Associations of Clinical Stroke Misclassification (‘Clinical-Imaging Dissociation’) in Acute Ischemic Stroke

Abstract

Background: Up to 20% of lacunar infarcts are clinically misdiagnosed as cortical infarcts and vice versa. The reasons for this discrepancy are unclear. We assessed clinical and imaging features which might explain this ‘clinical-imaging dissociation’ (C-ID). Methods: Patients with an acute stroke syndrome (cortical or lacunar) underwent magnetic resonance imaging including diffusion-weighted imaging (DWI). We recorded DWI-positive infarcts and proximity to cortex for small subcortical infarcts. We examined factors associated with C-ID. Results: 137 patients with a mild cortical or lacunar syndrome had an acute ischemic lesion on DWI. Of these, 21/93 (23%) with a cortical syndrome had an acute lacunar infarct and 7/44 (16%) with a lacunar syndrome had an acute cortical infarct. From 72 patients with an acute lacunar infarct on DWI, lesion proximity to cortex (odds ratio (OR) 14.5, 95% confidence interval (CI) 1.61–130.1), left hemisphere location (OR 8.95, 95% CI 1.23–64.99) and diabetes (OR 17.1, 95% CI 1.49–196.16) predicted C-ID. On multivariate analysis of all 137 patients, C-ID was associated with diabetes (OR 7.12, 95% CI 1.86–27.2). Conclusions: C-ID occurs in a fifth of patients with mild stroke. Lacunar infarcts lying close to cortex are more likely to cause cortical symptoms. Diabetes is associated with any clinical-imaging mismatch. Stroke misclassification which can arise with clinical classification alone should be minimized in research by verification with high-sensitivity imaging.

A Systematic Review of Dynamic Cerebral and Peripheral Endothelial Function in Lacunar Stroke Versus Controls

“…Studies that used suboptimal imaging, either insensitive or applied too late after the acute symptoms, may have confused up to 20% of lacunar strokes as cortical strokes and vice versa. 47 It was often unclear if the investigators were blind to study group; unblinding may increase investigator bias. The endothelial function data were not adjusted for potential confounders such as blood pressure, diabetes, hypercholesterolemia, smoking, prior stroke, white matter hyperintensities on imaging, old infarcts or hemorrhages on imaging, age, or medication.…”

Wide Variation in Definition, Detection, and Description of Lacunar Lesions on Imaging

“…The clinical value of the lacunar hypothesis has been questioned by some, because as many as 20% of lacunar strokes may be caused by pathologies other than a small, deep infarct, including hemorrhage and cortical infarction. 3,4 Lacunar infarcts are often defined in stroke registries by a combination of clinical features (with or without inclusion of risk factors) and imaging findings, 5 and controversy exists as to whether emboli are an important cause of lacunar infarction. 6 -8 On brain imaging, lacunar lesions form part of a spectrum of features of cerebral small-vessel disease (SVD), which often have overlapping appearances.…”

“…10 Identification of old lacunar lesions was best for cavitated lesions, but because only a fifth of symptomatic lacunar infarcts cavitate, cavitation is an unreliable marker for prior lacunar infarction. 9 Variation in imaging definitions and heterogeneity in the reporting of other lacunar stroke-related features may be contributing to ongoing controversies in lacunar stroke research, 6 -8,21-25 for example, bias in clinical classification systems 20,26 ; misclassification of cortical as lacunar stroke, based on clinical symptoms alone 3,4 ; suboptimal detection of acute lacunar infarcts; difficulties in differentiating old lacunes from EPVSs; and limited information on previous neurologic symptoms.…”

Carotid Intima-Media Thickness and Cerebrovascular Disease in Community-Dwelling Older People Without Stroke

“…1 It is unclear, however, whether CIMT is a stronger risk factor for large vessel disease (LVD) or small vessel disease (SVD). 2,3 Some of this apparent discrepancy may be because of incorrect classification of cortical stroke as lacunar stroke 4 or because CIMT, LVD, and SVD are all associated with hypertension. 5 The most common imaging biomarker of SVD is white matter lesion (WML) load, but the evidence relating CIMT to WML load is inconsistent.…”