1. Radiology Course Contrast Agents
Ghione Emanuele
Prof. Fabrizio Calliada

2. CONTRAST AGENTS History Definition Types RADIO - Contrast Agents
08/03/13
CONTRAST AGENTS
History
Definition
Types
RADIO - Contrast Agents
MRI Contrast Agents
US Contrast Agents
Conclusion

3. HISTORY First contrast agent discovered: Barium solphate
Initially mistaken for philosopher stone
1919: Heuser C. – use of contrast agent (Potassium Iodide) in living human circulatory system
1929: Swick M. – intravenous urograms.
1988: FDA declared Gadolinuim safe for MRI
The birth of CA goes bak to the end of XIX century. All the compounds used were taken from chemistry studies and all efforts were to reduce their toxicity to safely inject them IV.

4. CONTRAST AGENTS History Definition Types RADIO - Contrast Agents
08/03/13
CONTRAST AGENTS
History
Definition
Types
RADIO - Contrast Agents
MRI Contrast Agents
US Contrast Agents
Conclusion

5. Definition Contrast Agents
Substances that help in better differentiation beetween adjacent tissues
Positive (Iodinated contrasts)
Increase visualization of a tissue
Negative (Gases)
Reduce visualization of a tissue

6. CONTRAST AGENTS History Definition Types RADIO - Contrast Agents
08/03/13
CONTRAST AGENTS
History
Definition
Types
RADIO - Contrast Agents
MRI Contrast Agents
US Contrast Agents
Conclusion

7. TYPES RADIO-contrast agents (CT, X-RAYS) MRI contrast agents
Iodine (IV)
Barium sulfate (GI)
MRI contrast agents
Paramagnetic (Gadolinium-based) (IV)
Superparamagnetic (USPIO, SPIO) (IV)
Others (GI)
US contrast agents (CEUS)
Microbubbles (IV)

8. RADIO-contrast agents (CT, X-RAYS): IODINE
Intra-venous: Iodine
High Atomic Number (Z= 53)
Per OS: Gastrografin (contains Iodine)

9. Contrast enhancement is critical
The informed consent for using contrast is mandatory BEFORE the examination

10. Iodinated contrast agents
ADVERSE REACTIONS
Chemotoxic reactions (2-7%)
Dose-dependent
Mainly NEFROTOXIC EFFECTS
Contrast Induced Nephropathy
RISK FACTORS:
CRF(GFR < 30 ml/min)
Dehydration
Cardiac Failure
Metformin
Ipertiroidism
Risk of Thyrotoxic storm

11. Iodinated contrast agents
ADVERSE REACTIONS
Anaphylactoid reactions (1-2%)
Dose-independent
Mild: nausea, vomiting, flushing, flushing dizzyness, urticaria, pruritus
Moderate: bronchospasm, dyspnea, chest pain, hypotension
Severe(1/10.000): laryngeal edema, CPA, arrythmias
Delayed (>1h)
RISK FACTORS:
Previous allergic reactions to Iodine
Drug requiring allergies

12. RADIO-contrast agents (CT, X-RAYS): Barium Sulfate
Exclusive use in GI imaging
High attenuation coefficiency
insoluble
ADVERSE REACTIONS
Chemical peritonitis(!)
CONTRAINDICATIONS
perforation suspected
severe GI obstruction

13. MRI CONTRAST AGENTS Contrast Media
08/03/13
MRI CONTRAST AGENTS
Contrast Media
Paramagnetic or superparamagnetic substance
Shorten relaxation times of surrounding protons
Useful in T1-w sequences A
Signal B TR
Time

14. MRI CONTRAST AGENTS Gadolinium:
08/03/13
MRI CONTRAST AGENTS
Gadolinium:
Toxic in its free state - chelated to DTPA(Pentetic acid)
Risks:
- Systemic Nephrogenic Fibrosis
Contraindicated when GFR<30ml/min
- Acute adverse reactions
Less frequent than with I-

15. CONTRAST AGENTS History Definition Types RADIO - Contrast Agents
08/03/13
CONTRAST AGENTS
History
Definition
Types
RADIO - Contrast Agents
MRI Contrast Agents
US Contrast Agents
Conclusion

16. (contrast enhanced ultrasound)
CEUS
(contrast enhanced ultrasound)
SonoVue ®
Gas-filled microbubbles that are administered intravenously to the systemic circulation Intravenously administered
Microbubble contrast agents for ultrasound are completely different from those used for either CT or MR scans
Advantages:
First, microbubbles for CEUS are purely intravascular, whereas CT or MR contrast agents can diffuse through the vascular endothelium into the interstitium
Microbubble contrast agents are non-toxic and most patients are totally unaware of their injection
CEUS is most effective when used for specific and well-designed indications in abdominal imaging. The major established application is for characterization of focal liver masses

17. CONCLUSION Contrast agents Useful, in some cases necessary
Low intrinsic contrast of the tissue
(ej cystography)
Vascularized lesions
(ej. HCC)
Vessel evaluation
(Angiography, Coronary catheterization, MRI)
Potentially harmful
Ask your radiology when in doubt

18. Thank you!!!