eMedicine Specialties > Radiology > Head/Neck

Thyrotoxicosis: Imaging

Author: John L Floyd, MD, FACR, FRCR, Director of Nuclear Medicine Services, Department of Nuclear Radiology, St Luke's Methodist Hospital and Mercy Medical Center; Consulting Staff, Radiology Consultants of Iowa
Contributor Information and Disclosures

Updated: Oct 13, 2009

Ultrasonography

Findings

Thyroid US is not necessary for the differential diagnosis of thyrotoxicosis, although certain findings are important.

In Graves disease, the thyroid appears normal or moderately enlarged. Color flow imaging demonstrates a general mild-to-marked increased in the blood flow through the parenchyma (see Image 7). With AFTN and TMNG, sonograms demonstrate 1 or more nodules, but they do not indicate the functional status of any nodule.12,13

Color flow ultrasonogram in the same patient as i...

Color flow ultrasonogram in the same patient as in Image 2 in Multimedia. Generalized hypervascularity is visible throughout the gland, which often can be heard as a hum or bruit with a stethoscope.

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Color flow ultrasonogram in the same patient as i...

Color flow ultrasonogram in the same patient as in Image 2 in Multimedia. Generalized hypervascularity is visible throughout the gland, which often can be heard as a hum or bruit with a stethoscope.


In silent and PPT, the gland may be normal, or it may be generally large or plump. The pyramidal lobe may be prominent. The parenchyma may be heterogeneously hyperechoic. With SAT, the gland is edematous; the edema is reflected as hypoechogenicity. This finding can be regional because the gland may not be affected uniformly.

Degree of Confidence

US is generally not used as a diagnostic test for hyperthyroidism. Nevertheless, generalized hypervascularity on color Doppler US is characteristic of diffuse thyrotoxicosis (Graves disease).6

Nuclear Imaging

Findings

Nuclear medicine examinations are used to differentiate the causes of thyrotoxicosis after the diagnosis is made clinically and confirmed by using appropriate laboratory tests. At that point, measurements of thyroid radiotracer uptake with123 I or131 I and findings on a thyroid scan obtained with123 I or99m Tc confirm the diagnosis, and treatment can be initiated.14,15

The Table (above) summarizes the laboratory, thyroid uptake, and radionuclide scanning findings in the various common forms of thyrotoxicosis.

Degree of Confidence

With concordant clinical, laboratory, and imaging findings, confidence in a specific diagnosis is high.

False Positives/Negatives

Normal results on 4- to 24-hour thyroid uptake scans do not preclude a diagnosis of hyperthyroidism. Many multivitamins and other food supplements contain large amounts of iodine, and the extra iodine competes with radioiodine for thyroid clearance. Other sources of iodine ingestion also may be present.

More on Thyrotoxicosis

Overview: Thyrotoxicosis
Imaging: Thyrotoxicosis
Follow-up: Thyrotoxicosis
Multimedia: Thyrotoxicosis
References
Further Reading
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References

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  2. De Waele S, Van den Bruel A, Selleslag D, Van Den Berghe I, Decallonne B. Acute thyrotoxicosis after SCT. Bone Marrow Transplant. Nov 17 2008;[Medline].

  3. Kasagi K, Hattori H. A case of destructive thyrotoxicosis induced by neck trauma. Thyroid. Dec 2008;18(12):1333-5. [Medline].

  4. Motohashi K, Sakai R, Hagihara M, Enaka M, Kanamori H, Maruta A, et al. Thyrotoxicosis after cord blood transplantation for acute myelogenous leukemia. Rinsho Ketsueki. Dec 2008;49(12):1631-3. [Medline].

  5. Romero-Rodríguez N, Cabeza Letrán ML, Villa Gil Ortega M, Ballesteros Pradas S. Thyrotoxicosis-induced vasospastic angina. Rev Esp Cardiol. Dec 2008;61(12):1355-6. [Medline].

  6. Hari Kumar KV, Pasupuleti V, Jayaraman M, Abhyuday V, Rayudu B R, Modi KD. Role of thyroid Doppler in differential diagnosis of thyrotoxicosis. Endocr Pract. Jan-Feb 2009;15(1):6-9. [Medline].

  7. Phillips BD, Hennessey JV. Iodinated contrast prior to evaluation for thyrotoxicosis. J Hosp Med. Mar 4 2009;[Medline].

  8. FDA MedWatch Safety Alerts for Human Medical Products. Propylthiouracil (PTU). US Food and Drug Administration. US Food and Drug Administration. Available at http://www.fda.gov/Safety/MedWatch/SafetyInformation/SafetyAlertsforHumanMedicalProducts/ucm164162.htm. Accessed June 3, 2009.

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  10. Graves RJ. Clinical lectures. London Med Surg J. 1835;(Pt2):516.

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  12. Miles J, Charles P, Riches P. A review of methods available for the identification of both organ- specific and non-organ-specific autoantibodies. Ann Clin Biochem. Jan 1998;35 ( Pt 1):19-47. [Medline].

  13. Loy M, Perra E, Melis A, Cianchetti ME, Piga M, Serra A, et al. Color-flow Doppler sonography in the differential diagnosis and management of amiodarone-induced thyrotoxicosis. Acta Radiol. Jul 2007;48(6):628-34. [Medline].

  14. Floyd JL, Rosen PR, Borchert RD, et al. Thyroid uptake and imaging with iodine-123 at 4-5 hours: replacement of the 24-hour iodine-131 standard. J Nucl Med. Aug 1985;26(8):884-7. [Medline].

  15. Piga M, Cocco MC, Serra A, Boi F, Loy M, Mariotti S. The usefulness of 99mTc-sestaMIBI thyroid scan in the differential diagnosis and management of amiodarone-induced thyrotoxicosis. Eur J Endocrinol. Oct 2008;159(4):423-9. [Medline].

  16. Franklyn JA, Maisonneuve P, Sheppard M, et al. Cancer incidence and mortality after radioiodine treatment for hyperthyroidism: a population-based cohort study. Lancet. Jun 19 1999;353(9170):2111-5. [Medline].

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  18. Bajnok L, Mezosi E, Nagy E, et al. Calculation of the radioiodine dose for the treatment of Graves'' hyperthyroidism: is more than seven-thousand rad target dose necessary?. Thyroid. Sep 1999;9(9):865-9. [Medline].

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  22. Hagen GA, Ouellette RP, Chapman EM. Comparison of high and low dosage levels of 131-I in the treatment of thyrotoxicosis. N Engl J Med. Sep 14 1967;277(11):559-62. [Medline].

  23. Hayek A, Chapman EM, Crawford JD. Long-term results of treatment of thyrotoxicosis in children and adolescents with radioactive iodine. N Engl J Med. Oct 29 1970;283(18):949-53. [Medline].

  24. Hedley AJ, Young RE, Jones SJ, et al. Antithyroid drugs in the treatment of hyperthyroidism of Graves'' disease: long-term follow-up of 434 patients. Scottish Automated Follow- Up Register Group. Clin Endocrinol (Oxf). Aug 1989;31(2):209-18. [Medline].

  25. Kasagi K, Kousaka T, Higuchi K, et al. Clinical significance of measurements of antithyroid antibodies in the diagnosis of Hashimoto''s thyroiditis: comparison with histological findings. Thyroid. Oct 1996;6(5):445-50. [Medline].

  26. Palit TK, Miller CC 3rd, Miltenburg DM. The efficacy of thyroidectomy for Graves'' disease: A meta-analysis. J Surg Res. May 15 2000;90(2):161-5. [Medline].

  27. Roti E, Braverman LE, DeGroot LJ. TCH Receptor Antibody Measurement in the Diagnosis and Management of Graves' Disease Is Rarely Necessary. The Journal of Clinical Endocrinology & Metabolism. 1998;11:3781-3784. [Full Text].

  28. Roti E, Emerson CH. Clinical review 29: Postpartum thyroiditis. J Clin Endocrinol Metab. Jan 1992;74(1):3-5. [Medline].

  29. Singer PA. Thyroiditis. Acute, subacute, and chronic. Med Clin North Am. Jan 1991;75(1):61-77. [Medline].

  30. Torring O, Tallstedt L, Wallin G, et al. Graves'' hyperthyroidism: treatment with antithyroid drugs, surgery, or radioiodine--a prospective, randomized study. Thyroid Study Group. J Clin Endocrinol Metab. Aug 1996;81(8):2986-93. [Medline].

  31. Volpe R. The management of subacute (DeQuervain''s) thyroiditis. Thyroid. Fall 1993;3(3):253-5. [Medline].

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Further Reading

Related eMedicine topics

 Hyperthyroidism  (Endocrinology)

Hyperthyroidism (Pediatrics)

Subacute Thyroiditis

Graves Disease (Pediatrics)

Graves Disease (Endocrinology)

Clinical guidelines

Practice guideline for the performance of therapy with unsealed radiopharmaceutical sources.
American College of Radiology - Medical Specialty Society. 1996 (revised 2005). 13 pages. NGC:005055

Management of thyroid dysfunction during pregnancy and postpartum: an Endocrine Society clinical practice guideline.
The Endocrine Society - Disease Specific Society. 2007. 79 pages.  NGC:005884


Subclinical thyroid disease: scientific review and guidelines for diagnosis and management.
Consensus Conference Panel on Subclinical Thyroid Disease - Independent Expert Panel. 2004 Jan 14. 11 pages. NGC:003902

Clinical trials

 Approach to a Quantitative Follow-up of Non-Thyroidal Illness Syndrome

TSH Receptor Antibody Heterogeneity in Children and Adolescents With Graves' Disease

Color Doppler Imaging of Orbital Venous Flow in Grave's Orbitopathy




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Keywords

thyrotoxicosis, Graves disease, Grave's disease, toxic nodule, toxic multinodular goiter, TMNG, thyroiditis, free thyroxine, T4, triiodothyronine, T3, hyperthyroidism

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Contributor Information and Disclosures

Author

John L Floyd, MD, FACR, FRCR, Director of Nuclear Medicine Services, Department of Nuclear Radiology, St Luke's Methodist Hospital and Mercy Medical Center; Consulting Staff, Radiology Consultants of Iowa
John L Floyd, MD, FACR, FRCR is a member of the following medical societies: American College of Radiology, Radiological Society of North America, and Society of Nuclear Medicine
Disclosure: Nothing to disclose.

Medical Editor

Hussein M Abdel-Dayem, MD, Chief, Nuclear Medicine Service, Department of Radiology, Professor of Radiology, St Vincent's Catholic Medical Centers of New York
Disclosure: none None None

Pharmacy Editor

Bernard D Coombs, MB, ChB, PhD, Consulting Staff, Department of Specialist Rehabilitation Services, Hutt Valley District Health Board, New Zealand
Disclosure: Nothing to disclose.

Managing Editor

C Douglas Phillips, MD, Director of Head and Neck Imaging, Division of Neuroradiology, Weill Medical College of Cornell University/New York Presbyterian Hospital
C Douglas Phillips, MD is a member of the following medical societies: American College of Radiology, American Medical Association, American Society of Head and Neck Radiology, American Society of Neuroradiology, Association of University Radiologists, and Radiological Society of North America
Disclosure: Nothing to disclose.

CME Editor

Robert M Krasny, MD, Resolution Imaging Medical Corporation
Robert M Krasny, MD is a member of the following medical societies: American Roentgen Ray Society and Radiological Society of North America
Disclosure: Nothing to disclose.

Chief Editor

Eugene C Lin, MD, Consulting Radiologist, Virginia Mason Medical Center; Clinical Assistant Professor of Radiology, University of Washington School of Medicine
Eugene C Lin, MD is a member of the following medical societies: American College of Nuclear Medicine, American College of Radiology, Radiological Society of North America, and Society of Nuclear Medicine
Disclosure: Nothing to disclose.

 
 
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