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Re: Cisterna Magna. nucal foldFrom: James S Smeltzer MD (gaperina@mindspring.com)Fri Aug 14 12:04:00 1998
At 08:51 PM 8/11/1998 -0700, you wrote: >Correct me if I'm wrong. The cisterna magna, should measure at least 4 >mm, but not more than 10 mm. > >1. If less than 4mm, what condition might be suspected & what other >body parts would I find irregularities? > Neural tube defects below and Arnold-Ciari type II posterior rotation of the brain and descent of the cerebellum into the foramen magnum is present in about 90% (Crane) or more (personal experience) of open spina bifida, and may be the most easily apparent sonographically.
>2. If more than 10 mm, the same above questions. A small cerebellum (Measure trasnverse diameter) is more significant. The cisterna magna is larger when the cerebellum is hypoplastic, or appears large when there is a dandy-Walker cyst, or missing vermis. These are also associated with a high risk for retardation and other problems.
>3. In measuring the c.m. sometimes there is a connection tissue from This is a structure that is normally present and not always seen. Play with the gain and angle and you will more often see it. This also DOES NOT COUNT AS NEURAL TISSUE when assessing for presence in an occipital encephalocele - which has a drastic relation to outcome (NO tissue <10% adverse outcome, ANY tissue >90% severe impairment). Age affects the ability to see through the skull and placement.
> No.
>Nucal fold should measure no wider than 4 mm. If wider, what is Nuchal fold should be less than 3mm prior to 14 weeks. From 2/3 to 5/6 of Downs & other aneuploidy at 12-14 weeks will be identified by this simple finding.
Less than 6 mm at 16+ weeks. A few aneuploidies detected this way. LOOK
EARLY!
> What is the significance of a 2 vessel cord? 20% have chromosomal problem. 2 in five have a significant anomaly of heart or other structure. Some of these have renal agenesis on the side of the missing vessel.
>Years ago, an OB doctor ordered a kidney u/s on a 3 month old baby that Now you know why, NH0
>What is the significance of cysts in the cerebellum? How are they These Dandy-Walker cysts are usually midline or 4th ventricle. Check this out for more info. Good luck! Jim Smeltzer (gaperina@mindspring.com) http://www3.ncbi.nlm.nih.gov/htbin-post/Omim/dispmim?220200 Neuro : Dilated fourth ventricle Hydrocephalus Bulging occiput Cranial nerve palsies Nystagmus Truncal ataxia Radiology : Elevated imprint of the transverse sinuses Thinning and bulging of posterior fossa bones Partial or complete absence of cerebellar vermis Posterior fossa cyst at the fourth ventricle Inheritance : Autosomal recessive cases heterogeneous
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