Clinically confirmed acute ischemic stroke with negative diffusion-weighted imaging: Clinical and imaging features

Abstract

Objective To investigate the clinical and imaging features in patients with clinically confirmed acute ischemic stroke and negative diffusion-weighted imaging (DWI). Methods The clinical and imaging data in patients with clinically confirmed acute ischemic stroke and initial negative DWI were collected retrospectively. According to the repeat DWI findings, they were divided into either a persistent-negative DWI group or a false-negative DWI group. The demographics, and data of clinical and imaging at baseline between the 2 groups were compared, and the causes of the initial negative DWI were analyzed. Results A total of 15 patients with clinically confirmed acute ischemic stroke and initial negative DWI were enrolled, including 9 in the persistent-negative DWI group (9/15, 60.0%) and 6 in the false-negative DWI group (6/15, 40.0%), and 8 with minor stroke (National Institute of Health Stroke Scale score ≤3; 8/15, 53.3%). The time from onset to admission ranged from 1 to 48 h. The time from onset to initial DWI examination ranged from 5 to 65 h. The time from onset to repeat DWI ranged from 38 to 190 h. There were no significant differences in demographics, and data of clinical and imaging at baseline between the 2 groups. In 6 patients with false-negative DWI findings, 5 were posterior circulation stroke (5/6, 83.3%) and 1 was anterior circulation stroke (1/6, 16.7%); 1 might have a second infarct, 1 might be associated with shorter examination time (5 h after onset), 1 was associated with not reaching the diffusion limited threshold and the influence of MRI artifact before symptom aggravation, and the remaining 3 might be associated with smaller lesions and locating in the posterior circulation. The causes of 9 patients with persistent-negative DWI findings were unknown. Conclusions There were no significant differences in features of clinical and imaging at baseline between persistent-negative and false-negative DWI findings. False-negative DWI findings in acute ischemic stroke can be mainly seen in patients with posterior circulation stroke and minor stroke. Key words: Stroke; Brain Ischemia; Magnetic Resonance Imaging; Diffusion Magnetic Resonance Imaging; Time Factors