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Type:
Educational Exhibit
Keywords:
Metabolic disorders, Cirrhosis, Diagnostic procedure, MR-Spectroscopy, MR-Diffusion/Perfusion, MR, Neuroradiology brain
Authors:
L. Farras Roca1, J. J. Sánchez Fernández2, P. Puyalto3, P. Mora Montoya2, M. Cos Domingo2, C. M. Grassi Zamora2, D. S. Palominos Pose2, J. C. Sardiñas Barrero2, C. Majós Torró2; 1Barcelona/ES, 2L\' Hospitalet de Llobregat-Barcelona/ES, 3Badalona/ES
DOI:
10.1594/ecr2016/C-1352
Findings and procedure details
MRI can show a specific pattern of cerebral metabolic changes and measure abnormal deposits of different substances that under normal circumstances are metabolized by the liver.
T1-weighted images show hyperintense signal in the globus pallidus,
subthalamic region and midbrain (Fig.
1,2,3). The increased T1 signal is due to a rise in manganese concentration (a paramagnetic substance),
with preferential deposition in the globus pallidus and substantia nigra.
This finding has also been seen in patients receiving total parenteral nutrition,
those with occupational exposure to manganese from welding,
and those with noncirrhotic portal vein thrombosis or congenital portal-systemic bypass and no intrinsic hepatocelular disease.
The signal intensity may reverse after normalization of liver function or discontinuation of manganese intake.
Cortical edema and hyperintensity on T2-weighted and FLAIR images are also present affecting the insular cortex and cingulated gyrus,
with sparing the perirolandic and occipital regions (Fig.
4,5).
Notably,
the extent of severity on FLAIR and DWI correlates with the plasmatic ammonia level.
Another typical finding seen on acute hepatic encephalopathy is a hyperintensity on T1 weighted images in a small pituitary gland (Fig.6).
MR spectroscopy can detect intracellular metabolic shifts in HE as usually shows an increased concentration of glutamine/glutamate coupled with decreased myo-inositol and choline signals and normal N-acetylaspartate (Fig.7). The choline peak normalizes earlier than the other peaks and at one-two months may even show a small increment over normal values,
and the myoinositol peak normalize slower.
The main differential diagnosis list given the hyperintensity seen in basal ganglia on T1 weighted images are situations with liver cooper overload such as Wilson disease or cholestatic disease,
situations with hyperalimentation,
or hypoxic-ischemic encephalopathy (Fig.8), Fahr disease or neurofibromatosis type 1.