Left Ventricular (LV) Linear Measures
Evaluating the size of key left ventricular (LV) features may facilitate determining whether the LV is functioning normally. The LV end-diastolic and end-systolic dimensions (EDD and ESD, respectively) are two common linear, echocardiographic measurements that are still used today by cardiologists to guide therapeutic decision making—e.g., about the timing of possible surgery. Although magnetic-resonance-imaging (MRI)-derived volumetric parameters are more accurate and have greater reproducibility, most cardiology guidelines have not yet incorporated these parameters into official guidelines. Consequently, it is helpful to provide LV EDD and ESD as part of the cardiac MRI exam. In echocardiography, the EDD and ESD measurements are usually made at the level of the papillary muscles on the 3-chamber view. However, in MRI analysis, these measurements are usually made on the short-axis view at the level of the papillary muscle tips (Fig.A-D). Specifically, LV EDD and ESD measurements are obtained by drawing a line measuring the distance between the anteroseptal and inferolateral walls (Fig.A-D).
In addition, linear measures of wall thickness are routinely made to assess for the presence of left ventricular hypertrophy (LVH) (Fig.A&B). Measurements of wall thickness at the anteroseptum and inferoseptum are only made at end diastole, so that the wall thickness is not attributed to myocardial contraction. As in echocardiography, these measures are made at the level of the papillary muscle tips (Fig.A&C). In cases of LVH, the maximum LV end-diastolic wall thickness is also reported along with its location. Importantly, wall thickness measurements should exclude trabeculations from both the LV and right ventricle.