about contrast materials used in radiology

1. CONTRAST MEDIA
IN RADIOLOGY
SUPPAT ITTIMAKIN, MD.

2. CONTRAST MEDIA
• Substance used to enhance the contrast of the structures or fluid within the body
in medical imaging
• Types of contrast agent
- Iodinated contrast agent
- MR contrast agent: Gadolinium-based contrast agent
- Negative contrast agent  air

3. IODINATED CONTRAST MEDIA
• Radiopaque contrast agents are often used in radiography and fluoroscopy to
help delineate borders between tissues with similar radiodensity
• Types of iodinated contrast media
- Ionic
- Non-ionic

4. EFFECT OF
INTRAVENOUS
CONTRAST
INJECTION

5. CONTRAST MEDIA
Ionic contrast agents:
• Hyperosmolarity to blood
• Should not be used for myelography or in injections that may enter the spinal
canal (because neurotoxicity is a risk) or the bronchial tree (because pulmonary
edema is a risk)
• Incidence of irreversible renal failure in some medical condition such as
paraproteinemia in multiple myeloma

6. CONTRAST MEDIA
Nonionic contrast agents:
• Low-osmolar (but still hyperosmolar relative to blood ; 300 mg I/ml) or iso-
osmolar (with the same osmolarity as blood)
• Now routinely used  Fewer adverse effects

9. MR CONTRAST AGENT
• Extracellular contrast agent
• Organ specific agent
• Blood pool agent

10. GADOLINUM-BASED MR CONTRAST
• Improve visilbility of the internal body structures in MRI
• Shortening of the T1 relaxing time of the atom
• Do not pass blood brain barrier

12. NEGATIVE
CONTRAST
MEDIA
• Air: Use in double-
contrast fluoroscopy

13. CONTRAST
REACTION

14. GOAL OF CONTRAST USAGE
• 1) to assure that the administration of contrast is appropriate for the patient and
the indication
• 2) to minimize the likelihood of a contrast reaction
• 3) to be fully prepared to treat a reaction should one occur

15. ADVERSE EFFECT OF INTRAVENOUS
CONTRAST MEDIA
• Allergy
• Contrast-induced nephropathy
• Nephrogenic systemic fibrosis
• Contrast extravasation

16. ALLERGY

17. RISK FACTOR FOR INTRAVENOUS CONTRAST
REACTION
• Allergy
• Asthma
• Renal insufficiency
• Cardiac status
• Miscellaneous factors: Age, underlying disease such as hyperthyroidism,
paraproteinemia in multiple myeloma, sickle cell anemia, etc.

18. ALLERGY
• Allergic of prior contrast usage  increased 5 fold likelihood ratio
• Allergic rhinitis ??
• Seafood allergy ??
• History of anaphylaxis

19. ASTHMA
• A history of asthma may indicate an increased likelihood of a contrast reaction
• Especially active hyperresponsive airway disease

20. RENAL INSUFFICIENCY
• Can causes contrast-induced nephropathy (CIN), nephrogenic systemic fibrosis
(NSF)
• Metformin usage

21. CARDIAC DISEASE
• Congestive heart disease, severe aortic stenosis, pulmonary hypertension,
severe cardiomyopathy
• May increased risk of contrast reaction
• Attention should be paid to limiting the volume and osmolality of the contrast
media.

22. PREMEDICATION
• Approximately 90% of such adverse reactions are associated with direct release
of histamine and other mediators from circulating basophils and eosinophils
• Pathophysiologic explanations include activation of mast cells and basophils
releasing histamine, activation of the contact and complement systems,
conversion of L-arginine into nitric oxide, activation of the XII clotting system
leading to production of bradykinin, and development of “pseudoantigens”

23. PREMEDICATION
• Dose response studies in humans of the suppression of whole blood histamine
and basophil counts by IV methylprednisone show a reduction in circulating
basophils and eosinophils by the end of the first postinjection hour
• However, reaching statistical significance compared with controls by the end of
the second hour, and maximal statistical significance at the end of 4 hours

24. RECOMMENDED PREMEDICATION REGIMENS
Elective Premedication
Two frequently used regimens are:
First regimen:
• Prednisone – 50 mg by mouth at 13 hours, 7 hours, and 1 hour before contrast
media injection, plus
• Diphenhydramine (Benadryl®) – 50 mg intravenously, intramuscularly, or by
mouth 1 hour before contrast medium

25. RECOMMENDED PREMEDICATION REGIMENS
Second regimen:
• Methylprednisolone (Medrol®) – 32 mg by mouth 12 hours and 2 hours before
contrast media injection
• An anti-histamine (as in option 1) can also be added to this regimen injection
If the patient is unable to take oral medication, 200 mg of
hydrocortisone intravenously may be substituted for oral prednisone

26. RECOMMENDED PREMEDICATION REGIMENS
Emergency Premedication
(In Decreasing Order of Desirability)
• Methylprednisolone sodium succinate (Solu-Medrol®) 40 mg or hydrocortisone
sodium succinate (Solu-Cortef®) 200 mg intravenously every 4 hours (q4h) until
contrast study required plus diphenhydramine 50 mg IV 1 hour prior to contrast
injection

27. RECOMMENDED PREMEDICATION REGIMENS
• Dexamethasone sodium sulfate (Decadron®) 7.5 mg or betamethasone 6.0 mg
intravenously q4h until contrast study must be done in patent with known allergy
to methylpred-nisolone, aspirin, or non-steroidal anti-inflammatory drugs,
especially if asthmatic. Also diphenhydramine 50 mg IV 1 hour prior to contrast
injection.
• Note: IV steroids have not been shown to be effective when administered less
than 4 to 6 hours prior to contrast injection.

28. PREMEDICATION
Type of contrast agent
• Osmolarity: Hyperosmolality is associated with the stimulation of release of
histamine from basophils and mast cells
• Complexity and molecular size: Increase in the size and complexity of the
contrast molecule may potentiate the release of histamine
Nonionic monomers also produce lower levels of histamine release from basophils
compared with high-osmolality ionic monomers, low-osmolality ionic dimers and
iso-osmolality nonionic dimers

29. ACUTE CONTRAST REACTION
• Allergic-liked reaction : from histamine which is released by mast cell and
basophil
• Physiologic reaction : direct chemotoxicity, osmotoxicity (adverse effects due to
hyperosmolality) or molecular binding to certain activators
• Frequently dose and concentration dependent
• Frequent reaction: vagovagal reaction, feeling of apprehension and
accompanying diaphoresis
• Rare reaction: Cardiac arrhythmias, depressed myocardial contractility,
cardiogenic pulmonary edema, and seizures

30. DELAYED CONTRAST REACTION
• Most commonly cutaneous and may develop from 30 to 60 minutes to up to one
week following contrast material exposure
• Can occurring between three hours and two days
• Symptoms; allergic-liked cutaneous reaction (most common), nausea/vomitting,
fever, headache, iodine-related sialoadenopathy, polyarthroplasty

31. EVALUATION OF THE CONTRAST REACTION
Mild reaction
• Signs and symptoms are self-limited without evidence of progression. Mild
reactions include:
• Allergic-like : Limited urticaria / pruritis Limited cutaneous edema Limited “itchy” /
“scratchy” throat Nasal congestion/ Sneezing / conjunctivitis / rhinorrhea
• Physiologic : Limited nausea / vomiting/ Transient ushing / warmth / chills
Headache / dizziness / anxiety / altered taste Mild hypertension/ Vasovagal
reaction that resolves spontaneously

32. EVALUATION OF THE CONTRAST REACTION
Moderate
• Signs and symptoms are more pronounced and commonly require medical
management. Some of these reactions have the potential to become severe if not
treated. Moderate reactions include:
• Allergic-like
• Diffuse use urticaria / pruritis, Diffuse erythema, stable vital signs, Facial edema
without dyspnea, Throat tightness or hoarseness without dyspnea
• Wheezing / bronchospasm, mild or no hypoxia

33. EVALUATION OF THE CONTRAST REACTION
Moderate
• Physiologic
• Protracted nausea / vomiting Hypertensive urgency Isolated chest pain
• Vasovagal reaction that requires and is responsive to treatment

34. EVALUATION OF THE CONTRAST REACTION
Severe
• Allergic-like
• Diffuse edema, or facial edema with dyspnea Diffuse erythema with hypotension
Laryngeal edema with stridor and/or hypoxia, Wheezing / bronchospasm,
Significant hypoxia, Anaphylactic shock (hypotension + tachycardia)
• Physiologic
• Vasovagal reaction resistant to treatment Arrhythmia
Convulsions, seizures Hypertensive emergency

35. TREATMENT OF MILD REACTION
• Typically do not require medical treatment
• Vital signs should be obtained to detect hypotension that may be clinically silent
while the patient is supine
• Observed for 20 to 30 minutes, or as long as necessary
• Antihistamine IV

36. TREATMENT OF MODERATE TO SEVERE
REACTION
• IV fluid
• Antihistamine : Benadryl 1 mg/kg IV for moderate urticaria
• Epinephrine 0.1 mg/kg IV or 0.3 mg IM for profound hypotension, anaphylaxis,
bronchospasm
• Betaagonist inhalator for mild and moderate bronchospasm

37. CONTRAST-INDUCED
NEPHROPATHY (CIN)

38. CONTRAST-INDUCED NEPHROPATHY
• A sudden deterioration in renal function that is caused by the intravascular
administration of iodinated contrast medium
• Diagnosis by use percent change in the baseline serum creatinine and absolute
elevation from baseline serum creatinine (absolute increase of 0.5 mg/dL over a
baseline)

39. DEFINITION OF ACUTE RENAL INJURY
The diagnosis of AKI is made according to the AKIN criteria if one of the following
occurs within 48 hours after a nephrotoxic event (e.g., intravascular iodinated
contrast medium exposure):
• Absolute serum creatinine increase ≥0.3 mg/dL (>26.4 μmol/L)
• A percentage increase in serum creatinine ≥50% (≥1.5-fold above baseline)
• Urine output reduced to ≤0.5 mL/kg/hour for at least 6 hours.

40. RENAL FUNCTION
• Serum creatinine concentration is the most commonly used measure of renal
function
• BUT!!! Serum creatinine has limited accuracy for evaluate GFR
• Calculated estimated glomerular filtration rate (eGFR) is more accurate than is
serum creatinine at predicting true GFR
eGFR is gaining attention as a potentially better marker of CIN risk

41. RISK FACTORS
• Pre-existing severe renal insufficiency  Most important risk factor
• - eGFR < 30 ml/min/1.73 m2  significant risk
• Underlying disease: DM, Cardiovascular disease, Multiple myeloma,
Hypertension
• Dehydration
• Diuretic use
• Advanced age
• Multiple iodinated contrast medium doses in a short time interval (<24 hours)

42. PREVENTION
• Avoid usage of the iodinated-contrast agent
• Select type of contrast agent : LOCM are less nephrotoxic than HOCM in patients
with underlying renal insufficiency.
• Volume expansion : Major effective action
- 0.9% saline at 100 mL/hr, beginning 6 to 12 hours before and continuing 4 to 12
hours after intravenous iodinated contrast administration
• N-acetylcysteine : unknown mechanism

43. RENAL INSUFFICIENCY
• Most low-osmolality iodinated contrast media are not protein-bound, have
relatively low molecular weights, and are readily cleared by dialysis
• Unless an unusually large volume of contrast medium is administered, or there is
substantial underlying cardiac dysfunction, there is no need for urgent dialysis
after intravascular iodinated contrast medium administration

44. NEPHROGENIC
SYSTEMIC FIBROSIS
(NSF)

45. NEPHROGENIC SYSTEMIC FIBROSIS
• Fibrosing disease, primarily involving the skin and subcutaneous tissues
• but also involve other organs, such as the lungs, esophagus, heart, and skeletal
muscles
• Initial symptoms typically include skin thickening and/or pruritis
• May develop and progress rapidly, with some affected patients developing
contractures and joint immobility
• In some patients, the disease may be fatal

46. ASSOCIATION
• Gadolinium-based MR contrast
• Acute kidney injury (AKI)
• Chronic renal disease
Patients with end-stage CKD (CKD5, eGFR < 15 mL / min/1.73 m2) and
severe CKD (CKD4, eGFR 15 to 29 mL / min/1.73 m2) have a 1% to 7%
chance of developing NSF after one or more exposures to at least some
GBCAs

47. RECOMMENDATION
ACR Committee on Drugs and Contrast Media believes that patients receiving any
GBCA should be considered at risk of developing NSF if any of the following
conditions applies:
• on dialysis (of any form)
• severe or end-stage CKD (CKD 4 or 5, eGFR < 30 mL / min/1.73 m2) without
dialysis
• eGFR 30 to 40 mL / min/1.73 m2 without dialysis*
• AKI

48. NSF WITH HEMODIALYSIS
• Hemodialysis ???
• Most patients who developed NSF had end-stage kidney disease and were on
dialysis at the time of exposure
• So, hemodialysis cannot prevent NSF !!!

49. CONTRAST
EXTRAVASATION

50. CONTRAST EXTRAVASATION
• Leakage of the contrast agent from systemic circulation
• Incidence 0.1% - 0.9%
Sign and symptom:
• Complain of initial swelling or tightness, and/or stinging or burning pain at the site
of extravasation
• Edematous, erythematous, and tender nearby the injected site

53. RISK OF CONTRAST EXTRAVASATION
• Patients who cannot communicate adequately
• Severely ill or debilitated patients
• Patients with abnormal circulation in the limb to be injected :
• - Atherosclerotic peripheral vascular disease
• - Diabetic vascular disease, Raynaud’s disease, venous thrombosis or
insuffciency
• - Prior radiation therapy or extensive surgery

54. RISK OF CONTRAST EXTRAVASATION (CONT.)
• >24 hour of injected site
• Multiple venous punture
• High injected flow rate ???
• Amount of injected contrast agent ???

55. SEQUELAE OF CONTRAST EXTRAVASATION
• Acute local inflammatory response (24-48 hr)  due to hyperosmolarity of the
contrast media
• Hyperosmolar contrast agent can cause more severe reaction than low-osmolar
contrast agent
• Most extravasations are limited to the immediately adjacent soft tissues (typically
the skin and subcutaneous tissues), and usually there is no permanent injury

56. COMPLICATION OF THE CONTRAST
EXTRAVASTION
• Compartment syndrome  occur after large amount of contrast leakage
• Skin ulceration
• Soft tissue necrosis

58. TREATMENT OF CONTRAST EXTRAVASATION
• Elevation of the affected extremity above the level of the heart  decrease
capillary hydrostatic pressure and promote resorption of extravasated fluid
• Warm or cold compresses ???
• Aspirate the extravasated contrast medium through an inserted needle or
angiocatheter ???
• Local injection of other agents such as corticosteroids or hyaluronidase ???
• Surgical consult : progressive swelling or pain, altered tissue perfusion, change in
sensation in the affected limb, and skin ulceration or blistering

59. REFERENCES
• Introduction ACR Manual on Contrast Media – Version 10.1, 2015

60. THANK YOU FOR
YOUR ATTENTION