contrast timing bolus
Small test injection of contrast material used to determine optimal timing for main contrast bolus in vascular imaging studies.
Full Definition
A contrast timing bolus, also called a test bolus, is a preliminary injection of a small amount (typically 10-20 mL) of contrast material used to determine the optimal delay time for the main contrast injection in CT angiography or venography. This technique ensures peak arterial or venous enhancement during image acquisition, critical for diagnostic quality in vascular imaging. The timing bolus helps account for individual patient variations in circulation time, cardiac output, and vascular pathology. Editors must distinguish this from bolus tracking (automated detection) and understand that timing bolus protocols vary between arterial and venous phase imaging. The term appears frequently in imaging protocols and technical parameter descriptions.
Usage
Usage note: Hyphenate when used as a compound modifier; distinguish from 'bolus timing' (the process).
In Context
- "A 15 mL contrast timing bolus was administered to determine peak enhancement." — CT angiography protocol
- "The timing bolus showed delayed circulation, requiring adjustment of the main injection delay." — Vascular imaging report