Radiological contrast media its type and classifications, contrast media reaction type and its management in the radiology department,

1. Radiological contrast media
Presented by:- Yashawant kumar
yadav
Bsc.MIT 2nd year
NAMS (Bir Hospital)

2. Outline
•Definition
•Types of CM and its classification
•Possible risk factors that cause CMR
•Types of reaction
•Management of CMR

3. Definition
Radiological contrast media are (positive ) chemical substance
that is introduce in to the body to enhance the visualization of
anatomical structure .
The use of radiographic contrast agents dates almost from the
discovery of X-Rays.
In 1896 Becher opacified the gastrointestinal tract of the guinea
pig using lead subacetate.

4. Why?
• Contrast media needed because soft tissue has low density and atomic
number.
• The ability to distinguish between tissues of different x-ray attenuation
(image contrast) depends upon two types of interactions between
photons and matter.
Interaction/ absorption depends on :-
1. Thickness
2. Density
3. Atomic number

5. Types
On the basis of radiographic contrast it is of two type:-
1. Negative contrast media
2. Positive contrast media
Negative contrast media (radiolucent) :-
• This type of contrast media show negative effective radiographic contrast in
radiograph (Black).
• Negative contrast media has low atomic number as compare to anatomical
tissues.

6. Contd..
As a negative contrast media
following can be used :-
1. CARBON DIOXIDE
2. AIR
3. OXYGEN
4. NITROUS OXIDE

7. Positive contrast media
As a Positive CM followings are used :
• Barium sulphate BaSO4
• Oily CM (LIPIODOL) Poppyseed oil is
used to inject along with iodine and ester of
fatty acid
• Water soluble Iodinated CM (Hepatic
excretion and Renal excretion)

8. Barium sulphate BaSO4
• High atomic number Atomic number 56, 0.3-12 um size, pH
5.3
• Not soluble in water = suspension
• Used to coat the lining of organs
• Supplied in different thicknesses
• Used
–Esophogram, UGI, Small Bowel, Lower GI or BE

9. Contd..
contraindications
 perforations of GI tract
 proximal to an obstructed bowel
precautions
 adequate hydration post examination

10. Contd..

11. Preparation of BaSO4 suspension
1. Weight/volume suspension
• Number of grams of solute in 100 mL solution
• For a 3% solution…
• 3 g of solute in 100 mL solution
2. Weight /weight suspension
• Number of g of solute in 100 g solution
• For a 8% solution…
• 8 g of solute in 100 g solution

12. Iodinated contrast
• As iodine has a high atomic number, 53, compared to most tissues in
the body, the administration of iodinated material produces image
contrast due to differential photoelectric absorption.
• Iodine has a particular advantage as a contrast agent because the k-
shell binding energy (k-edge) is 33.2 keV, similar to the average energy
of x-rays used in diagnostic radiography .
• When the incident x-ray energy is closer to the k-edge of the atom it
encounters, photoelectric absorption is more likely to occur.

13. Properties of CM
• Water solubility,
• Chemical and thermal stability
• Biologically inert
• low viscosity
• Non-antigenic
• iso-osmolar as human serum,
• renal excretion, low cost
• Don’t impair physiological homeostasis.
• High LD50

14. Classification

15. Contd..
Most ideal contrast media: Iodixanol (visipaque) & Itrolan (Isovist)

16. Contd..

17. Tonicity
1. High osmolar (> 1400 mosm/kg)
2. Low osmolar (600-580-800 mosm/kg)
3. Iso osmolar (290-350 mosm/kg)
ionic non ionic

18. Contd..
• The osmolality of a particular contrast agent is determined by the
number of osmotically active particles formed when it is dissolved in
solution.
• Ionic agents dissociate into ions when dissolved in water and contain
an iodinated benzene ring.
• As a result, ionic agents have a higher osmolality than blood .
• Nonionic agents do not dissociate into separate particles when dissolved
in water ; their osmolality is therefore one half that of ionic agents.
• Contrast agents with higher osmolality are more likely than those with
lower osmolality to cause adverse reactions of all types.

19. Structure
Ionic – monomer and dimer
Non ionic- monomer and dimer
• These are sodium or methylglucamine salts of 2,4,6 tri-iodobenzoic acid:
• Positions 3,5 are substituted with side chains which increase solubility and
decrease toxicity.

20. Contd..

21. Contd..
Tri-iodinated benzene ring
• C1 attachment differentiates ionic from non-ionic
•C1: Ionic (Acidic group with Sodium or meglumine) &
Nonionic (Amide group)
• Iodine atoms: C 2,4,6 positions and C3 and C5 have amide
attachments to increase solubility and reduce the protein
binding.
• Atomic weight provides excellent radio-opacity because of
high atomic number (53) and B.E of K-shell electron (34.2
KeV) closed to mean energy used in diagnostic X-ray and
maximize the photoelectric effect.

22. Contd..

23. Routs of contrast administration
• Contrast materials enter the body in one of three ways.
1. They can be: swallowed (taken by mouth or orally)
2. administered by enema (given rectally)
3. injected into a blood vessel (vein or artery; also called given
intravenously or intra-arterially)
4. Subdural sometimes
5. Percutaneous

24. Possible risk factors for Reaction
Acute reaction:-
1. Patients with a history of: Asthma
2. Prior reaction to contrast
3. Atopy Greater risk with ionic monomers.
Delayed reaction:-
1. Patients with a history of: Prior reaction to contrast
2. Those being treated with interleukin2
3. Greatest risk with non ionic dimers
4. Risk may be increased with sun exposure.

25. Contd..
Contrast Induce Nephropathy:-
• Preexisting renal dysfunction
• Dehydration
• Increased age
• Diabetes mellitus
• Hypertension
• Poor renal perfusion
• Congestive heart failure
• Myocardial infarction
• Hemodynamic instability
• Concurrent use of reno toxic drugs
• Aminoglycosides
• ACE inhibitors
• Use of a high-osmolality contrast agent High volumes of contrast agent

26. Categorization of contrast reaction
1. Idiosyncratic reaction (ON the basis of severity) independent of the
dose.(anaphylactoid )
• Mild ,Moderate & Severe
2. Non idiosyncratic reaction (non anaphylactoid ) (dose dependent ) organ
specific
I. Chemo toxic –
A. Nephrotoxicity
B. Cardio vascular toxicity
C. Neurotoxicity
II. Vasovagal
III. Idiopathic

27. Mild
Signs and symptoms appear self-limited without evidence of
progression
• Nausea, Cough, Warmth (heat)
• Headache, Dizziness Shaking
• Vomiting, Itching Rash Pallor Flushing Chills
• Altered taste , Sweats , hives
• Nasal stuffiness
• Swelling: eyes, face Anxiety
Treatment: Observation and reassurance. Usually no intervention or medication is
required; However, these reactions may progress into a more severe category.

28. Moderate
Reactions which require treatment but are not immediately life
threatening.
• Tachycardia/bradycardia ,Hypertension , cutaneous Reaction
• Hypotension ,Dyspnoea, Pulmonary edema
• Bronchospasm, wheezing ,Laryngeal edema
Treatment: Prompt treatment with close observation

29. Severe
Life threatening with more severe signs and symptoms.
• Laryngeal edema (severe or progressive)
• Clinically manifest
• Arrhythmias
• Convulsions
• Unresponsiveness
• Cardiopulmonary arrest
Treatment : Immediate treatment. Usually requires hospitalization

30. Delayed Contrast Reactions
• Delayed contrast reactions can occur anywhere from 3 hours to 7 days
following the administration of contrast.
• With the exception of contrast-induced nephropathy, the more common
reactions include a cutaneous exanthem, pruritis without urticaria,
nausea, vomiting, drowsiness (feeling sleepy), and headache.
• Delayed cutaneous reactions are more common in patients who have
had a previous contrast reaction are currently being treated with
interleukin-2 (IL-2).
• It is possible that these delayed reactions are T-cell mediated.

31. Anaphylactic and anaphylactoid
• Anaphylactic reactions are events
initiated when an allergen and IgE
combine to induce mast cells to
release chemical mediators.
• Histamine binds to specific
receptor sites.
• H1 receptors are found in
endothelial and smooth muscle
cells and in the central nervous
system.
• H2 receptors are in gastric
parietal cells and in inflammatory
cells.

32. Contd..
•The nature of an anaphylactic reaction depends upon the
location where it occurs.
 In the skin, vasodilatation produces urticaria and erythema
 In mucosa, vasodilatation produces nasal congestion and laryngeal edema.
In the respiratory tract, smooth muscle contraction produces bronchospasm.
 In peripheral vessels, vasodilatation produces hypotension and shock.
 Gastrointestinal reactions include nausea, vomiting, diarrhea, and cramps.

33. Anaphylactoid reactions
• Identical to anaphylactic reactions in their manifestations, but they are
not initiated by an allergen-IgE complex.
• The distinction between anaphylactic and anaphylactoid reactions is
subtle, but it has certain important implications for the use of iodinated
contrast:
1. A reaction can occur even the first time contrast is administered.
2. The severity of a reaction is not dose-related; therefore a test dose is of no value.
3. The occurrence of a contrast reaction does not necessarily mean that it will occur
again (although the risk is greater that it may).
4. Even though the circulating contrast is systemic, the nature of the response is
variable. More than one type of reaction may occur simultaneously.

34. Management of Anaphylactoid Rxn

35. NEPHROTOXICITY
• The kidneys receive 20–25 percent of resting cardiac output,
approximately 1.2– 1.3 liters every minute.
• Glomerular filtration rate is about 125 mL/min, or 180 liters per day.
• Iodinated contrast agents have a molecular weight in the range of 600–
1650 g/mol.
Pathogenesis:-
 Three general types of mechanisms have been described.
1. Vascular changes.
2. Tubular injury. Clearance of (para-aminohippurate) derivative of hippuric acid (rise in the
urinary excretion of enzymes found in proximal tubular cells. )
3. Tubular obstruction. (PPT of Bence-Jones proteins) (multiple myeloma )

36. Diagnosis
• A serum creatinine of greater than 1.5 mg/dL indicates renal insufficiency.
• The glomerular filtration rate (GFR) must decline by about 50 percent, to 60
mL/min,
• With respect to GFR, moderately decreased renal function is defined as GFR 30-
59, severely decreased renal function is defined as GFR 15-29 and renal failure is
defined as GFR<15.

37. Contd..
• In general acute renal failure is defined when the serum creatinine raises 25–50
percent or 0.5–1 mg/dL.
• Serum creatinine peaks in 3–5 days but may be elevated as early as the first day
• Clinical manifestations are highly variable and may be absent or proceed to
oliguria (urine output < 400 mL/24h).
• Most effects are temporary and completely reversible. In mild cases, serum
creatinine returns to normal in 2 weeks.
• When severe, dialysis may be necessary.

38. Predisposing Factors
• RENAL IMPAIRMENT
• DIABETES
• METFORMIN (GLUCOPHAGE™) is an oral antihyperglycemic medication used
to treat diabetes.
• Therefore, it is important to obtain a list of ALL of the oral medications a patient
uses to treat his or her diabetes and to search for metformin or metformin-
containing formulations.

39. Contd..
• Lactic acidosis can be fatal. Conditions that reduce metformin excretion or
increase serum lactate include:
1. Renal disease–decreases metformin excretion
2. Liver disease–decreases lactic acid metabolism
3. Heart disease–increases anaerobic metabolism

40. CARDIOVASCULAR TOXICITY
• Patients with underlying cardiac disease have an increased incidence
and/or severity of cardiovascular side effects.
• Possible reactions include hypotension, tachycardia, and arrhythmias.
• More severe, but uncommon reactions include congestive heart failure,
pulmonary edema, and cardiac arrest.

41. NEUROTOXICITY
• Iodinated contrast agents cause a change in the blood-brain barrier due to their
hypertonicity.
• These risks are reduced when low or iso-osmolar agents are used.
• Potential reactions include headache, confusion, seizures, altered
consciousness, visual disturbances, and dizziness.

42. VASOVAGAL REACTIONS
•Vasovagal reactions are characterized by bradycardia and
hypotension.
 elevating the legs and/or placing the patient in a Trendelenburg position
administering oxygen at the rate of 6–10 liters/minute.
 Atropine may be used in the initial treatment of bradycardia
IV fluids are used to treat hypotension and should be administered rapidly
It is important to monitor vital signs frequently to titrate the amount of
medications and fluids that are used

43. EXTRAVASATION OF CONTRAST
• Extravasation of small amounts of contrast usually results in only minimal
symptoms, including swelling, erythema, and pain.
• These symptoms usually abate with no lasting effect.
• Depending on the agent used, severe reactions can occur.
• They take the form of skin ulceration and necrosis.

44. PREMEDICATION
• Overall, patients who are at increased risk for an anaphylactoid reaction
benefit from premedication. (13th to 7hr )
1. Methylprednisolone/predisone :
DOSE: 32-50 mg P/O 12 and 2 hours before contrast.
2. Diphenhydramine:
DOSE: a. 50 mg IM or PO 1 hour before contrast,
 OR b. 50 mg (or 25 mg per height/weight indication) IV 15–20 minutes before
contrast.
3. Hydrocortisone :- 50 mg IVly
In addition, these patients should receive nonionic contrast agents.

45. Medicines used in radiology in case of CR
1. Albuterol Inhaler:
 A Beta-2 agonist that causes bronchodilatation and relieves bronchospasm that
may occur with asthma or as a reaction to contrast
DOSE: 2 puffs to start ( May need to be repeated )
2. Atropine:
 A parasympatholytic agent used to treat bradycardia that results from a vasovagal
reaction (characterized by hypotension and bradycardia)
DOSE: 0.6–1.0 mg IV slowly Maximum dose = 2 mg

46. Contd..
3. Diphenhydramine:
An antihistamine which is an H-1 receptor site blocker. In this capacity, it blocks
circulating histamine from binding to target cells.
 Diphenhydramine should not be used for severe urticaria or other more
significant reactions
DOSE: 25–50 mg IV or IM
4. Clonidine:
 A drug used to treat a hypertensive crisis.
DOSE: 200 mcg (0.2 mg). Bite, chew, and swallow.

47. Contd..
5. Epinephrine:
 A drug which is a basic sympathetic agonist with the following effects:
As an alpha agonist, epinephrine is used to treat severe urticaria, facial edema,
and laryngeal edema.
As a beta-2 agonist, it may be needed to treat bronchospasm.
 Epinephrine is supplied in two strengths: 1:1,000 in 1 mL vials for subcutaneous
use, and 1:10,000 in 10 mL prefilled syringes for intravenous use.
DOSE: Subcutaneous: 1:1,000 (1 mg/mL) 0.1–0.3 mL (0.1 – 0.3 mg)
DOSE: Intravenous: 1:10,000 (0.1 mg/mL) 1 mL IV slowly every 3–5 minutes
May repeat up to 1 mg maximum

48. Contd..
6. Diazepam:
 A benzodiazepine used to treat seizures.
DOSE: 5–10 mg IV push Maximum dose: 30 mg
7. Nitroglycerin:
A vasodilator used to treat acute angina.
DOSE: 0.4 mg sublingual May be repeated q 5 minutes for a total of 3 doses

49. References
1. https://www.radiology.wisc.edu/wp-content/uploads/2017/10/contrast-
agents-tutorial.pdf
2. https://pdfs.semanticscholar.org/b481/98c04700871d9876f1b2ebc39871535a
9450.pdf
3. https://www.acr.org/-/media/ACR/files/clinical-resources/contrast_media.pdf
4. http://www.just.edu.jo/DIC/Manuals/Reactions%20to%20radiocontrast%20m
edia%20and%20its%20managment.pdf

50. THANK YOU

51. • How many grams of dextrose are required to prepare 4000 mL of a
5% solution?
(5% solution = 5 g of dextrose in 100 mL)
5 g = x g
100 mL 4000 mL
x = 200 g