High-frame-rate tissue harmonic imaging enhances anatomic M-mode sections of the left ventricle in short-axis view

Background: High-frame-rate echocardiography (HFRE) and tissue harmonic ima ging (THI) may improve image quality, thereby enabling anatomic M-mode sect ions of left ventricular (LV) wall segments to be visualized in various pla nes in the short-axis view. Objectives: The goals of this study were to compare image quality between H FRE and conventional-frame-rate echocardiography (CFRE) and between fundame ntal imaging (FI) and THI, and to obtain anatomic M-mode values of basal sh ort-axis LV segments from healthy subjects for use in the evaluation of abn ormal segments in patients with myocardial Infarction (MI). Methods and Results: The study included 28 healthy subjects and 15 patients with MI who underwent 2-dimensional echocardiography with an ultrasonograp hic system equipped with THI and anatomic M-mode. Left ventricular image ci neloops at the basal short-axis view that were obtained with 3 combinations of imaging techniques (FI + CFRE, FI + HFRE, and THI + HFRE) were digitize d and displayed side-by-side in random order for comparison by blinded read ers. M-mode sections were done in 3 planes: anteroseptal-posterior, inferos eptal-lateral, and anterior-inferior basal segments. The THI + HFRE combina tion showed the best image quality with significant reduction in noise arti facts, resulting in a good signal-to-noise ratio and good tractability of a ll LV segments by anatomic M-mode. In healthy subjects, significant interse gmental differences existed In the diastolic and systolic thicknesses and I n the percent systolic thickening of LV segments. In patients with MI, LV s ystolic thickening was significantly decreased In abnormal segments. No sig nificant differences were noted in ejection fraction and fractional shorten ing among the 3 anatomic M-mode planes. Conclusion: High-frame-rate tissue harmonic imaging improved Image quality, thereby allowing reproducible anatomic M-mode measurements in various plan es in the short-axis view and providing a convenient objective evaluation o f global and regional LV function.