Racial and Gender Differences in the Natural Lens Detected on Dual-Energy (DE) CT

Abstract

Purpose : It is not known whether Dual Energy-Computed Tomography (DE-CT) might be able to detect differences in the crystalline lens that could be related to physiologic differences in lens opacity or incidental cataract formation. This study investigated whether there is a relationship between possible demographic and clinical risk factors for cataract and x-ray attenuation of the crystalline lens on DE-CT of the head.

Methods : Retrospective review of 198 eyes in 103 adult subjects who underwent DE-CT exams of the head. Regions of interest spanning 3-5 mm² were placed over the center of the native crystalline lens and the x-ray attenuation of each lens was recorded in Hounsfield Units (HU) at 3 DE-CT energy levels: 40 keV, 70 keV, and 190 keV. Demographic and environmental risk factors for cataract were collected from the medical record. Generalized estimating equations were used to assess the relationship between these risk factors and relative density of the lens at each energy level.

Results : The mean age in the older vs. younger cohort was 81.4 5.7 yrs vs. 22.66 2.93 yrs. 46.6% of subjects were female, 38.8% non-Hispanic white, 22.3% diabetic, and 37.9% never smokers. The mean HU attenuation values were significantly lower for the older vs. younger group (GEE p=0.022) at 40 keV, but there was no significant difference at higher energy levels (70 or 190 keV; all p>0.05). Mean HU attenuation values were significantly higher for females vs. males (40 keV: 76.4±13.3 vs. 70.7±1.3; 70 keV: 79.0±7.4 vs. 74.2±7.6; 190 keV: 80±7.9 vs. 75.8±9; all p<=0.01) and non-whites vs. non-Hispanic whites (40 keV: 77.6±13.1 vs. 70.5±13.2; 70 keV: 80±7.9 vs. 74.1±7.0; 190 keV: 81.0±8.1 vs. 75.5±8.5; all p<=0.001) at all 3 energy levels. However, there was no significant association between lens attenuation and either diabetes or smoking status (all p>0.05). In multivariable analysis, both female sex (all p<0.01) and nonwhite race (all p<0.01) but not age-group (p>0.05) remained significant independent predictors of lens attenuation at all 3 energy levels.

Conclusions : The crystalline lens of females and non-white subjects had significantly higher attenuation on DE-CT, which may suggest higher density or increased concentration of materials like calcium. These groups may be at greater risk for cataracts independent of other well-known risk factors such as age, diabetes, or smoking status.

This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.