title: Pulmonary nodules in patients with primary malignancy: comparison of hybrid PET/MR and PET/CT imaging.
abstract: OBJECTIVE
  To assess diagnostic sensitivity of radial T1-weighted gradient-echo (radial volumetric interpolated breath-hold examination [VIBE]) magnetic resonance (MR) imaging, positron emission tomography (PET), and combined simultaneous PET and MR imaging with an integrated PET/MR system in the detection of lung nodules, with combined PET and computed tomography (CT) as a reference.
  
  
  METHODS
  In this institutional review board-approved HIPAA-compliant prospective study, 32 patients with tumors who underwent clinically warranted fluorine 18 ((18)F) fluorodeoxyglucose (FDG) PET/CT followed by PET/MR imaging were included. In all patients, the thorax station was examined with free-breathing radial VIBE MR imaging and simultaneously acquired PET data. Presence and size of nodules and FDG avidity were assessed on PET/CT, radial VIBE, PET, and PET/MR images. Percentage of nodules detected on radial VIBE and PET images was compared with that on PET/MR images by using generalized estimating equations. Maximum standardized uptake value (SUVmax) in pulmonary nodules with a diameter of at least 1 cm was compared between PET/CT and PET/MR imaging with Pearson rank correlation.
  
  
  RESULTS
  A total of 69 nodules, including 45 FDG-avid nodules, were detected with PET/CT. The sensitivity of PET/MR imaging was 70.3% for all nodules, 95.6% for FDG-avid nodules, and 88.6% for nodules 0.5 cm in diameter or larger. PET/MR imaging had higher sensitivity than PET for all nodules (70.3% vs 61.6%, P = .002) and higher sensitivity than MR imaging for FDG-avid nodules (95.6% vs 80.0%, P = .008). There was a significantly strong correlation between SUVmax of pulmonary nodules obtained with PET/CT and that obtained with PET/MR imaging (r = 0.96, P < .001).
  
  
  CONCLUSIONS
  Radial VIBE and PET data acquired simultaneously with PET/MR imaging have high sensitivity in the detection of FDG-avid nodules and nodules 0.5 cm in diameter or larger, with low sensitivity for small non-FDG-avid nodules.
authors.affiliation: Department of Radiology, New York University Langone Medical Center, 660 First Ave, New York, NY 10016, USA. hersh.chandarana@nyumc.org
authors.forename: Hersh
authors.initials: H
authors.lastname: Chandarana
authors.forename: Laura
authors.initials: L
authors.lastname: Heacock
authors.forename: Rajan
authors.initials: R
authors.lastname: Rakheja
authors.forename: Linda R
authors.initials: LR
authors.lastname: DeMello
authors.forename: John
authors.initials: J
authors.lastname: Bonavita
authors.forename: Tobias K
authors.initials: TK
authors.lastname: Block
authors.forename: Christian
authors.initials: C
authors.lastname: Geppert
authors.forename: James S
authors.initials: JS
authors.lastname: Babb
authors.forename: Kent P
authors.initials: KP
authors.lastname: Friedman
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000175:diagnosis* / Q000453:epidemiology*; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data*; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000706:statistics & numerical data*; D009518:New York / Q000453:epidemiology; D049268:Positron-Emission Tomography; D015995:Prevalence; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D003074:Solitary Pulmonary Nodule / Q000175:diagnosis* / Q000453:epidemiology*; D014057:Tomography, X-Ray Computed