2021/10 - Pulmonary blood volume measured by cardiovascular magnetic resonance — influence of pulmonary transit time methods and left atrial volume [Journal Club]-Webinar

Video Transcription

Video Summary

This journal club session focused on a study by Håkon Heitun and colleagues about measuring pulmonary blood volume (PBV) with cardiac MRI. The key idea is that pulmonary transit time (PTT), especially when combined with cardiac output, can estimate how much blood is in the pulmonary circulation, offering a noninvasive marker of pulmonary congestion in heart failure.<br /><br />The study compared two approaches: a routine myocardial first-pass perfusion method and a dedicated pulmonary first-pass perfusion reference method. The main finding was that the routine clinical method is feasible “for free,” but it includes left atrial volume, which overestimates PBV. The dedicated pulmonary method excludes the left atrium and is more accurate, though it requires extra imaging and contrast.<br /><br />The center-of-gravity method for measuring transit time performed best, showing the highest accuracy and reproducibility. The speakers emphasized that PBV may be more clinically useful than PTT alone because it better reflects congestion rather than just flow speed. They also discussed indexing PBV, noting that body surface area is practical, but lung-related indexing may be more physiologic.<br /><br />Overall, the session highlighted PBV as a promising, potentially clinically implementable, noninvasive marker for assessing and tracking heart failure congestion.

Keywords

pulmonary blood volume

cardiac MRI

pulmonary transit time

heart failure congestion

myocardial first-pass perfusion

pulmonary first-pass perfusion

center-of-gravity method

cardiac output

noninvasive biomarker