Magnetic Resonance Spectroscopy for Evaluating Portal-Systemic Encephalopathy in Patients with Chronic Hepatic Schistosomiasis Japonicum

<div><p>Portal-systemic encephalopathy (PSE) is classified as type B hepatic encephalopathy. Portal-systemic shunting rather than liver dysfunction is the main cause of PSE in chronic hepatic schistosomiasis japonicum (HSJ) patients. Owing to lack of detectable evidence of intrinsic liver disease, chronic HSJ patients with PSE are frequently clinically undetected or misdiagnosed, especially chronic HSJ patients with covert PSE (subclinical encephalopathy). In this study, we investigated whether magnetic resonance spectroscopy (MRS) could be a useful tool for diagnosing PSE in chronic HSJ patients. Magnetic resonance (MR) T1-weighted imaging, diffusion-weighted imaging, and MRS were performed in 41 chronic HSJ patients with suspected PSE and in 21 age-matched controls. The T1 signal intensity index (T1SI) and apparent diffusion coefficient (ADC) value were obtained in the Globus pallidus. Liver function was also investigated via serum ammonia and liver function tests. Higher T1SI and ADC values, increased lactate and glutamine levels, and decreased myo-inositol were found in the bilateral Globus pallidus in chronic HSJ patients with PSE. No significantly abnormal serum ammonia or liver function tests were observed in chronic HSJ patients with PSE. On the basis of these findings, we propose a diagnostic procedure for PSE in chronic HSJ patients. This study reveals that MRS can be useful for diagnosing PSE in chronic HSJ patients.</p></div

The diagnostic flow chart for chronic HSJ patient with suspected PSE.

<p>A fasted blood manganese should be tested in chronic HSJ patient with suspected PSE. If hypermanganesemia (blood manganese ≥ 54.85 μg/L) is found, liver function tests and abdominal CT or ultrasonic scan should be performed to establish whether liver dysfunction or portal-systemic shunting (or both) exist. Finally, a brain MRI and MRS can be performed to detect whether T1-hyperintensity, increased Lac, Glx, and decrease mI can be observed in bilateral Globus pallidus. Chronic HSJ patient with increased Lac and Glx but decreased mI should be considered as PSE. Chronic HSJ patients with abnormal neurological appearance should be considered as having overt PSE. Chronic HSJ patients with normal neurological parameters but abnormal neuropsychological performance should be considered as having covert PSE. Other patients should be followed up.</p

Laboratory, magnetic resonance imaging, and spectroscopy findings in different groups

<p>Laboratory, magnetic resonance imaging, and spectroscopy findings in different groups</p

T1WI/MRS in the healthy volunteer and in chronic HSJ patients with and without PSE.

<p>No abnormal findings on T1WI and MRS were seen in a healthy volunteer (A) and a chronic hepatic schistosomiasis japonicum (HSJ) patient without portal-systemic encephalopathy (PSE) (B). Hyper intensity on T1WI, increased lactate (Lac/Cr) and glutamate/glutamine (Glx/Cr) levels, and decreased myo-inositol (mI/Cr) levels on MRS were found in the chronic HSJ patent with covert PSE (C). Obvious hyper intensity on T1WI, obviously increased lactate (Lac/Cr) and glutamate/glutamine (Glx/Cr) levels, and decreased myo-inositol (mI/Cr) levels on MRS were found in the chronic HSJ patient with overt PSE (D). The region of interest (ROI) was located in Globus pallidus on MRS.</p