ULTRASONOGRAPHY

September 14, 2024
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TOPIC: ULTRASONOGRAPHY

🌟IMPORTANT POINTS TO REMEMBER

🔹USG: It is also defined as the study of tissues of the human body with the utilisation of reflections (echoes) of high-frequency sound waves (USs) which are introduced on the body surface, in the area under examination, by a device called ‘a transducer’. The word ‘sonography’ means imaging with US.

🔹Principle of USG: The USG unit consists of a transducer and the monitor on which sonogram can be seen. The transducer generates the high-frequency sounds by means of ‘piezoelectric effect’, produced by a special kind of crystal located in the transducer which will vibrate when stimulated by electricity.

🔹Acoustic Impedance: The degree of reflection or absorption of the travelling USs at a tissue interface is a function of the acoustic impedance of the tissue.

🔹Types: USG generally falls in two main categories: transverse sections or images are sections produced perpendicular to the long axis of the tissue or organ of interest, and longitudinal sections or images are the ones produced parallel to the long axis of the tissue or organ of interest.

🔹Image Interpretation: In current US machines, echoes are being processed at a sufficiently rapid rate to allow perception of motion; this is known as real-time imaging. A sonogram is the digital image of the received and processed reflected sound waves, projected on a computer screen.

🔹Applications Of USG In Oral And Maxillofacial Imaging: Detection of benign and malignant masses, detection of inflammatory soft tissue conditions, detection of orofacial fracture and detection of thickness of muscles.

🔹USG In Salivary Gland Pathologies: Inflammatory conditions of salivary glands, sialolithiasis and salivary gland tumours.

🔹When a patient is presented with a palpable mass in the salivary gland region or mass is suspected, diagnostic USG can be employed to confirm the presence of a mass, differentiate between intraglandular and extraglandular lesions, and suggest nature of the mass (benign vs. malignant).

🔹USG Of Neck: It helps in evaluation of submandibular region up to the supraclavicular region and helps recognise neck masses, diseases and developmental masses related to submandibular space and associated triangles, anterior and posterior triangles, pathologies associated with thyroid and parathyroid glands, larynx, pharynx,trachea, neck muscles and fascia and lymph nodes.

🔹USG For Vascular Structures In Orofacial Region: The colour Doppler US imaging with the B-mode using the Doppler effect of flow in blood vessels is commonly being used.

🔹USG As Guiding Or Interventional Tool: US-guided interventions in form of biopsies or surgeries are gaining importance these days. They can also be used during FNAC, and the central sampling of a solid lesion is more 

reliable than peripheral sampling.

📌 MULTIPLE CHOICE QUESTIONS (MCQs)

💡Transducer

  1. Generates high-frequency sound waves (ultrasound) through piezoelectric effect
  2. Contains a crystal that vibrates when stimulated by electricity
  3. Converts electrical signal into mechanical motion and mechanical motion into ultrasound
  4. All of the above

Answer: 4

💡 ___ is an expression of the opposition to the passage of sound waves and it is a reflection of tissue density and elasticity.

  1. Piezoelectric effect
  2. Acoustic impedance
  3. Echogenicity
  4. None of the above

Answer: 2

💡In ultrasonography, various tissues and structures are categorized based on their ability to reflect sound waves, which are

  1. Hyperechoic
  2. Hypoechoic
  3. Anechoic
  4. All of the above

Answer : 4

💡Glandular tissue appears in sonographic images as

  1. Hyperechoic
  2. Moderately echogenic
  3. Hypoechoic
  4. Anechoic

Answer: 2

💡Muscles and blood vessels appear in sonographic images as

  1. Hyperechoic
  2. Hypoechoic
  3. Anechoic
  4. None of the above

Answer: 2

💡Ultrasonography

  1. Is the tomographic imaging technique
  2. It is simple, inexpensive, non-invasive
  3. It is used in the detection of moving tissue, cardiac motion
  4. Has diagnostic approach on vascular pathology and blood flow
  5. All of the above

Answer: 5

💡Sialoliths appear ___ in sonography images.

  1. Hyperechoic
  2. Hypoechoic
  3. Anechoic
  4. Could not be diagnosed

Answer: 1

💡Salivary gland tumours appear

  1. Hyperechoic
  2. Hypoechoic
  3. Anechoic
  4. None of the above

Answer: 2

💡Which of the following is not true for the appearance of malignant salivary gland tumours?

  1. Well-circumscribed with sharp borders
  2. Heterogeneous structures
  3. Presence of fluid-filled cystic spaces (necrosis)
  4. Higher blood flow (vascularity)

Answer: 1

💡Tongue tumours appear ___ in comparison to surrounding tongue muscles.

  1. Hyperechoic
  2. Hypoechoic
  3. Anechoic
  4. Moderately echogenic

Answer: 2

Oral Medicine and Radiology