Investigation of the effect of patient motion on myocardial perfusion SPECT imaging using cardiac phantom

Different directions and degrees of patient movement can occur during a SPECT study. The type and degree of patient movement may influence the presence and clinical importance of the resultant motion artifacts. The purpose of this investigation was to determine the relationship between the distance or the direction of movement and degree of motion artifact.The clinical significance of motion artifact was determined by interpreting images with quantitative bull's eye analysis using standardized criteria for abnormality. The study was performed using cardiac phantom which bearing 1,2x2x2 cm lesion. SPECT was acquired using 1 zoom factor, 64x64 matrix and 8 frames/cardiac cycle. No motion first imaging accepted as referece study. During the imaging the fantom was moved ±X ve ±Y directions from frame 8 to frame 16 as patient was moving. Movement of ±1 and ±2 cm caused a tolerable artifact when the motion occurred on the ±X and ±Y directions. Movement of greater than ±3 cm did not cause a detectable artifact. Motion artifact was more detectable with less distances of movement and when the movement occurred at the early images as compared to the ends of SPECT. Patient movement even if grater than ±3 cm at the ends of a study is less likely to result in image artifacts than movement in the middle or very beginning of an acquisition. Movement of greater than ±3 cm can cause clinically important image artifacts and must be considered as a potential source of error in tomographic myocardial perfusion studies.