MedWire News: More ischemic lesions are detectable in patients with suspected transient ischemic attack (TIA) with combined diffusion-weighted imaging (DWI) and perfusion-weighted imaging (PWI) than with either modality alone, report researchers.

“Future studies should compare various analysis techniques to clarify how PWI acquisition and analysis methods affect the overall yield in TIA patients,” say Gregory Albers (Stanford University Medical Center, California, USA) and team.

The researchers performed DWI and PWI in 43 patients who presented within 48 hours of symptoms suggesting a TIA. Of these, 33% had a lesion on PWI and 35% on DWI. Lesions were visible with both PWI and DWI in 16% of patients, but 16% had lesions on PWI only.

As reported in the journal Neurology, using both techniques resulted in lesions being detected in 51% of patients.

Detection of a lesion with either technique was five to seven times more likely in patients imaged within 12 hours of onset than in those examined later.

Two independent raters examined all brain images, while blinded to clinical findings. The raters agreed on the presence 98% of DWI lesions, compared with 81% of PWI lesions.

But Albers et al note that lesions were usually found in the hemisphere predicted by clinical symptoms. This occurred for 93% of DWI lesions and 86% of PWI lesions.

“Therefore, we propose that detection of either a DWI or PWI lesion in the setting of symptoms compatible with a TIA provides objective confirmation that brain ischemic is the likely etiology for the patient’s acute symptoms as well as evidence for the involved vascular territory,” they conclude.

Free abstract