Abstract

This study aimed to assess the diagnostic yield of follow‑up diffusion‑weighted magnetic resonance imaging (DWI‑MRI) in emergency department patients with suspected acute ischemic stroke who had an initial negative scan, and to identify associated risk factors. In this retrospective cross‑sectional analysis, we reviewed records of patients presenting between January 2018 and January 2023 who underwent two DWI‑MRI scans for suspected stroke. Inclusion required an initial scan without acute ischemic lesions and a follow‑up scan within 48 hours. Demographics, symptoms, comorbidities, laboratory data, and imaging intervals were analyzed. Among 171 included patients (mean age 66.0 ± 14.7 years; 58.5% female), follow‑up DWI‑MRI revealed new ischemic lesions in 25 cases (14.6%). Patients with positive follow‑up imaging were significantly older (p = 0.047) and more frequently had hyperlipidemia (12.0% vs. 2.1%; p = 0.041). In multivariate analysis, hyperlipidemia remained an independent predictor of positive findings (OR = 7.434, 95% CI: 1.369–40.357, p = 0.020), whereas age did not retain significance. Approximately one in seven patients with suspected ischemic stroke and an initially normal DWI‑MRI show detectable infarction on early follow‑up imaging. Hyperlipidemia is a strong independent risk factor for such delayed‑appearing lesions, suggesting that repeat MRI should be considered in high‑risk patients, particularly those with dyslipidemia, even after an initial negative scan.

Key words: Emergency department, ischemic stroke, magnetic resonance imaging