Re: Anomaly scan, Serum testing, Down Syndrome andLateralventricles
From: jworrall@alaska.net
Mon Jul 14 12:57:42 2008
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I shall try to measure the atrium of the lateral cerebral ventricle at 12-13
weeks, when I am doing a nuchal translucency and first trimester evaluation.
I have only measured the atria in the second trimester.
Allen
>----- Original Message -----
From: "DuBose, Terry" <DuboseTerryJ@uams.edu>
To: "Multiple recipients of list ULTRASOUND" <ultrasound@mail.obgyn.net>
Sent: Monday, July 14, 2008 8:50 AM
Subject: Re: Anomaly scan, Serum testing, Down Syndrome andLateralventricles
> Well... depends on the author. Callen's new textbook (5th edition) shows
> the BPD to be from 20 to 23 mm during the 13th week (13.2-13.8 weeks).
> My
> own measurements show the BPD to be 23 mm at 13 weeks, based upon several
> thousands of cases. We really don't have any precise measurements, and
> many
> refer to any fetus between 13.0 and 13.9 weeks, "as 13 weeks". This is
> the
> reason I have always advocated estimating fetal age to the 1/10 of a week,
> rather than just weeks or even weeks + days... it is easier to average the
> multiple fetal parameter ages after Hadlock's method.
>
> This really does not tell us the precise measurement, "I have a 33yr old
> gravida2, with 13 weeks pregnancy, scan done today shows mild
> ventriculomegaly...."
>
> It may be that because at 13 weeks the choroid plexus and lateral
> ventricles
> appear to fill the cerebral hemispheres that the "mild ventriculomegaly"
> call
> was made. Without measurements we can't argue the point.
>
> But I do believe that by the start of the 1st trimester, the lateral
> ventricular atria has reached 7-10 mm and remains that size as the head
> and
> cerebrum enlarges around them.
>
> Terry J. DuBose, M.S., RDMS, FSDMS, FAIUM
>
> Associate Professor & Director
> Diagnostic Medical Sonography Program
> University of Arkansas for Medical Sciences, CHRP
> 4301 West Markham St. Mail Slot #563
> Little Rock, Arkansas, 72205 USA
> 501-686-6510 or 501-686-5948
> DuBoseTerryJ@UAMS.edu
> http://www.uams.edu/chrp/sonography/
> http://www.obgyn.net/us/panel/panel.htm
> http://www.io.com/~dubose/
> ---------------------------------------------------------------
> P Please consider the environment before printing this e-mail
> ---------------------------------------------------------------
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> ---------------------------------------------------------------
>
> -----Original Message-----
> From: ultrasound@obgyn.net [mailto:ultrasound@obgyn.net] On Behalf Of
> James
> Smeltzer
> Sent: Friday, July 11, 2008 5:44 PM
> To: Multiple recipients of list ULTRASOUND
> Subject: RE: Anomaly scan, Serum testing, Down Syndrome
> andLateralventricles
>
> Just a comment that the normal 13 week BPD is 20. Even though the LVs are
> close to 10, as every cell in the brain must come from the wall of the
> tube,
> and few cells have been made yet, the whole cannot be greater (or less)
> than
> the sum of its parts.
> JSS
>
>>>> "DuBose, Terry" <DuboseTerryJ@uams.edu> 7/11/2008 6:06 PM >>>
> Not necessarily for 10 mm... 15 mm is too large at any age. However, at
> 13
> weeks the ventricles fill most of the cranium and appear to be huge
> compared
> to the rest of the head. The choroid appears to fill the hemispheres of
> the
> cranium at 13 weeks.
>
> I can't find a specific image with measurements at 13 weeks, but in Fetal
> Sonography, p. 431 there is a sonogram that shows the choroid plexus and
> lateral ventricles to be at 10 mm in width (the scale is on the image).
> Also, I found an image of a 13 week fetal head in Callen's latest edition
> (5th edition, p. 364) that show the structures and describe them as ", the
> intercrainal anatomy is dominated by the prominent choroid plexuses of the
> lateral ventricles."
>
> I don't know when the width of the lateral ventricles actually reaches
> 7-10
> mm, but it is during the end of the 1st trimester. The head then grows
> larger around the ventricles, which make them appear to become smaller,
> but
> they remain about <10mm in width throughout the rest of the gestation.
>
> Terry J. DuBose, M.S., RDMS, FSDMS, FAIUM
>
> Associate Professor & Director
> Diagnostic Medical Sonography Program
> University of Arkansas for Medical Sciences, CHRP
> 4301 West Markham St. Mail Slot #563
> Little Rock, Arkansas, 72205 USA
> 501-686-6510 or 501-686-5948
> DuBoseTerryJ@UAMS.edu
> http://www.uams.edu/chrp/sonography/
> http://www.obgyn.net/us/panel/panel.htm
> http://www.io.com/~dubose/
> ---------------------------------------------------------------
> P Please consider the environment before printing this e-mail
> ---------------------------------------------------------------
>
> ---------------------------------------------------------------
>
> -----Original Message-----
> From: ultrasound@obgyn.net [mailto:ultrasound@obgyn.net] On Behalf Of
> jworrall@alaska.net
> Sent: Thursday, July 10, 2008 12:52 PM
> To: Multiple recipients of list ULTRASOUND
> Subject: Re: Anomaly scan, Serum testing, Down Syndrome and
> Lateralventricles
>
> Thanks Dr. Smeltzer. Yes, I realize now that an atrium of 10-15 mm at 13
> weeks would mean the fetal head had to be enormous.
>
> Allen
>> ----- Original Message -----
> From: "James Smeltzer" <James.Smeltzer@wellstar.org>
> To: "Multiple recipients of list ULTRASOUND" <ultrasound@mail.obgyn.net>
> Sent: Thursday, July 10, 2008 1:44 AM
> Subject: Anomaly scan, Serum testing, Down Syndrome and Lateralventricles
>
>> Hi!
>>
>> All the cells of the CNS are lining cells of the wall of the tube that
>> started there, migrated out to their final position and did what they
>> were
>> supposed to do, based on where they came from and other factors.
>>
>>>From a CNS perspective we are all totally tubular!
>>
>> It only stands to reason that the starting mass of cells outside the tube
>> is small, and grows as more join them.
>>
>> This is the way of the tube.
>>
>> Allen, 10-15mm seems a bit generous for the LV tube diameter at the
>> atrium
>> at 13 weeks, since as the BPD is only 20mm and has to include one side of
>> the skull and the entire brain, and the two LVs are at a slightly
>> higher - and narrower - level of the brain (but still have SOME brain
>> substance at 13 weeks.
>>
>> A nuchal translucency of 2.6mm at 13 weeks (~CRL 67) is sufficient to
>> discuss/offer an amnio or CVS and fetal echo, or serum testing, tqargeted
>> sonogram (our preferred route), as the odds ratio for Down Synd is about
>> .75/.05. or about 15 fold the baseline age and other screening risk
>> (Snijders & al, Lancet 1998; 351:343-6). Yagel & al Ult. (Obstet. Gynecol
>> 11:262, 1998) come up with more conservative numbers, and if your normal
>> data fit their curve, you are right not to routinely offer an amnio to a
>> womal under 31, as their predicted nuchal lucency is 2.6 mm. (Odds ratio
>> of ~2 - not sure of their Down results).
>>
>> I am not recommending everyone rely as heavily on dysmorphology as we do,
>> as there is a learning curve, amnio is 100% (99.4%) reliable and we do a
>> ridiculously low number of amnios - with a ridiculously high positive
>> rate. But looking never killed a baby.
>>
>> I would definitely look for tricuspid regurgitation, brachycephaly -
>> which
>> can be seen early - short femur, and humerus, and an absent nose bone, at
>> least. Of course an AV septal defect alone would be sufficient to warrant
>> an amniocentesis. Personally, in our hands, serum markers have helped to
>> identify Down syndrome only once in the absence of a suggestive sonogram,
>> but have - with quad screen - gotten to an acceptably low false positive
>> rate, low enough to raise the odds, and significantly increase the
>> detection of Down syndrome in the absence of early careful sonography.
>>
>> Know your results and your normal curve for NL as these are essential for
>> interpretation of results. (I still do not understand how we get such
>> different normals. Maybe we should all take the same course;^)
>>
>> Hope this helps! Jim Smeltzer
>>
>> James S. Smeltzer, MD, FACOG, SMFM
>> Consultant, Maternal Fetal Medicine
>> Wellstar Physicians' Group
>> Northwest Women's Care
>> 787 Campbell Hill St
>> Marietta GA 30060
>> James.Smeltzer@wellstar.org
>> VM 678-290-3035
>> Off 770-528-0260
>> Page 404-318-3451
>>
>>>>> Terry DuBose <terrydubose@sbcglobal.net> 7/5/2008 2:14 PM >>>
>> I think Allen is correct, the ventricles often appear large early on, but
>> as the head grows up around them, they tend to look more normal... need
>> measurements later. Terry
>>
>> jworrall@alaska.net wrote: At 13 weeks a transvaginal scan will often
>> (but not always) permit a very
>> good view of the fetal head. I am not sure what "mild" ventriculomegaly
>> is,
>> but probably the atrium of the lateral cerebral ventricle measures
>> between
>> 10 and 15 mm. If a good view of the fetal head can be obtained, you would
>> be
>> able to evaluate the posterior cerebral fossa, and look at the posterior
>> end
>> of the occipital horn (is it rounded or pointed?) the cisterna magna, and
>> the cerebellum. Remember that this early in pregnancy the cerebellar
>> vermis
>> is not completely formed, so as you scan the posterior cerebral fossa
>> inferiorly, you may mistakenly think you have a Dandy Walker situation. I
>> am not sure you would see the cavum septi pellucidi that early.
>>
>> Hopefully, in addition to the nuchal translucency, the patient has been
>> able
>> to obtain the blood test part of that genetic screen, the PAPP-A and beta
>> hcg, so that you will get a proper evaluation of her risk of having a
>> baby
>> with Trisomy 21. I do NOT think mild ventriculomegaly and a nuchal
>> translucency of 2.6 mm would be an indication for amniocentesis or
>> chorionic
>> villus sampling but I guess that depends on where you practice and what
>> the
>> custom is in your location. As always, I hope Anita and Prathima will
>> comment.
>>
>> Allen
>>
>> --------------------------------------------------
>> From: "cjayankar" Sent: Saturday, July 05, 2008 3:16 AMTo: "Multiple
>> --------------------------------------------------
>> recipients of list ULTRASOUND"
>> --------------------------------------------------
>> Subject: anomaly scan
>>
>>> hello
>>>
>>> I have a 33yr old gravida2,with 13 weeks pregnancy,sacn done today
>>> shows mild ventriculomegaly and NT 2.6mm.Her first child is 7yrs old and
>>> autistic.No significant family or past history.
>>>
>>> Planning for anomaly sceening,can the mild ventriculomegaly be taken
>>> as very significant.
>>>
>>> Thank You
>>> jayankar
>
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