Frontal sinus index for sex estimation: Is it possible?

Abstract Objectives This study aimed to evaluate the sex predictive value of the frontal sinus index (FSI) assessed on lateral cephalometric and cone beam computed tomography (CBCT) images in a sample of Egyptian population. Materials and Methods 100 digital lateral cephalometric and 100 CBCT images, each consisting of 50 males and 50 females, of known age and sex were retrospectively collected. The patients' images were subdivided into two equal groups according to their age: below 18 years and at or above 18 years. The maximum anteroposterior frontal sinus width (FSW) and height (FSH) were measured by two radiologists on both images then the FSI was calculated. The patients' data including sex, age, FSW, FSH and FSI were tabulated and statistically analyzed. Results Upon comparing both sexes, cephalometric FSI was found to be statistically significantly different at the below 18 years age group and when using receiver operating characteristic (ROC) analysis, the index could only act as a poor sex predictor (area under curve: 0.66). For the logistic regression analysis, cephalometric FSW was found to be the only sex predictor at or above 18 years age group in the last step of the stepwise logistic regression. According to this equation, 68% of males and 64% of females were correctly predicted with an overall accuracy of 66%. Conclusion Despite that sexual dimorphism could exist, frontal sinus index (FSI), whether assessed on CBCT or cephalometric radiographic images, has poor value as a sex predictor in the studied age groups.