Automated perfusion imaging for the evaluation of transient ischemic attack

Area of Science:

• Neuroradiology
• Medical Imaging
• Neurology

Background:

• Diffusion-weighted imaging (DWI) is a standard for transient ischemic attack (TIA) evaluation.
• Perfusion imaging techniques can enhance MRI's diagnostic yield in TIA cases.
• Automated bolus perfusion (TMax, MTT) and arterial spin labeling (ASL) are advanced perfusion methods.

Purpose of the Study:

• To compare the efficacy of automated bolus perfusion (TMax and MTT) and ASL sequences in detecting ischemic lesions in patients with suspected TIA.
• To assess the added value of perfusion imaging beyond DWI in TIA diagnosis.

Main Methods:

• Consecutive patients with suspected TIA underwent multimodal MRI within 36 hours of symptom onset.
• Two blinded raters evaluated ischemic lesions on DWI, TMax, MTT, and ASL.
• Prevalence of lesions and interrater agreement were calculated.

Main Results:

• 27% of patients were DWI-positive; an additional 15% were positive on perfusion imaging (ASL, TMax, or MTT) but DWI-negative.
• Automated TMax identified significantly more ischemic lesions (20) than MTT (7).
• Interrater agreement was good for DWI, TMax, and ASL, but only fair for MTT.

Conclusions:

• Automated TMax perfusion is more sensitive than MTT for detecting ischemic lesions in TIA patients.
• Both ASL and automated TMax perfusion significantly increase the diagnostic yield of MRI for TIA.
• Multimodal MRI including DWI and advanced perfusion techniques is valuable for TIA evaluation.