Background: In a prospective cohort of patients with transient ischemic attack (TIA), we investigated usefulness and feasibility of arterial spin labeling (ASL) perfusion and susceptibility weighted imaging (SWI) alone and in combination with standard diffusion weighted (DWI) imaging in subacute diagnostic work-up. We investigated rates of ASL and SWI changes and their potential correlation to lasting infarction 8 weeks after ictus.
Methods: Patients with TIA underwent 3T-MRI including DWI, ASL and SWI within 72 h of symptom onset. We defined lasting infarction as presence of 8-week MRI T2-fluid attenuated inversion recovery (FLAIR) hyperintensity or atrophy in the area of initial DWI-lesion.
Results: We included 116 patients. Diffusion and perfusion together identified more patients with ischemia than either alone (59% vs. 40%, p < 0.0001). The presence of both diffusion and perfusion lesions had the highest rate of 8-week gliosis scars, 65% (p < 0.0001). In white matter, DWI-restriction was the determinant factor for scar development. However, in cortical gray matter half of lesions with perfusion deficit left a scar, while lesions without perfusion change rarely resulted in scars (56% versus 21%, p = 0.03). SWI lesions were rare (6%) and a subset of perfusion lesions. SWI-lesions with DWI-lesions were all located in cortical gray matter and showed high scar rate.
Conclusions: ASL perfusion increased ischemia detection in patients with TIA, and was most useful in conjunction with DWI. ASL was fast, robust and useful in a subacute clinical diagnostic setting. SWI had few positive findings and did not add information.
Trial registration: http://www.clinicaltrials.gov . Unique Identifier NCT01531946 , prospectively registered February 9, 2012.
Keywords: Arterial spin labeling; Cerebral cortex; Transient ischemic attack.