Calculation of Cardiac Kinetic Energy Index from PET images.
Cardiac function can be assessed from displacement measurements in imaging modalities from nuclear medicine Using positron emission tomography (PET) image sequences with Rubidium-82, we propose and estimate the total Kinetic Energy Index (KEf) obtained from the velocity field, which was calculated using 3D optical flow(OF) methods applied over the temporal image sequence. However, it was found that the brightness of the image varied unexpectedly between frames, violating the constant brightness assumption of the OF method and causing large errors in estimating the velocity field. Therefore total brightness was equalized across image frames and the adjusted configuration tested with rest perfusion images acquired from individuals with normal (n=30) and low (n=33) cardiac function. For these images KEf was calculated as 0.5731±0.0899 and 0.3812±0.1146 for individuals with normal and low cardiac function respectively. The ability of KEf to properly classify patients into the two groups was tested with a ROC analysis, with area under the curve estimated as 0.906. To our knowledge this is the first time that KEf has been applied to PET images.
Division of Informatics, Heart Institute (InCor) Sao Paulo, Brazil.
John
J
Sims
Department of Nuclear Medicine and Molecular Imaging, Heart Institute (InCor) Sao Paulo, Brazil.
Marco Antônio
MA
Oliveira
Department of Nuclear Medicine and Molecular Imaging, Heart Institute (InCor) Sao Paulo, Brazil.
José Claudio
JC
Meneghetti
Division of Informatics, Heart Institute (InCor) Sao Paulo, Brazil.
Marco Antônio
MA
Gutierrez
D004735:Energy Transfer / Q000502:physiology*; D006352:Heart Ventricles / Q000000981:diagnostic imaging*; D006801:Humans; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods; D049268:Positron-Emission Tomography / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013318:Stroke Volume; D016277:Ventricular Function, Left / Q000502:physiology*