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

Diagnostic value of multiple ultrasound diagnostic techniques for axillary lymph node metastases in breast cancer: A systematic analysis and network meta-analysis

Background

Early diagnosis of axillary lymph node metastasis is very important for the recurrence and prognosis of breast cancer. Currently, Lymph node biopsy is one of the important methods to detect lymph node metastasis in breast cancer, however, its invasiveness might bring complications to patients. Therefore, this study investigated the diagnostic performance of multiple ultrasound diagnostic methods for axillary lymph node metastasis of breast cancer.

Materials and methods

In this study, we searched PubMed, Web of Science, CNKI and Wan Fang databases, conducted Bayesian network meta-analysis (NMA) on the studies that met the inclusion criteria, and evaluated the consistency of five different ultrasound imaging techniques in axillary lymph node metastasis of breast cancer. Funnel graph was used to evaluate whether it had publication bias. The diagnostic performance of each ultrasound imaging method was ranked using SUCRA.

Results

A total of 22 papers were included, US+CEUS showed the highest SUCRA values in terms of sensitivity (SEN) (0.874), specificity (SPE) (0.911), positive predictive value (PPV) (0.972), negative predictive value (NPV) (0.872) and accuracy (ACC) (0.990).

Conclusion

In axillary lymph node metastasis of breast cancer, the US+CEUS combined diagnostic method showed the highest SUCRA value among the five ultrasound diagnostic methods. This study provides a theoretical basis for preoperative noninvasive evaluation of axillary lymph node metastases in breast cancer patients and clinical treatment decisions.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022351977.

Ultrasound guided needle biopsy of axilla to evaluate nodal metastasis after preoperative systemic therapy in cohort of 106 breast cancers enriched with BRCA1/2 pathogenic variant carriers

BACKGROUND

Aim of the study is to evaluate the role of ultrasound guided fine needle aspiration cytology (FNAC) in the restaging of node positive breast cancer after preoperative systemic therapy (PST).

METHODS

From January 2016 - October 2020 106 node positive stage IIA-IIIC breast cancer cases undergoing PST were included in the study. 18 (17 %) were carriers of pathogenic variant in BRCA1/2. After PST restaging of axilla was performed with ultrasound and FNAC of the marked and/or the most suspicious axillary node. In 72/106 cases axilla conserving surgery and in 34/106 cases axillary lymph node dissection (ALND) was performed.

RESULTS

False Positive Rate (FPR) of FNAC after PST in whole cohort and BRCA1/2 positive subgroup is 8 and 0 % and False Negative Rate (FNR) - 43 and 18 % respectively. Overall Sensitivity - 55 %, specificity- 93 %, accuracy 70 %.

CONCLUSION

FNAC after PST has low FPR and is useful to predict residual axillary disease and to streamline surgical decision making regarding ALND both in BRCA1/2 positive and negative subgroups. FNR is high in overall cohort and FNAC alone are not able to predict ypCR and omission of further axillary surgery. However, FNAC performance in BRCA1/2 positive subgroup is more promising and further research with larger number of cases is necessary to confirm the results.

Ultrasonographic Algorithm for the Assessment of Sentinel Lymph Nodes That Drain the Mammary Carcinomas in Female Dogs

The status of sentinel lymph nodes (SLNs) is decisive in staging, prognosis, and therapeutic approach. Using an ultrasonographic examination algorithm composed of B-mode, Doppler technique, contrast-enhanced ultrasound (CEUS) and elastography, this study aimed to determine the diagnostic performance of the four techniques compared to histopathological examination. 96 SLNs belonging to 71 female dogs with mammary gland carcinomas were examined. After examinations, mastectomy and lymphadenectomy were performed. Histopathological examination confirmed the presence of metastases in 54 SLNs. The elasticity score had the highest accuracy-89.71%, identifying metastases in SLNs with 88.9.9% sensitivity (SE) and 90.5% specificity (SP), ROC analysis providing excellent results. The S/L (short axis/long axis) ratio showed 83.3% SE and 78.6% SP as a predictor of the presence of metastases in SLN having a good accuracy of 81.2%. On Doppler examination, the resistivity index(RI) showed good accuracy of 80% in characterizing lymph nodes with metastases versus unaffected ones; the same results being obtained by CEUS examination. By assigning to each ultrasonographic parameter a score (0 or 1) and summing up the scores of the four techniques, we obtained the best diagnostic performance in identifying lymph node metastases with 92.2% accuracy. In conclusion, the use of the presented algorithm provides the best identification of metastases in SLNs, helping in mammary carcinoma staging and appropriate therapeutic management.

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.

Semi-quantitative strain elastography may facilitate pre-surgical prediction of mandibular lymph nodes malignancy in dogs

Evaluation of mandibular lymph nodes in a patient with head and neck cancer is important for stage determination and prognosis development, and, in human medicine, the use of sonoelastography for differentiating between non-metastatic and metastatic lymph nodes has been reported. Our prospective, cross-sectional study aimed to evaluate the diagnostic performance of strain elastography and to determine elastographic cut-off values for predicting malignancy. Sixty-six mandibular lymph nodes were included (clinical healthy, n = 45; non-metastatic, n = 8; and metastatic, n = 13). Elastographic images were evaluated qualitatively (elastographic pattern) and semi-quantitatively (mean hue histogram and stiffness area ratios). Elastographic patterns were classified as grades 1 to 4, according to the percentage of high elasticity determined by visualization. The mean hue histogram was defined based on as the mean pixel color values within the lymph node. Stiffness area ratios were determined by computer program analysis of the stiff area. Among the criteria, receiver operating characteristic curve analyses revealed cut-off values for the prediction of malignancy of 92.26 for mean hue histogram (sensitivity: 100%, specificity: 92%), and 0.17 for stiffness area ratios (sensitivity: 86%, specificity of 100%). Reproducibility and repeatability were excellent. In conclusion, semi-quantitative evaluation via strain elastography holds potential for predicting lymph node malignancy.

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.

Handheld optical palpation of turbid tissue with motion-artifact correction

Handheld imaging probes are needed to extend the clinical translation of optical elastography to in vivo applications, yet such probes have received little attention. In this paper, we present the first demonstration of optical palpation using a handheld probe. Optical palpation is a variant of optical elastography that uses three-dimensional optical coherence tomography (3D-OCT) to provide maps of stress at the tissue surface under static compression. Using this technique, stiff features present beneath the surface of turbid tissues are identified, providing mechanical contrast complementary to the optical contrast provided by OCT. However, during handheld operation, relative motion between the probe and the tissue can induce motion artifact, causing spatial distortion of 3D-OCT and in turn, optical palpation images. We overcome this issue using a novel, dual-function bi-layer that provides both a fiducial marker for co-registration and a compliant section for estimation of the stress at the tissue surface. Co-registration of digital photographs of the bi-layer laid out over the tissue surface is used to measure and correct for motion in the lateral (xy) plane. We also demonstrate, for the first time, that optical palpation can be used as a method for monitoring pressure applied to the tissue during handheld operation, thus providing a more repeatable and robust imaging technique between different users. Handheld optical palpation is demonstrated on a structured phantom, in vivo human skin and excised human breast tissue. In each case, image quality comparable to bench-top 3D-OCT and optical palpation is achieved.

Ultrasonography for lymph nodes metastasis identification in bitches with mammary neoplasms

The aim of this study was to evaluate and compare the diagnostic accuracy of B-mode, Doppler ultrasonography and Acoustic Radiation Force Impulse (ARFI) elastography in the identification of axillary and inguinal lymph nodes metastasis in bitches with mammary neoplasms. The axillary (n = 96) and inguinal (n = 100) lymph nodes of 100 bitches were evaluated using B-Mode, Colour Doppler and ARFI-elastography. After this evaluation, mastectomy and lymph nodes excision were performed and these structures were histologically classified as free, reactive or metastatic. Ultrasonographic parameters were compared by Chi-Square or ANOVA tests and if they are significant, discriminative power analysis according to histopathological classification was performed (ROC analysis). The ARFI-elastography shear wave velocity (SWV) enabled metastasis identification in inguinal (sensitivity 95% specificity 87%) and axillary lymph nodes (sensitivity 100% specificity 94%). While B-Mode ultrasound Short/Long axis ratio evaluation of inguinal and axillary lymph nodes only resulted in a sensitivity around of 71% and specificity of 55%. In conclusion, B-Mode ultrasonography may contribute to diagnosis of metastasis in axillary and inguinal lymph nodes of bitches affected by mammary neoplasm with limited accuracy, while SWV evaluation proved to be an excellent diagnosis tool, which allows differentiation between free, reactive and tumour metastatic lymph nodes.

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.

Strain Elastography - How To Do It?

Tissue stiffness assessed by palpation for diagnosing pathology has been used for thousands of years. Ultrasound elastography has been developed more recently to display similar information on tissue stiffness as an image. There are two main types of ultrasound elastography, strain and shear wave. Strain elastography is a qualitative technique and provides information on the relative stiffness between one tissue and another. Shear wave elastography is a quantitative method and provides an estimated value of the tissue stiffness that can be expressed in either the shear wave speed through the tissues in meters/second, or converted to the Young's modulus making some assumptions and expressed in kPa. Each technique has its advantages and disadvantages and they are often complimentary to each other in clinical practice. This article reviews the principles, technique, and interpretation of strain elastography in various organs. It describes how to optimize technique, while pitfalls and artifacts are also discussed.

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.

Transthoracic Ultrasound Elastography in Pulmonary Lesions and Diseases

Ultrasound elastography has shown promising result in the diagnosis of various diseases; however, its application for pulmonary diseases has yet to be clarified. This study aimed to assess the application and feasibility of ultrasound elastography in various pulmonary lesions and diseases. We enrolled 45 patients with radiographic evidence of pneumonia, tumors or obstructive pneumonitis, and 70 ultrasonic lesions were identified (eight necrosis, 17 atelectasis, seven consolidation and 38 tumors). Ultrasound elastography was performed and the strain ratio, which is the ratio of strain of the reference tissue to an equally measuring region of interest of a lesion, was measured. The strain ratio was significantly different among lesions with different ultrasound morphologies (1.03 ± 0.71 [necrosis] vs. 2.51 ± 1.14 [atelectasis] vs. 19.98 ± 15.59 [consolidation] vs. 36.19 ± 20.18 [tumor]; p < 0.05). The strain ratio of primary lung cancer was also significantly different from pneumonia (p = 0.023) and metastatic lung cancer (p = 0.015). In conclusion, transthoracic ultrasound elastography can differentiate pulmonary lesions with different ultrasound morphologies. ClinicalTrials.gov Identifier: NCT02636985.

Assessment of Ultrasound Features Predicting Axillary Nodal Metastasis in Breast Cancer: The Impact of Cortical Thickness

PURPOSE

To evaluate the accuracy of axillary ultrasound (AUS) in detecting nodal metastasis in patients with early-stage breast cancer and to identify AUS features with high predictive power.

MATERIALS AND METHODS

Prospective single-center preliminary study in 105 patients with a primary diagnosis of breast cancer and clinically negative axilla. AUS was performed using a 12 MHz linear-array transducer before ultrasound-guided needle biopsy. Nodal characteristics (shape, longitudinal-transverse [LT] axis ratio, margins, cortical thickness, hyperechoic hilum) were correlated with histopathological nodal status after SLNB or axillary lymph node dissection (ALND).

RESULTS

Nodal metastases were present in 42/105 patients (40.0%). Univariate analyses showed that absence of hyperechoic hilum, round shape, LT axis ratio<2, sharp margins and cortical thickness>3 mm were associated with lymph node metastasis. Multivariate logistic regression analysis revealed cortical thickness > 3 mm as an independent predictive parameter for nodal involvement. Sensitivity, specificity, positive predictive value, negative predictive value and accuracy were 66.7, 74.6, 63.6, 77.0% and 71.4% respectively when cortical thickness > 3 mm was applied as the criterion for AUS positivity. Axillary tumor volume was low in patients with pT1/2 tumors and negative AUS, since only 3.2% of patients had > 2 metastatic lymph nodes.

CONCLUSION

Cortical thickness>3 mm is a reliable predictor of nodal metastatic involvement. Negative AUS does not exclude lymph node metastases, but extensive axillary tumor volume is rare.

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.

Feasibility and reproducibility of ShearWave(TM) elastography of fetal baboon organs

OBJECTIVES

The purpose of this study was to assess the feasibility and reproducibility of transabdominal ShearWave(TM) elastography of fetal organs in pregnant baboons.

MATERIALS AND METHODS

Fetal ultrasounds of all pregnant baboons in a single primate research center were performed prospectively during 9 months. The visualization of fetal targeted organs (liver, proximal and distal lungs, brain white matter and periventricular gray matter) was initially performed using 2D ultrasound, and then elastography mode was activated. For each organ, three measurements were carried out by two operators. Intra-observer and inter-observer intra-class correlation coefficients (ICC) were calculated.

RESULTS

During the study period (03/2013-12/2013), 21 pregnant baboons (21 fetuses) were included. One to three ultrasound scans were performed for each fetus. The measurements were feasible by the two operators in all cases. The intra-observer and inter-observer ICC were 0.654, 95% CI (0.606 to 0.699) and 0.645, 95% CI (0.553 to 0.721) respectively.

CONCLUSION

Transabdominal ShearWave(TM) Elastography of fetal organs can be achieved in pregnant baboons. The intra-observer and inter-observer reproducibility is correct but vary according to the targeted organs.

[Shear waves elastography of the placenta in pregnant baboon]

OBJECTIVES

To evaluate tissue characteristics of the placenta by transabdominal ShearWave Elastography in pregnant baboon.

MATERIALS AND METHOD

For 9 months (03/2013-12/2013) two operators (EQ, GG) performed ultrasound of the placenta during pregnancy pregnant baboons station partner primatology project. The identification of the placenta was performed previously in 2D ultrasound. The elastography method was then activated. Three measurements were carried out by operator for each placenta. The intraclass correlation coefficients within and between observers were calculated for the objective assessment (elastography) of placental maturity.

RESULTS

During the study period, 21 pregnant baboons were included and ultrasounds were performed between 1 and 3 times each. The measurements have been carried out by two operators in 100% of cases. The intra- and inter-observer ICC for single values are respectively 0.657 - 95% CI (0.548 to 0.752) and 0.458 - 95% CI (0.167 to 0.675). The intra- and inter-observer ICC for average values are respectively 0.852 - 95% CI (0.784 to 0.901) and 0.628 - 95% CI (0.286 to 0.806).

CONCLUSION

The study by transabdominal ShearWave Elastography of placenta's pregnant baboons is possible. The intra- and inter-operator reproducibility of this method is good using the average of three measurements. The objective study via elastography ShearWave of the degree of placental maturity seems not yet be used in clinical practice. Studies of larger cohorts are needed.

Quantitative elastography of the uterine cervix as a predictor of preterm delivery

OBJECTIVE

To evaluate the correlation between preterm delivery before 37 weeks of gestation and ultrasound elastography strain measurement of cervical stiffness.

STUDY DESIGN

In this prospective study, 182 pregnant women were examined vaginally by ultrasound elastography from a mid-sagittal plane. Cervical length was measured and strain was calculated in four regions of interest on the anterior cervical lip. First, the software was validated by intraobserver variability. Second, strain and strain ratios were calculated with adjusted software presets and correlated to the outcome of spontaneous preterm delivery (sPTD).

RESULT

A total of 8928 regions of interest (ROIs) and 6696 ratios were evaluated. The median gestational age at examination was 26 ± 6.1 weeks. A median maternal age of 33 ± 5.6 and a medial parity of 1 ± 0.9 were observed. Intra-Class-Correlation values in validation phase ranged from 0.893 to 0.967. The prevalence of sPTD was 11.9%. Strain ratio Rselective was identified as the best predictor of preterm delivery. Rselective values >0.89 were associated with preterm delivery with a sensitivity of 0.59 and a specificity of 0.86 (odds ratio=1.474 for an increase of 0.1 in Rselective; P=0.002).

CONCLUSION

Ultrasound elastography strain measurement of cervical stiffness is correlated with the predictability of preterm delivery.

Evidence that breast tissue stiffness is associated with risk of breast cancer

Background

Evidence from animal models shows that tissue stiffness increases the invasion and progression of cancers, including mammary cancer. We here use measurements of the volume and the projected area of the compressed breast during mammography to derive estimates of breast tissue stiffness and examine the relationship of stiffness to risk of breast cancer.

Methods

Mammograms were used to measure the volume and projected areas of total and radiologically dense breast tissue in the unaffected breasts of 362 women with newly diagnosed breast cancer (cases) and 656 women of the same age who did not have breast cancer (controls). Measures of breast tissue volume and the projected area of the compressed breast during mammography were used to calculate the deformation of the breast during compression and, with the recorded compression force, to estimate the stiffness of breast tissue. Stiffness was compared in cases and controls, and associations with breast cancer risk examined after adjustment for other risk factors.

Results

After adjustment for percent mammographic density by area measurements, and other risk factors, our estimate of breast tissue stiffness was significantly associated with breast cancer (odds ratio = 1.21, 95% confidence interval = 1.03, 1.43, p = 0.02) and improved breast cancer risk prediction in models with percent mammographic density, by both area and volume measurements.

Conclusion

An estimate of breast tissue stiffness was associated with breast cancer risk and improved risk prediction based on mammographic measures and other risk factors. Stiffness may provide an additional mechanism by which breast tissue composition is associated with risk of breast cancer and merits examination using more direct methods of measurement.

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.

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.