Personalization of injection protocols to the individual patient's blood volume and automated tube voltage selection (ATVS) in coronary CTA

Purpose The aim was to assess personalised contrast media (CM) protocols-based on patient's blood volume (BV) and automated tube voltage selection (ATVS)-in coronary computed tomography angiography (CCTA). Methods A total of 114 consecutive patients received an ECG-triggered or ECG-gated helical scan on a 3rd -generation dual-source CT with 70-120kV (ATVS) and 330mAs(qual.ref.) CM was adapted to BV, scan time (s) and kV. Image quality (IQ) was assessed in a 17-segment coronary model using attenuation values (HU), contrast-to-noise (CNR), signal-to-noise ratio (SNR) (objective IQ) and a Likert scale (subjective IQ: 1 = poor/2 = sufficient/3 = good/4 = excellent). ig Results Patient distribution was: n = 60 for 70kV, n = 37 80kV and n = 17 90kV. Mean BV was 5.4 +/- 0.6L for men and 4.1 +/- 0.6L for women. Mean CM volume (300 mg l/mL) and flow rate were: 30.9 +/- 6.4mL and 3.3 +/- 0.5mL/s (70kV); 40.8 +/- 7.1mL and 4.5 +/- 0.6mL/s (80kV); 53.6 +/- 8.6mL and 5.7 +/- 0.6mL/s (90kV). Overall mean HU was >300HU in 98.2% (112/114) of patients. Overall mean attenuation was below 300HU in two scans (70kV) due to late scan timing. Of 1.661 segments, 95.4% was assessable. Mean CNR was 14 +/- 4(70kV), 13 +/- 3(80kV) and 14 +/- 4(90kV); mean SNR was 10 +/- 2(both 70kV+80kV) and 9 +/- 2(90kV). Objective IQ was comparable between kV settings, protocols and sex. Subjective IQ was diagnostic in all scans and excellent-sufficient in 95.4% of segments. Conclusions Personalisation of CCTA CM injection protocols to BV and ATVS is a promising technique to tailor CM administration to the individual patient, while maintaining diagnostic IQ.