Adding another spectral dimension to ¹H magnetic resonance spectroscopy of hepatic encephalopathy

Purpose: To evaluate a localized two-dimensional correlated magnetic resonance spectroscopic (L-COSY) technique in patients with hepatic encephalopathy (HE) and healthy subjects, and to correlate the cerebral metabolite changes with neuropsychological (NP) test scores. Materials and Methods: Eighteen minimal hepatic encephalopathy (MHE) patients and 21 healthy controls have been investigated. A GE 1.5-T magnetic resonance (MR) scanner was used in combination with a body MR coil for transmission and a 3-inch surface coil for reception. A 27-mL voxel was localized by three slice-selective radio frequency (RF) pulses (90°-180°-90°) in the anterior cingulate region. The total duration of each two-dimensional L-COSY spectrum was approximately 25 minutes. The NP battery included a total of 15 tests, which were grouped into six domains. Results: MR spectroscopic results showed a statistically significant decrease in myo-inositol (ml) and choline (Ch) and an increase in glutamate/glutamine (Glx) in patients when compared to healthy controls. There was also an increase in taurine (Tau) in patients. The NP results indicated a significant correlation between motor function assessed by NP tests and ml ratios recorded using two-dimensional L-COSY. Conclusion: The study demonstrated the feasibility of evaluating the two-dimensional L-COSY sequence in a clinical environment. The results showed additional cerebral metabolites that can be measured with the technique in comparison to one-dimensional study.