Combination of Lymphatic and Intravenous Contrast-Enhanced Ultrasound for Evaluation of Cervical Lymph Node Metastasis from Papillary Thyroid Carcinoma: A Preliminary Study

Abstract

The aim of this prospective study was to evaluate the value of the combination of lymphatic contrastenhanced ultrasound (LCEUS) and intravenous contrast-enhanced ultrasound (IVCEUS) for the identification of cervical lymph node metastasis (CLNM) from papillary thyroid carcinoma (PTC). From November 2018 to March 2019, 24 consecutive patients with PTC were evaluated. All patients underwent routine US, LCEUS and IVCEUS. Pathology was used as the gold standard. After injection of a contrast agent into the thyroid parenchyma, lymphatic vessels and lymph nodes (LNs) could be exclusively displayed as hyper-enhancement on LCEUS. Benign LNs displayed a complete bright ring (100%) and homogeneous perfusion (88.9%) on LCEUS, while displaying centrifugal perfusion (66.7%) and homogenous enhancement (88.9%) on IVCEUS. Perfusion defects (94.9%) and interruption of the bright ring (71.8%) were the two characteristic LCEUS signs for diagnosing CLNM. On IVCEUS, CLNM appeared as centripetal perfusion (59.0%) and heterogeneous enhancement (59.0%). After comparison with pathology, perfusion defect was correlated to the metastatic foci in the medulla and interruption of the bright ring to the tumor seeding in the marginal sinus (all p values <0.05). LCEUS had more value (area under the receiver operating characteristic curve [AUC] = 0.850, 95% confidence interval [CI]: 0.682À1.000) in diagnosing CLNM than IVCEUS (AUC = 0.692, 95% CI: 0.494À0.890) and routine US (AUC = 0.581, 95% CI: 0.367À0.796). The combination of LCEUS and IVCEUS has the highest diagnostic value (AUC = 0.863, 95% CI: 0.696À1.000). LCEUS had higher diagnostic value than IVCEUS and US for CLNM from PTC. The combination of LCEUS and IVCEUS has the highest diagnostic value for CLNM.

The value of contrast‐enhanced ultrasound for the diagnosis of metastatic cervical lymph nodes of papillary thyroid carcinoma: A systematic review and meta‐analysis

“…20 1.20 ml in four studies, 9,13,22,23 1 ml in one study, 21 and 0.40 ml in one study. 24 The scan time after injecting contrast agent was 180 s or more in one study, 21 120 s or more and less than 180 s in four studies, 9,20,22,23 90 s in one study, 13 and 30 s in one study. 24 All of the studies reported saline was used after contrast agent injection, except one study that did not describe the dose of saline used, 24 the other six articles all used 5 ml of saline.…”

“…Seven articles were included with 1049 patients and 894 lymph nodes. 9,13,[20][21][22][23][24] The number of lymph nodes varied from 48 to 319 in a single study. The mean patient ages of the included studies varied from 35.00 ± 6.20 to 52.60 ± 13.50.…”

“…The pathologic type of patients was proven PTC in all studies. Five articles were prospective design types, 9,20,[22][23][24] while in other two articles were retrospective. 13,21 Four of the included articles assessed the diagnostic efficacy of CEUS preoperatively, 9,21,23,24 one article evaluated it postoperatively, 22 one study assessed it both preoperatively and postoperatively, 20 and one article was not specified.…”

“…Five articles were prospective design types, 9,20,[22][23][24] while in other two articles were retrospective. 13,21 Four of the included articles assessed the diagnostic efficacy of CEUS preoperatively, 9,21,23,24 one article evaluated it postoperatively, 22 one study assessed it both preoperatively and postoperatively, 20 and one article was not specified. 13 T A B L E 2 CEUS characteristics and criteria of the included studies F I G U R E 2 Bias of the included studies according to the QUADAS-2 tool Except for one article using Sonazoid, 24 the remaining six articles used SonoVue as the contrast agent.…”

“…9,13,[20][21][22][23] CEUS criteria for CLNM were almost qualitative parameters, including enhancement direction, enhancement type, enhancement range, and calcification. Qualitative criteria were used in six articles, 9,13,[20][21][22]24 while an article used qualitative and quantitative features for statistical analysis. 23 Therefore, we have obtained a total of eight available datasets from seven articles.…”