F V Gleeson

Oxford University Hospitals NHS Trust, Oxford, England, United Kingdom

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Publications (112)646.87 Total impact

  • No preview · Article · Sep 2015 · European Respiratory Journal
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    ABSTRACT: Q.Clear, a Bayesian penalized likelihood reconstruction algorithm for PET, was recently introduced by GE Healthcare on their PET scanners to improve clinical image quality and quantification. In this work, we determined the optimum penalization factor (beta) for clinical use of Q.Clear and compared Q.Clear to standard PET reconstructions. A NEMA image quality phantom was scanned on a GE Discovery 690 ToF PET/CT and reconstructed using ordered subset expectation maximization (OSEM), OSEM with point spread function (PSF) modelling, and the Q.Clear algorithm (which also includes PSF modelling). Q.Clear was investigated for beta (B) values 100-1000. Contrast recovery (CR) and background variability (BV) were measured from three repeat scans, reconstructed with the different algorithms. Fifteen oncology body (18)F-FDG PET/CT scans were reconstructed using OSEM, OSEM PSF, and Q.Clear using B values of 200, 300, 400 and 500. These were visually analyzed by two scorers and scored by rank against a panel of parameters (overall image quality (IQ), background liver, mediastinum and marrow IQ, noise level, and lesion detectability). As beta is increased the CR and BV decreases, Q.Clear generally gives a higher CR and lower BV than OSEM. For the smallest sphere reconstructed with Q.Clear B400, CR is 28.4% and BV 4.2%, with corresponding values for OSEM 24.7%, 5.0%. For the largest hot sphere, Q.Clear B400 yields a CR of 75.2% and a BV of 3.8% with corresponding values for OSEM 64.4%, 4.0%. Scorer 1 and 2 ranked B400 as the preferred reconstruction in 13/15 (87%) and 10/15 (73%) cases. The least preferred reconstruction was OSEM PSF in all cases. In majority of cases, lesion detectability was highest ranked for B200, in 9/15 (67%) and 10/15 (73%), with OSEM PSF ranked lowest. Poor lesion detectability on OSEM PSF was seen in cases of mildly (18)F-FDG-avid mediastinal nodes in lung cancer and small liver metastases due to background noise. Conversely, OSEM PSF was ranked second highest for lesion detectability in majority of pulmonary nodule evaluation cases. The combined scores confirmed B400 to be the preferred reconstruction. Our phantom measurement results demonstrate improved CR and reduced BV when using Q.Clear instead of OSEM. A beta value of 400 is recommended for oncology body PET/CT using Q.Clear. Copyright © 2015 by the Society of Nuclear Medicine and Molecular Imaging, Inc.
    No preview · Article · Jul 2015 · Journal of Nuclear Medicine

  • No preview · Conference Paper · Apr 2015

  • No preview · Article · Apr 2015 · Journal of Hepatology

  • No preview · Conference Paper · Apr 2015
  • D. Grant · J. Franklin · L. Watts · N. Rahman · FV Gleeson
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    ABSTRACT: Objectives Incidental pulmonary emboli (iPE) are detected in a significant minority of contrast CT scans performed during the management of patients with cancer. These patients are reported to have an increased mortality compared to matched controls. This study investigates outcomes and predictors of mortality following iPE. Methods Reports of all contrast-enhanced CT scans including the chest, excluding dedicated CT pulmonary angiography, performed between 1st May 2012 and 30th September 2013, were searched for prospectively identified iPE. Clinical data was collected from multiple sources, including clinic letters, discharge summaries, and the hospital patient database. Patients presenting with acute symptoms consistent with PE or those already receiving therapeutic anticoagulation were excluded. Potential clinical and radiological predictors of mortality were defined pre-hoc and tested using Student’s t-test and Cox proportional-hazard regression. Results There were 160 cancer patients with iPE. Anticoagulation treatment was given in 97% of cases. Overall 30-day and 6-month mortality following iPE was 20.6% (95% confidence interval 15.0–27.6%) and 52.5% (44.8–60.1%), respectively. Increased 30-day and 6-month mortality was observed in scans performed on inpatients compared to outpatients (38.2% vs 11.4%, p = 0.0004 and 78.2% vs 40.0%, p < 0.0001). 6-month mortality was also increased if this was a new diagnosis of malignancy at the time of the CT scan compared to patients with known malignancy (69.4% vs 46.0%, p = 0.0046), or if metastases were present at the time of CT scan (58.3% vs 26.7%, p = 0.0012). There were 86 (53.8%) central (main or lobar pulmonary arteries), 60 (37.5%) segmental, and 14 (8.8%) subsegmental pulmonary emboli. No significant mortality difference was observed between these radiological features. Conclusion This study has assessed potential poor prognostic features in patients with cancer and iPE. Despite the vast majority receiving therapeutic anticoagulation, there is a high 30-day and 6-month mortality. The benefits of conventional treatment in this clinical situation are as yet unclear.
    No preview · Article · Dec 2014 · Thorax
  • T. N. Matin · X. Xu · T. Doel · V. Grau · N. Rahman · A. Nickol · F. V. Gleeson
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    ABSTRACT: Introduction and objectives To derive quantitative regional imaging lung function parameters using hyperpolarised xenon MRI (Xe-MRI) and computed tomography (QCT), and compare these to pulmonary function tests (PFTs) in subjects with chronic pulmonary obstructive disease (COPD). Methods Twenty patients with COPD (stage II – IV GOLD criteria classification) underwent Xe-MRI at 1.5T, QCT, and PFTs. Whole lung and lobar percentage ventilated volumes were obtained using automated segmentation of multi-slice Xe-MRI ventilation images acquired at a breath hold of FRC + 1L using in-house software. Average whole lung apparent diffusion coefficients (ADCs) were calculated from multi-slice Xe-MRI diffusion-weighted images (b=20.855 sec/cm2). Percentage predicted PFT results were established for each participant. Whole lung and lobar QCT-derived metrics for emphysema and bronchial wall thickness were calculated from percentage of lung tissue with density of <-950 HU and Pi10 (the square root of wall area for an airway with lumen perimeter of 10 mm), respectively. Pearson’s correlation coefficients were used to evaluate the relationship between whole lung and lobar imaging measures and PFTs. Results Xe-MRI whole lung average ADC showed significant correlation with: whole lung QCT percentage emphysema (r = 0.79, p = 0.001), whole lung Pi10 (r = 0.68, p < 0.05), percentage predicted functional residual capacity (FRC) (r = 0.635, p < 0.05) and demonstrated significant negative correlation with percentage predicted TLCO (r= -0.81, p < 0.001). Whole lung QCT percentage emphysema showed a similar significant negative correlation with percentage predicted TLCO (r= -0.80, p < 0.001). Xe-MRI lobar percentage ventilated volume showed significant correlation with lobar QCT percentage emphysema (r= -0.51, p < <0.001). The QCT-derived metrics, percentage emphysema and Pi10 demonstrated significant correlation on a whole lung (r = 0.75, p < 0.015) and lobar basis (r = 0.29, p < 0.015). Conclusion This study demonstrates excellent correlation between Xe-MRI, QCT-derived metrics and PFTs in COPD. New quantitative whole lung and lobar functional imaging parameters have been derived that may be of value when assessing patients with COPD for regional treatment and in trialling new therapies. Although further investigation is required, this may represent the first integrated regional lung imaging technique linked to pulmonary functional outcomes.
    No preview · Article · Dec 2014 · Thorax
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    ABSTRACT: Multidisciplinary team (MDT) meetings are becoming the model of care for cancer patients worldwide. While MDTs have improved the quality of cancer care, the meetings impose substantial time pressure on the members, who generally attend several such MDTs. We describe Lung Cancer Assistant (LCA), a clinical decision support (CDS) prototype designed to assist the experts in the treatment selection decisions in the lung cancer MDTs. A novel feature of LCA is its ability to provide rule-based and probabilistic decision support within a single platform. The guideline-based CDS is based on clinical guideline rules, while the probabilistic CDS is based on a Bayesian network trained on the English Lung Cancer Audit Database (LUCADA). We assess rule-based and probabilistic recommendations based on their concordances with the treatments recorded in LUCADA. Our results reveal that the guideline rule-based recommendations perform well in simulating the recorded treatments with exact and partial concordance rates of 0.57 and 0.79, respectively. On the other hand, the exact and partial concordance rates achieved with probabilistic results are relatively poorer with 0.27 and 0.76. However, probabilistic decision support fulfils a complementary role in providing accurate survival estimations. Compared to recorded treatments, both CDS approaches promote higher resection rates and multimodality treatments.
    Full-text · Article · Sep 2014 · Journal of The Royal Society Interface
  • J.S.Z. Lee · F.V. Gleeson
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    ABSTRACT: Conventional chest radiography remains an important imaging tool for patients with suspected cardiac disease and is usually the first-line imaging investigation performed in both the acute hospital setting and in patients referred from the community. Accurate interpretation allows the diagnosis of structural cardiac abnormalities and of associated abnormalities of the pulmonary vasculature and airways. As picture archiving and communication systems (PACS) are now widely available throughout Europe and the USA, more doctors will have access to images and therefore need to improve their interpretation skills. This chapter provides a basic introduction to the interpretation of a normal chest radiograph and a more detailed look at its use in cardiac disease.
    No preview · Article · Aug 2014 · Medicine
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    ABSTRACT: The definitive diagnosis of pleural malignancy depends upon histological confirmation by pleural biopsy. CT is reported to have a high sensitivity and specificity for the diagnosis of malignant pleural disease, and is part of the routine diagnostic workup of these patients. The aim of this study was to assess the sensitivity and specificity of CT in detecting pleural malignancy prior to definitive histology obtained via thoracoscopy in a large cohort of patients with suspected malignant pleural disease. Retrospective review of thoracoscopies between January 2008 and January 2013 at two UK tertiary referral centres: Oxford and Preston. The histological results were compared with the CT reported diagnosis before the procedure. CT scan reports were assessed by independent respiratory physicians as to whether the radiologist concluded evidence of malignant pleural disease or benign features only. 211 (57%) of 370 patients included in the analysis had malignant disease: CT scans were reported as 'malignant' in 144, giving a sensitivity of 68% (95% CI 62% to 75%). Of the 159 patients with benign disease, 124 had CT scans reported as benign: specificity 78% (72% to 84%). The positive predictive value of a malignant CT report was 80% (75% to 86%), with a negative predictive value of 65% (58% to 72%). A significant proportion of patients being investigated for malignant disease will have malignancy despite a negative CT report. The use of CT alone in determining which patients should have invasive pleural biopsies should be re-evaluated, and further studies to define the diagnostic pathway are now required.
    No preview · Article · Jul 2014 · Thorax

  • No preview · Article · Nov 2013 · Thorax
  • J. S. Z. Lee · K. M. Bradley · F. V. Gleeson

    No preview · Article · Nov 2013 · Thorax
  • J.S. Lee · O.S. Thein · F. Sheerin · R. Macpherson · K. Bradley · F.V. Gleeson

    No preview · Article · Jan 2013 · Lung Cancer

  • No preview · Article · Jan 2013 · Lung Cancer
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    ABSTRACT: A comprehensive framework for predicting response to therapy on the basis of heterogeneity in dceMRI parameter maps is presented. A motion-correction method for dceMRI sequences is extended to incorporate uncertainties in the pharmacokinetic parameter maps using a variational Bayes framework. Simple measures of heterogeneity (with and without uncertainty) in parameter maps for colorectal cancer tumours imaged before therapy are computed, and tested for their ability to distinguish between responders and non-responders to therapy. The statistical analysis demonstrates the importance of using the spatial distribution of parameters, and their uncertainties, when computing heterogeneity measures and using them to predict response on the basis of the pre-therapy scan. The results also demonstrate the benefits of using the ratio of K trans with the bolus arrival time as a biomarker.
    No preview · Article · Jan 2013
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    D M L Tse · N Joshi · E M Anderson · M Brady · F V Gleeson
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    ABSTRACT: The aim of this study was to demonstrate the principle of supporting radiologists by using a computer algorithm to quantitatively analyse MRI morphological features used by radiologists to predict the presence or absence of metastatic disease in local lymph nodes in rectal cancer. A computer algorithm was developed to extract and quantify the following morphological features from MR images: chemical shift artefact; relative mean signal intensity; signal heterogeneity; and nodal size (volume or maximum diameter). Computed predictions on nodal involvement were generated using quantified features in isolation or in combinations. Accuracies of the predictions were assessed against a set of 43 lymph nodes, determined by radiologists as benign (20 nodes) or malignant (23 nodes). Predictions using combinations of quantified features were more accurate than predictions using individual features (0.67-0.86 vs 0.58-0.77, respectively). The algorithm was more accurate when three-dimensional images were used (0.58-0.86) than when only middle image slices (two-dimensional) were used (0.47-0.72). Maximum node diameter was more accurate than node volume in representing the nodal size feature; combinations including maximum node diameter gave accuracies up to 0.91. We have developed a computer algorithm that can support radiologists by quantitatively analysing morphological features of lymph nodes on MRI in the context of rectal cancer nodal staging. We have shown that this algorithm can combine these quantitative indices to generate computed predictions of nodal status which closely match radiological assessment. This study provides support for the feasibility of computer-assisted reading in nodal staging, but requires further refinement and validation with larger data sets.
    Preview · Article · Sep 2012 · The British journal of radiology
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    ABSTRACT: Reports have suggested that a reduction in tumour 18F-fluorodeoxyglucose (FDG) uptake on positron emission tomography (PET) examination during or after neoadjuvant chemotherapy may predict pathological response in oesophageal cancer. Our aim was to determine whether metabolic response predicts pathological response to a standardised neoadjuvant chemotherapy regimen within a prospective clinical trial. Consecutive patients staged with potentially curable oesophageal cancer who underwent treatment within a non-randomised clinical trial were included. A standardised chemotherapy regimen (two cycles of oxaliplatin and 5-fluorouracil) was used. PET/CT was performed before chemotherapy and repeated 24-28 days after the start of cycle 2. Forty-eight subjects were included: mean age 65 years; 37 male. Using the median percentage reduction in SUV(max) (42%) to define metabolic response, pathological response was seen in 71% of metabolic responders (17/24) compared with 33% of non-responders (8/24; P = 0.009, sensitivity 68%, specificity 70%). Pathological response was seen in 81% of subjects with a complete metabolic response (13/16) compared with 38% of those with a less than complete response (12/32; P = 0.0042, sensitivity 52%, specificity 87%). There was no significant histology-based effect. There was a significant association between metabolic response and pathological response; however, accuracy in predicting pathological response was relatively low.
    No preview · Article · May 2012 · European Radiology
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    ABSTRACT: Positron emission tomography combined with computed tomography (PET-CT) is increasingly being used in the staging of oesophageal cancer. Some recent reports suggest it may be used to predict survival. None of these studies, however, reported on the prognostic value of PET-CT performed before neoadjuvant chemotherapy and surgery. The aim of this study was to determine whether pretreatment PET-CT could predict survival. Consecutive patients with oesophageal adenocarcinoma who underwent PET-CT before neoadjuvant chemotherapy and resection were included. Maximum standardized uptake value (SUV(max)), fluorodeoxyglucose (FDG)-avid tumour length and the presence of FDG-avid local lymph nodes were determined for all patients. Kaplan-Meier survival analysis was performed and multivariable analysis used to identify independent prognostic factors. A total of 121 patients were included (mean age 63 years, 97 men) of whom 103 underwent surgical resection. On an intention-to-treat basis, overall survival was significantly worse in patients with FDG-avid local lymph nodes (P < 0·001). SUV(max) and FDG-avid tumour length did not predict survival (P = 0·276 and P = 0·713 respectively). The presence of FDG-avid local lymph nodes was an independent predictor of poor overall survival (hazard ratio (HR) 4·75, 95 per cent confidence interval 2·14 to 10·54; P < 0·001) and disease-free survival (HR 2·97, 1·40 to 6·30; P = 0·004). The presence of FDG-avid lymph nodes, but not SUV(max) or FDG-avid tumour length, was an independent adverse prognostic factor.
    No preview · Article · Feb 2012 · British Journal of Surgery
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    ABSTRACT: PET-CT scans are routinely performed in patients with lung cancer after investigation by chest x-ray (CXR) and CT scan, when these have demonstrated potentially curable disease. If the majority of patients with lung cancer potentially suitable for curative treatment could be identified earlier in the diagnostic pathway on the basis of CXR findings they could be referred for PET-CT imaging without a prior CT scan. We investigated the clinical and financial implications of adopting such a strategy. The details of 1187 patients referred with suspected lung cancer between July 2006 and August 2009 were analysed. The initial CXR and subsequent imaging of patients fit for curative treatment (Performance Status 0/1, FEV1 > 1.0) were reviewed (n = 251). The clinical and financial implications of referring patients for first line PET-CT if deemed potentially curable based on CXR findings were assessed. 107 of 1187 patients had potentially curable lung cancer on PS, lung function, CT and PET-CT. 96 of these 107 patients (90%) were correctly identified on CXR. 149 patients overall were diagnosed as potentially curable on CXR. Referring suitable patients for an immediate PET-CT scan resulted in a reduction in the time to complete staging investigations. Early PET-CT scanning for patients with suspected lung cancer, potentially suitable for curative therapy could result in more efficient staging with little additional cost.
    Full-text · Article · Jan 2012 · Clinical Radiology
  • J.M. Franklin · E.M. Anderson · F.V. Gleeson
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    ABSTRACT: To describe the post-chemoradiotherapy magnetic resonance imaging (MRI) features of locally advanced rectal carcinoma (LARC) in which there has been a complete histopathological response to neoadjuvant chemoradiotherapy (CRT). This retrospective cohort study was performed between January 2005 and November 2009 at a regional cancer centre. Consecutive patients with LARC and a histopathological complete response to long-course CRT were identified. Pre- and post-treatment MRI images were reviewed using a proforma for predefined features and response criteria. ymrT0 was defined as the absence of residual abnormality on MRI. Twenty patients were included in the study. Seven (35%) ypT0 tumours were ymrT0. All 13 ypT0 tumours not achieving ymrT0 appearances had a good radiological response, with at least 65% tumour reduction. The appearances were heterogeneous: in 11/13 patients the tumour was replaced by a region of at least 50% low signal on MRI, with 8/13 having ≥80% low signal, and 3/13 with 100% low signal. MRI may be useful in identifying a complete histopathological response. However, the MRI appearances of ypT0 tumours are heterogeneous and conventional MRI complete response criteria will not detect the majority of patients with a complete histopathological response.
    No preview · Article · Jan 2012 · Clinical Radiology

Publication Stats

3k Citations
646.87 Total Impact Points


  • 2006-2014
    • Oxford University Hospitals NHS Trust
      • Department of Radiology
      Oxford, England, United Kingdom
  • 2009-2013
    • Churchill College
      Cambridge, England, United Kingdom
  • 2012
    • National Institute for Health Research
      Londinium, England, United Kingdom
    • NIHR Oxford Biomedical Research
      Oxford, England, United Kingdom
  • 2009-2010
    • University of Oxford
      • Oxford e-Research Centre
      Oxford, England, United Kingdom
  • 2004
    • Royal Brompton and Harefield NHS Foundation Trust
      Harefield, England, United Kingdom