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.
- Proton NMR imaging
- pulse sequence