There are currently two options for calculating the Z-scores for common echo measurements using the PHN models: (1) with an online Z-score calculator; or (2) with a table listing the exponential power to be used with body surface area (BSA), the mean value of the indexed measurement, and the standard deviation (SD) of the indexed measurement.
The results from the PHN Echo Z-Score Project are available as a Z-score calculator here.
From the table below, you can take the values listed for the parameter of interest and use them along with the measurement value of the parameter and the BSA in the following formula to calculate the Z-score:
| Parameter | α | Mean | SD |
| MVAP | 0.50 | 2.31 | 0.24 |
| MVLAT | 0.50 | 2.23 | 0.22 |
| MVA | 1.00 | 4.06 | 0.68 |
| TVAP | 0.50 | 2.36 | 0.28 |
| TVLAT | 0.50 | 2.36 | 0.29 |
| TVA | 1.00 | 4.39 | 0.83 |
| ANN | 0.50 | 1.48 | 0.14 |
| ROOT | 0.50 | 2.06 | 0.18 |
| STJ | 0.50 | 1.69 | 0.16 |
| AAO | 0.50 | 1.79 | 0.18 |
| ARCHPROX | 0.50 | 1.53 | 0.23 |
| ARCHDIST | 0.50 | 1.36 | 0.19 |
| ISTH | 0.50 | 1.25 | 0.18 |
| LMCA | 0.45 | 2.95 | 0.57 |
| LAD | 0.45 | 1.90 | 0.34 |
| RCA | 0.45 | 2.32 | 0.55 |
| PVSAX | 0.50 | 1.91 | 0.24 |
| PVLAX | 0.50 | 2.01 | 0.28 |
| MPA | 0.50 | 1.82 | 0.24 |
| RPA | 0.50 | 1.07 | 0.18 |
| LPA | 0.50 | 1.10 | 0.18 |
| LVEDD | 0.45 | 3.89 | 0.33 |
| LVPWT | 0.40 | 0.57 | 0.09 |
| LVST | 0.40 | 0.58 | 0.09 |
| LVEDL | 0.45 | 6.31 | 0.46 |
| LVEDLEPI | 0.45 | 6.87 | 0.45 |
| LVEDA | 0.90 | 11.91 | 1.89 |
| LVEDAEPI | 0.90 | 20.00 | 2.59 |
| LVEDV | 1.30 | 62.02 | 11.94 |
| LVEDVEPI | 1.30 | 113.14 | 17.85 |
| LVM | 1.25 | 53.02 | 9.06 |
| LVMTV | 0 | 0.88 | 0.16 |
| LVTTD | 0 | 0.15 | 0.03 |
| LVSI | 0 | 1.63 | 0.17 |
What is the relationship between echo measurements and BSA?
The calculated regression equations from PHN data were:
Echo measurement = intercept + slope * BSAα
| Measurement | Alpha | Intercept | Slope |
| MV (AP) (cm) | 0.5 | 0.082924814 | 2.208397289 |
| MV (LAT) (cm) | 0.5 | 0.142783317 | 2.058261615 |
| MVA (cm2) | 1.0 | 0.196597638 | 3.757279658 |
| TV (AP) (cm) | 0.5 | -0.060825454 | 2.431341306 |
| TV (LAT) (cm) | 0.5 | 0.249147894 | 2.064415385 |
| TVA (cm2) | 1.0 | 0.186568091 | 4.117988499 |
| ANN (cm) | 0.5 | -0.016599775 | 1.506884773 |
| ROOT (cm) | 0.5 | 0.025841881 | 2.034421612 |
| STJ (cm) | 0.5 | -0.010501014 | 1.706720717 |
| AAO (cm) | 0.5 | 0.037633274 | 1.742197392 |
| ARCH (PROX) (cm) | 0.5 | -0.164254288 | 1.729068410 |
| ARCH (DIST) (cm) | 0.5 | -0.064930281 | 1.436019255 |
| ISTH (cm) | 0.5 | 0.060606576 | 1.182100289 |
| LMCA (mm) | 0.45 | 0.110674881 | 2.820117190 |
| LAD (PROX) (mm) | 0.45 | 0.052951441 | 1.839996768 |
| RCA (PROX) (mm) | 0.45 | 0.012047694 | 2.301336377 |
| PV (SAX) (cm) | 0.5 | 0.009528205 | 1.907058780 |
| PV (LAX) (cm) | 0.5 | -0.220768333 | 2.286834232 |
| MPA (cm) | 0.5 | 0.117718176 | 1.682071763 |
| RPA (cm) | 0.5 | -0.008988176 | 1.088778500 |
| LPA (cm) | 0.5 | 0.001348966 | 1.109745289 |
| LVEDD (cm) | 0.45 | 0.045047560 | 3.843553561 |
| LVPWT (cm) | 0.4 | -0.006805387 | 0.572766918 |
| LVST (cm) | 0.4 | 0.008416262 | 0.566410942 |
| LVEDL (cm) | 0.45 | -0.079863429 | 6.410199218 |
| LVEDL (EPI) (cm) | 0.45 | -0.067593474 | 6.950057220 |
| LVEDA (cm2) | 0.9 | 0.230577153 | 11.707701221 |
| LVEDA (EPI) (cm2) | 0.9 | 0.456500737 | 19.404203636 |
| LVEDV (cm3) | 1.3 | -0.378916534 | 64.201157201 |
| LVEDV (EPI) (cm3) | 1.3 | -1.416047154 | 116.66554843 |
| LVM (gm) | 1.25 | -2.652765755 | 57.253578598 |
| LVESD (cm) | 0.5 | 0.257530334 | 2.361910336 |
| LVESV (cm3) | 1.3 | -0.942421777 | 27.499070729 |
Parameter Abbreviations: AAO=ascending aortic diameter; ANN=aortic annular diameter; ARCHDIST=distal transverse arch diameter; ARCHPROX=proximal transverse arch diameter; ISTH=aortic isthmus diameter; LAD=proximal left anterior descending coronary artery diameter; LMCA=left main coronary artery diameter; LPA=left pulmonary artery diameter; LVEDA=LV (LV) short-axis end-diastolic endocardial area; LVEDAEPI=LV short-axis end-diastolic epicardial area; LVEDD=LV short-axis end-diastolic endocardial diameter; LVEDL=LV long-axis end-diastolic endocardial length; LVEDLEPI=LV long-axis end-diastolic epicardial length; LVEDV=LV short-axis end-diastolic endocardial volume; LVEDVEPI=LV short-axis end-diastolic epicardial volume; LVM=LV mass; LVMTV=LV mass-to-volume ratio; LVPWT=LV short-axis end-diastolic posterior wall thickness; LVSI=LV sphericity index; LVST=LV short-axis end-diastolic septal thickness; LVTTD=LV thickness-to-dimension ratio; MPA=main pulmonary artery diameter; MVAP=mitral anteroposterior diameter; MVLAT=mitral lateral diameter; MVA=mitral area; PVLAX=pulmonary annular long-axis diameter; PVSAX=pulmonary annular short-axis diameter; RCA=proximal right coronary artery diameter; ROOT=aortic root diameter; RPA=right pulmonary artery diameter; STJ=sinotubular junction; TVAP=tricuspid anteroposterior diameter; TVLAT=tricuspid lateral diameter; TVA= tricuspid area.
Measurement Abbreviations: AAO = ascending aortic diameter; ANN = aortic annular diameter; ARCH (DIST) = distal transverse aortic arch diameter; ARCH (PROX) = proximal transverse aortic arch diameter; ISTH = aortic isthmus diameter; LAD (PROX) = proximal left anterior descending coronary artery diameter; LMCA = left main coronary artery diameter; LPA = left pulmonary artery diameter; LVEDA = left ventricular (LV) short-axis end-diastolic endocardial area; LVEDA (EPI) = LV short-axis end-diastolic epicardial area; LVEDD = LV short-axis end-diastolic endocardial diameter; LVEDL = LV long-axis end-diastolic endocardial length; LVEDL (EPI) = LV long-axis end-diastolic epicardial length; LVEDV = LV short-axis end-diastolic endocardial volume; LVEDV (EPI) = LV short-axis end-diastolic epicardial volume; LVM = LV mass; LVPWT = LV short-axis end-diastolic posterior wall thickness; LVESD = LV short-axis end-systolic diameter; LVESV = LV end-systolic volume; LVSI = LV sphericity index; LVST = LV short-axis end-diastolic septal thickness; MPA = main pulmonary artery diameter; MV (AP) = mitral annular anteroposterior diameter; MV (LAT) = mitral annular lateral diameter; MVA = mitral annular area; PV (LAX) = pulmonary annular long-axis diameter; PV (SAX) = pulmonary annular short-axis diameter; RCA (PROX) = proximal right coronary artery diameter; ROOT = aortic root diameter; RPA = right pulmonary artery diameter; STJ = aortic sinotubular junction; TV (AP) = tricuspid annular anteroposterior diameter; TV (LAT) = tricuspid annular lateral diameter; TVA = tricuspid annular area.