Advanced dual-energy CT applications for the evaluation of the soft tissues of the neck.

There are multiple emerging advanced computed tomography (CT) applications for the evaluation of the neck, many based on dual-energy CT (DECT). DECT is an advanced form of CT in which scan acquisition is performed at two different energies, enabling spectral tissue characterisation beyond what is possible with conventional single-energy CT and potentially providing a new horizon for quantitative analysis and tissue characterisation, particularly in oncological imaging. The purpose of this review is to familiarise the reader with DECT principles and review different clinical applications for the evaluation of the soft tissues of the neck. The article will begin with an overview of DECT scan acquisition, material characterisation, reconstructions, and basic considerations for implementation in the clinical setting. This will then be followed by a review of different clinical applications. The focus will be on oncological imaging, but artefact reduction and other miscellaneous applications will also be discussed.

Setting the Stage for 2018: How the Changes in the American Joint Committee on Cancer/Union for International Cancer Control Cancer Staging Manual Eighth Edition Impact Radiologists.

The updated eighth edition of the Cancer Staging Manual of the American Joint Committee on Cancer will be implemented in January 2018. There are multiple changes to the head and neck section of the manual, which will be relevant to radiologists participating in multidisciplinary head and neck tumor boards and reading pretreatment head and neck cancer scans. Human papillomavirus-related/p16(+) oropharyngeal squamous cell carcinoma will now be staged separately; this change reflects the markedly better prognosis of these tumors compared with non-human papillomavirus/p16(-) oropharyngeal squamous cell carcinoma. Nodal staging has dramatically changed so that there are different tables for human papillomavirus/p16(+) oropharyngeal squamous cell carcinoma, Epstein-Barr virus-related nasopharyngeal carcinoma, and all other head and neck squamous cell carcinomas. Extranodal extension of tumor is a new clinical feature for this third staging group. In the oral cavity, the pathologically determined depth of tumor invasion is a new staging criterion, while extrinsic tongue muscle invasion is no longer part of staging. This review serves to educate radiologists on the eighth edition changes and their rationale.

Revelations of an overt water contamination.

BACKGROUND: Contaminated water sources are major cause of water borne diseases of public health importance. Usually, contamination is suspected after an increase in patient load. METHODS: Two health teams investigated the episode. First team conducted sanitary survey, and second team undertook water safety and morbidity survey. On-site testing was carried out from source till consumer end. Investigation was also undertaken to identify factors which masked the situation. Prevention and control measures included super chlorination, provision of alternate drinking water sources, awareness campaign, layout of new water pipeline bypassing place of contamination, repair of sewers, flushing and cleaning of water pipelines, and repeated water sampling and testing. RESULTS: Multiple sources of drinking water supply were detected. Water samples from consumer end showed 18 coliforms per 100 ml. Sewer cross connection with active leakage in water pipeline was found and this was confirmed by earth excavation. Water safety and morbidity survey found majority of households receiving contaminated water supply. This survey found no significant difference among households receiving contaminated water supply and those receiving clean water. Average proportion of household members with episode of loose motions, pain abdomen, vomiting, fever, and eye conditions was significantly more among households receiving contaminated water. CONCLUSION: The present study documents detailed methodology of investigation and control measures to be instituted on receipt of contaminated water samples. Effective surveillance mechanisms for drinking water supplies such as routine testing of water samples can identify water contamination at an early stage and prevent an impending outbreak.

Feasibility analysis of the parametric response map as an early predictor of treatment efficacy in head and neck cancer.

BACKGROUND AND PURPOSE: Estimating changes in the volume transfer constant, normalized area under the contrast-enhancement time curve at 60 seconds, and fractional blood plasma volume by using dynamic contrast-enhanced MR imaging may be useful in predicting tumor response to chemoradiation. We hypothesized that the parametric response map, a voxel-by-voxel analysis of quantitative dynamic contrast-enhanced MR imaging maps, predicts survival in patients with head and neck cancer. MATERIALS AND METHODS: Ten patients with locoregionally advanced head and neck squamous cell carcinoma underwent definitive concurrent chemoradiation therapy. For each patient, dynamic contrast-enhanced MR imaging data were collected before and 2 weeks after treatment initiation. Change in perfusion parameters within the primary tumor volume with time was analyzed by parametric response mapping and by whole-tumor mean percentage change. Outcome was defined as overall survival. The perfusion parameter and metric most predictive of outcome were identified. Overall survival was estimated by the log-rank test and Kaplan-Meier survival curve. RESULTS: The volume transfer constant and normalized area under the contrast-enhancement time curve at 60 seconds were predictive of survival both in parametric response map analysis (volume transfer constant, P = .002; normalized area under the contrast-enhancement time curve at 60 seconds, P = .02) and in the percentage change analysis (volume transfer constant, P = .04; normalized area under the contrast-enhancement time curve at 60 seconds, P = .02). Blood plasma volume predicted survival in neither analysis. CONCLUSIONS: Parametric response mapping of MR perfusion biomarkers could potentially guide treatment modification in patients with predicted treatment failure. Larger studies are needed to determine whether parametric response map analysis or percentage signal change in these perfusion parameters is the stronger predictor of survival.

Raise the bar and lower the dose: current and future strategies for radiation dose reduction in head and neck imaging.

SUMMARY: Technologic advances in CT have generated a dramatic increase in the number of CT studies, with a resultant increase in the radiation dose related to CT scanning. Such increase in radiation dose is becoming a concern for the radiology community, especially with increasing public awareness of the dose burden related to examinations. To cope with the increase in CT-related radiation exposure, it is becoming necessary to optimize CT imaging protocols and apply radiation dose reduction techniques to ensure the best imaging with the lowest radiation dose.

CT perfusion can predict overexpression of CXCL8 (interleukin-8) in head and neck squamous cell carcinoma.

BACKGROUND AND PURPOSE: Increased angiogenesis in head and neck squamous cell carcinoma correlates to more aggressive tumors with increased morbidity. Because both elevated blood flow and high serum CXCL8 levels are correlated with increased angiogenesis, our objective was to see if elevated blood flow measured with CT perfusion correlated with CXCL8 levels, thereby helping to identify candidates for targeted therapies that inhibit the Bcl-2 proangiogenic pathway associated with CXCL8. MATERIALS AND METHODS: Seven patients with locally recurrent or metastatic head and neck squamous cell carcinoma were enrolled in the trial. These patients underwent CT perfusion and the following parameters were measured: blood volume, blood flow, capillary permeability, and MTT; relative values were calculated by dividing by normal-appearing muscle. Serum was drawn for CXCL8 enzyme-linked immunosorbent assay analysis in these patients. RESULTS: There was a significant positive correlation between the CXCL8 levels and relative blood flow (r = 0.94; P = .01). No correlation was found between CXCL8 and relative blood volume, relative capillary permeability, or relative MTT. CONCLUSIONS: Relative blood flow may be useful as a surrogate marker for elevated CXCL8 in patients with head and neck squamous cell cancer. Patients with elevated relative blood flow may benefit from treatment targeting the Bcl-2 proangiogenic pathways.

Human papillomavirus, p16, and epidermal growth factor receptor biomarkers and CT perfusion values in head and neck squamous cell carcinoma.

BACKGROUND AND PURPOSE: Head and neck squamous cell carcinoma tumors positive for laboratory biomarkers hrHPV and p16 and negative for EGFR often respond better to nonsurgical organ-preservation therapy than hrHPV-negative, p16-negative, and EGFR overexpressing tumors. CTP has been shown to distinguish which locally advanced head and neck squamous cell carcinomas will respond to induction chemotherapy or chemoradiation. Our purpose was to determine whether a relationship exists between CTP measures and the expression of these laboratory biomarkers, because both appear to separate head and neck squamous cell carcinoma tumors into similar groups. MATERIALS AND METHODS: We conducted an institutional review board-approved, Health Insurance Portability and Accountability Act-compliant retrospective review of head and neck CTP in 25 patients with locally advanced head and neck squamous cell carcinoma who had signed informed consent. Eight women and 17 men, 41-80 years of age, constituted a pretreatment group of 18 patients and a palliative group of 7 patients. Tumor biopsy samples were analyzed for overexpression of hrHPV, p16, and EGFR. The hrHPV, p16, and EGFR status of the tumors was correlated with CTP parameters (MTT, BV, BF, CP) by using the Wilcoxon evaluation and Fischer exact test. RESULTS: There were significantly lower CP values in pretreatment tumors overexpressing EGFR (P = .04). CP values ≤17.23 were significantly correlated with EGFR overexpression (P = .015). A trend toward higher CP values was present in hrHPV-positive and p16-overexpressing pretreatment tumors (P = .14). CONCLUSIONS: A significant correlation exists between CTP measures and EGFR overexpression in head and neck squamous cell carcinomas, suggesting an association between certain imaging findings and molecular biomarkers. These results may be related to a tumor cell survival mechanism linking perfusion and biomarker expression.

Biologic imaging of head and neck cancer: the present and the future.

While anatomic imaging (CT and MR imaging) of HNC is focused on diagnosing and/or characterizing the disease, defining its local extent, and evaluating distant spread, accurate assessment of the biologic status of the cancer (cellularity, growth rate, response to nonsurgical chemoradiation therapy, and so forth) can be invaluable for prognostication, planning therapy, and follow-up of lesions after therapy. The combination of anatomic and biologic imaging techniques can thus provide a more comprehensive evaluation of the patient. The purpose of this work was to review the present and future clinical applications of advanced biologic imaging techniques in HNC evaluation and management. As part of the biologic imaging array, we discuss MR spectroscopy, diffusion and perfusion MR imaging, CTP, and FDG-PET scanning and conclude with exciting developments that hold promise in assessment of tumor hypoxia and neoangiogenesis.

Correlation of radiographic and pathologic findings of dermal lymphatic invasion in head and neck squamous cell carcinoma.

HNSCC that involves the skin is able to invade the dermal lymphatic system. Currently there is no way to identify patients with dermal lymphatic invasion preoperatively. The purpose of this study is to determine whether CT can predict dermal lymphatic invasion. Medical records, CT scans, and corresponding histopathologic slides were reviewed of HNSCC patients with skin resected as part of their treatment. Dermal lymphatic invasion was defined radiographically as linear reticulations of the dermis and subcutaneous fat adjacent to the tumor. Twelve patients were identified with imaging suggestive of dermal lymphatic invasion. The corresponding pathology slides showed only 1 of the 12 patients had dermal lymphatic invasion, whereas the other 11 specimens showed peritumoral inflammation without evidence of tumor invasion. This study demonstrates that the linear areas of reticulation are most commonly caused by peritumoral inflammation and are not due to dermal lymphatic invasion.

Trastuzumab (herceptin).

Herceptin (trastuzumab) is a human monoclonal antibody that interferes with the HER2 receptor. It is currently the only FDA-approved therapeutic antibody for HER2-positive breast cancer. This article will present the mechanism at action as well as the clinical role at this monoclonal antibody.

Panitumumab (vectibix).

Panitumumab (Vectibix), is a human monoclonal antibody EGFR antagonist indicated as a single agent for the treatment of metastatic colorectal carcinoma with disease progression on or following fluoropyrimidine, oxaliplatin, and irinotecan chemotherapy regimens. This article will present the mechanism of action as well as the clinical role for this monoclonal antibody.

Tositumomab and iodine I 131 tositumomab (Bexaar).

Tositumomab and iodine I 131 tositumomab (Bexaar) therapeutic regimen targets monoclonal antibodies against the CD20 antigen expressed in non-Hodgkin lymphoma. This article reviews the mechanism of action and clinical indications for this regimen.

Characterization and proinflammatory response of airborne biological particles from wastewater treatment plants.

Wastewater contains a variety of microorganisms, and unit operations in the plants could release these biological components into the air environment. These airborne biological particles could have adverse health effects on plant workers and the downwind population. This study provides a first report on the concentration and characterization of the airborne biological particles in six wastewater treatment plants in Mumbai, India. The study indicates that 49% and 27% of the samples exceed, respectively, the exposure limit for airborne endotoxin and bacteria in occupational settings. Endotoxin was identified as the single most important component of the particulate matter responsible for induction of proinflammatory indicator (tumor necrosis factor-α) in in vitro assay. Identification of several clinically important bacterial species in the samples suggests that the workers at the treatment plant are exposed to opportunistic and infectious bacteria. Principal component analysis was used to identify the groups among the bacterial species which serves as the signature for transport study. Analysis also shows that the component related to spore-forming bacteria is present in all samples.

Treatment response assessment of head and neck cancers on CT using computerized volume analysis.

BACKGROUND AND PURPOSE: Head and neck cancer can cause substantial morbidity and mortality. Our aim was to evaluate the potential usefulness of a computerized system for segmenting lesions in head and neck CT scans and for estimation of volume change of head and neck malignant tumors in response to treatment. MATERIALS AND METHODS: CT scans from a pretreatment examination and a post 1-cycle chemotherapy examination of 34 patients with 34 head and neck primary-site cancers were collected. The computerized system was developed in our laboratory. It performs 3D segmentation on the basis of a level-set model and uses as input an approximate bounding box for the lesion of interest. The 34 tumors included tongue, tonsil, vallecula, supraglottic, epiglottic, and hard palate carcinomas. As a reference standard, 1 radiologist outlined full 3D contours for each of the 34 primary tumors for both the pre- and posttreatment scans and a second radiologist verified the contours. RESULTS: The correlation between the automatic and manual estimates for both the pre- to post-treatment volume change and the percentage volume change for the 34 primary-site tumors was 0.95, with an average error of -2.4 ± 8.5% by automatic segmentation. There was no substantial difference and specific trend in the automatic segmentation accuracy for the different types of primary head and neck tumors, indicating that the computerized segmentation performs relatively robustly for this application. CONCLUSIONS: The tumor size change in response to treatment can be accurately estimated by the computerized segmentation system relative to radiologists' manual estimations for different types of head and neck tumors.

Temozolomide (Temodar).

Temozolomide, an oral alkylating agent, is a commonly used medicine in the treatment of anaplastic astrocytoma and glioblastoma multiforme. This paper will present the mechanism of action as well as the clinical role for this chemotherapeutic drug.

Rituximab (Rituxan).

Rituximab is a monoclonal antibody that was first approved by the FDA as an antineoplastic agent designed to treat B-cell malignancies. This article will review the mechanism of action and clinical role of this anti-B-cell agent.

Cetuximab (erbitux).

Cetuximab, a recombinant chimeric monoclonal antibody, has been successfully used in the treatment of the head and neck and colorectal cancers. We present a review of its mechanism of action, indications, side effects and economic issues, accompanied by a clinical example from our institution.

Bevacizumab (Avastin).

Bevacizumab is a humanized monoclonal antibody that was the first FDA approved therapy designed to inhibit angiogenesis. This paper will review the mechanism of action and clinical role of this antiangiogenic agent.

Utility of the k-means clustering algorithm in differentiating apparent diffusion coefficient values of benign and malignant neck pathologies.

BACKGROUND AND PURPOSE: Does the K-means algorithm do a better job of differentiating benign and malignant neck pathologies compared to only mean ADC? The objective of our study was to analyze the differences between ADC partitions to evaluate whether the K-means technique can be of additional benefit to whole-lesion mean ADC alone in distinguishing benign and malignant neck pathologies. MATERIAL AND METHODS: MR imaging studies of 10 benign and 10 malignant proved neck pathologies were postprocessed on a PC by using in-house software developed in Matlab. Two neuroradiologists manually contoured the lesions, with the ADC values within each lesion clustered into 2 (low, ADC-ADC(L); high, ADC-ADC(H)) and 3 partitions (ADC(L); intermediate, ADC-ADC(I); ADC(H)) by using the K-means clustering algorithm. An unpaired 2-tailed Student t test was performed for all metrics to determine statistical differences in the means of the benign and malignant pathologies. RESULTS: A statistically significant difference between the mean ADC(L) clusters in benign and malignant pathologies was seen in the 3-cluster models of both readers (P = .03 and .022, respectively) and the 2-cluster model of reader 2 (P = .04), with the other metrics (ADC(H), ADC(I); whole-lesion mean ADC) not revealing any significant differences. ROC curves demonstrated the quantitative differences in mean ADC(H) and ADC(L) in both the 2- and 3-cluster models to be predictive of malignancy (2 clusters: P = .008, area under curve = 0.850; 3 clusters: P = .01, area under curve = 0.825). CONCLUSIONS: The K-means clustering algorithm that generates partitions of large datasets may provide a better characterization of neck pathologies and may be of additional benefit in distinguishing benign and malignant neck pathologies compared with whole-lesion mean ADC alone.