Quantifying Left Ventricular Myocardial Mass
Cardiac magnetic resonance imaging acquires myocardial mass noninvasively and with high reproducibility and accuracy. Obtaining left ventricular (LV) myocardial mass is important in evaluating many forms of cardiac disease. It may provide critical prognostic information for individuals with hypertension, hypertrophic cardiomyopathy, and valvular and/or ischemic heart disease.
The mass may be determined manually or automatically using suiteHEART® software (“the software”). To determine the mass manually, gated short-axis, steady-state free precession (SSFP) images are acquired, and the LV is segmented into 8 mm slices. The desired cardiac phase(s) is selected (e.g., end diastole), and both the LV endocardium and epicardium on all slices are traced at the selected phase (F1). Next, the software employs an algorithm—based on Simpson’s rule for computing LV volume (F2)—and reports the mass (g) at the given phase(s). The mass may be indexed to the body surface area, but is not automatically reported as such. A similar approach is required to determine the mass automatically. The same segmented short-axis, SSFP series is acquired, and the desired cardiac phase(s) is selected. The software automatically traces the endo- and epicardial countours of the LV myocardium, calculating its mass at the selected phase(s). The mass of the papillary muscles may be included or excluded in the mass calculation (F1).