echo Susceptibility Weighted Imaging in Visualizing Asymmetric Medullary Veins in Stroke Patients

Background

Asymmetric medullary veins (AMV) are frequently observed in stroke patients and single-echo susceptibility weighted imaging (SWI_s) is the main technique in detecting AMV. Our study aimed to investigate which echo time (TE) on single-echo susceptibility is the optimal echo for visualizing AMV and to compare the ability in detecting AMV in stroke patients between SWI_s and multi-echo susceptibility weighted imaging (SWI_c).

Materials and Methods

Twenty patients with middle cerebral artery stroke were included. SWI was acquired by using a multi-echo gradient-echo sequence with six echoes ranging from 5 ms to 35.240 ms. Three different echoes of SWI_s including SWI_s1 (TE = 23.144 ms), SWI_s2 (TE = 29.192 ms) and SWI_s3 (TE = 35.240 ms) were reconstructed. SWI_c was averaged using the three echoes of SWI_s. Image quality and venous contrast of medullary veins were compared between SWI_s and SWI_c using peak signal-to-noise ratio (PSNR), mean opinion score (MOS), contrast-to-noise ratio (CNR) and signal-to-noise ratio (SNR). The presence of AMV was evaluated in each SWI_{s (1–3)} and SWI_c.

Results

SWI_s2 had the highest PSNR, MOS and CNR and SWI_s1 had the highest SNR among three different echoes of SWI_s. No significant difference was found in SNR between SWI_s1 and SWI_s2. PSNR, MOS and CNR in SWI_c were significantly increased by 27.9%, 28.2% and 17.2% compared with SWI_s2 and SNR in SWI_c was significantly increased by 32.4% compared with SWI_s1. 55% of patients with AMV were detected in SWI_s2, SWI_s3 and SWI_c, while 50% AMV were found in SWI_s1.

Conclusions

SWI_s using TE around 29ms was optimal in visualizing AMV. SWI_c could improve image quality and venous contrast, but was equal to SWI_s using a relative long TE in evaluating AMV. These results provide the technique basis for further research of AMV in stroke.

Bright and dark vessels on stroke imaging: different sides of the same coin?

PURPOSE

Prominent hypointense cerebral vessels on susceptibility-weighted imaging (SWI) and the hyperintense vessel sign (HVS) on fluid-attenuated inversion recovery (FLAIR) imaging are considered as markers of compromised tissue perfusion in cerebral ischemia. In this study, we aimed to identify the correlation between HVS on FLAIR and hypointense vessels on SWI, and to determine whether these imaging features provide independent prognostic information in patients with ischemic stroke.

METHODS

We retrospectively analyzed consecutive ischemic stroke patients with proximal middle cerebral artery (MCA) occlusion who underwent SWI and FLAIR within 24 h of symptom onset. The presence of hypointense vessels on SWI and hyperintense vessels on FLAIR in >4 of 10 slices encompassing the MCA territory were considered to represent prominent hypoperfusion.

RESULTS

Among 50 patients, 62% had a prominent HVS on FLAIR and 68% had prominent hypointense vessels on SWI. There was a moderate but significant correlation between the number of slices with HVS on FLAIR and prominent hypointense vessels on SWI (r=0.425, P = 0.002). In multivariate analyses, the prominence of hypointense vessels on SWI, but not HVS on FLAIR, was significantly associated with a higher discharge NIHSS score (P = 0.027), mRS score (P = 0.021), and lesion growth (P = 0.050).

CONCLUSION

The significant, albeit moderate, correlation between markers of compromised tissue perfusion on FLAIR and SWI suggests that these imaging features reflect different but interrelated aspects of cerebral hemodynamics during ischemic stroke. Our findings highlight that while HVS on FLAIR denotes the presence of leptomeningeal collaterals, hypointense vessels on SWI signify the sufficiency of cerebral blood flow at the tissue level and are therefore more critical in terms of prognosis.

Predicting Mortality in Patients With "Malignant" Middle Cerebral Artery Infarction Using Susceptibility-Weighted Magnetic Resonance Imaging: Preliminary Findings

To evaluate malignant middle cerebral artery (MCA) infarction (defined as space-occupying edema in more than 50% to 75% of the MCA territory) on magnetic resonance imaging (MRI) with susceptibility-weighted imaging (SWI) sequence and assess the usefulness of SWI findings, diffusion-weighted imaging (DWI) findings, and apparent diffusion coefficient (ADC) as predictors of clinical outcome.Data from 16 patients with large MCA infarction previously admitted to our institution between December 2009 and October 2012 were retrospectively collected and analyzed. Within 7 days after stroke onset, 1 neurologist and 1 neuroradiologist estimated the area of infarction on DWI/ADC and extent of prominent vessel sign (PVS) on SWI images using the Stroke Program Early MR Score (SPEMRS). The PVS on SWI was defined as a local prominence of hypointense vessels with either increased vessel number or diameter in the target area, when compared with the number or diameter of the contralateral MCA territory vessels.Six patients died and 10 survived. Although the DWI/ADC-SPEMRS and clinical profiles were similar between the nonsurvivor and survivor groups, SWI-SPEMRS was significantly lower in the nonsurvivor group (P < 0.001).The area of deoxygenation on SWI in patients with malignant MCA infarction can predict mortality. Lower SWI-SPEMRS is a potentially better predictor of poor outcome than lower DWI-SPEMRS. A larger prospective study is needed to clarify the role of SWI as a therapeutic guide in malignant MCA.

Asymmetry of deep medullary veins on susceptibility weighted MRI in patients with acute MCA stroke is associated with poor outcome

BACKGROUND AND PURPOSE

Due to its sensitivity to deoxyhemoglobin, susceptibility weighted imaging (SWI) enables the visualization of deep medullary veins (DMV) in patients with acute stroke, which are difficult to depict under physiological circumstances. This study assesses the asymmetric appearance of prominent DMV as an independent predictor for stroke severity and outcome.

MATERIALS AND METHODS

SWI of 86 patients with acute middle cerebral artery (MCA) stroke were included. A scoring system from 0 (no visible DMV) to 3 (very prominent DMV) was applied for both hemispheres separately. A difference of scores between ipsi- and contralateral side was defined as asymmetric (AMV+). Occurrence of AMV+ was correlated with the National Institute of Health Stroke Scale (NIHSS) Score on admission and discharge, as well as the modified Rankin Scale (mRS) at discharge. Ordinal regression analysis was used to evaluate NIHSS and mRS as predictors of stroke severity, clinical course of disease and outcome.

RESULTS

55 patients displayed AMV+ while 31 did not show an asymmetry (AMV-). Median NIHSS on admission was 17 (11-21) in the AMV+ group and 9 (5-15) in the AMV- group (p = 0.001). On discharge median NIHSS was 11 (5-20) for AMV+ and 5 (2-14) for AMV- (p = 0.005). The median mRS at discharge was 4 (3-5) in the AMV+ group and 3 (1-4) in AMV- (p = 0.001). Odds ratio was 3.19 (95% CI: 1.24-8.21) for AMV+ to achieve a higher mRS than AMV- (p = 0.016).

CONCLUSION

The asymmetric appearance of DMV on SWI is a fast and easily evaluable parameter for the prediction of stroke severity and can be used as an additional imaging parameter in patients with acute MCA stroke.

Decreased oxygen saturation in asymmetrically prominent cortical veins in patients with cerebral ischemic stroke

Decreased oxygen saturation in asymmetrically prominent cortical veins (APCV) seen in ischemic stroke has been hypothesized to correlate with an increase of de-oxygenated hemoglobin. Our goal is to quantify magnetic susceptibility to define APCV by establishing a cutoff above which the deoxyhemoglobin levels are considered abnormal. A retrospective study was conducted on 26 patients with acute ischemic stroke in one cerebral hemisphere that exhibited APCV with 30 age- and sex-matched healthy controls. Quantitative susceptibility mapping (QSM) was used to calculate the magnetic susceptibility of the cortical veins. A paired t-test was used to compare the susceptibility of the cortical veins in the left and right hemispheres for healthy controls as well as in the contralateral hemisphere for stroke patients with APCV. The change in oxygen saturation in the APCV relative to the contralateral side was calculated after thresholding the susceptibility using the mean plus two standard deviations of the contralateral side for each individual. The thresholded susceptibility value of the APCVs in the stroke hemisphere was 254±48 ppb which was significantly higher (p<0.05) than that in the contralateral hemisphere (123±12 ppb) and in healthy controls (125±8 ppb). There was a decrease of oxygen saturation in the APCV ranging from 16% to 44% relative to the veins of the contralateral hemisphere. In conclusion, APCV seen in SWI correspond to reduced levels of oxygen saturation and these abnormal veins can be identified using a susceptibility threshold on the QSM data.

Asymmetrical cortical vessel sign on susceptibility-weighted imaging: a novel imaging marker for early neurological deterioration and unfavorable prognosis

BACKGROUND AND PURPOSE

Susceptibility-weighted imaging (SWI) is a high spatial resolution technique that can indirectly demonstrate increased cerebral oxygen extraction. Our aim was to assess whether asymmetric cortical vessel sign (ACVS) on SWI could be associated with early neurological deterioration (END) as well as 90-day unfavorable outcome in patients with acute ischaemic stroke.

MATERIALS AND METHODS

Consecutive patients with acute middle cerebral artery (MCA) territory infarction were prospectively enrolled. ACVS was defined as more and/or larger vessels with greater signal loss than those in the opposite hemisphere on minimum intensity projection of SWI. The neurofunctional fluctuation during acute phase as well as 90-day outcomes were assessed. A National Institutes of Health Stroke Scale increment ≥2 points and ≥4 points despite standard treatment in the first 72 h after admission was defined as END2 and END4, respectively.

RESULTS

In all, 572 patients were finally enrolled. ACVS on SWI was present in 39 (6.8%) subjects. Multivariate analysis indicated that ACVS is an independent predictor for END2 [odds ratio (OR) 4.47, 95% confidence interval (CI) 1.99-10.05) and END4 (OR 4.24, 95% CI 1.94-9.23). Furthermore, ACVS also correlates with 90-day unfavorable outcome defined as a modified Rankin Scale score >1 point (OR 2.93, 95% CI 1.15-7.48). Both positive and negative predictive values of ACVS for END2, END4 and 90-day prognosis were reasonable and both could be slightly enhanced as long as patients with contralateral artery stenosis or occlusion were excluded.

CONCLUSION

In patients with MCA territory acute ischaemic stroke, especially in those without contralateral internal carotid artery/MCA stenosis or occlusion, ACVS might be considered as a neuroimaging predictor for END and unfavorable prognosis.

Susceptibility-diffusion mismatch predicts thrombolytic outcomes: a retrospective cohort study

BACKGROUND AND PURPOSE

Asymmetric hypointensity of cerebral veins on susceptibility-weighted imaging has been shown to indirectly reflect tissue hypoxia after cerebral ischemia. We therefore investigated whether patients with prominent asymmetry of the cerebral veins on SWI and a relatively small diffusion-weighted imaging lesion (SWI-DWI mismatch), representing the presence of salvageable tissue, were more likely to benefit from thrombolytic therapy.

MATERIALS AND METHODS

We conducted a retrospective study of the anterior circulation of patients with ischemic stroke with SWI/DWI acquired before thrombolysis. The asymmetry index was defined as the ratio of cerebral vein voxel count between the ischemic and normal hemisphere on the SWI phase map. We defined SWI-DWI mismatch as an asymmetry index score of ≥1.75 with a DWI lesion volume of ≤25 mL. Favorable outcome was defined as modified Rankin Scale 0-2 at 3 months. Univariate and multivariate logistic regression analyses were used to examine the association between the mismatch profile and favorable outcome.

RESULTS

Fifty-four patients undergoing thrombolytic treatment were enrolled in this study. The rate of favorable outcome was significantly higher among patients with baseline SWI-DWI mismatch compared with those without (78% versus 44%; adjusted odds ratio, 6.317; 95% CI, 1.12-35.80; P = .037). Patients with SWI-DWI mismatch were also more likely to have a favorable outcome from reperfusion (91% versus 43%, P = .033) or recanalization (100% versus 40%, P = .013). The accuracy of SWI-DWI mismatch for predicting favorable outcome was higher than that of perfusion-diffusion mismatch (63% versus 48.1%).

CONCLUSIONS

The presence of SWI-DWI mismatch may identify patients with ischemia who would benefit from early reperfusion therapy.