Background and Purpose:
We developed the MRA collateral map derived from dynamic MR angiography and grading methods with significant linear association with functional outcomes of patients with acute ischemic stroke (AIS). This study is to verify the value of the MRA collateral map for predicting tissue outcome and penumbra in patients with AIS.
Materials and Methods:
From a prospectively maintained registry, patients with AIS due to occlusion or stenosis of the unilateral ICA and/or M1 MCA within 8 hours of symptom onset were included. The collateral-perfusion grading based on the MRA collateral map was estimated using 6-scale MAC. Changes of infarct area were divided into two groups with and without infarct growth (IG
+
and IG
-
). Areas of baseline DWI lesion, Tmax > 6s, and decreased collateral-perfusion on each phases of the MRA collateral map, and infarct lesion on follow-up image were compared by visual assessment.
Results:
One hundred thirty-five patients, including 85 males (mean age, 69 years old), were included. Shorter onset-to-door times (OR=1.04, 95% CI=1.01-1.08) and successful early reperfusion (OR=0.19, 95% CI=0.05-0.66) were independently associated with IG
-
in multivariate analysis. In subgroup analysis, good collateral-perfusion status was associated with IG
-
(OR=0.30, 95% CI=0.10-0.91). In IG
+
group, the infarction grew within hypoperfused area on the phase of the MRA collateral map immediately before the phase that matches the baseline DWI lesion. There was no infarct growth beyond hypoperfused area on the capillary phase of the MRA collateral map in both IG
+
and IG
-
groups. The area of Tmax > 6s matched with the hypoperfused area on capillary phase of the MRA collateral map in 83% of patients.
Conclusion:
In this study, tissue fate in AIS was dependent on early reperfusion. In case of unsuccessful early reperfusion, it was associated with collateral-perfusion status. We suggest that the extent of penumbra can be estimated by the MRA collateral map.
Dynamic MR angiography (MRA) of spinal vascular diseases at 3T
