CT Angiography of the Aorta: Contrast Timing by Using a Fixed versus a Patient-specific Trigger Delay

Area of Science:

• Radiology
• Medical Imaging
• Cardiovascular Imaging

Background:

• Optimal timing for contrast media bolus in CT angiography is challenging due to short scanner durations and patient variability.
• Accurate contrast timing is essential for effective CT angiography of the aorta.

Purpose of the Study:

• To compare contrast opacification in CT angiography of the aorta using fixed versus patient-specific individualized trigger delays for contrast media timing with bolus tracking.

Main Methods:

• Prospective study comparing two cohorts: fixed trigger delay (4 seconds) and individualized trigger delay (6.4-11.3 seconds) for CT angiography of the thoracoabdominal aorta.
• Objective and subjective image quality assessments were performed.
• Statistical analysis included Student t test and Wilcoxon-Mann-Whitney test.

Main Results:

• The individualized cohort showed significantly higher overall attenuation (486 HU vs 438 HU; P < .001) and uniform attenuation distribution.
• Contrast-to-noise ratio (P = .04) and subjective image quality (100% excellent/good vs 67%; P < .001) were superior in the individualized cohort.
• No significant difference in image noise was observed between the cohorts.

Conclusions:

• Patient-specific individualized trigger delay significantly enhances image quality in CT angiography of the aorta.
• Individualized trigger delay ensures uniform contrast attenuation, outperforming fixed delay protocols.
• This approach addresses challenges in contrast timing for modern CT scanners.