title: Calcification of the trochlear apparatus of the orbit: CT appearance and association with diabetes and age.
abstract: OBJECTIVE
  Calcification can sometimes be observed on CT scans in the region of the trochlear apparatus of the orbit, the cartilaginous structure through which the superior oblique tendon and its sheath pass. We evaluated associations of trochlear calcifications with age and diabetes.
  
  
  METHODS
  We retrospectively reviewed CT scans of the orbit in 159 patients to identify the presence of trochlear calcifications. The presence or absence of diabetes, duration of diabetes, type of therapy, and presence or absence of neuropathy were determined from medical charts of 139 patients. We calculated the odds ratio of detecting a trochlear calcification and used logistic regression to evaluate the associations of age, sex, and diabetes with trochlear calcification.
  
  
  RESULTS
  Trochlear calcifications were present in seven of the 24 diabetic patients and in 10 of the 115 nondiabetic patients. The odds ratio for detecting trochlear calcifications in diabetic vs nondiabetic patients was 4.3 (p < .01). Logistic regression showed univariate associations with trochlear calcification for both increasing age (p < .001) and diabetes mellitus (p < .01). The effect of diabetes on the prevalence of trochlear calcifications was seen predominantly in those less than 40 years old (odds ratio = 24.0, p = .014). Sex, duration of diabetes, insulin dependence, and neuropathy were not significantly associated with an increase in trochlear calcifications.
  
  
  CONCLUSIONS
  The results show that a trochlear calcification seen on CT is a benign condition that may serve as a marker for diabetes in young patients. Trochlear calcifications are observed frequently (25-30%) in persons more than 50 years old. When it is present in patients younger than 40 years, it is strongly associated with diabetes.
authors.affiliation: Department of Radiology, School of Medicine, University of New Mexico, Albuquerque 87131-5336.
authors.forename: B L
authors.initials: BL
authors.lastname: Hart
authors.forename: J A
authors.initials: JA
authors.lastname: Spar
authors.forename: W W
authors.initials: WW
authors.lastname: Orrison
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D002114:Calcinosis / Q000150:complications* / Q000000981:diagnostic imaging*; D002357:Cartilage Diseases / Q000150:complications* / Q000000981:diagnostic imaging; D002648:Child; D002675:Child, Preschool; D048909:Diabetes Complications; D003920:Diabetes Mellitus / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009916:Orbital Diseases / Q000150:complications* / Q000000981:diagnostic imaging; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed