A Prospective Study on the Value of Ultrasound Microflow Assessment to Distinguish Malignant from Benign Solid Breast Masses: Association between Ultrasound Parameters and Histologic Microvessel Densities

Abstract

Objective To investigate the value of ultrasound (US) microflow assessment in distinguishing malignant from benign solid breast masses as well as the association between US parameters and histologic microvessel density (MVD). Materials and Methods Ninety-eight breast masses (57 benign and 41 malignant) were examined using Superb Microvascular Imaging (SMI) and contrast-enhanced US (CEUS) before biopsy. Two radiologists evaluated the quantitative and qualitative vascular parameters on SMI (vascular index, morphology, distribution, and penetration) and CEUS (time-intensity curve analysis and enhancement characteristics). US parameters were compared between benign and malignant masses and the diagnostic performance was compared between SMI and CEUS. Subgroup analysis was performed according to lesion size. The effect of vascular parameters on downgrading Breast Imaging Reporting and Data System (BI-RADS) category 4A masses was evaluated. The association between histologic MVD and US parameters was analyzed. Results Malignant masses were associated with a higher vascular index (15.1 ± 7.3 vs. 5.9 ± 5.6), complex vessel morphology (82.9% vs. 42.1%), central vascularity (95.1% vs. 59.6%), penetrating vessels (80.5% vs. 31.6%) on SMI (all, p < 0.001), as well as higher peak intensity (37.1 ± 25.7 vs. 17.0 ± 15.8, p < 0.001), slope (10.6 ± 11.2 vs. 3.9 ± 4.2, p = 0.001), area (1035.7 ± 726.9 vs. 458.2 ± 410.2, p < 0.001), hyperenhancement (95.1% vs. 70.2%, p = 0.005), centripetal enhancement (70.7% vs. 45.6%, p = 0.023), penetrating vessels (65.9% vs. 22.8%, p < 0.001), and perfusion defects (31.7% vs. 3.5%, p < 0.001) on CEUS ( p ≤ 0.023). The areas under the receiver operating characteristic curve (AUCs) of SMI and CEUS were 0.853 and 0.841, respectively ( p = 0.803). In 19 masses measuring < 10 mm, central vascularity on SMI was associated with malignancy (100% vs. 38.5%, p = 0.018). Considering all benign SMI parameters on the BI-RADS assessment, unnecessary biopsies could be avoided in 12 category 4A masses with improved AUCs (0.500 vs. 0.605, p < 0.001). US vascular parameters associated with malignancy showed higher MVD ( p ≤ 0.016). MVD was higher in malignant masses than in benign masses, and malignant masses negative for estrogen receptor or positive for Ki67 had higher MVD ( p < 0.05). Conclusion US microflow assessment using SMI and CEUS is valuable in distinguishing malignant from benign solid breast masses, and US vascular parameters are associated with histologic MVD.

Combination of Quantitative Parameters of Shear Wave Elastography and Superb Microvascular Imaging to Evaluate Breast Masses

“…The optimal cutoff values of the SMIVI varied from 4.0% to 8.9% for differentiating benign and malignant breast masses (25,26). In both studies, an SMI image with the most abundant Doppler signal was retrospectively selected among the previously obtained images and drew the ROI for SMIVI using the postprocessing software masses (25,26). In our study, each observer selected Doppler images and drew the ROI for kjronline.org were less than 10 mm in diameter.…”

“…SMI VI is the percentage ratio between the pixels for the Doppler signal and those for the total lesion ( 23 24 ). Studies investigating the diagnostic value of SMI VI in differentiating benign and malignant breast masses are relatively few ( 25 26 ). However, studies assessing the cutoff values of the quantitative parameters derived from both SWE and SMI and the diagnostic performance of combining these quantitative parameters and B-mode US-based breast imaging reporting and data system (BI-RADS) have not been conducted yet.…”

Diagnostic accuracy of ultrasound superb microvascular imaging for breast tumor: a meta-analysis

“…Of that benign masses tend to display the non-vascular pattern, a linear or curvilinear pattern and a treelike pattern, while malignant masses tend to display the root hair-like pattern and the crab claw-like pattern [12]. Smart 3-D SMI can quantitatively assess tumor vascularity via measuring vascularity index (VI) on 2-D SMI images obtained with the qualitative guidance of 3-D SMI images, which is significantly higher in malignant lesions than that in benign ones and may potentially serve as a noninvasive tool to accurately characterize benign versus malignant breast lesions [20]. Present studies have revealed that SMI is more accurate in the detection and characterization of breast lesions comparable with mammography X-ray and conventional CDFI scanning [15].…”

“…We reviewed the titles and abstracts of all articles and excluded 21 articles; full texts and data integrity were also reviewed and 11 were further excluded. Finally, 15 studies that met all inclusion criteria were included in this meta-analysis [11][12][13][14][15][16][17][18][19][20][21][22][23][24][25]. Figure 1 showed the selection process of eligible articles.…”

<p>The Vascular Index of Superb Microvascular Imaging Can Improve the Diagnostic Accuracy for Breast Imaging Reporting and Data System Category 4 Breast Lesions</p>

“…Compared with BI-RADS, the VI offers improved diagnostic efficiency. Park et al 22 studied the diagnostic efficacy of degradation of BI-RADS 4A lesions with 8.9 as the cutoff value of VI. Twenty-six lesions were downgraded to BI-RADS 3 with improved PPV (56.9% vs 41.8%) and AUC (0.728 vs 0.500, p < 0.001) compared to the original BI-RADS assessment, consistent with our results.…”