Medical Imaging

Question 1

• very short wave length electromagnetic waves (bones)
• dense structures = light areas
• hollow air (organs/fat) = dark areas
• used for = broken bones, breast tumors (mammography), bone density for porous bones (osteoporosis)
• not used for = soft tissue except for contrast medium (barium)
• cons = radiation exposure, 2D

Answer 1

X-Ray Imaging

Question 2

• computed reconstruction of x-ray images
• detailed cross-sectional pictures of body regions
• used for = bone images, soft tissue, and blood vessels
• less used for = nervous tissue and joint structure (knee/shoulder)
• cons = more radiation exposure than x-ray, could cause concern if used repeatedly

Answer 2

Computed Tomography Scans (CT)

Question 3

• visualizes blood vessels by x-ray or CT scans
  (angi = vessel)
• requires injection of x-ray absorbing contrast agent
• images form before and after injection of agent yield very clear images of blood vessels
• used for = detecting blood vessel abnormalities like blocked arteries supplying the heart
• cons = time-consuming, expensive, varying reactions to contrast agent

Answer 3

Digital Subtraction Angiography (DSA)

Question 4

• gamma rays are emitted by radioactively tagged tracer molecules that are injected into the body
• tracer molecule use depends on the reason for the scan
• uses radioactive glucose and florbetapir
• used for = detecting the spread of cancer, monitoring response to cancer treatment, helping diagnose Alzheimer’s, and exploring brain function
• cons = radiation exposure, relatively poor image resolution

Answer 4

Positron Emission Tomography Scan (PET)

Question 5

• uses powerful magnets and radio waves to image the location of hydrogen atoms in the body
• distinguishes body tissue based on water content
• low water content = not very visible
• high contrast images of soft tissue
• used for = imaging the brain, spinal cord, and nerves to detect abnormalities like tumors, assessing joints, ligaments, and other soft tissue, tracking blood flow allows for visualization of activity in brain regions

Answer 5

Magnetic Resonance Imagery (MRI)

Question 6

• high-frequency sound waves that reflect (echo) off body tissue
• does not use x-rays (damaging and dangerous)
• can monitor movement in real-time (heart valve motion and blood flow)
• inexpensive
• easy to use
• used for = reproduction, diagnosing abdominopelvic disorders (gallbladder disease), detecting atherosclerosis (thickening and hardening of arterial wall), heart valve disorders
• not used for = air-filled structures (lungs), structures surrounded by bone (brain, spinal cord)
• cons = images tend to be lower resolution, although sharpness is being improved

Answer 6

Ultrasound Imaging