Lymph node metastases: CT and MRI

The prognostic value of lymphatic metastatic size in head and neck squamous cell carcinoma

BACKGROUND

Lymphatic metastatic size was proved to predict prognosis in different types of carcinomas, except in head and neck squamous cell carcinoma (HNSCC) located in hypopharynx, oropharynx and supraglottic region et al. The aim of this study is to evaluate the prognostic value of lymphatic metastatic size in HNSCC, which may guide clinical decision-making in practice.

METHODS

From 2008 to 2022, 171 patients, who were diagnosed as HNSCC in our center, were included. The demographic data, clinicopathological characteristics and lymphatic metastatic size were recorded and analyzed using the Kaplan-Meier method and Cox regression analysis.

RESULTS

Among 171 patients, 107 cases were hypopharyngeal cancer, 38 cases supraglottic cancer and 26 cases oropharyngeal cancer. The median of lymphatic metastatic size was 8 mm (range 0-46). According to lymphatic metastatic size, the patients were assigned to three subgroups: Group I (0 mm), Group II ( ≤ 10 mm) and Group III (> 10 mm). Kaplan-Meier analysis with log rank test revealed that Group I and Group II had similar locoregional control rate, distant metastasis free probability, disease-free survival and overall survival (all p > 0.05), whereas Group III had significant worse prognosis. Adjusted for demographic and other clinicopathological characteristics, lymphatic metastatic size was an independent predictor of disease-free survival and overall survival in HNSCC.

CONCLUSIONS

Lymphatic metastatic size was an independently prognostic factor in HNSCC, which may assist in postoperative adjuvant treatment decisions.

Postoperative radiotherapy for supraglottic cancer on real-world data: can we reduce dose to lymph node levels?

PURPOSE

To evaluate prognosis for reducing postoperative radiotherapy (PORT) dose to lymph node levels of supraglottic cancer (SC) on real-world data.

METHOD AND MATERIALS

Patients were derived from two cancer centers. In center 1, the involved nodal levels (high-risk levels, HRL) and the next level received a dose of 60.06 Gy/1.82 Gy per fraction, while the other uninvolved levels (low-risk levels, LRL) received 50.96 Gy/1.82 Gy per fraction. In center 2, all received 50 Gy/2 Gy per fraction. The rates of high-risk levels control (HRC), regional control (RC), overall survival (OS), progression-free survival (PFS) and distant metastasis-free survival (DMFS) were calculated by Kaplan-Meier method.

RESULT

Totally, 124 patients were included (62 in center 1, 62 in center 2). Most patients (106, 85.5%) had a stage T3/N + tumor. The median follow-up was 45 months (range 1-163 months). There were no significant differences in terms of OS (p = 0.126), RC (p = 0.514), PFS (p = 0.195) and DMFS (p = 0.834). Most regional recurrences (4, 80%) occurred within three years of treatment, and all occurred within the target volumes. No regional failure occurred in HRL in center 1, while three (3/4) failures occurred in center 2. Dose reduction prescription to HRL led to a lower HRC rate (100% vs. 90.6%, p = 0.009). While the rates of LRL control (98.4%) were equal between the two centers.

CONCLUSION

Compared with a standard dose, the reduced dose to involved nodal levels showed inferior regional control for PORT, while uninvolved nodal levels showed equal outcomes. A dose of 50 Gy for HRL may be an unfavorable treatment option for SC.

ADC Values of Cytologically Benign and Cytologically Malignant 18 F-FDG PET-Positive Lymph Nodes of Head and Neck Squamous Cell Carcinoma

Simple Summary

In squamous cell carcinoma of the head and neck, 18F-fluordeoxyglucose positron emission tomography (FDG-PET), diffusion-weighted magnetic resonance imaging (DW-MRI) and ultrasound-guided fine needle aspiration are commonly used imaging tools for nodal staging (N-staging). Although FDG-PET has good performance in nodal detection, it is still difficult to distinguish between PET-positive reactive and malignant nodes for the purpose of selecting nodes to be aspirated. DW-MRI can help to detect small lymph node metastases, and an inverse correlation with FDG uptake is expected. We found a mild negative correlation between SUVmax and ADC. Comparing the apparent diffusion coefficient (ADC) values between PET-positive and PET-negative nodes, ADC was significantly higher in PET-negative nodes. Whereas no significantly lower ADC value of cytological malignant nodes could be found overall, in the subgroup of non-HPV-related nodes, the ADC values of cytologically malignant PET-positive nodes were significantly lower than in cytologically benign nodes. This finding might be helpful in selecting nodes for puncture.

Abstract

Nodal staging (N-staging) in head and neck squamous cell carcinoma (HNSCC) is essential for treatment planning and prognosis. 18F-fluordeoxyglucose positron emission tomography (FDG-PET) has high performance for N-staging, although the distinction between cytologically malignant and reactive PET-positive nodes, and consequently, the selection of nodes for ultrasound-guided fine needle aspiration cytology (USgFNAC), is challenging. Diffusion-weighted magnetic resonance imaging (DW-MRI) can help to detect nodal metastases. We aim to investigate the potential of the apparent diffusion coefficient (ADC) as a metric to distinguish between cytologically reactive and malignant PET-positive nodes in order to improve node selection criteria for USgFNAC. PET-CT, real-time image-fused USgFNAC and DW-MRI to calculate ADC were available for 78 patients offered for routine N-staging. For 167 FDG-positive nodes, differences in the ADC between cytologically benign and malignant PET-positive nodes were evaluated, and both were compared to the ADC values of PET-negative reference nodes. Analyses were also performed in subsets of nodes regarding HPV status. A mild negative correlation between SUVmax and ADC was found. No significant differences in ADC values were observed between cytologically malignant and benign PET-positive nodes overall. Within the subset of non-HPV-related nodes, ADC_b0-200-1000 was significantly lower in cytologically malignant PET-positive nodes when compared to benign PET-positive nodes. ADC_b0-1000 and ADCb_0-200-1000 were significantly lower (p = 0.018, 0.016, resp.) in PET-negative reference nodes than in PET-positive nodes. ADC was significantly higher in PET-negative reference nodes than in PET-positive nodes. The non-HPV-related subgroup showed significantly (p = 0.03) lower ADC values in cytologically malignant than in cytologically benign PET-positive nodes, which should help inform the node selection procedure for puncture.

Development and validation of a nomogram for prediction of cervical lymph node metastasis in middle and lower thoracic esophageal squamous cell carcinoma

Background

Estimates of cervical lymph node (LN) metastasis in patients with middle and lower thoracic esophageal squamous cell carcinoma (ESCC) are important. A nomogram is a useful tool for individualized prediction.

Methods

A total of 235 patients were enrolled in this study. Univariate and multivariate analyses were performed to screen for independent risk factors and construct a nomogram to predict the risk of cervical LN metastasis. The nomogram performance was assessed by discrimination, calibration, and clinical use.

Results

Totally, four independent predictors, including the maximum diameter of tumor, paraesophageal lymph node status, recurrent laryngeal nerve lymph node status, and the CT-reported cervical LN status, were enrolled in the nomogram. The AUC of the nomogram model in the training and validation dataset were 0.833 (95% CI 0.762–0.905), 0.808 (95% CI 0.696–0.920), respectively. The calibration curve demonstrated a strong consistency between nomogram and clinical findings in predicting cervical LN metastasis. Decision curve analysis demonstrated that the nomogram was clinically useful.

Conclusion

We developed a nomogram that could be conveniently used to predict the individualized risk of cervical LN metastasis in patients with middle and lower thoracic ESCC.

In Vitro Studies Regarding the Safety of Chitosan and Hyaluronic Acid-Based Nanohydrogels Containing Contrast Agents for Magnetic Resonance Imaging

The aim of this study was to investigate the biocompatibility of contrast agents, such as gadolinium 1, 4, 7, 10 tetraazacyclo-dodecane tetraacetic acid (GdDOTA) and gadolinium dioctyl terephthalate (GdDOTP), encapsulated in a polymeric matrix containing chitosan and hyaluronic acid using RAW264.7 murine macrophages and human blood samples. The cell viability and cytotoxicity were evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and lactate dehydrogenase (LDH) assays, while cell cycle analysis was determined in RAW264.7 cells using flow cytometry. The mitochondrial membrane potential (MMP), hemolytic index, complement activation, and thrombogenic potential of gadolinium (Gd) containing nanohydrogels were measured by fluorometric and spectrophotometric methods. Taken together, our results demonstrate the good bio- and hemocompatibility of chitosan-based nanohydrogels with the RAW264.7 cell line and human blood cells, suggesting that these could be used as injectable formulations for the magnetic resonance imaging diagnostic of lymph nodes.

Assessment of the Diagnostic Accuracy of Baseline Clinical Examination and Ultrasonographic Imaging for the Detection of Lymph Node Metastasis in Patients With High-risk Cutaneous Squamous Cell Carcinoma of the Head and Neck

IMPORTANCE

Patients with cutaneous squamous cell carcinoma (SCC) of the head and neck may develop lymph node metastasis; therefore, additional workup of the regional lymph nodes in these patients should be considered. However, there is uncertainty regarding the value of baseline ultrasonographic imaging in addition to clinical examination for the detection of metastasis.

OBJECTIVE

To assess the diagnostic accuracy of clinical examination and baseline ultrasonography for the detection of metastasis among patients with high-risk cutaneous SCC of the head and neck and to assess the accuracy of ultrasonography when baseline clinical examination produces negative results.

DESIGN, SETTING, AND PARTICIPANTS

This diagnostic study was conducted among a retrospective cohort of 233 patients with 246 high-risk cutaneous SCC tumors of the head and neck. The study included all patients with high-risk cutaneous SCC of the head and neck who received clinical examination and baseline ultrasonographic imaging of their lymph nodes at the Erasmus Medical Center Cancer Institute, a tertiary referral hospital for patients with skin cancer in Rotterdam, the Netherlands, between January 1, 2015, and December 31, 2017. Data were analyzed from October 13, 2020, to September 29, 2021.

MAIN OUTCOMES AND MEASURES

Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated. Fine-needle aspiration cytologic biopsy and 6 months of follow-up per patient were used as the reference standards.

RESULTS

Among 233 patients (176 men [75.5%]; median age, 79.1 years [IQR, 71.5-83.7 years]; data on race and ethnicity were not collected) with 246 high-risk cutaneous SCC tumors of the head and neck, 20 metastases were cytologically confirmed at baseline, and 2 metastases were detected during 6 months of follow-up, yielding a 9% metastasis rate. The sensitivity of clinical examination was 50% (95% CI, 28%-72%), and the specificity was 96% (95% CI, 93%-98%). The PPV and NPV were 55% (95% CI, 36%-72%) and 95% (95% CI, 93%-97%), respectively. In the total cohort, ultrasonography had a sensitivity of 91% (95% CI, 71%-99%) and a specificity of 78% (95% CI, 72%-83%), with a PPV of 29% (95% CI, 23%-35%) and an NPV of 99% (95% CI, 96%-100%). In the group of patients with negative results at baseline clinical examination, 9 of 11 metastases were detected by ultrasonography, with 82% sensitivity (95% CI, 48%-98%); specificity was 79% (95% CI, 73%-84%), PPV was 17% (95% CI, 12%-23%), and NPV was 99% (95% CI, 96%-100%).

CONCLUSIONS AND RELEVANCE

In this diagnostic study, among a cohort of patients with high-risk cutaneous SCC of the head and neck, baseline ultrasonography was more sensitive than clinical examination alone for the detection of lymph node metastasis. In the setting of a negative result at baseline clinical examination, ultrasonography had high sensitivity for detecting nodal metastases, but this sensitivity should be evaluated against the high rate of false-positive findings.

Diagnostic value of magnetic resonance imaging in cervical lymph node metastasis of oral squamous cell carcinoma

OBJECTIVE

The objective of this study was to investigate the correlation between magnetic resonance imaging (MRI) characteristics of cervical lymph nodes and the pathologically confirmed status of cervical lymph node metastasis (LNM) in oral squamous cell carcinoma (OSCC) and to provide imaging evaluation parameters for the clinical diagnosis of cervical lymph node status in OSCC.

STUDY DESIGN

In a retrospective analysis, 79 patients who were first pathologically diagnosed with OSCC were included. The MRI-derived imaging parameters of the cervical lymph nodes were evaluated and the pathological status of lymph nodes in neck dissection specimens was reviewed. The relationship between the imaging parameters and cervical LNM was analyzed.

RESULTS

The MRI-derived imaging parameters of 4419 lymph nodes were evaluated, and the pathological status of 2463 lymph nodes was reviewed. The MRI-derived shortest axial diameter (SAD) and unclear boundary of the cervical lymph node were significantly related to LNM. The cutoff value of SAD that enabled identification of LNM was 3.6 mm, and it was 4.2 and 4.1 mm for the prediction of overall survival and disease-specific survival, respectively.

CONCLUSIONS

The MRI-derived parameters SAD and unclear boundary of the cervical lymph node correlated with LNM in OSCC. MRI-derived SAD larger than 3 mm warrants simultaneous neck dissection at initial surgery.

Subphrenic Lymph Node Metastasis Predicts Poorer Prognosis for Nasopharyngeal Carcinoma Patients With Metachronous Metastasis

Aim

We retrospectively analyzed the distribution of distant lymph node metastasis and its impact on prognosis in patients with metastatic NPC after treatment.

Methods

From 2010 to 2016, 219 NPC patients out of 1,601 (182 from the Affiliated Cancer Hospital and Institute of Guangzhou Medical University, and 37 from the Affiliated Dongguan Hospital, Southern Medical University) developed distant metastasis after primary radiation therapy. Metastatic lesions were divided into groups according to location: bones above the diaphragm (supraphrenic bone, SUP-B); bones below the diaphragm (subphrenic bone, SUB-B); distant lymph nodes above the diaphragm (supraphrenic distant lymph nodes, SUP-DLN); distant lymph nodes below the diaphragm (subphrenic distant lymph nodes, SUB-DLN), liver, lung, and other lesions beyond bone/lung/distant lymph node above the diaphragm (supraphrenic other lesions, SUP-OL); other lesions beyond bone/liver/distant lymph node below the diaphragm (subphrenic other lesions, SUB-OL); the subtotal above the diaphragm (supraphrenic total lesions, SUP-TL); and the subtotal below the diaphragm (subphrenic total lesions, SUB-TL). Kaplan–Meier methods were used to estimate the probability of patients’ overall survival (OS). Univariate and multivariate analyses were applied using the Cox proportional hazard model to explore prediction factors of OS.

Results

The most frequent metastatic locations were bone (45.2%), lung (40.6%), liver (32.0%), and distant lymph nodes (20.1%). The total number of distant lymph node metastasis was 44, of which 22 (10.0%) were above the diaphragm, 18 (8.2%) were below the diaphragm, and 4 (1.8%) were both above and below the diaphragm. Age (HR: 1.02, 95% CI: 1.00, 1.03, p = 0.012), N stage (HR: 1.26, 95% CI: 1.04, 1.54, p = 0.019), number of metastatic locations (HR: 1.39, 95% CI: 1.12, 1.73, p = 0.003), bone (HR: 1.65, 95% CI: 1.20, 2.25, p = 0.002), SUB-B (HR: 1.51, 95% CI: 1.07, 2.12, p = 0.019), SUB-DLN (HR: 1.72, 95% CI: 1.03, 2.86, p = 0.038), and SUB-O L(HR: 4.46, 95% CI: 1.39, 14.3, p = 0.012) were associated with OS. Multivariate analyses revealed that a higher N stage (HR: 1.23, 95% CI: 1.00, 1.50, p = 0.048), SUB-DLN (HR: 1.72, 95% CI: 1.02, 2.90, p = 0.043), and SUB-OL (HR: 3.72, 95% CI: 1.14, 12.16, p = 0.029) were associated with worse OS.

Conclusion

Subphrenic lymph node metastasis predicts poorer prognosis for NPC patients with metachronous metastasis; however, this needs validation by large prospective studies.

Combining machine learning and texture analysis to differentiate mediastinal lymph nodes in lung cancer patients

Evaluate whether texture analysis associated with machine learning approaches could differentiate between malignant and benign lymph nodes. A total 18 patients with lung cancer were selected, with 39 lymph nodes, being 15 malignant and 24 benign. Retrospective computed tomography scans were utilized both with and without contrast medium. The great differential of this work was the use of 15 textures from mediastinal lymph nodes, with five different physicians as operators. First and second order statistical textures such as gray level run length and co-occurrence matrix were extracted and applied to three different machine learning classifiers. The best machine learning classifier demonstrated a variability of less than 5% among operators. The support vector machine (SVM) classifier presented 95% of the area under the ROC curve (AUC) and 89% of sensitivity for sequences without contrast medium. SVM classifier presented 93% of AUC and 86% of sensitivity for sequences with contrast medium. Texture analysis and machine learning may be helpful in the differentiation between malign and benign lymph nodes. This study can aid the physician in diagnosis and staging of lymph nodes and potentially reduce the number of invasive analysis to histopathological confirmation.

Multiple Primary Malignant Neoplasms: A Case Report of Breast Mucinous Carcinoma and Extramammary Diffuse Large B-Cell Lymphoma in a Male Patient

Multiple primary malignant neoplasms refer to two or more malignancies in an individual that are not related. We report a case of a 78-year-old male with concurrent breast mucinous carcinoma and extramammary lymphoma. The patient initially presented with palpable masses in the left breast and the right groin, which were pathologically confirmed after a surgical biopsy as breast mucinous carcinoma and diffuse large B-cell lymphoma, respectively. He underwent whole-body 18-fluorine deoxyglucose PET/CT before surgery, and an enhancing nodular lesion in the left lingual tonsil was found incidentally. It was later confirmed as a diffuse large B-cell lymphoma, a pathology of the same type as the right inguinal mass. Unspecified lymphadenopathies in breast cancer patients may easily be considered as metastatic lesions. However, this case suggests that lymphomas should be included in the differential diagnoses to avoid misdiagnosis and treatment delay, especially in older adult patients.

Photoacoustic Molecular Imaging for the Identification of Lymph Node Metastasis in Head and Neck Cancer Using an Anti-EGFR Antibody-Dye Conjugate

The presence of lymph node (LN) metastases is an essential prognostic indicator in patients with head and neck squamous cell carcinoma (HNSCC). This study assessed photoacoustic molecular imaging (PAMI) of the antiepidermal growth factor receptor antibody (panitumumab) conjugated to a near-infrared fluorescent dye, IRDye800CW (panitumumab-IRDye800CW; pan800), for the identification of occult metastatic LNs in patients with HNSCC (n = 7). Methods: After in vitro photoacoustic imaging characterization of pan800, PAMI was performed on excised neck specimens from patients infused with pan800 before surgery. Freshly obtained neck specimens were imaged with 3-dimensional, multiwavelength spectroscopic PAMI (wavelengths of 680, 686, 740, 800, 860, 924, and 958 nm). Harvested LNs were then imaged with a closed-field near-infrared fluorescence imager and histologically examined by the pathologist to determine their metastatic status. Results: In total, 53 LNs with a maximum diameter of 10 mm were analyzed with photoacoustic and fluorescence imaging, of which 4 were determined to be metastatic on the final histopathologic report. Photoacoustic signals in the LNs corresponding to accumulated pan800 were spectrally unmixed using a linear least-square-error classification algorithm. The average thresholded photoacoustic signal intensity corresponding to pan800 was 5-fold higher for metastatic LNs than for benign LNs (2.50 ± 1.09 arbitrary units [a.u.] vs. 0.53 ± 0.32 a.u., P < 0.001). Fluorescence imaging showed that metastatic LNs had a 2-fold increase in fluorescence signal compared with benign LNs ex vivo (P < 0.01, 0.068 ± 0.027 a.u. vs. 0.035 ± 0.018 a.u.). Moreover, the ratio of the average of the highest 10% of the photoacoustic signal intensity over the total average, representative of the degree of heterogeneity in the pan800 signal in LNs, showed a significant difference between metastatic LNs and benign LNs (11.6 ± 13.4 vs. 1.8 ± 0.7, P < 0.01) and an area under the receiver-operating-characteristic curve of 0.96 (95% CI, 0.91-1.00). Conclusion: The data indicate that PAMI of IRDye800-labeled tumor-specific antibody may have the potential to identify occult LN metastasis perioperatively in HNSCC patients.

Diagnostic value of 3D dynamic contrast-enhanced magnetic resonance imaging in lymph node metastases of head and neck tumors: a correlation study with histology

Background

Accurate staging of cervical lymph nodes (LN) is pivotal for further clinical management of patients with head and neck cancer. Functional magnetic resonance imaging (MRI) such as three-dimensional (3D) dynamic contrast-enhanced (DCE) acquisition might improve the diagnosis of cervical LN metastases.

Purpose

To evaluate the additional diagnostic value of high-resolution 3D T1-weighted DCE in detecting LN metastasis compared to standard morphological imaging criteria in patients with head and neck tumors as correlated to histopathology.

Material and Methods

Standard MRI with 3D DCE acquisition at voxel sizes of 1 × 1×1 mm was performed in 15 patients before surgery; 92 LN of the head and neck were histopathologically analyzed. A logistic regression analysis of semi-quantitative DCE parameters, time-intensity curve (TIC) shapes, and morphological criteria was performed to differentiate benign from malignant LN.

Results

Standard MRI was sufficient for diagnosis of malignancy in LN with a short-axis diameter ≥ 15 mm (n = 17). For LN metastases with a short-axis diameter <15 mm (n = 12), however, the combination of 3D DCE MRI parameters, TIC shapes, and LN diameter significantly increased the sensitivity and specificity of diagnosing metastases (DCE + TIC shape + LN diameter: 92% and 88% vs. DCE only: 83% and 68% (P < 0.01) vs. LN diameter only: 83% and 77% (P = 0.04).

Conclusion

MRI including isotropic high-resolution 3D DCE acquisition combined with morphological criteria allows an accurate assessment of small cervical LN metastases in patients with head and neck cancer. For LN ≥ 15 mm diameter, morphologic imaging may suffice to diagnose metastatic disease to the LN.

Two separate tumours-Concomitant papillary carcinoma in thyroglossal duct cyst and right thyroid lobe: Case report and review of the literature

•

Thyroglossal duct cyst carcinoma concurrent with another thyroid gland carcinoma as two separate tumours are rare.

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Ultrasound scan and ultrasound-guided fine needle aspiration and cytology are useful for diagnosis and for follow up.

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Excision of thyroglossal duct cyst carcinoma and total thyroidectomy is ideal treatment option to facilitate future radioactive iodine ablation if required.

Introduction

Malignancy of thyroglossal duct cyst (TGDC) is rare, usually as papillary carcinoma, and less frequently as squamous cell or follicular carcinoma. TGDC carcinoma can present as a mass arising from the neck, with or without compression symptoms. Papillary carcinoma in TGDC concomitant with another papillary carcinoma in the thyroid gland is extremely rare.

Presentation of case

: 31 years old female with a neck lump since 2 years, slowly increasing in size, with mild pain while drinking fluids, and no change of voice. No past history of neck irradiation or family history of thyroid cancers. Ultrasonography of the neck showed TGDC and right thyroid nodule. Ultrasound guided fine needle aspiration and cytology of the TGDC showed TGDC papillary carcinoma. The patient underwent Sistrunk’s procedure and total thyroidectomy.

Discussion

Rare case of classic papillary carcinoma arising in TGDC, concomitant with another papillary carcinoma in the right thyroid nodule. Preoperative work up included US and fine needle aspiration and cytology (FNAC). Post-operative histopathology showed papillary carcinoma in the TGDC; and another in the right thyroid lobe that was a papillary carcinoma with follicular patterns.

Conclusions

TGDC carcinoma concurrent with another carcinoma in the right thyroid lobe as two separate tumours are extremely rare. All patients should undergo Sistrunk’s procedure, and total thyroidectomy for the thyroid tumour. Follow-up requires thyroxine replacement therapy to treat hypothyroidism and to suppress TSH in order to prevent recurrence; and neck ultrasound and thyroglobulin tumour marker to detect recurrence if present.

Diffusion-weighted MRI: impact of the size of the ROI in detecting metastases in subcentimeter lymph nodes in head and neck squamous cell carcinoma

PURPOSE

Our aim is to determine the impact of the size of ROI in detecting subcentimeter metastatic lymph nodes in patients with head and neck squamous cell carcinoma (HNSCC). Secondary aim is to determine the impact of the histopathologic grade of the primary cancer on the ADC value of the metastatic nodes.

METHODS

The prospective study included 51 patients with histopathologically proven HNSCC at the primary site. Primary site includes oral cavity, oropharynx, larynx, and hypopharynx. ADC values of the lymph nodes were measured on ADC maps by placing two ROIs in the lymph nodes (0.2 cm² in the center of the node and the whole node). Lymph nodes were dissected by levels, marked by the surgeon, and sent to the pathologist.

RESULTS

By applying a smaller ROI, ADC values have greater sensitivity, specificity, NPV, PPV, and AUC in detecting metastasis compared to the ADC value of the entire node (88.0%, 80.73%, 90.7%, 75.9%, 0.912% versus 80.0%, 77.98%, 85% ,71.4%, and 0.819%, respectively) p < 0.001. Statistically significant negative correlation was established between the tumor grade and the ADC of lymph node at ROI 0.2 cm²and ROI of the whole lymph node (rho = - 0.425; p = 0.002, and rho = - 0.298; p = 0.038, respectively).

CONCLUSION

ROI size affects the ADC value of the nodes. The higher histopathological grade of the primary tumor is inversely correlated with the ADC value of the lymph nodes.

Cervical necrotic lymphadenopathy: a diagnostic tree analysis model based on CT and clinical findings

OBJECTIVES

To establish a diagnostic tree analysis (DTA) model based on computed tomography (CT) findings and clinical information for differential diagnosis of cervical necrotic lymphadenopathy, especially in regions where tuberculous lymphadenitis and Kikuchi disease are common.

METHODS

A total of 290 patients (147 men and 143 women; mean age (years), 46.2 ± 19.5; range, 3-91) with pathologically confirmed metastasis (n = 110), tuberculous lymphadenitis (n = 73), Kikuchi disease (n = 71), and lymphoma (n = 36) who underwent contrast-enhanced neck CT were included. The patients were randomly divided into training (86%, 248/290) and validation (14%, 42/290) datasets to assess diagnostic performance of the DTA model. Two sorts of DTA models were created using a classification and regression tree algorithm on the basis of CT findings alone and that combined with clinical findings.

RESULTS

In the DTA model based on CT findings alone, perinodal infiltration, number of the necrotic foci, percentage of necrotic lymph node (LN), degree of necrosis, margin and shape of the necrotic portion, shape of the LN, and enhancement ratio (cutoff value, 1.93) were significant predictors for differential diagnosis of cervical necrotic lymphadenopathy. The overall accuracy was 80.6% and 73.8% in training and validation datasets. In the model based on imaging and clinical findings, tenderness, history of underlying malignancy, percentage of necrotic LN, degree of necrosis, and number of necrotic foci were significant predictors. The overall accuracy was 87.1% and 88.1% in training and external validation datasets.

CONCLUSIONS

The DTA model based on CT imaging and clinical findings may be helpful for the diagnosis of cervical necrotic lymphadenopathy.

KEY POINTS

• The diagnostic tree analysis model based on CT may be useful for differential diagnosis of cervical necrotic lymphadenopathy. • Perinodal infiltration, number of necrotic foci, percentage of necrotic lymph nodes, degree of necrosis, margin and shape of necrotic portion, lymph node shape, and enhancement ratio were the most significant predictors.

Diagnosis of cervical lymph node metastases in head and neck cancer with ultrasonic measurement of lymph node volume

OBJECTIVE

The purpose of this study was to evaluate the usefulness of ultrasound (US) volume measurement of the cervical lymph nodes for diagnosing nodal metastasis in patients with head and neck cancer using a node-by-node comparison.

METHODS

Thirty-four consecutive patients with head and neck cancer from one tertiary university hospital were prospectively enrolled from 2012 to 2017. Patients with histologically proven squamous cell primary tumors in the head and neck region scheduled to undergo a therapeutic neck dissection were eligible. For each patient, 1-4 target lymph nodes were selected from the planned neck dissection levels. Lymph nodes with thickness >20 mm or in a cluster were excluded. Node-by-node comparisons between the pre-operative US assessment, the post-operative actual measurements and histopathological results were performed for all target lymph nodes. Quantitative measurements, such as three diameters, ratios of the three diameters and volume were analyzed in this study. Lymph node volume was calculated using the ellipsoid formula.

RESULTS

Patients comprised 28 men and 6 women with a mean age of 60.0 years (range, 29-80 years) at the time of surgery. In total, 67 target lymph nodes were analyzed in this study and the thickness ranged from 3.9 to 20.0 mm (mean 8.0 mm). There was a strong correlation between the US volume and post-operative actual volume (ρ = 0.87, p < 0.01). The US volume measured 2156 ± 2156 mm³ for the tumor positive nodes, which was significantly greater than the US volume of 512 ± 315 mm³ for tumor negative nodes (p < 0.01). Significant differences between tumor positive and tumor negative nodes were found in five variables (volume, thickness, major axis, minor axis and ratio of minor axis to thickness) for total lymph nodes. To identify predictors of lymph node metastasis, ROC curves of the US variables of target lymph nodes were compared, of which 4 variables were considered acceptable for predicting the lymph node metastasis: volume (AUC 0.86), thickness (AUC 0.86), major axis (AUC 0.79), and minor axis (AUC 0.79) for total lymph nodes. The optimal cut-off level for US volume in total lymph nodes was found to be 1242 mm³, whereby a 62% sensitivity and 98% specificity was reached (likelihood ratio: 25.2).

CONCLUSION

Pre-operative ultrasonic volume measurement of the cervical lymph nodes was useful for early detection of cervical nodal metastasis in head and neck cancer.

The assessment of the accuracy of clinical preoperative lymph node

PURPOSE

The aim of the present study is to assess the accuracy of clinical preoperative lymph node and to define the degree of relation between the clinical preoperative assessment and histopathological examination in patients with head and neck cancer and cN+.

METHODS

This retrospective study was performed on 125 patients (85 males and 40 females) at the Department of Oral and Maxillofacial Surgery, the First Affiliated Hospital of Zhengzhou University, between December 2012 and December 2014.

RESULT

Of all the patients who underwent neck dissection, 37 were found with no neck metastasis. Positive or suspected lymph nodes were detected at computed tomography (CT) in 44 and detected at ultrasonogram diagnosis (USG) in 38 of 125 patients, and the necks were assessed as normal in 55 (44%) by both USG and CT.

CONCLUSION

Further investigation is needed to evaluate the rates of overall survival and disease-free survival of these N0 patients with neck dissection.

Preoperative evaluation of cervical lymph nodes for metastasis in patients with oral squamous cell carcinoma: A comparative study of efficacy of palpation, ultrasonography and computed tomography

INTRODUCTION

Oral cancer is a major health threat in a country like India, where patients frequently present with advanced disease with regional dissemination to cervical lymph nodes. The management and prognosis depend on the status of cervical lymph nodes. Thus, it becomes imperative to diagnose and evaluate them preoperatively.

AIM

This study aims to compare the efficacy of palpation, ultrasonography (USG) and computed tomography (CT) in the preoperative evaluation of cervical lymph node for metastasis in patients with oral squamous cell carcinoma.

SETTINGS

Department of Oral and Maxillofacial Surgery, SCB Dental College and Hospital, Cuttack, Odisha, India.

METHODOLOGY

A total of thirty patients of either sex of age group 20-70 years, diagnosed with oral cancer were randomly selected for the study and subjected to palpation, USG and computer tomography followed by histopathology for confirmation. The results were evaluate statistically by sensitivity, specificity, positive predictive value, and negative predictive value and accuracy.

RESULTS

For level IA palpation, USG and CT were equally sensitive (100%) and specific (100%). Although palpation, USG and CT were equally sensitive (80%) for level IB, the specificity of palpation (70%) <USG (95%) = CT (95%). For level II sensitivity of palpation (25%) <USG (75%) <CT (100%) whereas specificity was CT (84.6%) <palpation (92.3%) <USG (100%).

CONCLUSION

CT (96.1%) and USG (97.7%) were more accurate than palpation (92.7%), for detection of metastasis in cervical lymph nodes in patients with oral squamous cell carcinoma. CT along with USG should be used for accurate preoperative evaluation of cervical lymph node.

Tissue factor-specific ultra-bright SERRS nanostars for Raman detection of pulmonary micrometastases

Here we demonstrate a novel application of 'surface enhanced resonance Raman scattering nanoparticles' (SERRS NPs) for imaging breast cancer lung metastases with much higher precision than currently feasible. A breast cancer lung metastasis mouse model was established by intravenous injection of LM2 cells. These mice were intravenously administered SERRS NPs conjugated with ALT-836, an anti-tissue factor (TF) monoclonal antibody, and subjected to Raman imaging to visualize the expression of TF both in vivo and ex vivo. Raman imaging indicated marked uptake of αTF-SERRS-NPs by the lung metastases compared to isotype and blocking controls. Conversely, little uptake of αTF-SERRS-NPs was observed in the lungs of healthy mice. Successful detection and delineation of pulmonary micrometastatic lesions as small as 200 μm, corroborated by histology, immunohistochemistry, and bioluminescence imaging confirmed the suitability of both TF as a target and αTF-SERRS-NPs as an effective contrast agent for imaging breast cancer lung metastases. Further advancements of this technique in the form of Raman endoscopes coupled with ultrabright SERRS NPs developed in this work could lead to minimally invasive detection and resection of lung metastases.

Is there an additive value of 18 F-FDG PET-CT to CT/MRI for detecting nodal metastasis in oropharyngeal squamous cell carcinoma patients with palpably negative neck?

Background Cervical node metastasis is one of the most significant prognostic factors in patients with oropharyngeal squamous cell carcinoma (SCC). There is little information regarding the comparison of histopathologic analysis following neck dissection with imaging results in oropharyngeal SCC. Purpose To investigate the clinical utility of PET-CT compared with computed tomography (CT) or magnetic resonance imaging (MRI) for detecting nodal metastasis in oropharyngeal SCC patients with palpably negative neck and to investigate whether pretreatment imaging modalities support the rationale for elective neck treatment. Material and Methods A total of 49 oropharyngeal SCC patients with palpably negative neck (42 men, 7 women; average age, 59.1 years) underwent primary tumor resection and neck dissection as a primary treatment. All patients were preoperatively evaluated with PET-CT and CT/MRI, and the diagnostic accuracy of each imaging modality was assessed by comparison with histopathologic results of the surgical specimen. Results Twenty-five (51.0%) of our 49 patients had neck metastases. On a level-by-level analysis, the sensitivity of PET-CT, CT/MRI, and a combination of PET-CT and CT/MRI was 54.6%, 54.6%, and 60.6%, respectively, at all neck levels. The area under the ROC showed that the diagnostic performance of the combined interpretation was not significantly different from that of CT/MRI alone (0.780 vs. 0.750, respectively; P = 0.158) and PET-CT alone (0.780 vs. 0.765, respectively; P = 0.501). Conclusion Addition of PET-CT to CT/MRI did not provide better diagnostic accuracy for detecting nodal metastasis in preoperative evaluation of oropharyngeal SCC patients with palpably negative neck, suggesting that current imaging studies might not replace elective neck dissection.

MRI sequences for the detection of individual lymph nodes in regional breast radiotherapy planning

OBJECTIVE

In regional radiotherapy (RT) for patients with breast cancer, lymph node (LN) targets are delineated on CT, defined by anatomical boundaries. By identifying individual LNs, MRI-based delineations may reduce target volumes and thereby toxicity. We optimized MRI sequences for this purpose. Our aim was to evaluate the techniques for LN delineation in RT planning.

METHODS

Supine MRI was explored at 1.5 T in RT position (arms in abduction). 5 MRI techniques were optimized in 10 and evaluated in 12 healthy female volunteers. The scans included one T1 weighted (T1w), three T2 weighted (T2w) and a diffusion-weighted imaging (DWI) technique. Quantitative evaluation was performed by scoring LN numbers per volunteer and per scan. Qualitatively, scans were assessed on seven aspects, including LN contrast, anatomical information and insensitivity to motion during acquisition.

RESULTS

Two T2w fast spin-echo (FSE) methods showed the highest LN numbers (median 24 axillary), high contrast, excellent fat suppression and relative insensitivity to motion during acquisition. A third T2w sequence and DWI showed significantly fewer LNs (14 and 10) and proved unsuitable due to motion sensitivity and geometrical uncertainties. T1w MRI showed an intermediate number of LNs (17), provided valuable anatomical information, but lacked LN contrast.

CONCLUSION

Explicit LN imaging was achieved, in supine RT position, using MRI. Two T2w FSE techniques had the highest detection rates and were motion insensitive. T1w MRI showed anatomical information. MRI enables direct delineation of individual LNs.

ADVANCES IN KNOWLEDGE

Our optimized MRI scans enable accurate target definition in MRI-guided regional breast RT and development of personalized treatments.

Is diffusion-weighted MRI useful for differentiation of small non-necrotic cervical lymph nodes in patients with head and neck malignancies?

OBJECTIVE

To evaluate the usefulness of measuring the apparent diffusion coefficient (ADC) in diffusion-weighted magnetic resonance imaging to distinguish benign from small, non-necrotic metastatic cervical lymph nodes in patients with head and neck cancers.

MATERIALS AND METHODS

Twenty-six consecutive patients with head and neck cancer underwent diffusion-weighted imaging (b value, 0 and 800 s/mm(2)) preoperatively between January 2009 and December 2010. Two readers independently measured the ADC values of each cervical lymph node with a minimum-axial diameter of ≥ 5 mm but < 11 mm using manually drawn regions of interest. Necrotic lymph nodes were excluded. Mean ADC values were compared between benign and metastatic lymph nodes after correlating the pathology.

RESULTS

A total of 116 lymph nodes (91 benign and 25 metastatic) from 25 patients were included. Metastatic lymph nodes (mean ± standard deviation [SD], 7.4 ± 1.6 mm) were larger than benign lymph nodes (mean ± SD, 6.6 ± 1.4 mm) (p = 0.018). Mean ADC values for reader 1 were 1.17 ± 0.31 × 10(-3) mm(2)/s for benign and 1.25 ± 0.76 × 10(-3) mm(2)/s for metastatic lymph nodes. Mean ADC values for reader 2 were 1.21 ± 0.46 × 10(-3) mm(2)/s for benign and 1.14 ± 0.34 × 10(-3) mm(2)/s for metastatic lymph nodes. Mean ADC values between benign and metastatic lymph nodes were not significantly different (p = 0.594 for reader 1, 0.463 for reader 2).

CONCLUSION

Measuring mean ADC does not allow differentiating benign from metastatic cervical lymph nodes in patients with head and neck cancer and non-necrotic, small lymph nodes.

Enhancement of anatomical structures and detection of metastatic cervical lymph nodes: comparison of two different contrast material doses

PURPOSE

To determine if a 20 % reduction in the contrast material dose is acceptable in the CT evaluation of patients with head and neck malignancy.

MATERIALS AND METHODS

Sixty consecutive patients (mean age 67 years) with head and neck malignancy underwent contrast-enhanced CT according to two different protocols: protocol A (80 mL of contrast material administered at an injection rate of 1.5 mL/s) and protocol B (100 mL at 1.9 mL/s). The enhancement of anatomical structures and detectability of metastatic nodes were compared between the two protocols. Pathologic analysis of the surgical resection served as the reference standard.

RESULTS

CT numbers of the anatomical structures were not significantly different between the two protocols. Mean sensitivity (64 and 77 % for protocols A and B, respectively), specificity (78 and 84 %), and accuracy (74 and 83 %) tended to be higher for protocol B than for A, but no significant difference was found.

CONCLUSION

Reducing the contrast material dose by 20 % did not significantly impair the enhancement of anatomical structures or the detection of metastatic cervical lymph nodes. Radiologists should therefore consider reducing the contrast material dose used in head and neck CT.

Correlation of apparent diffusion coefficients measured by diffusion-weighted MR imaging and standardized uptake values from FDG PET/CT in metastatic neck lymph nodes of head and neck squamous cell carcinomas

Both diffusion-weighted magnetic resonance imaging and fluorodeoxyglucose positron emission tomography/computed tomography are oncological imaging techniques. The aim of this study was to assess any correlation between apparent diffusion coefficients and standardized uptake value in metastatic neck lymph nodes of head and neck squamous cell carcinomas.

Value of a Dixon-based MR/PET attenuation correction sequence for the localization and evaluation of PET-positive lesions

PURPOSE

In this study, the potential contribution of Dixon-based MR imaging with a rapid low-resolution breath-hold sequence, which is a technique used for MR-based attenuation correction (AC) for MR/positron emission tomography (PET), was evaluated for anatomical correlation of PET-positive lesions on a 3T clinical scanner compared to low-dose CT. This technique is also used in a recently installed fully integrated whole-body MR/PET system.

METHODS

Thirty-five patients routinely scheduled for oncological staging underwent (18)F-fluorodeoxyglucose (FDG) PET/CT and a 2-point Dixon 3-D volumetric interpolated breath-hold examination (VIBE) T1-weighted MR sequence on the same day. Two PET data sets reconstructed using attenuation maps from low-dose CT (PET(AC_CT)) or simulated MR-based segmentation (PET(AC_MR)) were evaluated for focal PET-positive lesions. The certainty for the correlation with anatomical structures was judged in the low-dose CT and Dixon-based MRI on a 4-point scale (0-3). In addition, the standardized uptake values (SUVs) for PET(AC_CT) and PET(AC_MR) were compared.

RESULTS

Statistically, no significant difference could be found concerning anatomical localization for all 81 PET-positive lesions in low-dose CT compared to Dixon-based MR (mean 2.51 ± 0.85 and 2.37 ± 0.87, respectively; p = 0.1909). CT tended to be superior for small lymph nodes, bone metastases and pulmonary nodules, while Dixon-based MR proved advantageous for soft tissue pathologies like head/neck tumours and liver metastases. For the PET(AC_CT)- and PET(AC_MR)-based SUVs (mean 6.36 ± 4.47 and 6.31 ± 4.52, respectively) a nearly complete concordance with a highly significant correlation was found (r = 0.9975, p < 0.0001).

CONCLUSION

Dixon-based MR imaging for MR AC allows for anatomical allocation of PET-positive lesions similar to low-dose CT in conventional PET/CT. Thus, this approach appears to be useful for future MR/PET for body regions not fully covered by diagnostic MRI due to potential time constraints.

Contrast-enhanced MR imaging of lymph nodes in cancer patients

The accurate identification and characterization of lymph nodes by modern imaging modalities has important therapeutic and prognostic significance for patients with newly diagnosed cancers. The presence of nodal metastases limits the therapeutic options, and it generally indicates a worse prognosis for the patients with nodal metastases. Yet anatomic imaging (CT and MR imaging) is of limited value for depicting small metastatic deposits in normal-sized nodes, and nodal size is a poor criterion when there is no extracapsular extension or focal nodal necrosis to rely on for diagnosing nodal metastases. Thus, there is a need for functional methods that can be reliably used to identify small metastases. Contrast-enhanced MR imaging of lymph nodes is a non-invasive method for the analysis of the lymphatic system after the interstitial or intravenous administration of contrast media. Moreover, some lymphotrophic contrast media have been developed and used for detecting lymph node metastases, and this detection is independent of the nodal size. This article will review the basic principles, the imaging protocols, the interpretation and the accuracies of contrast-enhanced MR imaging of lymph nodes in patients with malignancies, and we also focus on the recent issues cited in the literature. In addition, we discuss the results of several pre-clinical studies and animal studies that were conducted in our institution.

[Utility of PET-CT on radiotherapy planning of head and neck cancer. Our initial experience]

OBJECTIVE

To describe the methods used for the incorporation of FDG-PET-CT on radiotherapy planning of patients with head and neck cancer and also to evaluate the impact of FDG-PET-CT on staging and tumor volume definition.

MATERIAL AND METHODS

A prospective study in which 20 patients with head and neck tumor submitted for radiotherapy treatment were included. All underwent a whole body PET- CT (GE DSTE 16) for staging and restaging, also acquiring an additional 3h delayed PET image with diagnostic CT parameters for planning. A CT scan with diagnostic protocol, tabletop available for radiotherapy treatment and the same personalized head-shoulder mask were used in the latter. Lymph node involvement and/or distant involvement were evaluated, considering the changes in staging. We also evaluated the differences in volumes obtained between the different techniques. The threshold value used for delineating PET gross tumor volume (GTV) was empirically established and ranged from 20-40% of the maximum SUV.

RESULTS

Radiotherapy planning was performed with PET-CT in 20 patients between October 2007 to September 2008. A total of 29 lesions (18 primary lesions because 2 patients were excluded as no tumor was observed on the PET CT images, and 11 nodes). The most frequent location was oropharynx (5 patients). Mean maxSUV of the 29 lesions was 14.4 (range 5.0 and 26.4). No statistically significant differences were found between the GTV PET and GTV CT (mean 21.9cm³ and 19.3cm³, respectively). PET-CT modified the staging in 20% of the patients, with a diagnostic and therapeutic impact of 50 and 25%, respectively.

CONCLUSION

The incorporation of PET-CT in routine radiotherapy planning is a promising technique that requires close collaboration between the nuclear medicine and radiotherapy oncology departments. PET-CT achieves better staging in patients and has a significant diagnostic and therapeutic impact. The use of the hybrid technique avoids problems arising from co-registry as well as a second examination for planning with the consequent advantage for the patient. Nonetheless, more prospective and randomized studies with pathology specimens are needed to evaluate the real impact in the tumor volume definition.

Preoperative staging of papillary thyroid carcinoma: comparison of ultrasound imaging and CT

OBJECTIVE

The purpose of this study was to compare the diagnostic accuracy of ultrasound imaging with that of CT in the preoperative evaluation of primary tumors and cervical lymph nodes in patients with papillary thyroid carcinoma and to determine whether CT has greater diagnostic value than ultrasound alone in the care of these patients.

MATERIALS AND METHODS

The study population consisted of 299 consecutively registered patients with pathologically proven papillary thyroid carcinoma. The diagnostic accuracies of ultrasound, CT, and the combination of ultrasound and CT in the evaluation of primary tumors and lymph node metastasis were compared. We performed subgroup analysis to compare the findings on papillary thyroid microcarcinoma (10 mm in maximum diameter or smaller) with the findings on papillary thyroid carcinoma larger than 1 cm in maximum diameter.

RESULTS

Ultrasound was more accurate than CT in prediction of the presence of extrathyroidal tumor extension and of malignant disease in both thyroid lobes (p < 0.05) for overall lesions and for the two subgroups. In prediction of central node (neck level VI) metastasis, CT had greater sensitivity than ultrasound alone (p = 0.04) for overall lesions. Although the combination of ultrasound and CT had greater sensitivity than ultrasound alone in prediction of the presence of central node metastasis in the two subgroups, the sensitivity of the combination of ultrasound and CT did not reach statistical significance for papillary thyroid microcarcinoma. Ultrasound alone and ultrasound with CT had greater sensitivity than CT in prediction of lateral node (levels II-V) metastasis, but there was no significant difference in diagnostic value between ultrasound and the combination of ultrasound and CT for overall lesions or for the two subgroups (p > 0.05).

CONCLUSION

High-resolution ultrasound can be accurate in preoperative evaluation for extrathyroidal tumor extension and lateral lymph node metastasis. CT had greater sensitivity than ultrasound alone in the detection of central lymph node metastasis for all lesions. For papillary thyroid microcarcinoma, however, there was no significant difference in the diagnostic accuracy rates of ultrasound, CT, and the combination of ultrasound and CT.

[Neck dissection following chemoradiation for node positive head and neck carcinomas]

The optimal timing and extent of neck dissection in the context of chemoradiation for head and neck cancer remains controversial. For some institutions, it is uncertain whether neck dissection should still be performed upfront especially for cystic nodes. For others, neck dissection can be performed after chemoradiation and can be omitted for N1 disease as long as a complete response to chemoradiation is obtained. The question is debated for N2 and N3 disease even after a complete response as the correlation between radiological and clinical assessment and pathology may not be reliable. Response rates are greater than or equal to 60% and isolated neck failures are less than or equal to 10% with current chemoradiation protocols. Some therefore consider that systematic upfront or planned neck dissection would lead to greater than or equal to 50% unnecessary neck dissections for N2-N3 disease. Positron-emission tomography (PET) scanning to assess treatment response and have shown a very high negative predictive value of greater than or equal to 95% when using a standard uptake value of 3 for patients with a negative PET at four months after the completion of therapy. These data may support the practice of observing PET-negative necks. More evidence-based data are awaited to assess the need for neck dissection on PET. Selective neck dissection based on radiological assessment and peroperative findings and not exclusively on initial nodal stage may help to limit morbidity and to improve the quality of life without increasing the risk of neck failure. Adjuvant regional radiation boosts might be discussed on an individual basis for aggressive residual nodal disease with extracapsular spread and uncertain margins but evidence is missing. Medical treatments aiming at reducing the metastatic risk especially for N3 disease are to be evaluated.

Can FDG-PET assist in radiotherapy target volume definition of metastatic lymph nodes in head-and-neck cancer?

BACKGROUND AND PURPOSE

The role of FDG-PET in radiotherapy target volume definition of the neck was evaluated by comparing eight methods of FDG-PET segmentation to the current CT-based practice of lymph node assessment in head-and-neck cancer patients.

MATERIALS AND METHODS

Seventy-eight head-and-neck cancer patients underwent coregistered CT- and FDG-PET scans. Lymph nodes were classified as "enlarged" if the shortest axial diameter on CT was 10mm, and as "marginally enlarged" if it was 7-10mm. Subsequently, lymph nodes were assessed on FDG-PET applying eight segmentation methods: visual interpretation (PET(VIS)), applying fixed thresholds at a standardized uptake value (SUV) of 2.5 and at 40% and 50% of the maximum signal intensity of the primary tumor (PET(SUV), PET(40%), PET(50%)) and applying a variable threshold based on the signal-to-background ratio (PET(SBR)). Finally, PET(40%N), PET(50%N) and PET(SBRN) were acquired using the signal of the lymph node as the threshold reference.

RESULTS

Of 108 nodes classified as "enlarged" on CT, 75% were also identified by PET(VIS), 59% by PET(40%), 43% by PET(50%) and 43% by PET(SBR). Of 100 nodes classified as "marginally enlarged", only a minority were visualized by FDG-PET. The respective numbers were 26%, 10%, 7% and 8% for PET(VIS), PET(40%), PET(50%) and PET(SBR). PET(40%N), PET(50%N) and PET(SBRN), respectively, identified 66%, 82% and 96% of the PET(VIS)-positive nodes.

CONCLUSIONS

Many lymph nodes that are enlarged and considered metastatic by standard CT-based criteria appear to be negative on FDG-PET scan. Alternately, a small proportion of marginally enlarged nodes are positive on FDG-PET scan. However, the results are largely dependent on the PET segmentation tool used, and until proper validation FDG-PET is not recommended for target volume definition of metastatic lymph nodes in routine practice.

Head and neck squamous cell carcinoma: value of diffusion-weighted MR imaging for nodal staging

PURPOSE

To evaluate diffusion-weighted (DW) magnetic resonance (MR) imaging, as compared with turbo spin-echo MR imaging, for the detection of nodal metastases in head and neck squamous cell carcinoma (HNSCC).

MATERIALS AND METHODS

The study was approved by the ethics committee, and patients gave written informed consent. Before undergoing surgery, 33 consecutive patients underwent 1.5-T MR imaging, including DW imaging performed with a wide range of b values (0-1000 sec/mm(2)). The apparent diffusion coefficients (ADCs) of lymph nodes 4 mm or greater in short-axis diameter depicted on images obtained with b values of 0 and 1000 sec/mm(2) were calculated. After topographic correlation, the lymph nodes were evaluated microscopically with prekeratin immunostaining. The optimal ADC thresholds for discriminating between metastatic and benign lymph nodes were determined. The sensitivity, specificity, and accuracy of DW imaging were calculated separately-on per-lymph-node and per-neck-level bases-for all lymph nodes and for supracentimeter and subcentimeter lymph nodes and were compared with corresponding turbo spin-echo MR imaging values.

RESULTS

Correlation of histopathologic and radiologic findings was possible for 301 lymph nodes. The ADC derived from the signal intensity averaged across images obtained with b values of 0 and 1000 sec/mm(2) (ADC(b0-1000)) was 1.19 x 10(-3) mm(2)/sec +/- 0.22 (standard deviation) for benign lymph nodes and 0.85 x 10(-3) mm(2)/sec +/- 0.27 for malignant lymph nodes (P < .0001). With an optimal ADC(b0-1000) threshold of 0.94 x 10(-3) mm(2)/sec, 84% sensitivity, 94% specificity, and 91% accuracy for differentiation of malignant versus benign status of each lymph node and 94% sensitivity, 97% specificity, and 97% accuracy for differentiation at each neck level were achieved. Compared with turbo spin-echo imaging, DW imaging had higher sensitivity (76% vs 7%) but slightly lower specificity (94.0% vs 99.5%) for detection of subcentimeter nodal metastases.

CONCLUSION

DW imaging performed with ADC(b0-1000) values had higher accuracy than turbo spin-echo MR imaging in nodal staging, providing added value in the detection of subcentimeter nodal metastases.

[Cervical lymph nodes]

Imaging plays a chief role in the care and monitoring of patients in cervico-facial oncology. The radiologist must know the anatomy of different lymph nodes as well as signs of malignancy (hypertrophy, enhancement, necrosis, capsular rupture, etc.). CT is still the first-line examination because of its high reliability, its accessibility and its ability to make an assessment of the upper aero digestive ways at the same time. Ultrasound is very accuracy, and allows the realization of cytoponction, but does not provide a complete exploration of the neck. MRI does not appear to be indicated for the first intention, but the new rapid sequences (STIR, diffusion) seem interesting. The PET-CT is useful in post-therapeutic management of patients, and probably in the initial staging, but its accessibility is poor.

Squamous Cell Carcinoma: Initial Diagnosis and Staging with PET/CT

Squamous cell carcinoma is the most frequent malignancy of the head and neck region, accounting for 5% of all malignant tumors worldwide. Accurate staging at diagnosis is critical for selection of appropriate treatment strategy. A variety of therapeutic options are used for treatment, including surgery with or without radical dissection, lymph node dissections of various severities, radiotherapy, chemotherapy, and combinations of these. Precise prediction of the extent of primary tumors, detection of unknown primary tumor, cervical lymph node status, and distant metastatic spread is important for treatment planning and prognosis. Accurate evaluation of these factors prior to treatment helps guide surgical extent or radiation porta, minimizing locoregional treatment failure.