Three-Dimensional Reconstruction Of MSCTA And Advanced Vessel Analysis In Evaluation Of Extracranial Internal Carotid Arterial Stenosis

PURPOSETo determine the usefulness of MSCTA for evaluation of extracranial internal carotid atherosclerosis.MATERIALS AND METHODSIn 21 patients, 42 carotid arteries were examined with conventional angiog-raphy and MSCTA (GE Lightspeed Qx/I Extra). For CT angiography, the scanning coverage was from aortic arch to sella turcica. Helical scanning (120KV, 250 ~320Ma, 20cm field of view, 1. 25mm thickness, 1. 875 pitch, 1. 25mm reconstructional interval) was started 17 ~22s after injection of nonionic contrast medium at a rate of 3.5ml/s by using an auto - power injector.Original CT data were transferred to workstation (Advantage Workstation 4. 1 ) for reconstruction and were displayed on advanced vessel analysis ( AVA) , volume rendered (VR) and maximum intensity projection (MIP) images. The quality of CT images and the degree of calcified plaques were evaluated. The ability of AVA, MIP and VR in assessment of the degree of severity of internal carotid arterial stenosis was compared with conventional angiograpy which is considered as a standard. The ability for demonstration of plague morphology, plague ulceration and tendom stenosis was also compared between MSCTA and conventional angiography.The interobserver agreement on measurement of the percentage of stenosis on MIP and VR images and on conventional angiograms was calculated by using k values. The correlation between the three separated CT reconstructions and conventional angiography was evaluated by using Spearman rank correlation a-nalysis. We also estimated the agreement of stenosis severity categorization be-tween three CT imaging techniques and conventional angiography by using k values. At last, the sensitivity and specificity of AVA, MIP and VR in detection of severe stenosis were evaluated. A P value less than 0.05 was considered statistically significant in all tests.