Two Other Densities in Plain Films Contrast media: bright white outline of

the structure injected Barium sulfate

Heavy metals: solid white Artificial joints, pins, tooth fillings Appear as white on radiographs

Contrast Enhanced Radiographs

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

Angiography: injected into arterial or venous systems to evaluate the circulatory system.

Diskography: Injected into nucleus pulposus

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Computer Tomography (CT) 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

Less complex & somewhat less expensive option alternative to MRI. Excellent imaging of bone and greatly reduces overlap of structures

Nuclear Imaging

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

Magnetic Resonance Imaging (MRI) No ionizing radiation 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

Bright = high signal intensity Dark = low signal intensity

Magnetic Resonance Imaging (MRI) Major advantages of MRI: the evaluation

of soft tissue and tumors 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