Computed Tomography versus Magnetic Resonance Imaging Diffusion-Weighted Imaging in the Diagnosis of Acute Cerebral Infarction: A Comparative Observational Study

Abstract

Background: Acute cerebral infarction (ACI) represents a neurological emergency where time-sensitive revascularization is paramount. The choice of initial neuroimaging modality critically influences therapeutic decision-making. While non-contrast computed tomography (CT) is widely used for its rapidity and accessibility, magnetic resonance imaging with diffusion-weighted imaging (MRI-DWI) offers superior sensitivity for early ischemia. Objective: This study aimed to conduct a rigorous, head-to-head comparison of the diagnostic efficacy of CT and MRI-DWI in a well-defined cohort of patients with ACI, with a specific focus on lesion detection rates across different brain locations and sizes. Methods: A prospective observational study was conducted involving 100 patients with clinical suspicion of lacunar infarction. All participants underwent both non-contrast CT and MRI-DWI examinations within 6 hours of symptom onset. Images were independently evaluated by two blinded radiologists. Diagnostic accuracy, lesion localization detection rates (frontal, parietal, temporal, occipital lobes, basal ganglia, thalamus, internal capsule, cerebellum, brainstem), and lesion size detection rates (<5 mm, ≥5 mm) were calculated and compared using chi-square tests, with a significance level set at P < 0.01. Results: The study cohort had a median age of 64 years, with 63% male participants. MRI-DWI demonstrated a diagnostic accuracy of 100%, significantly outperforming CT's accuracy of 85% (P < 0.01). Statistically significant differences in detection rates favoring MRI-DWI were observed across all specified cerebral locations, most notably in the brainstem (P = 0.01). Furthermore, MRI-DWI was significantly superior in detecting infarcts smaller than 5 mm (P < 0.01). Conclusion: MRI-DWI is unequivocally more sensitive than non-contrast CT in the early diagnosis of ACI, particularly for small lesions and those located in the posterior fossa. These findings strongly suggest that MRI-DWI should be considered the first-line imaging modality when available and feasible, as it provides critical information that can optimize patient triage and treatment strategies.