Typical contrast-enhanced ultrasonographic findings of malignant breast tumors (JABTS FLOW-CEUS01 study -part 4-)

Abstract

Background and Objectives In a multi-center study (JABTS FLOW-CEUS01, UMINID: 000026289), the Flow Imaging Research Group, the Japan Association of Breast and Thyroid Sonology (JABTS) evaluated the difference of contrast-enhanced patterns between benign and malignant breast tumors by contrast-enhanced ultrasonography (CEUS). The purpose of this study was to select and present typical CEUS images of malignant breast tumors from the results of a multi-center study. Methods CEUS was performed by using the ultrasound contrast agent perflubutane (Sonazoid®); the ultrasound scanners were equipped with a high-frequency linear transducer. In this study, a total of 188 tumors (malignant: 148, benign: 40) were evaluated by three blind readers. This study was approved by the Ethics Committee and Institutional Review Board of Hokkaido University Hospital. Results One hundred and fourteen tumors of the 148 malignant tumors (77.0%) were correctly diagnosed by three blind readers as malignant. Of these 114 tumors, we present typical cases in which there was high consensus on the findings. Case Presentation Case 1 (Invasive carcinoma of no special type (NST)): B-mode ultrasonography (US) image showed microlobulated margin and hypoechoic pattern with parallel orientation. CEUS image showed irregular margin and strong enhancement, with clear internal defect. Case 2 (Invasive carcinoma of NST): B-mode US image showed irregular shape, hypoechoic pattern, and a thick rim. CEUS image showed irregular shape, irregular margin, and strong heterogeneous enhancement, with wider range than those of the B-mode US image. Case 3 (Invasive carcinoma of NST): B-mode US image showed hypoechoic mass with angular margin. CEUS image showed irregular shape, irregular margin, and strong homogeneous enhancement, with wider range than those of the B-mode US image. Case 4 (Invasive lobular carcinoma): B-mode US image showed irregular shape and hypoechoic pattern with a thick rim. CEUS image showed irregular shape, strong heterogeneous enhancement with wider range than those of the B-mode US image and plunging or penetrating vessels. Case 5 (Ductal carcinoma in situ): B-mode US image showed irregular shape and hypoechoic pattern with parallel orientation. CEUS showed irregular shape and strong heterogeneous enhancement with wider range than those of the B-mode US image. Conclusions We clarified that the typical CEUS images of malignant breast tumors, were irregular enhancement, and a wider enhancement range than those of B-mode US. Another suggested finding associated with malignancy was plunging or penetrating vessels.