Revisiting test bolus: a plug-and-play solution for cardiac CTA timing

Area of Science:

• Radiology
• Cardiovascular Imaging
• Pediatric Cardiology

Background:

• Cardiac computed tomography angiography (CTA) for congenital heart disease (CHD) presents technical challenges, especially in low-volume centers.
• Real-time radiologist supervision for cardiac CTA can strain resources and reduce productivity.

Purpose of the Study:

• To evaluate a standardized, delay-corrected test-bolus timing method for cardiac CTA specifically for CHD.
• Assess the efficacy of this novel timing method in achieving diagnostic-quality imaging.

Main Methods:

• Retrospective review of 318 cardiac CTA examinations (November 2020 to August 2022).
• Comparison between a delay-corrected test-bolus timing cohort and a manually triggered control cohort.
• Quantitative enhancement (HU) and aorto-pulmonary differentiation were measured; non-inferiority was assessed using one-sided 95% confidence intervals.

Main Results:

• The test-bolus method met non-inferiority for absolute aortic enhancement (difference +24.1 HU).
• Left-sided examinations at 80 kVp showed significantly greater aorto-pulmonary separation with test-bolus timing (P<0.001).
• Balanced enhancement was observed for both-sided goals at 80 kVp (P=0.082).

Conclusions:

• A patient-specific, physiology-based test-bolus framework enables reliable congenital cardiac CTA.
• This method utilizes measured contrast dynamics to optimize scan timing.
• Diagnostic-quality target-vessel enhancement is achievable across various clinical goals.