title: Prevalence of incidental or unexpected findings on low-dose CT performed during routine SPECT/CT nuclear medicine studies.
abstract: BACKGROUND
  In nuclear medicine, single-photon-emission computed tomography (SPECT) is often combined with 'simultaneous' low-dose CT (LDCT) to provide complementary anatomical and functional correlation. As a consequence, numerous incidental and unexpected findings may be detected on LDCT. Recognition of these findings and appropriate determination of their relevance can add to the utility of SPECT/CT. We aimed to evaluate the prevalence and categorise the relevance of incidental and unexpected findings on LDCT scans performed as part of routine SPECT/CT studies.
  
  
  METHODS
  All available LDCT scans performed as part of SPECT/CT studies at St. Vincent's Hospital Melbourne in the year 2013 were retrospectively reviewed. Two qualified radiologists independently reviewed the studies and any previous available imaging and categorised any detected incidental findings.
  
  
  RESULTS
  A total of 2447 LDCT studies were reviewed. The relevance of the findings was classified according to a modified version of a scale used in the Colonography Reporting and Data System: E1 = normal or normal variant (28.0%); E2 = clinically unimportant (63.5%); E3 = likely unimportant or incompletely characterised (6.2%); E4 = potentially important (2.5%).
  
  
  CONCLUSIONS
  Imaging specialists need to be cognisant of incidental and unexpected findings present on LDCT studies performed as part of SPECT/CT. Appropriate categorisation of findings and communication of potentially important findings to referring clinicians should form part of routine practice. The overall prevalence of potentially significant incidental and unexpected findings in our series was 8.7% (E3, 6.2%; E4, 2.5%) and was comparable to rates in other published imaging series.
authors.affiliation: Medical Imaging Department, St Vincent's Hospital Melbourne, Melbourne, Victoria, Australia.
authors.forename: Kelvin Kwok-Ho
authors.initials: KK
authors.lastname: Yap
authors.forename: Ganesh
authors.initials: G
authors.lastname: Ramaseshan
authors.forename: Tom
authors.initials: T
authors.lastname: Sutherland
authors.forename: Raymond
authors.initials: R
authors.lastname: Shafik-Eid
authors.forename: Kim
authors.initials: K
authors.lastname: Taubman
authors.forename: Stephen
authors.initials: S
authors.lastname: Schlicht
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D033162:Incidental Findings; D008297:Male; D008875:Middle Aged; D064847:Multimodal Imaging / Q000379:methods / Q000706:statistics & numerical data*; D015995:Prevalence; D011829:Radiation Dosage; D011835:Radiation Protection / Q000379:methods / Q000706:statistics & numerical data*; D015203:Reproducibility of Results; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D017678:Sex Distribution; D015899:Tomography, Emission-Computed, Single-Photon / Q000379:methods / Q000706:statistics & numerical data*; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000706:statistics & numerical data*; D014739:Victoria / Q000453:epidemiology
keywords: SPECT/CT; computed tomography; incidental findings; scintigraphy