Semi-automatic thresholding of RV trabeculation improves repeatability and diagnostic value in suspected pulmonary hypertension

Alistair Macdonald; Mahan Salehi; Samer Alabed; Ahmed Maiter; Ze Ming Goh; Krit Dwivedi; Chris Johns; Marcella Cogliano; Faisal Alandejani; Robin Condliffe; James M Wild; David G Kiely; Pankaj Garg; Andrew J Swift

doi:10.3389/fcvm.2022.1037385

Semi-automatic thresholding of RV trabeculation improves repeatability and diagnostic value in suspected pulmonary hypertension

Front Cardiovasc Med. 2023 Jan 4:9:1037385. doi: 10.3389/fcvm.2022.1037385. eCollection 2022.

Authors

Alistair Macdonald^{1

2}, Mahan Salehi^{1

2}, Samer Alabed^{1

2

3}, Ahmed Maiter^{1

2}, Ze Ming Goh^{1

2}, Krit Dwivedi^{1

2}, Chris Johns¹, Marcella Cogliano¹, Faisal Alandejani¹, Robin Condliffe⁴, James M Wild¹, David G Kiely^{1

4}, Pankaj Garg⁵, Andrew J Swift^{1

3}

Affiliations

¹ Department of Infection, Immunity and Cardiovascular Disease, The University of Sheffield, Sheffield, United Kingdom.
² Department of Clinical Radiology, Sheffield Teaching Hospitals, Sheffield, United Kingdom.
³ INSIGNEO, Institute for in Silico Medicine, The University of Sheffield, Sheffield, United Kingdom.
⁴ Sheffield Pulmonary Vascular Disease Unit, Royal Hallamshire Hospital, Sheffield, United Kingdom.
⁵ Norwich Medical School, University of East Anglia, Norwich, United Kingdom.

Abstract

Objectives: Right ventricle (RV) mass is an imaging biomarker of mean pulmonary artery pressure (MPAP) and pulmonary vascular resistance (PVR). Some methods of RV mass measurement on cardiac MRI (CMR) exclude RV trabeculation. This study assessed the reproducibility of measurement methods and evaluated whether the inclusion of trabeculation in RV mass affects diagnostic accuracy in suspected pulmonary hypertension (PH).

Materials and methods: Two populations were enrolled prospectively. (i) A total of 144 patients with suspected PH who underwent CMR followed by right heart catheterization (RHC). Total RV mass (including trabeculation) and compacted RV mass (excluding trabeculation) were measured on the end-diastolic CMR images using both semi-automated pixel-intensity-based thresholding and manual contouring techniques. (ii) A total of 15 healthy volunteers and 15 patients with known PH. Interobserver agreement and scan-scan reproducibility were evaluated for RV mass measurements using the semi-automated thresholding and manual contouring techniques.

Results: Total RV mass correlated more strongly with MPAP and PVR (r = 0.59 and 0.63) than compacted RV mass (r = 0.25 and 0.38). Using a diagnostic threshold of MPAP ≥ 25 mmHg, ROC analysis showed better performance for total RV mass (AUC 0.77 and 0.81) compared to compacted RV mass (AUC 0.61 and 0.66) when both parameters were indexed for LV mass. Semi-automated thresholding was twice as fast as manual contouring (p < 0.001).

Conclusion: Using a semi-automated thresholding technique, inclusion of trabecular mass and indexing RV mass for LV mass (ventricular mass index), improves the diagnostic accuracy of CMR measurements in suspected PH.

Keywords: cardiac MRI; diagnosis; pulmonary hypertension; right ventricle; trabeculation.

Abstract

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