Sebastian Wojcinski

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.

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.

Real-time ultrasound elastography in 180 axillary lymph nodes: elasticity distribution in healthy lymph nodes and prediction of breast cancer metastases

BackgroundTo determine the general appearance of normal axillary lymph nodes (LNs) in real-time tissue sonoelastography and to explore the method′s potential value in the prediction of LN metastases.MethodsAxillary LNs in healthy probands (n=165) and metastatic LNs in breast cancer patients (n=15) were examined with palpation, B-mode ultrasound, Doppler and sonoelastography (assessment of the elasticity of the cortex and the medulla). The elasticity distributions were compared and sensitivity (SE) and specificity (SP) were calculated. In an exploratory analysis, positive and negative predictive values (PPV, NPV) were calculated based upon the estimated prevalence of LN metastases in different risk groups.ResultsIn the elastogram, the LN cortex was significantly harder than the medulla in both healthy (p=0.004) and metastatic LNs (p=0.005). Comparing healthy and metastatic LNs, there was no difference in the elasticity distribution of the medulla (p=0.281), but we found a significantly harder cortex in metastatic LNs (p=0.006). The SE of clinical examination, B-mode ultrasound, Doppler ultrasound and sonoelastography was revealed to be 13.3%, 40.0%, 14.3% and 60.0%, respectively, and SP was 88.4%, 96.8%, 95.6% and 79.6%, respectively. The highest SE was achieved by the disjunctive combination of B-mode and elastographic features (cortex >3mm in B-mode or blue cortex in the elastogram, SE=73.3%). The highest SP was achieved by the conjunctive combination of B-mode ultrasound and elastography (cortex >3mm in B-mode and blue cortex in the elastogram, SP=99.3%).ConclusionsSonoelastography is a feasible method to visualize the elasticity distribution of LNs. Moreover, sonoelastography is capable of detecting elasticity differences between the cortex and medulla, and between metastatic and healthy LNs. Therefore, sonoelastography yields additional information about axillary LN status and can improve the PPV, although this method is still experimental.

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.

The biology of malignant breast tumors has an impact on the presentation in ultrasound: an analysis of 315 cases

BackgroundThe aim of this study was to evaluate the relation of some ultrasound morphological parameters to biological characteristics in breast carcinoma.MethodsUltrasound data from 315 breast masses were collected. We analyzed the ultrasound features of the tumors according to the ACR BI-RADS®-US classification system stratified by hormone receptor status, HER2 status, histology grade, tumor type (ductal versus lobular), triple-negativity, breast density, tumor size, lymph node involvement and patient’s age.ResultsWe found a variety of ultrasound features that varied between the groups. Invasive lobular tumors were more likely to have an angulated margin (39% versus 22%, p = 0.040) and less likely to show posterior acoustic enhancement (3% versus 16%, p = 0.023) compared to invasive ductal carcinoma. G3 tumors were linked to a higher chance of posterior acoustic enhancement and less shadowing and the margin of G3 tumors was more often described as lobulated or microlobulated compared to G1/G2 tumors (67% versus 46%, p = 0.001). Tumors with an over-expression of HER2 exhibited a higher rate of architectural distortions in the surrounding tissue, but there were no differences regarding the other features. Hormone receptor negative tumors were more likely to exhibit a lobulated or microlobulated margin (67% versus 50%, p = 0.037) and less likely to have an echogenic halo (39% versus 64%, p = 0.001). Furthermore, the posterior acoustic feature was more often described as enhancement (33% versus 13%, p = 0.001) and less often as shadowing (20% versus 47%, p < 0.001) compared to hormone receptor positive tumors.ConclusionDepending on their biological and clinical profile, breast cancers are more or less likely to exhibit the typical criteria for malignancy in ultrasound. Moreover, certain types of breast cancer tend to possess criteria that are usually associated with benign masses. False-negative diagnosis may result in serious consequences for the patient. For the sonographer it is essential to be well aware of potential variations in the ultrasound morphology of breast tumors, as described in this paper.