LVtools workflow
Step 1 - Select images
The first step is to select a set of images to be used for the assessment. A stack of short axis cine images that provides complete temporal and spatial coverage of the left ventricle is required. In addition to this, two long axis cine images that pass through the mitral valve are required.
Step 2 - Identify apex
The second step is to identify the apex of the left ventricle. This enables the software to orientate the images correctly.
Step 3 - Add element
The third step allows the user to choose which element of the cardiac anatomy should be added to the model. Elements that can be added include the left ventricular myocardium and the blood pool.
Step 4 - Edit axis
For each element added to the model it is necessary to define an axis that passes through the ventricular blood pool. This can be performed by placing points in short axis views of the ventricle.
Step 5 - Edit surface
The surfaces of the ventricular model can be editing by clicking on anatomical boundaries within the images. As points are edited, the shape of the model is updated in 4 different views.
Step 6 - Threshold
LVtools allows the user to segment the blood pool from the myocardium by thresholding within the contours delineated by the user. Papillary muscles and trabeculations are included in the myocardial volume rather than in the blood pool volume.
Step 8 - Global assessment
LVtools allows the calculation of LV mass, volume, ejection fraction, and stroke volume. A graph is provided to show how the volume of the blood pool and myocardium change over the cardiac cycle.
Step 9 - Identify landmarks
In order to provide regional assessment of the ventricle, it is necessary for the user to identify the points of attachment between the right and left ventricular myocardium.
Step 10 - Regional assessment
LVtools provides the analysis of regional wall thickness and thickening. This information is displayed in a 17 segment model of the ventricle. The results can be exported to a spreadsheet for further analysis.
Step 7 - Track mitral valve
The motion of the mitral valve plane can be taken into account by allowing the user to define a dynamic plane that bisects the left ventricle from the left atrium. Both the mitral and the aortic valves can be modelled.
