FLOW-RELATED ANAEROBIC METABOLIC CHANGES IN PATIENTS WITH SEVERE STENOSIS OF THE INTERNAL CAROTID-ARTERY

Background and Purpose We sought to investigate whether the combinatio n of blood flow measurements in the major cerebral arteries and measur ements of cerebral metabolism can provide new insight into the hemodyn amic effect of carotid lesions in patients with severe stenosis (> 70% reduction in diameter) of the internal carotid artery (ICA). Methods Fifty-six patients with unilateral severe stenosis of the ICA and 14 c ontrol subjects underwent MR imaging, H-1 MR spectroscopy, and MR angi ography. Anaerobic metabolic changes were studied by assessing N-acety l aspartate/choline and lactate/N-acetyl aspartate ratios in the sympt omatic and asymptomatic hemispheres. Quantitative Bow was measured in the common carotid arteries (CCAs). the ICAs, the basilar artery, and the middle cerebral arteries (MCAs). Results Blood flow was significan tly decreased in the CCA, ICA, and MCA on the ipsilateral side compare d with the contralateral side. Flow in the basilar artery was increase d, whereas flow in the contralateral MCA was decreased compared with c ontrol subjects. We found a significant correlation between anaerobic metabolic changes and the reduction in blood flow in the CCA, ICA, and MCA on the ipsilateral side. Conclusions This study shows that cerebr al metabolism is less impaired in patients with relatively high Bow in the major cerebral arteries on the ipsilateral side than in patients with relatively low flow on that side. The combination of MR spectrosc opy and MR angiography can be of additional value in the understanding of cerebral hemodynamics and metabolism in patients with vascular dis orders.