Guidelines for Performing Ultrasound (USG) of the Oral Cavity
Intraoral ultrasound is a valuable diagnostic tool for oral cavity lesions, providing high-resolution imaging of soft tissue structures while avoiding radiation exposure, though it requires specialized equipment and proper technique for optimal results. 1
Equipment Requirements
- Small intraoral transducer (ideally high-frequency 25 MHz) specifically designed for oral cavity use 2
- Acoustic coupling agent (water bag or polymer gel) to ensure proper contact with oral mucosa 3
- Standard ultrasound machine with appropriate settings for small parts imaging
Patient Positioning and Preparation
- Patient should be seated upright or semi-reclined for optimal access to the oral cavity
- Remove any removable dental prostheses prior to examination 1
- Ensure proper infection control measures (transducer covers, sterilization between patients)
Scanning Technique
Anatomical Regions
- Systematic approach examining:
- Tongue (anterior, middle, and posterior thirds)
- Floor of mouth
- Buccal mucosa
- Hard and soft palate
- Gingiva and alveolar ridges
- Tonsils and oropharynx when accessible
Transducer Positioning
- For anterior tongue and floor of mouth: direct intraoral approach 4
- For posterior tongue and base of tongue: transcervical approach may be combined with intraoral views 1
- Multiple planes (longitudinal and transverse) should be obtained for comprehensive evaluation
Image Acquisition
- Apply minimal pressure to avoid tissue distortion
- Use appropriate depth settings (typically 2-3 cm for intraoral structures)
- Document normal anatomical landmarks for reference:
- Tooth surfaces
- Alveolar bone reflection
- Gingival epithelium and subepithelial connective tissue 2
Clinical Applications
Primary Indications
- Evaluation of oral soft tissue lesions:
- Delineation of margins, size, and location 3
- Differentiation between cystic and solid lesions
- Assessment of relationship to adjacent structures
- Staging of oral cavity tumors:
- Assessment of periodontal structures:
- Measurement of gingival thickness
- Evaluation of biological width 2
Secondary Applications
- Monitoring of precancerous lesions 2
- Assessment of implant positioning and surrounding soft tissues 2
- Evaluation of salivary gland pathology (mucoceles, sialoliths)
Limitations and Pitfalls
- Air interference: Air pockets can create artifacts and limit visualization
- Solution: Use adequate coupling gel and proper transducer positioning
- Restricted access: Posterior regions may be difficult to examine thoroughly
- Solution: Combine with transcervical approach when necessary
- Operator dependence: Highly dependent on examiner skill and experience 1
- Solution: Standardized training and protocols
Integration with Other Imaging Modalities
- Ultrasound is complementary to CT and MRI:
Documentation Requirements
- Standard imaging planes with measurements
- Comparison with contralateral normal structures when applicable
- Clear documentation of any pathological findings:
- Size in three dimensions
- Echogenicity (hypo-, iso-, or hyperechoic)
- Margins (well-defined vs. infiltrative)
- Internal characteristics (homogeneous vs. heterogeneous)
- Vascularity (if Doppler capabilities available)
Intraoral ultrasound represents an evolving field in oral diagnostic imaging that offers unique advantages for visualizing soft tissue structures without radiation exposure. While not yet widely implemented in routine practice, its ability to provide high-resolution images of superficial oral lesions makes it a promising tool, particularly for early detection and staging of oral cavity malignancies.