CT features of thyroid nodules with isolated macrocalcifications detected by ultrasonography

Abstract

Purpose: A thyroid nodule with an isolated macrocalcification is visualized as a calcified nodule with complete posterior shadowing on ultrasonography (US). This study aimed to determine the computed tomography (CT) features of isolated macrocalcifications detected using US. Methods: This study included 20 patients who had thyroid nodules with isolated macroalcifications and underwent neck CT or chest CT. The patients were enrolled from a sample of 82 patients with isolated macrocalcifications detected by US drawn from 7,142 consecutive patients who underwent thyroid biopsy at two institutions. We evaluated the CT features of nodules with isolated macrocalcifications and categorized them as central or rim calcifications. We assessed the nodule size and the frequency of nondiagnostic fine-needle aspiration (FNA) results and malignant tumors according to the CT features of isolated macrocalcifications. Results: CT scans showed central calcifications in 18 (90.0%) and rim calcifications in two (10.0%) of the 20 nodules with isolated macrocalcifications. Among the 18 nodules with central isolated macrocalcifications, complete compact calcification was found in six nodules and partial coarse calcification in 12 nodules. In 18 nodules with central isolated macrocalcifications, the nondiagnostic FNA rate and frequency of malignant tumors were not significantly different between complete and partial central calcifications (P=0.620 and P=0.999, respectively). Malignant tumors were only found in nodules with central isolated macrocalcifications. Conclusion: The majority of nodules with isolated macrocalcifications showed central calcifications on CT. Thyroid nodules with isolated macrocalcifications detected by US should not be classified as having a type of rim or peripheral calcification.

Re: Clinical significance of isolated macrocalcifications detected by ultrasonography

“…Therefore, even though the KSThR guideline currently recommends biopsy for isolated macrocalcifications only when the nodule size is equal to or larger than 1 cm, US monitoring of small isolated macrocalcifications may be necessary. Although our study revealed that the majority of isolated macrocalcifications are composed of coarse central calcifications [5], the histopathologic features of isolated macrocalcifications have only been investigated to a limited extent. We agree that the investigation of histopathologic features using core-needle biopsy specimen would be useful for identifying the characteristics of benign and malignant isolated macrocalcifications, which will be another step towards understanding the nature of isolated macrocalcifications in the thyroid gland.…”

Clinical significance of isolated macrocalcifications detected by ultrasonography

“…We read with great interest the article published by Paik et al entitled "CT features of thyroid nodules with isolated macrocalcifications detected by ultrasonography" in Ultrasonography [1]. The authors evaluated isolated macrocalcifications (IMs) in the thyroid gland using ultrasonography (US) and computed tomography (CT).…”

“…The risk of malignancy of IMs seems to be 10%-20% [5]. The classification of the US lexicon plays an important role in the risk stratification of thyroid nodules for malignancy [1]. IMs are categorized as intermediate suspicion nodules in the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) [6] and as moderately suspicious nodules in the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) [7].…”

“…IMs are categorized as intermediate suspicion nodules in the Korean Thyroid Imaging Reporting and Data System (K-TIRADS) [6] and as moderately suspicious nodules in the American College of Radiology Thyroid Imaging Reporting and Data System (ACR TI-RADS) [7]. However, this has not been specified in the risk stratification of thyroid nodules in other thyroid society guidelines [1].…”

“…The authors evaluated isolated macrocalcifications (IMs) in the thyroid gland using ultrasonography (US) and computed tomography (CT). They defined IMs as isolated, calcified thyroid nodules with complete posterior acoustic shadowing in which no solid component was obviously identified within the nodules on US [ 1 ]. Their concern about IMs was that previous studies have either not clearly defined IMs [ 2 ] or categorized them incorrectly (as rim or peripheral calcifications) [ 3 , 4 ].…”