Detecting metastasis of lymph nodes and predicting aggressiveness in patients with breast carcinomas

Diagnostic efficacy of sentinel lymph node in breast cancer under percutaneous contrast-enhanced ultrasound: An updated meta-analysis

Background

To investigate the diagnostic efficacy of sentinel lymph nodes (SLN) in breast cancer by percutaneous contrast‐enhanced ultrasound (CEUS) through pooled analysis of relevant studies published before June 2021.

Methods

We conducted a systematic review and meta‐analysis of relevant studies by searching the electronic databases of PubMed, Embase, Cochrane Library, Chinese National Knowledge Infrastructure, Wanfang and VIP and the studies were screened according to their inclusion and exclusion criteria. Sensitivity (SEN), specificity (SPE), positive likelihood ratio (+LR), negative likelihood ratio (−LR) and diagnostic odds ratio (DOR) were calculated by Meta‐disc 1.4 software and the summary receiver operating characteristic (SROC) curve and area under the curve of ROC (AUC) were constructed.

Results

Twenty‐two publications evaluating the diagnostic efficacy of SLN in breast cancer under percutaneous CEUS were included in the meta‐analysis. The diagnostic sensitivity, specificity were 0.86 (95% CI: 0.83–0.88) and 0.89 (95% CI: 0.87–0.91) for SLN in breast cancer detected by percutaneous CEUS respectively using a random effect model. The +LR and –LR were combined in a random effect model due to significant statistical heterogeneity (p < 0.05). The pooled +LR, −LR were 7.06 (95% CI: 4.34–11.50), and 0.17 (95% CI: 0.12–0.24), respectively. The combined DOR was 53.32 (95% CI: 29.74–95.61) for SLN diagnosis in breast cancer by percutaneous CEUS under a random effect model. The AUC was 0.94 which indicated that CEUS had high diagnostic efficacy of SLN in patients with breast cancer.

Conclusions

CEUS is a noninvasive method for the detection SLN in patients of breast cancer with relative high prediction efficacy.

Oncologic Imaging of the Lymphatic System: Current Perspective with Multi-Modality Imaging and New Horizon

The lymphatic system is an anatomically complex vascular network that is responsible for interstitial fluid homeostasis, transport of large interstitial particles and cells, immunity, and lipid absorption in the gastrointestinal tract. This network of specially adapted vessels and lymphoid tissue provides a major pathway for metastatic spread. Many malignancies produce vascular endothelial factors that induce tumoral and peritumoral lymphangiogenesis, increasing the likelihood for lymphatic spread. Radiologic evaluation for disease staging is the cornerstone of oncologic patient treatment and management. Multiple imaging modalities are available to access both local and distant metastasis. In this manuscript, we review the anatomy, physiology, and imaging of the lymphatic system.

Contrast-Enhanced Ultrasound in Locating Axillary Sentinel Lymph Nodes in Patients with Breast Cancer: A Prospective Study

The objective was to explore the clinical value of contrast-enhanced ultrasound (CEUS) in locating the sentinel lymph node (SLN) in patients with early breast cancer. We screened 143 consecutive patients with breast cancer between July 2017 and August 2019. The number of SLNs identified by CEUS and dual labeling (blue dye and radiolabeled colloid) were recorded. The accuracy of CEUS plus fine-needle aspiration cytology (FNAC) was assessed. The rate of identification of SLNs with CEUS was 84.0% (121/144), and that of dual labeling was 97.92% (141/144). There was no significant association between non-enhancement (p = 0.060) or inhomogeneous enhancement (p = 0.468) and lymph node metastasis. The sensitivity and specificity of CEUS-SLNs plus FNAC was 78.38% and 100%, respectively. The technique of CEUS is a promising method for locating the axillary SLN. But it is hard to identify lymph node metastasis with CEUS alone. CEUS-SLNs plus FNAC is a sound technique for diagnosis of the metastasis of SLN.

Clinical Utility of Contrast-enhanced Ultrasound for the Diagnosis of Lymphadenopathy

This meta-analysis aimed to evaluate the diagnostic accuracy of contrast-enhanced ultrasonography (CEUS) in identifying lymphazdenopathy. PubMed, Web of Science, Embase and the Cochrane Library were searched for relevant articles through September 2020. A total of 16 articles, which included 1787 participants, were analyzed. The summary sensitivity, specificity, positive likelihood ratio (LR), negative LR and diagnostic odds ratio of CEUS for diagnosing lymphadenopathy were 0.88 (0.86-0.90), 0.90 (0.88-0.92), 6.04 (3.67-9.95), 0.15 (0.10-0.21) and 47.38 (23.45-95.66), respectively. The summary receiver operating characteristic (SROC) area under the curve (AUC) was 0.9405. After omitting outliers identified in a bivariate box plot and forest plot, heterogeneity was decreased, and the pooled sensitivity and specificity were 0.87 (0.84-0.90) and 0.87 (0.84-0.90), respectively. Furthermore, the SROC AUC was 0.9327. In conclusion, CEUS has the potential to be a valuable tool for characterizing lymphadenopathy and could provide clinical decision support.

Adding contrast-enhanced ultrasound markers to conventional axillary ultrasound improves specificity for predicting axillary lymph node metastasis in patients with breast cancer

OBJECTIVE

To evaluate the diagnostic performance of contrast-enhanced ultrasound (CEUS) combined with conventional ultrasound of axillary lymph nodes (ALNs) in predicting metastatic ALNs in patients with breast cancer.

METHODS

This retrospective study included 259 patients with breast cancer who underwent conventional ultrasound and CEUS. The parameters and patterns evaluated on conventional ultrasound included short axis diameter (S), long axis/short axis (L/S) ratio, cortical thickness, resistive index (RI), lymph node (LN) morphology of greyscale ultrasound, hilum and vascular pattern. Meanwhile, enhancement pattern, wash-in time, time to peak (TP), maximum signal intensity, and duration of contrast enhancement were evaluated on CEUS. Univariate and multiple logistic regression analyses were performed to identify independent factors of ALN status. Three models (conventional ultrasound, CEUS, and combined parameters) were established. Receiver operating characteristic (ROC) curves were applied to evaluate the accuracy of the three predictive models.

RESULTS

On conventional axillary ultrasound, LN morphology and vascular pattern were independent factors in predicting metastatic ALNs. On CEUS, maximum signal intensity, duration of contrast enhancement, and TP were independent factors in predicting metastatic ALNs. When combining conventional ultrasound and CEUS features, five independent factors obtained from the conventional ultrasound and CEUS were associated with ALN status. ROC curve analysis showed that the use of CEUS markers combined with conventional ultrasound features (AUC = 0.965) was superior to the use of CEUS markers (AUC = 0.936) and conventional ultrasound features alone (AUC = 0.851).

CONCLUSION

Combining conventional ultrasound and CEUS features can enable discrimination of ALN status better than the use of CEUS and conventional ultrasound features alone.

ADVANCES IN KNOWLEDGE

The axillary lymph node status in breast cancer patients impacts the treatment decision. Our ultrasonic data demonstrated that CEUS features of ALNs in breast cancer patients could be image markers for predicting ALN status. Combining conventional ultrasound and CEUS features of ALNs can improve specificity discrimination of ALN status better than the use of CEUS and the conventional ultrasound features alone, which will help the treatment planning optimization.

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.

Role of Contrast-Enhanced Ultrasound (CEUS) in the Diagnosis of Cervical Lymph Node Metastasis in Nasopharyngeal Carcinoma (NPC) Patients

Objective: The aim of the study was to evaluate the diagnostic value of contrast-enhanced ultrasound (CEUS) in distinguishing between benign and malignant cervical lymph nodes in patients with nasopharyngeal carcinoma (NPC).

Material and Methods: A total of 144 NPC patients with enlarged superficial cervical lymph nodes underwent CEUS examination. The comparison of CEUS image characteristics between malignant and benign cervical lymph nodes was performed in this study as well. We analyzed parameters of the time–intensity curve (TIC), which includes time to peak (TP), area under the gamma curve (AUC), and peak intensity (PI). Furthermore, receiver operating characteristic (ROC) curve analysis was also investigated to evaluate the diagnostic value of CEUS.

Result: We conducted 144 lymph node examinations in total, where 64 cases were biopsy-proven benign nodules and 80 cases were biopsy-proven metastatic nodules. The vast majority of the benign nodes displayed centrifugal perfusion (96.88%, 62/64) and homogeneous enhancement (93.75%, 60/64), while most of the malignant nodes showed centripetal perfusion (92.50%, 74/80) and inhomogeneous 80.00% (64/80). In addition, quantitative analysis showed that CEUS parameters including PI, TP, and AUC in benign lymph nodes (12.51 ± 2.15, 23.79 ± 11.80, and 1110.33 ± 286.17, respectively) were significantly higher than that in the malignant nodes (10.51 ± 2.98, 16.52 ± 6.95, and 784.09 ± 340.24, respectively). The assistance of the three aforementioned parameters and CEUS image characteristics would result in an acceptable diagnostic value.

Conclusion: Our results suggest that imaging perfusion patterns as well as quantitative parameters obtained from CEUS provide valuable information for the evaluation of cervical lymph nodes in NPC patients.

Performance of Molecular Lymphosonography for Detection and Quantification of Metastatic Involvement in Sentinel Lymph Nodes

OBJECTIVES

To assess the performance of molecular lymphosonography with dual-targeted microbubbles in detecting and quantifying the metastatic involvement in sentinel lymph nodes (SLNs) using a swine melanoma model.

METHODS

Targeted microbubbles were labeled with P-selectin and αV β3 -integrin antibodies. Control microbubbles were labeled with immunoglobulin G antibodies. First lymphosonography with Sonazoid (GE Healthcare, Oslo, Norway) was used to identify SLNs. Then dual-targeted and control microbubbles were injected intravenously to detect and quantify metastatic disease in the SLNs. Distant non-SLNs were imaged as benign controls. All evaluated lymph nodes (LNs) were surgically removed, and metastatic involvement was characterized by a histopathologic analysis. Two radiologists blinded to histopathologic results assessed the baseline B-mode images of LNs, and the results were compared to the histologic reference standard. The mean intensities of targeted and control microbubbles within the examined LNs were measured and compared to the LN histologic results.

RESULTS

Thirty-five SLNs and 34 non-SLNs from 13 Sinclair swine were included in this study. Twenty-one SLNs (62%) were malignant, whereas 100% of non-SLNs were benign. The sensitivity of B-mode imaging for metastatic LN diagnosis for both readers was relatively high (90% and 71%), but the specificity was very poor (50% and 58%). The sensitivity and specificity of molecular lymphosonography for metastatic LN detection were 91% and 67%, respectively. The mean intensities from dual-targeted microbubbles correlated well with the degree of metastatic LN involvement (r = 0.6; P < 0.001).

CONCLUSIONS

Molecular lymphosonography can increase the specificity of metastatic LN detection and provide a measure to quantify the degree of metastatic involvement.

Contrast-enhanced ultrasound for the differential diagnosis between benign and metastatic superficial lymph nodes: a meta-analysis

Purpose

Contrast-enhanced ultrasound (CEUS) is a new technique used to distinguish benign from metastatic superficial lymph nodes (LNs) with variable accuracy. The objective of this meta-analysis was to evaluate the accuracy of CEUS for the diagnosis of superficial metastatic LNs.

Methods

A comprehensive literature search of PubMed, Web of Science, Medline, Embase, and the Cochrane Library was performed until April 2018. Nine articles reporting the diagnosis of 436 LNs by CEUS were investigated. The Mantel–Haenszel and DerSimonian–Laird methods were used to analyze pooled sensitivity, specificity, diagnostic OR, positive likelihood ratio (LR), and negative LR, and a summary receiver operating characteristic (SROC) curve was also evaluated.

Results

The pooled sensitivity and specificity of CEUS for the differential diagnosis of benign and metastatic superficial LNs were 0.88 (95% CI, 0.83–0.92) and 0.80 (95% CI, 0.74–0.85), respectively. The pooled positive LR, negative LR, and diagnostic OR were 4.36 (95% CI, 2.38–7.99), 0.17 (95% CI, 0.10–0.31), and 32.75 (95% CI, 11.08–96.84), respectively. SROC area under the curve (AUC) was 0.9288. The subgroup analysis excluding outliers implied that the heterogeneity was almost eliminated, and the pooled sensitivity and specificity were 0.87 (95% CI, 0.81–0.92) and 0.79 (95% CI, 0.71–0.85), respectively. The SROC AUC was 0.8950.

Conclusion

CEUS, a novel imaging modality for the characterization of superficial LNs, shows a high sensitivity and specificity in the diagnosis of superficial metastatic LNs. The different diagnostic standards, contrast agents, and contrast modes contribute to a considerable level of heterogeneity among studies. A uniform standard for distinguishing between benign and metastatic LNs is needed for further clinical application.

Pre-operative and intra-operative detection of axillary lymph node metastases in 108 patients with invasive lobular breast cancer undergoing mastectomy

BACKGROUND

Despite the recent changes in the treatment of the axilla in selected breast cancer patient, positive sentinel lymph node (SLN) in patients undergoing mastectomy still necessitates axillary lymph node dissection (ALND). In invasive lobular carcinoma (ILC), pre-operative detection of the lymph node metastasis may be demanding due to its unique morphology. The aim of this study was to examine the benefit of preoperative axillary ultrasound (AUS), ultrasound-guided fine-needle aspiration biopsy (US-FNAB), and intra-operative imprint cytology (IIC), in order to avoid two-stage axillary surgery in patients with ILC undergoing mastectomy.

METHODS

The object of this study were 102 patients (median age 52, range 34-73 years) with clinically non-suspicious axilla in whom 108 mastectomies were performed after a pre-operative AUS investigation. Whenever a metastasis was detected in a sentinel lymph node, ALND was done. Reports of the pre-operative AUS investigation, US-FNAB, and IIC were compared with definitive histopathological reports of surgical specimens.

RESULTS

In 46 cases lymph node metastases were diagnosed. AUS suspicious lymph nodes were found in 29/108 cases and histopathology confirmed metastases in 22/30 cases. US-FNAB was performed in 29 cases with AUS suspicious lymph nodes. Cytology proved metastases in 11/29 cases. Histopathology confirmed metastases in 10/11 cases with only isolated tumor cells found in one case. IIC investigation was performed in 63 cases and in 10/27 cases metastases were confirmed by histopathology. Pre-operative AUS, US-FNAB, and/or IIC investigation enabled ALND during a single surgical procedure in 20/46 patients with metastases in lymph nodes.

CONCLUSION

Pre-operative AUS, US-FNAB, and/or IIC are/is beneficial in patients with ILC planned for mastectomy in order to decrease the number of two stage axillary procedures.

Analysis of Contrast-Enhanced Ultrasound Perfusion Patterns and Time-Intensity Curves for Metastatic Lymph Nodes From Lung Cancer: Preliminary Results

OBJECTIVES

To retrospectively summarize the similarities and differences in contrast-enhanced ultrasound (US) findings for lymph node metastasis from adenocarcinoma, squamous carcinoma, and small cell lung cancer.

METHODS

Patients who had received contrast-enhanced US examinations and had a histologic diagnosis of supraclavicular lymph node metastasis from lung cancer were included. The perfusion patterns on contrast-enhanced US images and time-intensity curve parameters were analyzed for the different pathologic types. The microvascular density and microvascular diameter were evaluated.

RESULTS

Totally, 61 patients were enrolled in this study, including 26 cases with lung squamous carcinoma, 26 with lung adenocarcinoma, and 9 with small cell lung cancer. Contrast-enhanced US perfusion showed no significant differences in enhancement uniformity during the arterial phase and in the presence of unenhanced areas of metastatic lymph nodes with the 3 different pathologic origins (P > .05), but fewer unenhanced areas could be seen in metastatic lymph nodes from adenocarcinoma. The analysis of the time-intensity curve parameters showed that there were significant differences in the peak intensity between metastatic lymph nodes from lung squamous carcinoma and lung adenocarcinoma (P < .05). The microvascular density of metastatic lymph nodes from adenocarcinoma was significantly higher than that of metastatic lymph nodes from squamous carcinoma and small cell lung cancer (P < .001; P = .0444), whereas the microvascular diameter of metastatic lymph nodes from adenocarcinoma was significantly smaller than that from squamous carcinoma and small cell lung cancer (P = .0277; P < .001).

CONCLUSIONS

Effects of the pathologic diagnosis should be considered when analyzing quantitative parameters of metastatic lymph nodes during contrast-enhanced US examinations, even in the same organ.

The role of CEUS in characterization of superficial lymph nodes: a single center prospective study

Accurate lymph node characterization is important in a large number of clinical settings. We evaluated the usefulness of Contrast Enhanced Ultrasound (CEUS) in distinguishing between benign and malignant lymph nodes compared with conventional ultrasonography in the differential diagnosis of superficial lymphadenopathy.

We present our experience for 111 patients enrolled in a single center.

111 superficial lymph nodes were selected and only 1 lymph node per patient underwent CEUS. A definitive diagnosis for all lymph nodes was obtained by ultrasonographically guided biopsy and/or excision biopsy.

The size of the lymph nodes, the site (neck, axilla, inguinal region) being easily accessible for biopsy, and the US and color Doppler US characteristics guided us in selecting the nodes to be evaluated by CEUS.

In our study we identified different enhancement patterns in benign and malignant lymph nodes, with a high degree of diagnostic accuracy for superficial lymphadenopathy in comparison with conventional US.

Role of Contrast-Enhanced Sonography in the Evaluation of Axillary Lymph Nodes in Breast Carcinoma: A Monocentric Study

OBJECTIVES

To evaluate the diagnostic performance of contrast-enhanced sonography for characterization of the lymph node status (metastatic or not) in patients with breast carcinomas by comparison with sentinel lymph node biopsy.

METHODS

From January to August 2015, 50 female patients with a histologic diagnosis of invasive breast carcinoma were prospectively examined by ipsilateral axillary contrast-enhanced sonography. The test was performed by a single radiologist using an ultrasound system with a broadband 8-12-MHz, 38-mm high-resolution linear transducer. For the target lymph node, we chose a node with a sonographic pattern that was suspicious for malignancy: ie, a longitudinal-to-transverse diameter ratio of less than 2, absence of a central hyperechogenic hilum, or both. In cases with a lack of sonographic signs of malignancy, we evaluated the node with the maximal transverse diameter. Nodes were considered malignant in cases with total absence of contrast enhancement and in those with enhancement alterations. Within 1 week, all patients underwent sentinel lymph node biopsy, followed by a histologic test.

RESULTS

The histologic test showed benignity in 22 of 50 sentinel lymph nodes, whereas 28 were metastatic. Among the 22 patients with negative biopsy results, contrast-enhanced sonography showed 18 concordances and 4 false-positives results; among the 28 with positive biopsy results, contrast-enhanced sonography obtained 100% correct characterizations of the axillary status. The sensitivity, specificity, and accuracy were 100%, 82%, and 92%, respectively.

CONCLUSIONS

Contrast-enhanced sonography appears to be a method with high accuracy for characterization of axillary lymph nodes, very close to the reference-standard sentinel lymph node biopsy. This technique seems to have overall high sensitivity.

Dynamic contrast-enhanced endoscopic ultrasound: A quantification method

Dynamic contrast-enhanced ultrasound (DCE-US) has been recently standardized by guidelines and recommendations. The European Federation of Societies for US in Medicine and Biology position paper describes the use for DCE-US. Comparatively, little is known about the use of contrast-enhanced endoscopic US (CE-EUS). This current paper reviews and discusses the clinical use of CE-EUS and DCE-US. The most important clinical use of DCE-US is the prediction of tumor response to new drugs against vascular angioneogenesis.

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.

Evaluation of Neck Lymph Node Metastasis on Contrast-Enhanced Ultrasound: An Animal Study

Objectives

To assess the performance of contrast-enhanced ultrasound (CEUS) intended to differentiate hyperplastic from malignant neck lymph nodes in an animal model.

Methods

Twenty-four New Zealand rabbits were randomly divided into two groups: neck lymph node metastasis group (12 rabbits) and reactive hyperplastic lymph node group (12 rabbits). Tongue VX2 carcinoma with cervical lymph node metastasis was induced in 12 rabbits by injecting VX2 carcinoma suspension into the left tongue submucosa. Hyperplastic neck lymph nodes were induced by injecting egg yolk in the submandibular region of the rabbits in hyperplastic group. CEUS were performed in both groups before and after intravenous administration of SonoVue. The site, number, echogenicity, longitudinal and transverse nodal dimensions, patterns of enhancement of the neck lymph nodes were observed and recorded.

Results

In both groups only one lymph node was found in the left (tumor) side of the neck. CEUS found 12 of 12 metastatic lymph nodes in metastasis group, and diagnosed 11 of 12 lymph nodes as metastatic. Histopathologic analysis revealed metastatic lesions in all 12 rabbits, each with one lymph node, and all 12 lymph nodes in hyperplastic group is inflammation lymph nodes. All 12 cases in the hyperplastic group showed centripetal homogeneous enhancement while in the metastasis group one case showed centripetal homogeneous enhancement, three cases showed centrifugal heterogeneous enhancement, and eight cases showed diffused heterogeneous enhancement. Only one lymph node was dissected on the left side of the neck in each rabbit in both groups.

Conclusion

CEUS can play a role in discriminating metastatic from hyperplastic lymph nodes in head and neck carcinoma.

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.

Contrast-Enhanced Color Doppler Ultrasonography for Preoperative Evaluation of Sentinel Lymph Node in Breast Cancer Patients

BACKGROUND

Sentinel lymph node (SLN) biopsy is the standard of care for breast cancer patients with non-palpable axillary lymph nodes. We evaluated the usefulness of contrast-enhanced ultrasonography in preoperative detection of malignant SLNs.

METHODS

50 patients with breast cancer (median age: 60 years) underwent a color power Doppler ultrasonography with intravenous contrast (Sonovue®) preoperatively, and findings suggestive of metastatic disease to the SLN were documented. The final histopathological report and the radiological preoperative record were compared. Finally, the sensitivity, specificity and diagnostic accuracy of this evolving diagnostic modality were calculated.

RESULTS

Contrast-enhanced ultrasound scan identified a negative SLN in the axilla of 27 patients and final histopathology was negative for 30 cases in total, so negative predictive value was calculated as 90% and positive predictive value was 75%. Overall sensitivity was 83.33% and specificity was 84.38%. Moreover, the ability of contrast-enhanced ultrasound to differentiate between SLN status was only statistically significantly correlated with the actual final histopathological report (p < 0.001), while successful ultrasound prediction was not correlated with any factor.

CONCLUSIONS

SLN status can be evaluated preoperatively using contrast-enhanced color Doppler ultrasonography with high accuracy.

Five cases of axillary lymph node metastatic breast cancer on contrast-enhanced sonography

This study was performed to determine the importance of contrast-enhanced sonography for axillary lymph node metastatic breast cancer. Contrast-enhanced sonographic findings in 5 patients with breast cancer and axillary lymph node metastasis are discussed, and imaging-pathologic correlations are also presented in 3 cases. In all 5 cases, lymph nodes showed a perfusion defect in the late phase. Rapid arterial enhancement and wash-out were observed in 2 cases in which we performed second injections. Contrast-enhanced sonography may be effective for identifying metastatic lesions in lymph nodes, especially in the early stages.

Growing indications for CEUS: The kidney, testis, lymph nodes, thyroid, prostate, and small bowel

Contrast enhanced ultrasonography (CEUS) is increasingly used for non-hepatic applications as well, so that nearly all organs have been investigated. Among them, there is a growing clinical use for a variety of pathologies of the kidney, testis, and small bowel. The possibility to differentiate benign from malignant nodes in cancer patients has been investigated. A new application is in the detection of sentinel nodes after intradermal microbubble injection. The need to distinguish thyroid nodules eligible for fine needle aspiration cytology has led to the use of CEUS in thyroid examinations as well. The potential of CEUS for prostate cancer detection has been extensively investigated, with encouraging initial results. Early promise, however, has not been fulfilled. New perspective regards evaluation of the extent of prostate tissue devascularization following ablative treatments.

Dynamic contrast-enhanced ultrasound for quantification of tissue perfusion

Dynamic contrast-enhanced ultrasound (US) imaging, a technique that uses microbubble contrast agents with diagnostic US, has recently been technically summarized and reviewed by a European Federation of Societies for Ultrasound in Medicine and Biology position paper. However, the practical applications of this imaging technique were not included. This article reviews and discusses the published literature on the clinical use of dynamic contrast-enhanced US. This review finds that dynamic contrast-enhanced US imaging is the most sensitive cross-sectional real-time method for measuring the perfusion of parenchymatous organs noninvasively. It can measure parenchymal perfusion and therefore can differentiate between benign and malignant tumors. The most important routine clinical role of dynamic contrast-enhanced US is the prediction of tumor responses to chemotherapy within a very short time, shorter than using Response Evaluation Criteria in Solid Tumors criteria. Other applications found include quantifying the hepatic transit time, diabetic kidneys, transplant grafts, and Crohn disease. In addition, the problems involved in using dynamic contrast-enhanced US are discussed.

Can contrast-enhanced ultrasound distinguish malignant from reactive lymph nodes in patients with head and neck cancers?

The purpose of this study was to investigate the utility of contrast-enhanced ultrasound in differentiating benign from malignant cervical lymph nodes in patients with squamous cell carcinoma of the head and neck. A consecutive series of 17 patients with known head and neck malignancy scheduled for neck surgery and lymph node clearance were recruited for contrast-enhanced ultrasound evaluation. Sonographic signal intensity as a function of time, comparing features of time to peak, time to arrival and time to wash-out, was quantified. The selected node was removed surgically and submitted for histology. Contrast-enhanced ultrasound examination had 100% sensitivity and 85.7% specificity for lymph node involvement. Functional analysis revealed contrast peaks significantly earlier in the malignant nodes (mean ± standard deviation) of 24.14 ± 2.7 s compared with 29.33 ± 3.4 s (p = 0.0128). Contrast-enhanced ultrasound holds promise in the detection and characterization of metastatic nodes that would not be diagnosed as abnormal on the basis of conventional ultrasound criteria.

[Ultrasound in the diagnostic management of malignant lymphomas]

Ultrasound is most useful in detecting and characterizing peripheral and abdominal lymph nodes and infiltration of solid organs. B-mode criteria, such as size, shape, number, distribution architecture, echogenicity and delineation of margins are the basis for characterizing lymph nodes. Additionally color coding techniques such as color Doppler, B-flow and contrast-enhanced ultrasound (CEUS) contribute to the evaluation of the nodal vasculature and vessel architecture. Whenever possible high frequency probes should not only be used for evaluating peripheral lymph nodes but also for lymphatic infiltration of solid organs, especially the spleen. The CEUS technique will be of additional benefit in detecting characterizing potential lymphatic organ infiltration. Ultrasound is an ideal tool for guided punctures, for which core biopsies should be preferred over fine needle aspiration biopsy and CEUS can also be used for proving residual viable tissue after chemotherapy or radiation therapy.