Effect of respiratory motion on quantitative myocardial gated SPECT: a simulation study
Ahmad Bitarafan-Rajabi1, Hossein Rajabi, Feridoon Rastgou
1Department of Medical Physics, School of Medical Sciences, Tarbiat Modares University, Tehran, Iran,. hrajabi@modares.ac.ir
Objective:
Respiratory motion is a potential cause of artefact and downgrading the quality of ECG-gated single photon emission computed tomography (SPECT) images that may result in clinical misinterpretation. We studied qualitatively the effects of respiratory motion on gated SPECT myocardial perfusion and function using Monte Carlo simulated data.
Methods:
NCAT phantom was used to model a human torso. The cardiac and respiratory cycles of torso were 1 and 5 s, respectively. Eight realizations of the phantom, having diaphragmatic motion amplitudes of 0-7 cm were generated. SimSET Monte Carol simulator was used to image the phantom and generate gated studies of 16 frames per cardiac cycle.
Results:
Our results demonstrated the underestimation of left ventricle end-diastolic, end-systolic, stroke volumes and ejection fraction and overestimation of wall motion and wall thickening (p < 0.01). In addition, the mean percentage of count in the basal-inferior, mid-inferior, apical-inferior, basal-septal and mid-septal segments were significantly lower due to respiratory motion when compared with control (p < 0.01). The changes in uptake were not significant in the apex, antroapical, apicoseptal, apicolateral, mid-anterior, basal-anterior, mid-lateral and basal-lateral segments.
Conclusion:
Respiratory motion has significant effect on the calculation of the left ventricular functional and regional myocardial perfusion in the GSPECT. The amount of deterioration and quality distortion of the images depends on the amplitude of the diaphragmatic motion.
