Contrast media & meds

Question 1

WHY DO WE NEED CONTRAST AGENTS?

Answer 1

To help to visualise structures that would otherwise be difficult to see because different tissue typres are very similar in appearance to those around then

Question 2

How does contrast work?

Answer 2

High atomic number so high x-ray attenuation

Question 3

POM
Ba
BaSO4
Ba Swallow c̄ SALT

BaE
CO2

Answer 3

Prescription Only Medication 
Barium
Barium Sulphate
Barium Swallow examination with a Speech and Language Therapist present
Barium Enema
Carbon Dioxide

Question 4

What kinds of contrast are there

Answer 4

Suspension = doesn’t dissolve in water (barium) GI tract

Water soluble = gastrografin GI tract

Iodinated = contain iodine high atomic number and leaves the body Vascular system

Gases = Double-contrast or on its own GI tract

Radiopharmaceuticals = isotopes (RNI) Vascular system

Gadolinium = Vascular system (MRI)

Question 5

What are the categories of contrast?

Answer 5

Positive =
Radiopaque
High atomic number
e.g barium and iodine

Negative =
Radiolucent
Low atomic number
e.g CO2

Question 6

HOW IS CONTRAST ADMINISTERED?

Answer 6

Oral
Rectal
Intravenous (veins)
Natural Openings eg Sialograms or Dacrocystograms
Via a Fistula 
Via a Sinus

Question 7

What questions do we ask the patient?

Answer 7

Asthma / hayfever
Kidney problems
Heart problems / medication
Diabetes
Allergies
Possibility of Pregnancy
Have you had this procedure before?

Question 8

Types of Reaction

Answer 8

Transient- Self Limiting, do not interfere with examination
Vasovagal (Fainting) – Require some intervention
Mild – Does not interfere with the examination, but may progress
Intermediate – Interferes with examination, requires medical intervention
Severe – Respiratory or Cardiac Arrest

Question 9

Barium Sulphate Contra-Indications

Answer 9

Recent Surgery
Suspected Perforation
Incompetent Swallow
Biopsy with 7/7

Question 10

Water Soluble Contrast Contra-Indications

Answer 10

Recent Surgery
Pulmonary Oedema (if aspirated)
Hypovolaemia in children
Ileus

Question 11

Iodinated Contrast Contra-Indications

Answer 11

Previous Allergic Reaction
eGFR less than 30
Renal Failure

Question 12

Gadolinium Contra-Indications

Answer 12

Previous Allergic Reaction

Previous or Pre existing Nephrogenic Systemic Fibrosis (NSF)

Question 13

Gases Contra-Indications

Answer 13

No contra-indications

Except cant be used in veins

Question 14

Radiopharmaceuticals Contra-Indications

Answer 14

1. Recent chemotherapy
2. Recent radiotherapy
3. Poorly controlled diabetes

Question 15

Buscopan Contra-Indications

and what is it used for

Answer 15

Cardiac disease
Myasthenia Gravis (muscle weakness)
Mechanical Stenosis (blockage in GI)
Megacolon
It is employed to freeze bowel motion as part of many fluoroscopic, CT, and MRI studies

Question 16

Glucagon Contra-Indications

And what is it used for?

Answer 16

Diabetes
Insulinoma (tumor of pancreas)
Pheochromocytoma (tumor of the adrenal gland)

Glucagon is used during an MRI to slow down the motion in the bowels