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Updated: May 23, 2026
Integrated Photoacoustic, Ultrasound, and Angiographic Tomography (PAUSAT) for NonInvasive Whole-Brain Imaging of Ischemic Stroke
Published on: June 2, 2023
Automated perfusion imaging for the evaluation of transient ischemic attack
Jonathan T Kleinman1, Greg Zaharchuk, Michael Mlynash
1Department of Neurology and Neurological Sciences, Stanford Stroke Center, 780 Welch Road, Suite 205, Palo Alto, CA 94304, USA.
Background And Purpose:
Diffusion-weighted imaging (DWI) is recommended for the evaluation of transient ischemic attack. Perfusion imaging can increase the yield of MRI in transient ischemic attack. We evaluated automated bolus perfusion (the time when the residue function reaches its maximum [TMax] and mean transit time [MTT]) and arterial spin labeling (ASL) sequences for the detection of ischemic lesions in patients with transient ischemic attack.
Methods:
We enrolled consecutive patients evaluated for suspicion of acute transient ischemic attack by multimodal MRI within 36 hours of symptom onset. Two independent raters assessed the presence and location of ischemic lesions blinded to the clinical presentation. The prevalence of ischemic lesions and the interrater agreement were 1,410 assessed.
Results:
From January 2010 to 2011, 93 patients were enrolled and 90 underwent perfusion imaging (69 bolus perfusion and 76 ASL). Overall, 25 of 93 patients (27%) were DWI-positive and 14 (15%) were perfusion-positive but DWI-negative (ASL n=9; TMax n=9; MTT n=2). MTT revealed an ischemic lesion in fewer patients than TMax (7 versus 20, P=0.004). Raters agreed on 89% of diffusion-weighted imaging cases, 89% of TMax, 87% o10f010 MTT, and 90% of ASL cases. The interrater agreement was good for DWI, TMax, and ASL (κ=0.73, 0.72, and 0.74, respectively) and fair for MTT (κ=0.43). Diffusion and/or perfusion were positive in 39 of 69 (57%) patients with a discharge diagnosis of possible ischemic event.
Conclusions:
Our results suggest that in patients referred for suspicion of transient ischemic attack, automated TMax is more sensitive than MTT, and both ASL and TMax increase the yield of MRI for the detection of ischemic lesions.
Insights
Diffusion-weighted imaging (DWI) and perfusion imaging increase MRI yield for transient ischemic attack (TIA) detection. Automated TMax perfusion is more sensitive than Mean Transit Time (MTT), with both ASL and TMax improving lesion detection in TIA patients.
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.
