Whole-Body High-Pitch CT Angiography: Strategies to Reduce Radiation Dose and Contrast Volume

Area of Science:

• Radiology and Imaging
• Medical Physics
• Cardiovascular Imaging

Background:

• Dual-source high-pitch CT angiography (CTA) is a crucial diagnostic tool.
• Optimizing contrast material concentration, volume, and voltage is essential for reducing radiation dose and contrast load.
• Evaluating novel protocols for enhanced patient safety and imaging efficiency is ongoing.

Purpose of the Study:

• To assess the noninferiority of a novel dual-source high-pitch CTA protocol.
• The protocol utilizes high-concentration (iopamidol 370), low-volume (60 mL) iodinated contrast material at low voltage (100 kVp).
• To compare this method against standard-of-care CTA using low-concentration (iopamidol 300), standard-volume (75 mL) contrast at high voltage (120 kVp), focusing on radiation dose and contrast volume reduction without compromising vascular opacification.

Main Methods:

• A phantom study evaluated contrast enhancement across various dilutions and acquisition parameters.
• Organ-based radiation profiles were assessed using metal-oxide-semiconductor field-effect transistors in an anthropomorphic phantom.
• A prospective study enrolled 150 patients randomized into three groups receiving different contrast volumes/concentrations and kVp/mAs settings; vascular signal-to-noise ratio and homogeneity were analyzed.

Main Results:

• In vitro analysis confirmed noninferiority of the high-concentration, low-voltage protocol compared to the standard protocol.
• Significant reductions in radiation dose were observed with the 100 kVp, 240 mAs protocol (p < 0.0001).
• Noninferior vascular contrast and luminal homogeneity were achieved across all high-pitch protocols, with significantly decreased radiation dose noted for protocols using 60 mL and 75 mL of iopamidol 370 at 100 kVp and 240 mAs.

Conclusions:

• Dual-source high-pitch CTA with high-concentration, low-volume contrast at low voltage is noninferior to standard high-voltage CTA.
• This optimized protocol enables a simultaneous reduction in radiation dose and contrast volume.
• The findings support the adoption of this advanced CTA technique for improved patient safety and resource utilization without compromising diagnostic image quality.