Phantom Evaluation of C-SPECT Performance for Myocardial Perfusion Imaging

Introduction: Myocardial Perfusion Imaging (MPI) remains a cornerstone of cardiovascular care with 8 million scans per year in the US. Relative to current SPECT technology, cardiac PET has improved sensitivity and specificity and allows for dynamic imaging and thus myocardial blood flow (MBF) quantification. Given growing awareness of the role of the coronary mirovasculature, the latter is particularly useful. Recently, several SPECT scanners have been developed that can acquire all lines of response simultaneously, trading a large Field of View (FOV) for multiple simultaneous projections of the cardiac region, potentially enabling fast dynamic scanning and MBF measurements in SPECT. C-SPECT is such a system with the additional capability of adaptive imaging, which allows for different resolution-sensitivity-FOV operating points. This can be used, for example, to switch between high-sensitivity mode for dynamic imaging and high-resolution mode for static imaging. In this study, we evaluate the capabilities of this novel system for identifying cardiac lesions in the high-resolution mode. Methods: We acquired high-count scans of emission data using an anthropomorphic torso phantom filled with aqueous 99mTc-pertechnetate for male and female configurations with torso, myocardium, and breast emission data acquired separately. The myocardium was acquired without a lesion and with four different positions each for six lesions. The projection data were mixed into ensembles in post-acquisition processing and reconstructed. Receiver Operating Characteristic (ROC) curves were determined and the areas under the ROC curves were determined. Results: The area under the ROC curve (AROC) was nearly 1 for all lesions imaged with 5-minute and 10-minute scans. The AROC for 2-minute scans varied by lesion location and decreased for females. Discussion: C-SPECT is very effective in identifying lesions, including focal subendocardial lesions for both male and female anatomy. The trends seen in the ROC curves for the 2-minute scans are consistent with expectations that lateral lesions were the easiest to identify and that additional attenuation and scatter in the female phantoms decreased image quality. Conclusions: C-SPECT is capable of reliably identifying cardiac lesions of varying severity in male and female phantoms using realistic background distributions for MPI down to scans of two minutes.