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PURPOSE: To assess the image quality of 256-slice computed tomographic angiography (CTA) and to identify possible impact factors associated with image quality. METHODS: From November 2009 to January 2010, 506 patients underwent 256-slice CTA at our institute. A total of 451 patients were enrolled in our study, after 55 patients were excluded because of prior bypass surgery and stenting. CTA image quality was graded by two observers using a 4-point scale: excellent (score 1), good (score 2), moderate (score 3), poor and non-diagnostic (score 4). The coronary arteries were divided into 15 segments. Image quality was correlated to the subjects' age, gender, body mass index, heart rate, and calcium scores. RESULTS: We evaluated 6650 coronary segments from CTA images of our enrolled 451 patients. The mean image quality score of all coronary segments was 1.14. Most coronary segments (99.7%) were assessable, and only 21 segments (0.3%) were non-diagnostic. A total of 5824 coronary segments were classified as having excellent image quality. Forty-two patients (9.3%) required control of heart rate with beta-blockers before CTA could be performed. Male patients had better image quality than female patients. Heart rate and severity of calcification were impact factors associated with image quality. CONCLUSIONS: Examination with 256-slice CTA provides good image quality and can effectively evaluate most coronary segments. KEY WORDS: Coronary angiography; Heart rate; Image quality; Multi-slice computed tomography.
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PUPOSE: The newer 256-slice computed tomography coronary angiography (CTCA) has the capability of improving diagnostic performance in the detection of obstructive coronary artery disease (CAD) compared to 64-slice CTCA. The aim of this study was to compare the diagnostic performance of 64- versus 256-slice CTCA in two similar populations. METHODS: Our study included 120 consecutive patients who were referred for CTCA and subsequently underwent conventional coronary angiography (CCA). Sixty patients were studied by 64-slice CTCA, with the other 60 by 256-slice CTCA. We compared the technical characteristics and diagnostic performance of 64- and 256-slice CTCA for the detection of ≥ 50% stenosis of the coronary arteries on CCA. RESULTS: The 256-slice CTCA had a shorter scanning time (4.4 ± 0.6 sec vs. 5.0 ± 0.7 sec, p < 0.001) compared to 64-slice CTCA. The diagnostic accuracy rates of 256-slice CTCA based on patient analysis (97% vs. 83%, p < 0.05), vessel analysis (95% vs. 85%, p < 0.05), and segment analysis (94% vs. 88%, p < 0.05) were significantly superior to those of 64-slice CTCA. The diagnostic accuracy rates of 64- and 256-slice CTCA were affected by the presence of stent (65% vs. 75%, respectively, p > 0.05) and severe calcifications (75% vs. 82%, respectively, p > 0.05). CONCLUSIONS: In two similar populations, 256-slice CTCA displayed superior diagnostic performance than 64-slice CTCA. However, the performance of 256-slide CTCA is affected in those segments that are severely calcified and/or stented. KEY WORDS: Computed tomography coronary angiography (CTCA); Conventional coronary angiography; Diagnostic performance; 64-slice helical CTCA; 256-slice helical CTCA.
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AIMS: To assess the diagnostic accuracy of 256-row computed tomographic angiography (CTA) in patients with suspected coronary artery disease (CAD). Non-invasive imaging of the coronary artery by CTA has increasingly been used in recent years. The accuracy of 256-row CTA has not yet been studied. We sought to assess the accuracy of 256-row CTA compared with invasive coronary angiography (ICA) in the diagnosis and assessment of CAD. METHODS AND RESULTS: We prospectively evaluated 104 consecutive individuals who accepted CTA and then underwent ICA. The presence of stenosis > or =50% was considered obstructive. The diagnostic accuracy of CTA for detecting obstructive stenosis was compared with that of ICA. The area under the receiver-operating-characteristic curve (AUC) was used to evaluate the diagnostic accuracy of CTA relative to ICA. A total of 86 patients had obstructive CAD. The patient-based analysis of CTA for detecting stenosis > or =50% according to ICA revealed an AUC of 0.744 [95% confidence interval (CI), 0.572-0.916], with a sensitivity of 98.8%, a specificity of 50%, a positive predictive value (PPV) of 92.4%, and a negative predictive value (NPV) of 87.5%. The segment-based analysis revealed an AUC of 0.915 (95% CI, 0.847-0.982), with a sensitivity of 93.5%, a specificity of 95%, a PPV of 77.6%, and an NPV of 98.7%. The vessel-based analysis revealed an AUC of 0.887 (95% CI, 0.808-0.966), with a sensitivity of 94.3%, a specificity of 87.3%, a PPV of 82.7%, and an NPV of 95.9%. CONCLUSION: 256-Row CTA is a highly sensitive test of CAD and has a high predictive value. 256-Row CTA may be a potential alternative to detect coronary artery stenosis and rule out CAD in suspected patients.