Reduction of radiation exposure and improvement of image quality with BMI-adapted prospective cardiac computed tomography and iterative reconstruction.

PURPOSE To assess the impact of body mass index (BMI)-adapted protocols and iterative reconstruction algorithms (iDose) on patient radiation exposure and image quality in patients undergoing prospective ECG-triggered 256-slice coronary computed tomography angiography (CCTA). METHODS Image quality and radiation exposure were systematically analyzed in 100 patients. 60 Patients underwent prospective ECG-triggered CCTA using a non-tailored protocol and served as a 'control' group (Group 1: 120 kV, 200 mAs). 40 Consecutive patients with suspected coronary artery disease (CAD) underwent prospective CCTA, using BMI-adapted tube voltage and standard (Group 2: 100/120 kV, 100-200 mAs) versus reduced tube current (Group 3: 100/120 kV, 75-150 mAs). Iterative reconstructions were provided with different iDose levels and were compared to filtered back projection (FBP) reconstructions. Image quality was assessed in consensus of 2 experienced observers and using a 5-grade scale (1=best to 5=worse), and signal- and contrast-to-noise ratios (SNR and CNR) were quantified. RESULTS CCTA was performed without adverse events in all patients (n=100, heart rate of 47-87 bpm and BMI of 19-38 kg/m2). Patients examined using the non-tailored protocol in Group 1 had the highest radiation exposure (3.2±0.4 mSv), followed by Group 2 (1.7±0.7 mSv) and Group 3 (1.2±0.6 mSv) (radiation savings of 47% and 63%, respectively, p<0.001). Iterative reconstructions provided increased SNR and CNR, particularly when higher iDose level 5 was applied with Multi-Frequency reconstruction (iDose5 MFR) (14.1±4.6 versus 21.2±7.3 for SNR and 12.0±4.2 versus 18.1±6.6 for CNR, for FBP versus iDose5 MFR, respectively, p<0.001). The combination of BMI adaptation with iterative reconstruction reduced radiation exposure and simultaneously improved image quality (subjective image quality of 1.4±0.4 versus 1.9±0.5 for Group 2 reconstructed using iDose5 MFR versus Group 1 reconstructed using FBP, p<0.05). CONCLUSIONS Prospective ECG-triggered 256-slice CCTA allows for visualization of the coronary artery tree with high image quality within a wide range of heart rates and BMIs. The combination of BMI-adapted protocols with iterative reconstruction algorithms can reduce radiation exposure for the patients and simultaneously improve image quality.

[1]  Udo Hoffmann,et al.  Characterization of non-calcified coronary atherosclerotic plaque by multi-detector row CT: comparison to IVUS. , 2007, Atherosclerosis.

[2]  Bernhard Bischoff,et al.  Impact of a reduced tube voltage on CT angiography and radiation dose: results of the PROTECTION I study. , 2009, JACC. Cardiovascular imaging.

[3]  H. Alkadhi,et al.  Radiation dose of cardiac dual-source CT: the effect of tailoring the protocol to patient-specific parameters. , 2008, European journal of radiology.

[4]  Marco Valgimigli,et al.  Diagnostic performance of multislice spiral computed tomography of coronary arteries as compared with conventional invasive coronary angiography: a meta-analysis. , 2006, Journal of the American College of Cardiology.

[5]  Effect of iterative reconstruction techniques on image texture , 2011 .

[6]  J. Leipsic,et al.  Adaptive statistical iterative reconstruction: assessment of image noise and image quality in coronary CT angiography. , 2010, AJR. American journal of roentgenology.

[7]  Philipp Bruners,et al.  Low Tube Voltage Improves Computed Tomography Imaging of Delayed Myocardial Contrast Enhancement in an Experimental Acute Myocardial Infarction Model , 2007, Investigative radiology.

[8]  K. Shyu,et al.  The diagnostic accuracy of 256-row computed tomographic angiography compared with invasive coronary angiography in patients with suspected coronary artery disease. , 2010, European heart journal.

[9]  H. Kauczor,et al.  Image quality and radiation dose in 256-slice cardiac computed tomography: comparison of prospective versus retrospective image acquisition protocols. , 2011, European journal of radiology.

[10]  Bernhard Bischoff,et al.  Image quality and radiation exposure with a low tube voltage protocol for coronary CT angiography results of the PROTECTION II Trial. , 2010, JACC. Cardiovascular imaging.

[11]  N. Bellenger,et al.  A comparison of radiation doses between state-of-the-art multislice CT coronary angiography with iterative reconstruction, multislice CT coronary angiography with standard filtered back-projection and invasive diagnostic coronary angiography , 2010, Heart.

[12]  S. Achenbach,et al.  Relationship between degree of remodeling and CT attenuation of plaque in coronary atherosclerotic lesions: an in-vivo analysis by multi-detector computed tomography. , 2008, Atherosclerosis.

[13]  Jörg Hausleiter,et al.  Estimated radiation dose associated with cardiac CT angiography. , 2009, JAMA.

[14]  Reduction of Radiation Dose Estimates in Cardiac 64-Slice CT Angiography in Patients After Coronary Artery Bypass Graft Surgery , 2008, Investigative radiology.

[15]  R. Morin,et al.  Ionizing Radiation in Cardiac Imaging: A Science Advisory From the American Heart Association Committee on Cardiac Imaging of the Council on Clinical Cardiology and Committee on Cardiovascular Imaging and Intervention of the Council on Cardiovascular Radiology and Intervention , 2009, Circulation.

[16]  Fuminari Tatsugami,et al.  Feasibility of low-dose coronary CT angiography: first experience with prospective ECG-gating. , 2007, European heart journal.

[17]  E. Samei,et al.  Low-tube-voltage, high-tube-current multidetector abdominal CT: improved image quality and decreased radiation dose with adaptive statistical iterative reconstruction algorithm--initial clinical experience. , 2010, Radiology.

[18]  Jiang Hsieh,et al.  Prospectively gated transverse coronary CT angiography versus retrospectively gated helical technique: improved image quality and reduced radiation dose. , 2008, Radiology.

[19]  J. Remy,et al.  Chest computed tomography using iterative reconstruction vs filtered back projection (Part 1): evaluation of image noise reduction in 32 patients , 2011, European Radiology.

[20]  M. Kalra,et al.  Radiation Dose Reduction With Chest Computed Tomography Using Adaptive Statistical Iterative Reconstruction Technique: Initial Experience , 2010, Journal of computer assisted tomography.

[21]  A. Einstein,et al.  Estimating risk of cancer associated with radiation exposure from 64-slice computed tomography coronary angiography. , 2007, JAMA.

[22]  Masanori Takada,et al.  Radiation dose reduction and coronary assessability of prospective electrocardiogram-gated computed tomography coronary angiography: comparison with retrospective electrocardiogram-gated helical scan. , 2008, Journal of the American College of Cardiology.

[23]  Ulrich Baum,et al.  Usefulness of multidetector row spiral computed tomography with 64- x 0.6-mm collimation and 330-ms rotation for the noninvasive detection of significant coronary artery stenoses. , 2006, The American journal of cardiology.

[24]  H. Kauczor,et al.  Quantitative assessment of stenosis severity and atherosclerotic plaque composition using 256-slice computed tomography , 2010, European Radiology.

[25]  Borut Marincek,et al.  Radiation dose estimates in dual-source computed tomography coronary angiography , 2008, European Radiology.