Incidence of calcification of the trochlear apparatus in the orbit

Purpose: To quantify the incidence of asymptomatic incidental trochlear calcifications and to describe their clinical features.

Methods: We retrospectively reviewed orbital computed tomography (CT) scans of 216 patients to identify the presence of trochlear calcifications. We analyzed the prevalence, age distribution, and gender preponderance of trochlear calcifications. We also examined age-specific prevalence rates for trochlear calcifications, as well as their relationship to systemic disease.

Results: The mean age of patients was 26.8 years. Trochlear calcifications were observed in 35 (16%) of the 216 patients, and 18 of the 35 patients had bilateral calcifications. The rate of trochlear calcification was higher in males; 32 (20.9%) of 153 male patients had trochlear calcifications, compared with 3 (4.8%) of 63 female patients. Age, hypertension, diabetes mellitus, and thyroid disease were not significantly associated with the incidence of trochlear calcifications.

Conclusions: Incidental asymptomatic orbital calcification is more commonly observed on CT images than we expected and occurs predominantly in male patients. Understanding this to be a relatively common, benign finding may help us to rule out foreign bodies and other pathologic conditions.