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3 years ago @ http://fetal.parameter... - Feedback | fetal.param... · 0 replies · +1 points

Great tip- thanks!

I will look into this directly.

4 years ago @ Parameter(z) - M-Mode Z-Scores · 0 replies · +1 points

there are a few z-scores for various cardiac volumes; I mostly rely on google for indexing. Try doing a google search for "volume" or "thickness" with the additional search term of "site :www.parameterz.com"

5 years ago @ Parameter(z) - TAPSE RV Function Z-Sc... · 0 replies · +7 points


No, there are no prediction equations for this. But, you should be able to do multiple if..then statements to get the z-scores (that what I did for our install)

You can read a post about how-to here: http://fortuitousconcatenation.blogspot.com/2009/...


6 years ago @ http://fetal.parameter... - Feedback | fetal.param... · 0 replies · +1 points


I just recently added the data from Gagnon et al., that includes m-mode wall thickness data. It is not included in the main app because that was designed for 2D measurements...

You can find the Gagnon z-scores here: http://fetal.parameterz.com/gagnon

6 years ago @ Parameter(z) - About · 0 replies · +8 points

Tha BSA-adjusted z-scores for the aortic valve, aortic root, and aortic arch — developed specifically for Turner syndrome patients — can be found only on the main site: http://www.parameterz.com/refs/quezada-ajmg-2015

7 years ago @ A Fortuitous Concatena... - Aortic Stenosis: Calcu... · 1 reply · +1 points

Ah, I see that this is broken. Looks like the Google Gadgets are not playing well with others...
Thanks for pointing that out :-)

Rather than troubleshoot why the dated tech stopped working, I have simply relocated the calculator.
It's new home is here: http://www.parameterz.com/tools/aortic-valve-area...

7 years ago @ Parameter(z) - About · 0 replies · +1 points


Thanks for the kind words!

Lots of people have made that same request; Blogger is not a great tool for doing these kinds of web things, so I have moved all development to a new site- incorporating this request as well as making other improvements. Please visit:

7 years ago @ Parameter(z) - About · 0 replies · +8 points

Excellent question.

The classification of disease based on echo measurement z-scores is something of a Holy Grail for pediatric cardiology. There is a paucity of research that associates outcome with z-scores.

You might find these articles interesting though:

* Distribution and Categorization of Echocardiographic Measurements in Relation to Reference Limits [http://circ.ahajournals.org/content/96/6/1863.full]

* Improved classification of coronary artery abnormalities based only on coronary artery z-scores after Kawasaki disease. [http://www.ncbi.nlm.nih.gov/pubmed/20024653]

* Reference values for echocardiographic measurements in urban and rural populations of differing ethnicity: the Strong Heart Study. [http://www.ncbi.nlm.nih.gov/pubmed/11391289]

I also pondered this very subject myself a while back: http://fortuitousconcatenation.blogspot.com/2008/...

7 years ago @ Parameter(z) - TAPSE RV Function Z-Sc... · 0 replies · +8 points

Great question. While they do indeed discuss the TAPSE vs. BSA relationship in the article, the way read it none of the supplied data can be used- or even modified such that it can be used- to generate BSA-adjusted TAPSE values.

The tabular TAPSE normal data is arranged by age. There are columns for mean, min, and max BSA for each age group, but there is so much overlap between BSA and age that the way the data is presented there is no way to sort that out. The authors also presented the idea of BSA "indexed TAPSE" values, but those are... age-specific.

To me, it seems totally clear that these values should be BSA adjusted. In fact, if what the TAPSE measurement is supposed to be telling us is something about RV function, I think that once you controlled for the size-related or growth-related changes the curve should actually be pretty flat.

8 years ago @ Parameter(z) - About · 0 replies · +1 points


I read the "MAPSE" paper.
I liked what they were trying to do with TAPSE: provide a measure of, and reference values for, RV systolic function.

However, I think both TAPSE and MAPSE are somewhat imperfect measures of function. They combine both linear dimension and motion. Plots of TAPSE or MAPSE "function" over age or BSA show nonlinear increases, hauntingly reminiscent of cardiac growth curves. Yet, the common understanding of systolic function is that it is actually fairly flat with age (if not inverted as compared to a TAPSE curve).

I am not convinced that LV systolic function increases with age, as demonstrated by the proposed MAPSE curves; I am fairly convinced that MAPSE vs. age reveals more about normal cardiac growth than it does about function.

In the case of the RV, those shortcomings can be tolerated somewhat because we have few other echo measures of RV sytolic function. Not so with the LV. Fractional shortening, ejection fraction, and deformation analysis are well established measures and, at least in children, fairly easy to obtain.

Published z-score equations for LV Fractional Shortening and EF are lacking. I wonder why the authors did not recognize that need...