Abstract Details

Magnetic resonance DWI findings are a sign of stroke even in patients with TIAs.

We undertook a cohort study of adult patients with a NIH Stroke Scale ≤ 3 admitted to three emergency departments’ (EDs’) observation units for an accelerated diagnostic protocol for suspected TIA or stroke. Clinical and imaging results were recorded prospectively. Non-mydriatic fundus photographs were obtained and reviewed for retinal microvascular findings, defined as retinal hemorrhages, cotton wool spots, retinal emboli or occlusions, hard exudates, or microaneurysms. Retinal vessels were measured. Central retinal artery and vein equivalents (CRAE & CRVE) using Knudson’s method were calculated as were arteriovenous ratios (AVR).  Predictive models were developed using fast-and-frugal trees.

167/395 patients enrolled who had photographs of sufficient quality for all relevant measurements were included (median age: 54 years (interquartile range [IQR]: 45–61); 96 (57%) women; 102 (61%) black; 34 (20%) with DWI positive scans).  The fast-and-frugal tree with the highest balanced accuracy (62%) predicted DWI positivity using smaller AVR (<0.63) and CRAE (<160 mm), larger CRVE (>237 mm), and the presence of cotton wool spots, retinal hemorrhages, or focal arteriolar narrowing; it had 77% specificity, but only 47% sensitivity. 

Retinal microvascular findings and vessel diameters are moderately associated with DWI positivity among patients with suspected TIA but have relatively low sensitivity (proportion of DWI positives correctly identified).