Neck lymph nodes: prediction by computer-assisted contrast medium analysis?

Contrast-enhanced ultrasound-based nomogram for predicting malignant involvements among sonographically indeterminate/suspicious cervical lymph nodes in patients with differentiated thyroid carcinoma

This prospective study was aimed at assessing the value of nomograms based on conventional and contrast-enhanced ultrasound (CEUS) features in the pre-operative diagnosis of sonographically indeterminate/suspicious lymph node metastasis (LNM) in patients with differentiated thyroid carcinoma (DTC). A total of 72 cervical LNs from 47 patients with DTC from January to June 2018 were included in the primary data set, and 30 LNs from 15 patients with DTC from July to August 2018 were included in the external validation data set. The LNs of the included patients were preoperatively evaluated by conventional ultrasound (US) and CEUS. Each included LN was labeled by puncture localization with carbon nanoparticle suspension injection (Canalin) under US guidance and dissected separately to ensure the one-to-one correspondence between ultrasonic features and pathology status. Univariate logistic regression analysis was used to identify risk factors for LNM. A nomogram was used to construct a prediction model for cervical metastatic LNs. Round shape, absence of hilar structure, peripheral or mixed blood flow and centripetal or mass enhancement were risk factors for lymph node metastases. The area under the receiver operating characteristic curve of the nomogram model based on conventional US and CEUS features was 0.93 (95% confidence interval: 0.872-0.985), which was superior to that of the nomogram based on conventional US features(0.85, 95% confidence interval: 0.707-0.989). CEUS features can provide incremental benefit in the diagnosis of LNM among DTC cohorts. Nomograms based on conventional US and CEUS features can predict LN status with high accuracy.

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.

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.

Evaluation of supplementary diagnostic value of contrast-enhanced ultrasound for lymph node puncture biopsy

Background

Contrast enhanced ultrasound (CEUS) is an effective way to evaluate the distribution of micro vessels in organs with little invasiveness. The qualitative evaluation and differential diagnosis of lymph node is essential for a number of clinical situations, including appropriate examination selection, oncologic staging, therapy and prognosis beyond diagnosis itself. The purpose of this study is to investigate the contribution of characterization of cervical lymphadenopathies on CEUS as an indication for lymph node puncture biopsy.

Methods

Records of 157 lymph nodes from 103 patients who had undergone CEUS examination were studied retrospectively, and enhancement patterns and characteristics were evaluated. The diagnoses obtained by means of core-needle biopsy examination or surgical removal, or patients were closely followed-up for at least 6 months. Of the lymph nodes examined, 94 were benign (48 lymphadenitis and 46 tuberculosis) and 63 were malignant (55 metastases and 8 lymphomas). The vascular characterization of lymph nodes was compared with results obtained by pathologic examination.

Results

The study using CEUS showed 55 (54.5%) cases of "peripheral" enhancement in group A and 47 (83.9%) cases of "hilar normal or activated" in group B. Inhomogeneous "spotted or cycle-like" enhancement in the equilibrium phase was seen in 80 (79.2%) cases of group A and only 11 (19.6%) cases of group B. The specificity, sensitivity and accuracy of CEUS examination result as an indication for puncture biopsy were 80.4%, 81.2% and 80.9%, respectively.

Conclusions

Centripetal perfusion in the early arterial phase or inhomogeneous spotted or cycle-like enhancement in the equilibrium phase of the cervical lymph nodes during CEUS can be used as an indication for core-needle biopsy with a high degree of accuracy. Conversely, for lymph nodes with more variable appearances, surgical removal or closely followed-up of nodes may be more appropriate.

Chapter 8 On the Horizon: Advanced Imaging Techniques to Improve Noninvasive Assessment of Cervical Lymph Nodes

Conventional imaging modalities are limited in the evaluation of lymph nodes as they predominantly rely on size and morphology, which have suboptimal sensitivity and specificity for malignancy. In this review we will explore the role of "on the horizon" advanced imaging modalities that can look beyond the size and morphologic features of a cervical lymph node and explore its molecular nature and can aid in personalizing therapy rather than use the "one-size-fits-all" approach.

Application of Computer-Aided Diagnosis to the Sonographic Evaluation of Cervical Lymph Nodes

We initiated an observer study to evaluate a computerized system developed in our previous study for automatic extraction of 10 features and estimation of the malignancy probability of cervical nodes in sonograms. In the present study, five expert radiologists and five resident radiologists interpreted the sonograms of 178 nodes. The malignancy rating and patient management recommendation (biopsy or follow-up) were made without and then with the computer aid. Under these two reading conditions, the performances of radiologists and agreement among a group of radiologists were evaluated by using the receiver operating characteristic (ROC) analysis and the κ statistic, respectively. With the computer aid, the performances of radiologists improved significantly, as indicated by the increase in the area under the ROC curve (Az) from 0.843 to 0.896 (p = 0.031) and from 0.705 to 0.822 (p < 0.001), for the expert and resident groups, respectively. Agreement among all 10 radiologists improved from slight to moderate as indicated by an increase in the κ value from 0.195 to 0.421 (p < 0.001). The average performance of residents with aid (Az = 0.822) was close to that of experts without aid (Az = 0.843). Results indicate that computer-aided diagnosis is useful to improve radiologist performance (especially that of inexperienced radiologists) in the ultrasonographic evaluation of cervical nodes and to reduce variability among radiologists.

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.

Review of ultrasonography of malignant neck nodes: greyscale, Doppler, contrast enhancement and elastography

Assessment of neck lymph nodes is essential in patients with head and neck cancers for predicting the patient’s prognosis and selecting the appropriate treatment. Ultrasonography is a useful imaging tool in the assessment of neck lymph nodes. Greyscale ultrasonography assesses the size, distribution, and internal architecture of lymph nodes. Doppler ultrasonography evaluates the intranodal vascular pattern and resistance of lymph nodes. Contrast-enhanced ultrasonography provides information on lymph node parenchymal perfusion. Elastography allows qualitative and quantitative assessment of lymph node stiffness. This article reviews the value of greyscale, Doppler and contrast-enhanced ultrasonography as well as elastography in the assessment of malignant nodes in the neck.

Results of treatment for pT1/pT2 carcinomas of the floor of mouth

CONCLUSION

In pT2 floor of mouth cancer (FOMC), a standardized neck dissection (ND) should be carried out, due to the high risk of occult metastases. In cases of pT1 carcinomas with a clinically negative neck using high imaging standards and expertise a tight 'wait and watch' strategy can be used.

OBJECTIVE

To report on the oncologic results with primary surgical treatment of pT1/pT2 FOMC and to examine the benefit of elective ND in cN0.

METHODS

This was a retrospective study design including 216 patients who were treated between 1980 and 2010 for pT1/2 FOMC. The 5-year disease-specific survival (DSS), local and (loco)regional control based on the T and N classification and depth of infiltration were investigated.

RESULTS

DSS was 79.5% and (loco)regional control was 89.8%. DSS in patients staged pN0 was significantly higher, at 84.6%, than in those staged pN+, at 60%. ND was performed in 165 patients, and adjuvant therapy was administered in 124 patients. Ninety patients (41.7%) were staged cN0, and 53.3% of them underwent elective ND. The risk of occult metastases was 4.8% in pT1 and 28.6% in pT2. A depth of infiltration of ≥ 5 mm showed a markedly higher relative frequency of occult neck metastases and pN+ status.

Enhanced sonographic imaging to diagnose lymph node metastasis: importance of blood vessel volume and density

Lymph node size is an important variable in ultrasound diagnosis of lymph node metastasis. However, the size criterion often leads to oversight of tumor-positive lymph nodes within the range of "normal" size, such that more accurate diagnostic criteria for lymph node metastasis are required. In this study, we show how diagnosis of lymph node metastasis can be improved by evaluating changes in blood vessel volume and density using a novel contrast-enhanced high-frequency ultrasound (CE-HFUS) system with Sonazoid. An MRL/MpJ-lpr/lpr (MRL/lpr) mouse model of lymph node metastasis was used in which lymph nodes are similar in size to humans. Metastasis via lymphatic vessels to proper axillary lymph nodes (proper ALN) was induced by injection of tumor cells into the subiliac lymph nodes. Within 21 days of injection, significant increases in blood vessel volume and density, but no increases in the size of the proper ALNs, were observed. The increase in blood vessel density was confirmed with immunohistochemical analysis and was positively related to tumor cell proliferation as measured using bioluminescence imaging. Together, our results showed that alterations in blood vessel volume and density precede alterations in lymph node size in the early stages of lymph node metastasis. Detection of these changes by ultrasonography may offer new criteria for early diagnosis of lymph node metastasis.

Preoperative cervical lymph node size evaluation in patients with malignant head/neck tumors: comparison between ultrasound and computer tomography

PURPOSE

The spread of malignant lymph nodes due to malignancies of the head and neck is systematically observed. However, sentinel lymph nodes in the cervical region, such as in the axillary or supraclavicular regions, are not described. Therefore, precise preoperative lymph node screening of all neck compartments is required.

MATERIALS AND METHODS

Forty-five patients with a primary malignant tumor in the head and neck area underwent lymph node staging of the head by means of both CT and ultrasound as a preoperative evaluation. The lymph nodes were classified on the origin of the level system proposed by Som et al. (174:837-844, 2000), which is based on the recommendation of the American College of Radiology introduced in 1990. According to the manual measurement of World Health Organization and the Revised Response Evaluation Criteria in Solid Tumors, the longest transversal and longitudinal diameters were measured by ultrasound, while only the two longest transversal diameters were recorded by CT. The study was conducted by two independent observers. These results were compared with the histopathological results as references.

RESULTS

Six hundred and twenty-four lymph nodes were detected, 64 of which were malignant. Most of the transformed lymph nodes were found in level IIa, II b and III. A more precise measurement was given using ultrasound. The correct positive rate of sonographically detected malignant lymph nodes was significantly higher compared to the CT reading.

CONCLUSION

Cervical lymph node staging can be performed safely by ultrasound. It is a cheap, easy-to-handle and cost-effective diagnostic method. However, only the uppermost regions of the neck are accessible with a linear transducer. Despite this restriction, ultrasound is a reliable and valuable tool for screening lymph nodes in the case of a head or neck malignancy.

Ultrasonographic feature selection and pattern classification for cervical lymph nodes using support vector machines

A rough margin based support vector machine (RMSVM) classifier was proposed to improve the accuracy of ultrasound diagnoses for cervical lymph nodes. Thirty-six features belonging to 10 kinds of ultrasonographic characteristics were extracted for each of 110 lymph nodes in ultrasonograms. Comparison studies were done for three classifiers--the classical support vector machine (SVM), the general regression neural network and the proposed RMSVM, with or without the feature selection by the recursive feature elimination (RFE) algorithm, respectively, based on SVMs and the mean square error discriminant. It was indicated by experimental results that all classifiers benefited from the feature selection. The best classification performance was obtained by the RMSVM using thirteen features selected by the RMSVM based RFE, which yielded the normalized area under the receiver operating characteristic curve (A(z)) of 0.859. Compared with the radiologist's performance of A(z) of 0.787, the developed computer-aided diagnosis algorithm has the potential to improve the diagnostic accuracy.