US with extended field of view: Phantom-tested accuracy of distance measurements

To evaluate the accuracy of distance measurements obtained with the extende d-field-of-view (FOV) software of a commercially available ultrasonographic scanner, two custom-designed phantoms that allowed scanning of flat and cu rved surfaces were used. Five hundred forty measurements of various known d istances in the phantoms were made by three examiners using various transdu cers. Although minor differences were observed between operators and transd ucers, 99.4% (537 of 540) of the distance measurements were accurate within plus or minus 4%. This extended-FOV technology provides accurate measureme nts of large objects in vitro.