Which imaging finding is characteristic of Huntington disease?

• A. Increased glucose metabolism in the caudate and putamen on PET.
• B. Hemorrhage in the caudate nucleus on CT.
• C. Cerebral and caudate nucleus atrophy on CT.
• D. Normal MRI findings.

Answer: (C)

Huntington disease causes degeneration of the striatum, especially the caudate nucleus, leading to brain tissue loss that is visible on CT or MRI as atrophy. As the caudate shrinks, the frontal horns of the lateral ventricles enlarge due to ex vacuo ventriculomegaly, and broader cerebral atrophy can be seen with progression. This imaging pattern—caudate (and often broader) atrophy on CT—is characteristic of Huntington disease. In contrast, PET would show reduced, not increased, metabolism in the caudate and putamen; hemorrhage in the caudate is not typical, and a normal MRI would not fit the neurodegenerative changes of this condition.