3D-CTAによる頸動脈狭窄症治療後の経過観察  [in Japanese] Postoperative Follow up for Carotid Stenosis with 3D-CT Angiography after CEA/CAS  [in Japanese]

We previously reported the usefulness of three-dimensional (3D) CT angiography for perioperative evaluation of carotid endarterectomy (CEA) to avoid several complications in conventional angiography, which was reported to be 1.2% in ACAS. We describe here the utility of 3D-CTA in follow-up at an outpatient clinic made possible by the clear and accurate view provided by 3D-CTA. Forty-five of 64 consecutive CEA cases were examined with 3D-CTA (mean age 67.7 y/o, male : female=12 : 4) and 16 consecutive CAS cases (mean age 72.6 y/o, male : female=39 : 6) were examined with 3D-CTA preoperatively, 1-week, 3 to 6-months and 1 to 2 years after surgical intervention, reconstructing into volume rendering (VR), maximum intensity projection (MIP) and multiplanar reconstruction (MPR) images. Three-dimensional CT angiography visualized subtle changes such as small dents caused by vascular tourniquets used in operation, which mostly diminished in 1 year. Dilatation of external carotid artery was shown along with amelioration of internal carotid artery, though 19.4% of external carotid arteries demonstrated transient narrowing or occlusion. Restenosis after CEA occurred in 4 cases (6.3%), 2 of which were subjected to CAS. The course of restenoses as well as the state after stenting were clearly delineated with 3D-CTA. Sagittal and axial MPR images were useful in confirmation for lumen. Though DSA remains the gold standard in some facilities in follow-up studies after CEA, its use is declining due to the complications it presents and to the development of other diagnostic modalities. Duplex US is a handy, non-invasive, real-time technique but is limited due to its operator dependency and low resolution. MR angiography is promising, though it is still being developed. Three-D CTA with a high-performance workstation provides detailed images with satisfactory information for postoperative follow-up studies in outpatient clinics, though it also presents the problems of X-ray exploration and allergic reaction to contrast media.