Ultrasound elastography as an adjuvant to conventional ultrasound in the preoperative assessment of axillary lymph nodes in suspected breast cancer: a pilot study

Associations of Real-Time Ultrasound and Strain and Shear Wave Elastography with Gastrointestinal Organs: A Systematic Review

Ultrasound elastography is gaining attention for its diagnostic potential across various medical fields, and its physical properties make it valuable in modern clinical medicine. However, its specific attributes, especially in the context of recent medical advancements, remain relatively unexplored. This study aimed to identify instrument-specific characteristics and applications of real-time ultrasound elastography, shear wave elastography, and strain elastography, particularly within gastroenterology. Following PRISMA guidelines, the study examined elastography articles on databases like PubMed, resulting in 78 included articles. Data on patient demographics, organ involvement, specificity, sensitivity, accuracy, positive predictive value, and negative predictive value were extracted. Statistical analysis involved SPSS version 21, with significance set at p < 0.05. The majority of patients were male (50.50%), with a mean age of 42.73 ± 4.41 years. Shear wave elastography was the most prevalent technique (48.7%), and liver investigations were predominant in gastroenterology (34.6%). Gastrointestinal applications showed higher sensitivity, positive predictive value, and negative predictive values (p < 0.05) but lower specificity (p < 0.05). Real-time ultrasound elastography exhibited increased specificity, accuracy, and predictive values (p < 0.05). Ultrasound elastography appears more accurate and effective in gastroenterological settings. Nonetheless, its performance depends on instrument-specific and operator-dependent factors. While promising, further studies are necessary to ascertain optimal utilization in both gastrointestinal and non-gastrointestinal conditions.

Stretchable ultrasonic arrays for the three-dimensional mapping of the modulus of deep tissue

Serial assessment of the biomechanical properties of tissues can be used to aid the early detection and management of pathophysiological conditions, to track the evolution of lesions and to evaluate the progress of rehabilitation. However, current methods are invasive, can be used only for short-term measurements, or have insufficient penetration depth or spatial resolution. Here we describe a stretchable ultrasonic array for performing serial non-invasive elastographic measurements of tissues up to 4 cm beneath the skin at a spatial resolution of 0.5 mm. The array conforms to human skin and acoustically couples with it, allowing for accurate elastographic imaging, which we validated via magnetic resonance elastography. We used the device to map three-dimensional distributions of the Young's modulus of tissues ex vivo, to detect microstructural damage in the muscles of volunteers before the onset of soreness and to monitor the dynamic recovery process of muscle injuries during physiotherapies. The technology may facilitate the diagnosis and treatment of diseases affecting tissue biomechanics.

Diagnostic Efficacy of Ultrasonography, Doppler Ultrasonography and Elastography in the Evaluation of Suspected Malignant Lymph Nodes

Aim

In this prospective study, the efficiency of imaging findings was investigated by comparing the histopathological results of lymph nodes with Doppler and ultrasound features and elasticity scores.

Material and method

A total of 100 cervical or axillary lymph nodes with a suspected malignancy or whose size did not decrease after treatment were examined. In addition to the demographic data of the patients, B-mode ultrasound, Doppler ultrasound, and elastography features of the lymph nodes were evaluated prospectively. The irregular shape, increased size, pronounced hypoechogenicity, presence of micro/macro calcification, short axis/long axis ratio >2, increased size of the short axis, increased cortex thickness, obliterated hilus or increased cortex thickness >3.5 mm were evaluated on ultrasound. Resistivity index, pulsatility index, acceleration rate and time were evaluated for intranodal arterial structures on color. Doppler ultrasound, strain ratio value and elasticity score were recorded on ultrasound elastography. After sonographic examination, patients underwent ultrasound-guided fine needle aspiration cytology or tru-cutting needle biopsy. Histopathological examination results of the patients were compared with the B-mode ultrasound, Doppler ultrasound, and ultrasound elastography.

Results

When the individual and combined effects of the ultrasound, Doppler ultrasound, and ultrasound elastography were evaluated, the combination of all three imaging methods was found to have the highest sensitivity and the highest overall accuracy (90.4% and 73.9%). As an individual method Doppler ultrasound had the highest specificity (77.8%). B-mode ultrasound was found to have the lowest accuracy (56.7%) both in individual and combined evaluations.

Conclusion

Addition of ultrasound elastography to the combination of B-mode and Doppler ultrasound findings increases diagnostic sensitivity and accuracy in the differentiation of benign and malignant lymph nodes.

Diagnostic Values of 8 Different Imaging Modalities for Preoperative Detection of Axillary Lymph Node Metastasis of Breast Cancer: A Bayesian Network Meta-analysis

OBJECTIVE

This study aimed to compare diagnostic performances of 8 different imaging modalities for preoperative detection of axillary lymph node (LN) metastasis in patients with breast cancer by performing a network meta-analysis (NMA) using direct comparison studies with 2 or more imaging techniques.

MATERIALS AND METHODS

PubMed, Cochrane, and Embase were searched for the studies evaluating the performances of 8 different imaging modalities for preoperative axillary LN staging in patients with breast cancer. The NMA was performed in patient-based analyses. The consistency was evaluated by examining the agreement between direct and indirect treatment effects, and publication bias was assessed by funnel plot asymmetry tests. The surface under the cumulative ranking curve (SUCRA) values were obtained to calculate the probability of each imaging modality being the most effective diagnostic method.

RESULTS

A total of 2197 patients from 22 direct comparison studies using 8 different imaging modalities for preoperative detection of axillary LN metastasis in patients with breast cancer were included. For preoperative detection of axillary LN metastasis of breast cancer, elastography showed the highest SUCRA values of sensitivity, specificity, positive predictive value, negative predictive value, accuracy, and diagnostic odds ratio. In addition, fluorine-18 fluorodeoxyglucose positron emission tomography (PET) or PET/computed tomography, fluorine-18 fluorodeoxyglucose PET/magnetic resonance, and contrast-enhanced computed tomography showed high SUCRA values.

CONCLUSION

Elastography showed the highest SUCRA values. Seven imaging modalities showed the complementary diagnostic roles for preoperative detection of axillary LN metastasis in patients with breast cancer, except mammography.

Application of multimodal ultrasonography for differentiating benign and malignant cervical lymphadenopathy

OBJECTIVES

The purpose of this study was to evaluate the diagnostic value of multimodal ultrasonography, including SWE and CEUS, for the differentiation of benign and malignant cervical lymphadenopathy.

METHODS

A total of 103 patients with 109 enlarged neck lymph nodes underwent SWE and CEUS. There were 25 hyperplastic lymph nodes, 66 metastatic lymph nodes, and 18 cases of lymphoma.

RESULTS

Using 31.6 kPa as the Emax cutoff, the sensitivity, specificity and accuracy of measurements on both benign and malignant cervical lymph nodes were 55.95%, 96%, and 65.2%, respectively. CEUS showed that lymph nodes with reactive hyperplasia mainly exhibited uniform perfusion via the lymphatic hilum (18/25; 72%; P < 0.01). The main manifestation of lymphoma was uniform perfusion through the lymphatic hila (10/18; 55.6%; P < 0.01). Metastatic lymph nodes mainly exhibited uneven perfusion (57/66; 86.4%; P < 0.01). The sensitivity, specificity, and accuracy of multimodal ultrasonography for the diagnosis of benign and malignant cervical lymphadenopathies were 90.5%, 72%, and 86.2%, respectively.

CONCLUSIONS

Our findings suggest that multimodal ultrasonography can detect the stiffness (elasticity), perfusion pattern, and characteristics of lymph nodes and is a valuable tool for differentiating between benign and malignant lymphadenopathies.

Specimen number based diagnostic yields of suspicious axillary lymph nodes in core biopsy in breast cancer: clinical implications from a prospective exploratory study

Background

Ultrasound (US)-guided core needle biopsy (CNB) is widely applied in the pathological diagnosis of suspicious axillary lymph nodes (ALNs) in breast cancer. However, the number of specimens removed during biopsy is currently based on the preference of the individual radiologist. This study aims to analyze the specimen number based diagnostic yields of US guided CNB of suspicious ALNs in breast cancer.

Methods

Core biopsy specimens of suspicious lymph nodes were prospectively obtained from breast cancer patients treated at our hospital between November, 2018, and July, 2019. Four specimens were obtained from each patient and labeled 1-4 in the order they were removed. Each specimen underwent pathological evaluation to determine whether metastasis had occurred. The diagnostic yields of the specimens were calculated and differences in diagnostic accuracy according to the number of specimens were evaluated by McNemar's test.

Results

A total of 167 patients were enrolled, and 139 (83.2%) cases were identified as metastasis by CNB. The diagnostic yields were: 74.2% (specimen 1), 87.8% (specimens 1-2), 91.2% (specimens 1-3), and 94.6% (specimens 1-4). The increases in diagnostic yield from specimen 1 to 1-2 and from specimens 1-2 to 1-4 were significant; however, no significant differences were detected between specimens 1-3 and the first two, or between specimens 1-4 and the first three in this sample size. The lower diagnostic abilities for the first two specimens were associated with shorter long- and short-axis lengths of lymph nodes on US.

Conclusions

Although the second specimen contributed significant diagnostic yield of suspicious axillary lymph nodes in core biopsy in breast cancer, a minimum number cannot be determined by this study. Additional specimens may improve diagnostic yield particularly in patients with small nodes.

Nomogram for Predicting Lymph Node Involvement in Triple-Negative Breast Cancer

Background

Lymph node metastasis of triple-negative breast cancer (TNBC) is essential in treatment strategy formulation. This study aimed to build a nomogram that predicts lymph node metastasis in patients with TNBC.

Materials and Methods

A total of 28,966 TNBC patients diagnosed from 2010 to 2017 in the Surveillance, Epidemiology and End Results (SEER) database were enrolled, and randomized 1:1 into the training and validation sets, respectively. Univariate and multivariate logistic regression analysis were applied to identify the predictive factors, which composed the nomogram. The receiver operating characteristic curves showed the efficacy of the nomogram.

Result

Multivariate logistic regression analyses revealed that age, race, tumor size, tumor primary site, and pathological grade were independent predictive factors of lymph node status. Integrating these independent predictive factors, a nomogram was successfully developed for predicting lymph node status, and further validated in the validation set. The areas under the receiver operating characteristic curves of the nomogram in the training and validation sets were 0.684 and 0.689 respectively, showing a satisfactory performance.

Conclusion

We constructed a nomogram to predict the lymph node status in TNBC patients. After further validation in additional large cohorts, the nomogram developed here would do better in predicting, providing more information for staging and treatment, and enabling tailored treatment in TNBC patients.

Diagnostic Performance of Quantitative and Qualitative Elastography for Axillary Lymph Node Metastasis in Breast Cancer: A Systematic Review and Meta-Analysis

Background: Studies have shown inconsistent results regarding the diagnostic performance of ultrasound elastography for axillary lymph node metastasis (ALNM) in breast cancer. This meta-analysis aimed to estimate the diagnostic performance of ultrasound elastography (divided into quantitative and qualitative elastography) for ALNM in patients with breast cancer. Methods: The PubMed and Embase databases were searched for eligible studies exploring the diagnostic performance of ultrasound elastography for ALNM in patients with breast cancer. The included studies were divided into quantitative and qualitative elastography groups to perform separate meta-analyses. The diagnostic performance was investigated with pooled sensitivity and specificity and diagnostic odds ratio (DOR) using a bivariate mixed-effects regression model. A summary receiver operating characteristic curve was constructed, and the area under the curve (AUC) was calculated. Results: Seven and 11 studies were included in the quantitative and qualitative elastography meta-analyses, respectively. The pooled sensitivity and specificity, DOR, and AUC with their corresponding 95% confidence intervals were 0.82 (0.75, 0.87), 0.88 (0.78, 0.93), 33 (13, 83), and 0.89 (0.86, 0.91), respectively, for quantitative elastography and 0.81 (0.69, 0.89), 0.92 (0.79, 0.97), 46 (12, 181), and 0.92 (0.89, 0.94), respectively, for qualitative elastography. No significant publication bias existed. Fagan plots demonstrated good clinical utility. However, substantial heterogeneity existed among studies. Study design, measurement, and reference standard served as potential sources of heterogeneity for quantitative studies, which were measurement and reference standard for qualitative studies. Conclusions: Both quantitative and qualitative elastography seem to be feasible, non-invasive diagnostic tools for ALNM in breast cancer. Nevertheless, the results must be interpreted carefully, paying attention to heterogeneity issues, especially for quantitative elastography studies.

A Brief Review on Breast Carcinoma and Deliberation on Current Non Invasive Imaging Techniques for Detection

BACKGROUND

Breast carcinoma is a life threatening disease that accounts for 25.1% of all carcinoma among women worldwide. Early detection of the disease enhances the chance for survival.

DISCUSSION

This paper presents comprehensive report on breast carcinoma disease and its modalities available for detection and diagnosis, as it delves into the screening and detection modalities with special focus placed on the non-invasive techniques and its recent advancement work done, as well as a proposal on a novel method for the application of early breast carcinoma detection.

CONCLUSION

This paper aims to serve as a foundation guidance for the reader to attain bird's eye understanding on breast carcinoma disease and its current non-invasive modalities.

Axillary Nodal Evaluation in Breast Cancer: State of the Art

Axillary lymph node (LN) metastasis is the most important predictor of overall recurrence and survival in patients with breast cancer, and accurate assessment of axillary LN involvement is an essential component in staging breast cancer. Axillary management in patients with breast cancer has become much less invasive and individualized with the introduction of sentinel LN biopsy (SLNB). Emerging evidence indicates that axillary LN dissection may be avoided in selected patients with node-positive as well as node-negative cancer. Thus, assessment of nodal disease burden to guide multidisciplinary treatment decision making is now considered to be a critical role of axillary imaging and can be achieved with axillary US, MRI, and US-guided biopsy. For the node-positive patients treated with neoadjuvant chemotherapy, restaging of the axilla with US and MRI and targeted axillary dissection in addition to SLNB is highly recommended to minimize the false-negative rate of SLNB. Efforts continue to develop prediction models that incorporate imaging features to predict nodal disease burden and to select proper candidates for SLNB. As methods of axillary nodal evaluation evolve, breast radiologists and surgeons must work closely to maximize the potential role of imaging and to provide the most optimized treatment for patients.

Diagnostic value of ultrasound elastography for differentiation of benign and malignant axillary lymph nodes: a meta-analysis

AIM

To investigate the diagnostic value of ultrasound elastography (UE) for benign and malignant axillary lymph nodes.

MATERIALS AND METHODS

A literature search was conducted from PubMed, Cochrane EMBASE, and Medline. Fourteen studies including 1,186 patients with 1,411 lymph nodes were enrolled. Overall, diagnostic descriptive statistics included pooled sensitivity, specificity, and area under the receiver operating characteristic curve (AUC) with corresponding 95% confidence intervals (95% CIs) were generated by random effect model. Subgroup analyses were performed in (real-time elastography [RTE] versus shear wave elastography [SWE]) and (conventional ultrasound versus combination of traditional ultrasound and elastography). Meta-regression was used to explore potential sources of heterogeneity.

RESULTS

The overall pooled sensitivity, specificity, and AUC of UE was 0.79 (95% CI: 0.71-0.86), 0.90 (95% CI: 0.83-0.95), and 0.91 (95% CI: 0.88-0.93), respectively. In the subgroup analysis of the two UE techniques, the pooled sensitivity, specificity, and AUC of SWE was higher than that of RTE (sensitivity: 0.82>0.77; specificity: 0.91>0.89; AUC: 0.94>0.89). The pooled diagnostic value of ultrasound combined with UE were significantly improving compared with traditional ultrasound (sensitivity: 0.87>0.82, specificity: 0.83>0.78, and AUC: 0.91>0.87). No independent heterogeneous factor was found in meta-regression.

CONCLUSION

The results indicate that UE was an effective technique for identifying malignant axillary lymph nodes due to its high diagnostic efficiency, which can provide useful information for surgical procedure selection.

Role of gamma probe-assisted intraoperative sentinel lymph node evaluation in predicting axillary breast cancer metastasis after neoadjuvant chemotherapy

OBJECTIVE

Intraoperative sentinel lymph node biopsy is a universally accepted technique to identify patients who are candidates for axillary lymph node dissection during breast cancer surgery. However, there is controversy over its use in patients who underwent preoperative neoadjuvant chemotherapy. This study aimed to examine the diagnostic value of gamma probe-assisted intraoperative sentinel lymph node examination with frozen section in breast cancer patients who had undergone preoperative neoadjuvant chemotherapy.

METHODS

This retrospective study included 94 tumors diagnosed with stage IIA, IIB or IIIA invasive breast cancer with locoregional lymph node metastasis who underwent surgical treatment after neoadjuvant chemotherapy. Intraoperatively, axillary sentinel lymph node sampling was done using radioactive colloid and gamma probe and materials were examined with frozen section method. Patients with positive sentinel nodes underwent axillary resection. Histopathological examination of all surgical samples was done postoperatively.

RESULTS

In 87 of 94 tumors (92.6%), a sentinel lymph node could be identified using the method. The sensitivity, specificity and accuracy of the method for predicting axillary macro metastasis were 85.7, 86.5 and 86.2%, respectively, with 5.7% false negative rate.

CONCLUSIONS

Sentinel lymph node identification using preoperative scintigraphy and intraoperative use of gamma probe seems to be a feasible and efficient method in terms of differentiating patients that require axillary lymph node dissection during breast cancer surgery, even when they have received neoadjuvant chemotherapy. Further large prospective studies allowing subgroup analyses are warranted.

Role of sonoelastography in assessment of axillary lymph nodes in breast cancer: a systematic review and meta-analysis

AIM

To evaluate the effectiveness of shear-wave elastography (SWE) and strain elastography (SE) for axillary lymph nodes (ALNs).

MATERIALS AND METHODS

PubMed, Embase, and Cochrane Library databases were searched until September 2018. Weighted mean difference was calculated for continuous variables. The accuracy of sonoelastography was assessed by calculating pooled sensitivity, specificity, area under the curve (AUC), positive likelihood ratio (PLR), negative likelihood ratio (NLR), and diagnostic odds ratio (DOR). All data were analysed using Stata 12.0.

RESULTS

Ten studies with 1,038 ALNs were included in the meta-analysis. Five studies evaluated the use of SE, and the other five evaluated the SWE. The SWE stiffness values of malignant ALNs were significantly higher than those of benign nodes. Both SE and SWE have relatively high specificity and sensitivity. The max stiffness in SWE showed the highest specificity (0.94; 95% confidence interval [CI], 0.81-0.98), PLR (12.1; 95% CI, 4-36.5), NLR (0.29; 95% CI, 0.12-0.69), AUC (0.94; 95% CI, 0.91-0.96), and DOR (42; 95% CI, 12-154); in contrast, the mean stiffness showed the highest sensitivity (0.80; 95% CI, 0.61-0.91).

CONCLUSION

Sonoelastography demonstrated high sensitivity and specificity for differentiating between malignant and benign ALNs. The max and mean stiffness on SWE appeared to exhibit the highest accuracy. Thus, SWE is an effective accompaniment to sentinel node biopsy, and is appropriate for preoperative assessment of ALNs in the post-Z0011 era.

Usefulness of real-time elastography for diagnosing lymph node metastasis of skin cancer: does elastography potentially eliminate the need for sentinel lymph node biopsy in squamous cell carcinoma?

BACKGROUND

The metastatic involvement of regional lymph nodes is the most important prognostic factor for overall survival of skin cancer patients. The sonographic technique of freehand real-time tissue elastography (RTE), which displays tissue rigidity as a colour overlay of the tissue image, was developed.

OBJECTIVE

Our purpose was to evaluate the benefit of RTE for detecting lymph node metastases of skin cancer non-invasively before operation.

METHODS

We first selected lymph nodes of skin cancer patients which had already been diagnosed by biopsy as being reactive or metastatic, and then retrospectively collected images of RTE and B-mode and colour Doppler ultrasound on those lymph nodes performed preoperatively. Twenty-one lymph nodes from 12 patients with squamous cell carcinoma (SCC), 23 lymph nodes from 14 patients with malignant melanoma (MM) and 14 lymph nodes from six patients with extramammary Paget disease (Paget) were investigated. Elastographic images were assessed on a scale of one to four according to the percentage of high elasticity (hard) area (HEA) in the lymph node.

RESULTS

In all three skin cancers, lymph nodes evaluated as grade 3 or 4 by RTE were metastatic. All lymph nodes evaluated as grade 1 or 2 by RTE were reactive in SCC, whereas some lymph nodes evaluated as grade 1 or 2 were metastatic in MM and Paget.

CONCLUSION

Real-time tissue elastography may aid in distinguishing reactive lymph nodes from metastatic ones especially in SCC.

Sonography and sonoelastography in the detection of malignancy in superficial lymph nodes of dogs

BACKGROUND

The clinical applicability of sonography and sonoelastography (SOE) in the detection of lymph node malignancy in dogs has not been established.

OBJECTIVES

To compare sonographic and sonoelastographic findings between malignant and benign superficial lymph nodes and to evaluate the diagnostic performance of those methods.

ANIMALS

One-hundred sixteen lymph nodes of 54 dogs.

METHODS

A prospective observational study was used to investigate sonographic features and elasticity scores of malignant and benign superficial lymph nodes. Lymph nodes were categorized as malignant or benign according to cytology or histopathology. Quantitative variables were compared using Student's unpaired t test. Prevalence of categorical variables was compared using nonparametric Mann-Whitney U test. Diagnostic performance was calculated by receiver-operating characteristic analysis.

RESULTS

Forty-nine malignant and 67 benign lymph nodes were included. Malignant nodes had larger long axis (LA; P = .0002), short axis (SA; P < .0001) and short-to-long axis ratio (P < .0001) in comparison with benign nodes. Malignant nodes had a higher prevalence of mixed vascular distribution on Doppler color flow mapping (P < .005) and on power Doppler (P < .0001) and higher resistivity index (RI; P < .0001), pulsatility index (P < .0001), and elasticity score (P < .0001) in comparison with benign nodes. Short axis, elasticity score, and RI offered the best accuracies, 80.2%, 78.1%, and 77.7% (P < .05), respectively, for malignancy detection.

CONCLUSIONS AND CLINICAL IMPORTANCE

Results support the use of Doppler sonography and SOE as auxiliary methods to brightness mode sonography to detect nodal malignancy.

Diagnostic value of magnetic resonance imaging using superparamagnetic iron oxide for axillary node metastasis in patients with breast cancer: a meta-analysis

Objectives Identification of axillary metastases in breast cancer is important for staging disease and planning treatment, but current techniques are associated with a number of adverse events. This report evaluates the diagnostic accuracy of superparamagnetic iron oxide (SPIO)-enhanced magnetic resonance imaging (MRI) techniques for identification of axillary metastases in breast cancer patients. Methods We performed a meta-analysis of previous studies that compared SPIO enhanced MRI with histological diagnosis after surgery or biopsy. We searched PubMed, Ovid, Springer Link, and Cochrane library to identify studies reporting data for SPIO enhanced MRI for detection of axillary lymph node metastases in breast cancer until December 2013. The following keywords were used: “magnetic resonance imaging AND axilla” and “superparamagnetic iron oxide AND axilla”. Eligible studies were those that compared SPIO enhanced MRI with histological diagnosis. Sensitivity and specificity were calculated for every study; summary receiver operating characteristic and subgroup analyses were done. Study quality and heterogeneity were also assessed. Results There were 7 publications that met the criteria for inclusion in our meta-analysis. SROC curve analysis for per patient data showed an overall sensitivity of 0.83 (95% Confidence interval (CI): 0.75–0.89) and overall specificity of 0.97 (95% CI: 0.94–0.98). Overall weighted area under the curve was 0.9563. Conclusions SPIO enhanced MRI showed a trend toward high diagnostic accuracy in detection of lymph node metastases for breast cancer. So, when the breast cancer patients has axillary metastases histologically, SPIO enhanced MRI may be effective diagnostic imaging modality for axillary metastases.

Application of Real-time Elastography Ultrasound in the Diagnosis of Axillary Lymph Node Metastasis in Breast Cancer Patients

The pathological status of axillary lymph nodes (ALN) plays a critical role in the staging and treatment of patients with breast cancer. Therefore, differential diagnosis of metastatic ALN is highly desirable in the clinic. We used real-time elastography (RTE) and gray-scale ultrasound to generate a new scoring system for determining ALN status and estimate their performance of this system. Ninety-seven ALNs were examined by both gray-scale ultrasound and RTE. The performance of gray-scale ultrasound was evaluated by the sum of scores according to its features. RTE images were determined by a modulated scoring system based on the percentage and distribution of hypoechoic cortex regions in the ALNs. Strain ratio was also calculated. Diagnostic performance was obtained by receiver operating characteristic curve analysis with pathologic findings used as the reference standard. The sensitivity, specificity and accuracy were 92%, 73% and 83%, respectively, for gray-scale ultrasound; 78%, 93%, 86%, respectively, for RTE; 88%, 96% and 92%, respectively, for the combined evaluation (AUC = 0.963), and 87%, 76% and 81%, respectively, for strain ratio. Gray-scale ultrasonography had a better sensitivity than RTE (92% vs 78%, P = 0.039), while the specificity for RTE was superior to that of gray-scale ultrasonography (93% vs 73%, P = 0.012). In conclusion, RTE showed a high specificity for evaluating the ALN status and may improve the diagnostic accuracy when combined with gray-scale ultrasound.

Ex Vivo Shear-Wave Elastography of Axillary Lymph Nodes to Predict Nodal Metastasis in Patients with Primary Breast Cancer

Purpose

There is still a clinical need to easily evaluate the metastatic status of lymph nodes during breast cancer surgery. We hypothesized that ex vivo shear-wave elastography (SWE) would predict precisely the presence of metastasis in the excised lymph nodes.

Methods

A total of 63 patients who underwent breast cancer surgery were prospectively enrolled in this study from May 2014 to April 2015. The excised axillary lymph nodes were examined using ex vivo SWE. Metastatic status was confirmed based on the final histopathological diagnosis of the permanent section. Lymph node characteristics and elasticity values measured by ex vivo SWE were assessed for possible association with nodal metastasis.

Results

A total of 274 lymph nodes, harvested from 63 patients, were examined using ex vivo SWE. The data obtained from 228 of these nodes from 55 patients were included in the analysis. Results showed that 187 lymph nodes (82.0%) were nonmetastatic and 41 lymph nodes (18.0%) were metastatic. There was significant difference between metastatic and nonmetastatic nodes with respect to the mean (45.4 kPa and 17.7 kPa, p<0.001) and maximum (55.3 kPa and 23.2 kPa, p<0.001) stiffness. The elasticity ratio was higher in the metastatic nodes (4.36 and 1.57, p<0.001). Metastatic nodes were significantly larger than nonmetastatic nodes (mean size, 10.5 mm and 7.5 mm, p<0.001). The size of metastatic nodes and nodal stiffness were correlated (correlation coefficient of mean stiffness, r=0.553). The area under curve of mean stiffness, maximum stiffness, and elasticity ratio were 0.794, 0.802, and 0.831, respectively.

Conclusion

Ex vivo SWE may be a feasible method to predict axillary lymph node metastasis intraoperatively in patients undergoing breast cancer surgery.

Role of Elastography in Axillary Examination of Patients With Breast Cancer

OBJECTIVES

This study aimed at exploring the role of ultrasound (US) elastography in the diagnosis of the axillary lymph node status in patients with breast cancer.

METHODS

We analyzed 140 visible axillary lymph nodes on conventional US imaging. All of them underwent elastography. Five conventional US features were adopted to assess axillary lymph nodes: longitudinal diameter, longitudinal-to-transverse diameter ratio, cortical thickness, status of the hilum, and vascular pattern. As for elastography, the proportion of the hard area within each lymph node was estimated visually. The lymph node was defined as positive on elastography when the proportion was 50% or greater. Meanwhile, disjunctive and conjunctive combinations of US and elastography were adopted to evaluate the lymph nodes. The histopathologic diagnosis was regarded as the reference standard.

RESULTS

The sensitivity, specificity, and accuracy were 76.92%, 87.10%, and 81.43%, respectively, for conventional US and 84.62%, 83.87%, and 84.29% for the disjunctive combination. The conjunctive combination had specificity of 100% and a positive predictive value of 100%, whereas the sensitivity was low.

CONCLUSIONS

Elastography can improve the sensitivity when disjunctively combined with conventional US for diagnosis of the axillary lymph node status. Despite the low sensitivity, the conjunctive combination of US and elastography can improve the positive predictive value on a large scale. Elastography is a useful adjuvant tool in addition to conventional US for the preoperative assessment of axillary lymph nodes in patients with breast cancer.

EUS elastography: How to do it?

Strain elastography as used in EUS (EUS-real-time tissue elastography [RTE]) is a qualitative technique and provides information on the relative stiffness between one tissue and another. This article reviews the principles, technique, and interpretation of EUS-RTE in various organs. It includes information on how to optimize the technique as well as a discussion on pitfalls and artifacts. We also refer to the article describing RTE using conventional ultrasound transducers.

Specific Ultrasound Data Acquisition for Tissue Motion and Strain Estimation: Initial Results

Ultrasound applications such as elastography can benefit from 3-D data acquisition and processing. In this article, we describe a specific ultrasound probe, designed to acquire series of three adjacent imaging planes over time. This data acquisition makes it possible to consider the out-of-plane motion that can occur at the central plane during medium scanning, and is proposed with the aim of improving the results of strain imaging. In this first study, experiments were conducted on phantoms, and controlled axial and elevational displacements were applied to the probe using a motorized system. Radiofrequency ultrasound data were acquired at a 40-MHz sampling frequency with an Ultrasonix ultrasound scanner, and processed using a 3-D motion estimation method. For each of the 2-D regions of interest of the central plane in pre-compression data, a 3-D search was run to determine its corresponding version in post-compression data, with this search taking into account the region-of-interest deformation model chosen. The results obtained with the proposed ultrasound data acquisition and strain estimation were compared with results from a classic approach and illustrate the improvement produced by considering the medium's local displacements in elevation, with notably an increase in the mean correlation coefficients achieved.

Elastosonography and two-dimensional ultrasonography in diagnosis of axillary lymph node metastasis in breast cancer

AIM

To compare diagnostic value of two-dimensional (2D) ultrasonography and elastosonography for suspected axillary lymph node metastasis of breast cancer.

MATERIALS AND METHODS

Elastosonography and 2D ultrasonography were performed on 78 axillary lymph nodes of 78 patients with suspected breast cancer. Scores of shape, long- to short-axis ratio, cortical thickness, and lymph node hilum were summed as the score of each lymph node at 2D ultrasonography, while a four-point scale was adopted for elasticity scoring. The combined score of each lymph node was obtained by summing the score at 2D ultrasonography and that at elasticity scoring. The strain ratio was calculated by comparison of the average strain of the lymph node with that of the subcutaneous tissue. Diagnostic efficacies of 2D ultrasonography, elasticity scoring, and the combined method were compared.

RESULTS

There were 78 axillary lymph nodes, including 34 non-metastatic and 44 metastatic nodes. The elasticity scores of non-metastatic and metastatic axillary lymph nodes were 1.44±0.82 and 3.11±0.75, respectively (p<0.05). The difference in area under the operating characteristic curve (AUC) was statistically significant between 2D ultrasonography and the combined method (p<0.05). The sensitivity, specificity, and accuracy of 2D ultrasonography and elasticity scoring were 77.3% versus 86.4%, 76.5% versus 85.3%, and 76.9% versus 85.9%, respectively (all p>0.05), and those of the combined method were 93.2%, 73.5%, and 84.6%, respectively. There was a significant difference in sensitivity between 2D ultrasonography and the combined method (p<0.05).

CONCLUSIONS

Combined application of 2D ultrasonography with elastosonography can improve the diagnostic capability for metastatic axillary lymph node characterisation in breast cancer.

Dual-modal computer-assisted evaluation of axillary lymph node metastasis in breast cancer patients on both real-time elastography and B-mode ultrasound

PURPOSE

To propose a computer-assisted method for quantifying the hardness of an axillary lymph node on real-time elastography (RTE) and its morphology on B-mode ultrasound; and to combine the dual-modal features for differentiation of metastatic and benign axillary lymph nodes in breast cancer patients.

MATERIALS AND METHODS

A total of 161 axillary lymph nodes (benign, n=69; metastatic, n=92) from 158 patients with breast cancer were examined with both B-mode ultrasound and RTE. With computer assistance, five morphological features describing the hilum, size, shape, and echogenic uniformity of a lymph node were extracted from B-mode, and three hardness features were extracted from RTE. Single-modal and dual-modal features were used to classify benign and metastatic nodes with two computerized classification approaches, i.e., a scoring approach and a support vector machine (SVM) approach. The computerized approaches were also compared with a visual evaluation approach.

RESULTS

All features exhibited significant differences between benign and metastatic nodes (p<0.001), with the highest area under the receiver operating characteristic curve (AUC) of 0.803 and the highest accuracy (ACC) of 75.2% for a single feature. The SVM on dual-modal features achieved the largest AUC (0.895) and ACC (85.7%) among all methods, exceeding the scoring (AUC=0.881; ACC=83.6%) and the visual evaluation methods (AUC=0.830; ACC=84.5%). With the leave-one-out cross validation, the SVM on dual-modal features still obtained an ACC as high as 84.5%.

CONCLUSION

Dual-modal features can be extracted from RTE and B-mode ultrasound with computer assistance, which are valuable for discrimination between benign and metastatic lymph nodes. The SVM on dual-modal features outperforms the scoring and visual evaluation methods, as well as all methods using single-modal features. The computer-assisted dual-modal evaluation of lymph nodes could be potentially used in daily clinical practice for assessing axillary metastasis in breast cancer patients.

Pre-Operative Evaluation of Axillary Lymph Node Status in Patients with Suspected Breast Cancer Using Shear Wave Elastography

The aim of this study was to evaluate shear wave elastography (SWE) for pre-operative evaluation of axillary lymph node (LN) status in patients with suspected breast cancer. A total of 130 axillary LNs in 130 patients who underwent SWE before fine-needle aspiration, core biopsy or surgery were analyzed. On gray-scale images, long and short axes, shape (elliptical or round), border (sharp or unsharp) and cortical thickening (concentric, eccentric or no fatty hilum) of LNs were assessed. On SWE, mean, maximum, minimum, standard deviation and the lesion-to-fat ratio (E_ratio) values of elasticity were collected. Gray-scale and SWE features were compared statistically between metastatic and benign LNs using the χ²-test and independent t-test. Diagnostic performance of each feature was evaluated using the area under the receiver operating characteristic curve (AUC). Logistic regression analysis was used to determine gray-scale or SWE features independently associated with metastatic LNs. Of the 130 LNs, 65 (50%) were metastatic and 65 (50%) were benign after surgery. Metastatic LNs were significantly larger (p = 0.018); had higher elasticity indexes at SWE (p < 0.0001); and had higher proportions of round shape (p = 0.033), unsharp border (p = 0.048) and eccentric cortical thickening or no fatty hilum (p = 0.005) compared with benign LNs. On multivariate analysis, E_ratio was independently associated with metastatic LNs (odds ratio = 3.312, p = 0.008). E_ratio had the highest AUC among gray-scale (0.582-0.719) and SWE (0.900-0.950) variables. SWE had good diagnostic performance in metastatic axillary LNs, and E_ratio was independently associated with metastatic LNs.

Value of Shear Wave Elastography Versus Contrast-Enhanced Sonography for Differentiating Benign and Malignant Superficial Lymphadenopathy Unexplained by Conventional Sonography

OBJECTIVES

This study aimed to compare the efficacy of shear wave elastography (SWE) and contrast-enhanced sonography in the differential diagnosis of superficial lymphadenopathy with abnormal imaging findings, which could not be otherwise confirmed by conventional sonography.

METHODS

Forty-two enlarged superficial lymph nodes in 42 patients who met the screening criteria for this study were evaluated by both contrast-enhanced sonography and SWE. All lymph nodes underwent both methods using biopsy pathologic findings as a reference standard.

RESULTS

The maximum elastic modulus, mean elastic modulus, and standard deviation of the elastic modulus were the main distinguishing features on SWE; they were significantly higher in malignant lesions than benign ones. The threshold value for the maximum elastic modulus was set at 37.9 kPa, and the sensitivity, specificity, and accuracy of differential diagnosis of superficial lymph nodes were 81.8%, 80.0%, and 81.0%, respectively. The diagnosis of benignity and malignancy by this index was statistically significant (P < .001). The lymph nodes were divided into benign and malignant groups according to different types based on the degree and range of intensity on contrast-enhanced sonography: intense or moderate homogeneous enhancement (n = 26) and heterogeneous, low homogeneous, or absent enhancement (n = 16). The sensitivity, specificity, and accuracy of contrast-enhanced sonography were 27.3%, 50.0%, and 38.1%. There was no statistically significant difference in the values between the benign and malignant groups (χ²  = 2.295; P = .130).

CONCLUSIONS

Compared with contrast-enhanced sonography, SWE has better diagnostic value and efficiency in differentiation of superficial lymph nodes unexplained by conventional sonography. When conventional sonography cannot differentiate malignant superficial lymph nodes from benign ones, SWE is a useful adjunctive tool for assessment of lymph nodes.

Quantitative evaluation of peripheral tissue elasticity for ultrasound-detected breast lesions

AIM

To evaluate the diagnostic performance of the quantitative measurement of peripheral tissue elasticity using shear-wave elastography (SWE) in differentiating between benign and malignant breast lesions detected by ultrasonography (US).

MATERIALS AND METHODS

This study was approved by institutional review board; informed consent was signed from all patients. From June 2012 to April 2014, conventional B-mode US and SWE were performed in 205 breast lesions (78 malignant, 127 benign) of 205 consecutive women (mean age, 41.9±12.3 years; age range, 18-76 years). For each lesion, a rim around its contour was constructed by using a computer-aided tool, including adequate adjacent peripheral tissue. Quantitative elastographic features of the rim (elasticity mean, maximum, standard deviation, and elasticity ratio) as well as Breast Imaging Reporting and Data System (BI-RADS) categories were assessed according to the final histopathological results. Sensitivity, specificity, positive and negative predictive values, and receiver operating characteristic (ROC) curve analysis were performed to evaluate the diagnostic performances for the three data sets (conventional B-mode US alone, SWE features alone, and combined B-mode US and SWE features).

RESULTS

SWE features of the peripheral tissue differed significantly between benign and malignant breast lesions (mean±standard deviation [SD]: elasticity mean, 16.1±6.6 versus 43.6±17.8; maximum, 55.4±31.4 versus 150.3±44.6; SD, 8.1±4.1 versus 30±13.8 and elasticity ratio, 1.1±0.2 versus 2±0.7, respectively, all p<0.001), and enabled significantly higher specificities compared with conventional B-mode US alone (92.9%, 84.3%, 94.5%, and 93.7% versus 44.1%, respectively, all p<0.001). The combinations of SWE assessment (including individual features and the logistic regression model of all four features) and conventional B-mode US for BI-RADS 3 and 4a lesions significantly improved the diagnostic performance compared with B-mode US alone, with significantly increased specificity (85%, 82.7%, 81.9%, 86.6%, and 85% versus 44.1%; all p<0.001) and AUC (0.942, 0.940, 0.940, 0.935, and 0.953 versus 0.916, all p<0.05).

CONCLUSION

Quantitative evaluation of the elastic properties of the peripheral tissue exhibited good discriminatory ability in differentiating US-detected breast lesions and could be used to further stratify low-suspicion lesions within BI-RADS category 3 and 4a to avoid unnecessary biopsy.

Ex Vivo Assessment of Sentinel Lymph Nodes in Breast Cancer Using Shear Wave Elastography

OBJECTIVES

Axillary lymph node status is one of the important prognostic factors in early-stage breast cancer. Despite the combined use of sonography, fine-needle aspiration, and sentinel lymph node (SLN) dissection, there is a gap between the potential effectiveness of those techniques and current success to determine the axillary lymph node status. The main aim of this study was to evaluate the baseline accuracy of shear wave elastography for differentiation of benign versus malignant SLNs in an ex vivo artifact-free environment.

METHODS

Thirty patients with breast cancer scheduled for SLN dissection were enrolled prospectively after informed consent and Institutional Review Board approval were obtained. After dissection, lymph nodes were embedded in ultrasound gel and examined with grayscale sonography and shear wave elastography. Findings were compared to histopathologic results.

RESULTS

A total of 64 SLNs obtained from the 30 patients were evaluated. Twelve of them (18.8%) were metastatic, and 52 (81.2%) were benign. The mean cortical thickness (benign versus metastatic, 1.6 versus 4.4 mm), short-axis length (4.63 versus 7.50 mm), cortical stiffness (10.7 versus 25.5 kPa), and hilar stiffness (7.5 versus 11.3 kPa) were statistically higher in metastatic lymph nodes (P ≤ .02). Area under the receiver operator characteristic curve values for these variables were 0.814, 0.768, 0.786, and 0.759, respectively. Cortical thickness was found to have the highest diagnostic performance, followed by cortical stiffness.

CONCLUSIONS

Shear wave elastography can be used with grayscale sonography for evaluation of cases to decide on needle biopsy sampling. However, it cannot be used as a replacement for fine-needle aspiration or SLN dissection.

Diagnostic accuracy of shear wave elastography for prediction of breast malignancy in patients with pathological nipple discharge

OBJECTIVES

Pathological nipple discharge (PND) may indicate malignant breast lesions. As the role of shear wave elastography (SWE) in predicting these malignant lesions has not yet been evaluated, we aim to evaluate the diagnostic value of SWE for this condition.

DESIGN

Prospective diagnostic accuracy study comparing a combination of qualitative and quantitative measurements of SWE (index test) to a ductoscopy and microdochectomy for histological diagnosis (reference test).

SETTING

Fuzhou General Hospital of Nanjing military command.

PARTICIPANTS

A total of 379 patients with PND were finally included from January, 2011 to March 2014, after we screened 1084 possible candidates. All participants were evaluated through SWE, with qualitative parameters generated by Virtual Touch tissue imaging (VTI) and quantitative parameters generated by Virtual Touch tissue quantification (VTQ). All the patients were consented to receive a ductoscopy and microdochectomy for histological diagnosis, and the results were set as a reference test.

OUTCOME MEASURES

Sensitivity and specificity of the combined VTI and VTQ of the SWE for detection of malignancy in patients with PND.

RESULTS

The 379 participants presented with 404 lesions. The results of pathological examination showed that 326 (80.7%) of the 404 lesions were benign and the other 78 (19.3%) were malignant. An area under the curve of elasticity score, VTQm and VTQc, were 0.872, 0.825 and 0.857, respectively, with the corresponding cut-off point as 2.50, 2.860 m/s and 3.015 m/s, respectively. After a combination of these measurements, the sensitivity, specificity, and positive and negative predictive value (PPV and NPV), were 89.7%, 72.1%, 43.5% and 96.7%, respectively. The sensitivity analysis showed 82% of the sensitivity and 96.8% of the specificity, in which patients with no pathological findings in ductoscopy were excluded.

CONCLUSIONS

Ultrasonographic elastography is sensitive for patients with PND and could be used as a triage test before ductoscopy examination. Studies for further improvement of diagnostic sensitivity are warranted.

Transcutaneous Ultrasound: Elastographic Lymph Node Evaluation. Current Clinical Applications and Literature Review

Distinguishing malignant versus benign lymphadenopathies is a major diagnostic dilemma in clinical medicine. Metastatic deposits in normal-sized lymph nodes (LNs) can be smaller than a millimeter, thus presenting a diagnostic challenge. In most clinical settings, however, enlarged LNs detected on imaging need to be classified as malignant or benign. Ultrasound seems to be a very reliable method for LN characterization because of the high resolution, especially in the subcutaneous areas. However, B-mode and Doppler-ultrasound criteria for characterization of a lymphadenopathy as benign or malignant are lacking specificity. Newer methods such as elastography seem to be valuable for identifying metastatic deposits within LNs and may help discriminate malignant and benign LNs. This review summarizes the different elastographic methods available and provides an overview of the relevant publications. According to the literature, elastography can be used for identifying metastatic deposits, to guide fine needle aspiration and to non-invasively choose the most suspicious LN of a group of enlarged LNs for targeted biopsy.

Positive impact of elastography in breast cancer diagnosis: an institutional experience

Elastography (ES) is a technique that, when associated with traditional B mode ultrasound (US), allows the degree of elasticity of tissue to be evaluated according to a color scale system. The aims of the study were to compare the diagnostic characteristics of two widely used techniques adopted in breast cancer screening; US and color Doppler (CD), with those of the same two techniques plus ES, and assessment of the same diagnostic characteristics when the three methods were applied to lesions < or >1 cm. Methods used included subjecting 212 women to investigations aimed at the early diagnosis of breast cancer outside the screening model, whereby 395 lesions were detected by US, ES, and CD, with a definitive diagnosis proved by histological exam. The diagnostic performance of US, ES, CD, and their combinations was calculated. The results showed that comparing the diagnostic characteristics of the three methods with reference to the definitive histological results for malignant breast lesions, the best diagnostic accuracy was obtained when US, ES, and CD were combined (0.837). For lesions <1 cm, diagnostic accuracy was 0.782, and for those >1 cm, it was 0.886. In the lesions <1 cm, which were more difficult to study, a positive ES score (>4) appeared to be sufficient to deepen the diagnosis, even though 35 % of the ES or US positive lesions were not malignant. By contrast, in lesions >1 cm, the probability of having a malignant lesion when all three tests were positive was very high (97 %). It was concluded that early diagnosis is a key factor in breast cancer, so an economically sustainable, non-invasive pathway is the target of diagnostic breast imaging.

Strain elastography of abnormal axillary nodes in breast cancer patients does not improve diagnostic accuracy compared with conventional ultrasound alone

OBJECTIVE

The purpose of this study was to determine the diagnostic value of strain elastography (SE) alone and in combination with gray-scale ultrasound in the diagnosis of benign versus metastatic disease for abnormal axillary lymph nodes in breast cancer patients.

SUBJECTS AND METHODS

Patients with breast cancer and axillary lymph nodes suspicious for metastatic disease on conventional ultrasound who underwent SE of the suspicious node before ultrasound-guided fine-needle aspiration biopsy (FNAB) were included in this study. On conventional ultrasound, the long- and short-axis diameters, long-axis-to-short-axis ratio, cortical echogenicity, thickness, and evenness were documented. The nodal vascularity was assessed on power Doppler imaging. Elastograms were evaluated for the percentage of black (hard) areas in the lymph node, and the SE-ultrasound size ratio was calculated. Two readers assessed the images independently and then in consensus in cases of disagreement. ROC AUCs were calculated for conventional ultrasound, SE, and both methods combined. Interreader reliability was assessed using kappa statistics.

RESULTS

A total of 101 patients with 104 nodes were examined; 35 nodes were benign, and 69 had metastases. SE alone showed a significantly lower AUC (62%) than did conventional ultrasound (92%) (p<0.001). There was no difference between the AUC of conventional ultrasound and the AUC of the combination of conventional ultrasound and SE (93%) (p=0.16). Interreader reliability was moderate for all variables (κ≥0.60) except the SE-ultrasound size ratio (κ=0.35).

CONCLUSION

Added SE does not improve the diagnostic ability of conventional ultrasound when evaluating abnormal axillary lymph nodes.

Real-time elastography of cervical lymph nodes in Kikuchi disease

We report, to our knowledge, the first cases of sonographic and real-time elastographic findings of cervical lymph nodes in patients with Kikuchi disease. Cervical lymph nodes had probably benign findings on grayscale sonography and real-time elastography.

Accuracy of real-time ultrasound elastography in the differential diagnosis of lymph nodes in cutaneous malignant melanoma (CMM): a pilot study

BACKGROUND

We investigated the diagnostic ability of real-time elastography to differentiate between reactive and metastatic lymph nodes in cutaneous malignant melanoma (CMM) patients and to determine the optimum cutoff value for elastography scores for diagnosis CMM.

METHODS

Twenty lymph nodes (metastatic, n = 13; reactive, n = 7) from 12 patients with CMM were examined by both elastography and B-mode ultrasound in this prospective study. Elastographic patterns were given scores of 1-5 according to the percentage of high elasticity (hard) areas in the lymph node. Elastographic patterns 1, 2, 3, 4, and 5 were assigned elastography scores (ES) of 1, 2, 3, 4, and 5, respectively. B-mode ultrasound diagnosis was performed on the basis of the morphological patterns (balloon-shaped lymph node and loss of central echoes). The sensitivity, specificity, and accuracy were calculated, and receiver operating characteristic analysis was performed, comparing with elastograms and B-mode images, with histological findings as the reference standard.

RESULTS

Sensitivity, specificity, and accuracy of elastography were 100, 71, and 90 %, respectively, with an ES cutoff value of 3; 92, 100, and 95 % for elastography with an ES cutoff value of 4; and 77, 57, and 70 % for B-mode ultrasound.

CONCLUSION

Elastography can enhance the diagnostic accuracy of ultrasound for differentiating between reactive and malignant lymph nodes in CMM and might eliminate the need for sentinel lymph node biopsy. The optimum ES cutoff value for reactive versus metastatic lymph nodes is 4.

Accuracy of axillary lymph node staging in breast cancer patients: an observer-performance study comparison of MRI and ultrasound

PURPOSE

To compare magnetic resonance imaging (MRI) and ultrasound (US) for axillary lymph node (LN) staging in breast cancer patients in an observer-performance study.

MATERIALS AND METHODS

An observer-performance study was conducted with five breast radiologists reviewing 50 consecutive patients of newly diagnosed invasive breast cancer with the use of ipsilateral axillary MRI and US. LN status was pathologically proved in all patients. Each observer reviewed the images in two separate sessions: one for MRI and the other for US. Observers were asked to indicate their confidence of the presence of at least one ipsilateral metastatic LN on a quasi-continuous rating scale and whether they recommend percutaneous biopsy preoperatively. Receiver operating characteristic (ROC) analysis and area under the ROC curve were used to characterize diagnostic performance. Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated from whether observers recommended biopsy.

RESULTS

There were no statistically significant differences in each observer's performance between MRI and US, or in the performance of all observers as a group, in terms of ROC analysis. There were no statistically significant differences in sensitivity, specificity, PPV, or NPV between MRI and US, but there were statistically significant improvements in specificity and PPV from either MRI or US alone to MRI and US combined.

CONCLUSIONS

Observer performance on MRI and US are comparable for axillary LN staging. When US and MRI are concordant for positive findings, higher specificity and PPV can be obtained.

Is imaging the future of axillary staging in breast cancer?

Axillary management in patients with breast cancer has become much less invasive with the introduction of sentinel lymph node biopsy (SLNB). However, over 70 % of SLNBs are negative, questioning the generic use of this invasive procedure. Emerging evidence indicates that breast cancer patients with a low axillary burden of disease do not benefit from axillary lymph node dissection (ALND). Non-invasive techniques such as paramagnetic iron oxide contrast-enhanced magnetic resonance imaging (MRI) may provide genuine alternatives to axillary staging and should be evaluated within clinical trials. Selective axillary surgery could then be offered based on imaging findings and for therapeutic intent. This non-operative approach would reduce morbidity further and facilitate interpretation of follow-up imaging. Key Points • Modern imaging and biopsy greatly help the axillary staging of breast cancer. • Superparamagnetic iron oxide (SPIO)-enhanced MRI offers a further advance. • Sentinel lymph node biopsy may become redundant with SPIO-enhanced MRI. • Selective therapeutic axillary surgery should be based upon preoperative imaging findings.

New ultrasound techniques for lymph node evaluation

Conventional ultrasound (US) is the recommended imaging method for lymph node (LN) diseases with the advantages of high resolution, real time evaluation and relative low costs. Current indications of transcutaneous ultrasound and endoscopic ultrasound include the detection and characterization of lymph nodes and the guidance for LN biopsy. Recent advances in US technology, such as contrast enhanced ultrasound (CEUS), contrast enhanced endoscopic ultrasound (CE-EUS), and real time elastography show potential to improve the accuracy of US for the differential diagnosis of benign and malignant lymph nodes. In addition, CEUS and CE-EUS have been also used for the guidance of fine needle aspiration and assessment of treatment response. Complementary to size criteria, CEUS could also be used to evaluate response of tumor angiogenesis to anti-angiogenic therapies. In this paper we review current literature regarding evaluation of lymphadenopathy by new and innovative US techniques.

Ultrasound elastography in the head and neck. Part II. Accuracy for malignancy

Ultrasound elastography (USE) describes a variety of ultrasound-based imaging techniques that measure tissue stiffness properties, and is currently under intense investigation for tissue characterization in several anatomic sites. This article summarizes the evidence regarding the accuracy of USE for malignancy in the head and neck. Currently, most published data pertains to small pilot studies with varied methodologies. Encouragingly, most studies have documented promising results for USE in terms of high accuracy for malignancy in thyroid nodules and cervical lymph nodes, which have surpassed conventional sonographic criteria. However, a minority of studies have documented opposite findings. USE seems to be suboptimal for salivary malignancies, and some evidence suggests that USE does not provide useful diagnostic information compared with conventional ultrasonography for miscellaneous neck masses. Further larger studies are required to validate these findings although, in view of the predominance of highly optimistic results for thyroid nodules and cervical lymph nodes, USE may become a useful ancillary technique in the routine diagnostic work-up of lesions in these tissues in the near future.

Sonographic elastography improves the sensitivity and specificity of axilla sampling in breast cancer: a prospective study

We describe a study to determine whether elastography of axillary lymph nodes (LNs) combined with B-mode ultrasound (US) is capable of differentiating the benign from the metastatic state in patients with breast cancer. B-mode US, elastography and fine-needle aspiration of 90 axillary lymph nodes from 89 female patients with breast cancer are described in this report. Five elastographic patterns were observed as defined by the percentages of high elasticity according to pattern of distribution and degree of hardness of the target LNs. B-mode US and elastography scores were combined to give the final scores. Sensitivity and specificity were 80% and 88%, respectively, for B-mode US alone, 86% and 90% for elastography alone and 84% and 98% for the combined assessment to differentiate the benign from the malignant state. The combination of B-mode US and elastography is capable of identifying metastatic axillary LNs from benign enlargement in patients with breast cancer.

Breast elastography: the technical process and its applications

Breast elastography is being increasingly used to better characterize breast lesions. Published studies have shown that it improved specificity of B mode ultrasound. Two elastography modes are available: free-hand elastography and shear wave elastography. Free-hand elastography is obtained by a mechanic wave induced by the ultrasound probe, deforming the target, either by small movements induced by breathe. An elastogram is obtained and displayed either as a colour map or a size ratio or elasticity ratio measurement. The second mode is shear wave elastography; two methods are available: Shear Wave Elastography (SWE) and ARFI mode (Acoustic Radiation Force Impulse). Shear wave elastography is less operator-dependent than free-hand elastography mode and provides a quantitative approach. A value of over 80kPa (SWE) or velocity results of over 2m/s (ARFI) are considered as suspicious. False negatives may occur in soft breast cancers (mucinous carcinoma, carcinoma with an inflammatory stroma, etc.) and false positives may be seen with poorly deformable benign lesions such as old fibrous adenomas. In practical use, elastography is a useful complementary tool for undetermined breast lesions categorized as BI-RADS 4a or BI-RADS 3, or for cystic lesions but cannot avoid fine needle aspiration or core biopsy if ultrasound features are clearly suspicious.

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

BACKGROUND

To 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.

METHODS

Axillary 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.

RESULTS

In 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%).

CONCLUSIONS

Sonoelastography 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.

In vivo classification of breast masses using features derived from axial-strain and axial-shear images

Breast cancer is currently the second leading cause of cancer deaths in women. Early detection and accurate classification of suspicious masses as benign or malignant is important for arriving at an appropriate treatment plan. In this article, we present classification results for features extracted from ultrasound-based, axial-strain and axial-shear images of breast masses. The breast-mass stiffness contrast, size ratio, and a normalized axial-shear strain area feature are evaluated for the classification of in vivo breast masses using a leave-one-out classifier. Radiofrequency echo data from 123 patients were acquired using Siemens Antares or Elegra clinical ultrasound systems during freehand palpation. Data from four different institutions were analyzed. Axial displacements and strains were estimated using a multilevel, pyramid-based two-dimensional cross-correlation algorithm, with final processing block dimensions of 0.385 mm × 0.507 mm (three A-lines). Since mass boundaries on B-mode images for 21 patients could not be delineated (isoechoic), the combined feature analysis was only performed for 102 patients. Results from receiver operating characteristic (ROC) demonstrate that the area under the curve was 0.90, 0.84, and 0.52 for the normalized axial-shear strain, size ratio, and stiffness contrast, respectively. When these three features were combined using a leave-one-out classifier and support vector machine approach, the overall area under the curve improved to 0.93.

Nanoparticle uptake in tumors is mediated by the interplay of vascular and collagen density with interstitial pressure

Nanoparticle delivery into solid tumors is affected by vessel density, interstitial fluid pressure (IFP) and collagen, as shown in this article by contrasting the in vivo macroscopic quantitative uptake of 40 nm fluorescent beads in three tumor types.The fluorescence uptake was quantified on individual animals by normalization with the transmitted light and then normalized to normal tissue uptake in each mouse. Mean data for uptake in individual tumor lines then showed expected trends with the largest uptake in the most vascularized tumor line. Tumor lines with increased collagen were also consistent with highest interstitial fluid pressure and correlated with lowest uptake of nanoparticles. The data is consistent with a delivery model indicating that while vascular permeability is maximized by neovascular growth, it is inhibited by collagen content and the resulting interstitial pressure. Imaging of these parameters in vivo can lead to better individual noninvasive methods to assess drug penetration in situ.

FROM THE CLINICAL EDITOR

In this manuscript the dependence of nanoparticle delivery is addressed from the standpoint of vascular factors (the more vascularized, the better delivery) and as a function of collagen density and interstitial pressure (the higher these are, the worse the delivery).

Rapid on-site evaluation of axillary fine-needle aspiration cytology in breast cancer

BACKGROUND

Axillary ultrasonography (AUS) and fine-needle aspiration cytology (FNAC) can establish axillary lymph node status before surgery, although this technique is hampered by poor adequacy rates. To achieve consistently high rates of FNAC adequacy, rapid on-site evaluation (ROSE) of FNAC samples was introduced.

METHODS

This single-centre, retrospective observational study of patients with newly diagnosed breast cancer undergoing preoperative AUS and FNAC between February 2008 and November 2010 examined the effect of the introduction of ROSE.

RESULTS

A total of 381 patients were included. AUS revealed 152 axillae with suspicious radiological features. FNAC was positive for malignant cells in 75 (49·3 per cent) of 152 samples. Sentinel lymph node mapping was avoided in 75 patients, representing 19·7 per cent of the entire study population. Adequacy rates increased from 78 per cent to 96 per cent following the introduction of ROSE (P = 0·001). The overall sensitivity and specificity of AUS and FNAC was 80·6 and 100 per cent respectively. A lymph node diameter equal to or larger than 10 mm and extranodal extension were significantly associated with positive FNAC (P < 0·001 and P = 0·012 respectively). Maximum lymph node diameter of at least 10 mm was an independent predictor of positive FNAC (odds ratio 11·2, 95 per cent confidence interval 3·32 to 37·76; P < 0·001).

CONCLUSION

AUS with FNAC provided accurate preoperative staging of the axilla for metastatic breast disease and avoided unnecessary sentinel lymph node mapping. The introduction of ROSE ensured the efficiency of AUS and FNAC.

Real-time elastography for the differentiation of benign and malignant superficial lymph nodes: a meta-analysis

BACKGROUND

Real-time elastography (RTE), as a non-invasive method, is used for the classification of benign and malignant lymph nodes (LNs) and developed as an alternative to biopsy. Elasticity score (ES) and strain ratio (SR) are used for the interpretation of RTE. We studied the performance of RTE for diagnosis of malignant LNs using meta-analysis.

METHODS

PubMed, the Cochrane Library, ISI Web of Knowledge, China National Knowledge Infrastructure were searched. The studies published in English or Chinese relating to the diagnostic value of RTE for superficial LNs were collected. Hierarchical summary receiver operating characteristic (HSROC) curve was used to examine the RTE accuracy. Clinical utility of RTE for LNs was evaluated by Fagan plot analysis.

RESULTS

A total of 9 studies which included 835 LNs were analyzed. The summary sensitivity and specificity for the diagnosis of malignant LNs were 0.74 (95% confidence interval (CI), 0.66-0.81) and 0.90 (95% CI, 0.82-0.94) for ES, and 0.88 (95% CI, 0.79-0.93) and 0.81 (95% CI, 0.49-0.95) for SR, respectively. Compared to ES, SR obviously improved the diagnostic sensitivity value. The HSROCs were 0.88 for ES and 0.91 for SR, respectively. After RTE results over the cut-off value for malignant LNs ("positive" result), the corresponding post-test probability for the presence (if pre-test probability was 50%) was 88% for ES and 82% for SR, respectively; while, in "negative" measurement, the post-test probability was 22% and 13%, respectively.

CONCLUSION

RTE has a high accuracy in the classification of superficial LNs and can potentially help to select suspicious LNs for biopsy.