title: Imaging quality of F-18-FDG PET/CT in the inpatient versus outpatient setting.
abstract: OBJECTIVE
  The purpose of this study is to investigate potential differences in the image quality of inpatient versus outpatient F-18-FDG PET/CT to provide evidence for appropriate policies and procedures to be promulgated on inpatient referrals.
  
  
  METHODS
  100 consecutive inpatient and 100 outpatient F-18-FDG PET/CT scans were compared from the same time period and PET/CT scanner. Each study was evaluated for a subjective overall rating (optimal vs. suboptimal), and also by objective measurements (SUVmean) in four background structures (brain, blood pool, liver, and muscle).
  
  
  RESULTS
  96 outpatient scans were rated optimal and 4 suboptimal whereas corresponding numbers for inpatient scans were 77 and 23 (p < 0.001). Of the objective indices, cerebellar SUV was significantly different in inpatient versus outpatient (5.3 vs. 6.9; p < 0.001) as well as suboptimal versus optimal rated groups (4.8 vs. 6.3; p < 0.001). While mean blood glucose was higher for inpatients (108.01 vs. 101.49 mg/dl; p = 0.017), it was not significantly different between optimal and suboptimal exams. Linear regression analysis between blood glucose levels and cerebellar uptake revealed an inverse relationship (R = -0.38, p < 0.001).
  
  
  CONCLUSIONS
  There was a significantly higher number of inpatient PET/CT scans rated as suboptimal in comparison to outpatient scans. Decreased cerebellar uptake was present in suboptimal rated studies and in inpatient studies. Altered biodistribution is thus a potential etiology of reduced scan quality among inpatients. These findings, if duplicated among other readers and centers, may form the basis of quality control recommendations for inpatient PET/CT ordering patterns.
authors.affiliation: Department of Radiology, Emory University Hospital, Atlanta, GA, USA. sean.yan.x.x@sgh.com.sg
authors.forename: Xuexian
authors.initials: X
authors.lastname: Yan
authors.forename: Jian
authors.initials: J
authors.lastname: Kang
authors.forename: Yanli
authors.initials: Y
authors.lastname: Zhou
authors.forename: Ramisa
authors.initials: R
authors.lastname: Ehsan
authors.forename: Raghuveer
authors.initials: R
authors.lastname: Halkar
authors.forename: Kimberly E
authors.initials: KE
authors.lastname: Applegate
authors.forename: David M
authors.initials: DM
authors.lastname: Schuster
mesh_terms: D000553:Ambulatory Care; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D007297:Inpatients; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods*; D049268:Positron-Emission Tomography / Q000379:methods*; D011786:Quality Control; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D019788:Fluorodeoxyglucose F18