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1870. Evaluation of a Tube-Voltage Tailored Contrast Media Injection Protocol for Coronary CT Angiography
Authors * Denotes Presenting Author
  1. Basel Yacoub *; Medical University of South Carolina
  2. Domenico De Santis; Medical University of South Carolina; Sapienza University of Rome
  3. Akos Varga-Szemes; Medical University of South Carolina
  4. Joseph Schoepf; Medical University of South Carolina
  5. Richard Bayer; Medical University of South Carolina
  6. Tilman Emrich; Medical University of South Carolina; University Medical Center Mainz
  7. Simon Martin; Medical University of South Carolina; University Hospital Frankfurt
Objective:
To evaluate a tube voltage-tailored contrast media (CM) application protocol utilizing software support for patient-specific injection during coronary CT angiography (CCTA).

Materials and Methods:
In this IRB-approved, HIPAA-compliant single-center study, 120 patients referred to CCTA were prospectively assigned to a tube voltage-tailored CM injection protocol. Automated tube voltage selection (ATVS), which automatically adjusts kV to the patient's body habitus, ranged from 70 to 130 kV by applying 10 kV intervals. The iodine delivery rate (IDR) was adapted to the tube voltage level using a dedicated software (Bayer / Medrad, Indianola, PA). The administrated CM volume ranged from 33 mL at 70 kV (IDR, 0.8 gI/s) to 65 mL at 130 kV (IDR, 1.9 gI/s). Attenuation measurements were performed in the aorta and coronary arteries to calculate quantitative signal-to-noise (SNR) and contrast-to-noise (CNR) ratios. Five-point scales were used to evaluate overall image quality. Radiation metrics were assessed (Radimetrics™, Bayer) and compared between the protocols.

Results:
The mean age of the study patients was 62.5 ± 11.9 years. Image quality was rated as diagnostic in all patients. Contrast enhancement peaked at 70 kV (P<0.001), while SNR and CNR parameters showed no significant differences between the tube voltages (P>=0.085). Additionally, no significant differences were found for subjective image quality parameters between the different protocols (P>=0.139). The lowest radiation dose values were observed in the group of patients assigned to the 70-kV protocol with a median effective radiation dose of 1.1 mSv (P<0.001).

Conclusion:
The proposed tube voltage-tailored injection protocol allows for an individualized scanning of patients undergoing CCTA with significant reductions radiation dose and contrast media administered while simultaneously maintaining a high diagnostic image quality.