Background: Accurate and timely neuroimaging is essential for distinguishing hemorrhagic from ischemic strokes in emergency settings. While CT is effective in detecting cerebral hemorrhage, it has limited sensitivity for early ischemia. Low-field MRI technology presents a promising alternative. Recently, a new Hematoma Enhanced Inversion Recovery (HEIR) sequence based on 0.23-Tesla MRI was developed, enabling fast and accurate stroke diagnosis according to previous single-center cohorts. However, its accuracy against CT in larger-scale cohorts remains to be proven. Purpose: To compare the performance of 0.23-T MRI versus CT in diagnosing acute cerebral hemorrhage at Emergency Departments within 24 hours of symptom onset. Materials and Methods: A prospective, multicenter study was performed at 6 Emergency Departments between January and July 2024. Patients with suspected stroke symptoms who underwent both CT and 0.23-T MRI within 24 hours of symptom onset were included. The 0.23-T MRI protocol consisted of diffusion-weighted imaging (DWI), fluid-attenuated inversion recovery (FLAIR), and HEIR sequences, with a total scan time of 7.2 minutes (Figure 1). Four readers independently evaluated the CT and 0.23-T MRI images. Diagnostic accuracy for stroke was compared between CT and 0.23-T MRI, with the final diagnosis based on all clinical and imaging evidence available serving as the reference. Results: A total of 1,013 participants were included in the study. Among all patients, 0.23-T MRI correctly identified 101 of 102 hemorrhagic strokes, missing only one small lesion (1 mm in diameter). CT also identified 101 of 102 hemorrhagic strokes, missing one case of chronic hematoma detected on SWI of 3T MRI. Both CT and 0.23-T MRI demonstrated 99.0% sensitivity, 100.0% specificity, and 99.9% accuracy in detecting cerebral hemorrhage (Figure 2). Moreover, 0.23-T MRI demonstrated a 2.5-fold more acute ischemic lesion detection compared to CT (358 0.23-T MRI positive vs. 142 CT positive (Figure 3). Conclusion: With a 7.2-minute protocol, 0.23-T MRI may be as accurate as CT for detecting cerebral hemorrhage within 24 hours of symptom onset, and it identified more acute ischemic strokes than CT in emergency settings. These results highlight the value of 0.23-Tesla MRI as an expedited, reliable screening modality for reperfusion therapy in emergency stroke care.
Xie et al. (2026) studied this question.