owl-eyes sign (spinal cord)
Location,
length, and enhancement: systematic approach to differentiating intramedullary spinal cord lesions. Hirayama disease. A 22-year-old male with upper extremity weakness and muscle atrophy. a There is focal T2 hyperintensity in the anterior horns (arrowheads). Subtle asymmetric focal cord atrophy at this level (C5–C6), slightly more conspicuous on the left (arrow). b Flexion view shows anterior displacement of the dura (arrows) with narrowing of the thecal sac (bracket), extending from C3 to T2, most pronounced at C5–C6. Note the long segment T2 hyperintensity within the anterior horns
The owl-eyes sign, also referred to as snake-eyes sign or fried-eggs sign, represents bilaterally symmetric circular to ovoid foci of high T2-weighted signals in the anterior horn cells of the spinal cord and is seen on axial MR imaging. The sagittal corollary is a "pencil-like" vertical linear high T2-weighted signal extending usually over a number of segments.
Although typically described as one of the patterns in spinal cord infarction affecting the anterior spinal artery , it is seen in multiple other clinical settings and represents the result of increased metabolic activity (thus vulnerability) and reduced collateral supply of the anterior horns of the spinal cord.
This pattern is seen in the following scenarios :
- anterior spinal artery ischemia: common
- chronic compressive myelopathy: common
- spondylotic
- due to ossification of the posterior longitudinal ligament (PLL)
- Hirayama disease
- amyotrophic lateral sclerosis (ALS)
- neuromyelitis optica (NMO): uncommon
- poliomyelitis-like syndrome: rare
- Hopkins syndrome: rare
- spinal muscular atrophy: rare
Siehe auch:
Assoziationen und Differentialdiagnosen zu snake eye appearance:
