Jian Cao MD, Abstract Co-Author: Nothing to Disclose

Yining Wang MD, Presenter: Nothing to Disclose

Lu Lin MD, Abstract Co-Author: Nothing to Disclose

Lingyan Kong MD, Abstract Co-Author: Nothing to Disclose

Yan Yi, Abstract Co-Author: Nothing to Disclose

Jiuhong Chen MD, PhD, Abstract Co-Author: Employee, Siemens AG

Zheng Yu Jin MD, Abstract Co-Author: Nothing to Disclose

To investigate the application of ultra low tube voltage (70kV) for coronary artery CT angiography (CCTA) with low contrast volume and injection flow rate on dual-source CT (DSCT) equipment with integrated circuit (IC) detector.

Thirty patients with body mass index (BMI) no more than 25 kg/m2 were scanned using high pitch (3.4) and prospectively ECG-triggering CCTA protocol on DSCT. All patients were givenβ-blocker before examination in order to make the mean heart rate lower than 70 bpm. All patients were randomly divided into two groups：the injection flow rate and volume of contrast for Group A was 4.0 mL/s and 32 mL(350 mgI/mL); those for Group B were 4.0 mL/s and 50 mL (350 mgI/mL), respectively. Tube voltage of both groups was 70 kV. The raw data were reconstructed with both FBP and sinogram affirmed iterative reconstruction (SAFIRE). The differences of SNR, CNR, noise, CTDIvol, effective dose (ED) and segment-based image quality (1-4, excellent to non-assessable) between the two groups were compared.

There were no significant differences in age, BMI or heart rate between the two groups (all P＞0.05). Radiation exposure (CTDIvol and ED) between the two groups showed no significant difference (all P＞0.05), and the mean ED was about 0.90 mSv. Besides, there were no significant differences between the two groups in SNR and CNR. By means of SAFIRE, the image noise decreased and CNR and SNR increased significantly (all P < 0.001). And the contrast CT value, SNR and CNR of each coronary artery segment reconstructed with SAFIRE were significantly higher than FBP in both groups (all P < 0.01), except in the distal segment of LAD, where there were no significant difference. Mean segment-based image quality scores showed no significant difference between the two groups reconstructed with SAFIRE (Group A, 1.16 ± 0.18, Group B, 1.18 ± 0.18; p = 0.75). The percentage of assessable segments in each group was more than 98%.

For patients with normal BMI, the use of tube voltage as 70kV with SAFIRE technique in DSCT equipped IC detector is feasible. And both the contrast injection flow rate and volume can be much lower.

For patients with BMI no more than 25 kg/m2 and mean heart rate of less than 70 bpm, the CCTA of ultra low tube voltage (70kV) and low contrast volume (4.0 mL/s, 32 mL) with high pitch scanning protocol is feasible.

Cao, J, Wang, Y, Lin, L, Kong, L, Yi, Y, Chen, J, Jin, Z, Ultra Low Tube Voltage (70kV) FLASH Scan with Low Contrast Volume Injection Protocol for Dual-source CT Coronary Angiography: Image Quality and Radiation Exposure.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14010212.html