title: Honda sign and variants in patients suspected of having a sacral insufficiency fracture.
abstract: OBJECTIVE
  The purpose of this study was to reassess whether the Honda sign (HS) and its variants on bone scans can be used to differentiate an insufficiency fracture (IF) of the sacrum from a metastasis and to evaluate extrapelvic tracer accumulation in patients suspected of having a sacral IF.
  
  
  METHODS
  We retrospectively reviewed 34 bone scans of 26 patients suspected of having a sacral IF between January 1998 and June 2003.
  
  
  RESULTS
  Twenty-four of the patients had a sacral IF and 1 had a sacral metastasis from prostate cancer and another from lung cancer. The bone scans of only 15 (63%) of the 24 patients with a sacral IF exhibited the HS, 8 (33%) scans exhibited variants, and 4 (4%) scans showed whole-sacrum uptake. One of the 2 patients with metastasis exhibited the HS and the other exhibited a variant. The sensitivity and positive predictive value of HS plus its variants as diagnostic criteria for sacral IF were 96% and 92%, respectively. Seventeen patients (71%) had extrasacral accumulation. The most common site was the pubic bone (50%, 12 of 24), and the second most common site was the spine (46%, 11 of 24), where the accumulation was the result of a compression fracture or degenerative joint disease of the spine.
  
  
  CONCLUSIONS
  A "Honda sign or variation" with evidence of fractures elsewhere or no evidence of other metastatic disease should be strong evidence for a sacral insufficiency fracture. The likelihood of having a solitary metastasis to the sacrum is small.
authors.affiliation: Department of Radiology, National Defense Medical College, Tokorozawa, Japan.
authors.forename: Manabu
authors.initials: M
authors.lastname: Fujii
authors.forename: Katsumi
authors.initials: K
authors.lastname: Abe
authors.forename: Katsumi
authors.initials: K
authors.lastname: Hayashi
authors.forename: Shigeru
authors.initials: S
authors.lastname: Kosuda
authors.forename: Fuzuki
authors.initials: F
authors.lastname: Yano
authors.forename: Sadahiro
authors.initials: S
authors.lastname: Watanabe
authors.forename: Shinako
authors.initials: S
authors.lastname: Katagiri
authors.forename: Wei Jey
authors.initials: WJ
authors.lastname: Ka
authors.forename: Shinichi
authors.initials: S
authors.lastname: Tominaga
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012447:Sacrum / Q000000981:diagnostic imaging* / Q000293:injuries* / Q000378:metabolism; D012680:Sensitivity and Specificity; D016103:Spinal Fractures / Q000000981:diagnostic imaging* / Q000378:metabolism; D013125:Spinal Neoplasms / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000556:secondary*; D013669:Technetium Tc 99m Medronate / Q000493:pharmacokinetics
chemical_list: D019275:Radiopharmaceuticals; D013669:Technetium Tc 99m Medronate