Strain-encoding cardiovascular magnetic resonance for assessment of right-ventricular regional function

Background: Tissue tagging by cardiovascular magnetic resonance (CMR) is a comprehensive method for the assessment of cardiac regional function. However, imaging the right ventricle (RV) using this technique is problematic due to the thin wall of the RV relative to tag spacing which limits assessment of regional function using conventional in-plane tagging. Hypothesis: We hypothesize that the use of through-plane tags in the strain-encoding (SENC) CMR technique would result in reproducible measurements of the RV regional function due to the high image quality and spatial resolution possible with SENC. Aim: To test the intra- and inter-observer variabilities of RV peak systolic strain measurements with SENC CMR for assessment of RV regional function (systolic strain) in healthy volunteers. Methods: Healthy volunteers (n = 21) were imaged using SENC. A four-chamber view was acquired in a single breath-hold. Circumferential strain was measured during systole at six equidistant points along the RV free wall. Peak contraction is defined as the maximum value of circumferential strain averaged from the six points, and regional function is defined as the strain value at each point at the time of peak contraction. Results: Mean values for peak circumferential strain (± standard deviation) of the basal, mid, and apical regions of the RV free wall were -20.4 ± 2.9%, -18.8 ± 3.9%, and -16.5 ± 5.7%, Altman plots showed good intra- and inter-observer agreements with mean difference of 0.11% and 0.32% and limits of agreement of -4.038 to 4.174 and -4.903 to 5.836, respectively. Conclusion: SENC CMR allows for rapid quantification of RV regional function with low intraand inter-observer variabilities, which could permit accurate quantification of regional strain in patients with RV dysfunction.