The axolotl as an animal model for the comparison of 3-D ultrasound with plain film radiography

We assessed the usefulness of an animal model, the axolotl (Ambystoma mexic anum), in comparing 3-D ultrasound (3-D US) and plain him radiographs, Hind limbs were amputated from 5 animals, at either the zeugopodial or stylopodi al level, and each regenerating limb was imaged 16 times with 3-D US and 14 times with plain film X ray over 315 days. US images were acquired with a Siemens Sonoline Versa Pro(R) and a 10-MHz linear array transducer, For 3-D US images, the probe was translated in a motor-driven linear stage while i mages were digitized, The regenerating tibia and fibula bones were detected on 3-D US an average of 37 days earlier than on plain film radiography, an d regenerating phalangeal bones were detected on 3-D US an average of 18 da ys earlier, After 120 days, both imaging modalities consistently showed the bones. The average bone growth rates for the tibia and fibula were 0.019 /- 0.001 mm/day and 0.019 +/- 0.001 mm/day, respectively. (C) 1999 World Fe deration for Ultrasound in Medicine & Biology.