Radionuclide ventriculography: evaluation of parameters of right ventricular function in healthy persons

The aim of study was to establish own method of assessment of right ventricular (RV) function and to calculate the normal values of ejection fraction and other parameters of emptying and filling of the RV from gated radionuclide ventriculography. Twenty-three patients (14 men, 9 women; mean age 31 y; range 21-69 y) were selected from the patients with excluded valve diseases and with low-to-medium probability of coronary artery disease, directed to a myocardial perfusion SPECT study. Criteria of inclusion to normalgroup: 1) lack of perfusion defects in SPECT study, and 2) normalright ventricular function in gated radionuclide ventriculography (significant increase of the RV ejection fraction in stress in comparison to rest). Gated radionuclide ventriculography was performed after in vivo labelling of the red blood cells with 99mTc, in modified LAO-45 projection (24 frames during heart cycle, 6-mln-counts acquisition in rest and then 3-min-long acquisitions on each level of exercise). 1) Analysis of RV function turned out difficult because of irregular shape of the ventricle and superposition of extra-ventricular structures (right atrium, pulmonary artery, left ventricle). 2) During RV contour drawing: a) the application of the amplitude and phase Fourier analysis helped to separate the activity corresponding to right atrium and left ventricle, b) the display of the heart in many different colour scales helped to establish the best separation between RV and pulmonary artery. 3) Normal values of the RV function achieved in rest: EF- RV=41±4%, PER - V=1.56±0.25[EDV/s], AER - RV=1.3±0.18[EDV/s], tPER - RV=102±29[ms], PFR - RV=1.24±0.27[EdV/s], AFR - RV=0.96±1.19[EDV/s, tPFR - RV=135±61[ms]. 4) Normal values achieved during maximal ±exercise: EF - RV=49±4%, PER - RV=3.17±0.73[[EDV/s, AER - RV=2.42±0.45[EDV/s, tPER -RV=82±23[ms], PFR - RV=3.47±0.73[EDV/s], AER - RV=2.24±0.64[EDV/s], tPFR - RV=124±28[ms]. In gated radionuclide ventriculography: 1) Normal values of the ejection fraction are significantly lower for the right ventricle than for the left ventricle - in rest and stress. 2) Nuclear medicine laboratory performing evaluation of RV should use own normal values for the ejection fraction and other emptying/filling parameters corresponding to own software and own approach to separation of extra-right ventricle structures, especially pulmonary artery. (author)