2. INTRODUCTION
• Contrast imaging is a method which is used to allow visualization of
structures that cannot be seen well under normal circumstances.
• Contrast material is a chemical substance which is introduced in
human body via enteral/parenteral route to visualize certain
structures not seen in plain radiography
3. • The basic principle is to alter the absorption of x-rays by specific
anatomic structures in relation to their surroundings.
5. Ideal requirements
• Safe
• Non – toxic
• Easily removed from the body
• Have any residual side effect
• Opacification
• Low surface tension
• Easy injectability
• Easy elimination
6. Various contrast media
1. Barium sulphate suspensions for investigating the gastrointestinal tract.
2. Iodine-based aqueous solutions used for all other investigations and divided into:
• – Ionic monomers, including:
* iothalmate (e.g. Conray)
* metrizoate (e.g. Isopaque)
* diatrizoate (e.g. Urografin)
• – Ionic dimers, including:
* ioxaglate (e.g. Hexabrix)
• – Non-ionic monomers, including:
* iopamidol (e.g. Niopam)
* iohexol (e.g. Omnipaque)
* iopromide (e.g. Ultravist)
3. Iodine-based oil solutions such as Lipiodol (iodized poppy seed oil) used for sialography
4. MR contrast agents (e.g. gadolinium, saliva[sialography])
7. CONTRAST STUDIES USED IN DENTISTRY
• Sialography
• Arthrography
• Barium swallow
• Angiography
• Computed tomography
• Magnetic resonance imaging
9. A- unenhanced CT , B – CT taken after introducing contrast
agent (iodine)
10. MRI of the brain highlighting vasculature with gadolinium
contrast
11. Conclusion
• Contrast imaging is effective and accurate.
• It is needed to obtain a differential change in the attenuation values
of normal and pathological tissues.
• It does involve exposure to more radiation.
• Hence, should be used in mandatory conditions.
