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Advantages of MRIAdvantages of MRI
• Higher resolution of tissues• No ionizing radiation• Multiplanar imaging
Disadvantages of MRIDisadvantages of MRI
• Long imaging time• Hazards with ferromagnetic metals
(pacemakers, vascular clips, etc)• Claustrophobia• Higher cost
Relative Brightness of Relative Brightness of TissuesTissuesFat WhiteMarrowBrainMuscle GrayBody FluidTMJ DiskCortical BoneAir Black
Nuclear MedicineNuclear Medicine
Nuclear MedicineNuclear Medicine
• Radioactive compounds• Target tissues• Radioactive agents pools in
the target tissues• Detected and imaged by
external detectors (gamma camera).
Nuclear MedicineNuclear 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
TechnetiumTechnetium
• 99mTcO4- - thyroid and salivary
gland scan • 99Tc phosphate - bone scan
• Is this an active disease?
Phases of Salivary Gland Phases of Salivary Gland ScanScan
• 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
Cephalometric Cephalometric RadiographyRadiography• Reproducible and standardized
views• For measurements and assess
growth• Fixed source to film distance – 60
inches• Cephalostats and earplugs help in
reproducible positions
Cephalometric Cephalometric Radiography Radiography
Contrast AgentsContrast Agents
Contrast AgentsContrast Agents
• Radiopaque materials• Water soluble• Fat soluble• 28 – 38% iodine
Phases of SialographyPhases of Sialography
• Ductal• Acinar• Evacuation
Indications of SialographyIndications of Sialography
• Acute swelling secondary to ductal obstruction
• Recurrent Inflammation• Palpable salivary gland mass• Autoimmune Sialadenitis
Contraindications of Contraindications of SialographySialography• Sensitivity to contrast agents• Acute Sialadenitis• Limited use in tumor diagnosis
Scintigraphy SialographyRadioactive 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
Contrast Studies: Contrast Studies: ArthrographyArthrography
ArthrographyArthrography
• Contrast media is introduced in joint spaces
• Upper vs. lower joint space• Viewed by Image Intensifier
Fluoroscopy• Video recording allows study of joint
movement
Contrast Material InjectionContrast Material Injection
Open PositionOpen Position
• Translation of condyle
• Reduction of disk