Week 3

Question 1

Imaging modality characteristics:

Answer 1

• spatial: size of smallest structures that can be distinguished
• contrast: the ability to distinguish between intrinsic characteristics of different normal and abnormal structures
• temporal: the ability to deal with moving tissues and flowing blood
• radiation type and other hazards
• cost: 0-150 inexpensive; 150-400 medium; 400-up expensive
• availability/distribution

Question 2

Xrays

Answer 2

• PA and Lateral views
  - put front of chest against detector
  - put side of chest on detector
• Portable: used in hospitals; ER and NICU
  - cannot move the patient
  - pictures are not as clear
• Spatial: high, on well crafted xray machine
• Contrast: low; ~5 gray levels
• Temporal: low; blurry image with movement
• Radiation: xray; low
• Cost: low;
• Availability: easy to find

Question 3

Mammography Unit

Answer 3

• Spatial: High
• Contrast: Low
• Temporal: Low
• Radiation: x-ray; low
• Cost: low for screening
• Availability: medium

Question 4

Fluoroscopy

Answer 4

• Video x-ray
• Spatial: medium
• Contrast: low; even worse than regular x-ray
• Temporal: high
• Radiation: x-ray; depends on procedure-and amount of time it takes to finish
• Cost: medium/high; depends on procedure
• Availability: medium; in most hospitals but not in clinic
• fistulagram

Question 5

CT (Computed Tomography)

Answer 5

• Spatial: high
• Contrast: high; can increase by adding contrast-double edged sword, must be careful
• Temporal: low; exception of coronary CTA, using gating can freeze heart to allow you to take pic of heart in different stages
• Radiation: x-ray; high-the better the pic the more radiation
• Cost: high
• Availability: easy; in most hospitals, out patient m

Question 6

Ultrasound

Answer 6

• Spatial: Medium/High; have high and low resolution which depends on size of patient and structure trying to be seen
• Contrast: Low
• Temporal: High
• Radiation: non-ionizing soundwaves; Low
• Cost: Medium; depending on where it is done
• Availability: High; in clinics, hospitals

Question 7

MRI (Magnetic Imaging):

Answer 7

• Spatial: Medium/High; not as good as CT
• Contrast: High; can use contrast agents
• Temporal: Low/Medium; gated studies freeze motion of heart
• Radiation: Non-ionizing, radio waves and shifting magnetic fields; low
• Cost: High
• Availability: Medium; Hospitals

Question 8

Nuclear Medicine

Answer 8

• Spatial: Low
• Contrast: Low
• Temporal: Low; cardiac gating
• Radiation: Gamma radiation; high
• Cost: High
• Availability: Medium; Hospitals, few out patient

Question 9

PET

Answer 9

• Spatial: Low/High; combination of CT and specialized NM using positron emission
• Contrast: Low/High;
• Temporal: Low
• Radiation: X-ray and positron
• Cost: High
• Availability: Medium; Hospitals, cancer centers

Question 10

DEXA: Dual Energy X-ray Absorptiometry

Answer 10

• Spatial: NR
• Contrast: NR
• Temporal: Low
• Radiation: X-ray; low dose
• Cost: Low/Medium
• Availability: Easy to find