Abstract 697: New Simplified Method for Detailed Quantification of Regional Myocardial Function From Untagged MRI Cine Recordings: Radial Strain Mapping by Multimodality Tissue Tracking (MTT)
Background: Assessment of regional myocardial function is clinically important. Circumferential strain analysis by tagged MRI is considered the reference method, despite its complexity. We introduce radial strain mapping by multimodality tissue tracking (MTT) of untagged MRI cines as a new simplified method for detailed quantification of regional LV function. To validate our approach radial strain was compared to measures of circumferential strain by tagged MRI and to infarct transmurality by contrast MRI.
Methods: In patients revascularized after myocardial infarction (n=20) and in healthy subjects (n=8), radial strain was quantified in 12 LV midventricular segments by MTT from untagged MRI short-axis recordings (Figure 1⇓). MTT is a pixel-based pattern matching technique that allows automated tracking of endo- and epicardial border features. Circumferential strain and infarct transmurality was quantified by tagged- and contrast MRI, respectively.
Results: Mean radial strain was significantly lower in patients compared to healthy subjects (10.6±10.3 vs. 33.5±12.8%, P<0.0001, respectively). In a linear mixed model analysis, myocardial infarct extent was a strong predictor of radial strain (β= 0.13, P<0.00001). Radial strain could differentiate between remote, non-infarcted and infarcted border zone, and infarct centre segments (P<0.001). In a 6-segment analysis, there was an inverse relationship between circumferential strain by tagged- and radial strain by untagged MRI (r=0.70, P<0.0001; Figure 1⇓).
Conclusion: We have demonstrated that radial strain mapping of untagged MRI by MTT is a simple new clinical method for detailed quantification of LV function.