CMR-Flow

1349918 - Assessment of pulmonary hypertension with flow imaging in pulmonary artery

Wednesday, January 25, 2023

Location: E-POSTER

Presenting Author(s)

YL

Yu Y. Li, PhD

MRI Physicist & Research Associate Professor
St. Francis Hospital & Heart Center
Greenvale, New York, United States

Primary Author(s)

YL

Yu Y. Li, PhD

MRI Physicist & Research Associate Professor
St. Francis Hospital & Heart Center
Greenvale, New York, United States

Co-Author(s)

OO

Olufemi T. Olorunda, MD

Cardiac Imaging Fellow
St. Francis Hospital, United States
YC

Yang J. Cheng, RT

Chief MRI Technologist
St. Francis Hospital, The Heart Center
Greenvale, New York, United States
JC

J. Jane J. Cao, MD, MPH

Catholic System Research Director & Professor of Clinical Medicine
St. Francis Hospital, The Heart Center
Greenvale, United States

Background: Doppler echocardiography of the pulmonary artery (PA) flow has been found to be correlated with PA pressure (PAP) using PA flow acceleration time. Compared with echocardiography, CMR gives lower temporal resolution, making it difficult to detect peak flow precisely. However, CMR gives higher spatial resolution, providing an approach to quantifying geometric changes during ejection. The presented work aims to combine PA flow and geometry measurements from CMR to assess PAP.

Methods: Two CMR studies were conducted. In the first study, we prospectively recruited 52 patients that had undergone invasive hemodynamic testing for PAP and CMR with a phase contrast flow imaging of the PA within 5 hours. The PA cross-section area and the PA flow acceleration time were measured. The regression equation for calculating mean PAP was found to be 51 - 0.15 ´ (Acceleration time) ´ (Area ratio)², where the Area ratio was given by the ratio of the maximum PA area to the minimum PA area during a cardiac cycle. In the second CMR study, we prospectively recruited 24 healthy volunteers and 43 patients with PA hypertension secondary to chronic obstructive pulmonary disease (COPD) to undergo the same phase contrast flow imaging of the PA as in the first study. The mean PAP estimated from CMR were compared between the healthy volunteers and the COPD patients.

Results: The mean PAP assessed by acceleration time and area ratio had a stronger correlation with invasively assessed PAP (R=-0.81, p< 0.001) than by acceleration time alone (R=-0.63, p< 0.001) (Figure 1). The COPD patients were well differentiated from the healthy volunteers using the estimated mean PAP (28±2.0 mmHg vs 19±4.3 mmHg, p< 0.001) (Figure 2).

Conclusion: It is feasible to assess mean PAP using CMR flow imaging which may have the potential to quantitatively assess PA pressure for clinical evaluation of pulmonary hypertension.