Diffusion-weighted imaging in acute hyperammonemic encephalopathy

Area of Science:

• Neurology
• Radiology
• Hepatology

Background:

• Chronic liver disease (CLD) is associated with specific MRI findings like cerebral atrophy and globus pallidus hyperintensities.
• Acute hepatic encephalopathy (AHE) presents with distinct MRI changes that can be confused with hypoxic-ischemic injury.
• Limited description of AHE's neuroimaging in the literature poses diagnostic challenges.

Purpose of the Study:

• To describe the characteristic MRI findings in acute hyperammonemic encephalopathy.
• To differentiate AHE imaging patterns from those of CLD and hypoxic-ischemic injury.
• To enhance the understanding of AHE's neuroimaging in clinical practice.

Main Methods:

• Case series of three patients with acute hyperammonemic encephalopathy.
• Detailed analysis of magnetic resonance imaging (MRI) findings, including T1-weighted, T2-weighted, and diffusion-weighted images.
• Correlation of imaging findings with clinical presentation and laboratory results.

Main Results:

• Acute hyperammonemic encephalopathy demonstrated restricted diffusion in the insular and cingulate cortices and bilateral thalami.
• These diffusion changes were not consistently observed on T2-weighted images.
• Findings were distinct from typical chronic liver disease-related MRI changes.

Conclusions:

• Acute hyperammonemic encephalopathy has a characteristic MRI pattern of restricted diffusion in specific brain areas.
• Recognizing these distinct MRI findings is crucial to avoid misdiagnosis as hypoxic-ischemic injury.
• Further research is warranted to fully elucidate the neuroimaging spectrum of AHE.