128-slice dual-source CT coronary angiography using highpitch scan protocols in 102 patients

Transcription

1 128-slice dual-source CT coronary angiography using highpitch scan protocols in 102 patients Poster No.: C-0634 Congress: ECR 2010 Type: Scientific Exhibit Topic: Cardiac Authors: Y. H. Choe, J. W. Lee, E. Y. Kim; Seoul/KR Keywords: Dual-source CT coronary angiography, high pitch, image quality, radiation dose DOI: /ecr2010/C-0634 Any information contained in this pdf file is automatically generated from digital material submitted to EPOS by third parties in the form of scientific presentations. References to any names, marks, products, or services of third parties or hypertext links to thirdparty sites or information are provided solely as a convenience to you and do not in any way constitute or imply ECR's endorsement, sponsorship or recommendation of the third party, information, product or service. ECR is not responsible for the content of these pages and does not make any representations regarding the content or accuracy of material in this file. As per copyright regulations, any unauthorised use of the material or parts thereof as well as commercial reproduction or multiple distribution by any traditional or electronically based reproduction/publication method ist strictly prohibited. You agree to defend, indemnify, and hold ECR harmless from and against any and all claims, damages, costs, and expenses, including attorneys' fees, arising from or related to your use of these pages. Please note: Links to movies, ppt slideshows and any other multimedia files are not available in the pdf version of presentations. Page 1 of 15

2 Purpose Multi-detector computed tomography (CT) is an established noninvasive modality to assess coronary arteries with good diagnostic accuracy and improved image quality, especially using the dual-source CT (DSCT). With recent advance of CT images, 128-slice DSCT using high-pitch has been introduced for CT coronary angiography. The purpose of this study is to evaluate image quality and radiation dose on dual-source CT coronary angiography (DSCTCA) using high-pitch scan protocols. Methods and Materials Patients Total 102 consecutive patients Most of the patients had no history of coronary artery disease, and were presumed on low probability of coronary artery disease. Premedication mg of #-blocker (metoprolol), if HR > 75 bpm mg of nitroglycerin, sublingually CT protocols 1. Dual-source CT system Scan mode : Flash spiral (prospectively triggered) Collimation : 2 x 128 x 0.6 mm Tube potential : 100 kv or 120 kv Tube current : 320 mas/rotation Temporal resolution : 75 msec Pitch : 3.4 (coronary only, [C] protocol), or 3.2 (chest pain, [P] protocol) Spatial resolution : 0.33 mm Reconstruction kernel : medium-soft convolution kernel (B26f) Page 2 of 15

3 2. Nonionic contrast material, intravenously Total 70 ml (range, ml), at 4 ml/s Followed by a 40 ml of saline, at 4 ml/s 3. Bolus tracking In the ascending aorta, trigger level 100HU Additional delay : 5 sec 4. Scan area [C] protocol : From the level of 1 cm below the carina to the diaphragm [P] protocol : Whole thorax Assessment of CT images Two radiologists, in a consensus 16-segment classification model of the American Heart Association Image quality ; 4-point scales (figure 1) Excellent with no artifacts Good with minor artifacts or mild blurring Adequate with moderate artifacts of moderate blurring without luminal discontinuity Inadequate with severe artifact or luminal discontinuity Objective data 1)Image noise Standard deviation of HU ROI in the left atrium (figure 2) 2)Signal-to-noise ratio (SNR) Mean values / standard deviation ROI in the proximal lumen of each coronary artery (figure 3) Page 3 of 15

4 3)Attenuation difference between ascending and descending aorta(ada-d) Difference of mean values ROI in the ascending and descending aorta (figure 4) Radiation dose Effective radiation dose (msv) = Individual dose-length product (DLP) x (organ weighted factor) Images for this section: Page 4 of 15

5 Fig. 1: image quality : 4-point scale Fig. 2: Image noise : ROI in the left atrium Page 5 of 15

6 Fig. 3: Signal-to-noise ratio : ROI in the proximal segment of each coronary artery Page 6 of 15

7 Page 7 of 15

8 Fig. 4: Attenuation difference between the ascending and the descending aorta : ROI in the aorta Page 8 of 15

9 Results Patients and CT protocols (figure 1) Image quality overall results (figure 2) per-artery analysis (figure 3) per-segment analysis (figure 4) representative case (figure 5) Objective data of CT images overall results (figure 6) per-protocol analysis (figure 7) Effective radiation dose overall results (figure 8) per-protocol analysis (figure 9) LIMITATIONS The image quality score may be affected by relatively subjective 4-point scales. The number of patients using [P] protocol with pitch of 3.2 was relatively small. We had not assess in cases with high heart rate of high probability of coronary artery diseases. Images for this section: Page 9 of 15

10 Fig. 1: Patients and CT protocol Fig. 2: Image quality: overall results Page 10 of 15

11 Fig. 3: Image quality : per-artery analysis Fig. 4: Image quality : per-segment analysis Page 11 of 15

12 Fig. 5: Representative case Fig. 6: Objective data : overall results Page 12 of 15

13 Fig. 7: Objective data : per-protocol analysis Fig. 8: Radiation dose : overall results Fig. 9: Radiation dose : per-protocol analysis Page 13 of 15

14 Conclusion DSCTCTA using high-pitch protocols enables coronary artery imaging with sufficient image quality and remarkably low radiation dose. Fig.: DSCTCTA : curved-planar image, volume-rendered image, tree-view image References: Y. H. Choe; Radiology, Samsung Medical Center, Seoul, KOREA, Republic of References Halliburton SS, Sola S, Kuzmiak SA, et al. Effect of dual-source cardiac computed tomography on patient radiation dose in a clinical setting: comparison to single-source imaging. J Cardiovasc Comput Tomogr 2008;2: Hausleiter J, Meyer T, Hermann F, et al. Estimated radiation dose associated with cardiac CT angiography. JAMA 2009;301: Austen WG, Edwards JE, Frye RL, et al. A reporting system on patients evaluated for coronary artery disease. Report of the Ad Hoc Committee for Grading of Coronary Artery Disease, Council on Cardiovascular Surgery, American Heart Association. Circulation 1975;51:5-40 Matt D, Scheffel H, Leschka S, et al. Dual-source CT coronary angiography: image quality, mean heart rate, and heart rate variability. AJR Am J Roentgenol 2007;189: Wang M, Qi HT, Wang XM, Wang T, Chen JH, Liu C. Dose performance and image quality: Dual source CT versus single source CT in cardiac CT angiography. Eur J Radiol 2009;72: Page 14 of 15

15 6. 7. Scheffel H, Alkadhi H, Plass A, et al. Accuracy of dual-source CT coronary angiography: First experience in a high pre-test probability population without heart rate control. Eur Radiol 2006;16: Menzel HG, Schibilla H, Teumen D. European Guidelines on Quality Criteria for Computed Tomography. Luxembourg: European Commission, 2000:Publication No. EUR EN Personal Information Yeon Hyeon, Choe, MD., Ju Won, Lee, MD., Eun Young, Kim, MD. Department of Radiology, Samsung Medical Center, Sungkyunkwan University, Seoul, Korea Fig.: Samsung Medical Center References: Y. H. Choe; Radiology, Samsung Medical Center, Seoul, KOREA, Republic of Page 15 of 15