Radiotracer imaging studies in hepatic encephalopathy: ISHEN practice guidelines

Area of Science:

• Neuroscience
• Radiology
• Gastroenterology

Background:

• Consensus is lacking regarding radiotracer use in hepatic encephalopathy (HE).
• Current research focuses on radiotracer imaging in HE animal models, methodological challenges, and its application in understanding HE pathophysiology and therapies.

Purpose of the Study:

• To review radiotracer imaging in HE, covering animal models, methodology, and clinical applications.
• To propose standardized protocols for multicenter human studies and identify alternative imaging techniques for clinical practice.

Main Methods:

• Review of radiotracer imaging techniques including Positron Emission Tomography (PET), Single Photon Emission Computed Tomography (SPECT), and Magnetic Resonance Imaging (MRI).
• Analysis of studies on HE animal models and human subjects, focusing on pathophysiology and therapeutic interventions.
• Evaluation of methodological issues and potential for multicenter collaborations.

Main Results:

• PET and SPECT are suitable for HE animal models, with model selection depending on the research question; MRI is a viable alternative.
• Multicenter human PET studies with unified protocols are needed to overcome limitations of small, underpowered studies.
• While radiotracer imaging aids research, Magnetic Resonance Spectroscopy (MRS) and volumetric MRI are more practical for routine clinical diagnosis and prognosis due to fewer technical challenges.

Conclusions:

• Radiotracer imaging remains a valuable research tool for HE pathogenesis and treatment assessment.
• Standardized multicenter PET studies are recommended for human HE research.
• MRS and volumetric MRI are currently the most promising objective tools for clinical HE assessment, offering advantages over radiotracer imaging in routine practice.