Comparison between 180° and 360° acquisition arcs with and without correction by Ct-based attenuation maps in normal hearts at rest

Objective To investigate the effect of acquisition arc (180° or 360°) and attenuation correction (AC), in artifact occurrence and image uniformity of myocardial perfusion SPECT studies in normal hearts. Methods Twenty male and 44 female patients with primary hyperparathyroidism and low probability of resting perfusion abnormalities were analysed. 99mTc-sestamibi myocardial perfusion studies were performed at rest with a hybrid SPECT/CT system. An anthropomorphic phantom was also imaged. Results Without AC, a 360° orbit resulted in significantly lower artifact rates compared to the standard 180° in both gender groups. Differences persisted (P Conclusion Without AC there is significant disparity between 180° and 360° concerning artifact occurrence. After CT-based AC differences between arcs in defect rate and image uniformity seem less critical. However, 180° is favoured by less intensification of intestinal activity.