Background: The cortical vessel signs on susceptibility-weighted MRI (SWI) has been known for reflecting oxygen demand in ischemic brain. In large arterial steno-occlusive disease of ischemic stroke, evaluating regional cerebrovascular reservoir (rCVR) capacity is important to predict future stroke risk. However, it is practically difficult to perform all of the studies such as digital subtraction angiography (DSA), Diamox challenging SPECT study for the assessment of perfusion status and rCVR in acute setting. We selected patients who had undergone those methods and evaluated the associations among the collateral pattern, perfusion status and SWI pattern.
Methods: From a cohort of patients consecutively admitted for stroke or transient ischemic attack (TIA), we selected patients with DSA-proven unilateral large artery steno-occlusive lesion. Cerebral angiogram was graded systematically in a blinded fashion for collateral flow, using ASITN/SIR grading system. We also evaluated rCVR by Diamox SPECT and the cortical vessel signs (CVS) on SWI were classified as normal, mild, moderate and prominent compared with opposite side. Demographic and clinical variables, initial NIHSS score and modified Rankin scale (mRS) scores at discharge were collected. We divided these patients in two groups according to rCVR capacity and compared clinical and imaging status.
Results: A total of 100 patients were selected. Men were 64 (64%) and mean age was 66.1 (range of 34 to 88). Sixty-three patients had ICA steno-occlusive (32 with occlusion), 35 had MCA steno-occlusive lesions (17 with occlusion) and remaining 2 had tandem lesions. In Diamox SPECT, 34 patients (34%) showed preserved rCVR. Patients with preserved rCVR more had stenotic lesions (p=0.003) and good collateral pattern (p=0.026), while patients with reduced rCVR more had higher grade CVS pattern (p=0.018).
Conclusion: Cortical vessel signs on susceptibility-weighted image have an association with regional cerebrovascular reservoir capacity. And this snapshot image would be a useful tool in the real world of clinical practice in evaluating cerebrovascular perfusion status. But longer follow up in much larger populations are needed.