title: Clinical Meaning of Hot Uptake on Bone Scan in Symptomatic Accessory Navicular Bones.
abstract: BACKGROUND
  We analyzed clinical factors related to uptake on a Tc-99 m HDP bone scan of the accessory navicular (AN).
  
  
  METHODS
  We retrospectively reviewed patients who had been examined by an orthopedic surgeon and underwent bone scan due to suspected symptomatic AN. A three-point grading system was used to evaluate uptake on bone scan. Relationships between grade, symptoms, age, gender, symptom duration, and bone size were analyzed.
  
  
  RESULTS
  In total, 73 ANs (30 asymptomatic, 43 symptomatic) were enrolled. The majority of asymptomatic ANs had no uptake but some had grade 1 (n= 8) or 2 (n= 2) uptake. All asymptomatic ANs with uptake remained asymptomatic during follow-up. For the asymptomatic ANs, larger bones showed a higher grade. With a cut-off value of size ≤6.8 mm, there is no chance of uptake. All symptomatic ANs showed uptake on bone scan. For symptomatic ANs, larger size and shorter pain duration were related to a higher grade. Age, gender, and left-/right-sideness were not related to grade. Multiple regressions revealed that only uptake grade, not size or symptom duration, was the significant risk factor for a symptomatic AN. With a cut-off value of grade <1, a symptomatic AN could be ruled out with a negative predictive value of 100 %.
  
  
  CONCLUSIONS
  Bone scanning is useful for symptomatic ANs with a high negative predictive value. Higher grade is related to larger size and shorter pain duration. For asymptomatic ANs, grade was related to size but did not predict symptom development.
authors.affiliation: Department of Nuclear Medicine, Chosun University Hospital, 588 Seoseok-dong, Dong-gu Gwangju, Republic of Korea 501-757.
authors.forename: Ari
authors.initials: A
authors.lastname: Chong
authors.affiliation: Department of Nuclear Medicine, Chosun University Hospital, 588 Seoseok-dong, Dong-gu Gwangju, Republic of Korea 501-757.
authors.forename: Jung-Min
authors.initials: JM
authors.lastname: Ha
authors.affiliation: Department of Orthopaedic Surgery, Foot and Ankle Surgery, Chosun University Hospital, Gwangju, Republic of Korea.
authors.forename: Jun-Young
authors.initials: JY
authors.lastname: Lee
keywords: Accessory navicular bone; Emission-computed; Radionuclide imaging; Tomography