||Background and Purposes: Maintaining sufficient blood flow to the brain consistently is important to keep normal brain function. As we know, ischemic stroke is a common disease caused by acute impairment of focal cerebral perfusion due to vessel occlusion. However, attention has recently focused on the adverse effect of chronic cerebral hypoperfusion on brain structural changes and cognitive function. Early neurologic deterioration (END) is frequently observed and related to poor functional outcome in acute ischemic stroke, Cell adhesion molecules (CAMs) have been reported to involve the pathogenesis of cerebral ischemia, however, the association with cerebral perfusion has not been evaluated. In this thesis, Arterial spin labeling (ASL) MRI, a new imaging technique, was used to assess the cerebral perfusion. There were several purposes in this study. (1) To understand the association between perfusion-diffusion (PWI-DWI) mismatch and END in acute stroke. (2) To understand the association between chronic cerebral perfusion and brain structural change in mild cognitive impairment (MCI). (3) To evaluate the impact of CAMs on perfusion-diffusion mismatch in acute stroke and cerebral hypoperfusion in MCI.|
Material and methods: The study separately enrolled acute stroke patients and patients with MCI. In acute stroke, ASL perfusion MRI was performed within 48 h of symptoms onset to detect PWI-DWI mismatch. National Institutes of Health Stroke Scale (NIHSS) and Barthel index were used to score neurologic deficit and functional impairment at admission, one week and one month after stroke. END was defined as an increase of 2 or more points in NIHSS within one week after stroke onset. Plasma levels of CAMs including VCAM-1, ICAM-1and E-selectin were measured at admission and one week after symptoms onset. In patients with MCI, ASL perfusion was used to quantitate regional cerebral perfusion. Cognitive function was assessed and plasma levels of CAMs were measured at enrollment.
Result: 120 patients with acute stroke in cerebral hemisphere were enrolled. There were 65 patients with lacunar stroke and 55 patients with thromboembolic stroke. Patients with PWI-DWI mismatch had higher risk for END in thromboembolic infarct. Higher level of VCAM-1 was independently associated with PWI-DWI mismatch and END in thromboembolic infarct. 110 patients with MCI were enrolled. Cerebral hypoperfusion was associated with cognitive impairment, medial temporal lobe atrophy and increase white matter lesions. The level of VCAM-1 was significant inversely associated with cerebral cortical perfusion especially posterior parietal lobe even after adjusted for cerebrovascular risk factors.
Conclusion: The study suggested the importance of cerebral perfusion as the PWI-DWI mismatch associated with END in acute stroke and chronic cerebral hypoperfusion associated with medial temporal lobe atrophy, white matter lesions and cognitive impairment in MCI. CAMs especially VCAM-1 played a role in acute and chronic cerebral hypoperfusion.