The role of multimodal ultrasonic flow imaging in Thyroid Imaging Reporting and Data System (TI-RADS) 4 nodules

Abstract

Background: Color Doppler imaging (CDFI), contrast-enhanced ultrasound (CEUS), and superb microvascular imaging (SMI) are used to observe blood flow characteristics in Thyroid Imaging Reporting and Data System (TI-RADS) 4 nodules. The ability of these techniques to distinguish benign from malignant nodules was investigated.Methods: A total of 75 TI-RADS 4 nodules were examined using CDFI, SMI, and CEUS. The blood flow characteristics shown by the three methods were added to the current TI-RADS classification to establish a new TI-RADS classification. The value of the three methods and the diagnostic accuracy of the new and old TI-RADS classification were compared.Results: SMI better captured type II flow in benign nodules and type III flow in malignant nodules relative to CDFI. Malignant nodules detected with CEUS manifested mainly with hypo-enhancement, whereas benign nodules showed iso-and hyper-enhancement. The areas under the receiver operating characteristic (ROC) curves (AUC) obtained through the aforementioned flow distribution models were 0.690 (CDFI), 0.840 (SMI), 0.910 (CEUS), and 0.903 (CEUS and SMI combined mode), respectively. The diagnostic value of CEUS was the highest. Joint inspection using SMI with CEUS showed certain advantages in sensitivity, although the overall accuracy was equal to that of CEUS alone. Except for CDFI, the AUC of the new TI-RADS classification was significantly higher than that of the old one. Perforating vessels and low enhancement were independent predictors of thyroid carcinoma.Conclusions: Both SMI and CEUS visualized lower-velocity blood flow within TI-RADS 4 nodules. The new TI-RADS classification described here could improve diagnostic accuracy.

Contrast-Enhanced Ultrasound in the Differential Diagnosis and Risk Stratification of ACR TI-RADS Category 4 and 5 Thyroid Nodules With Non-Hypovascular

“…Hypo-enhancement on CEUS is considered the most precise predictor of malignancy for thyroid nodules with high sensitivity, specificity, and accuracy of 82%, 85%, and 84%, respectively ( 5 ). While iso-/hyper-enhancement on CEUS can suggest benignity ( 16 , 17 ). However, in our clinical practice, one-third of nodules with American College of Radiology’s Thyroid imaging reporting and data system (ACR TI-RADS) ( 18 ) category 4 and 5 on conventional US appear iso-/hyper-enhancement on CEUS (we defined as “non-hypovascular thyroid nodules”) that turn out to be malignant.…”

Risk Stratification of Thyroid Nodules: From Ultrasound Features to TIRADS

“…Some reports have shown that malignant nodules had mainly hypo-enhancement [62][63][64][65][66], which can be due to fibrosis and neovascular damage by tumor cells, while benign nodules had hyper-enhancement or iso-enhancement, similar to normal tissue. Zang et al reported a higher sensitivity and lower specificity of CEUS + SMI in 75 suspicious nodules, compared with CEUS or SMI alone [67].…”

Multimodal ultrasound imaging: A method to improve the accuracy of diagnosing thyroid TI‐RADS 4 nodules

“…74 Zhang et al 75 found that the combination of TI-RADS and CEUS can significantly improve the diagnostic accuracy of thyroid nodules, especially TI-RADS 4 nodules. Zhang et al 68 studied the thyroid TI-RADS 4 nodules and found that SMI can better capture type II blood flow in benign nodules and type III blood flow in malignant nodules than CDFI. While CEU has the highest diagnostic value, the joint examination using SMI and CEU shows some advantages in sensitivity, although the overall accuracy is the same as that of CEU alone.…”

“…Huang et al 77 68 The results showed that the combination of twodimensional ultrasound TI-RADS and SMI or CEU could improve the diagnostic accuracy, and the diagnostic efficiency of the three combined diagnosis was further improved.…”