JCMR 2021; 23.123. Pulmonary blood volume measured by cardiovascular magnetic resonance: influence of pulmonary transit time methods and left atrial volume-Pulmonary blood volume article

Pulmonary blood volume article

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This study compared different cardiovascular magnetic resonance (CMR) methods for measuring pulmonary blood volume (PBV), an indicator of pulmonary congestion relevant to heart failure.<br /><br />Fifty-eight participants (21 healthy controls, 37 patients) underwent CMR. The reference method, CoG(PA-LA), measured pulmonary transit time between the pulmonary artery and left atrium using a separate contrast injection. Three first-pass perfusion (FPP) methods were tested: pulmonary transit beats (PTB), peak-to-peak, and center of gravity (CoG). Because FPP images are acquired in the left ventricle rather than the left atrium, they inherently include left atrial volume (LAV), which can make PBV appear higher.<br /><br />Compared with the reference method, FPP-based PBV was consistently overestimated by about 14–18%. When mean LAV was subtracted, the differences became small: about 1–3% overall. Among the FPP methods, CoG(FPP) showed the best precision and lowest interobserver variability, while PTB and peak-to-peak were less robust.<br /><br />The main conclusion is that FPP methods do not measure exactly the same volume as CoG(PA-LA); instead, they measure PBV plus LAV. Therefore, FPP-derived values should be interpreted as PBV + LAV unless corrected for atrial volume. The study suggests that CoG(FPP) is the best practical method for clinical use because it is precise, reproducible, and available “for free” during routine myocardial perfusion imaging.

Keywords

cardiovascular magnetic resonance

pulmonary blood volume

pulmonary congestion

heart failure

first-pass perfusion

left atrial volume

pulmonary transit time

center of gravity

interobserver variability

myocardial perfusion imaging