Related Experiment Video
Updated: Jun 20, 2026
Diffusion Tensor Magnetic Resonance Imaging in the Analysis of Neurodegenerative Diseases
Published on: July 28, 2013
Presenting Symptoms and Diffusion-Weighted MRI Positivity by Time After Transient Neurologic Events: A Pooled
Koji Tanaka1, Shelagh B Coutts1, Raed A Joundi1
1From the Department of Clinical Neurosciences (K. Tanaka, S.B.C., N.S., E.E.S., A.M.D.), Radiology (S.B.C., E.E.S., A.M.D), Community Health Sciences (S.B.C.), and Hotchikiss Brain Institute (S.B.C., E.E.S., A.M.D.), Cumming School of Medicine, University of Calgary, Calgary, Canada; Rady Faculty of Health Sciences (N.S.), University of Manitoba, Winnipeg, Canada; Division of Neurology (R.A.J.), Hamilton Health Sciences, McMaster University & Population Health Research Institute, Hamilton, Canada; Department of Cerebrovascular Medicine (T.U., T.O., M.K., J.K., K. Toyoda, K.M.), National Cerebral and Cardiovascular Center, Suita, Japan; Stroke Rapid Assessment Unit (A.M.P.), Island Health, Victoria; George & Fay Yee Centre for Healthcare Innovation (R.F.B.), University of Manitoba, Winnipeg; Department of Research and Capacity Building (M.M.B.), Island Health, Victoria; Island Health Regional Health Authority, Division of Medical Sciences (K.V.), University of Victoria, Victoria, Canada.
Background And Objective:
The association between focal vs nonfocal presenting symptom and diffusion-weighted imaging (DWI) positivity in relation to onset-to-imaging time in patients with transient neurologic events remains unclear. We hypothesize that episodes consisting of focal symptoms would have proportionally higher DWI-positive imaging at later onset-to-imaging times.
Methods:
Patients with transient neurologic symptoms and a normal neurologic examination who had DWI in the combined data set of 3 cohort studies were included. We used logistic regression models to evaluate the association between each type of presenting symptom (motor weakness, speech impairment, sensory symptoms, vision loss, diplopia, gait instability, dizziness, headache, presyncope, and amnesia) and DWI positivity after adjusting for clinical variables (age, sex, history of stroke, dyslipidemia, coronary artery disease, atrial fibrillation, symptoms duration [<10, 10-59, ≥60 minutes, or unclear], and study source). We stratified the results by onset-to-imaging time categories (<6 hours, 6-23 hours, and ≥24 hours).
Results:
Of the total 2,411 patients (1,345 male, median age 68 years), DWI-positive lesions were detected in 598 patients (24.8%). The prevalence of DWI positivity was highest in those with motor weakness (34.7%), followed by speech impairment (33.5%). In a multivariable analysis, the presence of motor weakness, speech impairment, and sensory symptoms was associated with DWI positivity, while vision loss and headache were associated with lower odds of DWI positivity, but nevertheless had 13.6% and 15.3% frequency of DWI positive. The odds of being DWI positive varied by onset-to-imaging time categories for motor weakness, with greater odds of being DWI positive at later imaging time (<6 hours: odds ratio [OR] 1.25, 95% confidence interval [CI] 0.84-1.87; 6-23 hours: OR 2.24, 95% CI 1.47-3.42; and ≥24 hours: OR 2.42, 95% CI 1.74-3.36; interaction p = 0.033). Associations of other symptoms with DWI positivity did not vary significantly by time categories.
Discussion:
We found that onset-to-imaging time influences the relationship between motor weakness and DWI positivity in patients with transient neurologic events. Compared with motor, speech, and sensory symptoms, visual or nonfocal symptoms carry a lower but still a substantive association with DWI positivity.
Insights
Transient neurologic events with motor weakness show increased diffusion-weighted imaging (DWI) positivity over time. Focal symptoms like motor weakness are more likely to be DWI-positive, especially with delayed imaging.
Area of Science:
- Neurology
- Radiology
- Clinical Medicine
Background:
- The relationship between presenting symptoms, imaging findings, and timing in transient neurologic events is not fully understood.
- Diffusion-weighted imaging (DWI) is a key tool for detecting acute ischemic changes.
Purpose of the Study:
- To investigate the association between focal versus nonfocal presenting symptoms and DWI positivity.
- To determine the influence of onset-to-imaging time on DWI positivity in transient neurologic events.
Main Methods:
- Analysis of a combined dataset from 3 cohort studies including patients with transient neurologic symptoms and normal neurological exams.
- Logistic regression models were used to assess the association between symptom types and DWI positivity, adjusting for clinical variables.
- Stratification by onset-to-imaging time categories: <6 hours, 6-23 hours, and ≥24 hours.
Main Results:
- DWI-positive lesions were detected in 24.8% of 2,411 patients.
- Motor weakness (34.7%) and speech impairment (33.5%) had the highest prevalence of DWI positivity.
- Motor weakness showed a significant interaction with onset-to-imaging time, with increasing odds of DWI positivity at later imaging times (p=0.033).
Conclusions:
- Onset-to-imaging time significantly influences the association between motor weakness and DWI positivity in transient neurologic events.
- While focal symptoms like motor weakness, speech impairment, and sensory symptoms are more strongly associated with DWI positivity, visual or nonfocal symptoms still show a substantive association.
