Tuesday, October 27, 2009
Friday, October 23, 2009
DISH diagnostic criteria include the following : Flowing calcifications and ossifications along the anterolateral aspect of at least 4 contiguous vertebral bodies, with or without osteophytes. Preservation of disk height in the involved areas and an absence of excessive disk disease. Absence of bony ankylosis of facet joints and absence of sacroiliac erosion, sclerosis, or bony fusion, although narrowing and sclerosis of facet joints are acceptable.
Lower thoracic spine involvement is typical of DISH, but the lumbar and cervical spine also can be affected. The left side of the spine typically is spared or less involved, which probably is attributable to the pulsating aorta.
Wednesday, October 21, 2009
Monday, October 19, 2009
Friday, October 16, 2009
Optic nerve glioma (also known as optic pathway glioma) is the most common primary neoplasm of the optic nerve. In 66% of NF-1 patients with optic nerve glioma, the growth involves the intraorbital optic nerve. In the absence of NF-1, the optic chiasm is most commonly involved, as is, less often, the intraorbital optic nerve. Optic nerve glioma may involve various portions of the retrobulbar visual pathway, including the optic nerve, chiasm, tracts, and radiations. Malignant lesions can invade the hypothalamus, basal ganglia, and internal capsule directly, or they may spread to the leptomeninges or subpial surfaces. On T1-weighted images, optic nerve gliomas are usually isointense to the cortex and hypointense to white matter. Invariably, the lesions are hypointense to orbital fat. On T2-weighted images, lesions demonstrate a mixed appearance that is isointense to hyperintense relative to white matter and the cortex. Following contrast administration, intense enhancement is common.
Wednesday, October 14, 2009
- Type I is injury more than 2 cm distal to biliary bifurcation.
- Type II is less than 2 cm from biliary confluence.
- Type III injury involves entire common hepatic duct and leaves confluence intact.
- Type IV is complete or partial destruction of biliary bifurcation.
Tuesday, October 13, 2009
Friday, October 09, 2009
Thursday, October 08, 2009
Epidermoids represent 0.2-1% of all intracranial masses. They arise from inclusion of epithelial remnants trapped during 3-5 weeks of fetal life (remember that choroid plexus are also formed from invagination of ectodermal tissues).
Intraventricular epidermoids are more in 4th ventricle followed by lateral ventricles.
More common in middle age; very rare in children
If ruptured, aseptic meningitis occurs.
Long T1 and T2 are due to keratin in solid crystalline state. Epidermoids have restricted ADC and complex FLAIR signal, unlike arachnoid cysts.
An expansive intraventricular lesion in lateral ventricle, iso-intense on T1-weighted image and hypo-intense on T2-weighted image with few cystic areas, demonstrating restricted diffusion suggestive of INTRAVENTRICULAR EPIDERMOID. Differential diagnosis includes Intraventricular Neurocytoma and Oligodendrogliomas but calcification is hallmark for their diagnosis. Case by- Teleradiology Providers
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