Associations of clinical stroke misclassification ('clinical-imaging dissociation') in acute ischemic stroke.
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.
Potter
Gillian
G
Department of Clinical Neurosciences, University of Edinburgh, Western General Hospital, Edinburgh, UK.
Doubal
Fergus
F
Jackson
Caroline
C
Sudlow
Cathie
C
Dennis
Martin
M
Wardlaw
Joanna
J
D000208:Acute Disease; D000368:Aged; D000369:Aged, 80 and over; D001479:Basal Ganglia / Q000098:blood supply / Q000000981:diagnostic imaging; D020520:Brain Infarction / Q000145:classification* / Q000150:complications / Q000175:diagnosis / Q000000981:diagnostic imaging; D002545:Brain Ischemia / Q000175:diagnosis* / Q000000981:diagnostic imaging; D001933:Brain Stem / Q000098:blood supply / Q000000981:diagnostic imaging; D002540:Cerebral Cortex / Q000098:blood supply / Q000000981:diagnostic imaging; D002544:Cerebral Infarction / Q000175:diagnosis / Q000000981:diagnostic imaging; D048909:Diabetes Complications / Q000175:diagnosis / Q000000981:diagnostic imaging; D003937:Diagnosis, Differential; D003951:Diagnostic Errors; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D020243:Infarction, Anterior Cerebral Artery / Q000175:diagnosis / Q000000981:diagnostic imaging; D020762:Infarction, Posterior Cerebral Artery / Q000175:diagnosis / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D009069:Movement Disorders / Q000209:etiology; D011446:Prospective Studies; D012678:Sensation Disorders / Q000209:etiology; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D014057:Tomography, X-Ray Computed