BI-RADS 4 breast lesions: could multi-mode ultrasound be helpful for their diagnosis?

Abstract

Background: The malignant probability of Breast Imaging Reporting and Data System (BI-RADS) 4 breast lesions is 3-94%, which is a very large span, and thus leads to a high rate of unnecessary biopsy. Therefore, the differential diagnosis of benign and malignant BI-RADS 4 breast lesions has become extremely important. Thus, in this paper, we investigated the diagnostic value of conventional ultrasonography (US), contrast-enhanced ultrasound (CEUS) and shear wave elastography (SWE) for BI-RADS 4 breast lesions, and tried to figure out a multi-mode ultrasonic method for them.

Methods: From March 2016 to May 2017, 118 breast lesions that were categorized as BI-RADS 4 lesions by US were studied with CEUS and SWE. All the lesions were confirmed by pathology via surgery or vacuum-assisted biopsy. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of US, CEUS and SWE were analyzed. Then the diagnostic efficacies of US, CEUS, SWE and the combination of these modalities were compared. Logistic regression analysis was performed to identify the independent risk factors. A multi-mode method to evaluate BI-RADS 4 lesions based on the logistic regression was developed.

Results: Of the 118 BI-RADS 4 lesions, 74 lesions (62.7%) were benign and 44 lesions (37.3%) were malignant. The diagnostic sensitivity and specificity for US, US + CEUS, US + SWE, US + CEUS + SWE were 88.6% and 75.7%, 86.4% and 94.6%, 88.6% and 90.5%, 97.7% and 93.2%, respectively. The area under the ROC curve (AUC) of US + SWE + CEUS was significantly higher than that of US (P<0.0001), US + CEUS (P=0.020), but there was no significant difference between the AUC of US + SWE + CEUS and the AUC of US + SWE.

Conclusions: US + CEUS + SWE and US + SWE could significantly improve the diagnostic efficiency and accuracy of US in the diagnosis of BI-RADS 4 breast lesions.

Keywords: Breast Imaging Reporting and Data System (BI-RADS); Contrast-enhanced ultrasound (CEUS); breast lesions; shear wave elastography (SWE).

Figure 1

CEUS image of a 53-year-old female. Heterogeneous hyperechoic enhancement could be seen on CEUS image, with enhanced area enlargement (the red oval) and the radial or penetrating vessels (the red arrow) surround the lesion. CEUS, contrast-enhanced ultrasound.

Figure 2

CEUS image of an invasive ductal carcinoma. The time-intensity curve (the red line) of the lesion (the red box) showed a fast-in and fast-out pattern with short arrival time, short time to peak and high peak intensity compared with that (the yellow line) of normal breast tissue (the yellow box). CEUS, contrast-enhanced ultrasound.

Figure 3

SWE image of an invasive carcinoma. The lesion showed a “stiff rim sign”. SWE, shear wave elastography.

Figure 4

ROC curves of the maximum elasticity, mean elasticity, minimum elasticity, ratio and stiff rim sign; the ratio has a higher AUC. Our results indicated that the AUC of ratio was significantly higher than that of minimum elasticity and mean elasticity, and the AUC of Ratio was also higher than that of maximum elasticity and stiff rim sign, but there was no statistical significance. AUC, area under the ROC curve.

Figure 5

ROC curves of US, US + CEUS, US + SWE, US + SWE + CEUS, US + stiff rim sign, US + maximum elasticity; US + SWE+CEUS has a higher AUC. Our results indicated that the AUC of US + SWE + CEUS was significantly higher than that of US, US + CEUS, US + SWE + CEUS, US + stiff rim sign, US + maximum elasticity, and the AUC of ratio was also higher than that of US + SWE, but there was no statistical significance. US, ultrasonography; CEUS, contrast-enhanced ultrasound; SWE, shear wave elastography; AUC, area under the ROC curve.