Sonoelastographic strain ratio: how does the position of reference fat influence it?

PURPOSE: The purpose of this study was to evaluate how the reference fat position influenced the calculation of the sonoelastographic strain ratio. METHODS: Three hundred fifty-eight breast masses (256 benign lesions and 102 malignant lesions) in 300 women (mean age 47.4 years; age range 17-82 years) who had been scheduled for a percutaneous needle biopsy or surgical excision were examined using B-mode ultrasonography and elastography. The sonoelastographic strain ratio was calculated twice per lesion; once by dividing the strain value of the fat near the mass by that of the mass (FLR 1) and once by dividing the strain value of the subcutaneous fat by that of the mass (FLR 2). RESULTS: Most (91.9 %) showed a difference of less than 0.5 between FLR 1 and FLR 2 values. Regardless of the position of reference fat, there was no statistically significant difference between the FLR 1 and FLR 2 values (p value = 0.077 and 0.0825, respectively). According to the pathology of the lesion, a difference between FLR 1 and FLR 2 less than 0.5 occurred in 95.3 % of the benign lesions and 84 % of the malignant lesions (p < 0.001). CONCLUSIONS: The sonoelastographic strain ratio was not significantly affected by the position of reference fat.

Interobserver variability of ultrasound elastography and the ultrasound BI-RADS lexicon of breast lesions.

BACKGROUND: Elastographpy is a newly developed noninvasive imaging technique that uses ultrasound (US) to evaluate tissue stiffness. The interpretation of the same elastographic images may be variable according to reviewers. Because breast lesions are usually reported according to American College of Radiology Breast Imaging and Data System (ACR BI-RADS) lexicons and final category, we tried to compare observer variability between lexicons and final categorization of US BI-RADS and the elasticity score of US elastography. METHODS: From April 2009 to February 2010, 1356 breast lesions in 1330 patients underwent ultrasound-guided core biopsy. Among them, 63 breast lesions in 55 patients (mean age, 45.7 years; range, 21-79 years) underwent both conventional ultrasound and elastography and were included in this study. Two radiologists independently performed conventional ultrasound and elastography, and another three observers reviewed conventional ultrasound images and elastography videos. Observers independently recorded the elasticity score for a 5-point scoring system proposed by Itoh et al., BI-RADS lexicons and final category using ultrasound BI-RADS. The histopathologic results were obtained and used as the reference standard. Interobserver variability was evaluated. RESULTS: Of the 63 lesions, 42 (66.7 %) were benign, and 21 (33.3 %) were malignant. The highest value of concordance among all variables was achieved for the elasticity score (k = 0.59), followed by shape (k = 0.54), final category (k = 0.48), posterior acoustic features (k = 0.44), echogenecity and orientation (k = 0.43). The least concordances were margin (k = 0.26), lesion boundary (k = 0.29) and calcification (k = 0.3). CONCLUSION: Elasticity score showed a higher level of interobserver agreement for the diagnosis of breast lesions than BI-RADS lexicons and final category.

Detection of breast cancer in asymptomatic and symptomatic groups using computer-aided detection with full-field digital mammography.

PURPOSE: We aimed to determine the sensitivity of computer-aided detection (CAD) applied to digital mammography in asymptomatic and symptomatic breast cancer patients. METHODS: We retrospectively analyzed digital mammography and CAD images from 210 patients diagnosed with breast cancer. The patients were divided into symptomatic and asymptomatic groups. The sensitivity of CAD in both groups was assessed in relation to breast tissue density, histopathological type of breast cancer, and tumor size. RESULTS: The detection rate of the CAD system was 87.8% in the asymptomatic group. The sensitivity in different tissue densities was 100% in fatty breasts (P1), 88.9% with scattered fibroglandular densities (P2), 94.4% in heterogeneously dense breasts (P3), and 66.7% in extremely dense breasts (P4). The detection rate of the CAD system in the symptomatic group was 87.2%, and the sensitivity was 90.5%, 90%, 86.6%, and 75% in P1-P4 breasts, respectively. In the asymptomatic group, the CAD system detected 90.3% of invasive ductal carcinomas, not otherwise specified (IDC-NOS) and 88.9% of ductal carcinomas in situ (DCIS), but did not detect other types of malignancy. In the symptomatic group, the CAD system detected 88.2% of IDC-NOS, 88.9% of DCIS and 75% of other types of malignancy. When analyzed according to tumor size, the sensitivity of CAD in the asymptomatic and symptomatic groups was 82.6% and 83.3% for tumors <1 cm, 76.5% and 82.4% for tumors between 1 and 2 cm, and 91.7% and 89% in tumors >2 cm. CONCLUSION: The sensitivity of CAD was low in P4 breasts and high for tumors larger than 2 cm, with no statistically significant differences between the asymptomatic and symptomatic groups for IDC-NOS and DCIS. CAD showed greater sensitivity for other neoplasms in symptomatic patients.