Quantitative Magnetization EXchange MRI Measurement of Liver Fibrosis Model in Rodents.

Background: Quantitative MRI can elucidate the complex microstructural changes in liver disease. The Magnetization EXchange (MEX) method estimates macromolecular fraction, such as collagen, and can potentially aid in this task.

Hypothesis: MEX sequence, and its derived quantitative macromolecular fraction, should correlate with collagen deposition in rodents liver fibrosis model.

An in vivo implementation of the MEX MRI for myelin fraction of mice brain.

Objective: Magnetization EXchange (MEX) sequence measures a signal linearly dependent on the myelin proton fraction by selective suppression of water magnetization and a recovery period. Varying the recovery period enables extraction of the percentile fraction of myelin bound protons. We aim to demonstrate the MEX sequence sensitivity to the fraction of protons associated with myelin in mice brain, in vivo.

Deuterium double quantum-filtered NMR studies of peripheral and optic nerves.

Objective: Characterization of the nerve components by deuterium double quantum-filtered magnetization transfer (DQF-MT) NMR.

Methods: Nerves were equilibrated in deuterated saline and H single-pulse and H DQF-MT NMR spectra were measured, enabling the separation of the different water compartments, according to their quadrupolar splittings.

Results: Rat sciatic and brachial nerves and porcine optic nerve immersed in deuterated saline yielded H DQF spectra composed of three pairs of quadrupolar-split signals assigned to the water in the collagenous compartments and the myelin bilayer and one narrow signal assigned to the axonal water.

Identification of water compartments in spinal cords by H double quantum filtered NMR.

In H double quantum filtered (DQF) NMR, the various water compartments are characterized by their different residual quadrupolar interactions. The spectral separation between the different signals enables the measurement of the relaxation of each compartment and the magnetization transfer (MT) between them. In the current study, five water compartments were identified in the H DQF spectra of porcine spinal cord.

New insight into the organization of myelin water using deuterium NMR.

Purpose: Myelin water is commonly characterized by its short proton T relaxation time, suggesting strong association with the polar head groups of the bilayer constituents. Deuterium NMR of water in ordered structures exhibits splittings as a result of quadrupolar interactions that are observable using the double-quantum filter. The purpose of the current study was to identify and characterize the water populations.