Determination of transmural, endocardial, and epicardial radial strain and strain rate from phase contrast MR velocity data

PURPOSE: To develop a method for computing radial strain (epsilon) and strain rate (SR) from phase contrast magnetic resonance (PCMR) myocardial tissue velocity data. MATERIALS AND METHODS: PCMR tissue velocity maps were acquired at basal and mid-short-axis slices in the myocardium in 10 healthy volunteers. An algorithm for computing radial strain and SR from PCMR tissue velocity data was developed. PCMR strain values were compared to values computed independently from contours drawn on cine steady-state free procession (SSFP) images. Peak endocardial and epicardial strain and SR values from PCMR data were compared. RESULTS: Excellent agreement was observed between peak strain values computed by PCMR and cine SSFP contours (38.1 +/- 5.4% vs. 38.1 +/- 6.2%; P = not significant NS). The presence of an endocardial-epicardial gradient was demonstrated in both strain and SR: peak endocardial values were larger than peak epicardial values in the basal and mid-short-axis slices (P < 0.05). CONCLUSION: This study presents a method for determining radial strain and SR values from PCMR velocity data. This technique illustrates a difference in strain and SR across the myocardium with peak endocardial values being greater than peak epicardial values.