Contrast agent retention features in contrast-enhanced ultrasound: diagnostic performance for the prediction of papillary thyroid carcinoma

Abstract

PurposeTo report a new feature of contrast-enhanced ultrasound (CEUS) and its diagnostic performance for the prediction of papillary thyroid carcinoma (PTC). MethodsThis retrospective study was conducted from October 2018 to March 2019, including 276 patients with 308 thyroid nodules who underwent CEUS examinations prior to surgery (90 patients, 122 nodules) or fine needle aspiration (186 patients, 186 nodules). Quantitative analysis of CEUS features was performed using time-intensity curves. After surgery, tissue sections stained with HE and an anti-CD34 primary antibody were used to characterize the cell number and microvessel density. The nodules were divided into retention and non-retention groups. ResultsThere were 168 malignant nodules and 140 benign nodules. The contrast-agent retention (CAR) feature was only observed in 52 papillary carcinomas. The CAR feature showed the sensitivity of 30.9% albeit the high specificity of 100%, for the diagnosis of thyroid cancers. The maximum slope coefficient of the washout index was significantly lower in the retention group than in the non-retention group (P < 0.001). The enhancement intensity during the late stage of enhancement index was significantly higher in the retention group than in the non-retention group (P < 0.001). The cell number and microvessel density in nodules with CAR features were higher (P < 0.001, P = 0.004). ConclusionThe combination of the retention pattern of the CEUS observed herein with other CEUS features may be a useful tool to improve the diagnostic of the PTC.