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

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

4. Relative Brightness of Tissues FatWhite Marrow Brain MuscleGray Body Fluid TMJ Disk Cortical Bone AirBlack

7. Nuclear Medicine

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

9. 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

10. Technetium 99m TcO 4 - - thyroid and salivary gland scan 99 Tc phosphate - bone scan

11. Is this an active disease?

14. Phases of Salivary Gland Scan Flow phase: –Five to 10 mCi of 99m TcO 4 –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

15. 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

16. Cephalometric Radiography

17. Contrast Agents

18. Radiopaque materials Water soluble Fat soluble 28 – 38% iodine

19. Phases of Sialography Ductal Acinar Evacuation

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

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

23. Scintigraphy Sialography Radioactive materialRadiopaque 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

24. Contrast Studies: Arthrography

25. 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

26. Contrast Material Injection

27. Open Position Translation of condyle Reduction of disk