Bo Ram Jun MD, Presenter: Nothing to Disclose

Hwan Seok Yong MD, Abstract Co-Author: Nothing to Disclose

Eun-Young Kang MD, Abstract Co-Author: Nothing to Disclose

Ok Hee Woo MD, Abstract Co-Author: Nothing to Disclose

Eun Jung Choi MD, PhD, Abstract Co-Author: Nothing to Disclose

The purpose of this study is to assess the feasibility of 80kV electrocardiogram (ECG)-gated coronary CT angiography (CCTA) in patients with a normal body mass index (BMI), compared to 120kV ECG-gated CCTA.

This retrospective study was approved by local ethics board; written informed consent was waived. The CCTA images of 100 subjects whose BMI was less than 25 kg/m2 were analyzed. Fifty subjects underwent standard CCTA using 120 kV and the other 50 subjects underwent low tube voltage CCTA using 80 kV. Two blinded observers independently evaluated subjective image quality of each coronary artery. Objective image quality {signal -to- noise ratio (SNR) and contrast -to- noise ratio (CNR)} and radiation dose were also measured in each group.

Though objective image quality of 80-kV images were significantly poorer than those of standard 120-kV images (mean SNR: 14.91 ± 4.71 vs 19.80 ± 4.41; mean CNR: 15.21 ± 4.78 vs 21.56 ± 4.66, P<0.0001), there was no significant difference in the subjective image quality between the two groups. Radiation dose exposure of the 80 kV protocol compared to the 120 kV was reduced by 70%. (3.42 ± 1.16 mSv vs 11.49 ± 3.62 mSv, P < 0.0001).

The low tube voltage CCTA protocol using 80 kV allows significant reduction of radiation dose without impairment of subjective image quality despite of the decrease in SNR and CNR even in patients with a normal BMI.

Our study could help to reduce the radiation dose without impairment of subjective image quality despite of the decrease in SNR and CNR even in patients with a normal BMI.

Jun, B, Yong, H, Kang, E, Woo, O, Choi, E, Low Tube Voltage 64-Slice Coronary CT Angiography Using 80 kV in Patients with a Normal Body Mass Index: Comparison with a Standard 120 kV Protocol.  Radiological Society of North America 2011 Scientific Assembly and Annual Meeting, November 26 - December 2, 2011 ,Chicago IL. http://archive.rsna.org/2011/11011585.html