Download Introduction To Radiology

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
50
Computer Tomography (CT)



X-ray beam moved in a 360 degree arc
around patient to generated crosssectional 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