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Updated: Sep 5, 2025
Evaluation of Right Ventricular Function in Experimental Models of Pulmonary Arterial Hypertension
Published on: June 27, 2025
Quantitative Assessment of Regional Pulmonary Transit Times in Pulmonary Hypertension
Jackson E Moore1,2, John W Cerne1, Ashitha Pathrose1
1Department of Radiology, Northwestern University, Chicago, Illinois, USA.
Background:
Pulmonary hypertension (PH) contributes to restricted flow through the pulmonary circulation characterized by elevated mean pulmonary artery pressure acquired from invasive right heart catheterization (RHC). MRI may provide a noninvasive alternative for diagnosis and characterization of PH.
Purpose:
To characterize PH via quantification of regional pulmonary transit times (rPTT).
Study Type:
Retrospective.
Population:
A total of 43 patients (58% female); 24 controls (33% female). RHC-confirmed patients classified as World Health Organization (WHO) subgroups 1-4.
Field Strength/Sequence:
A 1.5 T/time-resolved contrast-enhanced MR Angiography (CE-MRA).
Assessment:
CE-MRA data volumes were combined into a 4D matrix (3D resolution + time). Contrast agent arrival time was defined as the peak in the signal-intensity curve generated for each voxel. Average arrival times within a vessel region of interest (ROI) were normalized to the main pulmonary artery ROI (t0 ) for eight regions to define rPTT for all subjects. Subgroup analysis included grouping the four arterial and four venous regions. Intraclass correlation analysis completed for reproducibility.
Statistical Tests:
Analysis of covariance with age as covariate. A priori Student's t-tests or Wilcoxon rank-sum test; α = 0.05. Results compared to controls unless noted. Significant without listing P value. ICC ran as two-way absolute agreement model with two observers.
Results:
PH patients demonstrated elevated rPTT in all vascular regions; average rPTT increase in arterial and venous branches was 0.85 ± 0.15 seconds (47.7%) and 1.0 ± 0.18 seconds (16.9%), respectively. Arterial rPTT was increased for all WHO subgroups; venous regions were elevated for subgroups 2 and 4 (group 1, P = 0.86; group 3, P = 0.32). No significant rPTT differences were found between subgroups (P = 0.094-0.94). Individual vessel ICC values ranged from 0.58 to 0.97.
Data Conclusion:
Noninvasive assessment of PH using standard-of-care time-resolved CE-MRA can detect increased rPTT in PH patients of varying phenotypes compared to controls.
Level Of Evidence:
1 TECHNICAL EFFICACY: Stage 3.
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