title: Novel penalised likelihood reconstruction of PET in the assessment of histologically verified small pulmonary nodules.
abstract: OBJECTIVE
  Investigate the effect of a novel Bayesian penalised likelihood (BPL) reconstruction algorithm on analysis of pulmonary nodules examined with 18F-FDG PET/CT, and to determine its effect on small, sub-10-mm nodules.
  
  
  METHODS
  18F-FDG PET/CTs performed for nodule evaluation in 104 patients (121 nodules) were retrospectively reconstructed using the new algorithm, and compared to time-of-flight ordered subset expectation maximisation (OSEM) reconstruction. Nodule and background parameters were analysed semi-quantitatively and visually.
  
  
  RESULTS
  BPL compared to OSEM resulted in statistically significant increases in nodule SUVmax (mean 5.3 to 8.1, p < 0.00001), signal-to-background (mean 3.6 to 5.3, p < 0.00001) and signal-to-noise (mean 24 to 41, p < 0.00001). Mean percentage increase in SUVmax (%ΔSUVmax) was significantly higher in nodules ≤10 mm (n = 31, mean 73%) compared to >10 mm (n = 90, mean 42 %) (p = 0.025). Increase in signal-to-noise was higher in nodules ≤10 mm (224%, mean 12 to 27) compared to >10 mm (165%, mean 28 to 46). When applying optimum SUVmax thresholds for detecting malignancy, the sensitivity and accuracy increased using BPL, with the greatest improvements in nodules ≤10 mm.
  
  
  CONCLUSIONS
  BPL results in a significant increase in signal-to-background and signal-to-noise compared to OSEM. When semi-quantitative analyses to diagnose malignancy are applied, higher SUVmax thresholds may be warranted owing to the SUVmax increase compared to OSEM.
  
  
  CONCLUSIONS
  • Novel Bayesian penalised likelihood PET reconstruction was applied for lung nodule evaluation. • This was compared to current standard of care OSEM reconstruction. • The novel reconstruction generated significant increases in lung nodule signal-to-background and signal-to-noise. • These increases were highest in small, sub-10-mm pulmonary nodules. • Higher SUV max thresholds may be warranted when using semi-quantitative analyses to diagnose malignancy.
authors.affiliation: Department of Radiology, Churchill Hospital, Oxford University Hospitals NHS Trust, Old Road, Headington, Oxford, OX3 7LE, UK. eugene.teoh@oncology.ox.ac.uk.|Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK. eugene.teoh@oncology.ox.ac.uk.
authors.forename: Eugene J
authors.initials: EJ
authors.lastname: Teoh
authors.affiliation: Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK.|Radiation Physics and Protection, Churchill Hospital, Oxford University Hospitals NHS Trust, Old Road, Oxford, OX3 7LE, UK.
authors.forename: Daniel R
authors.initials: DR
authors.lastname: McGowan
authors.affiliation: Department of Radiology, Churchill Hospital, Oxford University Hospitals NHS Trust, Old Road, Headington, Oxford, OX3 7LE, UK.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Bradley
authors.affiliation: Department of Thoracic Surgery, John Radcliffe Hospital, Oxford University Hospitals NHS Trust, Headley Way, Oxford, OX3 7DU, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Belcher
authors.affiliation: Department of Thoracic Surgery, John Radcliffe Hospital, Oxford University Hospitals NHS Trust, Headley Way, Oxford, OX3 7DU, UK.
authors.forename: Edward
authors.initials: E
authors.lastname: Black
authors.affiliation: Department of Radiology, Churchill Hospital, Oxford University Hospitals NHS Trust, Old Road, Headington, Oxford, OX3 7LE, UK.|Department of Oncology, University of Oxford, Oxford, OX3 7DQ, UK.
authors.forename: Fergus V
authors.initials: FV
authors.lastname: Gleeson
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D001499:Bayes Theorem; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007091:Image Processing, Computer-Assisted / Q000379:methods*; D008168:Lung / Q000000981:diagnostic imaging; D008175:Lung Neoplasms / Q000000981:diagnostic imaging*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D012189:Retrospective Studies; D003074:Solitary Pulmonary Nodule / Q000000981:diagnostic imaging*; D014057:Tomography, X-Ray Computed; D055815:Young Adult
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18
keywords: Image quality enhancement; Image reconstruction; Positron-emission tomography; Signal-to-noise ratio; Solitary pulmonary nodule