Abstract
Patient motion degrades image-quality, affecting the quantitative assessment of PET-images. This affects studies of coronary lesions where micro-calcification processes are targeted. Coronary PET imaging protocols require up to 30-min scans, introducing the risk of gross patient motion (GPM) during the acquisition. Here, we investigate the feasibility of an automated data-driven method for detection of GPM during the PET-acquisition. Methods: Twenty-eight patients with stable coronary disease underwent a 30-min PET acquisition 1 hour after injection of 248±10 MBq 18F- Sodium Fluoride (NaF), followed by a coronary computed tomography angiography (CTA) scan. An automated data-driven GPM detection technique tracking the center-of-mass (CoM) of the count rates for every 200 milliseconds in the PET list-mode data was devised and evaluated. Two patient motion patterns were considered: sudden repositioning (motion >0.5 mm within 3 seconds) and general repositioning (motion >0.3 mm over 15 seconds or more). After reconstruction of diastolic images, individual GPM frames with focal coronary uptake were co-registered in 3D, creating a GPM-compensated (GPMC) image series. Lesion motion was reported for all lesions with focal uptake. Relative differences in maximum standard uptake value (SUVmax) and target to background ratio (TBR) between GPMC and non-GPMC (standard electrocardiogram gated data) diastolic PET images were compared in three separate groups defined by the maximum motion observed in the lesion (<5, 5-10 and >10 mm). Results: A total of 35 18F-NaF-avid lesions were identified in 28 patients. An average of 3.5±1.5 GPM frames were considered for each patient, resulting in an average frame duration of 7±4 (range, 3 – 21) min. Mean per-patient motion was: 7±3 mm (maximum 13.7 mm). GPMC increased SUVmax and TBR in all lesions with motion >5 mm. Lesions with 5-10 mm motion (N = 15) had SUVmax and TBR increased by 4.6±5.6% (P = 0.02) and 5.8±6.4% (p<0.002) respectively; lesions with motion ≥10 mm (N = 15) had SUVmax and TBR increased by 5.0±5.3% (P = 0.009) and 11.5±10.1% (P = 0.001) respectively. GPM correction led to diagnostic reclassification of 3 (11%) patients. Conclusion: GPM during coronary 18F-NaF PET-imaging is common and may affect the quantitative accuracy. An automated retrospective compensation of this motion is feasible and should be considered for coronary PET imaging.
- Cardiology (basic/technical)
- Image Reconstruction
- Instrumentation
- 18F-NaF
- Cardiac PET
- Data-driven motion detection
- Motion compensation
- PET/CT
- Copyright © 2018 by the Society of Nuclear Medicine and Molecular Imaging, Inc.