Thyroid Ultrasound Physics

  • Robert A. LevineEmail author


The thyroid is well suited to ultrasound examination due to its size, superficial location, and characteristic echotextures in health and disease. Ultrasound imaging uses the reflection of high frequency sound waves to create a visual image. Unlike electromagnetic energy, sound transmission is dependent on, and greatly influenced by, the conducting medium. Sound is reflected at interfaces of mismatch of acoustic impedance. The resolution of an ultrasound image is dependent on the frequency, the focused beam width, and the quality of the electronic processing. Resolution improves, but the depth of imaging decreases, with higher frequencies. Image artifacts such as shadowing and posterior acoustic enhancement provide useful information, rather than just interfering with creation of a clear image. The current image quality, affordable cost, and ease of performance make real-time ultrasound an integral part of the clinical evaluation of the thyroid patient.


Speed of sound Frequency Acoustic impedance Resolution Reflection Refraction A-mode B-mode Artifacts Acoustic shadowing Acoustic enhancement Attenuation Comet tail artifact Transducer Compound spatial imaging 







Meters per second


  1. 1.
    Meritt CRB. Physics of ultrasound. In: Rumack CM, Wilson SR, Charboneau JW, Levine D, editors. Diagnostic ultrasound. 4th ed. St. Louis: Mosby; 2011. p. 2–33.Google Scholar
  2. 2.
    Levine RA. Something old and something new: a brief history of thyroid ultrasound technology. Endocr Pract. 2004;10(3):227–33.CrossRefGoogle Scholar
  3. 3.
    Coltrera MD. Ultrasound physics in a nutshell. Otolaryngol Clin N Am. 2010;43(6):1149–59.CrossRefGoogle Scholar
  4. 4.
    Ahuja A, Chick W, King W, Metreweli C. Clinical significance of the comet-tail artifact in thyroid ultrasound. J Clin Ultrasound. 1996;24(3):129–33.CrossRefGoogle Scholar
  5. 5.
    Beland MD, Kwon L, Delellis RA, Cronan JJ, Grant EG. Non-shadowing echogenic foci in thyroid nodules: are certain appearances enough to avoid thyroid biopsy? J Ultrasound Med. 2011;30(6):753–60.CrossRefGoogle Scholar
  6. 6.
    Tahvildari AM, Pan M, Kong CS, Desser T. Sonographic pathologic correlation for punctate echogenic reflectors in papillary thyroid carcinoma. What are they? J Ultrasound Med. 2016;35(8):1645–52.CrossRefGoogle Scholar
  7. 7.
    Malhi H, Beland MD, Cen SY, Allgood E, et al. Echogenic foci in thyroid nodules: significance of posterior acoustic artifacts. Am J Roentgenol. 2014;203(6):1310–6.CrossRefGoogle Scholar
  8. 8.
    Szopinski KT, Wysocki M, Pajk AM, et al. Tissue harmonic imaging of thyroid nodules: initial experience. J Ultrasound Med. 2003;22(1):5–12.CrossRefGoogle Scholar
  9. 9.
    Lin DC, Nazarian L, O’Kane PL, et al. Advantages of real-time spatial compound sonography of the musculoskeletal system versus conventional sonography. Am J Roentgenol. 2002;179(6):1629–31.CrossRefGoogle Scholar
  10. 10.
    Shapiro RS, Simpson WL, Rauch DL, Yeh HC. Compound spatial sonography of the thyroid gland: evaluation of freedom from artifacts and of nodule conspicuity. Am J Roentgenol. 2001;177:1195–8.CrossRefGoogle Scholar
  11. 11.
    Kim GR, Kim EK, Kim SJ, Ha EJ, et al. Evaluation of underlying lymphocytic thyroiditis with histogram analysis using grayscale ultrasound images. J Ultrasound Med. 2016;35(3):519–26.CrossRefGoogle Scholar
  12. 12.
    Song G, Xue F, Zhang CA. Model using texture features to differentiate the nature of thyroid nodules on sonography. J Ultrasound Med. 2015;34(10):1753–60.CrossRefGoogle Scholar
  13. 13.
    Ardakani AA, Gharbali A, Mohammadi A. Classification of benign and malignant thyroid nodules using wavelet texture analysis of sonograms. J Ultrasound Med. 2015;34(11):1983–9.CrossRefGoogle Scholar

Copyright information

© Springer International Publishing AG 2018

Authors and Affiliations

  1. 1.Geisel School of Medicine at Dartmouth College, Thyroid Center of New Hampshire, St. Joseph HospitalNashuaUSA

Personalised recommendations