An observer performance study of the effect of using the body contour in reconstructing cardiac SPECT images from truncated projection data

Truncation in the projection data generates artifacts in reconstructed images that degrade image quality and affect clinical diagnosis. However, these artifacts can be substantially reduced when the body contour is used as support in iterative reconstructions. By employing observer performance studies, the effect on myocardial defect detection in truncated fan-beam Tl-201 attenuation compensated SPECT images with and without using the body contour as support was evaluated. Two observer performance studies were carried out. In the first study the images were reconstructed without using the body contour, whereas in the second one the exact body contour was used. The results of the ROC analysis indicate that when the body contour is not used, severe truncation can have a notable effect on myocardial defect detection in attenuation compensated images. This effect is reduced when the body contour is used as support in reconstructing the attenuation map and the SPECT images.