Volume Measurements by Three‐dimensional Ultrasound
Pp. 35-45 (11)
Edward Araujo Junior, Luciano Marcondes Machado Nardozza and Wellington de Paula Martins
One of the first applications of three-dimensional ultrasonography (3DUS) in
gynaecology and obstetrics was for measuring volume. Previously, volume was
measured by two-dimensional ultrasonography (2DUS) assuming that the scanned
object was a regular structure like an ellipsoid. With the advent of 3DUS at the
beginning of the 1990s, volumetric measurement became more reliable because 3DUS
permitted the outer surface of the structure to be assessed, unlike 2DUS, which used
mathematical formulas. The first technique available was the multiplanar method or
planimetry, which consisted of volume assessment using the three orthogonal planes (x,
y, and z). Later came virtual organ computer-aided analysis (VOCAL), a method that
assesses volume by rotating the object in question around an axis. More recently, two
new techniques have been introduced: extended imaging virtual organ computer-aided
analysis (XI VOCAL) and sonography-based automated volume count (SonoAVC). The
former consists of defining pre-established areas on the device screen, while the latter
measures the volume of liquid structures. In this chapter, we shall discuss the main
techniques of volumetric assessment using 3DUS in gynaecology and obstetrics.
Extended imaging virtual organ computer‐aided analysis, Volume
measurements, Multiplanar, Sonography-based automatic volume calculation,
Three-dimensional ultrasound, Virtual organ computer‐aided analysis.
Department of Obstetrics, Paulista School of Medicine - Federal University of Sao Paulo (EPM-UNIFESP), Rua Napoleao de Barros, 875, Vila Clementino, Sao Paulo - SP, Brazil.