320-row CT coronary angiography: effect of 100-kV tube voltages on image quality, contrast volume, and radiation dose.
To prospectively evaluate image quality parameters, contrast volume and radiation dose at the 100-kilovolt (kV) setting during coronary computed tomographic angiography (CCTA) on a 320-row computed tomography scanner. We enrolled 107 consecutive patients with a heart rate <65 beats per minute (bpm) undergoing prospective electrocardiogram (ECG)-triggered CCTA. Forty patients with a body mass index (BMI) <25 kg/m(2) were scanned using 100-kV tube voltage settings, while 67 patients were scanned using 120-kV protocols. Image quality was assessed by two readers unaware of patient information and scan parameters. Attenuation in the aorta and perivascular fat tissue and image noise were measured. Contrast-to-noise ratios (CNRs) and contrast material volumes were calculated. The effective radiation doses were estimated using a chest conversion coefficient (0.017). Diagnostic image quality was achieved in 98.2% of coronary segments with 100-kV CCTA and 98.6% of coronary segments with 120-kV CCTA, with no significant differences in image quality scores for each coronary segment. Vessel attenuation, image noise, and CNR were not significantly different between the 100- and 120-kV protocols. Mean contrast injection rate and mean material volume were significantly lower for the 100-kV CCTA (4.35 ± 0.28 ml/s and 53.13 ± 3.77 ml, respectively) than for the 120-kV CCTA (5.16 ± 0.21 ml/s and 62.40 ± 3.66 ml respectively; P < 0.001). The effective radiation dose was 2.12 ± 0.19 mSv for 100-kV CCTA, a reduction of 54% compared to 4.61 ± 0.82 mSv for 120-kV CCTA. A 100-kV CCTA can be implemented in patients with a BMI < 25 kg/m(2). The 100-kV setting allows significant reductions in contrast material volume and effective radiation dose while maintaining adequate diagnostic image quality.
Department of Radiology, Beijing Anzhen Hospital, Capital Medical University, 2 Anzhen Road, 100029, Chaoyang District, Beijing, People's Republic of China.
Chuanchen
C
Zhang
Zhaoqi
Z
Zhang
Zixu
Z
Yan
Lei
L
Xu
Wei
W
Yu
Rui
R
Wang
D000368:Aged; D015992:Body Mass Index; D055424:Cardiac-Gated Imaging Techniques; D016009:Chi-Square Distribution; D002681:China; D003287:Contrast Media; D017023:Coronary Angiography / Q000379:methods*; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging*; D004562:Electrocardiography; D005240:Feasibility Studies; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011829:Radiation Dosage; D011857:Radiographic Image Interpretation, Computer-Assisted; D014057:Tomography, X-Ray Computed
D003287:Contrast Media