Quantification of regional pulmonary blood flow using ASL-FAIRER

Area of Science:

• Cardiovascular System
• Medical Imaging
• Physiology

Background:

• Pulsed arterial spin labeling (ASL) is validated for cerebral blood flow (CBF) quantification.
• Pulmonary blood flow (PBF) measurement presents unique challenges due to high pulsatility and the physical gap between tagging and imaging regions.
• ASL techniques require adaptation for accurate PBF assessment.

Purpose of the Study:

• To measure regional pulmonary blood flow (rPBF) in healthy subjects using ASL-FAIRER.
• To compare the performance of single-subtraction and multiple-subtraction ASL strategies for rPBF quantification.
• To evaluate the theoretical framework for ASL in pulmonary perfusion imaging.

Main Methods:

• ASL-FAIRER technique applied to seven healthy subjects.
• Two ASL strategies investigated: single-subtraction (one tag-control pair at RR-interval) and multiple-subtraction (various inversion times).
• rPBF quantified and compared between the two ASL approaches.

Main Results:

• Mean rPBF measured by multiple-subtraction: 1.70 ± 0.38 ml/min/ml.
• Mean rPBF measured by single-subtraction: 1.66 ± 0.24 ml/min/ml (approximately 2% lower).
• Calculated regional perfusion: ~5.5 ml/g/min, comparable to other methods.

Conclusions:

• Both single- and multiple-subtraction ASL methods provide comparable rPBF measurements.
• The multiple-subtraction approach may offer slightly higher accuracy for rPBF.
• ASL acquisition and analysis for PBF require specific adaptations compared to CBF due to lung physiology.