ABSTRACT
Several osmotic cataract models as well as human diabetic lenses were tested by nuclear magnetic resonance spectroscopy and imaging. Both longitudinal (T1) and transverse (T2) relaxation times increased with increase in lens hydration. Therefore proton magnetic resonance imaging (MRI) can be used to detect changes of the biophysical environment of water proton in the lens. T2-weighted imaging sequence (spin-echo) can be used to differentiate lenses with hydrational changes since they exhibit higher signal intensity (because of long T2) than normal lenses at the same TE (echo time). A greater contrast can be achieved with the inversion-recovery sequence, which, in addition to contribution from T2, also incorporates T1 and proton density terms. Proton MRI is potentially useful for the detection of pre-cataractous changes.
Subject(s)
Lens, Crystalline/pathology , Aged , Aged, 80 and over , Animals , Cataract/pathology , Diabetes Mellitus/pathology , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged , Rabbits , WaterSubject(s)
Antigens/analysis , Retina/immunology , Animals , Antigens/immunology , Arrestin , Cattle , Guinea PigsABSTRACT
The course of development of cataract in diabetic rats induced by streptozotocin was followed with photoslit lamp during a 14-week period, and the process of cataract was divided into six stages. Until stage III, two types of lens opacification were distinguished. In lenses called type A, vacuoles spread from the equator of the superficial cortex, while in lenses called type B, a diffuse cloudiness progresses in the deep cortex with little vacuolization. At stage IV, the vacuoles disappeared and type A opacities resemble those of type B. At stage V, opalescent changes became visible near the central part of lens after 6 weeks. At stage VI, the whole lens had become cloudy.
