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  Quantitative BOLD (qBOLD) imaging of oxygen metabolism and blood oxygenation in the human body: A scoping review

  Panek, Rafal (2024)

  Purpose: There are many approaches to the quantitative BOLD (qBOLD) technique described in the literature, differing in pulse sequences, MRI parameters and data processing. Thus, in this review, we summarized the acquisition methods, approaches used for oxygenation quantification and clinical populations investigated. Method(s): Three databases were systematically searched (Medline, Embase, and Web of Science) for published research that used qBOLD methods for quantification of oxygen metabolism. Data extraction and synthesis were performed by one author and reviewed by a second author. Result(s): A total of 93 relevant papers were identified. Acquisition strategies were summarized, and oxygenation parameters were found to have been investigated in many pathologies such as steno-occlusive diseases, stroke, glioma, and multiple sclerosis disease. Conclusion(s): A summary of qBOLD approaches for oxygenation measurements and applications could help researchers to identify good practice and provide objective information to inform the development of future consensus recommendations.Copyright © 2024 The Author(s). Magnetic Resonance in Medicine published by Wiley Periodicals LLC on behalf of International Society for Magnetic Resonance in Medicine.
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  Oxygen-enhanced MRI assessment of tumour hypoxia in head and neck cancer is feasible and well tolerated in the clinical setting

  McCabe, Alastair; Rowe, Selena; Shah, Jagrit; Morgan, Paul S.; Panek, Rafal (2024)

  Background: Tumour hypoxia is a recognised cause of radiotherapy treatment resistance in head and neck squamous cell carcinoma (HNSCC). Current positron emission tomography-based hypoxia imaging techniques are not routinely available in many centres. We investigated if an alternative technique called oxygen-enhanced magnetic resonance imaging (OE-MRI) could be performed in HNSCC. Method(s): A volumetric OE-MRI protocol for dynamic T1 relaxation time mapping was implemented on 1.5-T clinical scanners. Participants were scanned breathing room air and during high-flow oxygen administration. Oxygen-induced changes in T1 times (DELTAT1) and R2* rates (DELTAR2*) were measured in malignant tissue and healthy organs. Unequal variance t-test was used. Patients were surveyed on their experience of the OE-MRI protocol. Result(s): Fifteen patients with HNSCC (median age 59 years, range 38 to 76) and 10 non-HNSCC subjects (median age 46.5 years, range 32 to 62) were scanned; the OE-MRI acquisition took less than 10 min and was well tolerated. Fifteen histologically confirmed primary tumours and 41 malignant nodal masses were identified. Median (range) of DELTAT1 times and hypoxic fraction estimates for primary tumours were -3.5% (-7.0 to -0.3%) and 30.7% (6.5 to 78.6%) respectively. Radiotherapy-responsive and radiotherapy-resistant primary tumours had mean estimated hypoxic fractions of 36.8% (95% confidence interval CI] 17.4 to 56.2%) and 59.0% (95% CI 44.6 to 73.3%), respectively (p = 0.111). Conclusion(s): We present a well-tolerated implementation of dynamic, volumetric OE-MRI of the head and neck region allowing discernment of differing oxygen responses within biopsy-confirmed HNSCC. Trial registration: ClinicalTrials.gov, NCT04724096. Registered on 26 January 2021. Relevance statement: MRI of tumour hypoxia in head and neck cancer using routine clinical equipment is feasible and well tolerated and allows estimates of tumour hypoxic fractions in less than ten minutes. Key points: * Oxygen-enhanced MRI (OE-MRI) can estimate tumour hypoxic fractions in ten-minute scanning. * OE-MRI may be incorporable into routine clinical tumour imaging. * OE-MRI has the potential to predict outcomes after radiotherapy treatment. Graphical Abstract: (Figure presented.)Copyright © The Author(s) 2024.
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  T1 based oxygen-enhanced MRI in tumours; A scoping review of current research

  McCabe, Alastair; Shah, Jagrit; Morgan, Paul S.; Panek, Rafal (2023)

  OBJECTIVE: Oxygen-enhanced MRI (OE-MRI) or tissue oxygen-level dependent (TOLD) MRI is an imaging technique under investigation for its ability to quantify and map oxygen distributions within tumours. The aim of this study was to identify and characterise the research into OE-MRI for characterising hypoxia in solid tumours., METHODS: A scoping review of published literature was performed on the PubMed and Web of Science databases for articles published before 27 May 2022. Studies imaging solid tumours using proton-MRI to measure oxygen-induced T1/R1 relaxation time/rate changes were included. Grey literature was searched from conference abstracts and active clinical trials., RESULTS: 49 unique records met the inclusion criteria consisting of 34 journal articles and 15 conference abstracts. The majority of articles were pre-clinical studies (31 articles) with 15 human only studies. Pre-clinical studies in a range of tumour types demonstrated consistent correlation of OE-MRI with alternative hypoxia measurements. No clear consensus on optimal acquisition technique or analysis methodology was found. No prospective, adequately powered, multicentre clinical studies relating OE-MRI hypoxia markers to patient outcomes were identified., CONCLUSION: There is good pre-clinical evidence of the utility of OE-MRI in tumour hypoxia assessment; however, there are significant gaps in clinical research that need to be addressed to develop OE-MRI into a clinically applicable tumour hypoxia imaging technique., ADVANCES IN KNOWLEDGE: The evidence base of OE-MRI in tumour hypoxia assessment is presented along with a summary of the research gaps to be addressed to transform OE-MRI derived parameters into tumour hypoxia biomarkers.
• Readmission following hospital admission for community-acquired pneumonia in England

  Lawrence, Hannah; Lim, Wei Shen (2023)

  INTRODUCTION: Readmission rates following hospital admission with community-acquired pneumonia (CAP) have increased in the UK over the past decade. The aim of this work was to describe the cohort of patients with emergency 30-day readmission following hospitalisation for CAP in England and explore the reasons for this., METHODS: A retrospective analysis of cases from the British Thoracic Society national adult CAP audit admitted to hospitals in England with CAP between 1 December 2018 and 31 January 2019 was performed. Cases were linked with corresponding patient level data from Hospital Episode statistics, providing data on the primary diagnosis treated during readmission and mortality. Analyses were performed describing the cohort of patients readmitted within 30 days, reasons for readmission and comparing those readmitted and primarily treated for pneumonia with other diagnoses., RESULTS: Of 8136 cases who survived an index admission with CAP, 1304 (15.7%) were readmitted as an emergency within 30 days of discharge. The main problems treated on readmission were pneumonia in 516 (39.6%) patients and other respiratory disorders in 284 (21.8%). Readmission with pneumonia compared with all other diagnoses was associated with significant inpatient mortality (15.9% vs 6.5%; aOR 2.76, 95% CI 1.86 to 4.09, p: Of 8136 cases who survived an index admission with CAP, 1304 (15.7%) were readmitted as an emergency within 30 days of discharge. The main problems treated on readmission were pneumonia in 516 (39.6%) patients and other respiratory disorders in 284 (21.8%). Readmission with pneumonia compared with all other diagnoses was associated with significant inpatient mortality (15.9% vs 6.5%; aOR 2.76, 95% CI 1.86 to 4.09, p: Of 8136 cases who survived an index admission with CAP, 1304 (15.7%) were readmitted as an emergency within 30 days of discharge. The main problems treated on readmission were pneumonia in 516 (39.6%) patients and other respiratory disorders in 284 (21.8%). Readmission with pneumonia compared with all other diagnoses was associated with significant inpatient mortality (15.9% vs 6.5%; aOR 2.76, 95% CI 1.86 to 4.09, pCONCLUSION: Pneumonia is the most common condition treated on readmission following hospitalisation with CAP and carries a higher mortality than both the index admission or readmission due to other diagnoses. Strategies to reduce readmissions due to pneumonia are required. Copyright © Author(s) (or their employer(s)) 2023.
• Pneumococcal serotype trends, surveillance and risk factors in UK adult pneumonia, 2013-18

  Pick, Harry J.; Rodrigo, Chamira; Ashton, Deborah; Lawrence, Hannah; Baskaran, Vadsala; Lim, Wei Shen (2020)

  BACKGROUND: Changes over the last 5 years (2013-18) in the serotypes implicated in adult pneumococcal pneumonia and the patient groups associated with vaccine-type disease are largely unknown., METHODS: We conducted a population-based prospective cohort study of adults admitted to two large university hospitals with community-acquired pneumonia (CAP) between September 2013 and August 2018. Pneumococcal serotypes were identified using a novel 24-valent urinary monoclonal antibody assay and from blood cultures. Trends in incidence rates were compared against national invasive pneumococcal disease (IPD) data. Persons at risk of vaccine-type pneumonia (pneumococcal conjugate vaccine (PCV)13 and pneumococcal polysaccharide vaccine (PPV)23) were determined from multivariate analyses., FINDINGS: Of 2934 adults hospitalised with CAP, 1075 (36.6%) had pneumococcal pneumonia. The annual incidence of pneumococcal pneumonia increased from 32.2 to 48.2 per 100 000 population (2013-18), predominantly due to increases in PCV13non7-serotype and non-vaccine type (NVT)-serotype pneumonia (annual incidence rate ratio 1.12, 95% CI 1.04 to 1.21 and 1.19, 95% CI 1.10 to 1.28, respectively). Incidence trends were broadly similar to IPD data. PCV13non7 (56.9% serotype 3) and PPV23non13 (44.1% serotype 8) serotypes were identified in 349 (32.5%) and 431 (40.1%) patients with pneumococcal pneumonia, respectively. PCV13-serotype pneumonia (dominated by serotype 3) was more likely in patients in the UK pneumococcal vaccination clinical risk group (adjusted OR (aOR) 1.73, 95% CI 1.31 to 2.28) while PPV23-serotype pneumonia was more likely in patients outside the clinical risk group (aOR 1.54, 95% CI 1.13 to 2.10)., INTERPRETATION: The incidence of pneumococcal CAP is increasing, predominantly due to NVT serotypes and serotype 3. PPV23-serotype pneumonia is more likely in adults outside currently identified clinical risk groups. Copyright © Author(s) (or their employer(s)) 2020.

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