Calculate the z-scores of 21 common 2D and M-Mode echo measurements, related to body surface area. Measurement sites include the mitral valve, left ventricle, aortic valve, aortic arch, pulmonary valve, and pulmonary arteries. Data is from 782 patients evaluated at the Children's Hospital of Michigan.
References
Regression equations for calculation of z scores of cardiac structures in a large cohort of healthy infants, children, and adolescents: an echocardiographic study. Pettersen MD, Du W, Skeens ME, Humes RA. J Am Soc Echocardiogr. 2008 Aug;21(8):922-34.Comments
On Saturday Apr 19 2008, Dan
said: version 0.1, April 19 2008
On Tuesday Apr 22 2008, Dan
said: version 0.2 constrained the calculations to subjects with BSA < 2.0. See
this post.
On Thursday May 01 2008, Rick Jensen
said: Very easy and helpful; feels trustworthy. I thought there were ascending aortic
values?
On Thursday May 01 2008,
Dan said: Curiously, the AAO did not make it into this publication, but
they did include aortic measurements like the "distal aortic arch" and "aorta
at diaphragm" ... Go figure.
On Sunday May 25 2008, Yael
said: Excellent job!! One thing though, It is easier to have the results as you
enter the numbers kike un the coronary artery section and not to hit the calculate
button. Yael
On Sunday May 25 2008,
Lloyd Marks said: Although I can access your site on my Treo, I can't run
the application. Any way to create an application that would allow you to do this
on a Treo nor other PDA. One idea - Perhaps you could get Epocrates to add this
to their medmath functions. Maybe they would even pay you for it.
On Sunday May 25 2008,
Dan said: @ Yael: Good point- it is quite cumbersome at this point. I only
recently figured out JavaScript and it's "onChange" event... Updating this calculator
is now on my "to do" list. @Dr. Marks: You are way ahead of the curve there on your
Treo. This site was developed primarily as a tool for our echo lab- as an extension
to our report writing software. Considerations for mobile devices never entered
the picture.
On Monday May 26 2008, John Plowden said: Great job Dan. Would be nice to have the
option of entering the weight in pounds and oz and the length in inches and have
the program convert it automatically. Just a thought, probably would not be too
hard to do. Thanks again for all of your efforts
On Tuesday May 27 2008, Giacomo Pongiglione
said: Well done. Thanks.
On Tuesday May 27 2008,
Dan said: Thanks for the kind words. @ Dr. Plowden: We can't afford to
lose another Mars Explorer. *grin* I thought the International System
was the standard for reporting height and weight units of measure, no?
On Wednesday May 28 2008, Jorge Gomez said: Seams accurate. Very Helpful!!!
On Thursday May 29 2008, Richard W Gratian, M.D. said: We started using your calculator
today. It is very convenient but unfortunately, the upper limit appears to be 2.0
m2 which we found out with our third patient. Is there a calculator for patients
above 2.0 m2? Thanks. Rick Gratian
On Thursday May 29 2008,
Dan said: Dr. Gratian: You raise an interesting point. Shortly after I built
this calculator and starting using it myself, I noticed some unbelievable results on patients with BSA
> 2.0 m2. I went back to the article and sought the descriptive characteristics
of their patient population. These descriptive characteristics were missing from
the article. (as of right now, this article is still an "In Press Corrected
Proof" so I suppose the information could yet be added). The supplied figures
for the article top out at 2.0 m2, so I chose to constrain the calculations at this
limit. Thanks for your comments!
On Friday May 30 2008,
Dan said: modified the calculator to update the z-scores as the data is
entered
On Wednesday Jun 04 2008, bleb said: entering Z-values for ascending aora (after
ST junction) would be helpful. e.g. Bic Ao valve, Turner S.
On Thursday Jun 05 2008, giacomo said: Did you ceck the equations and the coefficients
provided in your paper? The result of your equation 2 is -0.384 (how can a negative
value be the mean?) while it should be 0.68. On the other end, if you enter 0.68
as Mean y into equation 4 the resulting z value is not - 2.48
On Thursday Jun 05 2008,
Dan said: Bleb: the authors did not include data for the AAO- I can't answer
as to why... Dr. Pongiglione: the results of "equation 2" in the article refers
to the natural log-transformed predicted value. To get the value (y) back in the
original units, it needs to be back-transformed, i.e. e raised to the power
y; the JavaScript equivalent is Math.exp(y) I hope this helps.
On Tuesday Jun 17 2008, kalyani trivedi said: fantastic; now I can be very precise
with ease. Thank you very much for putting this together.
On Thursday Jun 19 2008, Volker Petersen said: This ist what I was looking for a
long time, thank you
On Friday Jun 20 2008, satish adwani said: Excellent! Keep it up. Very helpful.
I always keep it on when I do Echo's in my clinic!
On Wednesday Jul 23 2008, Marcos said:
On Friday Jul 25 2008, Peter said: Thank you very much. Not only I have waited such
a long time for an easy way to get these data calculated for each of our patients.
On Thursday Jul 31 2008, MARIO CAZZANIGA said: do you have Z score calculations
of magnetic resonance: RVEDV, RVESV, LVEDV, LVESV, RVEF, LVEF ?
On Thursday Jul 31 2008,
Dan said: Mario: Sorry, my primary focus has been on reference values for
pediatric echocardiography.
On Monday Aug 04 2008, Jan du Plessis said: This is an extremely useful site
On Thursday Aug 07 2008, ayse sarioglu said: This an extremely useful site.Thank
you very much for your excelent work.
On Thursday Aug 14 2008, Dr Rezoana said: Would u please help us to find the Z score
of above mentioned psarameters
On Sunday Aug 31 2008, Keyhan Sayadpour, MD said: At Children's Medical Center,
Tehran, Iran, we routinely use this website. It is great and very helpful.
On Wednesday Sep 03 2008, shanthi sivanadam said: Would appreciate if you could
add Z-score/percentile .
4 comments:
added percentiles
Thank you Dan for the usefull information. I use the Detroit article. I wanted to ask how do you calculate the ranges?
The range is calculated as z scores of +/- 1.65 .
This is done is by solving the "known" and "unknown" values of the equation, i.e., to solve the z score equation for the (known) z score (eg "+1.65") to determine the (unknown) measurement.
HTH,
Dan
Too much spaghetti code!
I have upgraded the underlying code as described here.
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