Optimization of Contrast and Radiation Dose via Task-Specific keV Selection in PCD-CT

Overview

This pilot animal study evaluated task-based automatic keV selection in photon-counting detector CT angiography (PCD-CTA) to optimize radiation and contrast media (CM) doses while maintaining consistent contrast-to-noise ratio (CNR). Four CTA protocols varying radiation and CM doses were tested in six minipigs, demonstrating that tailored dose adjustments can preserve image quality with potential for dose reduction.

Background

CT angiography image quality depends on the contrast-to-noise ratio between vasculature and surrounding tissues, influenced by radiation and CM doses. Low tube voltage scanning enhances iodine contrast, allowing radiation dose reduction, but may require CM dose adjustments to maintain CNR. Photon-counting detector CT (PCD-CT) offers inherent spectral information and task-based automatic keV selection, enabling optimized virtual monoenergetic image (VMI) reconstruction and radiation dose modulation to achieve desired image quality. Prior phantom studies showed dose reductions, but in vivo validation is needed due to dynamic CM kinetics.

Data Highlights

Key Findings

• Task-based automatic keV selection successfully optimized VMI energy levels to maintain consistent CNR across varying radiation and CM doses.
• Reducing radiation dose while keeping CM dose constant preserved image quality in PCD-CTA.
• Reducing CM dose at constant radiation dose also maintained adequate CNR, beneficial for patients sensitive to contrast media.
• Further radiation dose reduction compensated by increased CM dose was feasible without compromising CNR.
• Repeated protocols across separate scan sessions demonstrated reproducibility of the dose optimization approach.

Clinical Implications

Task-based automatic keV selection in PCD-CT allows personalized balancing of radiation and CM doses to maintain image quality, potentially reducing patient exposure to ionizing radiation or nephrotoxic contrast agents. This approach may be particularly advantageous for vulnerable populations such as elderly patients with nephropathy or younger patients sensitive to radiation. Implementing such protocols could enhance safety without sacrificing diagnostic confidence in CT angiography.

Conclusion

This pilot in vivo study demonstrates that task-specific automatic keV selection in PCD-CT enables effective optimization of radiation and contrast media doses while preserving image quality. These findings support further clinical evaluation of personalized dose management strategies in CT angiography.

References

1. Siemens Healthineers AG -- NAEOTOM Alpha PCD-CT System
2. Prior Studies -- Low Tube Voltage and VMI in CTA
3. Animal Welfare Committee Approval -- Göttingen Minipig Study