Contrast Media

Question 1

Why is contrast media used?

Answer 1

-to visualise soft tissues

Question 2

How does contrast media work?

Answer 2

-reduced affect so x-ray beam hits soft tissues differently

-addresses the lack of contrast by selectively absorbing more x-ray photons than the soft tissues

Question 3

Where is contrast media absorbed?

Answer 3

-into the body to increase the contrast or structures of liquids

Question 4

How does contrast media exit the body?

Answer 4

Excreted from the body

Question 5

Where can contrast media be introduced into?

Answer 5

Blood vessels

Visceral

Cavities

Joints

Question 6

What is negative contrast media?

Answer 6

-has a very low physical density

-radiolucennt (appears black)

-used to define location of viscus rather than anatomical detail

Question 7

What are examples of negative contrast media?

Answer 7

Room air

Carbon dioxide

Oxygen

Question 8

What is positive contrast media?

Answer 8

-high atomic number and attenuate the x-ray beam more with viscus, organs and vacates

-radipaque (appears whiter than bone)

Question 9

What are examples of positive contrast media?

Answer 9

Barium

Iodine

Question 10

When is barium used?

Answer 10

Only for gastrointestinal studies

Question 11

What are advantages of using barium?

Answer 11

Insoluble

Inert (moves slowly)

Has therapeutic effects

Question 12

What are disadvantages of using barium?

Answer 12

May cause foreign body reaction if leaks

Constipation

Question 13

What are the different ways of giving barium, and when each is used?

Answer 13

Suspension - swallowing and oesophageal cases or GI tract

Paste - pharyngeal and oesophagus

Powders - not commonly used due to them building up

Question 14

When is iodine used as a contrast media?

Answer 14

Intravascular studies (GI tract)

Lower urinary tract studies

Joints

Salivary glands

Lacrimal sac and ducts

Question 15

What are advantages of using iodine?

Answer 15

Water soluble

Excreted by the kidneys

Question 16

What are disadvantages of using iodine?

Answer 16

Difficult to administer as is not palatable

Can cause fall in blood pressure

Cannot be used when conscious

Shows poor contrast for bowel

Question 17

How should ionic iodine contrast be given?

Answer 17

Should be warmed to body temp prior to use

Is viscous

Question 18

When should ionic iodine contrast be used?

Answer 18

Cardiovascular

Urinary tract

Question 19

Why is non-ionic iodine contrast used?

Answer 19

Less allergic reactions

More expensive

Shaper contrast bordered for an increased time

Question 20

What are the 5 methods of contrast radiography?

Answer 20

Gastrogram

Myelography

Retrograde urethrography

IV urography

Cystogram

Question 21

What does myelography indicate?

Answer 21

Lesions that are not detectable on ordinary x-ray

Question 22

When is myelography used?

Answer 22

Spinal pain

Neurological signs

Prolapsed invertebrate discs

Question 23

What are methods of myelography?

Answer 23

Cisterns magna puncture

Lumbar puncture

**GA is essential

Question 24

What contrast media is used for upper gastrointestinal study and how is it administered?

Answer 24

Barium sulphate

Orally administered using a stomach tube

Question 25

What patient preparation is required for upper gastrointestinal studies?

Answer 25

Fast for 12-24 hours Cleansing enema 24hrs prior before and 3 and 1 hr before X-rays taken 1hr after procedure

Question 26

What radiographs are taken for upper gastric study and when are they taken?

Answer 26

Dorso-ventral Right lateral Left lateral Immediately after administration Taken at 15, 30, 60, 90 mins intervals

Question 27

What contrast media is used for double cystography?

Answer 27

Air or gas Water soluble ionic or non-ionic agents

Question 28

What patient prep is required for double cystography?

Answer 28

Fasted 12-24hrs Enema at least 4hrs prior to exam m Abdominal images taken prior to sedation

Question 29

What contrast media is used for pneumocystography?

Answer 29

Gas or air Such as carbon dioxide

Question 30

What special precautions are taken when administering contrast for pneumocystography?

Answer 30

Patient positioned in left lateral recumbency to administer gas to reduce the risk of an air embolism Palpate bladder whilst administering gas to prevent rupture

Question 31

What patient prep is required for pneumocystography?

Answer 31

Fast for 12-24 hrs Enema at least 4hrs prior to exam Abdominal images taken prior to sedation

Question 32

What is the procedure of a pneumocystography?

Answer 32

R lateral and VD views of abdomen Insert catheter and empty bladder Plain radiograph taken before contrast Administer 2% lidocaine into bladder Place in L lateral and administer gas Take views of bladder with contrast

Question 33

When is double contrast used?

Answer 33

On hollow organs such as stomach or bladder Both positive and negative contrast media is utilised Used on cystogram and gastrogram

Question 34

What equipment required for GI blockage?

Answer 34

Barium solution Stomach tube Syringe X-day machine Barium used as not absorbed too quickly

Question 35

What equipment required for GI perforation?

Answer 35

Iodine Stomach tube Syringe X-ray machine Iodine as will be absorbed quickly

Question 36

Should the air be removed after contrast media study?

Answer 36

Must be removed

Question 37

What equipment is required for double cystogram?

Answer 37

Sedation Iodine solution Air (oxygen) Catheter Lube Syringe