Investigation of "hot air spot" artifact in integrated PET/MR examination / 中国医学影像技术

ABSTRACT

Objective: T To investigate the distribution and occurrence probability of artifact of "hot air spot" in integrated PET/MR examination, and the role of time of flight (TOF) in alleviating the artifact of "hot air spot ". Methods: The occurrence sites and probability of artifact of "hot air spot" in 105 examinees who underwent integrated whole-body PET/MR examination were retrospectively analyzed, and the occurrence of heat organ sign in integrated PET/MR without TOF technology and TOF-PET/MR images were evaluated. Results: The artifacts of "hot air spot" were distributed in sinus, trachea, gastric sinus, colon and rectum, and most commonly in trachea in the integrated PET/MR examination, and the incidence rates were 60.00%(63/105), 68.57%(72/105), 8.57%(9/105), 20.00%(21/105) and 16.19%(17/105), respectively. The SUVmax of different parts on PET/MR images without TOF technology were 4.09±2.17, 1.77±0.81,1.75±0.85,3.73±0.51 and 11.77±8.39, respectively. The SUVmean of different parts on integrated TOF-PET/MR images were 3.19±1.87, 1.38±0.70, 1.44±0.85, 2.68±0.46 and 6.78±4.19, respectively. The SUVmax and SUVmean of artifact of "hot air spot" on PET/MR images without TOF technology were higher than those on integrated TOF-PET/MR images (all P<0.01). Conclusion: The artifact of "hot air spot " mainly exists in the sinuses, trachea and digestive tract in integrated whole-body PET/MR examination. The artifact of "hot air spot" in the trachea is the most commonly happened among them. TOF technology can obviously help to reduce the "hot air spot" artifact on the integrated PET/MR examination without TOF technology, thus significantly improving the quality of the integrated PET/MR image.