Analysis of right ventricular mass from magnetic resonance imaging data: a simple post-processing algorithm for correction of partial-volume effects.

Background Magnetic resonance imaging (MRI) of the right ventricle (RV) offers important diagnostic information, but the accuracy of this information is hampered by the complex geometry of the RV. In this project, we propose a novel post-processing algorithm that corrects for partial-volume effects in the analysis of standard MRI cine images of RV mass (RVm), and evaluate the method in clinical and preclinical data. Methods Self-corrected RVm measurement was compared with conventionally measured RVm in 16 patients who showed different clinical indications for cardiac MRI, and in 17 Wistar rats with different degrees of pulmonary congestion. The rats were studied under isoflurane anaesthesia. To evaluate the reliability of the proposed method, the measured end-systolic and end-diastolic RVm were compared. Accuracy was evaluated by comparing preclinical RVm to ex-vivo RV weight (RVw). Results We found that use of the self-correcting algorithm improved reliability compared with conventional segmentation. For clinical data, the limits of agreement (LOAs) were -1.8±8.6g (self-correcting) vs. 5.8±7.8g (conventional) and coefficients of variation (CoVs) were 7.0% (self-correcting) vs. 14.3% (conventional). For preclinical data, LOAs were 21±45mg (self-correcting) vs. 64±89mg (conventional) and CoVs were 9.0% (self-correcting) and 17.4% (conventional). Self-corrected RVm also showed better correspondence with the ex vivo RVw: LOAs were -5±80mg (self-correcting) vs. 94±116mg (conventional) in end-diastole and -26±74mg (self-correcting) vs. 31±98mg (conventional) in end-systole. Conclusions The new self-correcting algorithm improves the reliability and accuracy of RVm measurements in both clinical and preclinical MRI. It is simple, easy to implement and does not require any additional MRI data.