Cardiac gated equilibrium radionuclide angiography and multiharmonic Fourier phase analysis: Optimal acquisition parameters in arrhythmogenic right ventricular cardiomyopathy

BACKGROUND: Multiharmonic Fourier phase analysis of radionuclide angiography is a well-established method for the diagnosis of arrhythmogenic right ventricular cardiomyopathy. We sought to determine the optimal acquisition parameters: number of frames per cycle and number of counts per frame, with all other acquisition and processing parameters being fixed. METHODS AND RESULTS: Radionuclide angiography with list mode acquisition was performed in 10 normal subjects (pilot group) and 11 patients with arrhythmogenic right ventricular cardiomyopathy (validation group), allowing the reconstruction of electrocardiography-gated constant phase studies with different parameters: 16, 24, and 32 frames per cycle and 200, 400, 600, and 800 kcounts per frame. Three harmonics Fourier phase analysis was applied, and optimal acquisition parameters (defined as those providing best homogeneous phase distribution histogram in the pilot group) were defined as judged by the H3 right ventricular phase SD and delta 95%. These were 16 frames per cycle and 600 kcounts per frame. Then we verified in the validation group that these optimal acquisition parameters did not induce any significant relative loss of information compared with other acquisition parameters with more temporal resolution (24 and 32 frames per cycle) or more statistics (800 kcounts per frame). This result was realized by the calculation of normalized H3 right ventricular SD, right ventricular delta 95%, and (SD[left ventricle] - SD[right ventricle]). CONCLUSIONS: In practice, 16 frames per cycle and 600 kcounts per frame are optimal for multiharmonic Fourier phase analysis, with all other acquisition and processing variables being fixed as specified.