Imaging of lymph nodes in the neck

Whole-body [18F]-FDG-PET/MRI for staging of pediatric non-Hodgkin lymphoma: first results from a single-center evaluation

Aim

In 2015, the revised International Pediatric Non-Hodgkin Lymphoma Staging System was published. It mentions [¹⁸F]-FDG-PET/MRI as the latest method to perform whole-body imaging. However, supporting data are pending. Our aim was to investigate the performance of whole-body [¹⁸F]-FDG-PET/MRI in pediatric non-Hodgkin lymphoma patients by using a limited number of MRI sequences.

Materials and methods

Ten pediatric patients with histologically proven non-Hodgkin lymphoma underwent whole-body [¹⁸F]-FDG-PET/MRI at staging. The retrospective analysis included three steps: First, [¹⁸F]-FDG-PET and MR scans were evaluated separately by a nuclear medicine physician and a pediatric radiologist. Nineteen nodal and two extranodal regions as well as six organs were checked for involvement. Second, discrepant findings were reviewed together in order to reach consensus. Third, [¹⁸F]-FDG-PET/MRI findings were correlated with the results of other clinical investigations.

Results

Of the 190 lymph node regions evaluated, four were rated controversial. Consensus was reached by considering metabolic, functional and morphologic information combined. Concordantly, [¹⁸F]-FDG-PET and MRI detected Waldeyer’s ring involvement in two patients whose Waldeyer’s ring was negative on clinical assessment. In four patients MRI showed pleural effusion. However, in only two of them an increased glucose metabolism as a reliable sign of pleural involvement was detectable. In six patients [¹⁸F]-FDG-PET and MRI detected skeletal lesions although bone marrow biopsy was positive in only one of them.

Conclusion

Despite the small number of cases evaluated, whole-body [¹⁸F]-FDG-PET turned out to be a valuable tool for staging of pediatric non-Hodgkin lymphoma.

Parotid Lymphadenopathy Is Associated With Joint Effusion in Non-Neoplastic Temporomandibular Disorders

PURPOSE

Lymphadenopathy often occurs in the setting of inflammation, with or without infection. We sought to elucidate any association of parotid lymphadenopathy with joint effusion in temporomandibular joint (TMJ) disorders.

MATERIALS AND METHODS

We performed a retrospective cohort study. We analyzed the magnetic resonance imaging studies of patients with suspected TMJ disorders performed from April 2006 to March 2007. The degree of joint effusion was graded on sagittal T₂-weighted spin echo images according to a commonly used system. On axial short T₁-weighted short inversion recovery images, the number and short-axis diameter of the parotid lymph nodes were recorded. We performed analyses of the cluster-correlated data using the Mann-Whitney U test and Spearman's correlation coefficients. P < .05 was considered to indicate significance. To assess the possible predictive value of certain variables, a generalized linear model (generalized estimation equation) was constructed, considering the multiple measurements.

RESULTS

A total of 402 TMJ disorders were analyzed from 201 patients during the study period. The number and size of the parotid lymph nodes identified was significantly greater in the patients with TMJ effusion (P < .01) than in those without effusion.

CONCLUSION

In the present study, we found an association between parotid lymphadenopathy and joint effusion in TMJ disorders. These findings indicate that lymphadenopathy should be considered as an inflammation condition commonly associated with joint effusion in TMJ disorders.

Labeling of cervical lymph node levels during neck dissection: from ex vivo to in situ mapping

OBJECTIVES

To analyze the error rate of ex vivo mapping and to evaluate in situ mapping of lymph node (LN) levels during neck dissection (ND) METHODS: We retrospectively reviewed the pathological data on metastatic LN levels in head and neck cancer patients that had ND and ex vivo mapping of LN levels. Among them, we included the data from 43 patients that had a high risk for metastatic nodes based on both the preoperative CT and PET/CT. We compared the metastatic node levels based on the radiological studies and surgical pathology. In addition, we prospectively evaluated the accuracy of in situ mapping (N = 20).

RESULTS

With ex vivo mapping, the discrepancy between the radiological results and the pathological reports was 11.6% (5 out of 43); two side mismatches, two up down mismatches, and one faulty labeling, and in 7.0% (3 out of 43), the adjuvant treatment was redirected. However, in situ mapping of LN levels during ND resulted in no differences between the post-operative pathological and preoperative radiological findings.

CONCLUSION

Ex vivo mapping of LN levels had an error rate of 11.6% in labeling of LN levels. In situ mapping of cervical LN levels during ND provided more accurate results about the status of LN metastasis.

Magnetic resonance imaging of oropharyngeal cancer

Magnetic resonance imaging (MRI) is a powerful tool for cross-sectional analysis of head and neck anatomy and pathology. This is especially true with regard to oropharyngeal neoplasms, where soft tissue spread, nodal disease, perineural extension, and osseous involvement may significantly alter therapy and prognosis. In this article, we will provide a background on oropharyngeal cancers and MRI techniques and strategies, describing potential advantages of MRI with regard to particular anatomic subsites of the oropharynx. Future imaging trends in perfusion and diffusion MRI of such cancers are also discussed.

Lymph node staging

Cancers of the head and neck (HNC) include cancers of the larynx, nasal passages/nose, oral cavity, pharynx, salivary glands, buccal regions, and thyroid. In these cancers, lymph node staging and localization of pathological lymph nodes are necessary to decide on either (neo) adjuvant or surgical therapy and are a major factor for the prognosis in HNC patients. Cervical node metastases have different incidence, and their presence is associated with a decrease in global survival to roughly half and with higher recurrence rates. The node metastases can be categorized in the following 2 groups: overt (clinical) or nonovert (occult). The latter can be subcategorized as metastases detectable by traditional methods (eg, staining) or "submicroscopic" metastases, only evident with immunohistochemical or molecular analysis. Compared with clinical invasive and laboratory examinations, which may have complications and are expensive, radiology plays an important role in lymph node staging. Mainly, the overt node metastases are the field of radiological imaging, and second, the detection of nonovert metastases is important and holds promise for the future because many patients of those initially classified as cN0 have, in fact, occult metastatic disease (pN1). Vice versa, radiological imaging has to avoid false-positive results that can lead to an elective or radical neck dissection, which are associated with increased morbidity and mortality and thus overshadow the improvement in survival. Radiological imaging plays a role not only as an initial staging of N+ but also in the case of N0 due to the continuing controversy for the treatment of N0 patients. A close observation of the patient may reveal a positive node in the follow-up. The imaging modalities used for the node staging in HNC patients include ultrasound, contrast-enhanced computed tomography, contrast-enhanced magnetic resonance imaging (MRI), and positron emission tomography scans. None of the above-mentioned methods reaches a 100% sensitivity or specificity, and the accuracy of the exact number of metastases or levels involved has not been studied; thus, neck dissection with subsequent pathological examination remains the gold standard for node staging. Among the described cross-sectional imaging modalities, MRI presents a lot of advantages mainly due to the increased soft tissue contrast and the ability to obtain tissue characteristics in different sequences, including diffusion- and perfusion-weighted sequences and proton spectroscopy imaging. The lack of the radiation burden makes MRI suitable for a close follow-up of the patient, and the imaging with the use of new intravenous contrast material (such as ultrasmall iron oxide particles) seems superior to the conventional. In this article, we will focus on the lymph node MRI staging in HNC patients and the MR anatomy of the nodes, the necessary diagnostic workup, and the advantages of the method over computed tomography. The possibilities of the new imaging sequences and the treatment implications will be addressed as well.

Modern imaging lymph node staging of the head and neck region

The aim of this paper is to describe the modern imaging methods, their techniques, ability, and performance in staging head and neck lymph nodes. Also, the imaging morphologies of benign and malignant lymph nodes according to the different imaging techniques will be delineated. The imaging techniques of ultrasound including contrast-enhanced ultrasound, computed tomography and magnetic resonance imaging (MRI) including diffusing weighted imaging and contrast-enhanced iron oxide MRI are explained. Imaging examples of the different modalities of benign and malignant transformed lymph nodes will be demonstrated. Furthermore, the diagnostic sensitivity of each modality will be delineated and further aspects of modern lymph node staging of the head and neck region such as those with special contrast agents will be described. These modern imaging modalities have sensitivity rates of 70-80% depending on the technical equipment and ability and on the experience of the investigator. The technique of near-infrared-imaging will be mentioned in another article in this journal. Also the value of biopsy techniques including recently developed ultrasonography guided needle biopsy with molecular analysis of the cells of about 97-100% accuracy in diagnosing benign from malignant lymph nodes will be mentioned. Overall, the reader will get an overview of the present imaging modalities to potentially stage correctly lymph nodes in the head and neck region to facilitate the therapeutic procedure.

Three-dimensional atlas of lymph node topography based on the visible human data set

Comprehensive atlases of lymph node topography are necessary tools to provide a detailed description of the lymphatic distribution in relation to other organs and structures. Despite the recent developments of atlases and guidelines focusing on definitions of lymphatic regions, a comprehensive and detailed description of the three-dimensional (3D) nodal distribution is lacking. This article describes a new 3D atlas of lymph node topography based on the digital images of the Visible Human Male Anatomical (VHMA) data set. About 1,200 lymph nodes were localized in the data set and their distribution was compared with data from current cross-sectional lymphatic atlases. The identified nodes were delineated and then labeled with different colors that corresponded to their anatomical locations. A series of 2D illustrations, showing discrete locations, description, and distribution of major lymph nodes, was compiled to form a cross-sectional atlas. The resultant contours of all localized nodes in the VHMA data set were superimposed to develop a volumetric model. A 3D reconstruction was generated for the lymph nodes and surrounding structures. The volumetric lymph node topography was also integrated into the existing VOXEL-MAN digital atlas to obtain an interactive and photo-realistic visualization of the lymph nodes showing their proximity to blood vessels and surrounding organs. The lymph node topography forms part of our whole body atlas database, which includes organs, definitions, and parameters that are related to radiation therapy. The lymph node topography atlas could be utilized for visualization and exploration of the 3D lymphatic distribution to assist in defining the target volume for treatment based on the lymphatic spread surrounding the primary tumor.

Role of sentinel node biopsy in the management and staging of the N0 neck

Sentinel node biopsy is being increasingly used as a staging tool for mucosal head and neck cancer. This review of the literature summarizes the results of research into the procedure when it has been performed in three main contexts: as part of an ipsilateral neck dissection, as a stand-alone procedure to stage the neck for positive or negative disease, and as a means of investigating the non-involved or contralateral neck in tumors close to or crossing the midline. The role of the procedure is discussed and the difficulties encountered are expanded, with a particular emphasis on pitfalls of the technique, caveats, and its potential role for the future.

Effectiveness of therapeutic (N1, N2) selective neck dissection (levels II to V) in patients with laryngeal and hypopharyngeal squamous cell carcinoma

BACKGROUND

The use of selective neck dissection (SND) in the treatment of clinically node-positive necks remains controversial.

METHODS

A total of 48 patients with laryngeal and hypopharyngeal carcinoma underwent 53 primary, therapeutic SNDs (levels II-V) and were retrospectively evaluated.

RESULTS

Regional metastases were staged as pN1 in 8 patients, pN2a in 3, pN2b in 29, and pN2c in 8. Of the primarily treated necks 45 of 53 (85%) were irradiated postoperatively. Extracapsular spread was found in 27 neck specimens (51%). Regional recurrences in level I occurred in one patient (1.8%) and in level II-V in 5 patients (9.4%). The actuarial overall survival at 4 years was 36.5%.

CONCLUSIONS

In selected cases therapeutic SND (levels II-V) in node positive (N1,2) patients with laryngeal or hypopharyngeal carcinoma does not lead to increased risk for recurrence in level I or other levels of the neck and is therefore a safe procedure.

Indium-111-Octreotide scintigraphy in differentiated thyroid carcinoma metastases that do not respond to treatment with high-dose I-131

AIM

Differentiated thyroid cancer is characterized by a very good prognosis in the majority of the patients. The therapy of choice is surgery followed by ablation with Iodine-131 (I-131). However, some patients have metastases that have lost the capability of concentrating I-131, even when it is given in therapeutic doses. In the present study, we describe the value of Indium-111 Octreotide (Octreoscan) in differentiated thyroid cancer patients with increased Tg levels who failed to demonstrate a response to treatment with high-dose I-131.

METHOD

Fifteen consecutive patients with progressive differentiated thyroid cancer (ten female, five male) (mean age: 59 years, range 13-81 years; eight papillary, six follicular, and one Hürthle cell carcinoma) were studied. Progression was based on increasing Tg levels and was confirmed by radiological evaluation. Whole body scintigraphy (WBS) was performed after the administration of 200 MBq of Indium-111-Octreotide. The images were assessed by two experienced observers and compared with post-treatment I-131 WBS.

RESULTS

In seven out of 15 patients distant metastases were already present at initial stage, whereas in ten patients the primary tumor stage was T3 or T4 indicating that the majority of the patients had advanced disease. In two out of five patients with a positive I-131 WBS, Indium-111-Octreotide was false negative. In nine out of ten patients with a negative I-131 WBS, Indium-111-Octreotide demonstrated multiple metastases. In those patients with a positive SSR-scintigraphy, metastases were found in the lungs ( n=14), bone ( n=7), mediastinum ( n=3), liver ( n=2), brains ( n=1), and cutis ( n=1). Overall, three out of 15 patients had a negative Indium-111-Octreotide result revealing a sensitivity of 80%.

CONCLUSION

Our findings demonstrate the diagnostic value of Indium-111-Octreotide in differentiated thyroid cancer that fails to respond to I-131 treatment. It opens the possibility for additional treatment with high doses of Indium-111-Octreotide or its analogs in a majority of the patients.