US-Elastography for Breast Lesion Characterization: Prospective Comparison of US BIRADS, Strain Elastography and Shear wave Elastography.

PURPOSE: To evaluate the diagnostic performance of strain elastography (SE) and 2 D shear wave elastography (SWE) and SE/SWE combination in comparison with conventional multiparametric ultrasound (US) with respect to improving BI-RADS classification results and differentiating benign and malignant breast lesions using a qualitative and quantitative assessment. MATERIALS AND METHODS: In this prospective study, 130 histologically proven breast masses were evaluated with baseline US, color Doppler ultrasound (CDUS), SE and SWE (Toshiba Aplio 500 with a 7-15 MHz wide-band linear transducer). Each lesion was classified according to the BIRADS lexicon by evaluating the size, the B-mode and color Doppler features, the SE qualitative (point color scale) and SE semi-quantitative (strain ratio) methods, and quantitative SWE. Histological results were compared with BIRADS, strain ratio (SR) and shear wave elastography (SWE) all performed by one investigator blinded to the clinical examination and mammographic results at the time of the US examination. The area under the ROC curve (AUC) was calculated to evaluate the diagnostic performance of B-mode US, SE, SWE, and their combination. RESULTS: Histological examination revealed 47 benign and 83 malignant breast lesions. The accuracy of SR was statistically significantly higher than SWE (sensitivity, specificity and AUC were 89.2 %, 76.6 % and 0.83 for SR and 72.3 %, 66.0 % and 0.69 for SWE, respectively, p = 0.003) but not higher than B-mode US (B-mode US sensitivity, specificity and AUC were 85.5 %, 78.8 %, 0.821, respectively, p = 1.000). CONCLUSION: Our experience suggests that conventional US in combination with both SE and SWE is a valid tool that can be useful in the clinical setting, can improve BIRADS category assessment and may help in the differentiation of benign from malignant breast lesions, with SE having higher accuracy than SWE.

Can strain US-elastography with strain ratio (SRE) improve the diagnostic accuracy in the assessment of breast lesions? Preliminary results.

PURPOSE: To assess the diagnostic value of strain ratio elastography (SRE), a semiquantitative elastosonographic method based on the displacement of the tissue from an external source (manual compression with the transducer), as compared and in combination with conventional ultrasound for the differentiation of breast lesions. METHODS: One hundred and eighty-two patients with breast lesions consecutively underwent B-mode, color Doppler US, and strain US-elastography. Each lesion was classified according to the BI-RADS lexicon by evaluating the size, the B-mode, and color Doppler features and then evaluated by SRE. Histology proven by biopsy was used as the gold standard and the patients with malignant lesions subsequently underwent operations. The diagnostic performance of each method was assessed with 2 × 2 contingency tables and ROC curve analysis. To maximize the SRE sensitivity and specificity, the SRE cut-off value was calculated using the Youden test. RESULTS: Histological examination revealed 66 benign and 116 malignant breast lesions. The conventional ultrasound showed sensitivity and specificity for the differentiation of benign and malignant lesions of 86.2% and 75.8%, respectively. Similar results were found for strain US-elastography with a cut-off of 2.49, with sensitivity and specificity of 89.7% and 72.7%, respectively. The association of conventional ultrasound with the SRE value increased the sensitivity (98.3%) but decreased the specificity compared with conventional US alone (63.6%). CONCLUSION: Strain US-elastography can be associated with BI-RADS US examination. According to our preliminary results, it helped increase the sensitivity although it decreased the specificity. However, further multicenter studies on a larger population are warranted.

Breast lesion detection and characterization at contrast-enhanced MR mammography: gadobenate dimeglumine versus gadopentetate dimeglumine.

PURPOSE: To prospectively and intraindividually compare equivalent (0.1 mmol per kilogram of body weight) doses of gadobenate dimeglumine and gadopentetate dimeglumine for accuracy of detection and characterization of breast lesions at contrast material-enhanced magnetic resonance (MR) mammography. MATERIALS AND METHODS: Ethics committee approval and informed consent were obtained. Twenty-six consecutive women (mean age, 47.8 years) suspected of having a breast tumor at mammography and sonography underwent two identical MR examinations at 1.5 T; examinations were separated by more than 48 hours but less than 72 hours. A T1-weighted three-dimensional gradient-echo sequence was used, and images were acquired before and at 0, 2, 4, 6, and 8 minutes after randomized injection of gadopentetate dimeglumine or gadobenate dimeglumine at an identical flow rate of 2 mL/sec. Separate and combined assessment of unenhanced, contrast-enhanced, and subtracted images was performed blindly by two readers in consensus. Accuracy for lesion detection was determined against a final diagnosis based on findings at conventional mammography, sonography, and surgery. Sensitivity, specificity, positive and negative predictive values, and overall accuracy for malignant lesion identification were determined against histologic results. Data were analyzed with the McNemar test, proportional odds models, and analysis of variance. RESULTS: MR mammography with gadobenate dimeglumine depicted significantly (P = .003) more lesions (45 of 46) than did that with gadopentetate dimeglumine (36 of 46), and detected lesions were significantly (P < .001) more conspicuous with gadobenate dimeglumine. Confidence for characterization was significantly (P = .031) greater with gadobenate dimeglumine. Comparison of the contrast agents for their ability to help identify malignant lesions revealed significant (P = .02) superiority for gadobenate dimeglumine: Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy for malignant lesion identification were, respectively, 94.7%, 100%, 100%, 80.0%, and 95.6% with gadobenate dimeglumine and 76.3%, 100%, 100%, 47.1%, and 80.4% with gadopentetate dimeglumine. Quantitative evaluation of signal intensity-time curves revealed significantly (P < .001) greater lesion enhancement with gadobenate dimeglumine. CONCLUSION: Detection of breast lesions and accurate identification of malignant lesions at MR imaging are significantly superior with gadobenate dimeglumine in comparison with gadopentetate dimeglumine.

Radial scars of the breast: contrast-enhanced magnetic resonance mammography appearance.

The purpose of this study was to evaluate the appearance of contrast-enhanced magnetic resonance mammography (CE-MRM) in patients with suspected radial scar on mammography. Thirty women with radial opacities or black star findings at mammography, preoperatively underwent CE-MRM. Examinations were performed with a 1.5 T magnet with a bilateral surface coil using a FS T2-weighted turbo spin echo (TSE) and three-dimensional (3D) dynamic T1-weighted fast low-angle shot (FLASH) sequences. Criteria for lesion evaluation included morphologic patterns and signal intensity curves. Mammography and CE-MRM findings were compared with pathologic findings. CE-MRM suggested the presence of radial scar in 18 of 30 cases and the presence of malignancy in 11 of 30 cases; 1 lesion was classified as borderline. At surgery 22 radial scars (including 4 with associated ductal carcinoma in situ) and 8 carcinomas were detected. CE-MRM provided a specificity of 89%, sensitivity of 83%, and accuracy of 87%. Differently from breast cancer, radial scars are nonenhancing at CE-MRM. Nevertheless, the possibility of nonenhancing carcinomatous foci existing within radial scars implies that surgical excision should be performed in all cases.