Novel Approaches to Imaging the Pulmonary Vasculature and Right Heart

Abstract

There is an increased appreciation for the importance of the right heart and pulmonary circulation in several disease states across the spectrum of pulmonary hypertension and left heart failure. However, assessment of the structure and function of the right heart and pulmonary circulation can be challenging, due to the complex geometry of the right ventricle, comorbid pulmonary airways and parenchymal disease, and the overlap of hemodynamic abnormalities with left heart failure. Several new and evolving imaging modalities interrogate the right heart and pulmonary circulation with greater diagnostic precision. Echocardiographic approaches such as speckle-tracking and 3-dimensional imaging provide detailed assessments of regional systolic and diastolic function and volumetric assessments. Magnetic resonance approaches can provide high-resolution views of cardiac structure/function, tissue characterization, and perfusion through the pulmonary vasculature. Molecular imaging with positron emission tomography allows an assessment of specific pathobiologically relevant targets in the right heart and pulmonary circulation. Machine learning analysis of high-resolution computed tomographic lung scans permits quantitative morphometry of the lung circulation without intravenous contrast. Inhaled magnetic resonance imaging probes, such as hyperpolarized 129Xe magnetic resonance imaging, report on pulmonary gas exchange and pulmonary capillary hemodynamics. These approaches provide important information on right ventricular structure and function along with perfusion through the pulmonary circulation. At this time, the majority of these developing technologies have yet to be clinically validated, with few studies demonstrating the utility of these imaging biomarkers for diagnosis or monitoring disease. These technologies hold promise for earlier diagnosis and noninvasive monitoring of right heart failure and pulmonary hypertension that will aid in preclinical studies, enhance patient selection and provide surrogate end points in clinical trials, and ultimately improve bedside care.

The right ventricle systolic force ratio could predict the severity of the tricuspid regurgitation‐RIVIERA ratio

“…Over the past 20–25 years, cardiovascular magnetic resonance (CMR) has established itself as the gold standard for assessing left and right ventricular mass, volume, and function. Additionally, it has developed into a trustworthy and precise tool for calculating the volumetric quantification of the heart valves utilizing a number of methods that are independent of jet morphology 19–21 . When evaluating TR using an integrated strategy that considers both qualitative and quantitative parameters, echocardiography is the recommended and advised initial imaging technique.…”

“…Assessing valvular regurgitation with color Doppler involves measuring proximal isovelocity surface area (PISA) convergence method, vena contracta (VC), and TR the jet area. These well‐known and commonly used criteria do, however, have a number of drawbacks that should be taken into account 14–19 . For quantitative valve assessment, cardiac magnetic resonance imaging (CMR) frequently serves as gold standard 19–22 .…”

“…These well-known and commonly used criteria do, however, have a number of drawbacks that should be taken into account. [14][15][16][17][18][19] For quantitative valve assessment, cardiac magnetic resonance imaging (CMR) frequently serves as gold standard. [19][20][21][22] The ferromagnetic effects of metallic implants, claustrophobia, respiratory artifacts, arhythmia artifacts, claustrophobia, lack of technology in all centers, and a shortage of imaging professionals to interpret images are some of the drawbacks of CMR.…”

“…[14][15][16][17][18][19] For quantitative valve assessment, cardiac magnetic resonance imaging (CMR) frequently serves as gold standard. [19][20][21][22] The ferromagnetic effects of metallic implants, claustrophobia, respiratory artifacts, arhythmia artifacts, claustrophobia, lack of technology in all centers, and a shortage of imaging professionals to interpret images are some of the drawbacks of CMR. [19][20][21][22] Considering the unique disadvantages of the parameters mentioned earlier and the undeniable effect of severe TR on mortality, it can be speculated that the parameters obtained by using these parameters together can better define the severity of TR.…”

“…[19][20][21][22] The ferromagnetic effects of metallic implants, claustrophobia, respiratory artifacts, arhythmia artifacts, claustrophobia, lack of technology in all centers, and a shortage of imaging professionals to interpret images are some of the drawbacks of CMR. [19][20][21][22] Considering the unique disadvantages of the parameters mentioned earlier and the undeniable effect of severe TR on mortality, it can be speculated that the parameters obtained by using these parameters together can better define the severity of TR. It is essential to determine how much of the force generated by the RV during systole is spent on TR and how much is spent on the right ventricle outflow tract (RVOT) for stroke volume.…”