title: Intramedullary spinal cord metastases: visibility on PET and correlation with MRI features.
abstract: OBJECTIVE
  Studies systematically evaluating the detection of intramedullary spinal cord metastasis with PET are lacking. Our purpose was to evaluate the visibility of intramedullary spinal cord metastasis on PET in a single institutional series and to correlate PET and MR imaging features.
  
  
  METHODS
  Patients were included if pretreatment MR imaging identifying an intramedullary spinal cord metastasis and an [(18)F] FDG-PET examination near the time of MR imaging were available. PET examinations were retrospectively reviewed, with reviewers blinded and then unblinded to the PET report and MR imaging findings. PET intramedullary spinal cord metastasis features were compared with and correlated with previously analyzed MR imaging lesion characteristics. Original clinical PET reports were reviewed.
  
  
  RESULTS
  The final study sample was 10 PET examinations in 10 patients with 13 intramedullary spinal cord metastases. In 7 (70%) patients, retrospective blinded review demonstrated convincing evidence of 10 (77%) intramedullary spinal cord metastases. Three MR imaging features correlated with intramedullary spinal cord metastases being visible on PET compared with those nonvisible, respectively: larger lesion enhancement size: mean size: 32.1 mm versus 6.0 mm (P = .038); larger longitudinal extent of T2 signal abnormality: mean 5.6 versus 1.0 segments (P = .0081); and larger ratio of extent of T2 signal abnormality to contrast enhancement: 3.8 versus 1.0 (P = .0069). Intramedullary spinal cord metastasis was confidently reported clinically in 2 (20%) patients, accounting for 5 (38%) intramedullary spinal cord metastases.
  
  
  CONCLUSIONS
  Most intramedullary spinal cord metastases can be detected on PET when performed near the time of pretreatment MR imaging. However, intramedullary spinal cord metastases may not be clinically reported on PET. Larger lesions with more edema are more likely to be visible. The spinal cord should be specifically and carefully assessed on PET for evidence of intramedullary spinal cord metastases to provide timely diagnosis.
authors.affiliation: Mayo Medical School.
authors.forename: P M
authors.initials: PM
authors.lastname: Mostardi
authors.forename: F E
authors.initials: FE
authors.lastname: Diehn
authors.forename: J B
authors.initials: JB
authors.lastname: Rykken
authors.forename: L J
authors.initials: LJ
authors.lastname: Eckel
authors.forename: K M
authors.initials: KM
authors.lastname: Schwartz
authors.forename: T J
authors.initials: TJ
authors.lastname: Kaufmann
authors.forename: C P
authors.initials: CP
authors.lastname: Wood
authors.forename: J T
authors.initials: JT
authors.lastname: Wald
authors.forename: C H
authors.initials: CH
authors.lastname: Hunt
mesh_terms: D000328:Adult; D000368:Aged; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D049268:Positron-Emission Tomography / Q000379:methods*; D019275:Radiopharmaceuticals; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D016037:Single-Blind Method; D013120:Spinal Cord Neoplasms / Q000175:diagnosis* / Q000556:secondary*; D013223:Statistics as Topic
chemical_list: D019275:Radiopharmaceuticals; D019788:Fluorodeoxyglucose F18