BackgroundGadolinium enhancement on high‐resolution magnetic resonance imaging (MRI) has been proposed as a marker of inflammation and instability in intracranial atherosclerotic plaque. We performed a systematic review and meta‐analysis to summarize the association between intracranial atherosclerotic plaque enhancement and acute ischemic stroke.Methods and ResultsWe searched the medical literature to identify studies of patients undergoing intracranial vessel wall MRI for evaluation of intracranial atherosclerotic plaque. We recorded study data and assessed study quality, with disagreements in data extraction resolved by a third reader. A random‐effects odds ratio was used to assess whether, in any given patient, cerebral infarction was more likely in the vascular territory supplied by an artery with MRI‐detected plaque enhancement as compared to territory supplied by an artery without enhancement. We calculated between‐study heterogeneity using the Cochrane Q test and publication bias using the Begg‐Mazumdar test. Eight articles published between 2011 and 2015 met inclusion criteria. These studies provided information about plaque enhancement characteristics from 295 arteries in 330 patients. We found a significant positive relationship between MRI enhancement and cerebral infarction in the same vascular territory, with a random effects odds ratio of 10.8 (95% CI 4.1–28.1, P<0.001). No significant heterogeneity (Q=11.08, P=0.14) or publication bias (P=0.80) was present.ConclusionsIntracranial plaque enhancement on high‐resolution vessel wall MRI is strongly associated with ischemic stroke. Evaluation for plaque enhancement on MRI may be a useful test to improve diagnostic yield in patients with ischemic strokes of undetermined etiology.
Background Studies have shown that pericoronary artery inflammation can be accurately detected via increased attenuation on computed tomography. Our purpose was to evaluate the association between pericarotid inflammation, measured by density of carotid perivascular fat on computed tomography angiography, with stroke and transient ischemic attack. Methods and Results We screened computed tomography angiography examinations for patients with unilateral internal carotid artery ( ICA ) stenosis ≥50% to 99%. A blinded neuroradiologist placed regions‐of‐interest in the pericarotid fat on the slice showing maximal stenosis. Two‐sample t tests were performed to assess between‐subject differences in mean Hounsfield Units in carotid perivascular fat between symptomatic and asymptomatic patients. Paired t tests were used to assess within‐subject differences in mean Hounsfield Units between stenotic versus nonstenotic ICA s in a given patient. We included 94 patients, including 42 symptomatic and 52 asymptomatic patients. In the between‐subject analysis of stenotic ICA s, we found symptomatic patients had higher mean pericarotid fat density compared with asymptomatic patients (−66.2±19.2 versus −77.1±20.4, P =0.009). When comparing nonstenotic ICA s, there was no significant difference between pericarotid fat density in symptomatic compared with asymptomatic patients (−81.0±13.3 versus −85.3±18.0: P =0.198). Within‐subject comparison showed statistically significant increased density in stenotic ICA versus nonstenotic ICA with mean Hounsfield Units difference of 11.1 ( P <0.0001). Conclusions We found increased density, a surrogate marker for perivascular inflammation, in the fat surrounding ICA s ipsilateral to stroke or transient ischemic attack compared with asymptomatic ICA s. Our findings suggest that inflammation associated with culprit carotid plaques extends beyond the vessel lumen and can be identified using simple methods on computed tomography angiography imaging.
BACKGROUND: CTA is a widely available imaging examination that may allow the evaluation of high-risk carotid plaque features.
Background and Purpose: We aim to examine effects of collateral status and post-thrombectomy reperfusion on final infarct distribution and early functional outcome in patients with anterior circulation large vessel occlusion ischemic stroke. Methods: Patients with large vessel occlusion who underwent endovascular intervention were included in this study. All patients had baseline computed tomography angiography and follow-up magnetic resonance imaging. Collateral status was graded according to the criteria proposed by Miteff et al and reperfusion was assessed using the modified Thrombolysis in Cerebral Infarction (mTICI) system. We applied a multivariate voxel-wise general linear model to correlate the distribution of final infarction with collateral status and degree of reperfusion. Early favorable outcome was defined as a discharge modified Rankin Scale score ≤2. Results: Of the 283 patients included, 129 (46%) had good, 97 (34%) had moderate, and 57 (20%) had poor collateral status. Successful reperfusion (mTICI 2b/3) was achieved in 206 (73%) patients. Poor collateral status was associated with infarction of middle cerebral artery border zones, whereas worse reperfusion (mTICI scores 0–2a) was associated with infarction of middle cerebral artery territory deep white matter tracts and the posterior limb of the internal capsule. In multivariate regression models, both mTICI ( P <0.001) and collateral status ( P <0.001) were among independent predictors of final infarct volumes. However, mTICI ( P <0.001), but not collateral status ( P =0.058), predicted favorable outcome at discharge. Conclusions: In this cohort of patients with large vessel occlusion stroke, both the collateral status and endovascular reperfusion were strongly associated with middle cerebral artery territory final infarct volumes. Our findings suggesting that baseline collateral status predominantly affected middle cerebral artery border zones infarction, whereas higher mTICI preserved deep white matter and internal capsule from infarction; may explain why reperfusion success—but not collateral status—was among the independent predictors of favorable outcome at discharge. Infarction of the lentiform nuclei was observed regardless of collateral status or reperfusion success.
Background Concerns have arisen about the long-term health effects of repeated gadolinium injections in multiple sclerosis (MS) patients and the incomplete characterization of MS lesion pathophysiology that results from relying on enhancement characteristics alone. Purpose To perform a systematic review and meta-analysis analyzing whether non-contrast MRI biomarkers can distinguish between enhancing and non-enhancing brain MS lesions. Data Sources Ovid MEDLINE, Ovid Embase, and the Cochrane Database from inception to August 2016. Study Selection We included 37 journal articles on 985 MS patients who had MRI in which T1-weighted post-contrast sequences were compared to non-contrast sequences obtained during the same MRI examination using ROI analysis of individual MS lesions. Data Analysis We performed random-effects meta-analyses comparing the standard mean difference of each MRI metric taken from enhancing versus non-enhancing lesions. Data Synthesis DTI-based FA values are significantly different between enhancing and non-enhancing lesions (P=0.02), with enhancing lesions showing decreased FA compared to non-enhancing lesions. Of the other most frequently studied MRI biomarkers (MD, MTR, or ADC) none were significantly different (P-values of 0.30, 0.47, and 0.19. respectively) between enhancing and non-enhancing lesions. Of the limited studies providing diagnostic accuracy measures, gradient echo-based QSM had the best performance in discriminating between enhancing and non-enhancing MS lesions. Limitations MRI techniques and patient characteristics were variable across studies. Most studies did not provide diagnostic accuracy measures. All imaging metrics were not studied in all 37 studies. Conclusions Non-contrast MRI techniques, such as DTI-based FA, can assess MS lesion acuity without gadolinium.
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