Diagnostic Accuracy of 640-Slice Mdct in Evaluating In-Stent Restenosis of Coronary Artery

Cardiac disease is the number two-killer in Taiwan in the last three years. In 2008, there were 15,726 deaths due to cardiac disease, which constitutes 11.05% of all deaths in Taiwan. Coronary artery disease (CAD) is a major socioeconomic issue due to its high health care expenditure. The treatment choices of CAD include medical treatment, percutaneous coronary intervention and coronary artery bypass grafting (CABG). Balloon angioplasty and coronary stent implantation have emerged as the leading treatment for coronary artery stenosis, offering a less invasive procedure and shorter hospitalization period. However, the limitation of angioplasty is the possibility of in-stent restenosis (ISR) mainly due to intimal fibroproliferative response. ISR may occur in 5-25% of cases 6 to 9 months after implantation of metallic stent. Thus early detection and early treatment of ISR is a critical issue for optimal medical care. Conventional invasive coronary angiography (ICA) has been a gold standard in assessing CAD, but it is invasive and expensive. Non-invasive multidetector CT (MDCT) has been playing a promising role in diagnosing CAD. For 64-slice MDCT, an analysis indicated a pooled sensitivity of 99% and a specificity of 93% based on a per-patient analysis. Every month, the 2nd session of Department of Cardiology in our hospital performs around 45 cases of percutaneous coronary stent implantation, and 25 patients with coronary stent implantation undergo ICA to assess the possibility of ISR. Thus there are around 300 ICAs to assess coronary stent each year. Several studies reported a sensitivity of 92-97% and a specificity of 81-95% in detecting ISR by using 64-slice MDCT. However, the positive predictive value has been reported to be as low as 47.1-54% due to inadequate resolution, overlapping of stents, or motion artifacts. To our knowledge, this is the first proposal that attempts to assess the diagnostic accuracy of 640-slice MDCT in evaluating suspected coronary ISR. We plan to perform 200 cases within two years. ICA and 640-slice MDCT will be performed in all patients within one month. Using ICA as a golden standard, this study will evaluate the sensitivity, specificity, accuracy, positive predictive value and negative predictive value of 640-slice MDCT in detecting coronary ISR. Comparing with 64-slice MDCT, 640-slice MDCT has the advantages of larger detector width (160 mm vs 32 mm), shorter cardiac scanning time (0.35 sec vs 9 sec), less effective radiation dose (4-5 mSv vs 16-20 mSv), less motion artifact and usage of less amount of contrast medium by one-thirds.

Project ID:PC10001-1128
External Project ID:NSC99-2314-B182-037-MY2