---

2D Echocardiography: How to Take Measurements

General Principles

• All measurements are taken on frozen (still) frames at specific points in the cardiac cycle (end-diastole or end-systole) triggered by the ECG.
• End-diastole is defined as the onset of the QRS complex.
• End-systole is the frame just before mitral valve opening (or the smallest LV cavity size).
• Electronic calipers are placed at the interface between myocardium and cavity (inner-edge or leading-edge depending on the parameter).
• The ASE/EACVI 2015 guidelines recommend inner-edge to inner-edge (IE-IE) methodology for most linear and aortic measurements.

---

Standard Views Used for Measurements

---

1. Left Ventricular Linear Dimensions (PLAX View)

• IVSd - Interventricular septal thickness in diastole (normal: 6-12 mm)
• LVIDd - LV internal diameter in diastole (normal men: 37-56 mm; women: slightly smaller)
• LVPWd - LV posterior wall thickness in diastole (normal: 6-12 mm)
• LVIDs - LV internal diameter in systole (same landmarks, taken at smallest cavity)

1. Obtain a clear PLAX view with the LV well-visualized.
2. Freeze at end-diastole (onset of QRS on ECG strip).
3. Place calipers perpendicular to the long axis.
4. Measure from the right side of the IVS to the left side of the posterior wall (inner-edge to inner-edge).
5. Repeat for LVIDs at end-systole.

2D-guided linear measurements from PLAX are preferred over M-mode to avoid oblique cuts of the ventricle.

---

2. LV Volumes and Ejection Fraction - Biplane Simpson's Method (Modified Simpson's Rule)

Steps:

• Ensure no foreshortening - the LV apex must be the true tip of the ventricle.
• In A4C: center the apex at the top of the sector; the septum and lateral wall should be equidistant.
• In A2C: rotate the probe ~60° from A4C until you see the inferior and anterior walls.

• Freeze at end-diastole (onset of QRS).
• Trace the endocardial border from one mitral annular point, around the apex, back to the other annular point.
• Exclude papillary muscles (trace around them or include them in the cavity).
• The machine divides the volume into 20 elliptical discs and sums them.
• Repeat in A2C.

• Freeze at end-systole (smallest cavity frame, just before mitral valve opens).
• Trace the endocardial border in both A4C and A2C.

EF (%) = [(EDV - ESV) / EDV] × 100

• LV EDV index: ≤74 mL/m² (men), ≤61 mL/m² (women)
• LV ESV index: ≤31 mL/m² (men), ≤24 mL/m² (women)
• Normal EF: ≥55%

---

3. LV Mass Calculation

LV mass (g) = 0.8 × {1.04 × [(LVIDd + IVSd + PWd)³ - LVIDd³]} + 0.6

• Men: 115 g/m² (linear method), 102 g/m² (2D method)
• Women: 95 g/m², 88 g/m²

---

4. Left Atrial (LA) Measurement

• LA diameter - measured in PLAX at end-systole, from the posterior aortic wall to the posterior LA wall (inner-edge to inner-edge).
• LA volume (preferred) - biplane area-length or biplane method of discs in A4C and A2C at end-systole. Upper normal: 34 mL/m².

---

5. Aortic Root / Ascending Aorta (PLAX View)

• Measured in end-diastole using inner-edge to inner-edge methodology.
• Key levels:
  • Aortic annulus
  • Sinuses of Valsalva
  • Sinotubular junction
  • Ascending aorta

---

6. Right Ventricular (RV) Measurements

• RVD1 - Basal RV diameter (maximal transverse diameter in the basal 1/3 of RV): normal ≤41 mm
• RVD2 - Mid RV diameter (at level of LV papillary muscles): normal ≤35 mm
• RVD3 - RV length (tricuspid annulus to apex): normal ≤83 mm
• RV free wall thickness - from subcostal view, at tip of anterior tricuspid leaflet, excluding trabeculations: normal ≤5 mm

• Measured in PSAX at the level of the aortic valve in end-diastole.
• RVOT proximal (RVOT1): from anterior aortic wall to RVOT free wall: normal ≤35 mm

---

7. Right Atrial (RA) Measurement

• RA area - planimetered in A4C at end-systole (largest RA frame). Upper normal: 18 cm².
• RA dimensions - minor axis ≤4.4 cm, major axis ≤5.3 cm.

---

8. IVC (Inferior Vena Cava) - Subcostal View

• Measured ~2 cm from the RA-IVC junction.
• Measure inner-edge to inner-edge at end-expiration.
• Normal: <2.1 cm; assess respiratory collapse for RA pressure estimation.

---

Key Technical Tips

1. Avoid foreshortening - especially in apical views. If the apex looks rounded, re-angle to find the true apex.
2. Gain settings - optimize to clearly define the endocardial border; avoid "blooming" artifacts that artificially thicken walls.
3. Frame rate - ensure adequate frame rate (>40 fps) for accurate end-systolic frames.
4. Multiple cardiac cycles - in atrial fibrillation, average measurements over 3-5 beats.
5. Measurements should be perpendicular to the structure being measured; angled cuts overestimate dimensions.
6. Papillary muscles and trabeculations - exclude from LV wall measurements and cavity tracings where possible.

---

Summary Table of Standard Measurements and Views

---