Yong Gao MS, Presenter: Nothing to Disclose

Judy Rose James MS, Abstract Co-Author: Nothing to Disclose

Navin Bansal PhD, Abstract Co-Author: Nothing to Disclose

The main goal of this research is to develop single-quantum (SQ) and triple-quantum-filtered (TQF) 23Na MRI to detect cellular damage in hepatitis and cirrhosis. Effects of liver damage by hepatotoxicant, CCl4, on the rat liver were examined by SQ and MQF 23Na MRI. The results of 23Na MRI experiments were validated by quantification of relative intra- and extracellular spaces (rICS and rECS, respectively), and total and intracellular Na+ concentrations ([Na+t] and [Na+i ], respectively) with shift-reagent (SR) aided 23Na and 31P MRS.

Liver damage was induced in male Wistar rats by oral administration of 2.5 ml/kg CCl4 plus 2.5 ml/kg corn oil. Control animals received 5.0 ml/kg corn oil. SQ and TQF 23Na MRI experiments were performed on a 9.4-T 31-cm MR system (Varian Inc.) before and 24 hr after CCl4 treatment. After the 24 hr MRI experiment, the liver was exposed and a 2 cm surface coil tunable to 23Na and 31P frequencies was placed on the liver for SR experiments. rICS, rECS, [Na+t] and [Na+i] were calculated from TmDOTP5- signal in 31P spectra and Na+i and Na+e signals in 23Na spectra. Changes in cellular bioenergetics (ATP/Pi), intracellular pH (pHi) and free [Mg++] were calculated from 31P spectra.

SQ 23Na MRI showed an 83% increase in [Na+t] and TQF 23Na MRI showed a 170% increase in [Na+i] 24 hrs after CCl4 treatment. SR-aided 23Na and 31P experiments showed no change in rICS (p < 0.216) and rECS (p < 0.216) but both [Na+]t (32 ± 3 to 46 ± 4 mmoles/kg wet-weight, p < 0.005) and [Na+i] (17 ± 2 to 49 ± 7 mmoles/kg cellular water, p<0.005) increased dramatically. 31P spectra from the tissue metabolites showed a significant decrease in the ATP/Pi ratio (1.24 ± 0.08 to 0.94 ± 0.10; p < 0.012) but no change in pHi (p < 0.64) and free [Mg++] (p < 0.53).

Among all the parameters measured, [Na+i] (as determined by both TQF 23Na MRI and SR-aided 23Na MRS) showed the largest change after liver damage by CCl4. These data suggest that TQF 23Na MRI is a sensitive technique to monitor cellular dysfunction in hepatitis and cirrhosis.  

Assessing the severity of liver damage at cellular level by SQ and TQF 23Na MRI may prove useful for the diagnosis and staging of liver diseases.

Gao, Y, James, J, Bansal, N, Monitoring Hepatic Cellular Damage by Single-Quantum and Triple-Quantum-filtered Sodium MRI.  Radiological Society of North America 2008 Scientific Assembly and Annual Meeting, February 18 - February 20, 2008 ,Chicago IL. http://archive.rsna.org/2008/6022256.html