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 18 F-sodium fluoride (18 F-NaF) positron emission tomography (PET) uptake measurements. Methods 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 using all the data (no-MC), (ii) end-diastolic PET (Standard), (iii) cardiac motion corrected (MC), (iv) combined cardiac and gross patient motion corrected (2xMC) and, (v) cardiorespiratory and gross patient motion corrected (3xMC). 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. Results 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 = 0.437, No-MC = 0.345 (27% improvement), Standard+BC = 0.365 (20% improvement), no-MC+BC = 0.341 (27% improvement), MC+BC = 0.288 (52% improvement), 2xMC+BC = 0.278 (57% improvement) and 3xMC+BC = 0.254 (72% improvement), all p<0.001). Importantly in a sub analysis of 18 F-NaF-avid lesions with gross patient motion >10mm following corrections reproducibility was improved by 133% (coefficient of reproducibility: standard= 0.745, 3xMC= 0.320). Conclusion Joint corrections for cardiac, respiratory and gross patient motion in combination with background blood pool corrections markedly improve test-retest reproducibility of coronary 18 F-NaF PET.

Atherosclerosis Imaging with 18F-Sodium Fluoride PET

“…Most centers calculated a TBR using SUVmax and/or SUVmean values divided by blood pool activity from various parts of the vascular bed, even if recorded activity varies considerably from segment to segment of the vascular bed dependent on spill-over from NaF content in adjacent bone [ 40 ]. Cardiac motion was addressed in particular by Kwiecinski et al, who measured the uptake in the proximal parts of the coronary arteries [ 41 , 42 ], which others have found to be suboptimal due to the limited spatial resolution of PET imaging and cardiac and respiratory movements [ 43 ]. Instead, a global assessment approach comprising the entire heart may be preferable [ 4 , 44 ], and perhaps a better reflection of cardiac atherosclerosis burden as a clinically more relevant measure than the NaF uptake in vulnerable coronary plaques [ 45 , 46 ].…”

Atherosclerosis imaging with 18F-sodium fluoride PET: state-of-the-art review

“…Nonetheless, a number of observations, listed below, may hold true, whereas other questions remain unanswered. Most 2019 papers on NaF-PET imaging focus on unstable or what is designated vulnerable plaque morphology and detection in predominantly the coronary arteries often employing advanced methodologies [49,56,[58][59][60][61][62][63]. In August 2019, the first study on the efficacy of therapy judged by NaF-PET imaging appeared.…”

Estimation of optimal number of gates in dual gated 18F-FDG cardiac PET

“…For the patient study, the motion derived from models (1) and (2) was used as input for (3) and 4, and the optimal number of gates for each patient was determined. For determining the respiratory and pulsatile motion separately, model (1) was used.…”