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← Section I · Physical Principles, Instrumentation, Examination Principles
I.N

Three-Dimensional Echocardiography

5 cards

Notes

Modes

  • Real-time (live) 3D - single-beat acquisition, lower temporal/spatial resolution.
  • Multibeat (ECG-gated) full-volume - stitches 2–7 cardiac cycles into a larger, higher-resolution volume. Susceptible to stitch artifact with irregular rhythms (AF, PVCs) or respiratory motion.

Key clinical uses

  • Mitral valve anatomy - surgeon's-eye view; prolapse localization by segment.
  • Prosthetic valve dehiscence - 3D TEE is the gold standard.
  • LV and RV volumes / EF - 3D reduces geometric assumptions; correlates better with cMRI than 2D biplane (which underestimates volumes and doesn't foreshorten well).
  • LV mass - measured directly (no geometric assumption vs. M-mode / 2D formulas).
  • LA volume, RV assessment, congenital anatomy (ASD/VSD morphology).
  • Structural interventions - TAVR, MitraClip, LAA closure, PFO/ASD closure - real-time 3D TEE guidance.

Advantages over 2D

  • Direct volumetric measurement.
  • Better correlation with cardiac MRI.
  • Improved reproducibility.
  • Comprehensive assessment of complex valvular anatomy.

Limitations

  • Lower spatial and temporal resolution than 2D.
  • Stitch artifact in multibeat acquisition (arrhythmia, apnea required for optimal quality).
  • Longer acquisition and analysis time.
  • Requires higher endocardial definition - contrast may help.

Volumetric technique pearls

  • LV volumes measured by 3D are larger than 2D biplane and closer to MRI. EF is similar.
  • 3D LA volume assessment recommended when available.

Cards

  • basicI.N-001
    What is 'stitch artifact' in 3D echo?
    → An acquisition artifact from multibeat/ECG-gated 3D volumes. When the patient's rhythm is irregular (AF, PVCs) or respiration varies between cycles, the stitched segments misalign.
  • basicI.N-002
    Real-time (single-beat) vs multibeat 3D — trade-off?
    → Single-beat: lower spatial/temporal resolution but immune to stitch artifact. Multibeat: better resolution but requires stable rhythm and breath-hold.
  • basicI.N-003
    Why is 3D echo the gold standard for mitral annuloplasty ring dehiscence?
    → It offers a direct en-face 'surgeon's view' of the entire mitral annulus and the perimeter of the prosthesis, showing paravalvular dehiscence locations that 2D cannot fully appreciate.
  • basicI.N-004
    How do 3D-derived LV volumes compare with 2D biplane and cMRI?
    → 3D LV volumes are larger than 2D biplane (which foreshortens the apex) and closer to cMRI. EF is similar between modalities.
  • basicI.N-005
    How does 3D echo measure LV mass?
    → Directly, without geometric assumptions (unlike M-mode or 2D-linear methods, which assume ellipsoid LV shape).