Cohort-based T-SSIM Visual Computing for Radiation Therapy Prediction and Exploration

We describe a visual computing approach to radiation therapy (RT) planning, based on spatial similarity within a patient cohort. In radiotherapy for head and neck cancer treatment, dosage to organs at risk surrounding a tumor is a large cause of treatment toxicity. Along with the availability of patient repositories, this situation has lead to clinician interest in understanding and predicting RT outcomes based on previously treated similar patients. To enable this type of analysis, we introduce a novel topology-based spatial similarity measure, T-SSIM, and a predictive algorithm based on this similarity measure. We couple the algorithm with a visual steering interface that intertwines visual encodings for the spatial data and statistical results, including a novel parallel-marker encoding that is spatially aware. We report quantitative results on a cohort of 165 patients, as well as a qualitative evaluation with domain experts in radiation oncology, data management, biostatistics, and medical imaging, who are collaborating remotely.Comment: IEEE VIS (SciVis) 201

Improving feedback of surveillance data on antimicrobial consumption, resistance and stewardship in England: putting the data at your Fingertips.

The provision of better access to and use of surveillance data is a key component of the UK 5 Year Antimicrobial Resistance (AMR) Strategy Since April 2016, PHE has made data on practice (infection prevention and control; antimicrobial stewardship) and outcome (prevalence of AMR, antibiotic use and healthcare-associated infections) available through Fingertips, a publicly accessible web tool (https://fingertips.phe.org.uk/profile/amr-local-indicators). Fingertips provides access to a wide range of public health data presented as thematic profiles, with the above data being available through the 'AMR local indicators' profile. Local data on a range of indicators can be viewed at the level of National Health Service acute trusts, Clinical Commissioning Groups or general practitioner practices, all of which can be compared with the corresponding aggregate values for England to allow benchmarking. The data can be viewed in a range of formats including an overview showing counts and rates, interactive maps, spine charts and graphs that show temporal trends over a range of time scales or allow correlations between pairs of indicators. The aim of the AMR local indicators profile on Fingertips is to support the development of local action plans to optimize antibiotic prescribing and reduce AMR and healthcare-associated infections. Provision of access to relevant information in an easy to use format will help local stakeholders, including healthcare staff, commissioners, Directors of Public Health, academics and the public, to benchmark relevant local AMR data and to monitor the impact of local initiatives to tackle AMR over time

Longitudinal characterization of the tumoral microbiome during radiotherapy in HPV-associated oropharynx cancer

Purpose: To describe the baseline and serial tumor microbiome in HPV-associated oropharynx cancer (OPC) over the course of radiotherapy (RT). Methods: Patients with newly diagnosed HPV-associated OPC treated with definitive radiotherapy +/- concurrent chemotherapy were enrolled in this prospective study. Using 16S rRNA gene sequencing, dynamic changes in the tumor site microbiome during RT were investigated. Surface tumor samples were obtained before RT and at week 1, 3 and 5 of RT. Radiological primary tumor response at mid-treatment was categorized as complete (CR) or partial (PR). Results: Ten patients were enrolled, but 9 patients were included in the final analysis. Mean age was 62 years (range: 51-71). As per AJCC 8th Ed, 56%, 22% and 22% of patients had stage I, II and III, respectively. At 4-weeks, 6 patients had CR and 3 patients had PR; at follow-up imaging post treatment, all patients had CR. The baseline diversity of the tumoral versus buccal microbiome was not statistically different. For the entire cohort, alpha diversity was significantly decreased over the course of treatment (p = 0.04). There was a significant alteration in the bacterial community within the first week of radiation. Baseline tumor alpha diversity of patients with CR was significantly higher than those with PR (p = 0.03). While patients with CR had significant reduction in diversity over the course of radiation (p = 0.01), the diversity remained unchanged in patients with PR. Patients with history of smoking had significantly increased abundance of  Kingella (0.05) and lower abundance of Stomatobaculum (p = 0.03) compared to never smokers. Conclusions: The tumor microbiome of HPV-associated OPC exhibits reduced alpha diversity and altered taxa abundance over the course of radiotherapy. The baseline bacterial profiles of smokers vs. non-smokers were inherently different. Baseline tumor alpha diversity of patients with CR was higher than patients with PR, suggesting that the microbiome deserves further investigation as a biomarker of radiation response

Simultaneously spatial and temporal Higher-Order Total Variations for noise suppression and motion reduction in DCE and IVIM.

In many applications based on kinetic evaluation analysis and model fitting, quantitative mapping retrieved on data series from modalites such as MRI is completed on a voxel-by-voxel basis, where motion and low signal to noise ratio (SNR) would considerably degenerate the reliability of estimations. The coherence of image series in space and time can be used as prior knowledge to mitigate this occurrence. In this study, spatial and temporal higher-order total variations (HOTVs) are applied on a data series of MRI signal (e.g. dynamic contrast-enhanced (DCE) MRI and intravoxel incoherent motion (IVIM) MRI) to exploit the coherence of signal in space and time to minimize the variabilities caused by motion as well as improving quality of images with low SNR while retaining the physical details of original data properly. Simultaneously applying spatial and temporal HOTVs on images is non-trivial in implementation since it is a non-smooth optimization problem with multiple regularizers. Therefore, we use the proximal gradient method as well as a primal-dual split proximal mechanism to address the problem properly. In addition to increase the reliability of quantitative parametric map estimations, this preprocessing procedure can be included into many existing map estimation algorithms and pipelines effortlessly. We demonstrate our method on the parametric maps estimation for DCE MRI and IVIM MRI

Original Lymphopenia during radiotherapy in patients with oropharyngeal cancer

PURPOSE/OBJECTIVE: Radiation-induced lymphopenia has been associated with poor survival outcomes in certain solid tumors such as esophageal, lung, cervical and pancreatic cancers. We aim to determine the effect of treatment-related lymphopenia during radiotherapy on outcomes of patients with oropharyngeal cancer. MATERIALS/METHODS: A retrospective analysis of all patients who completed definitive radiotherapy for oropharyngeal cancer at The University of Texas MD Anderson Cancer Center and had blood counts taken during radiotherapy from 2002 to 2013 were included. Patient, tumor and treatment characteristics, clinical outcomes and lymphocyte counts during radiotherapy were recorded. Lymphopenia was graded according to the CTCAE v4.0. Survival rates were estimated using the Kaplan-Meier method and compared with log-rank tests. RESULTS: 850 patients were evaluated. The median age was 57 years. The majority of the cohort had p16/HPV-positive disease (71%), 8% had HPV-negative disease and 21% were unknown. The median radiation total dose was 70 Gy. 45% of patients had induction chemotherapy, and 87% had concurrent chemotherapy. 703 (83%) patients developed ≥grade 3 (G3) lymphopenia and 209 (25%) had grade 4 (G4) lymphopenia during radiotherapy. The median follow-up was 59 months; the 5-year overall survival rate was 81%. There were no significant differences in overall survival rates nor in disease control rates, in those who developed G3/G4 lymphopenia compared with those who did not. No significant effect of lymphopenia on survival was observed when analyzed according to p16/HPV status. CONCLUSION: In this large cohort of patients with oropharyngeal cancer, the development of lymphopenia during radiotherapy did not impact outcomes

Comparison of tumor delineation using dual energy computed tomography versus magnetic resonance imaging in head and neck cancer re-irradiation cases.

In treatment planning, multiple imaging modalities can be employed to improve the accuracy of tumor delineation but this can be costly. This study aimed to compare the interobserver consistency of using dual energy computed tomography (DECT) versus magnetic resonance imaging (MRI) for delineating tumors in the head and neck cancer (HNC) re-irradiation scenario. Twenty-three patients with recurrent HNC and had planning DECT and MRI were identified. Contoured tumor volumes by seven radiation oncologists were compared. Overall, T1c MRI performed the best with median DSC of 0.58 (0-0.91) for T1c. T1c MRI provided higher interobserver agreement for skull base sites and 60 kV DECT provided higher interobserver agreement for non-skull base sites

18FDG positron emission tomography mining for metabolic imaging biomarkers of radiation-induced xerostomia in patients with oropharyngeal cancer

Purpose: Head and neck cancers radiotherapy (RT) is associated with inevitable injury to parotid glands and subsequent xerostomia. We investigated the utility of SUV derived from 18FDG-PET to develop metabolic imaging biomarkers (MIBs) of RT-related parotid injury. Methods: Data for oropharyngeal cancer (OPC) patients treated with RT at our institution between 2005 and 2015 with available planning computed tomography (CT), dose grid, pre- &amp; first post-RT 18FDG-PET-CT scans, and physician-reported xerostomia assessment at 3–6 months post-RT (Xero 3–6 ms) per CTCAE, was retrieved, following an IRB approval. A CT-CT deformable image co-registration followed by voxel-by-voxel resampling of pre &amp; post-RT 18FDG activity and dose grid were performed. Ipsilateral (Ipsi) and contralateral (contra) parotid glands were sub-segmented based on the received dose in 5 Gy increments, i.e. 0–5 Gy, 5–10 Gy sub-volumes, etc. Median and dose-weighted SUV were extracted from whole parotid volumes and sub-volumes on pre- &amp; post-RT PET scans, using in-house code that runs on MATLAB. Wilcoxon signed-rank and Kruskal-Wallis tests were used to test differences pre- and post-RT. Results: 432 parotid glands, belonging to 108 OPC patients treated with RT, were sub-segmented &amp; analyzed. Xero 3–6 ms was reported as: non-severe (78.7%) and severe (21.3%). SUV- median values were significantly reduced post-RT, irrespective of laterality (p = 0.02). A similar pattern was observed in parotid sub-volumes, especially ipsi parotid gland sub-volumes receiving doses 10–50 Gy (p < 0.05). Kruskal-Wallis test showed a significantly higher mean RT dose in the contra parotid in the patients with more severe Xero 3-6mo (p = 0.03). Multiple logistic regression showed a combined clinical-dosimetric-metabolic imaging model could predict the severity of Xero 3-6mo; AUC = 0.78 (95%CI: 0.66–0.85; p < 0.0001). Conclusion: We sought to quantify pre- and post-RT 18FDG-PET metrics of parotid glands in patients with OPC. Temporal dynamics of PET-derived metrics can potentially serve as MIBs of RT-related xerostomia in concert with clinical and dosimetric variables