There have been reports on the use of Ultrasound (US) for monitoring fracture repairudand for measuring muscle volume. Change in muscle mass is a useful bio-marker forudmonitoring the use and disuse of muscle, and the affects of age, disease and injury.udThe main modality for imaging bone is X-ray and for muscle volume MagneticudResonance (MR). Previous studies have shown US to have advantages over X-rayudand MR. US can image all stages of the fracture repair process and can detect signsudof healing 4-6 weeks before X-ray allowing earlier detection of possibleudcomplications. Compared to MR, US is less resource intensive, easier to access andudalso has fewer exclusion criteria for patients.udDespite these advantages, the limited field of view that US can provide results inudhigh operator dependency for scan interpretation and also for length and volumeudmeasurements.udThree-dimensional Ultrasound (3D US) has been developed to overcome theseudlimitations and has been used to provide extended field of view images of the foetusudand the heart and to obtain accurate volume measurements for organs.udIn this thesis it is hypothesized that 3D US can provide a more comprehensiveudmethod of imaging fracture repair than X-ray and is also a viable alternative to MRudfor determining muscle volumes in vivo.udInitially, an electromagnetically (EM) tracked 3D US system was evaluated forudclinical use using phantom-based experiments. It was found that the presence ofudmetal objects in or near the EM field caused distortion and resulted in errors in theudvolume measurements of phantoms of up to ±20%. An optically tracked system wasudalso evaluated and it was found that length measurements of a phantom could beudmade to within ±1.3%.udFracture repair was monitored in five patients with lower limb fractures. Signs ofudhealing were visible earlier on 3D US with a notable, although variable, lag betweenudcallus development on X-ray compared to 3D US. 3D US provided a clearer view ofudcallus formation and the changes in density of the callus as it matured. Additionaludinformation gained by applying image processing methods to the 3D US data was used to develop a measure of callus density and to identify the frequency dependentudappearance of the callus.udVolume measurements of the rectus femoris quadricep muscle were obtainedudusing 3DUS from eleven healthy volunteers and were validated against volumeudmeasurements derived using MR. The mean difference between muscle volumeudmeasurements obtained using 3D US and MR was 0.53 cm3 with a standarduddeviation of 1.09 cm3 and 95% confidence intervals of 0.20 - 1.27 cm3udIn conclusion, 3D US demonstrates great potential as a tool for imagingudcomponents of the musculoskeletal system and as means of measuring callus density.
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