The "eye of the tiger" sign is a radiological finding seen on T2-weighted MRI images, characterized by abnormal low signal intensity in the globus pallidus, with a central longitudinal zone of high signal.
Here's a breakdown:
- Globus Pallidus: This is a structure in the brain involved in motor control.
- T2-weighted MRI: A specific type of MRI sequence sensitive to water content in tissues.
- Low Signal Intensity: On a T2-weighted MRI, areas with low signal intensity appear dark. In the context of the "eye of the tiger" sign, this darkness indicates abnormalities in the globus pallidus.
- High Signal Intensity: On a T2-weighted MRI, areas with high signal intensity appear bright. The central longitudinal zone of brightness within the darkened globus pallidus creates the appearance of an "eye."
The "eye of the tiger" sign is most commonly associated with:
- Pantothenate Kinase-Associated Neurodegeneration (PKAN): This is a rare, inherited neurological disorder that causes progressive movement difficulties, speech problems, and dementia. The "eye of the tiger" sign is a characteristic feature of PKAN but may not be present in all cases.
Although primarily linked to PKAN, it is important to note that similar MRI findings, although less typical, can sometimes be observed in other rare neurological conditions.
In summary, the "eye of the tiger" lesion refers to a distinctive appearance on MRI scans that suggests a specific underlying neurological condition, most notably PKAN.
