Abstract
This study is aimed to evaluate the proficiency of emergency physicians in identifying ischemic strokes via diffusion-weighted magnetic resonance imaging (DW-MRI), and to determine the inter-rater agreement between emergency department (ED) residents and radiologists. The suspected ischemic stroke patients undergoing DW-MRI and not the candidates for thrombolytic therapy were eligible for the study. Diffusion MRI images were evaluated by the on-duty senior ED residents having two or more years in residency program, and a radiologist. Prior to the study, an instructor from radiology department delivered 2-hour theoretical and 2-hour practical lectures to ED physicians on the evaluation of diffusion MRI. A total of 604 patients were included in the study wherein 145 patients (24%) were detected with ischemic areas. The parietal lobe was the most prevalent ischemic area according to ED physicians’ and radiologist’s findings. ED residents and the radiologist had different interpretations for 54 patients. ED physicians ascribed 15 (3.4%) ischemic stroke patients as normal and 39 (23.1%) normal patients as stroke. ED physicians had 89.7% sensitivity (95% confidence interval (CI): 84% to 94%) and 91.5% specificity (95% CI: 89% to 94%) in diagnosing ischemic stroke. A good inter-rater agreement was found between ED physicians and the radiologist with kappa value of 0.77 (95% CI: 0.71 to 0.83). ED physicians have better success rate in interpreting DW-MRI to detect ischemic stroke in non-candidate cases of thrombolytic therapy (cases whose National Institutes of Health Stroke Skale (NIHSS) score is not appropriate, symptom onset exceeds 4.5 hours, and thrombolytic administration is contraindicated). There is a good inter-rater agreement between ED physicians and radiologist.