Ultrasound quantitative evaluation of human eye cataract

Abstract

Šiame darbe pagrįsta metodika skirta kataraktos subrendimo stadijos nustatymui, pateikiami šios metodikos tyrimo rezultatai. Kauno medicinos universiteto Biomedicininių tyrimų instituto Oftalmologijos laboratorijoje buvo atliekamas ultragarsinis paxcientų tyrimas, diagnostiniai signalai nuo akies lęšiuko buvo diskretizuojami, išsaugojami ir vėliau analizuojamni panaudojant skaitmeninių signalų apdorojimo metodus. Kataraktos kokybiniam įvertinimui pasiulytas naujas diagnostinis parametras- lęšiuko kokybės koeficientas QL. Šis koefocientas apibūdina du ultragarso sąveikos su akies lęšiuku audinio aspektus - signalo slopinimą ir išsibarstymą [...]. A technique to improve an eye cataract early detection and quantitative evaluation of maturity using ultrasound was investigated. A broadband coherent signal, backscattered from an eye lens tissue, was digitized, recorded and processed. A new parameter - lens quality was proposed for the human eye cataract quantitative evaluation. Lens quality reflects two phenomena of ultrasound interaction with lens tissue - attenuation and scattering. Digital technique for echo-signal energy and time frequency analysis was applied, ultrasound waves scattering strength and spectral slope was calculated. Experimental statistical investigations performed with signals divided into five groups - mature cataract, immature form of cataract, incipience cataract phase, healthy lenses and human eye phantom. Investigations have showed that value of specific quality in the test groups vary in the wide range from 1 to 60. This feature allows theoretically differentiate eye lenses cataract in different classes with defined boundaries. Presented results show that we with high reliability can differentiate lenses into three groups: healthy lenses (Q_{L} > 50), lenses with incipient or immature cataract (Q_{L} = 2-20) and lenses with mature cataract (Q_{L} < 1). The investigated method can be used for an eye lens classification and for early cataract detection This technique was used at the Department of Ophthalmology, Institute for Biomedical Research, Kaunas University of Medicine.