Evaluation of internal carotid artery stenosis with maximum intensity projection of dual source bone and hard plaque removals under dual-energy computed tomographic angiography

Abstract

Objective To evaluate the veracity of maximum intensity projection(MIP)of dual source bone and hard plaque removals under dual-energy computed tomographic angiography(DE-CTA)in diagnosis of stenosis of the internal carotid arteries,and compare these results to those of digital subtraction angiography(DSA).Methods A total of 32 patients suspected as having atherosclerosis in the head and neck,admitted to our hospital from August 2008 to May 2010,were chosen in our study;these patients received DSA before CTA or 1 d to 1 month after CTA.Six anatomical segments were described for each internal carotid artery according to Fischer(1938); ratings were based on a 1-4 scale for MIP under DE-CTA.Lesions were categorized as mild stenosis(0％-49％),moderate stenosis(50％ -69％),severe stenosis(70％-99％)and total stenosis(no flow was detected).Stenosis of internal carotid artery was evaluated based on bone and hard plaque removal MIP images under DE-CTA and DSA.Results Three hundred and eighty-four anatomical segments were divided in all the 32 patients,except for 19 with occlusions and 4 with stent.Imaging quality evaluation of 361 segments indicated that 344 segments(95％)enjoyed scores higher than 3 points and 17 enjoyed 1 point.Mild stenosis,moderate stenosis,severe stenosis and total stenosis were noted in 322,10,12 and 19 segments,respectively.Six segments were noted as having different results under DE-CTA and DSA,with higher stenosis degree under DE-CTA.Conclusion DE-CTA has a high negative predictive value for internal carotid stenosis,by decreasing the influence of bone and calcification on carotid artery. Key words: Internal carotid artery; Dual-energy computed tomographic angiography; Digital subtracted angiography