Myocardial Strain Analysis using CMR Feature Tracking – The Good, The Bad and The Ugly
David Mui1, and Yuchi Han2
1Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
2Cardiovascular Division, Department of Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
Myocardial strain analysis has emerged as a valuable diagnostic and prognostic tool for cardiac disease detection and treatment. Currently, the gold standard for the non-invasive measurement of strain is using cardiovascular magnetic resonance imaging (CMR). While there are multiple ways to assess strain, including myocardial tagging (MT) and displacement encoding with stimulated echoes (DENSE), CMR feature-tracking (FT) has emerged as a simple post-processing tool for quantifying strain in large data sets. Because FT does not require acquisition of specific sequences, it has the ability to be used in large quantities of already acquired steady-state free procession (SSFP) cine images. However, despite its advantages, CMR FT also has numerous disadvantages. Acquisition-based techniques like MT and DENSE have better reproducibility in strain measurements than FT. FT is also limited by its spatial and temporal resolution as pixel size may affect the tracking of myocardial deformations. Furthermore, FT is limited by inter-vendor differences in the methods of calculating strain. Different vendors produce different strain values and there is currently no standardization of cine parameters or understanding of the performance of the different software with specific reference values. Future standardization of FT post-processing software must be implemented to interpret the results of FT in clinical and research settings.