Node Imaging Research Articles

Should patients with early mycosis fungoides, a skin cancer of immune cells, undergo imaging to detect lymph node involvement?

Mycosis fungoides (MF) is a form of lymphoma, a cancer of immune cells called lymphocytes. In the early stages of MF only the skin is involved in the form of patches or plaques. In the later stages the skin is characterized by the appearance of nodules or generalized skin involvement, and the lymphoma may spread beyond the skin to involve primarily lymph nodes (glands) that become enlarged. In order to accurately assess the size and the structure of the lymph nodes imaging is needed. Because of the rarity of involvement of lymph nodes in patients with MF who have patches or plaques, current guidelines differ about the need to perform imaging at this early stage. In daily practice, there are physicians who recommend imaging in patch‐plaque MF only in the presence of enlarged lymph nodes on clinical examination. Policies vary between countries and between centres.

Fluorescent Ag–In–S/ZnS Quantum Dots for Tumor Drainage Lymph Node Imaging In Vivo

Tumor drainage lymph node imaging is crucial for oncological surgery, where the complete dissection of sentinel lymph nodes could largely prevent/delay recurrence. However, current commercially use...

Multi-factorial considerations for intra-thoracic lymph node evaluations of healthy cats on computed tomographic images

BackgroundIt is difficult to examine mild to moderate feline intra-thoracic lymphadenopathy via and thoracic radiography. Despite previous information from computed tomographic (CT) images of intra-thoracic lymph nodes, some factors from animals and CT setting were less elucidated. Therefore, this study aimed to investigate the effect of internal factors from animals and external factors from the CT procedure on the feasibility to detect the intra-thoracic lymph nodes. Twenty-four, client-owned, clinically healthy cats were categorized into three groups according to age. They underwent pre- and post-contrast enhanced CT for whole thorax followed by inter-group evaluation and comparison of sternal, cranial mediastinal, and tracheobronchial lymph nodes.ResultsPost contrast-enhanced CT appearances revealed that intra-thoracic lymph nodes of kittens were invisible, whereas the sternal, cranial mediastinal, and tracheobronchial nodes of cats aged over 7 months old were detected (6/24, 9/24 and 7/24, respectively). Maximum width of these lymph nodes were 3.93 ± 0.74 mm, 4.02 ± 0.65 mm, and 3.51 ± 0.62 mm, respectively. By age, lymph node sizes of these cats were not significantly different. Transverse lymph node width of males was larger than that of females (P = 0.0425). Besides, the detection score of lymph nodes was affected by slice thickness (P < 0.01) and lymph node width (P = 0.0049). Furthermore, an irregular, soft tissue structure, possibly the thymus, was detected in all juvenile cats and three mature cats.ConclusionsDespite additional information on intra-thoracic lymph nodes in CT images, which can be used to investigate lymphatic-related abnormalities, age, sex, and slice thickness of CT images must be also considered.

Deep learning system for lymph node quantification and metastatic cancer identification from whole-slide pathology images.

Traditional diagnosis methods for lymph node metastases are labor-intensive and time-consuming. As a result, diagnostic systems based on deep learning (DL) algorithms have become a hot topic. However, current research lacks testing with sufficient data to verify performance. The aim of this study was to develop and test a deep learning system capable of identifying lymph node metastases. 921 whole-slide images of lymph nodes were divided into two cohorts: training and testing. For lymph node quantification, we combined Faster RCNN and DeepLab as a cascade DL algorithm to detect regions of interest. For metastatic cancer identification,we fused Xception and DenseNet-121 models and extracted features. Prospective testing to verify the performance of the diagnostic system was performed using 327 unlabeled images. We further validated the proposed system using Positive Predictive Value (PPV) and Negative Predictive Value (NPV) criteria. We developed a DL-based system capable of automated quantification and identification of metastatic lymph nodes. The accuracy of lymph node quantificationwas shown to be 97.13%. The PPV of the combined Xception and DenseNet-121 model was 93.53%, and the NPV was 97.99%. Our experimental results show that the differentiation level of metastatic cancer affects the recognition performance. The diagnostic system we established reached a high level of efficiency and accuracy of lymph node diagnosis. This system could potentially be implemented into clinical workflow to assist pathologists in making a preliminary screening for lymph node metastases in gastric cancer patients.

Merkel cell carcinoma.

Merkel cell carcinoma (MCC) of the skin is a rare, aggressive form of skin cancer that metastasizes to other parts of the body. This cutaneous neuroendocrine tumour mainly affects older people, with most cases generally occurring over the age of 50years. Merkel cell polyomavirus has been shown to induce gene mutations resulting in this skin cancer, with immunosuppression and ultraviolet radiation being other key risk factors in its pathogenesis. MCC is clinically seen as a rapidly enlarging, isolated, irregular erythematous nodule typically found on sun-exposed sites. Diagnosis is through clinical examination followed by tissue biopsy, which demonstrates characteristic histopathological neuroendocrine features. Immunohistochemistry plays a crucial role in diagnosis with the characteristic perinuclear staining with cytokeratin-20 helping to differentiate it from other morphologically similar tumours. Sentinel lymph node biopsy and imaging is essential for staging and determining prognosis. Surgical excision is the mainstay of treatment for localized disease although adjuvant radiotherapy is often required. Metastatic disease involves a very poor prognosis, and immune checkpoint inhibitors have recently shown promise in the treatment of metastatic disease. Avelumab, a monoclonal antibody that binds to the programmed death-1 receptor, has been approved by the National Institute for Health and Care Excellence and shown encouraging survival outcomes. It provides an option for treating metastatic carcinoma in adults after they have failed ≥1 line of chemotherapy for metastatic disease.

Innovative Radiopharmaceuticals for Cancer Diagnosis and Treatment

The presented material summarizes the experience of Cancer Research Institute and Tomsk Polytechnical University team in the development of original radiopharmaceuticals (RP) for nuclear medicine. The first such unique for world nuclear medicine RP was a Thallium­199. The Thallium­199 is successfully used for breast cancer diagnosis and its lymphogenous metastasis, as well as to visualize cancer of the larynx and laryngopharynx, their relapses and for differential diagnosis of inflammatory and tumor processes of the musculoskeletal system. The great practical importance for nuclear medicine has the organization of a waste­free production of sorption and extraction generators of Technetium­-99m at the IRT­T TPU nuclear research reactor, as well as the creation of a fully automated 99mTc module operating on a waste­ free technology. The development of the 99mTc­Alotech for targeting imaging of sentinel lymph nodes (SLN) has also great importance for clinical oncology. The main advantage of 99mTc­Glucoscin is that metabolic tumor imaging with the innovative RP use can be performed using a conventional gamma camera, which significantly reduces the cost of the diagnostic procedure. The present and promising developments of the research teams of the Tomsk Scientific Research Center and the Tomsk Polytechnic University are closely related to theranostics — the use of RPs obtained on the basis of same target compound labeled with different isotopes intended for the diagnosis or therapy of oncological diseases.

Accuracy of Radiological Axillary Staging for Breast Cancer Patients with Neoadjuvant Chemotherapy

Purpose Neoadjuvant chemotherapy (NACT) in breast cancer patients has the advantage of decreasing related morbidities by reducing the extent of axillary surgery. However, it remains a controversy with regards to the appropriate extent of axillary lymph node dissection after NACT. Therefore, this study aims to investigate the accuracy of breast ultrasonography (US) and breast magnetic resonance imaging (MRI) to assess the axillary nodal status after NACT. Methods We reviewed pre- and post-NACT axillary imaging and clinicopathological data of patients who received NACT for primary breast cancer and underwent surgery. After NACT, accuracy of imaging modalities were evaluated through the comparison of pathologic lymph node (LN) status and imaging LN status. Results Fifty seven patients completed NACT and underwent surgery. Breast US was found to have a sensitivity of 61.1%, specificity of 57.7%, negative predictive value (NPV) of 68.2%, and positive predictive value (PPV) of 50.0%. For breast MRI, sensitivity was 58.3%, specificity 75.8%, NPV 71.4%, and PPV 63.6%. For US combined with MRI, sensitivity was 66.7%, specificity 54.5%, NPV 69.2%, and PPV 51.6%. The accuracy of imaging modalities was 59.1% for US, 68.4% for MRI, and 59.6% for US combined with MRI. Conclusion In breast cancer patients who received NACT, MRI showed a higher specificity, NPV, and PPV than US, although it had a lower sensitivity. However, due to the low accuracy, breast MRI alone is not sufficient to determine the extent of axillary surgery. Therefore, determining the extent of axillary surgery based on the results of intraoperative sentinel lymph node biopsy may be the right method for accurate staging. Keywords: Breast neoplasms; Magnetic resonance imaging; Neoadjuvant therapy; Ultrasonography

Deep learning for in vivo near-infrared imaging

Detecting fluorescence in the second near-infrared window (NIR-II) up to ∼1,700 nm has emerged as a novel in vivo imaging modality with high spatial and temporal resolution through millimeter tissue depths. Imaging in the NIR-IIb window (1,500-1,700 nm) is the most effective one-photon approach to suppressing light scattering and maximizing imaging penetration depth, but relies on nanoparticle probes such as PbS/CdS containing toxic elements. On the other hand, imaging the NIR-I (700-1,000 nm) or NIR-IIa window (1,000-1,300 nm) can be done using biocompatible small-molecule fluorescent probes including US Food and Drug Administration-approved dyes such as indocyanine green (ICG), but has a caveat of suboptimal imaging quality due to light scattering. It is highly desired to achieve the performance of NIR-IIb imaging using molecular probes approved for human use. Here, we trained artificial neural networks to transform a fluorescence image in the shorter-wavelength NIR window of 900-1,300 nm (NIR-I/IIa) to an image resembling an NIR-IIb image. With deep-learning translation, in vivo lymph node imaging with ICG achieved an unprecedented signal-to-background ratio of >100. Using preclinical fluorophores such as IRDye-800, translation of ∼900-nm NIR molecular imaging of PD-L1 or EGFR greatly enhanced tumor-to-normal tissue ratio up to ∼20 from ∼5 and improved tumor margin localization. Further, deep learning greatly improved in vivo noninvasive NIR-II light-sheet microscopy (LSM) in resolution and signal/background. NIR imaging equipped with deep learning could facilitate basic biomedical research and empower clinical diagnostics and imaging-guided surgery in the clinic.

Detection of follicular regions in actin-stained whole slide images of the human lymph node byshock filter.

Human lymph nodes play a central part of immune defense against infection agents and tumor cells. Lymphoid follicles are compartments of the lymph node which are spherical, mainly filled with Bcells. Bcells are cellular components of the adaptive immune systems. In the course of a specific immune response, lymphoid follicles pass different morphological differentiation stages. The morphology and the spatial distribution of lymphoid follicles can be sometimes associated to a particular causative agent and development stage of a disease. We report our new approach for the automatic detection of follicular regions in histological whole slide images of tissue sections immuno-stained with actin. The method is divided in two phases: (1) shock filter-based detection of transition points and (2) segmentation of follicular regions. Follicular regions in 10 whole slide images were manually annotated by visual inspection, and sample surveys were conducted by an expert pathologist. The results of our method were validated by comparing with the manual annotation. On average, we could achieve a Zijbendos similarity index of 0.71, with a standard deviation of 0.07.

Characterization of an angular domain fluorescence optical projection tomography system for mesoscopic lymph node imaging.

Transmittance and fluorescence optical projection tomography can offer high-resolution and high-contrast visualization of whole biological specimens; however, applications are limited to samples exhibiting minimal light scattering. Our previous work demonstrated that angular-domain techniques permitted imaging of ∼1cm diameter noncleared lymph nodes because of their low scattering nature. Here, an angle-restricted transmittance/fluorescence system is presented and characterized in terms of geometric and fluorescence concentration reconstruction accuracy as well as spatial resolution, depth of focus, and fluorescence limits of detection. Using lymph node mimicking phantoms, results demonstrated promising detection and localization capabilities relevant for clinical lymph node applications.

Clinical applications of receptor-binding radiopharmaceutical 99mTc-Tilmanocept: sentinel node biopsy and beyond

99mTc-tilmanocept is the first mannose-containing, receptor-directed, radiopharmaceutical for molecular imaging and mapping of sentinel lymph nodes (SLNs) in solid tumor staging. This review focuses on the approved and innovative clinical application of 99mTc-tilmanocept. 99mTc-Tilmanocept is a new-generation radiotracer designed to overcome certain limitations of the conventionally used radiocolloids. The superior efficacy profile of 99mTc-tilmanocept has been demonstrated in several preclinical and clinical studies based on its specific properties like rapid injection site clearance, high uptake in the first node, and low distal node accumulation. The capability of 99mTc-tilmanocept for selective molecular imaging of the CD206 receptor may be used for diagnosis and treatment of several macrophage mediated diseases, including autoimmune diseases, infectious diseases (HIV and tuberculosis), neurodegenerative disorders (dementias) and cardiovascular disease (vulnerable plaque and atherosclerosis).

Room-Temperature Phosphorescence Resonance Energy Transfer for Construction of Near-Infrared Afterglow Imaging Agents.

Afterglow imaging that detects photons after cessation of optical excitation avoids tissue autofluorescence and thus possesses higher sensitivity than traditional fluorescence imaging. Purely organic molecules with room-temperature phosphorescence (RTP) have emerged as a new library of benign afterglow agents. However, most RTP luminogens only emit visible light with shallow tissue penetration, constraining their in vivo applications. This study presents an organic RTP nanoprobe (mTPA-N) with emission in the NIR range for in vivo afterglow imaging. Such a probe is composed of RTP molecule (mTPA) as the phosphorescent generator and an NIR-fluorescent dye as the energy acceptor to enable room-temperature phosphorescence resonance energy transfer (RT-PRET), ultimately resulting in redshifted phosphorescent emission at 780nm. Because of the elimination of background noise and redshifted afterglow luminescence in a biologically transparent window, mTPA-N permits imaging of lymph nodes in living mice with a high signal-to-noise ratio. This study thus opens up a universal approach to develop organic RTP luminogens into NIR afterglow imaging agents via construction of RT-PRET.

The Role of Magnetic Resonance Imaging in (Future) Cancer Staging: Note the Nodes.

The presence or absence of lymph node metastases is a very important prognostic factor in patients with solid tumors. Current invasive and noninvasive diagnostic methods for N-staging like lymph node dissection, morphologic computed tomography/magnetic resonance imaging (MRI), or positron emission tomography-computed tomography have significant limitations because of technical, biological, or anatomical reasons. Therefore, there is a great clinical need for more precise, reliable, and noninvasive N-staging in patients with solid tumors. Using ultrasmall superparamagnetic particles of ironoxide (USPIO)-enhanced MRI offers noninvasive diagnostic possibilities for N-staging of different types of cancer, including the 4 examples given in this work (head and neck cancer, esophageal cancer, rectal cancer, and prostate cancer). The excellent soft tissue contrast of MRI and an USPIO-based differentiation of metastatic versus nonmetastatic lymph nodes can enable more precise therapy and, therefore, fewer side effects, essentially in cancer patients in oligometastatic disease stage. By discussing 3 important questions in this article, we explain why lymph node staging is so important, why the timing for more accurate N-staging is right, and how it can be done with MRI. We illustrate this with the newest developments in magnetic resonance methodology enabling the use of USPIO-enhanced MRI at ultrahigh magnetic field strength and in moving parts of the body like upper abdomen or mediastinum. For prostate cancer, a comparison with radionuclide tracers connected to prostate specific membrane antigen is made. Under consideration also is the use of MRI for improvement of ex vivo cancer diagnostics. Further scientific and clinical development is needed to assess the accuracy of USPIO-enhanced MRI of detecting small metastatic deposits for different cancer types in different anatomical locations and to broaden the indications for the use of (USPIO-enhanced) MRI in lymph node imaging in clinical practice.

Lymph Node Subcapsular Sinus Microenvironment-On-A-ChipModeling Shear Flow Relevant to Lymphatic Metastasis and Immune Cell Homing.

SummaryA lymph node sinus-on-a-chip adhesion microfluidic platform that recapitulates the hydrodynamic microenvironment of the lymph node subcapsular sinus was engineered. This device was used to interrogate the effects of lymph node remodeling on cellular adhesion in fluid flow relevant to lymphatic metastasis. Wall shear stress levels analytically estimated and modeled after quiescent and diseased/inflamed lymph nodes were experimentally recapitulated using a flow-based microfluidic perfusion system to assess the effects of physiological flow fields on human metastatic cancer cell adhesion. Results suggest that both altered fluid flow profiles and presentation of adhesive ligands, which are predicted to manifest within the lymph node subcapsular sinus as a result of inflammation-induced remodeling, and the presence of lymph-borne monocytic cells may synergistically contribute to the dynamic extent of cell adhesion in flow relevant to lymph node invasion by cancer and monocytic immune cells during lymphatic metastasis.

Modified polymer dots for multi-scale multi-modal imaging of lymphatic system in tumor pre-metastasis

Lymphatic system plays a vital role in facilitating tumor metastasis in the early stage. It is urgent to understand the structure, development and function of the lymphatics via the high-resolution and real-time imaging during the period. In this study, by using different ratios of polymer dots (Pdots) as nanoprobe, multi-scale multi-modal imaging methods are employed to observe the structure and function of the lymphatics in the tumor-bearing mice. Our findings demonstrate that the lymphatics display enlargement and thickening before the tumor metastasis. Moreover, the distortions, burrs, new-born branches and dysfunctional valves are observed. Furthermore, the combination of multiphoton confocal microscope and uDICSO realizes the complete transparency and super-resolution imaging of lymph nodes and lymphatic vessels together for the first time. These results show the exciting possibility of using functional Pdots for imaging the lymphatics in tumor metastasis, development and disease models in small animals.

New Developments in Imaging for Sentinel Lymph Node Biopsy in Early-Stage Oral Cavity Squamous Cell Carcinoma.

Simple SummaryIn early-stage (cT1-2N0) oral cancer, occult lymph node metastases are present in 20–30% of patients. Accordingly, accurate staging of the clinically negative cervical nodal basin is warranted in these patients. Sentinel lymph node biopsy has proven to reliably stage the clinically negative cervical nodal basin in early-stage oral cancer. However, due to the limited resolution of conventional sentinel lymph node imaging, occult lymph node metastasis may be missed in particular circumstances. Therefore, technical developments are necessary to bring the diagnostic accuracy of sentinel lymph node biopsy, in early-stage oral cancer, to a higher level. This review evaluates novel sentinel lymph node imaging techniques for early-stage oral cancer, such as MR lymphography, CT lymphography, PET lymphoscintigraphy and contrast-enhanced lymphosonography. Their reported diagnostic accuracy is described and their relative merits, disadvantages and potential applications are outlined.Sentinel lymph node biopsy (SLNB) is a diagnostic staging procedure that aims to identify the first draining lymph node(s) from the primary tumor, the sentinel lymph nodes (SLN), as their histopathological status reflects the histopathological status of the rest of the nodal basin. The routine SLNB procedure consists of peritumoral injections with a technetium-99m [99mTc]-labelled radiotracer followed by lymphoscintigraphy and SPECT-CT imaging. Based on these imaging results, the identified SLNs are marked for surgical extirpation and are subjected to histopathological assessment. The routine SLNB procedure has proven to reliably stage the clinically negative neck in early-stage oral squamous cell carcinoma (OSCC). However, an infamous limitation arises in situations where SLNs are located in close vicinity of the tracer injection site. In these cases, the hotspot of the injection site can hide adjacent SLNs and hamper the discrimination between tracer injection site and SLNs (shine-through phenomenon). Therefore, technical developments are needed to bring the diagnostic accuracy of SLNB for early-stage OSCC to a higher level. This review evaluates novel SLNB imaging techniques for early-stage OSCC: MR lymphography, CT lymphography, PET lymphoscintigraphy and contrast-enhanced lymphosonography. Furthermore, their reported diagnostic accuracy is described and their relative merits, disadvantages and potential applications are outlined.

Feasibility of prognosis assessment for cancer of unknown primary origin using texture analysis of 18F-fluorodeoxyglucose PET/computed tomography images of largest metastatic lymph node.

Cancers of unknown primary origin cannot be staged using images, making the prognosis difficult. We attempted to predict prognosis of patients with unknown primary origin using tumour heterogeneity recently introduced in F-fluorodeoxyglucose (F-FDG) PET/computed tomography (CT). Overall, 30 patients with unknown primary origin who underwent whole-body F-FDG PET/CT scans were retrospectively enrolled for texture analysis. The volume of interest was placed in the largest metastatic lymph nodes and conventional parameters and grey-level co-occurrence matrix (GLCM) were calculated. Statistical analysis of image-based variables was performed using Cox regression analyses. Patients were stratified into two groups based on cutoff values of GLCMentropy obtained using receiver operating characteristics (ROCs). Patients were analyzed, and overall survival (OS) was compared using Kaplan-Meier analysis. Univariate Cox regression analysis showed significant differences in prognosis for parenchymal organ metastasis (P < 0.01), GLCM homogeneity (P = 0.01), GLCMcontrast (P < 0.01), GLCMentropy (P < 0.01) and GLCMdissimilarity (P < 0.01). Multivariate Cox regression analysis showed a significant difference in reduced prognosis for GLCMentropy positive (P < 0.01). Stratification was performed based on the GLCMentropy cutoff value, determined using ROCs analysis, with smaller groups showing better OS. Despite previous difficulties in predicting prognosis in patients with unknown primary origin, F-FDG PET/CT texture features may enable stratification of prognosis. This could be useful for appropriate patient selection and management and help identify a subset of patients with favourable outcomes. These novel findings may be helpful for prognostication and improving patient care.

Predictive value of sentinel lymph node imaging and biopsy in early cervical cancers: correlation with scintigraphic uptake patterns and histology.

This study was designed to 1) assess the feasibility, standardization of sentinel lymph node imaging (SLNI) and biopsy in early cervical cancers and also to determine the detection rates. 2) To analyze the SLN uptake pattern and correlate the findings with the histological grades of tumor. 52 early cervical cancer patients underwent same-day Tc sulfur colloid (filtered) SLNI and biopsy with gamma probing. Patients underwent radical hysterectomy, para-aortic and pelvic lymphadenectomy irrespective of sentinel lymph node biopsy (SLNB) findings. We analyzed the colloid transit times, uptake pattern, lymphatic groups involved and histology. A total of 203 hot nodes (100% detection rate) were detected and harvested. Study showed 100% sensitivity, specificity, and negative predictive value. Internal iliac nodes were predominantly involved. Lymphatic uptake patterns were graded and correlated with tumor histology (Ki index). Transit time was relatively prolonged in patients with aggressive tumors. SLNI and biopsy in early cervical malignancies are feasible with high detection rate. Scintigraphic patterns of nodal uptake were relevant and found to correlate with the tumor histological grades. We found that nonfocal nodal uptake patterns were mainly encountered in patients with tumors having higher Ki index. Immunohistochemistry further facilitated identification of lymph nodal metastases. The visual grading system, implemented in this study provides a good indication of the degree of impairment of lymphatic drainage. Higher visual scintigraphic grade denotes greater lymphatic tumor burden.

Lack of distinct molecular profile of Primary Dermal Melanoma

Primary dermal melanoma (PDM) is a rare variant of melanoma which simulates metastatic melanoma to the skin. Diagnosis of PDM cannot be established on histologic grounds alonebut requires absence of evidence of melanoma elsewhere by clinical history and/or imaging studies. Despite this entity being clinically well documented, limited data on molecular characterization are available. We performed comprehensive mutation and copy number variation analysis in a series of PDMs in search for distinctive molecular features.Studies were approved by respective institutional review boards. Six cases fulfilling strict histologic criteria of PDM were identified in patients with absent history of melanoma elsewhere, negative sentinel lymph node biopsies and imaging studies. DNA was extracted from formalin-fixed, paraffin-embedded (FFPE) tissue, and five cases passed quality control measures and were subjected to targeted exon sequencing using the Memorial Sloan Kettering-Integrated Mutation Profiling of Actionable Cancer Targets 410 panel. Two of five PDM carried NRAS hotspot mutations characteristic of cutaneous melanoma (CM) genomic subtypes. One case showed a probable low-activating NRAS mutation in combination with additional aberrations in other mitogen-activated protein kinase (MAPK) pathway effectors. Hotspot mutations were also identified in the TERT promoter region, and one tumor showed a mutation in the SWI/SNF remodeling complex. No oncogenic mutations were identified in one case. Furthermore, none of the tumors analyzed showed activating mutations in Gα subunits, including GNAQ and GNA11. Copy number alterations included deletions of Chr 9p, characteristic of CM.Despite PDM showing mutational heterogeneity, our findings suggest predominance of MAPK pathway aberrations in agreement with the mutational profile of CMs in general. Given the absence of genetic overlap with other distinct primary dermal melanocytic proliferations, mutational profiling will unlikely aid in the difficult differential diagnosis of PDM versus melanoma metastasis. Thorough metastatic workup remains crucial in establishing this rare diagnosis.

Diagnostic accuracy of ultrasound superb microvascular imaging for lymph nodes: A protocol for systematic review and meta-analysis.

Background:As a novel ultrasound technique, superb microvascular imaging can quickly, simply and noninvasively study the microvascular distribution in the tumor and evaluate the microvascular perfusion. Studies suggested that superb microvascular imaging is helpful for the differentiation between benign and malignant lymph nodes. However, the results of these studies have been contradictory. Therefore, the present meta-analysis aimed at determining the accuracy of superb microvascular imaging in the differential diagnosis between benign and malignant lymph nodes.Methods:We will search PubMed, Web of Science, Cochrane Library, and Chinese biomedical databases from their inceptions to the July 30, 2020, without language restrictions. Two authors will independently carry out searching literature records, scanning titles and abstracts, full texts, collecting data, and assessing risk of bias. Review Manager 5.2 and Stata14.0 software will be used for data analysis.Results:This systematic review will determine the accuracy of superb microvascular imaging in the differential diagnosis between benign and malignant lymph nodes.Conclusion:Its findings will provide helpful evidence for the accuracy of superb microvascular imaging in the differential diagnosis between benign and malignant lymph nodes.Systematic review registration:INPLASY202070133.