MARIAN: an analysis tool for the assessment of left ventricular function measured by velocity encoding MRI

Velocity encoding MRI is a new non-invasive technique for measuring cardiac blood flow velocities. Flow in the three directions of space can be measured during the entire heart cycle. However, the analysis of large amount of data obtained from this technique requires specialized computational software packages to provide physicians with efficient analysis tools. A data visualization software package named Magnetic Resonance Imaging Analyzer (MARIAN) was developed. This software package uses visualization, animation, analysis, and computational tools adapted to time series of cardiac MRI data files, all accessible through a sophisticated graphics user interface. MARIAN was used as a tool for the analysis of the left heart blood flow patterns in two groups of human subjects: ten volunteers and eight patients. The patients were diagnosed with incapacitating angina pectoris and previous left ventricular myocardial infarction. Vector plot animations of the left atrial flow were realized for all volunteer examinations. The temporal flow velocity profiles were sampled at the tips of the mitral leaflets and in the lumen of the right upper pulmonary vein, when possible. The isovolumic relaxation time (IVRT) was estimated. The following flow parameters were obtained from the velocity profiles: at the mitral valve, the early diastolic E-wave, the late diastolic A-wave, the time of occurrence of the E- and A- waves; at the right upper pulmonary vein, the systolic S-wave, the early diastolic D-wave and the reverse late diastolic R-wave. The results obtained were consistent with previous studies using similar MRI techniques. Compared to the control group, the patient group exhibited higher isovolumic relaxation time, a lower peak E-wave, and a lower D-wave. MARIAN thus provided a fast, efficient and accurate data visualization tool for the analysis of human data.