Added value of Virtual Touch IQ shear wave elastography in the ultrasound assessment of breast lesions

Purpose

To determine the diagnostic performance of Acoustic Radiation Force Impulse (ARFI) Virtual Touch IQ shear wave elastography in the discrimination of benign and malignant breast lesions.

Materials and methods

Conventional B-mode and elasticity imaging were used to evaluate 110 breast lesions. Elastographic assessment of breast tissue abnormalities was done using a shear wave based technique, Virtual Touch IQ (VTIQ), implemented on a Siemens Acuson S3000 ultrasound machine. Tissue mechanical properties were interpreted as two-dimensional qualitative and quantitative colour maps displaying relative shear wave velocity. Wave speed measurements in m/s were possible at operator defined regions of interest. The pathologic diagnosis was established on samples obtained by ultrasound guided core biopsy or fine needle aspiration.

Results

BIRADS based B-mode evaluation of the 48 benign and 62 malignant lesions achieved 92% sensitivity and 62.5% specificity. Subsequently performed VTIQ elastography relying on visual interpretation of the colour overlay displaying relative shear wave velocities managed similar standalone diagnostic performance with 92% sensitivity and 64.6% specificity. Lesion and surrounding tissue shear wave speed values were calculated and a significant difference was found between the benign and malignant populations (Mann–Whitney U test, p < 0.0001). By selecting a lesion cut-off value of 3.31 m/s we achieved 80.4% sensitivity and 73% specificity. Applying this threshold only to BIRADS 4a masses, we reached overall levels of 92% sensitivity and 72.9% specificity.

Conclusion

VTIQ qualitative and quantitative elastography has the potential to further characterise B-mode detected breast lesions, increasing specificity and reducing the number of unnecessary biopsies.     

Nonpalpable breast masses: evaluation by US elastography.

OBJECTIVE: To compare the diagnostic performances of conventional ultrasound (US) and US elastography for the differentiation of nonpalpable breast masses, and to evaluate whether elastography is helpful at reducing the number of benign biopsies, using histological analysis as a reference standard. MATERIALS AND METHODS: Conventional US and real-time elastographic images were obtained for 100 women who had been scheduled for a US-guided core biopsy of 100 nonpalpable breast masses (83 benign, 17 malignant). Two experienced radiologists unaware of the biopsy and clinical findings analyzed conventional US and elastographic images by consensus, and classified lesions based on degree of suspicion regarding the probability of malignancy. Results were evaluated by receiver operating characteristic curve analysis. In addition, the authors investigated whether a subset of lesions was categorized as suspicious by conventional US, but as benign by elastography. RESULTS: Areas under the ROC curves (Az values) were 0.901 for conventional US and 0.916 for elastography (p = 0.808). For BI-RADS category 4a lesions, 44% (22 of 50) had an elasticity score of 1 and all were found to be benign. CONCLUSION: Elastography was found to have a diagnostic performance comparable to that of conventional US for the differentiation of nonpalpable breast masses. The authors conclude that BI-RADS category 4a lesions with an elasticity score of 1 probably do not require biopsy.     

Elastography of the pancreas

Elastography has recently been presented in clinical studies as a new technique applied to US imaging. The challenge of this new technique is to distinguish different tissues on the basis of their specific consistency. Since malignant tumors tend to be harder than benign lesions and parenchyma, this new approach could result clinically relevant. Initial clinical experiences in US elastography have been promising in differentiating breast, thyroid and prostate nodules. Pancreatic applications of US elastography are relatively recent and under validation with several studies so far published in literature.     

乳腺肿块的超声弹性成像和外科检查的相关性分析

目的:通过对超声弹性成像和外科检查乳腺肿块的方法进行分析,比较这两种检查方法在乳腺良、恶性肿块鉴别诊断中的价值。材料和方法:分别用弹性成像技术和外科触诊检查对61枚乳腺肿块进行良、恶性的鉴别诊断,并与术后的病理结果进行对照。结果:超声弹性成像和外科触诊具有一定的相关性,在鉴别乳腺良、恶性肿块中,超声弹性成像的准确性要高于外科触诊。结论:超声弹性成像技术为超声鉴别诊断良、恶性乳腺肿块提供了一个新的手段,尤其在一些边界不清、形态不规则病灶的良、恶性鉴别诊断上具有较高的临床应用价值。     

Appearence of breast masses on sonoelastography with special focus on the diagnosis of fibroadenomas

The aim of this study was to show and correlate the imaging features of breast masses, especially fibroadenomas, using sonoelastography. Two hundred thirty-five patients with 302 breast lesions referred for core needle biopsy participated in the study. All lesions appearing as solid masses on conventional US were included. Out of the included lesions (270), 115 (42.6%) corresponded to histologically confirmed fibroadenomas and 155 (57.4%) to lesions with histologically confirmed diagnoses other than fibroadenomas. These were further subdivided into fibrocystic changes, lesions with low malignancy potential, and malignant lesions. Fibroadenomas were also divided according to histological presentation into three subgroups to allow comparative study based on elastographic scores. All lesions were classified using a four-point scoring system based on ultrasound elastography imaging characteristics. Different presentations were observed for elastographic scores according to histological presentation of fibroadenomas, whereby fibroadenomas with benign characteristics tended to have elastographic classification similar to fibrocystic changes, and complex and hypercellular fibroadenomas had classifications similar to harder lesions. Fibroadenomas are generally classified as category 3 in the BI-RADS® lexicon and are the most commonly found lesions in breast biopsies. Sonoelastography can provide additional information to conventional studies and be used as an auxiliary tool in assessing these masses in clinical practice.     

乳腺摄影与超声弹性成像对乳腺疾病诊断的对比性研究

目的:评价乳腺摄影、普通超声及超声联合弹性成像技术对乳腺病变的诊断价值。方法:回顾性分析1l6个乳腺病灶(恶性30个、良性86个)的术前乳腺摄影、普通超声及超声联合弹性成像对乳腺疾病的诊断结果,将病变按BI-RADS分类后,分别与病理结果对照分析,计算三种方法诊断的敏感性、特异性、阳性预测值、阴性预测值、准确率,采用McNemar 2检验,评价诊断效果。结果:乳腺摄影、普通超声及超声联合弹性成像诊断的敏感性、特异性、准确率、阳性预测值、阴性预测值分别为:46.67%、95.35%、82.76%、77.78%、83.68%;63.33%、96.51%、87.93%、82.61%、89.25%;86.67%、96.51%、93.97%8、3.87%97.65%。乳腺摄影成像与超声弹性成像诊断结果有统计学差异(P(0.05),普通超声与超声弹性成像诊断结果有统计学差异(P0.05)。结论:超声弹性成像作为超声诊断的辅助模式之一,有助于提高超声乳腺检查的准确性。     

Breast ultrasound elastography—Results of 193 breast lesions in a prospective study with histopathologic correlation

Purpose

To evaluate the diagnostic performance of ultrasound elastography in breast masses.

Material and methods

193 lesions (129 benign, 64 malignant) were analyzed with the EUB 8500 Logos-ultrasonic-unit (Hitachi Medical, Japan) and a linear-array-transducer of 7.5-13-MHz. Standard of reference was cytology (FNAfine needle aspiration) or histology (core biopsy). The elastic-score was classified according to a 6-point colour-scale (Ueno classification; 1-3 = benign, 4-5 = malignant). Conventional B-mode ultrasound (US) findings were classified according to the BI-RADS classification. Statistical analysis included sensitivity, specificity, ROC-analysis and kappa-values for intra-/interobserver reliability.

Results

The mean score for elasticity was 4.1 ± 0.9 for malignant lesions, and 2.1 ± 1.0 for benign lesions (p < 0.001). With a best cut-off point between elasticity scores 3 and 4, sensitivity was 96.9%, and specificity 76%. Setting a best cut-off point for conventional US between BI-RADS 4 and 5, sensitivity was 57.8%, and specificity 96.1%. Elastography provided higher sensitivity and lower specificity than conventional US, but two lesions with elasticity score 1 were false negative, whereas no lesion scored BI-RADS 1-3 were false negative. ROC-curve was 0.884 for elastography, and 0.820 for conventional US (p < 0.001). Weighted kappa-values for intra-/interobserver reliability were 0.784/0.634 for BI-RADS classification, and 0.720/0.561 for elasticity scores.

Conclusion

In our study setting, elastography does not have the potential to replace conventional B-mode US for the detection of breast cancer, but may complement conventional US to improve the diagnostic performance.     

弹性成像对超声引导乳腺肿块穿刺活检指导价值研究

目的探讨超声弹性成像对超声引导BI-RADS 4级乳腺肿块穿刺活检的指导价值。方法回顾性分析141例经超声引导下BI-RADS 4级乳腺肿块穿刺活检患者的临床资料。所有患者穿刺前均进行常规超声及弹性成像检查,以BI-RADS分级及弹性评分评价乳腺肿块的良恶性。结果 BI-RADS分级为4a级的阴性预测值(NPV)为89.6%,弹性评分≤3分的NPV为95.5%,两者比较,差异无统计学意义(P>0.05);BI-RADS分级为4b级的阳性预测值(PPV)为59.3%,弹性评分≥4分的PPV为85.3%,两者比较,差异有统计学意义(P<0.05);BI-RADS分级为4c级的PPV为89.7%,弹性评分≥4分的PPV为96.9%,两者比较,差异无统计学意义(P>0.05);BI-RADS分级≥4b级的PPV为72.0%,弹性评分≥4分的PPV为90.9%,两者比较,差异有统计学意义(P<0.05)。结论弹性评分<3分的4a级乳腺肿块可以短期随访观察;弹性评分为5分的4c级乳腺肿块建议直接手术治疗;对于良恶性难以鉴别的4b级乳腺肿块,超声弹性成像可以进一步提高其PPV,建议穿刺活检明确诊断。     

Diagnostic performance of qualitative shear-wave elastography according to different color map opacities for breast masses

Purpose

To compare the diagnostic performance of qualitative shear-wave elastography (SWE) according to three different color map opacities for breast masses

Materials and methods

101 patients aged 21–77 years with 113 breast masses underwent B-mode US and SWE under three different color map opacities (50%, 19% and 100%) before biopsy or surgery. Following SWE features were reviewed: visual pattern classification (pattern 1–4), color homogeneity (E_homo) and six-point color score of maximum elasticity (E_col). Combined with B-mode US and SWE, the likelihood of malignancy (LOM) was also scored. The area under the curve (AUC) was obtained by ROC curve analysis to assess the diagnostic performance under each color opacity.

Results

A visual color pattern, E_homo, E_col and LOM scoring were significantly different between benign and malignant lesions under all color opacities (P < 0.001). For 50% opacity, AUCs of visual color pattern, E_col, E_homo and LOM scoring were 0.902, 0.951, 0.835 and 0.975. But, for each SWE feature, there was no significant difference in the AUC among three different color opacities. For all color opacities, visual color pattern and E_col showed significantly higher AUC than E_homo. In addition, a combined set of B-mode US and SWE showed significantly higher AUC than SWE alone for color patterns, E_homo, but no significant difference was found in E_col.

Conclusion

Qualitative SWE was useful to differentiate benign from malignant breast lesion under all color opacities. The difference in color map opacity did not significantly influence diagnostic performance of SWE.     

Elastography ultrasound and questionable breast lesions: Does it count?

Objective

To check possible additional value of using elastography ultrasound in the specification of questionable breast lesions.

Subjects and methods

Questionable breast lesions on gray scale ultrasound examination had been further evaluated by elastography ultrasound in 97 cases with median age of 42 years. The studied lesions were pathologically proven (58 benign and 39 malignant) using true cut tissue/surgical excision biopsy that was considered the gold standard of reference.

Results

Conventional ultrasound categorization before biopsy included: category 3 (probably benign) in 42.3% (n = 41), category 4a (low suspicion of malignancy) in 13.4% (n = 13), category 4b (intermediate suspicion of malignancy) in 16.5% (n = 16) and category 4c (moderate suspicion of malignancy) in 27.8% (n = 27). We had evaluated elastography ultrasound regarding elastography strain scoring and quantitative strain ratio.Sensitivity, specificity and accuracy were 89.7%, 86.2% and 87.6% for conventional ultrasound, 92.3%, 74.1% and 81.4% for elastogram 5-point scoring method and 87.1%, 89.6% and 88.6% for the calculated strain ratios respectively in the assessment of the examined breast lesions.

Conclusion

Ultrasound elastography, using both qualitative and quantitative methods can improve the performance of conventional B-mode ultrasound and enhance its specificity and accuracy in the diagnosis of questionable (BI-RADS categories 3 and 4) breast lesions.     

Role of combined grey scale US and US tissue elastography in differentiating solid thyroid nodules

Background

Ultrasonographic (US) examination is an accurate method for detecting thyroid nodules, but its use in differentiating between benign and malignant thyroid nodules is relatively low. US elastography has been applied to study the hardness/elasticity of nodules to differentiate malignant from benign lesions thus deviating a significant group of patients from unnecessary FNAB.

Objectives

The aim of the study is to evaluate the validity of combined grey scale US and tissue elastography in differentiating benign form malignant solid thyroid nodules.

Methods

The study included 46 selected patients with solid thyroid nodules according to our inclusion and exclusion criteria. The patients underwent surgery for compressive symptoms or suspicion of malignancy on FNA cytology. US features and tissue elastography were scored according to the Rago criteria (1).

Results

On US elastography: all the 31 cases with a final diagnosis of benign nodule had a score of 1–3, while 14 of 15 (94.1%) with a final diagnosis of carcinoma had a score of 4–5, with a sensitivity of 93.3%, a specificity of 100% and an accuracy of 97.8%. Combined US and elastography reveals that hypoechogenicity/score 4–5 was most predictive of malignancy with sensitivity 80% and specificity 100%; and accuracy 93.4%.

Conclusions

US elastography seems to have great potential as a new tool for differentiating solid thyroid nodules and for recommending FNAC. Combined grey scale US features and US elastography added no significant value when compared with US elastography alone. Further prospective studies are needed.     

Breast disease: clinical application of US elastography for diagnosis

PURPOSE: To evaluate the diagnostic performance of real-time freehand elastography by using the extended combined autocorrelation method (CAM) to differentiate benign from malignant breast lesions, with pathologic diagnosis as the reference standard. MATERIALS AND METHODS: This study was approved by the University of Tsukuba Human Subjects Institutional Review Board; all patients gave informed consent. Conventional ultrasonography (US) and real-time US elastography with CAM were performed in 111 women (mean age, 49.4 years; age range, 27-91 years) who had breast lesions (59 benign, 52 malignant). Elasticity images were assigned an elasticity score according to the degree and distribution of strain induced by light compression. The area under the curve and cutoff point, both of which were obtained by using a receiver operating characteristic curve analysis, were used to assess diagnostic performance. Mean scores were examined by using a Student t test. Sensitivity, specificity, and accuracy were compared by using the standard proportion difference test or the Delta-equivalent test. RESULTS: For elasticity score, the mean +/- standard deviation was 4.2 +/- 0.9 for malignant lesions and 2.1 +/- 1.0 for benign lesions (P < .001). When a cutoff point of between 3 and 4 was used, elastography had 86.5% sensitivity, 89.8% specificity, and 88.3% accuracy. When a best cutoff point of between 4 and 5 was used, conventional US had 71.2% sensitivity, 96.6% specificity, and 84.7% accuracy. Elastography had higher sensitivity than conventional US (P < .05). By using equivalence bands for noninferiority or equivalence, it was shown that the specificity of elastography was not inferior to that of conventional US and that the accuracy of elastography was equivalent to that of conventional US. CONCLUSION: For assessing breast lesions, US elastography with the proposed imaging classification, which was simple compared with that of the Breast Imaging Recording and Data System classification, had almost the same diagnostic performance as conventional US.     

Value of mammography and combined grey scale ultrasound and ultrasound elastography in the differentiation of solid breast lesions

Aim of the work

The aim of this work was to evaluate the value of ultrasound elastography (UE) in differentiating benign versus malignant solid breast lesions discovered in mammography and compare it with grey scale ultrasound (US) and mammography.

Methods

From May 2011 to May 2013, 114 solid lesions from 100 consecutive patients discovered during mammography were categorized into benign or malignant by mammography and US and further analyzed with UE. The diagnostic results of the cases were compared with histopathologic findings.

Results

Of 114 lesions, 33 were histologically malignant, and 81 were benign. UE was the most specific (95.1%) of the 3 modalities. The accuracy (81.7%) of UE was equal to mammography and was higher than those of US (82.5% and 71.9%, respectively). A combination of UE and US had the best sensitivity (90.9%) and accuracy (93.8%).

Conclusions

Ultrasound elastography is useful for breast lesion characterization and is an easier and cheaper method and more specific than mammography or US alone, but it is operator dependent. When combined with US, detection accuracy can be greatly improved and the combination potentially could reduce unnecessary biopsy.     

Real-time US elastography in the differentiation of suspicious microcalcifications on mammography

The purpose of this study was to retrospectively evaluate the use of US elastography in the differentiation of mammographically detected suspicious microcalcifications, using histology as the reference standard. Between May 2006 and April 2007, real-time US elasticity images were obtained in 77 patients (age range, 24–67 years; mean, 46 years) with 77 mammographically detected areas of microcalcifications (42 benign and 35 malignant lesions) prior to needle biopsy. Two experienced radiologists reviewed cine clips of elasticity and B-mode images and assigned an elasticity score of 1 to 3 in consensus, based on the degree of strain in the hypoechoic lesion without information of mammography and histology. For the elasticity score, the mean ± standard deviation was 1.5 ± 0.7 for benign and 2.7 ± 0.7 for malignant lesions (P < 0.001). When a cutoff point between elasticity scores of 1 and 2 was used, US elastography showed 97% (34/35) sensitivity, 62% (26/42) specificity, 68% (34/50) PPV, and 96% (26/27) NPV with an Az value of 0.852 (0.753–0.923, 95% confidence interval) in the differentiation of benign and malignant microcalcifications. Our results suggest that US elastography has the potential to differentiate benign and malignant lesions associated with microcalcifications detected at screening mammography.     

Role of sonographic elastography in the differential diagnosis of papillary lesions in breast

Purpose

The purpose of this study was to compare the diagnostic performance of elastography, conventional ultrasonography (US) and combined conventional US and elastography for differentiation of papillary breast lesions.

Materials and methods

A total of 95 papillary lesions (69 benign, 20 atypical and 6 malignant) in 87 patients were examined with conventional US and elastography. We evaluated conventional US images according to the Breast Imaging Reporting and Data System and internal composition (solid vs. cystic) and elastographic images according to elasticity scores. We compared diagnostic performances of elastography, conventional US and the combined method.

Results

Areas under the receiver-operating curve were 0.794 for elastography, 0.875 for conventional US and 0.787 for the combined method. When the elasticity score cutoff was between 2 and 3, the sensitivity, specificity, positive predictive value and negative predictive value were 100, 55.1, 13 and 100?%, respectively. The combined method showed similar sensitivity (100 vs. 100?%) to and higher specificity (57.3 vs. 5.6?%) than conventional US alone. No significant difference was found in the elasticity scores of cystic papillary lesions according to pathology.

Conclusion

Elastography improved the specificity of conventional US in differentiating between benign or atypical and malignant papillary breast lesions when it was combined with conventional US.     

Elastographie als Zusatzmodalität der Mammasonographie

In recent years the use of elastography in addition to sonography has become a routine clinical tool for the characterization of breast masses. Whereas free hand compression elastography results in qualitative imaging of tissue stiffness due to induced compression, shear wave elastography displays quantitative information of tissue displacement. Recent studies have investigated the use of elastography in addition to sonography and improvement of specificity in differentiating benign from malignant breast masses could be shown. Therefore, additional use of elastography could help to reduce the number of unnecessary biopsies in benign breast lesions especially in category IV lesions of the ultrasound breast imaging reporting data system (US-BI-RADS).     

Incremental value of real-time ultrasound elastography in differentiating breast masses

Aim of the work

To evaluate the value of real-time ultrasound elastography (RTE) in differentiating benign from malignant breast masses.

Materials and methods

This study included, whether palpable or non-palpable, 145 sonographically proven breast masses in 121 patients, imaged by conventional B-mode US, color-flow Doppler US and RTE with histopathological analysis considered as the golden standard reference.

Results

Lesions were differentiated into benign and malignant by conventional B-mode US (79; 45.5% and 66; 54.5%, respectively), RTE (80; 55.2% and 65; 44.8% respectively), and histopathology (82; 56.6% and 63; 43.4%, respectively). The mean difference in the mass size was significant between B-mode US and RTE in malignant masses (P = 0.002), while not significant among benign masses (P = 0.153). The B-mode US depicted sensitivity of 92.06%, specificity of 90.24%, PPV of 87.88%, NPV of 93.67% and accuracy of 91.03%, while the RTE showed sensitivity of 98.41%, specificity of 96.34%, PPV of 95.38%, NPV of 98.75% and accuracy of 97.24%.

Conclusion

Combined use of RTE can complement conventional B-mode US with improving its diagnostic performance in differentiating breast lesions with subsequent reduction in the rate of unnecessary biopsies in benign lesions.     

Qualitative pattern classification of shear wave elastography for breast masses: How it correlates to quantitative measurements

Objective

To determine the correlation of qualitative shear wave elastography (SWE) pattern classification to quantitative SWE measurements and whether it is representative of quantitative SWE values with similar performances.

Methods

From October 2012 to January 2013, 267 breast masses of 236 women (mean age: 45.12 ± 10.54 years, range: 21–88 years) who had undergone ultrasonography (US), SWE, and subsequent biopsy were included. US BI-RADS final assessment and qualitative and quantitative SWE measurements were recorded. Correlation between pattern classification and mean elasticity, maximum elasticity, elasticity ratio and standard deviation were evaluated. Diagnostic performances of grayscale US, SWE parameters, and US combined to SWE values were calculated and compared.

Results

Of the 267 breast masses, 208 (77.9%) were benign and 59 (22.1%) were malignant. Pattern classifications significantly correlated with all quantitative SWE measurements, showing highest correlation with maximum elasticity, r = 0.721 (P < 0.001). Sensitivity was significantly decreased in US combined to SWE measurements to grayscale US: 69.5–89.8% to 100.0%, while specificity was significantly improved: 62.5–81.7% to 13.9% (P < 0.001). Area under the ROC curve (A_z) did not show significant differences between grayscale US to US combined to SWE (P > 0.05).

Conclusion

Pattern classification shows high correlation to maximum stiffness and may be representative of quantitative SWE values. When combined to grayscale US, SWE improves specificity of US.     

Diagnostic performance of sonoelastographic Tsukuba score and strain ratio in evaluation of breast masses

The aim of this prospective study was to evaluate the diagnostic performance of the use of strain index ratio by sonoelastography to differentiate between benign and malignant breast lesions.