Evaluation of echocardiographic derived parameters for right ventricular size and function using cardiac magnetic resonance imaging.

Background: Cardiac Magnetic Resonance Imaging (cMRI) is the gold standard for right ventricular (RV) assessment due to its high spatial resolution. The American Society of Echocardiography (ASE) recommends eight structural and six functional quantitative parameters for evaluation of the RV. This study sought to simplify echocardiographic RV assessment by examining the relative diagnostic value of the echo recommended parameters by applying them to cMRI imaging of the RV.

Methods: We applied ASE recommended measures of RV size and function to 56 cMRI's and compared them to RV volumetric analysis obtained from cMRI. Pearsons' correlation coefficient was used to compare ASE prescribed parameters to corresponding cMRI calculated RV end diastolic volume (RVEDV) and RV ejection fraction (RVEF). The diagnostic performance of each parameter in predicting abnormal RV size or function was analyzed using receiver operator characteristic curves. Youden-J index was used to determine optimal sensitivity/specificity cut-points. Stepwise regression modeling was performed to identify measurements independently associated with RV size or RVEF.

Results: RV end diastolic area (RVEDA) correlated best with RVEDV (r = .76, p < 0.001) and RV fractional area change (RVFAC) correlated best with RVEF (r = .7, p < 0.001). The best ASE parameter for identifying RV dilatation was RVEDA (Youden-J index = .84), the optimal cutoff was 32.3 cm which yielded sensitivity/specificity of 84% and 100%, respectively. The best parameter for diagnosing RV dysfunction was RVFAC (Youden-J index = .52), with an optimal cutoff of 42% leading to sensitivity/specificity of 64% and 88%, respectively.

Conclusion: The area based echocardiographic parameters for RV size and function, RVEDA and RV fractional area change outperform linear measurements in predicting RV dilation and RV systolic dysfunction. These parameters should be examined in further echocardiographic based studies as the primary parameters to guide quantitative RV assessment.