Contrast-dose relation in first-pass myocardial MR perfusion imaging.

Area of Science:

• Cardiovascular Magnetic Resonance (CMR) Imaging
• Medical Imaging Physics
• Myocardial Perfusion Assessment

Background:

• Accurate quantification of myocardial perfusion using cardiovascular magnetic resonance (CMR) is crucial for diagnosing and managing cardiac diseases.
• First-pass perfusion CMR relies on the signal intensity changes induced by gadolinium-based contrast agents (GBCAs).
• Understanding the relationship between GBCA dose and signal intensity is essential to avoid saturation artifacts and ensure quantitative accuracy.

Purpose of the Study:

• To determine the linear contrast enhancement regime in first-pass perfusion CMR.
• To establish optimal gadolinium-based contrast agent (GBCA) dosing for accurate myocardial perfusion quantification.
• To identify the dose thresholds beyond which signal intensity becomes non-linear.

Main Methods:

• Ten healthy subjects underwent perfusion CMR on a 1.5T scanner.
• Seven doses of Gd-DTPA (0.00125 to 0.1 mmol/kg b.w.) were administered via rapid bolus injection.
• Linear regression analysis was used to determine the linear contrast-dose relationship in the left ventricular (LV) blood pool and myocardium.

Main Results:

• MR signal intensity demonstrated a linear increase with GBCA dose up to 0.01 mmol/kg in the LV blood pool.
• Linear signal intensity response in the myocardium was observed up to 0.05 mmol/kg of Gd-DTPA.
• Signal intensity response became non-linear at higher GBCA concentrations, indicating saturation.

Conclusions:

• Quantitative myocardial perfusion assessment in CMR must account for signal saturation effects.
• The identified linear regimes provide critical parameters for optimizing GBCA administration in perfusion CMR.
• Accurate quantification necessitates staying within the determined linear contrast-dose relationships to avoid saturation in both blood pool and myocardium.