3-DIMENSIONAL FREEHAND ULTRASOUND - IMAGE-RECONSTRUCTION AND VOLUME ANALYSIS

A system is described that rapidly produces a regular 3-dimensional (3 -D) data block suitable for processing by conventional image analysis and volume measurement software, The system uses electromagnetic spati al location of 2-dimensional (2-D) freehand-scanned ultrasound B-mode images, custom-built signal-conditioning hardware, UNIX-based computer processing and an efficient 3-D reconstruction algorithm, Utilisation of images from multiple angles of insonation, ''compounding,'' reduce s speckle contrast, improves structure coherence within the reconstruc ted grey-scale image and enhances the ability to detect structure boun daries and to segment and quantify features, Volume measurements using a series of water-filled latex and cylindrical foam rubber phantoms w ith volumes down to 0.7 mt show that a high degree of accuracy, precis ion and reproducibility can be obtained, Extension of the technique to handle ill vivo data sets by allowing physiological criteria to be ta ken into account in selecting the images used for reconstruction is al so illustrated. (C) 1997 World Federation for Ultrasound in Medicine & Biology.