Goiter: Diagnostic Tests

Obligatory medical device diagnostics.

  • Thyroid sonography with duplex/Doppler sonography.
    • Determination of thyroid volume (SD volume)Note in pregnancy: during pregnancy, the mother’s SD volume can double (upper tolerance value: 18 ml)
    • Morphological differentiation of a struma diffusa, struma uni- or multinodosa from other causes of a struma; thyroid malignancies (malignant neoplasms of the thyroid gland):
      • Hypoechogenicity: solid echo-poor nodule* (> 1-1.5 cm)* .
      • Microcalcification*
      • Intranodular vascularization pattern
      • Fuzzy marginal border and the “deeper-than-wide” shape.

      Ultrasound-based “histological” (“fine tissue examination”) diagnosis: sensitivity (percentage of diseased patients in whom the disease is detected by the use of the procedure, i.e., a positive finding occurs) of 83-99%, specificity 56-85% (probability that actually healthy people who do not have the disease in question are also detected as healthy by the procedure) Three criteria decide the pros or cons of biopsy (tissue sampling; here: Fine needle aspiration cytology (FNAZ)): Microcalcifications, size greater than 1-1.5 cm, completely solid consistency (= echo-poor) – these three sonographic criteria are associated with the risk of malignancy of a thyroid nodule. Purely cystic and/or spongiform nodules can usually be observed conservatively.

  • Elastography (imaging technique that measures the elasticity of tissue) – if thyroid carcinoma is suspected (malignancies show altered tissue consistency; elastography shows decreased compressibility).

Optional medical device diagnostics – depending on the results of the history, physical examination and obligatory laboratory parameters – for differential diagnostic clarification.

  • Thyroid scintigraphy – to be performed for the following indications:
    • Nodular changes of the thyroid gland (uni- or multinodular nodular goiter* ): in Germany, a basic scintigraphy (independent of the TSH value) is recommended once for nodules > 10 mm (due to iodine deficiency in Germany); in the case of multinodular goiter, a scintigraphy is recommended in any case to identify non-autonomous nodules, if necessary (in this case, a biopsy (tissue sampling; in this case: fine-needle aspiration cytology, FNAZ) must be performed to verify the dignity)
    • Suspicion of thyroid carcinoma (thyroid cancer).
    • Suspected hyperthyroidism (hyperthyroidism) with autonomous areas (independence of parts of the thyroid tissue from the thyrotropic control circuit (hypothalamus-pituitary-thyroid), so that the synthesis (production) of thyroid hormones does not occur as needed).

* Identification of suspicious nodules, when focusing on cold and non-autonomous areas, when sonographically abnormal findings.

Further notes

  • If thyroid autonomy is detected, clarification of a dignity of the nodule (clarification of whether the nodule is benign or malignant) can be omitted, because as a rule autonomous adenomas are benign (benign).
  • Current guidelines advise sonographically conspicuous nodules, depending on nodule size, to be monitored regularly by ultrasound or fine-needle biopsy. A study that followed nearly 1,000 patients with more than 1,500 thyroid nodules diagnosed as benign over 5 years reached the following conclusions:
    • Thyroid carcinoma was identified in five nodules (0, 3%). Four of these were from the group that had already been punctured at baseline based on suspicious (“suspect”) sonographic criteria, i.e., only 1.1% of the biopsied nodules were classified as false negatives!
    • Only one of 852 nodes <1 cm (0.1%) showed malignancy (malignancy) during follow-up. The nodule did not become conspicuous until the 5th year and showed hypoechogenicity (weakly reflective, echo-poor structures) and fuzzy borders on ultrasound.
    • Nodal growth was usually apparent quite early, often in the first year.

    Conclusion: in the case of small (< 1 cm) and cytologically inconspicuous nodes, a follow-up examination after one year is sufficient. If there is no growth, another examination in 5 years is sufficient. Exceptions are young patients or older obese patients with multiple or large nodes (size < 7.5 mm).

  • Thyroid incidentalomas (incidental discovery of a nodule of unclear significance): of 1153 patients, 37.4% underwent biopsy for a thyroid nodule; patients were significantly more likely to be >45 years old, men, white race, and had a body mass index>30 kg/m2; of the 17.2% of incidentalomas that resulted in surgery, 8.5% were classified as thyroid carcinoma.
  • In childhood and adolescence, thyroid nodules are usually benign (benign). Nodules with a diameter > 1 cm should be clarified by fine needle aspiration cytology (FNAZ) after determination of TSH and calcitonin.
  • With age, the number of thyroid nodules increases, but their malignancy risk decreases at the same time: cancer prevalence:
      • 22.9% in the youngest young age group (20-29 years).
      • 12, 6% in the highest age group (≥ 70 years).

    The relative risk of malignant nodules decreased by 2.2% annually between 20 and 60 years of age.

  • Ultrasound screening for thyroid abnormalities in the elderly over 60 years of age should not be performed.

Note: Clear clinical malignancy criteria (criteria of malignancy) should always be given higher priority than conflicting benign (benign) results of fine needle aspiration cytology (targeted sampling of suspicious tissue examined under a microscope). That is, clear clinical malignancy criteria alone may lead to surgery.