Comparison of Ultrasonography and CT for Determining the Preoperative Benign or Malignant Nature of Thyroid Nodules: Diagnostic Performance According to Calcification

Abstract

Background: The present study was designed to investigate the presence or absence of calcification and whether calcification size affect the diagnostic accuracy of ultrasonography (US) and computed tomography (CT) in predicting the benign or malignant nature of thyroid nodules. Material and Methods: From May 2014 to April 2019, 445 patients underwent thyroid US and neck CT before thyroid surgery. In each case, US and CT were retrospectively examined by radiologists. We divided the patients into 3 groups according to the type of calcification: no calcification, microcalcification, and macrocalcification. And macrocalcification group divided into rim calcifications and non-rim calcifications groups. We evaluated the diagnostic accuracy of US and CT for differentiating malignant from benign thyroid nodules using histopathological results as a reference standard. Results: In the overall population, adding CT to US resulted in greater sensitivity, lower specificity, and lower accuracy in the prediction of the benign or malignant nature of nodules. In the group with no calcification, US had a significantly greater accuracy than CT and combined US/CT. In the group with macrocalcification, especially in rim calcifications, adding CT to US resulted in greater sensitivity than US, and CT exhibited greater sensitivity and accuracy than US. Conclusion: US is superior to CT for the prediction of the benign or malignant nature of nodules in thyroid lesions according to calcification and CT is also currently not recommended as a routine imaging tool for thyroid nodules. However, the superior sensitivity and accuracy of CT in lesions with macrocalcification especially in rim calcifications may enable CT to play a complementary role in identifying benign and malignant nodules.

Cervical lymph node metastases in papillary thyroid cancer

“…Also, the sensitivity of ultrasound is variable and low for central lymph node metastasis [12] . Routine computed tomography is not recommended by the 2015 American thyroid association management guidelines, [7] but computed tomography may use an adjunct to neck ultrasound to assess lymph node metastasis in patients with papillary thyroid cancer before thyroidectomy plus lymph node dissection [8] . Computed tomography plays a complementary role in the assessment of lymph node metastasis before the surgical procedure [13] .…”

“…[7] Also, ultrasound is superior to computed tomography for screening of benign or malignant nature of thyroid nodules. [8,9] However, ultrasound is operator-dependent, and retropharyngeal, retrosternal, and mediastinal regions are difficult to evaluate through Editor: Wen-Wei Sung.…”

“…[12] Routine computed tomography is not recommended by the 2015 American thyroid association management guidelines, [7] but computed tomography may use an adjunct to neck ultrasound to assess lymph node metastasis in patients with papillary thyroid cancer before thyroidectomy plus lymph node dissection. [8] Computed tomography plays a complementary role in the assessment of lymph node metastasis before the surgical procedure. [13] Unlike ultrasound, computed tomography is less operator-dependent and has a potential conclusion regarding lymph node metastasis around esophagus regions but has the risk of exposure to ionizing radiation and risk of future cancers is not addressed in available studies.…”

“…Ultrasound is recommended imaging method for screening of lymph node metastasis in patients with papillary thyroid cancer before thyroidectomy plus lymph node dissection [7] . Also, ultrasound is superior to computed tomography for screening of benign or malignant nature of thyroid nodules [8,9] . However, ultrasound is operator-dependent, and retropharyngeal, retrosternal, and mediastinal regions are difficult to evaluate through ultrasound [10,11] .…”

Identification of benign and malignant thyroid nodules based on dynamic AI ultrasound intelligent auxiliary diagnosis system

“…Ultrasound is the preferred imaging examination to evaluate the benign and malignant thyroid nodules, but the diagnostic results are affected by the factors such as the personal experience of ultrasound doctors, operating skills, ultrasound equipment, and thyroid basic lesions, and the diagnostic accuracy and efficiency of doctors at different levels and with different seniority vary greatly (4)(5)(6). It is pointed out, in the guidelines of the American Thyroid Association that combining the characteristics of nodules under ultrasound and using the Bethesda system judgment, the results of fine needle aspiration cytology (FNAC) is the necessary basis for preoperative judgment of benign and malignant thyroid nodules (7), but there are still cases of omission of malignant nodes and unclear pathological diagnosis in the actual clinical diagnosis.…”