1. Advantages of MRI Higher resolution of tissues No ionizing radiation
Multiplanar imaging

2. Disadvantages of MRI Long imaging time
Hazards with ferromagnetic metals (pacemakers, vascular clips, etc)
Claustrophobia
Higher cost

3. Relative Brightness of Tissues
Fat White
Marrow
Brain
Muscle Gray
Body Fluid
TMJ Disk
Cortical Bone
Air Black

6. Nuclear Medicine

7. Nuclear Medicine Radioactive compounds Target tissues
Radioactive agents pools in the target tissues
Detected and imaged by external detectors (gamma camera).

8. Nuclear Medicine Shows structure and function of the target tissues
Static and dynamic conditions
Scintigraphy scans or RN (radionuclide) scans
Bone scans or salivary gland scans

9. Technetium 99mTcO4- - thyroid and salivary gland scan
99Tc phosphate - bone scan

10. Is this an active disease?

13. Phases of Salivary Gland Scan
Flow phase:
Five to 10 mCi of 99mTcO4
first 30 to 120 seconds
shows flow of blood
Concentration phase:
next 30 to 45 minutes
demonstrate the anatomy and function
Washout Phase:
administer sialagogue
demonstrates secretory capabilities

14. Cephalometric Radiography
Reproducible and standardized views
For measurements and assess growth
Fixed source to film distance – 60 inches
Cephalostats and earplugs help in reproducible positions

15. Cephalometric Radiography

16. Contrast Agents

17. Contrast Agents Radiopaque materials Water soluble Fat soluble
28 – 38% iodine

18. Phases of Sialography
Ductal
Acinar
Evacuation

19. Indications of Sialography
Acute swelling secondary to ductal obstruction
Recurrent Inflammation
Palpable salivary gland mass
Autoimmune Sialadenitis

20. Contraindications of Sialography
Sensitivity to contrast agents
Acute Sialadenitis
Limited use in tumor diagnosis

22. Scintigraphy Sialography Radioactive material Radiopaque material
Through blood stream
Through duct
All glands imaged at the same time
One gland at a time
Imaged by gamma camera
Imaged by fluoroscopy

23. Contrast Studies: Arthrography

24. Arthrography Contrast media is introduced in joint spaces
Upper vs. lower joint space
Viewed by Image Intensifier Fluoroscopy
Video recording allows study of joint movement

25. Contrast Material Injection

26. Open Position
Translation of condyle
Reduction of disk