Diagnostic Performance of Margin Features in Thyroid Nodules in Prediction of Malignancy.

OBJECTIVE: The purpose of this study was to evaluate thyroid nodule margins for specific morphologic features and determine the diagnostic performance of these features in differentiating papillary carcinoma from benign thyroid nodules. MATERIALS AND METHODS: Nodules measuring 1-3 cm in largest diameter that had been evaluated with high-resolution ultrasound (12-18 MHz) and ultrasound-guided biopsy with definitive pathologic diagnosis were analyzed. Three blinded board-certified readers evaluated high-resolution images of each nodule for jagged edges, lobulated borders, and curved borders along their margins. Reader interpretations were correlated with the pathologic diagnosis to determine the diagnostic performance of each feature. A board-certified pathologist analyzed 10 randomly selected nodules with jagged edges by slide review to evaluate for structural correlation with the imaging finding. RESULTS: The diagnostic performance of jagged edges in papillary carcinoma of the thyroid was 67.4% sensitive and 78.3% specific (odds ratio, 7.44; p < 0.001) for malignancy. Jagged edges correlated with infiltrative variant expansion at slide review. Lobulated borders had sensitivity of 76.1% and specificity of 60.9% for papillary carcinoma (odds ratio, 4.95; p = 0.001) for malignancy. Curved borders were not a significant predictor of papillary carcinoma. CONCLUSION: Jagged edges and lobulated borders of thyroid nodule margins are statistically significant predictors of papillary carcinoma of the thyroid. Jagged edges correlate with infiltrative-type expansion and may be useful predictors of more aggressive papillary carcinomas.

Sonographic-Pathologic Correlation for Punctate Echogenic Reflectors in Papillary Thyroid Carcinoma: What Are They?

OBJECTIVES: It is commonly held that punctate nonshadowing echogenic foci on sonography, often termed microcalcifications, represent psammoma bodies. We aimed to determine the validity of this supposition by correlating the presence of punctate echogenic foci on sonography with their presence at histopathologic examination. METHODS: We examined 51 nodules (surgically proven papillary thyroid carcinoma) by sonography and histopathologic examination. On the latter, nodules were examined for evidence of psammomatous calcifications, dystrophic calcifications, and colloid. Two subspecialty-trained radiologists with 2 and 25 years of experience in sonography, respectively, reviewed the sonograms for the presence and distribution of punctate echogenic foci. RESULTS: All nodules contained colloid at histologic examination. Twenty of the papillary carcinomas lacked any calcification at pathologic examination. In the remaining 31 nodules with calcifications, 13 had psammomatous calcifications only; 6 had both coarse and psammomatous calcifications; and 12 had only coarse calcifications. The presence of punctate echogenic foci on sonography was 74% sensitive, was 46% to 53% specific, and had a positive predictive value of only 45% to 48% for the presence of psammomatous calcifications. The computed 2-tailed P value indicated that the punctate echogenic foci-to-psammoma body correlation was not statistically significant. CONCLUSIONS: The sonographic signature commonly referred to as "microcalcifications" may represent a variety of entities, including psammomatous calcifications, dystrophic calcifications, and eosinophilic colloid; for this reason, "punctate echogenic foci" would be a more accurate term.

Sonographic Detection of Extracapsular Extension in Papillary Thyroid Cancer.

OBJECTIVES: To identify and evaluate sonographic features suggestive of extracapsular extension in papillary thyroid cancer. METHODS: Three board-certified radiologists blinded to the final pathologic tumor stage reviewed sonograms of pathologically proven cases of papillary thyroid cancer for the presence of extracapsular extension. The radiologists evaluated the following features: capsular abutment, bulging of the normal thyroid contour, loss of the echogenic capsule, and vascularity extending beyond the capsule. RESULTS: A total of 129 cases of pathologically proven thyroid cancer were identified. Of these, 51 were excluded because of lack of preoperative sonography, and 16 were excluded because of pathologic findings showing anaplastic carcinoma, follicular carcinoma, or microcarcinoma (<10 mm). The final analysis group consisted of 62 patients with papillary thyroid carcinoma, 16 of whom had pathologically proven extracapsular extension. The presence of capsular abutment had 100% sensitivity for detection of extracapsular extension. Conversely, lack of capsular abutment had a 100% negative predictive value (NPV) for excluding extracapsular extension. Contour bulging had 88% sensitivity for detection of extracapsular extension and when absent had an 87% NPV. Loss of the echogenic capsule was the best predictor of the presence of extracapsular extension, with an odds ratio of 10.23 (P = .034). This sonographic finding had 75% sensitivity, 65% specificity, and an 88% NPV. Vascularity beyond the capsule had 89% specificity but sensitivity of only 25%. CONCLUSIONS: Sonographic features of capsular abutment, contour bulging, and loss of the echogenic thyroid capsule have excellent predictive value for excluding or detecting extracapsular extension and may help in biopsy selection, surgical planning, and treatment of patients with papillary thyroid cancer.

Bowel obstruction complicated by ischemia: analysis of CT findings.

PURPOSE: To analyze CT signs of bowel ischemia in patients with surgical bowel obstruction, and thereby improve CT diagnosis in this common clinical scenario. Surgical and histopathological findings were used as the reference standard. METHODS: We retrospectively analyzed CT findings in patients brought to surgery for bowel obstruction over 13 years. Etiology of obstruction (adhesion, hernia, etc.) was recorded. Specific CT features of acute mesenteric ischemia (AMI) were analyzed, including bowel wall thickening, mucosal hypoenhancement, and others. RESULTS: 173 cases were eligible for analysis. 21% of cases were positive for bowel ischemia. Volvulus, internal hernia, and closed-loop obstructions showed ischemia rates of 60%, 43%, and 43%; ischemia rate in obstruction from simple adhesion was 21%. Patients with bowel obstruction related to malignancy were never ischemic. Sensitivities and specificities for CT features predicting ischemia were calculated, with wall thickening, hypoenhancement, and pneumatosis showing high specificity for ischemia (86%-100%). CONCLUSION: Wall thickening, hypoenhancement, and pneumatosis are highly specific CT signs of ischemia in the setting of obstruction. None of the evaluated CT signs were found to be highly sensitive. Overall frequency of ischemia in surgical bowel obstruction is 21%, and 2-3 times that for complex obstructions (volvulus, closed loop, etc.). Obstructions related to malignancy virtually never become ischemic.

Atypical thyroid cancers on sonography.

The management of thyroid nodules is a common clinical problem. Thyroid nodules are present in up to 50% of the adult population. However, thyroid malignancy is rare, occurring in only 5% to 15% of nodules. Although certain specific patterns on imaging are almost always indicative of benignity, there is considerable overlap between the sonographic appearances of benign and malignant nodules. Radiologists should be wary of applying pattern recognition approaches too liberally as some malignant nodules may exhibit sonographic features more commonly associated with benign nodules such as cystic change, comet-tail artifact, smooth margins, echogenic echotexture, hypoechoic halos, or peripheral calcifications. This article illustrates atypical imaging appearances of thyroid malignancies and reviews recent literature in an attempt to clarify nuances in the diagnosis of malignancy in benign-appearing nodules.