Gadolinium Enhancement in Intracranial Atherosclerotic Plaque and Ischemic Stroke: A Systematic Review and Meta-Analysis

Abstract

Background: Gadolinium 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 results: We 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.

Conclusions: Intracranial 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.

Keywords: cerebral infarction; culprit artery; enhancement gadolinium; ischemic stroke; magnetic resonance imaging; plaque; vessel wall imaging.

© 2016 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley Blackwell.

Figures

Figure 1

Magnetic resonance images showing an enhancing atherosclerotic plaque in the right middle cerebral artery in a symptomatic patient who had suffered a recent right cerebral hemispheric acute ischemic stroke. A mixture of acute and chronic infarction involving the right periventricular and frontal subcortical regions is seen in the diffusion‐weighted image (DWI); the plaque is shown by an arrow in the time‐of‐flight (TOF) image, and a cross section at the most stenotic site is shown in T2, T1, and contrast‐enhanced (CE) T1 images (red asterisks: lumen).

Figure 2

Study selection flow diagram.

Figure 3

Forest plot of the association between magnetic resonance imaging–determined plaque contrast enhancement (CE) and acute ischemic stroke. The meta‐analysis was calculated using a random‐effects model, with the pooled odds ratio (OR) shown in the forest plot. Each square represents the point estimate of any given study's effect size. The size of the squares is proportional to the inverse of the variance of the estimate, while the horizontal lines represent each study's 95% CIs. The diamond represents the pooled estimate with the width of the diamond representing the pooled 95% CI.

Figure 4

Funnel plot to evaluate for publication bias. Individual study effect sizes expressed as odds ratios are shown on the x‐axis and each study's standard error is shown on the y‐axis. Larger and more precise studies are plotted at the top, near the combined (pooled) odds ratio, whereas smaller and less precise studies will show a wider distribution below. If there is no publication bias, the studies would be expected to be symmetrically distributed on both sides of the pooled odds ratio line. In the case of publication bias, the funnel plot may be asymmetrical, since the absence of studies would distort the distribution on the scatter plot.