Optimizing coronary CT angiography in patients with delayed contrast arrival using a free-breathing, high-threshold...

Area of Science:

• Cardiovascular Imaging
• Radiology
• Medical Technology

Background:

• Coronary computed tomography angiography (CCTA) is crucial for diagnosing coronary artery disease.
• Conventional CCTA protocols can be limited by breath-hold requirements and suboptimal contrast enhancement, particularly in patients with delayed contrast arrival.
• Improving image quality and consistency in CCTA is essential for accurate diagnosis.

Purpose of the Study:

• To evaluate the effectiveness of a free-breathing, high-threshold bolus-tracking CCTA protocol.
• To assess its impact on coronary enhancement and diagnostic visualization in patients with delayed contrast arrival.
• To compare its performance against conventional breath-hold CCTA protocols.

Main Methods:

• A prospective study randomized 159 patients to either a conventional (breath-hold, 100 HU threshold) or modified (free-breathing, 300 HU threshold) bolus-tracking protocol.
• Patients were stratified into normal and delayed contrast arrival groups based on contrast arrival time (Tarr).
• Coronary attenuation, enhancement uniformity (COV), phase distribution, and image quality were analyzed.

Main Results:

• The modified protocol significantly improved coronary attenuation and enhancement uniformity (COV: 11.28% vs 16.73%, p < 0.001) in patients with delayed contrast arrival.
• Excellent image quality was achieved in a higher proportion of segments (94.2% vs 86.8%, p = 0.004) with the modified protocol.
• The modified protocol resulted in more optimal-phase scans (19.4% vs 9.4%) and fewer late-phase acquisitions (32.3% vs 65.6%) in this subgroup.

Conclusions:

• The free-breathing, high-threshold bolus-tracking CCTA protocol enhances diagnostic visualization and acquisition consistency.
• It offers a more reliable and patient-tolerant alternative for CCTA, especially for individuals with delayed contrast transit.
• This strategy may broaden CCTA's clinical utility in patients with impaired breath-hold capacity or circulatory dynamics.