An imaging plane, parallel to the ground, perpendicular (rotated 90°) to the long axis of the human body; the axial plane separates the superior from the inferior part (the head from the feet). Also called axial, transaxial or transversal plane.

A tri-frequency probe emits three different frequencies. Probes with tri-frequency capabilities allow a wide range of scanning applications from a single probe.

See also Multi-Frequency Probe and Dual Frequency Phased Array Transducer.

Triplex exam means the use of three ultrasound modalities in a single examination to study blood flow with gray scale imaging, color Doppler and spectral Doppler.

Triplication artifacts can occur through diffraction and refraction on intersections.