ADCIS - Software products and custom development in the fields of image processing and analysis

Automated lesion detection in retinal images

Retinal Analysis Tool, an Aphelion™ stand-alone application, is an advanced and powerful tool for studying the fundus of the eye, using retinographic images. The Tool's processing of fundus images is fully automatic. Its underlying methodology was originally developed in partnership with two prestigious institutes: the Center for Mathematical Morphology at the School of Mines in Paris, and the Lariboisière Hospital in Paris, France1.

Current use of the Retinal Analysis Tool is for disease research only. However, this software is also available for integration into system applications for clinical uses, subject to approval by applicable regulatory agencies. Such applications could include diabetic retinopathy and age-related macular degeneration (ARMD).

The following tasks are performed on a color, angiographic image without human interaction: Filtering to enhance the image Locating the papilla (the optical nerve) Analyzing the blood vessel network Detecting the branching points Detecting micro-aneurysms Detecting exudates and hemorrhages Locating the macula as the central dark area

Detection of retinal lesions

Graphical User Interface

In addition to its graphical user interface and image processing tools, a set of measurements is provided to quantify images: Micro-aneurysm count Number of vessel network branch points Mean blood vessel diameter Papilla size to evaluate glaucoma progression Image and papilla densitometry data

1 The original development work was funded by the French Ministry of Research.

Purpose of the application

To describe a slit lamp-based imaging system and software that objectively and automatically quantifies conjunctival hyperemia. Conjunctival hyperemia is an important indicator of several ocular conditions including ocular surface inflammation, ocular irritation, and systemic disease. It is associated with increased blood volume in the anterior scleral, bulbar conjunctival and limbal vessels. Since conjunctival hyperemia is a consistent clinical sign of the ocular response to physiological and pathological stimuli, it has been considered an important endpoint in efficacy and safety trials for contact lenses, medications, as well as for evaluation of ocular toxicity of drugs, chemicals and pollutants. Thus, assessing the progression of conjunctival hyperemia is critically important for the treatment of patients with ocular disease.

Methods

The Imaging System for the Ocular Surface (ISOS) consisting of hardware and software components was developed to capture images and perform automated image analysis of conjunctival blood vessel morphology. It is a joint development between Novartis and ADCIS. A pilot study was conducted to obtain and analyze conjunctival images from patients with allergic conjunctivitis following allergen challenge. Manual image grading was performed on sets of images that were subsequently processed by image analysis. A statistical correlation of grading and image analysis results was performed, and a machine learning-based automatic hyperemia grading system was integrated in ISOS.

Results

Automatic image analysis using ISOS resulted in the ability to evaluate changes in a variety of morphological parameters of vessels that were not quantifiable to clinical observers (e.g. vessel dimensions such as diameter, total length, density), and correlate them with human grading. A machine learning-based system was developed in ISOS to mimic human grading and automatically quantify hyperemia from 35 morphological parameters. The automatic grading provided by ISOS was robust, highly correlated to manual image grading, and provided an objective hyperemia grade within a few seconds.

Manual grades between 0 (no redness and 4)

Conclusion

This pilot study demonstrated that the ISOS suite represents a valuable tool for objective assessment of conjunctival hyperemia. ISOS minimized grading variations across images and provided clinically meaningful measurement of conjunctival hyperemia and insights into the progression of ocular hyperemia. ISOS was fast, reliable, accurate, and most importantly, eliminated human bias in assessing conjunctival hyperemia.

ARIES (AlConfocal Rapid Image Evaluation System) is a software product developed by ADCIS for Alcon Laboratories to automatically process images of the cornea acquired by a confocal microscope.

Confocal microscopy allows for high resolution, reliable, real time, imaging of the living corneal microstructure including normal corneal morphology, pathogen invasion, dystrophies and degenerations, post surgical management, dry eyes, drug toxicities, endothelial monitoring and contact lens related changes.

Two modes are available in the software: Automatic and Manual. In Manual mode, the user can interactively draw annotations in the image overlay to mark each cell and save those annotations on disk in a file at the Aphelion™ format (.aso). In automatic mode, the automatic segmentation of the nerve layer, the Wing Cell and the Immune Cell can be performed, measurements on the resulting objects can be computed, and histogram of one selected measurement can be displayed in the graphical user interface (GUI). In Post-Processing Editing Mode, the user can interactively annotate objects resulting from the automatic segmentation.

An article describing the application is published in the journal Cornea magazine.

ReV Analyzer (Retinal Volume Analyzer) is a software product that takes as input OCT images of a patient, detects and analyzes the retinal Pigment Epithelium Detachment (PED) in that series of images, generates a 3D volume in the 3D space, and provides information on the PED evolution over different visits. It also works on other retina-choroidal areas in a semi-automatic way.

ReVAnalyzer can be used for patients with vascularized PEDs in the scope of exudative Age Related Macula Degeneration, when the PED is visible in multi modal images. Typically, an ophthalmologic clinical examination is performed on a patient during multiple visits, and images of fluorescein and ICG angiography are captured, along with an SD OCT examination in Enhanced Depth Imaging (EDI) mode. ReVAnalyzer is fully compatible with the Spectralis HRA+OCT system manufactured by Heidelberg Engineering GmbH, Heidelberg, Germany.