The Application of MR Perfusion-weighted Imaging in Patients with ICA/MCA Stenosis or Occlusion

Objective To investigate the diagnostic value of MR perfusion-weighted imaging (PWI) in patients with unilateral ICA/MCA chronic high-grade stenos is or occlusion and evaluate the relationship between findings of PWI and degree of ICA/MCA stenosis.Materials and Methods PWI was performed on 90 patients with unilateral ICA(62)/MCA(28) high-grade stenosis or occlusion. The cerebral perfusion parameters such as rCBF, rCBV, rMTT and TTP were calculated, and the qualitative and quantitative analysis were carried out on the occluded side and compared with contralateral hemisphere. 62 patients with unilateral ICA and 28 patients with MCA high-grade stenosis or occlusion were divided into two groups: high-grade stenosis and occlusion respectively. The relationship between the cerebral perfusion findings and the degree of stenosis of arteries was analyzed.Results The abnormal perfusion findings were depicted in 90 patients with ICA/MCA chronic high-grade stenosis or occlusion. The abnormal findings of PWI were divided into three stages: 31 patients of stage one, with TTP and rMTT delayed, rCBF and rCBV normal; 41 patients of stage two, with TTP and rMTT delayed, rCBF normal and rCBV slightly increased; 18 patients of stage three, with TTP and rMTT delayed, rCBF and rCBV slightly decreased. The values of rCBV, rMTT and TTP of abnormal regions were statistically significant difference among the three stages compared with contralateral sides (P0.01). There was no significant difference in rCBF among three stages of PWI (P0.05), but there was statistically significant difference in rCBV、rMTT、TTP among three stages of PWI (P0.01). There was no significant correlation between the findings of PWI and the degree of ICA/MCA stenosis. However, the values of TTP and rMTT were higher in patients with unilateral ICA/MCA occlusion than those in patients with stenosis (P0.01). Conclusion PWI can demonstrate the abnormal hemodynamic changes of brain in patients with unilateral ICA/MCA high-grade stenosis or occlusion and provide valuable diagnostic and therapeutic information individually, and degree of ICA/MCA stenosis can not predict hemodynamic changes of brain.