1. Two Other Densities in Plain Films Contrast media: bright white outline of the structure injected Contrast media: bright white outline of the structure injected  Barium sulfate Heavy metals: solid white Heavy metals: solid white  Artificial joints, pins, tooth fillings  Appear as white on radiographs

4. Contrast Enhanced Radiographs Arthrography: contrast agent injected into joint space and outlines internal structures Arthrography: contrast agent injected into joint space and outlines internal structures Myelography: injected into subarachnoid space of spinal cord to evaluate spinal cord, nerve roots, & dura Myelography: injected into subarachnoid space of spinal cord to evaluate spinal cord, nerve roots, & dura Angiography: injected into arterial or venous systems to evaluate the circulatory system. Angiography: injected into arterial or venous systems to evaluate the circulatory system. Diskography: Injected into nucleus pulposus Diskography: Injected into nucleus pulposus

5. 50

9. Computer Tomography (CT) X-ray beam moved in a 360 degree arc around patient to generated cross- sectional images (3-D eval) X-ray beam moved in a 360 degree arc around patient to generated cross- sectional images (3-D eval) Detectors digitize the images with computer technology; cross-sectional slices of the body are 1 + mm thick Detectors digitize the images with computer technology; cross-sectional slices of the body are 1 + mm thick Less complex & somewhat less expensive option alternative to MRI. Excellent imaging of bone and greatly reduces overlap of structures Less complex & somewhat less expensive option alternative to MRI. Excellent imaging of bone and greatly reduces overlap of structures

11. Nuclear Imaging Bone scans: Radiopharmaceuticals preferentially taken up by bone. Bone scans: Radiopharmaceuticals preferentially taken up by bone.  Hot spots indicate increased mineral turnover / increased metabolism  Stress fractures, osteomyelitis, bone tumors, arthritis, metabolic bone disease, trauma, bone growth or healing

13. Magnetic Resonance Imaging (MRI) No ionizing radiation No ionizing radiation Strong magnetic field in combo with radio waves cause protons of hydrogen nuclei to resonate Strong magnetic field in combo with radio waves cause protons of hydrogen nuclei to resonate Different tissues resonate at different intensities - - from which 3D images are extrapolated Different tissues resonate at different intensities - - from which 3D images are extrapolated Bright = high signal intensity Bright = high signal intensity Dark = low signal intensity Dark = low signal intensity

15. Magnetic Resonance Imaging (MRI) Major advantages of MRI: the evaluation of soft tissue and tumors Major advantages of MRI: the evaluation of soft tissue and tumors Signal intensities gathered at two times Signal intensities gathered at two times T1 signal: Fat is bright, fluid is dark (gray) T2 signal: Fluid is brighter, fat is dark (gray) Either signal: Cortical bone is dark gray to black (main diff from CT); but marrow is white