Salivary glands — Reference values

Salivary glands — Reference values: Minimum protocol, Parotid — approximate cut-surface area, Submandibular — approximate cut-surface area, Main salivary duct.

Brazil and other regions: parotid, submandibular and sublingual glands should be assessed as a dedicated examination when requested. Ultrasound is strong for superficial parenchyma, stones, dilated duct, collection, lymph nodes and guided sampling; it is limited for the deep parotid lobe, perineural spread, skull base and deep staging, where computed tomography or magnetic resonance may be needed.

Measurements and reference values

Measurement	Usual value	Note
Minimum protocol	high-frequency linear transducer; transverse, longitudinal and anteroposterior planes; bilateral comparison; color/power Doppler in lesions	Assess parenchyma, echogenicity, ducts, stone, collection, mass, cervical lymph nodes and relationship with skin, masseter, mandible, oral floor and vessels. Every focal lesion should be measured in three axes.Source: ACR-AIUM-SPR-SRU Head and Neck 2022 / AIUM Head and Neck
Parotid — approximate cut-surface area	≈ 3–4 cm²	Teaching value, not universal. Comparison with the opposite side, atrophy, post-treatment change, inflammation and body habitus matter more than an isolated cutoff.teaching range: 3–4 cm²contextual: outside range or asymmetrySource: Iowa Head and Neck Protocols
Submandibular — approximate cut-surface area	≈ 1–2 cm²	Teaching value. A small/atrophic gland may occur with age, chronic obstruction, Sjögren, radioiodine or radiation therapy; enlargement may be inflammatory/obstructive.teaching range: 1–2 cm²contextual: outside range or asymmetrySource: Iowa Head and Neck Protocols
Main salivary duct	normally not visible	A visible, dilated duct or transition point suggests obstruction/stenosis when associated with meal-related pain, stone, gland swelling or purulent secretion.usual: duct not visible and no obstructive symptomsgray zone: isolated visible duct or suspected stenosis without stoneabnormal: dilated duct with stone, meal pain, pus or collectionSource: Iowa Head and Neck Protocols / AIUM Head and Neck
Sialolithiasis	intraductal echogenic focus with shadow/twinkle + proximal dilatation	Ultrasound sensitivity varies with stone size/location and ductal dilatation; a small stone without a dilated duct can be false negative. Calcification outside the duct may be a calcified node, phlebolith or vascular calcification.suspicious: calcification without clear ductal continuityconsensus abnormal: intraductal stone with shadow/twinkle and dilated ductSource: AJR 2013 / PMC salivary calculi review / Radiopaedia
Focal salivary lesion	measure three axes + Doppler + lymph nodes	Size alone does not define benignity. Irregularity, infiltration, extraglandular extension, facial palsy, suspicious nodes, rapid growth or progressive pain increase risk.indeterminate: solid/cystic mass without aggressive signshigh risk: infiltrative margins, extension, facial nerve or suspicious nodesSource: ACR-AIUM-SPR-SRU Head and Neck / salivary tumor imaging reviews

Classifications and calculators

Interactive assistant — salivary glands

Source: ACR-AIUM-SPR-SRU Head and Neck / Iowa / OMERACT / AJR

Sjögren — OMERACT 0-3 per gland

Grade	Finding	Teaching color
0	Normal/homogeneous parenchyma	Green
1	Mild inhomogeneity without defined hypoechoic/anechoic areas	Yellow
2	Moderate change with focal hypoechoic/anechoic areas surrounded by preserved parenchyma	Yellow/Red by context
3	Severe change: diffuse hypo/anechoic areas involving the gland, fibrosis or fatty replacement	Red when concordant with clinical/serologic context

OMERACT is a structural per-gland scale. Recent studies explore 0-12 sum and 0-6 ordinal scores; high thresholds have higher specificity, but ultrasound does not replace clinical criteria, serology, sialometry or biopsy when needed.

Source: OMERACT / RMD Open 2021 / Arthritis Res Ther 2026

Salivary obstruction — color reading

Finding	Green	Yellow	Red
Duct	not visible	isolated visibility or salivary stimulation changes caliber	dilated with transition point, stone, pus or collection
Stone	absent	calcification without clear ductal continuity	intraductal focus with shadow/twinkle and proximal dilatation
Infection	no hyperemia/collection	painful/hypervascular gland without collection	abscess, gas, cellulitis, fever or purulent secretion

Absence of a stone on ultrasound does not exclude treatable duct stenosis; duct dilatation has high predictive value for stenosis in sialendoscopy series.

Source: Iowa Head and Neck Protocols / AJR 2013

Salivary mass — differential and risk signs

Pattern	Useful differentials	What changes priority
Well-defined solid	pleomorphic adenoma, Warthin tumor, intraparotid lymph node, oncocytoma	measure 3 axes, Doppler and nodes; sampling according to local protocol
Cystic	ranula, sialocele, lymphoepithelial cyst, cystic node, abscess, cystic tumor	complex content, hyperemia, gas or fever increase urgency
Infiltrative/aggressive	primary malignancy, metastasis, lymphoma, carcinoma ex pleomorphic adenoma	irregular margins, extraglandular extension, facial palsy, rapid growth or suspicious nodes
Bilateral/multifocal	Warthin, Sjögren, HIV, IgG4-related disease, sarcoidosis, lymphoma	integrate age, smoking, sicca, serology, HIV and distribution

Source: ACR-AIUM-SPR-SRU Head and Neck / StatPearls / salivary tumor imaging reviews

Teaching report checklist

Item	Safety question
Coverage	Which gland and side were assessed? Was contralateral comparison performed?
Duct/stone	Was the duct seen? Is there dilatation, transition point, stone with shadow/twinkle or meal-related pain?
Focal lesion	Was the lesion measured in three axes, with margins, content, Doppler, deep plane and nodes?
Sjögren	Were the four major glands scored when the question is sicca/Sjögren?
Communication	Were abscess/gas, facial palsy, extraglandular extension, suspicious nodes or infiltrative mass highlighted?

Source: SonoAI synthesis from cited sources

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