Microfocus computed tomography as a new method for high-resolution imaging of microstructures in the eye: a pilot study

Abstract

 

Purpose

 

Histopathological examination requires processing and provides a two-dimensional (2D) view on the sections of a specimen. The aim of this study is to investigate the structural characteristics of the eye in an ex-vivo study using high-resolution microfocus computed tomography (micro ct) without the need of processing and providing three-dimensional (3D) non-destructive sectional images.

 

Methods

 

The study was approved by the institutional reviewboard, and informed consent was obtained. A total of 4 specimens were used. Among them were 3 enucleated human bulbi and 1 exenterated swine eye. The 3 human specimens had underwent regular histopathological examination. Diagnoses of the human specimens were angle closure glaucoma, retinal detachment and malignant melanoma. The swine eye had been used for surgical training and a CyPass micro-stent® had been implanted. All specimens were fixated in paraffin. We obtained images with a high-resolution micro ct system (v|tome|x by GE®) for 3D computed tomography and 2D non-destructive X-ray inspection. The maximum resolution is 2-20 micrometers depending on the sample size.

 

Results

 

The obtained images showed good correlation with histopathologic findings. The maximum resolution in our specimens is 20 micrometers. In the 2D-images retinal, choroidal, uveal, corneal and lental tissues can be distinguished among others. The configuration of the anatomical structures e.g. the chamber-angle can be assessed without damaging the integrity of the specimen. The exact position of a surgically applicated device like the CyPass micro-stent® can be assessed faster and more accurate than with standard histological examination. The 3D-images give a helpful overview of the anatomical structures but cannot distinguish between tissues as good as the 2D-images.

 

Conclusions

 

The results of this study indicate that ex-vivo micro ct is a helpful research tool in the examination of enucleated bulbi with excellent correlation to histo-pathologic findings. Although at present not applicable in vivo because of the radiation load and sample size, micro ct is a valuable complimentary tool in ex-vivo diagnostics and in the development of new surgical techniques and ophthalmic devices.  

 

3D rendering of a swine eye with a micro-stent

 

 

orthogonal 2D slice of a a swine eye with a micro-stent