mercoledì 8 ottobre 2008

Amyloid angiopathy with subacute right temporal lobe hemorrhage


Heterogeneous right temporal lobe mass with a thin rim of peripheral enhancement and moderate surrounding parenchymal edema. There is associated susceptibility on gradient images, however no diffusion restriction. There is effacement of the posterior horn and trigone of the right lateral ventricle, as well as adjacent sulcal effacement. There are also multiple punctate/small foci of susceptibility distributed throughout the cerebral and cerebellar hemispheres centered at the corticomedullary junction. Also noted (but not shown) were foci of T2 prolongation scattered throughout the centrum semiovale, corona radiata, and subcortical white matter, consistent with microvascular disease.

Differential diagnosis:
- Hypertensive micro hemorrhages
- Ischemic stroke with micro hemorrhage
- Multiple vascular malformations
- Traumatic diffuse axonal injury
- Amyloid angiopathy
- Hemorrhagic metastasis
- CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy)
- Metallic microemboli from artificial heart valves

Diagnosis: Amyloid angiopathy with subacute right temporal lobe hemorrhage

Key Points

Amyloidosis – rare systemic disease caused by extracellular deposition of ß-amyloid
10-20% localized form, inclusive of CNS
Can be idiopathic/primary or secondary/reactive (dialysis related amyloidosis)

Cerebral amyloid deposition: 3 varieties
- Cerebral amyloid angiopathy (most common)
- Amyloidoma (rare)
- Diffuse white matter involvement (rare)

Common cause of spontaneous lobar hemorrhage in elderly (1% of all strokes)
Responsible for 15-20% of ICH in patients >60 years old
27-32% of normal elderly (autopsy)
82-88% in Alzheimer's disease
Common in Down's syndrome

Imaging features

Multifocal "black dots" representing chronic micro hemorrhages.
Lobar hemorrhages of different ages.
Involves subcortical WM (gray/white junction), parietal and occipital lobes (autopsy), also frontal and temporal lobes.
Less commonly involves brainstem, deep gray matter, cerebellum, hippocampus.
Acute lobar hemorrhages tend to be large and irregular with dependent blood sedimentation.
Punctate foci of dark susceptibility on T2*GRE sequences (blooming) seen with chronic micro hemorrhages.
Focal or patchy/confluent WM disease associated in approximately 70%.

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