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Published on: September 20, 2015
Focal Hypoperfusion on Baseline Perfusion-Weighted MRI and the Risk of Subsequent Cerebrovascular Events in Patients
Sofiya Shamailova1, Luiz Dalla Vecchia1, Elias Auer1,2
1Department of Neurology, Inselspital, Bern University Hospital, and University of Bern, Switzerland.
Background And Objectives:
While MRI is known to be crucial for TIA workup, the benefit of perfusion-weighted imaging (PWI) is underexplored. We aimed to assess the association between focal hypoperfusion on baseline PWI MRI and the long-term incidence of subsequent acute ischemic stroke (AIS) after TIA.
Methods:
Consecutive patients with TIA who underwent baseline PWI MRI as part of their emergency consultation between January 2015 and December 2019 were retrospectively identified. For study inclusion, both a time-based (symptom duration <24 hours) and an imaging-based (no signs of ischemia on diffusion-weighted imaging) TIA definition were applied. Long-term incidences of AIS after TIA were identified based on follow-up reports. Associations between focal hypoperfusion and subsequent AIS were assessed using Cox regression models adjusted for predefined predictors of stroke occurrence including symptomatic extracranial or intracranial stenosis. In subgroup analyses, we aimed to determine effects of focal hypoperfusion within vs outside the expected TIA territory, defined as a brain region potentially correlating with TIA symptoms.
Results:
Of 1,359 eligible patients with TIA, 1,075 with PWI MRI (79%) were included (median age 70 years, 46% female). Focal hypoperfusion was identified in 211 patients (20%); in 116 of 211 (55%), hypoperfusion occurred within the expected TIA territory. The median time from symptom onset to imaging was 233 minutes (interquartile range [IQR] 131-632) for patients with focal hypoperfusion vs 229 minutes [IQR 140-441] for patients without (p = 0.42). Focal hypoperfusion was associated with a higher incidence of AIS (adjusted hazard ratio [aHR] 2.13; 95% CI 1.19-3.80). While this was observed for focal hypoperfusion within the expected TIA territory (aHR 3.95; 95% CI 2.05-7.60), there was no such association in case of focal hypoperfusion outside the expected TIA territory (aHR 0.72; 95% CI 0.25-2.03).
Discussion:
Focal hypoperfusion on acute PWI MRI was found in 1 in 5 patients with TIA. It was associated with a higher incidence of AIS during long-term follow-up, especially when within the expected TIA territory. Further research is needed to clarify the predictive value of focal hypoperfusion in relation to the incidence of AIS after TIA and to explore potential therapeutic implications.
Insights
Focal hypoperfusion on perfusion-weighted imaging (PWI) MRI in patients with transient ischemic attack (TIA) is linked to a higher risk of subsequent acute ischemic stroke (AIS). This association is particularly strong when hypoperfusion occurs within the TIA
Area of Science:
- Neurology
- Radiology
- Stroke Medicine
Background:
- Transient ischemic attack (TIA) is a critical warning sign for subsequent acute ischemic stroke (AIS).
- Magnetic Resonance Imaging (MRI) is vital for TIA workup, but the role of perfusion-weighted imaging (PWI) remains underexplored.
- Identifying predictors of recurrent stroke after TIA is crucial for timely intervention.
Purpose of the Study:
- To assess the association between focal hypoperfusion on baseline PWI MRI and the long-term incidence of AIS after TIA.
- To investigate whether the location of hypoperfusion (within or outside the TIA territory) influences the risk of subsequent AIS.
- To evaluate the predictive value of PWI findings in TIA patients.
Main Methods:
- Retrospective analysis of consecutive TIA patients who underwent baseline PWI MRI.
- Inclusion criteria: time-based (<24 hours symptom duration) and imaging-based (no ischemia on DWI) TIA definition.
- Cox regression models were used to assess the association between focal hypoperfusion and subsequent AIS, adjusting for stroke predictors.
Main Results:
- Focal hypoperfusion was identified in 20% of 1,075 TIA patients.
- Focal hypoperfusion was associated with a significantly higher incidence of AIS (aHR 2.13).
- Hypoperfusion within the expected TIA territory showed a stronger association with subsequent AIS (aHR 3.95), while hypoperfusion outside this territory did not (aHR 0.72).
Conclusions:
- Focal hypoperfusion on acute PWI MRI is a significant predictor of long-term AIS risk after TIA.
- The location of hypoperfusion is critical, with findings within the TIA territory indicating a higher risk.
- Further research is warranted to clarify the predictive value and explore therapeutic implications of PWI findings in TIA management.
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