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