European Journal of Nuclear Medicine and Molecular Imaging | 2019
Triple-gated motion and blood pool clearance corrections improve reproducibility of coronary 18F-NaF PET
Abstract
To improve the test–retest reproducibility of coronary plaque 18F-sodium fluoride (18F-NaF) positron emission tomography (PET) uptake measurements. We recruited 20 patients with coronary artery disease who underwent repeated hybrid PET/CT angiography (CTA) imaging within 3 weeks. All patients had 30-min PET acquisition and CTA during a single imaging session. Five PET image-sets with progressive motion correction were reconstructed: (i) a static dataset (no-MC), (ii) end-diastolic PET (standard), (iii) cardiac motion corrected (MC), (iv) combined cardiac and gross patient motion corrected (2 × MC) and, (v) cardiorespiratory and gross patient motion corrected (3 × MC). In addition to motion correction, all datasets were corrected for variations in the background activities which are introduced by variations in the injection-to-scan delays (background blood pool clearance correction, BC). Test–retest reproducibility of PET target-to-background ratio (TBR) was assessed by Bland–Altman analysis and coefficient of reproducibility. A total of 47 unique coronary lesions were identified on CTA. Motion correction in combination with BC improved the PET TBR test–retest reproducibility for all lesions (coefficient of reproducibility: standard\u2009=\u20090.437, no-MC\u2009=\u20090.345 (27% improvement), standard + BC\u2009=\u20090.365 (20% improvement), no-MC\u2009+\u2009BC\u2009=\u20090.341 (27% improvement), MC\u2009+\u2009BC\u2009=\u20090.288 (52% improvement), 2 × MC\u2009+\u2009BC\u2009=\u20090.278 (57% improvement) and 3 × C\u2009+\u2009BC\u2009=\u20090.254 (72% improvement), all p\u2009<\u20090.001). Importantly, in a sub-analysis of 18F-NaF-avid lesions with gross patient motion > 10 mm following corrections, reproducibility was improved by 133% (coefficient of reproducibility: standard\u2009=\u20090.745, 3 × MC\u2009=\u20090.320). Joint corrections for cardiac, respiratory, and gross patient motion in combination with background blood pool corrections markedly improve test–retest reproducibility of coronary 18F-NaF PET.