Salivary Gland Imaging
INTRODUCTION
Many different imaging modalities are useful in evaluation of salivary glands. In some
instances, one imaging technique is clearly preferable but in a number of situations the
information can be gathered using one or more approaches. The 2 most important clinical entities
to be imaged are palpable masses and recurrent swelling.
Salivary gland anatomy & physiology
These are paired glands that secrete a highly modified fluid through a branching duct
system.
Parotid saliva is released through Stenson’s duct, the orifice of which is visible on the
buccal mucosa adjacent to the maxillary first molars.
, The orifice of the submandibular duct - the Wharton’s duct is located sublingually on
either side of the lingual frenum. Sublingual saliva enters the floor of the mouth via the
Bartholin’s duct.
There are also thousands of minor salivary glands throughout the mouth, most of which are
named for their anatomic location as labial, buccal palatal etc.
The glands are composed of acinar & ductal cells. The acinar cells of parotid are serous,
those of sublingual, mucous & submandibular, mixed type.
Saliva is a highly complex mixture of water & various organic & non - organic
components.
It has a multitude of functions - lubrication, cleansing, physical protection, buffering
action & antibacterial.
The secretion of saliva is controlled by sympathetic & parasympathetic neural input.
Applied diagnostic imaging of salivary glands
Differentiate inflammatory processes from neoplastic disease.
Distinguish diffuse disease from focal suppurative disease.
Identify & localize sialoliths.
Demonstrate ductal morphology.
Determine anatomic location of tumour.
Differentiate benign from malignant disease
, Demonstrate the relationship between a mass & adjacent anatomic structures.
Aid in the selection of biopsy sites.
Imaging modalities
Plain films
Sialography
Computed tomography ( CT )
Magnetic Resonance Imaging ( MRI )
Ultrasound
Radionuclide salivary study
Sialoendoscopy
Overall imaging approach
Plain film radiography is typically the appropriate starting point for imaging of the major
salivary glands from a cost benefit point of view.
It can demonstrate sialoliths & possible involvement of adjacent osseous structures.
Sialography remains the only imaging study for examining the fine anatomy of the
salivary ductal system.
CT or ultrasound is the current standard for investigation of soft-tissue calcifications.
, CT has about a 10 fold increased sensitivity compared to plain films for detecting soft-
tissue calcifications & one of the primary strengths of ultrasound is its ability to identify
small, solid soft-tissue densities.
MR imaging is the primay modality of choice when a mass is palpated as it best
delineates the morphology of the mass.
Functional disorders such as xerostomia are appropriately imaged with sialography or
scintigraphy.
Nuclear medicine has specific applications. A Tc-99m pertechnate scan shows high
radionuclide uptake in Warthin’s tumour & oncocytoma.
Plain film radiography
It is the fundamental part of the examination of salivary glands & may provide sufficient
information to preclude the use of more sophisticated & expensive techniques.
Plain film radiographs are useful when the clinical impression, supported by a compatible
history, suggests the presence of sialoliths.
Such an examination should include both intraoral & extraoral images to demonstrate the
entire region of the gland.
It is expedient to use about half the usual exposure to avoid overexposure of the
sialoliths.
Parotid gland
Intraoral view - Periapical film
INTRODUCTION
Many different imaging modalities are useful in evaluation of salivary glands. In some
instances, one imaging technique is clearly preferable but in a number of situations the
information can be gathered using one or more approaches. The 2 most important clinical entities
to be imaged are palpable masses and recurrent swelling.
Salivary gland anatomy & physiology
These are paired glands that secrete a highly modified fluid through a branching duct
system.
Parotid saliva is released through Stenson’s duct, the orifice of which is visible on the
buccal mucosa adjacent to the maxillary first molars.
, The orifice of the submandibular duct - the Wharton’s duct is located sublingually on
either side of the lingual frenum. Sublingual saliva enters the floor of the mouth via the
Bartholin’s duct.
There are also thousands of minor salivary glands throughout the mouth, most of which are
named for their anatomic location as labial, buccal palatal etc.
The glands are composed of acinar & ductal cells. The acinar cells of parotid are serous,
those of sublingual, mucous & submandibular, mixed type.
Saliva is a highly complex mixture of water & various organic & non - organic
components.
It has a multitude of functions - lubrication, cleansing, physical protection, buffering
action & antibacterial.
The secretion of saliva is controlled by sympathetic & parasympathetic neural input.
Applied diagnostic imaging of salivary glands
Differentiate inflammatory processes from neoplastic disease.
Distinguish diffuse disease from focal suppurative disease.
Identify & localize sialoliths.
Demonstrate ductal morphology.
Determine anatomic location of tumour.
Differentiate benign from malignant disease
, Demonstrate the relationship between a mass & adjacent anatomic structures.
Aid in the selection of biopsy sites.
Imaging modalities
Plain films
Sialography
Computed tomography ( CT )
Magnetic Resonance Imaging ( MRI )
Ultrasound
Radionuclide salivary study
Sialoendoscopy
Overall imaging approach
Plain film radiography is typically the appropriate starting point for imaging of the major
salivary glands from a cost benefit point of view.
It can demonstrate sialoliths & possible involvement of adjacent osseous structures.
Sialography remains the only imaging study for examining the fine anatomy of the
salivary ductal system.
CT or ultrasound is the current standard for investigation of soft-tissue calcifications.
, CT has about a 10 fold increased sensitivity compared to plain films for detecting soft-
tissue calcifications & one of the primary strengths of ultrasound is its ability to identify
small, solid soft-tissue densities.
MR imaging is the primay modality of choice when a mass is palpated as it best
delineates the morphology of the mass.
Functional disorders such as xerostomia are appropriately imaged with sialography or
scintigraphy.
Nuclear medicine has specific applications. A Tc-99m pertechnate scan shows high
radionuclide uptake in Warthin’s tumour & oncocytoma.
Plain film radiography
It is the fundamental part of the examination of salivary glands & may provide sufficient
information to preclude the use of more sophisticated & expensive techniques.
Plain film radiographs are useful when the clinical impression, supported by a compatible
history, suggests the presence of sialoliths.
Such an examination should include both intraoral & extraoral images to demonstrate the
entire region of the gland.
It is expedient to use about half the usual exposure to avoid overexposure of the
sialoliths.
Parotid gland
Intraoral view - Periapical film
