Magnetic resonance T 2 ‐relaxometry and 2D L‐correlated spectroscopy in patients with minimal hepatic encephalopathy

Purpose: To evaluate T 2 ‐relaxation changes in patients with minimal hepatic encephalopathy (MHE) using T 2 relaxometry and to correlate T 2 values with brain metabolites evaluated using 2D magnetic resonance spectroscopy (MRS). Materials and Methods: Eight MHE patients and 13 healthy subjects were evaluated using T 2 relaxometry, and eight patients and nine healthy subjects underwent 2D MRS in right frontal and left occipital regions. Whole‐brain T 2 ‐relaxation maps were compared between MHE and control subjects using analysis‐of‐covariance, with age and gender included as covariates. T 2 values derived from the right frontal and left occipital lobes were correlated with the metabolite ratios. Results: Multiple brain regions including anterior and mid cingulate cortices, right anterior and left posterior insular cortices, right prefrontal, medial frontal, and right superior temporal cortices showed significantly increased T 2 values in MHE patients compared to control subjects. MRS showed significantly increased ratios of glutamine/glutamate (Glx) and decreased ratios of myo‐inositol, taurine, choline, and myo‐inositol/choline (mICh) with respect to creatine (Cr_d) in patients compared to controls. Frontal Glx/Cr_d showed significantly positive correlation with T 2 values. Conclusion: MHE patients showed significantly increased T 2 values in multiple brain regions reflecting increased free water content and T 2 values in frontal lobe correlated with the increased Glx/Cr_d ratio. J. Magn. Reson. Imaging 2009;30:1034–1041. © 2009 Wiley‐Liss, Inc.