Fetal Echocardiogram Z Score Calculator 2

Clinical calculation aid

Fetal cardiac biometry, Doppler, and M-mode interpretation BETA

Enter gestational age and measured fetal echocardiographic parameters to calculate formal z-scores where published equations are available. Pattern recognition comments are generated from groups of abnormal z-scores and are intended to prompt differential diagnosis, not make a diagnosis.

Equation policy

Published equations are used for displayed z-score parameters. When a cited source explicitly reported no acceptable z-score model, this page uses a reference interpretation.

All calculations must be clinically confirmed before use. Estimated results support interpretation and do not replace physician judgment, image review, or comprehensive fetal echocardiography.

Dating inputs

Date of exam

Estimated due date

GA weeks

GA days

Enter gestational age directly, or use the date selectors to auto-calculate weeks and days.

Cardiothoracic ratio

Cardiac transverse diameter

Thoracic transverse diameter

CTR

CTR is flagged when greater than 0.50. Interpret with cardiac axis, chest size, rhythm, and extracardiac findings.

Actions

Ready.

Reference details

2D structures: Krishnan A, Pike JI, McCarter R, Fulgium AL, Wilson E, Donofrio MT, Sable CA. Predictive Models for Normal Fetal Cardiac Structures. J Am Soc Echocardiogr. 2016;29(12):1197-1206.

Doppler / M-mode: Gagnon C, Bigras JL, Fouron JC, Dallaire F. Reference Values and Z Scores for Pulsed-Wave Doppler and M-Mode Measurements in Fetal Echocardiography. J Am Soc Echocardiogr. 2016;29(5):448-460.e9.

Erratum policy: Gagnon et al. 2019 erratum is the correction source if a displayed or future-added coefficient conflicts with the original 2016 printed tables.

Ductal PI: Tulzer G, et al. Doppler echocardiography of fetal ductus arteriosus constriction versus increased right ventricular output. J Am Coll Cardiol. 1991;18(2):532-536.

Summary

0Computed formal z-scores

0Outside ±2

—GA used for equations

—DA PI reference status

Interpretation snapshot

—Left-sided structures

—Right-sided structures

—Chamber / systolic function

—Doppler overview

Z-score pattern analysis

No measurements entered yet. After calculation, this panel will summarize abnormal clustering patterns and possible diagnostic considerations.

Z-score graph

Visual display of entered z-scores. Values outside ±2 are flagged; values beyond ±4 are capped on the graph scale but preserved in the text output.

Enter measurements and calculate to generate a graph.

How to measure fetal echocardiogram parameters

Use the clearest still frame or cine loop, optimize magnification, and avoid oblique planes. Measurements should be performed on the same unit scale as the equation input. Valve and vessel dimensions are entered in millimeters unless otherwise specified.

EMR-ready interpretation

Click Calculate all to generate an EMR-ready summary.

How ductal PI is handled

Ductal PI is not shown as a formal z-score. Tulzer reported that ductal PI did not change with gestational age and presented it as mean ± 2 SD = 2.46 ± 0.52. This calculator therefore uses:

Reference standardized score = (Measured PI - 2.46) / 0.2605

Normal reference interval: 1.94 to 2.98. Lower values support possible ductal constriction; higher values can be seen with increased right ventricular output or a wide-open ductal flow pattern and must be interpreted with the waveform and velocities.