Hypertrophic olivary degeneration-MRI
Case Report: 50 year old hypertensive with
prior history of stroke, presents with loss of fine voluntary movements. MRI
shows an ill defined, T2 low signal intensity foci in the lower pons suggesting
hemosiderin and ferritin deposits with relatively well defined T2 hyperintensity
and enlargement of the left anterior medulla in the inferior olivary nucleus
region with no restricted diffusion, suggesting possible hypertrophic olivary
degeneration (HOD) secondary to pontine haemorrhage.
Case submitted by Dr MGK Murthy, Mr Sentil & Mr Venkat
Teaching points :
- Is a form of trans-synaptic
degeneration. End result of the damage
of the neuronal connections between dentate nucleus , red nucleus &
inferior olivary nucleus (dentate-rubral-olivary pathway).
- Unique type
of degeneration in view of enlargement of the effected inferior olivary
neurons. Dentate nucleus is connected
to contralateral red nucleus via ipsilateral inferior olivary nucleus and
controls fine voluntary movement (called Gullain and Mollaret triangle).
- Red nucleus
of one side is connected to the ipsilateral inferior olivary nucleus via
different tract called central
segmental tract. HOD can occur due to any focal lesion including ischaemia, demyelination
& neoplasms.
- Typically
seen within 4 to 6 months of the primary brain stem insult. Olivary hypertrophy
usually resolves in 10 to 16 months, though T2 hyperintensity may persist for
years,...
Source: Sumer's Radiology Site - Category: Radiologists Authors: Sumer Sethi Source Type: blogs
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