How much would performing diffusion-weighted imaging for all transient ischemic attacks increase MRI utilization?
OBJECTIVE
The American Heart Association recently redefined TIA to exclude patients with infarction on neuroimaging. Given its advantages, MRI/diffusion-weighted imaging (DWI) was recommended as the preferred imaging modality. We determined how frequently MRI/DWI was performed for TIA and ascertained the proportion of clinically defined TIA patients who had ischemic lesions on DWI in our community in 2005.


METHODS
All clinically defined TIA cases among residents of a 5-county region around Cincinnati who presented to emergency departments were identified during 2005. Demographics and medical history, whether MRI/DWI was performed, and DWI findings were recorded. Generalized estimating equations were used to compare groups to account for the design of the study and multiple events per patient.


RESULTS
Of 834 TIA events in 799 patients, 323 events (40%) had MRI/DWI performed. Patients who had MRI/DWI were younger (mean, 66 vs 70 years; P=0.03), had less severe prestroke disability (baseline modified Rankin Scale score, 0; 44% vs 34%; P=0.02), were less likely to have previous stroke or TIA (42% vs 56%; P=0.002), and were less likely to have atrial fibrillation (10% vs 16%; P=0.01). Of the 323 events with DWI, 51 (15%) had evidence of acute infarction. Patients with positive DWI were older (75 vs 64 years; P=0.0001) and more likely to have atrial fibrillation (21% vs 7%; P=0.002).


CONCLUSIONS
Performing MRI/DWI on all clinically defined TIA patients in our community would reveal more cases of actual infarction but would more than double current use. Future studies should assess whether MRI/DWI is warranted for all TIA patients.
Adeoye
Opeolu
O
Departments of Emergency Medicine and Neurosurgery, University of Cincinnati Medical Center, Cincinnati, OH 45267-0525, USA. opeolu.adeoye@uc.edu
Heitsch
Laura
L
Moomaw
Charles J
CJ
Alwell
Kathleen
K
Khoury
Jane
J
Woo
Daniel
D
Flaherty
Matthew L
ML
Ferioli
Simona
S
Khatri
Pooja
P
Broderick
Joseph P
JP
Kissela
Brett M
BM
Kleindorfer
Dawn
D
D000368:Aged; D001281:Atrial Fibrillation / Q000175:diagnosis*; D001921:Brain / Q000473:pathology*; D020520:Brain Infarction / Q000175:diagnosis*; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D005260:Female; D006801:Humans; D002546:Ischemic Attack, Transient / Q000175:diagnosis*; D008297:Male; D008875:Middle Aged
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