Friedrich Degenhardt

Significant Differentiation of Focal Breast Lesions: Calculation of Strain Ratio in Breast Sonoelastography

RATIONALE AND OBJECTIVES Initial data suggest that elastography can improve the specificity of ultrasound in differentiating benign and malignant breast lesions. The aim of this study was to compare elastography and B-mode ultrasound to determine whether the calculation of strain ratios (SRs) can further improve the differentiation of focal breast lesions. MATERIALS AND METHODS A total of 227 women with histologically proven focal breast lesions (113 benign, 114 malignant) were included at two German breast centers. The women underwent a standardized ultrasound procedure using a high-end ultrasound system with a 9-MHz broadband linear transducer. B-mode scans and sonoelastograms were analyzed by two experienced readers using the Breast Imaging Reporting and Data System criteria. SRs were calculated from a tumor-adjusted region of interest (mean color pixel density) and a comparable region of interest placed in the lateral fatty tissue. Sensitivity, specificity, and cutoff values were calculated for SRs (receiver-operating characteristic analysis). RESULTS The women had a mean age of 54 years (range, 19-87 years). The mean lesion diameter was 1.6 +/- 0.9 cm. Sensitivity and specificity were 96% and 56% for B-mode scanning, 81% and 89% for elastography, and 90% and 89% for SRs. An SR cutoff value of 2.45 (area under the curve, 0.949) allowed significant differentiation (P < .001) of malignant (mean, 5.1 +/- 4.2) and benign (mean, 1.6 +/- 1.0) lesions. The quantitative method of SR calculation was superior to subjective interpretation of sonoelastograms and B-mode scans, with a positive predictive value of 89% compared to 68% and 84% for the other two methods. CONCLUSIONS Calculation of SRs contributes to the standardization of sonoelastography with high sensitivity and allows significant differentiation of benign and malignant breast lesions with higher specificity compared to B-mode ultrasound but not elastography.

Multicenter study of ultrasound real-time tissue elastography in 779 cases for the assessment of breast lesions: improved diagnostic performance by combining the BI-RADS®-US classification system with sonoelastography.

PURPOSE Hitachi real-time tissue elastography (HI-RTE) is an ultrasound technique that facilitates the estimation of tissue elasticity. Our study evaluates whether sonoelastography improves the differentiation of benign and malignant breast lesions. MATERIALS AND METHODS In a multicenter approach sonoelastography of focal breast lesions was carried out in 779 patients with subsequent histological confirmation. We present data from 3 study centers (Berlin, Bielefeld, Homburg/Saar) focusing on the sensitivity (SE), specificity (SP) and the positive (PPV) and negative predictive value (NPV) of sonoelastography. In addition we performed an analysis of the diagnostic performance, expressed by the pretest and posttest probability of disease (POD), in BI-RADS®-US 3 or 4 lesions as these categories can imply both malignant and benign lesions and a more precise prediction would be a preferable aim. RESULTS Sonoelastography demonstrated an improved SP (89.5 %) and an excellent PPV (86.8 %) compared to B-mode ultrasound (76.1 % and 77.2 %). Especially in dense breasts ACR III-IV, the SP was even higher (92.8 %). In BI-RADS-US 3 lesions, a suspicious elastogram significantly modified the POD from 8.3 % to a posttest POD of 45.5 %. In BI-RADS-US 4 lesions, we found a pretest POD of 56.6 %. The posttest POD changed significantly to 24.2 % with a normal elastogram and to 81.5 % with a suspicious elastogram. CONCLUSION Our data demonstrates that the complementary use of sonoelastography definitely improves the performance in breast diagnostics. Finally we present a protocol of how sonoelastography can be integrated into our daily practice.

The Automated Breast Volume Scanner (ABVS): initial experiences in lesion detection compared with conventional handheld B-mode ultrasound: a pilot study of 50 cases

The idea of an automated whole breast ultrasound was developed three decades ago. We present our initial experiences with the latest technical advance in this technique, the automated breast volume scanner (ABVS) ACUSON S2000™. Volume data sets were collected from 50 patients and a database containing 23 women with no detectable lesions in conventional ultrasound (BI-RADS®-US 1), 13 women with clearly benign lesions (BI-RADS®-US 2), and 14 women with known breast cancer (BI-RADS®-US 5) was created. An independent examiner evaluated the ABVS data on a separate workstation without any prior knowledge of the patients’ histories. The diagnostic accuracy for the experimental ABVS was 66.0% (95% confidence interval [CI]: 52.9–79.1). The independent examiner detected all breast cancers in the volume data resulting in a calculated sensitivity of 100% in the described setting (95% CI: 73.2%–100%). After the ABVS examination, there were a high number of requests for second-look ultrasounds in 47% (95% CI: 30.9–63.5) of the healthy women (with either a clearly benign lesion or no breast lesions at all in conventional handheld ultrasound). Therefore, the specificity remained at 52.8% (95% CI: 35.7–69.2). When comparing the concordance of the ABVS with the gold standard (conventional handheld ultrasound), Cohen’s Kappa value as an estimation of the inter-rater reliability was κ = 0.37, indicating fair agreement. In conclusion, the ABVS must still be regarded as an experimental technique for breast ultrasound, which definitely needs to undergo further evaluation studies.

Sonographic Features of Triple-Negative and Non–Triple-Negative Breast Cancer

Triple‐negative breast cancer (TNBC) is known to have unique molecular, clinical, and pathologic characteristics. The growth pattern of this cancer may also affect its appearance on sonography. Our study evaluated the sonographic features of TNBC according to the American College of Radiology Breast Imaging Reporting and Data System sonographic classification system and compared these features with those of non‐TNBC.

Diagnostische Aussagekraft der Strain-Ratio-Messung zur Unterscheidung zwischen malignen und benignen Brusttumoren

PURPOSE The aim of this study was to evaluate the strain ratio measurement of breast lesions, to calculate the diagnostic value and to provide practically oriented recommendations concerning execution. MATERIALS AND METHODS 117 breast lesions in 98 patients were included in the study. All lesions were examined by B-mode ultrasound and elastography using strain ratio measurement. The preinterventional findings of the different methods were compared to the final histopathological results. The sensitivity, specificity, positive and negative predictive value and the diagnostic accuracy were calculated for each method. RESULTS There was a significant difference between the strain ratio of malignant (mean 6.50; sd 3.03; 95 %-CI 5.68 - 7.33) and benign (mean 1.79; sd 3.83; 95 %-CI 0.92 - 2.75) lesions. The strain ratio showed a sensitivity of 92.6 % (95 %-CI 82.1 - 97.9) and a specificity of 95.2 % (95 %-CI 86.7 - 99.0). The positive and negative predictive values were 94.3 % and 93.7 %. B-mode ultrasound achieved a sensitivity of 94.4 % (95 %-CI 84.6 - 98.8) and a specificity of 87.3 % (95 %-CI 76.5 - 94.3). The positive and negative predictive values were 86.4 % and 94.8 %. CONCLUSION Strain ratio measurement of breast lesions is a standardized fast method for analyzing the stiffness inside the examined areas. Used as an additional tool to B-mode ultrasound, it helps to increase the specificity of the examination.

Diagnostic performance and inter-observer concordance in lesion detection with the automated breast volume scanner (ABVS)

BackgroundAutomated whole breast ultrasound scanners of the latest generation have reached a level of comfortable application and high quality volume acquisition. Nevertheless, there is a lack of data concerning this technology. We investigated the diagnostic performance and inter-observer concordance of the Automated Breast Volume Scanner (ABVS) ACUSON S2000™ and questioned its implications in breast cancer diagnostics.MethodsWe collected 100 volume data sets and created a database containing 52 scans with no detectable lesions in conventional ultrasound (BI-RADS®-US 1), 30 scans with benign lesions (BI-RADS®-US 2) and 18 scans with breast cancer (BI-RADS®-US 5).Two independent examiners evaluated the ABVS data on a separate workstation without any prior knowledge of the patients’ histories.ResultsThe inter-rater reliability reached fair agreement (κ=0.36; 95% confidence interval (CI): 0.19-0.53). With respect to the true category, the conditional inter-rater validity coefficient was κ=0.18 (95% CI: 0.00-0.26) for the benign cases and κ=0.80 (95% CI: 0.61-1.00) for the malignant cases.Combining the assessments of examiner 1 and examiner 2, the diagnostic accuracy (AC), sensitivity (SE) and specificity (SP) for the experimental ABVS were AC = 79.0% (95% CI: 67.3-86.1), SE = 83.3% (95% CI: 57.7-95.6) and SP = 78.1% (% CI: 67.3-86.1), respectively.However, after the ABVS examination, there were a high number of requests for second-look ultrasounds in up to 48.8% of the healthy women due to assumed suspicious findings in the volume data.In an exploratory analysis, we estimated that an ABVS examination in addition to mammography alone could detect a relevant number of previously occult breast cancers (about 1 cancer in 300 screened and otherwise healthy women).ConclusionsThe ABVS is a reliable imaging method for the evaluation of the breast with high sensitivity and a fair inter-observer concordance. However, we have to overcome the problem of the high number of false-positive results. Therefore, further prospective studies in larger collectives are necessary to define standard procedures in image acquisition and interpretation. Nevertheless, we consider the ABVS as being suitable for integration into breast diagnostics as a beneficial and reliable imaging method.

Ultrasound real-time elastography can predict malignancy in BI-RADS®-US 3 lesions

BackgroundLesions of the breast that are classified BI-RADS®-US 3 by ultrasound are probably benign and observation is recommended, although malignancy may occasionally occur.In our study, we focus exclusively on BI-RADS®-US 3 lesions and hypothesize that sonoelastography as an adjunct to conventional ultrasound can identify a high-risk-group and a low-risk-group within these patients.MethodsA group of 177 breast lesions that were classified BI-RADS®-US 3 were additionally examined with real-time sonoelastography. Elastograms were evaluated according to the Tsukuba Elasticity Score. Pretest and posttest probability of disease (POD), sensitivity (SE), specificity (SP), positive (PPV) and negative predictive values (NPV) and likelihood-ratios (LR) were calculated. Furthermore, we analyzed the false-negative and false-positive cases and performed a model calculation to determine how elastography could affect the proceedings in population screening.ResultsIn our collection of BI-RADS®-US 3 cases there were 169 benign and eight malignant lesions. The pretest POD was 4.5% (95% confidence interval (CI): 2.1–9.0). In patients with a suspicious elastogram (high-risk group), the posttest POD was significantly higher (13.2%, p = 0.041) and the positive LR was 3.2 (95% CI: 1.7–5.9). With a benign elastogram (low-risk group), the posttest POD decreased to 2.2%. SE, SP, PPV and NPV for sonoelastography in BI-RADS®-US 3 lesions were 62.5% (95% CI: 25.9–89.8), 80.5% (95% CI: 73.5–86.0), 13.2% (95% CI: 5.0–28.9) and 97.8% (95% CI: 93.3–99.4), respectively.ConclusionsSonoelastography yields additional diagnostic information in the evaluation of BI-RADS®-US 3 lesions of the breast. The examiner can identify a low-risk group that can be vigilantly observed and a high-risk group that should receive immediate biopsy due to an elevated breast cancer risk.

Acoustic radiation force impulse imaging with Virtual Touch™ tissue quantification: mean shear wave velocity of malignant and benign breast masses.

Acoustic radiation force impulse imaging (ARFI) with Virtual Touch™ tissue quantification (VTTQ) enables the determination of shear wave velocity (SWV) in meters per second (m/s). The aim of our study was to describe the mean SWV in normal breast tissue and various breast masses. We performed measurements of SWV with ARFI VTTQ in 145 breast masses (57 malignant, 88 benign) and in the adjacent breast parenchyma and adipose tissue. The mean SWV as well as the rate of successful measurements were analyzed. The difference between adipose tissue and parenchyma was statistically significant (3.05 versus 3.65 m/s) (P < 0.001). Focusing on breast masses, numerous measurements exceeded the upper limit of possible measurement (≥9.10 m/s, indicated as “X.XX m/s”). Nevertheless, the difference between the malignant and benign masses was statistically significant (8.38 ± 1.99 m/s versus 5.39 ± 2.95 m/s) (P < 0.001). The best diagnostic accuracy (75.9%) was achieved when the cutoff point for malignancy was set to 9.10 m/s in ARFI VTTQ. This implies that the SWV was regarded as suspicious when the upper limit of possible measurement was exceeded and the machine returned the value X.XX m/s. In conclusion, ARFI VTTQ is a feasible method for measurement of SWV in a region of interest. Furthermore, we propose the event of a highly elevated SWV as a significant criterion for malignancy. However, the method is technically not yet fully developed, and the problem of unsuccessful measurements must still be solved.

Acoustic radiation force impulse imaging with virtual touch tissue quantification: measurements of normal breast tissue and dependence on the degree of pre-compression.

Acoustic radiation force impulse imaging (ARFI) with Virtual Touch tissue quantification (VTTQ) enables the determination of shear wave velocity in meters per second (m/s). We investigated shear wave velocity in normal breast tissue and analyzed the influence of the degree of pre-compression on the measurements. In repeated measurements and with normal pre-compression, the mean shear wave velocity in breast parenchyma was significantly higher than that in breast adipose tissue (3.33 ± 1.18 m/s vs. 2.90 ± 1.10 m/s; p < 0.001; 712 measurements in 89 patients). Furthermore, we found a significant positive correlation between degree of pre-compression and velocity measurements. Shear wave velocities with low, moderate and high pre-compression were 1.89, 3.18 and 4.39 m/s in parenchyma, compared with 1.46, 2.55 and 3.64 m/s in adipose tissue, respectively (p < 0.001; 360 measurements in 60 patients). VTTQ of breast tissue is a feasible method with high accuracy; however, the degree of pre-compression applied may significantly influence the measurements.

Variations in the Elasticity of Breast Tissue During the Menstrual Cycle Determined by Real-time Sonoelastography

The purpose of this study was to determine the dependence of breast tissue elasticity on the menstrual cycle of healthy volunteers by means of real‐time sonoelastography.