Publications by authors named "Øystein Olsen"

87 Publications

Traumatic axonal injury on clinical MRI: association with the Glasgow Coma Scale score at scene of injury or at admission and prolonged posttraumatic amnesia.

J Neurosurg 2020 Oct 23:1-12. Epub 2020 Oct 23.

Departments of1Neuromedicine and Movement Science and.

Objective: The aim in this study was to investigate if MRI findings of traumatic axonal injury (TAI) after traumatic brain injury (TBI) are related to the admission Glasgow Coma Scale (GCS) score and prolonged duration of posttraumatic amnesia (PTA).

Methods: A total of 490 patients with mild to severe TBI underwent brain MRI within 6 weeks of injury (mild TBI: median 2 days; moderate to severe TBI: median 8 days). The location of TAI lesions and measures of total TAI lesion burden (number and volume of lesions on FLAIR and diffusion-weighted imaging and number of lesions on T2*-weighted gradient echo or susceptibility-weighted imaging) were quantified in a blinded manner for clinical information. The volume of contusions on FLAIR was likewise recorded. Associations between GCS score and the location and burden of TAI lesions were examined with multiple linear regression, adjusted for age, Marshall CT score (which includes compression of basal cisterns, midline shift, and mass lesions), and alcohol intoxication. The predictive value of TAI lesion location and burden for duration of PTA > 28 days was analyzed with multiple logistic regression, adjusted for age and Marshall CT score. Complete-case analyses of patients with TAI were used for the regression analyses of GCS scores (n = 268) and PTA (n = 252).

Results: TAI lesions were observed in 58% of patients: in 7% of mild, 69% of moderate, and 93% of severe TBI cases. The TAI lesion location associated with the lowest GCS scores were bilateral lesions in the brainstem (mean difference in GCS score -2.5), followed by lesions bilaterally in the thalamus, unilaterally in the brainstem, and lesions in the splenium. The volume of TAI on FLAIR was the measure of total lesion burden most strongly associated with the GCS score. Bilateral TAI lesions in the thalamus had the largest predictive value for PTA > 28 days (OR 16.2, 95% CI 3.9-87.4). Of the measures of total TAI lesion burden, the FLAIR volume of TAI predicted PTA > 28 days the best.

Conclusions: Bilateral TAI lesions in the brainstem and thalamus, as well as the total volume of TAI lesions on FLAIR, had the strongest association with the GCS score and prolonged PTA. The current study proposes a first step toward a modified classification of TAI, with grades ranked according to their relation to these two measures of clinical TBI severity.
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http://dx.doi.org/10.3171/2020.6.JNS20112DOI Listing
October 2020

Yes, and no - evidence on lung ultrasound digested.

Authors:
Øystein E Olsen

Pediatr Radiol 2020 03 17;50(3):305. Epub 2020 Feb 17.

Radiology Department,, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, UK.

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http://dx.doi.org/10.1007/s00247-019-04555-6DOI Listing
March 2020

The role of imaging in the initial investigation of paediatric renal tumours.

Lancet Child Adolesc Health 2020 03 31;4(3):232-241. Epub 2020 Jan 31.

Department of Paediatric Radiology, Great Ormond Street Hospital NHS Foundation Trust, London, UK.

Imaging has a key role in the assessment of paediatric renal tumours, especially when the initial treatment approach is to proceed to standard chemotherapy without histological confirmation. In Europe, according to the International Society of Paediatric Oncology guidelines, core needle biopsy is not routinely done unless the child is older than 10 years. Between age 6 months and 9 years, the child is treated with a standard regimen of preoperative chemotherapy unless there are concerns about non-Wilms' tumour pathology. Atypical imaging findings could therefore stratify a child into a different treatment protocol, and can prompt the need for pretreatment histology. This review details the latest protocols and techniques used in the assessment of paediatric renal tumours. Important imaging findings are discussed, especially the features that might prompt the need for a pretreatment biopsy. Local radiology practices vary, but both MRI and CT are widely used as routine imaging tests for the assessment of paediatric renal tumours in Europe. Advances in imaging technology and MRI sequences are facilitating the development of new techniques, which might increase the utility of imaging in terms of predicting tumour histology and clinical behaviour. Several of these new imaging techniques are outlined here.
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http://dx.doi.org/10.1016/S2352-4642(19)30340-2DOI Listing
March 2020

Actual clinical leadership: a shadowing study of charge nurses and doctors on-call in the emergency department.

Scand J Trauma Resusc Emerg Med 2019 Jan 8;27(1). Epub 2019 Jan 8.

Department of Research, Development and Education, Stavanger University Hospital, Stavanger, Norway.

Background: The provision of safe, high quality healthcare in the Emergency Department (ED) requires frontline healthcare personnel with sufficient competence in clinical leadership. However, healthcare education curriculum infrequently features learning about clinical leadership, and there is an absence of experienced doctors and nurses as role models in EDs for younger and less experienced doctors and nurses. The purpose of this study was to explore the activities performed by clinical leaders and to identify similarities and differences between the activities performed by charge nurses and those performed by doctors on-call in the Emergency Department after completion of a Clinical Leadership course.

Methods: A qualitative exploratory design was chosen. Nine clinical leaders in the ED were shadowed. The data were analyzed using a thematic analysis.

Results: The analysis revealed seven themes: receiving an overview of the team and patients and planning the shift; ensuring resources; monitoring and ensuring appropriate patient flow; monitoring and securing information flow; securing patient care and treatment; securing and assuring the quality of diagnosis and treatment of patient; and securing the prioritization of patients. The last two themes were exclusive to doctors on-call, while the theme "securing patient care and treatment" was exclusive to charge nurses.

Conclusions: Charge nurses and doctors on-call perform multitasking and complement each other as clinical leaders in the ED. The findings in this study provide new insights into how clinical leadership is performed by charge nurses and doctors on-call in the ED, but also the similarities and differences that exist in clinical leadership performance between the two professions. Clinical leadership is necessary to the provision of safe, high quality care and treatment for patients with acute health needs, as well as the coordination of healthcare services in the ED. More evaluation studies of this Clinical Leadership course would be valuable.
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http://dx.doi.org/10.1186/s13049-018-0581-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6323734PMC
January 2019

Relapse of Wilms' tumour and detection methods: a retrospective analysis of the 2001 Renal Tumour Study Group-International Society of Paediatric Oncology Wilms' tumour protocol database.

Lancet Oncol 2018 08 27;19(8):1072-1081. Epub 2018 Jun 27.

Department of Medical Oncology and Hematology, Fondazione IRCCS Istituto Nazionale dei Tumori, Milan, Italy.

Background: Wilms' tumour is the most common renal cancer in childhood and about 15% of patients will relapse. There is scarce evidence about optimal surveillance schedules and methods for detection of tumour relapse after therapy.

Methods: The Renal Tumour Study Group-International Society of Paediatric Oncology (RTSG-SIOP) Wilms' tumour 2001 trial and study is an international, multicentre, prospective registration, biological study with an embedded randomised clinical trial for children with renal tumours aged between 6 months and 18 years. The study covers 243 different centres in 27 countries grouped into five consortia. The current protocol of SIOP surveillance for Wilms' tumour recommends that abdominal ultrasound and chest x-ray should be done every 3 months for the first 2 years after treatment and be repeated every 4-6 months in the third and fourth year and annually in the fifth year. In this retrospective cohort study of the protocol database, we analysed data from participating institutions on timing, anatomical site, and mode of detection of all first relapses of Wilms' tumour. The primary outcomes were how relapse of Wilms' tumour was detected (ie, at or between scheduled surveillance and with or without clinical symptoms, scan modality, and physical examination) and to estimate the number of scans needed to capture one subclinical relapse. The RTSG-SIOP study is registered with Eudra-CT, number 2007-004591-39.

Findings: Between June 26, 2001, and May 8, 2015, of 4271 eligible patients in the 2001 RTSG-SIOP Wilms' tumour database, 538 (13%) relapsed. Median follow-up from surgery was 62 months (IQR 32-93). The method used to detect relapse was registered for 410 (76%) of 538 relapses. Planned surveillance imaging captured 289 (70%) of these 410 relapses. The primary imaging modality used to detect relapse was reported for 251 patients, among which relapse was identified by abdominal ultrasound (80 [32%] patients), chest x-ray (78 [31%]), CT scan of the chest (64 [25%]) or abdomen (20 [8%]), and abdominal MRI (nine [4%]). 279 (68%) of 410 relapses were not detectable by physical examination and 261 (64%) patients did not have clinical symptoms at relapse. The estimated number of scans needed to detect one subclinical relapse during the first 2 years after nephrectomy was 112 (95% CI 106-119) and, for 2-5 years after nephrectomy, 500 (416-588).

Interpretation: Planned surveillance imaging captured more than two-thirds of predominantly asymptomatic relapses of Wilms' tumours, with most detected by abdominal ultrasound, chest x-ray, or chest CT scan. Beyond 2 years post-nephrectomy, a substantial number of surveillance scans are needed to capture one relapse, which places a burden on families and health-care systems.

Funding: Great Ormond Street Hospital Children's Charity, the European Expert Paediatric Oncology Reference Network for Diagnostics and Treatment, The Danish Childhood Cancer Foundation, Cancer Research UK, the UK National Cancer Research Network and Children's Cancer and Leukaemia Group, Société Française des Cancers de l'Enfant and Association Leon Berard Enfant Cancéreux and Enfant et Santé, Gesellschaft für Pädiatrische Onkologie und Hämatologie and Deutsche Krebshilfe, Grupo Cooperativo Brasileiro para o Tratamento do Tumor de Wilms and Sociedade Brasileira de Oncologia Pediátrica, the Spanish Society of Pediatric Haematology and Oncology and the Spanish Association Against Cancer, and SIOP-Netherlands.
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http://dx.doi.org/10.1016/S1470-2045(18)30293-6DOI Listing
August 2018

Detecting inflammation in inflammatory bowel disease - how does ultrasound compare to magnetic resonance enterography using standardised scoring systems?

Pediatr Radiol 2018 06 13;48(6):843-851. Epub 2018 Apr 13.

Department of Paediatric Radiology, Great Ormond Street Hospital NHS Foundation Trust, London, Wc1N 3JH, UK.

Background: Magnetic resonance enterography (MRE) is the current gold standard for imaging in inflammatory bowel disease, but ultrasound (US) is a potential alternative.

Objective: To determine whether US is as good as MRE for the detecting inflamed bowel, using a combined consensus score as the reference standard.

Materials And Methods: We conducted a retrospective cohort study in children and adolescents <18 years with inflammatory bowel disease (IBD) at a tertiary and quaternary centre. We included children who underwent MRE and US within 4 weeks. We scored MRE using the London score and US using a score adapted from the METRIC (MR Enterography or Ultrasound in Crohn's Disease) trial. Four gastroenterologists assessed an independent clinical consensus score. A combined consensus score using the imaging and clinical scores was agreed upon and used as the reference standard to compare MRE with US.

Results: We included 53 children. At a whole-patient level, MRE scores were 2% higher than US scores. We used Lin coefficient to assess inter-observer variability. The repeatability of MRE scores was poor (Lin 0.6). Agreement for US scoring was substantial (Lin 0.95). There was a significant positive correlation between MRE and clinical consensus scores (Spearman's rho = 0.598, P=0.0053) and US and clinical consensus scores (Spearman's rho = 0.657, P=0.0016).

Conclusion: US detects as much clinically significant bowel disease as MRE. It is possible that MRE overestimates the presence of disease when using a scoring system. This study demonstrates the feasibility of using a clinical consensus reference standard in paediatric IBD imaging studies.
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http://dx.doi.org/10.1007/s00247-018-4084-1DOI Listing
June 2018

Pediatric Radiology Editorial Board - acknowledgments and updates.

Pediatr Radiol 2018 01;48(1)

Radiology Department, Great Ormond Street Hospital for Children, Great Ormond Street, London, UK.

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http://dx.doi.org/10.1007/s00247-017-4051-2DOI Listing
January 2018

Reply to Andronikou and Sergot: 'point-of-care' ultrasound.

Authors:
Øystein E Olsen

Pediatr Radiol 2017 12;47(13):1851-1852

Radiology Department, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, United Kingdom.

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http://dx.doi.org/10.1007/s00247-017-3980-0DOI Listing
December 2017

Apparent diffusion coefficient as it relates to histopathology findings in post-chemotherapy nephroblastoma: a feasibility study.

Pediatr Radiol 2017 Nov 1;47(12):1608-1614. Epub 2017 Jul 1.

Department of Radiology, Great Ormond Street Hospital for Children, London, UK.

Background: Nephroblastomas represent a group of heterogeneous tumours with variable proportions of distinct histopathological components.

Objective: The purpose of this study was to investigate whether direct comparison of apparent diffusion coefficient (ADC) measurements with post-resection histopathology subtypes is feasible and whether ADC metrics are related to histopathological components.

Materials And Methods: Twenty-three children were eligible for inclusion in this retrospective study. All children had MRI including diffusion-weighted imaging (DWI) after preoperative chemotherapy, just before tumour resection. A pathologist and radiologist identified corresponding slices at MRI and postoperative specimens using tumour morphology, the upper/lower calyx and hilar vessels as reference points. An experienced reader performed ADC measurements, excluding non-enhancing areas. A pathologist reviewed the corresponding postoperative slides according to the international standard guidelines. We tested potential associations with the Spearman rank test.

Results: Side-by-side comparison of MRI-DWI with corresponding histopathology slides was feasible in 15 transverse slices in 9 lesions in 8 patients. Most exclusions were related to extensive areas of necrosis/haemorrhage. In one lesion correlation was not possible because of the different orientation of sectioning of the specimen and MRI slices. The 25% ADC showed a strong relationship with percentage of blastema (Spearman rho=-0.71, P=0.003), whereas median ADC was strongly related to the percentage stroma (Spearman rho=0.74, P=0.002) at histopathology.

Conclusion: Side-by-side comparison of MRI-DWI and histopathology is feasible in the majority of patients who do not have massive necrosis and hemorrhage. Blastemal and stromal components have a strong linear relationship with ADC markers.
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http://dx.doi.org/10.1007/s00247-017-3931-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5658478PMC
November 2017

Paediatric magnetic resonance enteroclysis under general anaesthesia - initial experience.

Pediatr Radiol 2017 Jun 6;47(7):877-883. Epub 2017 Apr 6.

Department of Paediatric Radiology, Great Ormond Street Hospital NHS Foundation Trust, London, Wc1N 3JH, UK.

MR enterography is the accepted imaging reference standard for small bowel assessment in inflammatory bowel disease. There is an increasing cohort of children with inflammatory bowel disease presenting at an early age (<5 years) with severe disease. Younger children present a technical challenge for enterography because of the need for sedation/general anaesthesia to allow image optimisation and the need for oral contrast to allow adequate luminal assessment. Through our experiences, MR enteroclysis under general anaesthesia has proven to be a successful imaging technique for the work-up of these patients. In this paper, we present our institutional practice for performing MR enteroclysis under general anaesthesia.
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http://dx.doi.org/10.1007/s00247-017-3836-7DOI Listing
June 2017

Pediatric Radiology editorial board - acknowledgments and updates.

Pediatr Radiol 2017 Jan;47(1)

Radiology Department,, Great Ormond Street Hospital for Children,, Great Ormond Street, London, WC1N 3JH, UK.

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http://dx.doi.org/10.1007/s00247-016-3757-xDOI Listing
January 2017

Whole-tumor apparent diffusion coefficient measurements in nephroblastoma: Can it identify blastemal predominance?

J Magn Reson Imaging 2017 05 11;45(5):1316-1324. Epub 2016 Oct 11.

Department of Radiology, Great Ormond Street Hospital for Children, London, UK.

Purpose: To explore the potential relation between whole-tumor apparent diffusion coefficient (ADC) parameters in viable parts of tumor and histopathological findings in nephroblastoma.

Materials And Methods: Children (n = 52) with histopathologically proven nephroblastoma underwent diffusion-weighted magnetic resonance imaging (MRI) (1.5T) before preoperative chemotherapy. Of these, 25 underwent an additional MRI after preoperative chemotherapy, shortly before resection. An experienced reader performed the whole-tumor ADC measurements of all lesions, excluding nonenhancing areas. An experienced pathologist reviewed the postoperative specimens according to standard SIOP guidelines. Potential associations between ADC parameters and proportions of histological subtypes were assessed with Pearson's or Spearman's rank correlation coefficient depending on whether the parameters tested were normally distributed. In case the Mann-Whitney U-test revealed significantly different ADC values in a subtype tumor, this ADC parameter was used to derive a receiver operating characteristic (ROC) curve.

Results: The 25 percentile ADC at presentation was the best ADC metric correlated with proportion of blastema (Pearson's r = -0.303, P = 0.026). ADC after preoperative treatment showed moderate correlation with proportion stromal subtype at histopathology (r = 0.579, P = 0.002). By ROC analysis, the optimal threshold of median ADC for detecting stromal subtype was 1.362 × 10 mm /s with sensitivity and specificity of 100% (95% confidence interval [CI] 0.65-1.00) and 78.9% (95% CI 0.57-0.92), respectively.

Conclusion: ADC markers in nephroblastoma are related to stromal subtype histopathology; however, identification of blastemal predominant tumors using whole-tumor ADC measurements is probably not feasible.

Level Of Evidence: 3 J. MAGN. RESON. IMAGING 2017;45:1316-1324.
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http://dx.doi.org/10.1002/jmri.25506DOI Listing
May 2017

Interprofessional trust in emergency department - as experienced by nurses in charge and doctors on call.

J Clin Nurs 2016 Nov 15;25(21-22):3252-3260. Epub 2016 Aug 15.

Department of Health Studies, Faculty of Social Sciences, University of Stavanger, Stavanger, Norway.

Aims And Objectives: The aim of this study was to describe that which characterises interprofessional trust in a Norwegian emergency department, as expressed by nurses in charge and doctors on call.

Background: Interprofessional trust requires knowledge of and skills in interprofessional collaboration. It also requires established trust in fellow collaborators, as well as in the work environment and in the more comprehensive system in which the work is conducted. Nurses in charge and doctors on call who collaborate in the context of an emergency department do so under changing conditions in terms of staff composition and work load.

Design: The study was designed in a qualitative, inductive and sequential manner.

Method: Data were collected from September-November 2013 through four focus group interviews and was analysed by means of qualitative content analysis.

Results: The data revealed two themes that were characteristic of interprofessional trust: 'having relational knowledge' and 'being part of a context'. Together, the themes can be understood as equally important to contextual collaboration. A model of interprofessional trust between an individual level and system level was developed from the results.

Conclusion: The study indicates that interprofessional trust is a changeable phenomenon that has great impact on the possibility for development at an individual level and at a more abstract system level.

Relevance To Clinical Practice: Interprofessional trust can be improved by focusing on trust-building activities between staff at the individual level and between staff and organisation at the system level. Supportive activities such as continuous interprofessional education are suggested as valuable to the development and maintenance of trust.
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http://dx.doi.org/10.1111/jocn.13359DOI Listing
November 2016

Impact of clinical leadership in teams' course on quality, efficiency, responsiveness and trust in the emergency department: study protocol of a trailing research study.

BMJ Open 2016 08 10;6(8):e011899. Epub 2016 Aug 10.

Emergency Department, Stavanger University Hospital, Stavanger, Norway Global Health Priorities Research Group, Department of Global Public Health and Primary Care, Center for International Health, University of Bergen, Bergen, Norway.

Introduction: Clinical leadership has long been recognised as critical for optimising patient safety, quality of care and interprofessional teamwork in busy and stressful healthcare settings. There is a need to compensate for the absence of the conventional mentor-to-apprentice transfer of clinical leadership knowledge and skills. While young doctors and nurses are increasingly proficient in medical, surgical and technical skills, their training in, and knowledge of clinical leadership skills, is not adequate to meet the demands for these non-technical skills in the emergency department. Thus, the purpose of the paper is to present and discuss the study protocol of clinical leadership in a course for teams that aims to improve quality, efficiency, responsiveness of healthcare services and collegial trust in the emergency department.

Methods And Analysis: The study employs a trailing research design using multiple quantitative and qualitative methods in the summative (pretest and post-test) and formative evaluation. Quantitative data have been collected from a patient questionnaire, the emergency departments' database and by the observation of team performance. Qualitative data have been collected by shadowing healthcare professionals and through focus group interviews. To ensure trustworthiness in the data analysis, we will apply member checks and analyst triangulation, in addition to providing contextual and sample description to allow for evaluation of transferability of our results to other contexts and groups.

Ethics And Dissemination: The study is approved by the ethics committee of the western part of Norway and the hospital. The study is based on voluntary participation and informed written consent. Informants can withdraw at any point in time. The results will be disseminated at research conferences, peer review journals and through public presentations to people outside the scientific community.
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http://dx.doi.org/10.1136/bmjopen-2016-011899DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4985869PMC
August 2016

Intra-Tumor Genetic Heterogeneity in Wilms Tumor: Clonal Evolution and Clinical Implications.

EBioMedicine 2016 Jul 27;9:120-129. Epub 2016 May 27.

UCL Institute of Child Health, London, United Kingdom; Department of Histopathology, Great Ormond Street Hospital, London, United Kingdom. Electronic address:

The evolution of pediatric solid tumors is poorly understood. There is conflicting evidence of intra-tumor genetic homogeneity vs. heterogeneity (ITGH) in a small number of studies in pediatric solid tumors. A number of copy number aberrations (CNA) are proposed as prognostic biomarkers to stratify patients, for example 1q+ in Wilms tumor (WT); current clinical trials use only one sample per tumor to profile this genetic biomarker. We multisampled 20 WT cases and assessed genome-wide allele-specific CNA and loss of heterozygosity, and inferred tumor evolution, using Illumina CytoSNP12v2.1 arrays, a custom analysis pipeline, and the MEDICC algorithm. We found remarkable diversity of ITGH and evolutionary trajectories in WT. 1q+ is heterogeneous in the majority of tumors with this change, with variable evolutionary timing. We estimate that at least three samples per tumor are needed to detect >95% of cases with 1q+. In contrast, somatic 11p15 LOH is uniformly an early event in WT development. We find evidence of two separate tumor origins in unilateral disease with divergent histology, and in bilateral WT. We also show subclonal changes related to differential response to chemotherapy. Rational trial design to include biomarkers in risk stratification requires tumor multisampling and reliable delineation of ITGH and tumor evolution.
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http://dx.doi.org/10.1016/j.ebiom.2016.05.029DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4972528PMC
July 2016

Access and utilisation of healthcare services in rural Tanzania: A comparison of public and non-public facilities using quality, equity, and trust dimensions.

Glob Public Health 2016 17;11(4):407-22. Epub 2016 Feb 17.

a National Institute for Medical Research , Dar es Salaam , Tanzania.

This study compared the access and utilisation of health services in public and non-public health facilities in terms of quality, equity and trust in the Mbarali district, Tanzania. Interviews, focus group discussions, and informal discussions were used to generate data. Of the 1836 respondents, 1157 and 679 respondents sought healthcare services on their last visit at public or non-public health facilities, respectively. While 45.5% rated the quality of services to be good in both types of facilities, reported medicine shortages were more pronounced among those who visited public rather than non-public health facilities (OR = 1.7, 95% CI 1.4, 2.1). Respondents who visited public facilities were 4.9 times less likely than those who visited non-public facilities to emphasise the influence of cost in accessing and utilising health care (OR = 4.9, CI 3.9-6.1). A significant difference was also found in the provider-client relationship satisfaction level between non-public (89.1%) and public facilities (74.7%) (OR = 2.8, CI: 1.5-5.0), indicating a level of lower trust in the later. Revised strategies are needed to ensure availability of medicines in public facilities, which are used by the majority of the population, while strengthening private-public partnerships to harmonise healthcare costs.
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http://dx.doi.org/10.1080/17441692.2015.1132750DOI Listing
December 2016

Pediatric Radiology editorial board - acknowledgments and updates.

Pediatr Radiol 2016 Jan;46(1):2-3

Radiology Department, Great Ormond Street Hospital for Children,, Great Ormond Street, London, WC1N 3JH, UK.

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http://dx.doi.org/10.1007/s00247-015-3508-4DOI Listing
January 2016

The numbers games.

Authors:
Øystein E Olsen

Pediatr Radiol 2016 Jan 21;46(1):4-5. Epub 2015 Dec 21.

Radiology Department, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, UK.

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http://dx.doi.org/10.1007/s00247-015-3527-1DOI Listing
January 2016

Comparison of diagnostic performance for perinatal and paediatric post-mortem imaging: CT versus MRI.

Eur Radiol 2016 Jul 21;26(7):2327-36. Epub 2015 Oct 21.

Great Ormond Street Hospital NHS Foundation Trust, London, UK.

Objectives: To compare the diagnostic yield of whole-body post-mortem computed tomography (PMCT) imaging to post-mortem magnetic resonance (PMMR) imaging in a prospective study of fetuses and children.

Methods: We compared PMCT and PMMR to conventional autopsy as the gold standard for the detection of (a) major pathological abnormalities related to the cause of death and (b) all diagnostic findings in five different body organ systems.

Results: Eighty two cases (53 fetuses and 29 children) underwent PMCT and PMMR prior to autopsy, at which 55 major abnormalities were identified. Significantly more PMCT than PMMR examinations were non-diagnostic (18/82 vs. 4/82; 21.9 % vs. 4.9 %, diff 17.1 % (95 % CI 6.7, 27.6; p < 0.05)). PMMR gave an accurate diagnosis in 24/55 (43.64 %; 95 % CI 31.37, 56.73 %) compared to 18/55 PMCT (32.73 %; 95 % CI 21.81, 45.90). PMCT was particularly poor in fetuses <24 weeks, with 28.6 % (8.1, 46.4 %) more non-diagnostic scans. Where both PMCT and PMMR were diagnostic, PMMR gave slightly higher diagnostic accuracy than PMCT (62.8 % vs. 59.4 %).

Conclusion: Unenhanced PMCT has limited value in detection of major pathology primarily because of poor-quality, non-diagnostic fetal images. On this basis, PMMR should be the modality of choice for non-invasive PM imaging in fetuses and children.

Key Points: • Overall 17.1 % more PMCT examinations than PMMR were non-diagnostic • 28.6 % more PMCT were non-diagnostic than PMMR in fetuses <24 weeks • PMMR detected almost a third more pathological abnormalities than PMCT • PMMR gave slightly higher diagnostic accuracy when both were diagnostic.
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http://dx.doi.org/10.1007/s00330-015-4057-9DOI Listing
July 2016

A multi-Gaussian model for apparent diffusion coefficient histogram analysis of Wilms' tumour subtype and response to chemotherapy.

NMR Biomed 2015 Aug 9;28(8):948-57. Epub 2015 Jun 9.

Developmental Imaging and Biophysics Section, Institute of Child Health, University College London, London, UK.

Wilms' tumours (WTs) are large heterogeneous tumours, which typically consist of a mixture of histological cell types, together with regions of chemotherapy-induced regressive change and necrosis. The predominant cell type in a WT is assessed histologically following nephrectomy, and used to assess the tumour subtype and potential risk. The purpose of this study was to develop a mathematical model to identify subregions within WTs with distinct cellular environments in vivo, determined using apparent diffusion coefficient (ADC) values from diffusion-weighted imaging (DWI). We recorded the WT subtype from the histopathology of 32 tumours resected in patients who received DWI prior to surgery after pre-operative chemotherapy had been administered. In 23 of these tumours, DWI data were also available prior to chemotherapy. Histograms of ADC values were analysed using a multi-Gaussian model fitting procedure, which identified 'subpopulations' with distinct cellular environments within the tumour volume. The mean and lower quartile ADC values of the predominant viable tissue subpopulation (ADC(1MEAN), ADC(1LQ)), together with the same parameters from the entire tumour volume (ADC(0MEAN), ADC(0LQ)), were tested as predictors of WT subtype. ADC(1LQ) from the multi-Gaussian model was the most effective parameter for the stratification of WT subtype, with significantly lower values observed in high-risk blastemal-type WTs compared with intermediate-risk stromal, regressive and mixed-type WTs (p < 0.05). No significant difference in ADC(1LQ) was found between blastemal-type and intermediate-risk epithelial-type WTs. The predominant viable tissue subpopulation in every stromal-type WT underwent a positive shift in ADC(1MEAN) after chemotherapy. Our results suggest that our multi-Gaussian model is a useful tool for differentiating distinct cellular regions within WTs, which helps to identify the predominant histological cell type in the tumour in vivo. This shows potential for improving the risk-based stratification of patients at an early stage, and for guiding biopsies to target the most malignant part of the tumour.
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http://dx.doi.org/10.1002/nbm.3337DOI Listing
August 2015

Intra- and interobserver variability of whole-tumour apparent diffusion coefficient measurements in nephroblastoma: a pilot study.

Pediatr Radiol 2015 Oct 8;45(11):1651-60. Epub 2015 May 8.

Department of Radiology, Great Ormond Street Hospital for Children, London, UK.

Background: The apparent diffusion coefficient (ADC) is potentially useful for assessing treatment response in nephroblastoma (Wilms tumour). However the precision of ADC measurements in these heterogeneous lesions is unknown.

Objective: To assess intra- and interobserver variability of whole-tumour ADC measurements in viable parts of nephroblastomas at diagnosis and after preoperative chemotherapy.

Materials And Methods: We included children with histopathologically proven nephroblastoma who had undergone MRI with diffusion-weighted imaging before and after preoperative chemotherapy. Three independent observers performed whole-tumour ADC measurements of all lesions, excluding non-enhancing areas. One observer evaluated all lesions on two occasions. We performed analyses using Bland-Altman plots and concordance correlation coefficient (CCC) calculations with 95% limits of agreement for median ADC, difference between pre- and post-chemotherapy median ADC (ADC shift) and percentage of pixels with ADC values <1.0 × 10(-3) mm(2)/s.

Results: In 22 lesions (13 pretreatment and 9 post-treatment) in 10 children the interobserver variability in median ADC and ADC shift were within the interval of approximately ±0.1 × 10(-3) mm(2)/s (limits of agreement for median ADC ranged -0.08-0.11 × 10(-3) mm(2)/s and for ADC-shift -0.11-0.09 × 10(-3) mm(2)/s). The interobserver variability for percentage of low-ADC pixels was larger and also biased. The calculated CCC confirmed good intra- and interobserver agreement (ρ-c ranging from 0.968 to 0.996).

Conclusion: Measurements of whole-tumour ADC values excluding necrotic areas seem to be sufficiently precise for detection of chemotherapy-related change.
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http://dx.doi.org/10.1007/s00247-015-3354-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4577543PMC
October 2015

Diagnostic influence of routine point-of-care pocket-size ultrasound examinations performed by medical residents.

J Ultrasound Med 2015 Apr;34(4):627-36

Levanger Hospital, Nord-Trøndelag Health Trust, Levanger, Norway (G.N.A., T.G., K.S., J.O.K., Ø.O., H.D.); Medical Imaging Laboratory (G.N.A., O.C.M., B.O.H., H.D.), Department of Circulation and Medical Imaging (G.N.A., O.C.M., B.O.H., H.D.), and Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway; and Clinic of Cardiology, St Olav Trondheim University Hospital, Trondheim, Norway (O.C.M., B.O.H.).

Objectives: We aimed to investigate the potential benefit of adding goal-directed ultrasound examinations performed by on-call medical residents using a pocket-size imaging device in patients admitted to a medical department.

Methods: A total of 992 emergency admissions to the medical department at a nonuniversity hospital in Norway were included. Patients admitted on dates with an on-call medical resident randomized to use a pocket-size imaging device were eligible for pocket-size cardiac and abdominal ultrasound examinations or standard care. The cardiac examination included estimation of right and left ventricular sizes and global systolic function and regional left ventricular systolic function, evaluation for pleural and pericardial effusion, and valvular disease. The abdominal examination looked for signs of gross abnormalities of the liver, gallbladder, abdominal aorta, inferior vena cava, and urinary system. Six of 12 medical residents with limited ultrasound experience were randomized to perform the examinations. Diagnostic corrections were made, and findings were confirmed by reference standard diagnostics.

Results: A total of 199 patients were examined. Median times used were 5.7 minutes for the cardiac examination and 4.7 minutes for the abdominal examination. In 13 patients (6.5%), the examination resulted in a major change in the primary diagnosis. In 21 patients (10.5%), the diagnosis was verified, and in 48 (24.0%), an additional important diagnosis was made.

Conclusions: By implementing pocket-size ultrasound examinations that took less than 11 minutes to the usual care, we corrected, verified, or added important diagnoses in more than 1 of 3 emergency medical admissions. Point-of-care examinations with a pocket-size imaging device increased medical residents' diagnostic accuracy and capability.
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http://dx.doi.org/10.7863/ultra.34.4.627DOI Listing
April 2015

Focused ultrasound of the pleural cavities and the pericardium by nurses after cardiac surgery.

Scand Cardiovasc J 2015 Feb 6;49(1):56-63. Epub 2015 Feb 6.

Department of Medicine, Levanger Hospital, Nord-Trøndelag Health Trust , Levanger , Norway.

Objectives: We aimed to study the feasibility and reliability of focused ultrasound (US) examinations to quantify pericardial (PE)- and pleural effusion (PLE) by a pocket-size imaging device (PSID) performed by nurses in patients early after cardiac surgery.

Design: After a 3-month training period, with cardiologists as supervisors, two nurses examined 59 patients (20 women) with US using a PSID at a median of 5 days after cardiac surgery. The amount of PE and PLE was classified in four categories by US (both) and chest x-ray (PLE only). Echocardiography, including US of the pleural cavities, by experienced cardiologists was used as reference.

Results: Focused US by the nurses was more sensitive than x-ray to detect PLE. The correlations of the quantification of PE and PLE by the nurses and reference was r (95% confidence interval) 0.76 (0.46-0.89) and 0.81 (0.73-0.89), both p < 0.001. PE and PLE were drained in one and six (eight cavities) patients, all classified as large amount by the nurses.

Conclusions: Cardiac nurses were able to obtain reliable measurements and quantification of both PE and PLE bedside by focused US and outperform the commonly used chest x-ray regarding PLE after cardiac surgery.
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http://dx.doi.org/10.3109/14017431.2015.1009383DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4389761PMC
February 2015

Why measure tumours?

Authors:
Øystein E Olsen

Pediatr Radiol 2015 Jan 1;45(1):35-41. Epub 2015 Jan 1.

Radiology Department, Great Ormond Street Hospital for Children NHS Foundation Trust, London, WC1N 3JH, UK,

This article questions the scientific justification of ingrained radiologic practices exemplified by size measurements of childhood solid tumours. This is approached by a critical review of staging systems from a selection of paediatric oncological treatment protocols. Local staging remains size-dependent for some tumour types. The consequent stage assignment can significantly influence treatment intensity. Still, the protocols tend not to give precise guidance on how to perform scans and standardise measurements. Also, they do not estimate or account for the inevitable variability in measurements. Counts and measurements of lung nodules are, within some tumour groups, used for diagnosis of metastatic disease. There is, however, no evidence that nodule size is a useful discriminator of benign and malignant lung nodules. The efficacy of imaging depends chiefly on observations being precise, accurate and valid for the desired diagnostic purpose. Because measurements without estimates of their errors are meaningless, studies of variability dependent on tumour shape and location, imaging device and observer need to be encouraged. Reproducible observations make good candidates for staging parameters if they have prognostic validity and at the same time show little covariation with (thereby adding new information to) the existing staging system. The lack of scientific rigour has made the validity of size measurement very difficult to assess. Action is needed, the most important being radiologists' active contribution in development of oncological staging systems, attention to standardisation, knowledge about errors in measurement and protection against undue influence of such errors in the staging of the individual child.
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http://dx.doi.org/10.1007/s00247-014-3148-0DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4281379PMC
January 2015

Diagnostic accuracy of post mortem MRI for abdominal abnormalities in foetuses and children.

Eur J Radiol 2015 Mar 3;84(3):474-481. Epub 2014 Dec 3.

Department of Histopathology, UCL Institute of Child Health & Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK. Electronic address:

Background: To compare the diagnostic accuracy of post-mortem magnetic resonance imaging (PMMR) specifically for abdominal pathology in foetuses and children, compared to conventional autopsy.

Methods: Institutional ethics approval and parental consent was obtained. 400 unselected foetuses and children underwent PMMR using a 1.5T Siemens Avanto MR scanner before conventional autopsy. PMMR images and autopsy findings were reported blinded to the other data respectively.

Results: Abdominal abnormalities were found in 70/400 (12%) autopsies. Overall sensitivity and specificity (95% confidence interval) of PMMR for abdominal pathology was 72.5% (61.0, 81.6) and 90.8% (87.0, 93.6), with positive (PPV) and negative predictive values (NPV) of 64.1% (53.0, 73.9) and 93.6% (90.2, 95.8) respectively. PMMR was good at detecting renal abnormalities (sensitivity 80%), particularly in foetuses, and relatively poor at detecting intestinal abnormalities (sensitivity 50%). Overall accuracy was 87.4% (83.6, 90.4).

Conclusions: PMMR has high overall accuracy for abdominal pathology in foetuses, newborns and children. PMMR is particularly good at detecting renal abnormalities, and relatively poor at detecting intestinal abnormalities. In clinical practice, PMMR may be a useful alternative or adjunct to conventional autopsy in foetuses and children for detecting abdominal abnormalities.
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http://dx.doi.org/10.1016/j.ejrad.2014.11.030DOI Listing
March 2015

Using the unmet obstetric needs indicator to map inequities in life-saving obstetric interventions at the local health care system in Kenya.

Int J Equity Health 2014 Dec 12;13:112. Epub 2014 Dec 12.

Centre for Public Health Research Institute, Kenya Medical Research Institute (KEMRI), Nairobi, Kenya.

Background: Developing countries with high maternal mortality need to invest in indicators that not only provide information about how many women are dying, but also where, and what can be done to prevent these deaths. The unmet Obstetric Needs (UONs) concept provides this information. This concept was applied at district level in Kenya to assess how many women had UONs and where the women with unmet needs were located.

Methods: A facility based retrospective study was conducted in 2010 in Malindi District, Kenya. Data on pregnant women who underwent a major obstetric intervention (MOI) or died in facilities that provide comprehensive Emergency Obstetric Care (EmOC) services in 2008 and 2009 were collected. The difference between the number of women who experienced life threatening obstetric complications and those who received care was quantified. The main outcome measures in the study were the magnitude of UONs and their geographical distribution.

Results: 566 women in 2008 and 724 in 2009 underwent MOI. Of these, 185 (32.7%) in 2008 and 204 (28.1%) in 2009 were for Absolute Maternal Indications (AMI). The most common MOI was caesarean section (90%), commonly indicated by Cephalopelvic Disproportion (CPD)-narrow pelvis (27.6% in 2008; 26.1% in 2009). Based on a reference rate of 1.4%, the overall MOI for AMI rate was 1.25% in 2008 and 1.3% in 2009. In absolute terms, 22 (11%) women in 2008 and 12 (6%) in 2009, who required a life saving intervention failed to get it. Deficits in terms of unmet needs were identified in rural areas only while urban areas had rates higher than the reference rate (0.8% vs. 2.2% in 2008; 0.8% vs. 2.1% in 2009).

Conclusions: The findings, if used as a proxy to maternal mortality, suggest that rural women face higher risks of dying during pregnancy and childbirth. This indicates the need to improve priority setting towards ensuring equity in access to life saving interventions for pregnant women in underserved areas.
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http://dx.doi.org/10.1186/s12939-014-0112-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4268791PMC
December 2014

Fusion and subtraction post-processing in body MRI.

Pediatr Radiol 2015 Feb 2;45(2):273-82. Epub 2014 Sep 2.

Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, Great Ormond Street, London, WC1N 3JH, UK,

Interpreting complex paediatric body MRI studies requires the integration of information from multiple sequences. Image processing software, some freely available, allows the radiologist to use simple and rapid post-processing techniques that may aid diagnosis. We demonstrate the use of fusion and subtraction post-processing techniques with examples from four areas of application: enterography, oncological imaging, musculoskeletal imaging and MR fistulography.
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http://dx.doi.org/10.1007/s00247-014-3129-3DOI Listing
February 2015

Diagnostic accuracy of post-mortem MRI for thoracic abnormalities in fetuses and children.

Eur Radiol 2014 Nov 31;24(11):2876-84. Epub 2014 Aug 31.

Department of Radiology, Great Ormond Street Hospital for Children NHS Foundation Trust, London, UK,

Objectives: To compare the diagnostic accuracy of post-mortem magnetic resonance imaging (PMMR) specifically for non-cardiac thoracic pathology in fetuses and children, compared with conventional autopsy.

Methods: Institutional ethics approval and parental consent was obtained. A total of 400 unselected fetuses and children underwent PMMR before conventional autopsy, reported blinded to the other dataset.

Results: Of 400 non-cardiac thoracic abnormalities, 113 (28 %) were found at autopsy. Overall sensitivity and specificity (95 % confidence interval) of PMMR for any thoracic pathology was poor at 39.6 % (31.0, 48.9) and 85.5 % (80.7, 89.2) respectively, with positive predictive value (PPV) 53.7 % (42.9, 64.0) and negative predictive value (NPV) 77.0 % (71.8, 81.4). Overall agreement was 71.8 % (67.1, 76.2). PMMR was most sensitive at detecting anatomical abnormalities, including pleural effusions and lung or thoracic hypoplasia, but particularly poor at detecting infection.

Conclusions: PMMR currently has relatively poor diagnostic detection rates for the commonest intra-thoracic pathologies identified at autopsy in fetuses and children, including respiratory tract infection and diffuse alveolar haemorrhage. The reasonable NPV suggests that normal thoracic appearances at PMMR exclude the majority of important thoracic lesions at autopsy, and so could be useful in the context of minimally invasive autopsy for detecting non-cardiac thoracic abnormalities.

Key Points: • PMMR has relatively poor diagnostic detection rates for common intrathoracic pathology • The moderate NPV suggests that normal PMMR appearances exclude most important abnormalities • Lung sampling at autopsy remains the "gold standard" for pulmonary pathology.
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http://dx.doi.org/10.1007/s00330-014-3313-8DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4182596PMC
November 2014

The accountability for reasonableness approach to guide priority setting in health systems within limited resources--findings from action research at district level in Kenya, Tanzania, and Zambia.

Health Res Policy Syst 2014 Aug 20;12:49. Epub 2014 Aug 20.

DBL - Centre for Health Research and Development, Faculty of Health and Medical Sciences, University of Copenhagen, Thorvaldsensvej 57, DK 1871 Frederiksberg, Denmark.

Background: Priority-setting decisions are based on an important, but not sufficient set of values and thus lead to disagreement on priorities. Accountability for Reasonableness (AFR) is an ethics-based approach to a legitimate and fair priority-setting process that builds upon four conditions: relevance, publicity, appeals, and enforcement, which facilitate agreement on priority-setting decisions and gain support for their implementation. This paper focuses on the assessment of AFR within the project REsponse to ACcountable priority setting for Trust in health systems (REACT).

Methods: This intervention study applied an action research methodology to assess implementation of AFR in one district in Kenya, Tanzania, and Zambia, respectively. The assessments focused on selected disease, program, and managerial areas. An implementing action research team of core health team members and supporting researchers was formed to implement, and continually assess and improve the application of the four conditions. Researchers evaluated the intervention using qualitative and quantitative data collection and analysis methods.

Results: The values underlying the AFR approach were in all three districts well-aligned with general values expressed by both service providers and community representatives. There was some variation in the interpretations and actual use of the AFR in the decision-making processes in the three districts, and its effect ranged from an increase in awareness of the importance of fairness to a broadened engagement of health team members and other stakeholders in priority setting and other decision-making processes.

Conclusions: District stakeholders were able to take greater charge of closing the gap between nationally set planning and the local realities and demands of the served communities within the limited resources at hand. This study thus indicates that the operationalization of the four broadly defined and linked conditions is both possible and seems to be responding to an actual demand. This provides arguments for the continued application and further assessment of the potential of AFR in supporting priority-setting and other decision-making processes in health systems to achieve better agreed and more sustainable health improvements linked to a mutual democratic learning with potential wider implications.
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http://dx.doi.org/10.1186/1478-4505-12-49DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4237792PMC
August 2014
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