RAD-2. Comparison of radiographic techniques to optimize image analysis for evaluating traumatized bone using a rat as a model.

The search for an ideal, safe, efficient and cost-effective protocol to assess progress in osteogenesis is on the rise. The specific objective of this investigation was to employ various combinations of radiographic techniques to optimize image analysis in orthopedic setting. Surgically induced femoral fractures immobilized by metallic plates and screws in adult male laboratory rats were used as a model (n = 50). The techniques were utilized to study the excised fractured femoral specimens. Specifically, conventional radiographic methods as well as those that are used for specimen radiography in clinical methods were utilized. For routine radiography, a portable x-ray machine was used and a Faxitron was used for specimen radiography. Exposure factors (Kvp, Mas), type of film, and magnification were varied in the experiments using Faxitron. Two clinical film mammography machines were employed for all selected excised femurs. To obtain object magnification the distance between the film and the object was varied to bring the object closer to the x-ray tube. An aluminum wedge [standard density 1.98 gm/c[m.sup.3] was included in the radiographs along with the specimens to obtain density measurements. The criteria to evaluate the images included (1) visualization of the immobilizing hardware; (2) evaluation of the fracture site; (3) evaluation of the rest of the bone specimen; and (4) evaluation of the soft tissues. Images obtained with the portable radiographic equipment showed the least amount of spatial and contrast resolution while the results obtained with Faxitron and the mammographic machines showed much higher contrast and spatial resolution. Optimal soft tissue resolution was difficult to obtain with any of the techniques.

Rishi Roy, Michelle Tucci, Ramesh Patel, George Russell, Audrey Tsao, and Hamed Benghuzzi, University of Mississippi Medical Center, Jackson MS.