tag:blogger.com,1999:blog-37215995682223349052024-03-04T20:22:15.702-08:00A Fortuitous Concatenationof shadowsDanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.comBlogger62125tag:blogger.com,1999:blog-3721599568222334905.post-15931014970823313652013-10-03T17:53:00.001-07:002013-10-03T17:53:28.762-07:00Coarctation Prediction in Neonates With PDAIntroducing a JavaScript interpretation of the recently published "coarctation prediction model" from Vanderbilt University Medical Center. I particularly enjoy little challenges such as this one, issued by the authors of a recent JASE article: ... can be easily integrated into daily work flow by entering the CPM equation into a digital picture archiving and communication DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-9421460263118104662013-04-04T20:53:00.001-07:002013-04-11T16:58:01.835-07:00Lean body mass as a scaling variable in pediatric cardiologylean body mass prediction equations based on height, weight, age, and gender are now available, providing insights into the practice of scaling of cardiovascular parameters to body size.
Recent critical reviews of reference values for pediatric cardiology are frankly sobering: we don’t have many studies with sufficient numbers of patients to draw reasonable conclusions, and the statistical DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-24718315763327677332013-04-01T11:20:00.001-07:002013-04-01T11:20:33.796-07:00Pretty Useless Surface Chartsa quick update about newly available aortic root reference values. I read the fairly recent AJC article Normal limits in relation to age, body size and gender of two-dimensional echocardiographic aortic root dimensions in persons ≥15 years of age and struggled to make use of their “surface charts”- maybe you did too. Here is an example “surface” representing “aortic diameters” (I presume they DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-85686328614905043482013-02-05T18:45:00.001-08:002013-02-05T18:45:35.968-08:00On the Cusp?upcoming studies addressing the inadequacies of existing reference values for (adult) echocardiography NORRE Study ...due to the lack of consistency in current echocardiographic ‘reference values’, their use for clinical decision-making remains questionable. So reads the ‘background’ section of the upcoming NORRE study (NOrmal Reference Ranges for Echocardiography), enrolling subjects agedDanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-62553754146673682562013-01-18T08:16:00.001-08:002013-01-18T08:20:59.632-08:00The Why and How of... What the?Print is dead. When the editorial process of a peer-reviewed journal deteriorates as it does in the January JASE issue, then I think it is safe to say print is dead. What was destined to be The editorial concerning z-scores for echocardiography will now only make sense if we read the coming errata, which diffuses the point entirely. I considered writing a letter to the editor, but it is not DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-37170939859563388122012-12-13T06:59:00.001-08:002012-12-13T06:59:56.636-08:00Scaling in Echocardiography: PsychosisA recent editorial states “In terms of practicality, developing normative values of right-heart dimensions by indexing to BSA is an important first step and should be encouraged.” If by “encouraged” they mean “discouraged and abandoned” then I totally agree. An editorial in the December JASE discusses recent additions to the body of knowledge concerning reference values for the right ventricle:DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-19299719756089668842012-11-24T09:31:00.001-08:002012-12-09T22:03:51.486-08:00LVEDV Z-ScoresThe second of two recent updates to app.parameterz.com is the addition of the left ventricular volume and dimension data supplied by this recent article:
Normalized end-systolic volume and pre-load reserve predict ventricular dysfunction following surgery for aortic regurgitation independent of body size.
Gentles TL, French JK, Zeng I, Milsom PF, Finucane AK, Wilson NJ.
JACC DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-80125973845358304842012-11-23T11:07:00.001-08:002012-11-24T10:33:48.762-08:00Left Atrial Volume Z-ScoresCalculating BSA-adjusted z-scores of LA volume using an allometric equation
The first of two new calculations added to app.parameterz.com is based this recent article:
Normal values of left atrial volume in pediatric age group using a validated allometric model.
Bhatla P, Nielsen JC, Ko HH, Doucette J, Lytrivi ID, Srivastava S.
Circ Cardiovasc Imaging. 2012 Nov 1;5(6):791-6.DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-55242862798778689192012-03-23T09:10:00.001-07:002012-03-23T09:56:48.349-07:00Fetal Tissue Doppler Z-ScoresReference values and z-score calculations for fetal tissue Doppler E, A, and S waves added to new fetal echo z-score app. I just wrapped up the design and implementation of a new fetal echo z-score site (fetal.parameterz.com) and as a test of the new modular design, I added the fetal tissue Doppler data from this recent article: Gestational age- and estimated fetal weight-adjusted reference DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-71951143689570751552012-03-04T20:59:00.000-08:002012-03-05T21:26:45.770-08:00The Problem with Indexing Volumes to BSAWherein the inappropriate indexation of cardiac volumes to BSA is explored, this time with charts!
For some time now I have been aware of and abiding by the following words of caution:
linear dimensions and volumes have a nonlinear relation to surface area and
are more appropriately indexed by surface area to the 0.5 and 1.5 power, respectively.
-- Gutgesell and Rembold, Am J DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-33075877873567852222011-12-21T21:31:00.001-08:002011-12-21T21:35:11.889-08:00CMR LVEDV Z-Score Mini-Smackdownexamining CMR references for LVEDV reveals interesting differences; doubt is cast upon the practice of generating z-scores for indexed values I have been tinkering with z-scores for cardiac MRI and I thought it might be interesting to compare a couple of references for LV end-diastolic volume (I always think this stuff is interesting): Alfakih et al., (JMRI, 2003) Buechel et al. (JCMR, DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-41894421356058661672011-10-29T21:25:00.000-07:002011-10-29T21:25:31.514-07:00BSA Methods and Cardiac Z-ScoresA spreadsheet comparing different BSA calculations on various patients-- and the resulting BSA-adjusted z-scores-- reveals negligible differences.
Can we compare z-scores from various references when the methods for calculating BSA are different? How?
If a given group of z-score equations are BSA adjusted, and a given patient has a different BSA depending on the BSA formula, how do you DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-11795252359244979832011-06-26T10:22:00.000-07:002011-06-26T10:39:06.691-07:00Estimating Pulmonary Artery Pressure from Acceleration TimeCalculate PA pressure using pulmonary artery Doppler acceleration time.PA Acceleration Time (msec):
Estimated PA Pressure:
MethodsDoppler interrogation of the pulmonary artery was performed in the parasternal short axis view, with the pulsed-wave sample volume placed at the annulus of the pulmonary valve. The acceleration time was defined as the interval between the onset of systolic DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-54963094332467495432011-03-19T23:40:00.001-07:002011-03-19T23:49:08.737-07:00Aortic Root Reference Values ChartsA little decoration for the aortic root z-score calculator: charts. Charts add a little ‘sugar’ to the reporting of the aortic root z-scores, by adding an important visual element to the situation. I have tinkered with charts for the aortic root before, with a few ‘smack-down’ pages, but this is the first large-scale incorporation of the charts with the z-score calculator (well, that’s not DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-75747024547018839952011-03-13T09:41:00.001-07:002011-03-13T14:46:32.939-07:00Aortic Root and LV Volume Z-Score CalculatorsTwo new z-score calculators on Parameterz.com plus a paradigm shift or two First, the z-score calculators: LV End-Diastolic Volume z-scores, using the 5/6 A-L method A consolidated Aortic Root z-score calculator The paradigm shifts are these: All calculations are now server-side, using Python The Aortic Root calculator is a prototype for combining all available references intoDanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-4815724072176357782011-01-20T23:07:00.001-08:002011-01-20T23:07:08.749-08:00Reference BenchmarksA look at evolving benchmarks for pediatric cardiac reference data I read with some interest the article Optimal Normative Pediatric Cardiac Structure Dimensions for Clinical Use and was amused to see an off-hand reference to Parameter(z): Pettersen et al’s paper does not specify which BSA formula was utilized; however, the cardiac dimensions they measured have been normalized using both DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-37422926692374600732011-01-12T18:10:00.001-08:002011-01-12T20:46:37.620-08:00Q and A with Frédéric and NagibThe January issue of JASE holds this gem of a manuscript:
New equations and a critical appraisal of coronary artery Z scores in healthy children.
Dallaire F, Dahdah N.
J Am Soc Echocardiogr. 2011 Jan;24(1):60-74. Epub 2010 Nov 13.
The title couldn’t be any more fitting-- it is a must-read for anyone interested in the matter of z-scores for pediatric cardiology.The authors DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-68443489318929625172010-12-27T08:53:00.000-08:002010-12-27T08:53:00.175-08:00Calculating Aortic Regurgitant FractionUsing the echocardiographically obtained parameters of vena contracta width and abdominal aorta flow VTI’s to estimate the severity of aortic insufficiency. The recent article An echocardiographic model predicting severity of aortic regurgitation in congenital heart disease presents an interesting model for predicting aortic regurgitation severity. Using MRI as their gold standard, the authors DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-81726375519109529292010-05-03T23:09:00.001-07:002010-05-03T23:09:13.714-07:00Prototyping A Simple Database for Pediatric Echo Normal ValuesA mashup of Google technologies to create a free, simple, open-access database. The upcoming ASE Guidelines ”Recommendations for Quantification Methods During the Performance of a Pediatric Echocardiogram”, is intended to serve as The Standard for measurement techniques in pediatric echo. Getting everyone on the same page as far as making measurements is a prerequisite for moving forward with DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-36322863785995844852010-04-21T13:55:00.001-07:002010-04-21T14:00:44.634-07:00Kawasaki Disease Aneurysm Z-Scores: Another SmackdownBoston Children’s versus Children’s National Medical Center for a “giant” knockout When the Children’s National (CNMC) coronary artery z-score equations were published in 2008, I briefly compared them to the 2007 Boston data and noted their similarities. In my opinion, the manner in which the CNMC equations handle the “standard deviation” makes these incompatible with some newly proposed cutoffsDanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-63488715005209926442010-03-27T20:06:00.001-07:002010-03-27T20:06:51.622-07:00Aortic Root Z-Scores part deux A new z-score calculator for the aortic root (annulus, sinuses of valsalva, sinotubular junction, ascending aorta) is now available at ParameterZ.com. In addition to the online z-score calculator I have also created: an example calculation walk-through a sinuses of valsalva z-score comparison an ascending aorta z-score comparison Caveats A couple of things worth mentioning DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-37239825603846385632010-03-14T18:01:00.001-07:002010-03-14T18:03:32.030-07:00Adjusting for sizeA recent article includes a cameo appearance by none other than ParameterZ.com: Method 5: z-scores of LVM indexed for height2.7 were calculated as described in a recent publication which is accessed using an online calculator at http://parameterz.blogspot.com/2008/09/lv-mass-z-scores.html (accessed 6 April 2009). Incidence of left ventricular hypertrophy in children with kidney disease: DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-37741777135755886632010-02-07T08:32:00.001-08:002010-02-07T08:33:05.423-08:00Doppler Normal Values for Prosthetic ValvesSearchable, sortable normal Doppler values for aortic and mitral valve replacements. Around the echo lab we are politely referring to the recent JASE Guideline Recommendations for Evaluation of Prosthetic Valves as "the Beast". Both for the size of the article (40 pages!) as well as the onus of now having to perform a more exhaustive evaluation on our valve replacement patients. We DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-89748847165258949982010-01-03T07:42:00.001-08:002010-02-07T06:57:47.795-08:00New Fetal Echo Z-Score ReferencesNew fetal cardiac z-score equations from William Beaumont Hospital; new online calculator at OBSONO.orgFollowing up on their abstract from earlier this year, the group at William Beaumont Hospital in Royal Oak, Michigan produced what turns out to be the largest cross-sectional study of normative data for fetal cardiac measurements of all time:Fetal echocardiography: z-score reference ranges for aDanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0tag:blogger.com,1999:blog-3721599568222334905.post-70316149818487328982009-11-29T11:39:00.001-08:002016-11-28T17:13:20.835-08:00Pediatric RV Function (TAPSE) Z-Score CalculatorZ-Scores for RV systolic function. Using data published in the June 2009 JASE, this calculator determines the age-adjusted Tricuspid Annular Plane Systolic Excursion (TAPSE) z-scores: Notes: For the purpose of calculating the z-score, I used the published mean and "-3SD" lower limit to calculate each SD ([mean – lower limit] / 3)- which is a little bit off-label. That is, the DanDanhttp://www.blogger.com/profile/03896328643683228349noreply@blogger.com0