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 Table of Contents  
Year : 2020  |  Volume : 15  |  Issue : 3  |  Page : 515-516

Comet tail artifact in thyroid nodule on ultrasonography: A marker of benignity

Department of Radio Diagnosis, Jawaharlal Nehru Medical College, Datta Meghe Institute of Medical Sciences (Deemed to be University), Wardha, Maharashtra, India

Date of Submission11-May-2020
Date of Decision20-May-2020
Date of Acceptance02-Nov-2020
Date of Web Publication1-Feb-2021

Correspondence Address:
Dr. Suresh Phatak
Department of Radiodiagnosis, Jawaharlal Nehru Medical College, Sawangi (Meghe), Wardha - 442 001, Maharashtra
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/jdmimsu.jdmimsu_182_20

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How to cite this article:
Singh V, Phatak S, Chaudary K, Patwa P. Comet tail artifact in thyroid nodule on ultrasonography: A marker of benignity. J Datta Meghe Inst Med Sci Univ 2020;15:515-6

How to cite this URL:
Singh V, Phatak S, Chaudary K, Patwa P. Comet tail artifact in thyroid nodule on ultrasonography: A marker of benignity. J Datta Meghe Inst Med Sci Univ [serial online] 2020 [cited 2021 Mar 7];15:515-6. Available from: http://www.journaldmims.com/text.asp?2020/15/3/515/308553

Dear Editor,

The word artifact comes from the Latin word - arte (by skill) and factum (to do); it is defined as a characteristic product of human activity and a product of artificial character due to an extraneous agency.[1] Artifacts are very common in ultrasonography (USG). While some are unwanted and hamper the imaging quality, others may reveal a valuable information related to the structure and composition of the underlying tissue.[2] There are various artifacts known in USG such as acoustic enhancement, acoustic shadowing, aliasing artifact, beam width artifact, comet tail artifact, mirror image artifact, side lobe artifact, and twinkling artifact. In this letter, we focus on comet tail artifacts and its significance. In the presence of two parallel highly reflective surfaces, when ultrasound echoes generated from a primary beam hit the reflective target, they may be repeatedly reflected back and forth before returning to the transducer for detection. When this occurs, multiple echoes are recorded and displayed; this phenomenon is known as reverberation artifact. Comet tail artifact is a type of reverberation artifact in which the two reflective surfaces are very closely placed; hence, on the display, the sequential echoes are so close together that individual signals are not perceivable[3] [Figure 1]. Comet tail artifacts are clinically useful; they are produced by highly reflective surfaces such as cholesterol crystals seen in adenomyomatosis of the gallbladder or inspissated colloid in benign colloid nodules of the thyroid. They may also be seen with small calcifications and metal objects as seen in foreign bodies and surgical clips, respectively.[2] We present a case of 42-year-old female patient, with a history of hypothyroidism who came for routine USG of the neck. The sonography finding revealed multiple, varied sized cysts diffusely spread throughout both the lobes of thyroid with hyperechoic foci in every cyst showing comet tail artifacts [Figure 2]. Comet tail artifacts can be further classified into small comet tail artifacts (=1 mm long) and echogenic foci with large comet tail artifacts (>1 mm long), of which the large comet tail artifacts are more commonly found in cystic lesion like the thyroid nodule. There are various indicators to differentiate a benign thyroid nodule from malignant one, with large comet tail artifact being one of them. According to the literature, the presence of large, triangular comet tail artifacts, however, can generally be considered a sign that a nodule is benign and that biopsy can be avoided,[4] and the presence of the comet tail artifact appears to be a useful indicator of benignity with a sensitivity and specificity of 100%.[5],[6],[7],[8],[9],[10]
Figure 1: Ultrasound physics of comet tail artifact

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Figure 2: Varied sized cysts diffusely spread throughout the lobe of the thyroid with hyperechoic foci within showing comet tail artifact

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Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

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Conflicts of interest

There are no conflicts of interest.

  References Top

Kremkau FW, Taylor KJ. Artifacts in ultrasound imaging. J Ultrasound Med 1986;5:227-37.  Back to cited text no. 1
Baad M, Lu ZF, Reiser I, Paushter D. Clinical significance of US artifacts. Radiographics 2017;37:1408-23.  Back to cited text no. 2
Feldman MK, Katyal S, Blackwood MS. US artifacts. Radiographics 2009;29:1179-89.  Back to cited text no. 3
Malhi H, Beland MD, Cen SY, Allgood E, Daley K, Martin SE, et al. Echogenic foci in thyroid nodules: Significance of posterior acoustic artifacts. Am J Roentgenol 2014;203:1310-6.  Back to cited text no. 4
Ahuja A, Chick W, King W, Metreweli C. Clinical significance of the comet-tail artifact in thyroid ultrasound. J Clin Ultrasound 1996;24:129-33.  Back to cited text no. 5
Jose AM, Muntode PA, Sharma S, Mathew SS, Nair RR, Solanki S. Profile of Thyroid Dysfunctions among the Female Population in a Rural Community of Wardha District: A Hospital based Study. J Datta Meghe Inst Med Sci Univ 2019;14:S87-91. Available from : https://doi.org/10.4103/jdmimsu.jdmimsu_231_19. [Last accessed on 2020 Mar 07].  Back to cited text no. 6
Balwani MR, Pasari A, Meshram A, Jawahirani A, Tolani P, Laharwani H, et al. An Initial Evaluation of Hypokalemia Turned out Distal Renal Tubular Acidosis Secondary to Parathyroid Adenoma. Saudi Journal of Kidney Diseases and Transplantation: An Official Publication of the Saudi Center for Organ Transplantation, Saudi Arabia 2018;29:1216-9. Available from : https://doi.org/10.4103/1319-2442.243965. [Last accessed on 2020 Mar 07].  Back to cited text no. 7
Gulve SS, Phatak SV. Parathyroid Adenoma: Ultrasonography, Doppler, and Elastography Imaging. ital based Study. J Datta Meghe Inst Med Sci Univ 2019;14:47-9. Available from : https://doi.org/10.4103/jdmimsu.jdmimsu_91_18. [Last accessed on 2020 Mar 07].  Back to cited text no. 8
  [Full text]  
Wagh SP, Bhagat SP, Bankar N, Jain K. Relationship between Hypothyroidism and Body Mass Index in Women: A Cross-Sectional Study. Int J Cur Res Rev 2020;12:48-51. Available from : https://doi.org/10.31782/IJCRR.2020.12129. [Last accessed on 2020 Mar 07].  Back to cited text no. 9
Jaiswal N, Makrande J, Bhake A, Bapat AV. Ema, Vimentin, Desmin, Calretinin, e-Cadherin on Cell Block to Differentaite Adenocarcinoma Cells from Benign Reactive Mesothelial Cells. Int J Pharm Res 2019;11: 1860-4. Available from :https://doi.org/10.31838/ijpr/2019.11.02.213. [Last accessed on 2020 Mar 07].  Back to cited text no. 10


  [Figure 1], [Figure 2]


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