Examination timing and lesion patterns in diffusion-weighted magnetic resonance imaging of patients with classically defined transient ischemic attack

Background: This study investigated factors associated with the presence of acute ischemic lesions after transient ischemic attack (TIA), using diffusion-weighted imaging (DWI) data from a multicenter retrospective, observational study.

Methods: Of the 464 patients admitted to 13 stroke centers in Japan within 7 days after TIA onset, 458 patients underwent a DWI examination in this registry. Patients were divided into those with acute ischemic lesions and those without. We analyzed associations between DWI lesions and baseline characteristics, including age, sex, comorbidities, large artery atherosclerosis (LAA), type and duration of symptoms, the presence of multiple occurrences of TIA within 90 days before hospital visits (multiple TIAs) and the time from symptom onset to DWI examination (time-to-DWI).

Results: Among the 458 patients (291 men, 68.4±13.2 years old), 374 (81.7%) underwent a DWI examination within the initial 24 hours after the symptom onset. DWI lesions were found in 96 patients (21.0%), and divided into a single lesion (56 patients, 12.2%) or multiple lesions (40 patients, 8.7%). The presence of DWI lesions had an association with male sex (odds ratio [OR] 1.84; 95% confidence interval [CI] 1.07-3.29), time-to-DWI longer than 24 hours (OR 2.96; CI 1.57-5.52), and intracranial LAA (OR 1.99; CI 1.02-3.79). The presence of a single DWI lesion had an association with atrial fibrillation (OR 2.70; CI 1.41-5.03), and multiple DWI lesions did with time-to-DWI longer than 24 hours (OR 6.20; CI 2.60-15.20), multiple TIAs (OR 3.04; CI 1.35-6.76), intracranial LAA (OR 3.63; CI 1.44-8.89), and extracranial LAA (OR 3.53; CI 1.08-10.78).

Conclusions: Acute ischemic lesions on DWI were associated with time-to-DWI and LAA in patients with classically defined TIA. Additionally, we identified some differences in relating factors between patients with single and multiple DWI lesions. These results indicate that time-to-DWI and DWI lesion pattern may be important for the diagnosis and management of TIA.