Abstract 15378: Changes in Fractal Dimension of the LV Endocardium During Systole Are Reduced in Myocardial Dysfunction.

Introduction: Assessment of regional cardiac function is important in the diagnosis and treatment of cardiac diseases such as myocardial ischemia, heart failure, and dyssynchrony. We present a method to leverage the high fidelity of x-ray CT to quantify regional LV function using temporal changes in the topography of the trabecular tissue across the cardiac cycle. Methods: Cine CT images of 14 subjects were acquired with standard clinical protocols. Based on a radiologist's clinical impression, ejection fraction, visual assessment of wall motion, and radial strain, 8 subjects were categorized as normal and 6 as abnormal. All abnormal subjects exhibited dysfunction in the mid-anterior and the mid-inferolateral segments. Regional topography characterization was measured by calculating the fractal dimension (FD) of the endocardium, from the segmented blood pool. The average FD within each of the 16 AHA segments was calculated for 20 time frames of the cardiac cycle. Normal from abnormal function was differentiated through principal component analysis of changes of FD over time (ΔFD). Results: Normal and abnormal subjects showed significantly different ΔFD values in the mid-anterior (0.14 ± 0.04 vs 0.04 ± 0.01, p < 0.0001) and the mid-inferolateral (0.15 ± 0.04 vs 0.05 ± 0.01, p < 0.0001) segments, reflecting differences in the changes in topography of the trabecular tissue during systole between the two cohorts. The principal component analysis of the time-varying FD revealed a distinction between normal and abnormal function. Conclusion: We developed a method to evaluate regional LV function from clinical cine CT images using the change in fractal dimension of the endocardial surface. The results from the study agreed with wall motion abnormalities seen on the cine CT images and with radial strain measurements. [ABSTRACT FROM AUTHOR]