Intro to Diagnostic Imaging

Question 1

what color will dense objects be on the x-ray?

Answer 1

radio-opaque (white)

Question 2

what color will non dense objects be on the x-ray?

Answer 2

radio-lucent (black or transparent)

Question 3

the gray scale order (dark to light)

Answer 3

air, fat, water, muscle, bone, barium, lead

Question 4

Role of the PT in radiology

Answer 4

1) no formal role in the ordering of assessment
2) vital to appreciate implications of study findings

Question 5

why use diagnostic imaging?

Answer 5

• localize the anatomic problem
• identify the tissue involved
  -identify the nature of the tissue damage
• direct treatment

Question 6

what is x-ray

Answer 6

-form of electromagnetic radiation, ionizing
-made by accelerating electrons hitting a tungsten target
-quality if image depends on kVolts, mA and exposure time
-depends of differential absorption by different tissue

Question 7

what is the value of routine radiography

Answer 7

documenting bony defects

Question 8

what is the minimum amount of views that are required for x-raying

Answer 8

2 views are required and are perpendicular to one another.

Question 9

advantages of x-ray

Answer 9

• quick
  -inexpensive
  -ideal for boney changes

Question 10

x-ray disadvantages

Answer 10

• does not show soft tissue changes
  -radiation exposure

Question 11

what does CT stand for

Answer 11

computerized (axial) tomography

Question 12

what is the CT scan

Answer 12

-a moving x-ray
-provides detailed planar images by progressive visual “slices”

Question 13

advantages of CT

Answer 13

• cross sectional images
  -can enhance with contrast
  -better sensitivity than plain film x-ray
  -OK with metal
• Fast

Question 14

disadvantages of CT

Answer 14

-high radiation exposure
-less sensitive then MRI

Question 15

What does MRI stand for

Answer 15

Magnetic Resonance Imaging

Question 16

what is MRI best for

Answer 16

soft tissue contracts

Question 17

What does MRI do

Answer 17

-Applies a powerful magnetic field to the patient
-detects the rate of magnetization and demagnetization
-produces “slice” images, can be in any plane

Question 18

Advantages of MRI

Answer 18

• the gray scale does not apply and any structure can be highlighted
  -no radiation exposure involved
  -High sensitivity to slight tissue differences

Question 19

Disadvantages of MRI

Answer 19

-cost
-time lying still
-Limited tube size
-Cannot use metal
-can be too sensitive/ not specific
-not good for bone/ calcified tissue

Question 20

How does ultrasound work

Answer 20

• sends in 35 MHz range (transmitter)
  -picks up receiver and examines timing and amplitude of the reflections for each echo, examines frequency change for doppler
  -produces a 2-D image in real time, can be moving

Question 21

Advantages to Ultrasound

Answer 21

-Biologically harmless
-records and displays motion
-requires no contrast
-portable
-distinguishes solid from fluid

Question 22

Disadvantages to Ultrasound

Answer 22

-does not penetrate bone well
-does not go through air/ gas
-skill dependent

Question 23

what images well with ultrasound

Answer 23

-fetus
-children
-abnormal organs (gallstones, kidneys, pelvic organs/masses
-aorta: aortic aneurysms
-blood flow (with doppler)

Question 24

Bone scan (Skeletal Scintigraphy) is used to test the suspection of

Answer 24

-metastatic disease
-arthritis
-stress fracture
-osteomyelitis
-loosening of implants
-multiple trauma

Question 25

how does bone scan work?

Answer 25

• patient is given a rapidly decaying radioisotope into their veins
• takes 2-4 hours for radioactive substance to gravitate to areas of bone damage
• one radiation has settled camera is used to image the bones, dark spots indicate damage

Question 26

what is nuclear imaging

Answer 26

a invasive procedure that uses injected radioactive material and a PET scanner, CT scan or MRI

Question 27

what images well with nuclear imaging?

Answer 27

• Thyroid masses
  -Bone metastases from cancer
• lung circulation and ventilation
  -cancer
• xenon
  -cancer
  -Gi disease
  -Endocrines disease

Question 28

what to look for when reviewing medical records of imaging

Answer 28

• any abnormalities are reported
• do they correlate with clinical signs and symptoms?