Overview of diagnostic imaging

Question 1

What do x-rays show?

Answer 1

Variations in physical density

Question 2

Physical basis - scintigraphy

Answer 2

Gamma rays

Question 3

Scitigiraphy shows

Answer 3

Metabolic activity (i.e. physiologic not structural)

Question 4

MRI - physical basis

Answer 4

Radiowaves

Question 5

MRI - shows ?

Answer 5

Magnetisation

Question 6

Ultrasound - physical basis?

Answer 6

High frequency sound

Question 7

Ultrasonogrpahy shows?

Answer 7

Echogenicity

Question 8

Uses - radiography - 3

Answer 8

Bone, pulmonary and abdominal gas

Question 9

Spectrum of white/black - xrays

Answer 9

Bone>soft tissue>fat>airway

Question 10

Define tomography

Answer 10

Making images that represent a section through the body

Question 11

Define scitigraphy

Answer 11

Making images representing the distribution of radioactivity injected into a patient (radiopharmaceutical injection into jugular). Carcinomas cause ‘hotspots’ of metabolic activity

Question 12

How do you make MRI images?

Answer 12

Applying pulsed magnetic energy to the patient and collecting radiowaves that are emitted between pulses.

Question 13

Uses - MRI in animals

Answer 13

Predominantly for neurological problems. Shows brain in much more detail than CT. Fat shows up as white.

Question 14

Define ultrasonograpy

Answer 14

Making images by firing pulses of high frequency sound into the body and collecting the returning echoes.

Question 15

Is the spleen or liver more hyperechoic?

Answer 15

spleen (more echoes return from spleen than liver).

Question 16

Appearance of urine on ultrasound?

Answer 16

Black (no echoes)

Question 17

Uses - ultrasonography

Answer 17

• visualise internal vessels and gall bladder of liver
• differentiate bladder, lumen, prostrate and urethra
• determine if peristalsis in GIT is normal

Question 18

Common indicated for imaging

Answer 18

Owener’s view of problem –>refine problem –> system affected –> structural lesion (location) –> investigation may involve imagine (investigation less likely to involve imaging if a dysfunction is suspected)

Question 19

Result of diagnostic imaging =?

Answer 19

Description of the gross morphological features of a condition. Sometimes these are characteristic of a specific disease. Often further tests (biopsy) are required for a definite diagnosis. Predominantly to aid diagnosis, may also be used to guide biopsy or facilitate treatment

Question 20

Appearance of a CT image

Answer 20

Reverse colours to radiography (bones = black, lungs = white)