Optimal timing for first-pass stress CT myocardial perfusion imaging

Area of Science:

• Cardiovascular Imaging
• Radiology
• Diagnostic Medicine

Background:

• CT-based myocardial perfusion imaging (CTP) offers accurate detection of myocardial perfusion defects, comparable to SPECT.
• Optimal timing is critical for single-phase first-pass stress CTP to maximize diagnostic accuracy.

Purpose of the Study:

• To establish precise timing guidelines for optimal single-phase first-pass stress CTP acquisitions.
• To determine the ideal time window for differentiating ischemic from non-ischemic myocardium.

Main Methods:

• 16 patients with suspected coronary artery disease underwent adenosine stress CTP and invasive coronary angiography with FFR measurements.
• Time-attenuation curves were analyzed in ischemic and non-ischemic myocardium, alongside aortic contrast enhancement.
• Optimal contrast difference (HU) between myocardial tissues was identified.

Main Results:

• Maximum contrast difference between ischemic and non-ischemic myocardium occurred 24-32 seconds post-contrast injection under adenosine stress.
• Optimal stress CTP imaging window identified as 8-16 seconds after aortic contrast exceeded 100 HU (or 7-15s after 150 HU).
• An approximately 8-second optimal time frame exists for differentiating ischemic from non-ischemic myocardium.

Conclusions:

• A specific time window exists for optimal contrast enhancement in stress CTP, crucial for accurate diagnosis.
• These findings provide practical guidance for optimizing single-phase first-pass stress CTP protocols.
• Precise timing enhances the differentiation of myocardial perfusion defects in patients with coronary artery disease.