The Diagnostic Accuracy of the 64-slice Multi-detector CT Coronary Angiography for the Assessment of Coronary Artery Stenosis in Symptomatic Patients

PURPOSE: We evaluated the diagnostic accuracy of a 64-slice multi-detector CT (MDCT) coronary angiography against a conventional coronary angiography (CCA) for the detection of significant stenosis (> or =50% lumen diameter narrowing). MATERIALS AND METHODS: Sixty-four patients underwent a MDCT and a subsequent CCA to evaluate the presence of atypical chest pain or suspected coronary artery disease (CAD). A MDCT angiography was performed using a 64-slice MDCT-scanner (Sensation 64, slice collimation 32x0.6 mm). The coronary artery segments were classified according to a 15-segment model. The sensitivity, specificity, and diagnostic accuracy of the 64-slice MDCT for the detection or exclusion of significant CAD were calculated on a per-segment and per-patient basis. RESULTS: Fifty-nine of the 64 (92%) coronary CT angiograms were of diagnostic image quality with 93.5% (809 of 865) of the coronary segments assessable by CT angiography. One-hundred two (12.6%) segments showed significant stenosis by CCA. Stenosis of 50% or greater was detected by sensitivity, specificity, accuracy, positive predictive valve, and negative predictive value on a per segment basis (89%, 99%, 97%, 90%, and 98%, respectively) and a per-patient basis (96%, 69%, 90%, 92%, and 82%, respectively). CONCLUSION: The 64-slice MDCT coronary angiography demonstrated a high diagnostic accuracy for both the per-segment and per-patient analyses for this symptomatic patient group.

Coronary CT Angiography: Focus on a New Algorithm as Diagnostic Tool in Routine Clinical Practice

Various invasive and non-invasive imaging techniques have been used for the diagnosis of coronary artery disease. Despite several limitations, coronary CTA may soon emerge as the initial diagnostic modality of choice for patients with suspected coronary artery disease. However, in routine clinical practice, the role of coronary CTA is not clearly defined even though promising diagnostic accuracy has been demonstrated compared with that of the other non-invasive tests. Herein, we suggest a new paradigm for coronary CTA as an emerging diagnostic tool in routine clinical practice on the basis of our experience and published data.

ECG-gated CT Angiography for the Assessment of Coronary bypass Graft Patency: the Influence of Heart Rate, Type of bypass Graft, Target Vessel and Surgical Technique on the Diagnostic Accuracy

PURPOSE: We wanted to evaluate the accuracy of using ECG-gated CT angiography (CTA) for the assessment of coronary bypass graft patency. MATERIALS AND METHODS: This study included 48 patients who underwent both CTA and conventional angiography to evaluate coronary bypass graft patency. CTA was performed with a 16-detector row multislice CT scanner. We calculated the sensitivity and specificity of CTA to detect occlusion of bypass graft that was equal to or greater than 50% of the expected diameter. Conventional angiography served as a gold standard. A total 160 grafts were evaluated. The diagnostic accuracy was evaluated according to a variety of factors (heart rate, types of bypass graft, target vessel, and surgical techniques). RESULTS: The overall sensitivity, specificity and accuracy of CTA were 83.9%, 95.4% and 93.1%, respectively. There was no significant statistical difference for each factor according to Fisher's exact test. Although the grafts anastomosed to the left circumflex arterial branches and a high heart rate showed a statistically significant high risk of misdiagnosis on the simple logistic regression test, a high heart rate was the only significant factor on the multiple logistic regression test (odds, 5.9). CONCLUSION: CTA provides for good noninvasive evaluation of the coronary bypass graft patency. The heart rate and the anastomosed vessel are factors that can influence the accuracy.

16-Slice Multi-Detector Row CT Coronary Angiography: Image Quality and Optimization of the Image Reconstruction Window

PURPOSE: The purpose of this experiment is to investigate the image quality of CT coronary angiography using a 16-slice multi-detector row CT and to determine the optimal image reconstruction window. MATERIALS AND METHODS: CT coronary angiography was obtained in 36 nonsymptomatic volunteers using a 16-slice multi-detector row CT (SOMATOM Sensation, Siemens Medical System). The mean heart rates were 70 beats per minute (bpm) or less in 18 persons and more than 70 bpm in 18 persons. Eleven data sets were obtained for each patient (reconstructed at 30-80% of the cardiac cycle with an increment of 5%). Image quality of the eight coronary segments [left main coronary artery (LM), proximal and middle segments of left anterior descending artery (p-LAD, m-LAD) and left circumflex coronary artery (p-LCx, m-LCx) and proximal, middle and distal segments of right coronary artery (p-RCA, m-RCA, d-RCA)] was assessed. RESULTS: The optimal reconstruction windows in the cardiac cycle for the best image quality were 60-70% for the segments of the LM, LAD, and LC arteries in two groups (bpm70) and 55-65% (bpm70) for the segments of the RCA. On the best dataset for each coronary segment, the following diagnostic image quality was achieved in the two groups: LM: 100%, 83%; p-LAD: 100%, 88%; m-LAD: 100%, 72%; p-LCx: 100%, 72%; m-LCx: 100%, 72%; p-RCA: 94%, 72%; m-RCA: 61%, 50%; d-RCA: 100%, 88%. CONCLUSION: The 16 slice multi-detector row CT scan provided visualization of the coronary arteries with high resolution. Especially in the group with a mean heart rate of 70 bpm or less, all the coronary segments except the RCA showed diagnostic image quality. Optimal image quality was achieved with a 60-70% trigger delay for all coronary arterial segments, but the best images of RCA were achieved in the earlier cardiac phase in the patients with a mean heart rate of more than 70 bpm.

Coronary Angiography with Multidetector row Computed Tomography: Part II - Clinical Aspects

An application of the multi-detector computed tomography (MDCT) for cardiac imaging is the non-invasive CT angiographic assessment of the cardiac morphology and the coronary arteries. The most important application is for the non-invasive diagnosis of coronary artery disease, and this includes assessment of coronary artery anomaly and stenosis, the evaluation of non-calcified atherosclerotic plaque and the follow-up examinations after stent deployment and bypass surgery. In the study, we have illustrated a variety of diseases of the coronay artery by using MDCT. These may facilitate the understanding of MDCT features of coronary artery lesions.

Coronary Angiography with Multidetector row Computed Tomography: Part I - Technical Aspects

Various invasive and non-invasive imaging techniques have been used for the diagnosis of cardiac disease. The recently introduced multidetector row CT (MDCT) shows rapid scan speed, high temporal resolution and large volume coverage in a single breath-hold. MDCT opens a new horizon for cardiac imaging because noninvasive coronary artery imaging has become feasible using MDCT. In this article, we illustrate the technical aspects of coronary CT angiography using MDCT.

Accuracy of Three-dimensional Coronary Arteriography by Electron-Beam Tomography

PURPOSE: To evaluate the diagnostic accuracy of non-invasive coronary angiography by electron beam tomography(EBT) for the depiction of coronary artery stenosis, as compared with conventional coronary angiography. MATERIALS AND METHODS: In 20 patients with no history of coronary artery disease, EBT (Imatron C-150) study was performed with EKG-gating. Forty images were obtained in each patient from the pulmonary trunk to the cardiac base at 80% R-R interval, and data were reconstructed into a three-dimensional coronary angiography. The interval between conventional coronary arteriograpy and EBT was less than 30 (mean, 9) days. Coronary arteries were divided into seven segments, and stenosis was defined as a narrowing of the luminal diameter of the coronary artery of more than 50 %. The results of EBT and of conventional angiography were compared for diagnostic accuracy. RESULTS: Conventional argiography revealed significant stenosis of the coronary artery in 12 of the 20 patients, while the use of three-dimensional coronary angiography by EBT revealed this in 16. The sensitivity and specificity of EBT were relatively high in the depiction of stenosis in the proximal left anterior descending (LAD), left circumflex (LCx), and right coronary artery (RCA) and middle LAD, but low sensitivity in the middle LCx and RCA. In the left main coronary artery, sensitivity was 50%. The sensitivity, specificity, accuracy, and positive and negative predictive values for the depiction of coronary artery stenosis with three-dimensional coronary arteriography by EBT were 79%, 95 %, 93 %, 71%, and 97 %, respectively. CONCLUSION: Three-dimensional coronary angiography by EBT is a non-invasive diagnostic modality for the depiction of proximal epicardial coronary artery stenosis and appears to be useful for excluding the probability of ischemic heart disease in a selected patient group.

Distribution of Coronary Calcium Score in Healthy Middle-aged Korean

PURPOSE: To determine the prevalence and degree of CAC (coronary artery calcification) in appearently healthy middle-aged Koreans, and the relation of CAC to risk factors for atherosclerosis. MATERIALS AND METHODS: A total of 289 apparently healthy personnel at Yonsei University (male: 170, female: 119, age: mean(SD=54.9 +/-7.1 years) underwent EBT (electron bean tomography). The risk factors for atherosclerosis, which included diabetes mellitus, hypertension, smoking, a family history of precocious onset, obesity, hyperlipidemia, and high intraperitoneal fat, were scrutinized. One hundred and sixty-eight subjects (58 % ) had at least one risk factor. The CAC score was calculated for all subjects and for each coronary artery separately and was then analyzed by age and sex and in relation to the risk factors. RESULTS: The prevalence of CAC was 40% in men and 18.5% in women (mean score: 29.7 vs. 9.9). The number of individuals who had one, two, or more than two risk factors was 141, 41, and 19, respectively. The number of risk factors and the prevalence and score of CAC were significantly correlated (p=0.01, 0.02 respectively). The number of individuals with no risk factor, with without CAC, was 58(20.1%) and 103(35.6% ) , respectively, while the number with some risk factor, with or without CAC, was 38(13.1%) and 90(31.1%), respectively. The CAC score was significantly higher in the presence of hypertension, low HDL, or obesity (p=0.001, 0.049, and 0.068, respectively). Smoking appeared to have a borderline effect on the calcium score (p=0.118). CONCLUSION: This study should provide useful information for interpreting CAC scores and establishing a treatment strategy for Koreans. The comparison of our results with other studies will enable a better understanding of the process and risk factors of atherosclerosis in Koreans.

Utility of Quantification of Coronary Artery Calcification Using Spiral CT

PURPOSE: To evaluate the utility of quantification of coronary artery calcification using spiral CT. MATERIALS AND METHODS: Spiral CT scans of the heart were obtained in 25 patients with coronary artery disease diagnosed by coronary angiography and in six controls without coronary artery disease. Spiral CT was performedwith 3 mm collimation at 3 mm/sec table speed and the obtained volume data of the heart was reconstructed at 2 mm intervals. Total calcium scores of the 30 contiguous slices of the proximal coronary artery were calculated basedon the areas and peak density. Two groups were compared for total scores and sensitivity, and specificity and positive predictive values were calculated. RESULTS: The number of subjects with coronary calcification(totalcalcium score>0) detected by spiral CT were 20(80%) of 25 with coronary artery disease and 2(33%) of 6 without coronary artery disease. The sensitivity, specificity, and positive predictive values were 80%, 67% and 91% respectively. Sensitivity was 64%, specificity was 80% in patients aged < or =60. Sensitivity was 76% and specificity was 83%(total calcium score 10). CONCLUSION: Quantification of coronary artery calcification using spiral CT haslow specificity in the older group and low sensitivity in the younger group ; the procedure is therefore may notbe useful as a non invase screening test to predict the prescence of coronary artery disease. In the younger group, however, a cardiac workup is strongly indicated if calcification is present.