What the software can be used for
It is important that VentricularTools is only used to calculate myocardial mass, end-diastolic and end-systolic volume, ejection fraction and stroke volume from magnetic resonance images of the left ventricle in humans. The images used must be acquired using an approved hardware/software scanner combination. The software must be used in full accordance of the instructions outlined in this document.
What the software cannot be used for
VentricularTools must not be used to calculate parameters for any region of the body except the left and ventricle of the heart. Furthermore, the software must not be used to perform analysis in animals. Finally, the software must not be used to analyse images that have been acquired by any device other than a cardiovascular magnetic resonance scanner.
System requirements
VentricularTools requires a PC or a laptop running Microsoft Windows XP with a 1GHz processor, 512MB RAM, 128MB graphics card and 2GB of free hard disk space.
Operator requirements
VentricularTools must only be used by a person who has been professionally trained in medicine and human anatomy. In addition, the user should have prior experience of working with cardiovascular MR images in a clinical environment.
Image acquisition
VentricularTools must be used in conjunction with an approved combination of scanner hardware, software and scanning sequences. The person who operates the scanner must be professionally trained in magnetic resonance imaging of the heart. To perform an assessment of the left ventricle using VentricularTools, a set of short axis image slices that provides complete spatial coverage of the LV is required. These slices should be equally spaced and each should have the same field of view and pixel size. It is advised that a slice thickness less than 10mm is used with a pixel size less than 2mm x 2mm. It is acceptable to have small equal gaps between adjacent short axis image pairs as long as the total distance between slices is less than 10mm. Each short axis image series should provide complete temporal coverage of the cardiac cycle and have the same number of cardiac phases. It is acceptable that the different short axis image slices are acquired in separate breath-holds although care must be taken during scanning to ensure that excessive patient movement does not occur.
In addition to the short axis (SA) image stack, two long axis image series that pass through the mitral valve are required. One of these should be a horizontal long axis (HLA) image that passes through all four chambers of the heart. The other should be a vertical long axis (VLA) image that is perpendicular to this. The images below show the orientations of the slices required.
Important Information
VentricularTools is a software plug-in to CMRtools that allows the assessment of magnetic resonance (MR) images of the left ventricle ( LV). It permits the calculation of myocardial mass, end-diastolic and end-systolic volume, ejection fraction and stroke volume. These parameters are calculated from a patient-specific geometric model of the heart that is generated by the software and corrected by the user. A step-by-step graphical interface is provided that leads the user through a set of tasks. These tasks include loading images, selecting which images should be used within a study, identifying end-diastole and end-systole, identifying the apex of the left ventricle, delineating valve planes, drawing and correcting contours, thresholding the blood pool from the myocardium and finally calculating the cardiac indices.