Oystein E Olsen

George Eliot Hospital NHS Trust, Nuneaton, England, United Kingdom

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Publications (40)166.35 Total impact

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    Alex Weller, Joy L Barber, Oystein E Olsen
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    ABSTRACT: Nephrogenic systemic fibrosis (NSF) is a multisystem disease seen exclusively in patients with renal impairment. It can be severely debilitating and sometimes fatal. There is a strong association with gadolinium-based contrast agents used in magnetic resonance imaging (MRI). Risk factors include renal impairment and proinflammatory conditions, e.g. major surgery and vascular events. Although there is no single effective treatment for NSF, the most successful outcomes are seen following restoration of renal function, either following recovery from acute kidney injury or following renal transplantation. There have been ten biopsy-proved pediatric cases of NSF, with no convincing evidence that children have a significantly altered risk compared with the adult population. After implementation of guidelines restricting the use of gadolinium-based contrast agents in at-risk patients, there has been a sharp reduction in new cases and no new reports in children. Continued vigilance is recommended: screening for renal impairment, use of more stable gadolinium chelates, consideration of non-contrast-enhanced MRI or alternative imaging modalities where appropriate.
    Pediatric Nephrology 10/2013; · 2.94 Impact Factor
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    ABSTRACT: BACKGROUND: Post-mortem MRI is a potential diagnostic alternative to conventional autopsy, but few large prospective studies have compared its accuracy with that of conventional autopsy. We assessed the accuracy of whole-body, post-mortem MRI for detection of major pathological lesions associated with death in a prospective cohort of fetuses and children. METHODS: In this prospective validation study, we did pre-autopsy, post-mortem, whole-body MRI at 1·5 T in an unselected population of fetuses (≤24 weeks' or >24 weeks' gestation) and children (aged <16 years) at two UK centres in London between March 1, 2007 and Sept 30, 2011. With conventional autopsy as the diagnostic gold standard, we assessed MRI findings alone, or in conjunction with other minimally invasive post-mortem investigations (minimally invasive autopsy), for accuracy in detection of cause of death or major pathological abnormalities. A radiologist and pathologist who were masked to the autopsy findings indicated whether the minimally invasive autopsy would have been adequate. The primary outcome was concordance rate between minimally invasive and conventional autopsy. FINDINGS: We analysed 400 cases, of which 277 (69%) were fetuses and 123 (31%) were children. Cause of death or major pathological lesion detected by minimally invasive autopsy was concordant with conventional autopsy in 357 (89·3%, 95% CI 85·8-91·9) cases: 175 (94·6%, 90·3-97·0) of 185 fetuses at 24 weeks' gestation or less, 88 (95·7%, 89·3-98·3) of 92 fetuses at more than 24 weeks' gestation, 34 (81·0%, 67·7-90·0) of 42 newborns aged 1 month or younger, 45 (84·9%, 72·9-92·1) of 53 infants aged older than 1 month to 1 year or younger, and 15 (53·6%, 35·8-70·5) of 28 children aged older than 1 year to 16 years or younger. The dedicated radiologist or pathologist review of the minimally invasive autopsy showed that in 165 (41%) cases a full autopsy might not have been needed; in these cases, concordance between autopsy and minimally invasive autopsy was 99·4% (96·6-99·9). INTERPRETATION: Minimally invasive autopsy has accuracy similar to that of conventional autopsy for detection of cause of death or major pathological abnormality after death in fetuses, newborns, and infants, but was less accurate in older children. If undertaken jointly by pathologists and radiologists, minimally invasive autopsy could be an acceptable alternative to conventional autopsy in selected cases. FUNDING: Policy research Programme, Department of Health, UK.
    The Lancet 01/2013; · 39.06 Impact Factor
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    ABSTRACT: Magnetic resonance imaging (MRI), frequently with contrast enhancement, is the preferred imaging modality for many indications in children. Practice varies widely between centers, reflecting the rapid pace of change and the need for further research. Guide-line changes, for example on contrast-medium choice, require continued practice reappraisal. This article reviews recent developments in pediatric contrast-enhanced MRI and offers recommendations on current best practice. Nine leading pediatric radiologists from internationally recognized radiology centers convened at a consensus meeting in Bordeaux, France, to discuss applications of contrast-enhanced MRI across a range of indications in children. Review of the literature indicated that few published data provide guidance on best practice in pediatric MRI. Discussion among the experts concluded that MRI is preferred over ionizing-radiation modalities for many indications, with advantages in safety and efficacy. Awareness of age-specific adaptations in MRI technique can optimize image quality. Gadolinium-based contrast media are recommended for enhancing imaging quality. The choice of most appropriate contrast medium should be based on criteria of safety, tolerability, and efficacy, characterized in age-specific clinical trials and personal experience.
    Magnetic Resonance Insights 01/2013; 6:95-111.
  • Sílvia Costa Dias, Oystein E Olsen
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    ABSTRACT: MRI has a fundamental role in paediatric imaging. The T2-weighted fast/turbo spin-echo sequence is important because it has high signal-to-noise ratio compared to gradient-echo sequences. It is usually acquired as 2-D sections in one or more planes. Volumetric spin-echo has until recently only been possible with very long echo times due to blurring of the soft-tissue contrast with long echo trains. A new 3-D spin-echo sequence uses variable flip angles to overcome this problem. It may reproduce useful soft-tissue contrast, with improved spatial resolution. Its isotropic capability allows subsequent reconstruction in standard, curved or arbitrary planes. It may be particularly useful for visualisation of small lesions, or if large lesions distort the usual anatomical relations. We present clinical examples, describe the technical parameters and discuss some potential artefacts and optimisation of image quality.
    Pediatric Radiology 08/2012; 42(11):1385-90. · 1.57 Impact Factor
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    ABSTRACT: Minimally invasive autopsy by post mortem magnetic resonance (MR) imaging has been suggested as an alternative for conventional autopsy in view of the declining consented autopsy rates. However, large prospective studies rigorously evaluating the accuracy of such an approach are lacking. We intend to compare the accuracy of a minimally invasive autopsy approach using post mortem MR imaging with that of conventional autopsy in fetuses, newborns and children for detection of the major pathological abnormalities and/or determination of the cause of death. We recruited 400 consecutive fetuses, newborns and children referred for conventional autopsy to one of the two participating hospitals over a three-year period. We acquired whole body post mortem MR imaging using a 1.5 T MR scanner (Avanto, Siemens Medical Solutions, Enlargen, Germany) prior to autopsy. The total scan time varied between 90 to 120 minutes. Each MR image was reported by a team of four specialist radiologists (paediatric neuroradiology, paediatric cardiology, paediatric chest & abdominal imaging and musculoskeletal imaging), blinded to the autopsy data. Conventional autopsy was performed according to the guidelines set down by the Royal College of Pathologists (UK) by experienced paediatric or perinatal pathologists, blinded to the MR data. The MR and autopsy data were recorded using predefined categorical variables by an independent person. Using conventional post mortem as the gold standard comparator, the MR images will be assessed for accuracy of the anatomical morphology, associated lesions, clinical usefulness of information and determination of the cause of death. The sensitivities, specificities and predictive values of post mortem MR alone and MR imaging along with other minimally invasive post mortem investigations will be presented for the final diagnosis, broad diagnostic categories and for specific diagnosis of each system. NCT01417962 NIHR PORTFOLIO NUMBER: 6794.
    BMC Pediatrics 12/2011; 11:120. · 1.98 Impact Factor
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    Oystein E Olsen, Catherine M Owens
    Pediatric Radiology 09/2011; 41(9):1219. · 1.57 Impact Factor
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    Øystein E Olsen, Catherine M Owens
    Pediatric Radiology 06/2011; 41(7):799-800. · 1.57 Impact Factor
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    ABSTRACT: In our experience, diffusion-weighted imaging with body background suppression (DWIBS) is hard to interpret in children who commonly have foci of restricted diffusion in their skeletons unrelated to pathology, sometimes in an asymmetrical pattern. This raises serious concern about the accuracy of DWIBS in cancer staging in children. To describe the signal distribution at DWIBS in the normal developing lumbar spine and pelvic skeleton. Forty-two healthy children underwent an MR DWIBS sequence of the abdomen and pelvis. An axial short-tau inversion-recovery (STIR) echo-planar imaging (EPI) pulse sequence was used. Two radiologists did a primary review of the images and based on these preliminary observations, separate scoring systems for the lumbar spine, pelvis and proximal femoral epiphyses/femoral heads were devised. Visual evaluation of the images was then performed by the two radiologists in consensus. The scoring was repeated separately 2 months later by a third radiologist. Restricted diffusion was defined as areas of high signal compared to the background. Coronal maximum intensity projection (MIP) reformats were used to assess the vertebral bodies. For the pelvis, the extension of high signal for each bone was given a score of 0 to 4. Cohen's Kappa interobserver agreement coefficients of signal distribution and asymmetry were calculated. All children had areas of high signal, both within the lumbar vertebral bodies and within the pelvic skeleton. Three patterns of signal distribution were seen in the lumbar spine, but no specific pattern was seen in the pelvis. There was a tendency toward a reduction of relative area of high signal within each bone with age, but also a widespread interindividual variation. Restricted diffusion is a normal finding in the pelvic skeleton and lumbar spine in children with an asymmetrical distribution seen in 48% of normal children in this study. DWIBS should be used with caution for cancer staging in children as this could lead to high numbers of false positive findings or even unjustified upstaging.
    Pediatric Radiology 02/2011; 41(2):221-6. · 1.57 Impact Factor
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    ABSTRACT: Apparent diffusion coefficient (ADC) relates to tissue cellularity, and change in ADC during chemotherapy may be a promising tool for assessing oncological response. To investigate the feasibility of measuring changes in ADC distribution in solid abdominal and pelvic paediatric tumours during chemotherapy, and to assess patterns of change. Consecutive children were included in a prospective observational study. ADC maps were calculated at presentation and following chemotherapy from a diffusion-sensitised sequence. ADC distribution in the whole tumour, excluding areas of low or absent gadolinium-enhancement, was investigated. Change during chemotherapy was assessed for each patient individually. Histopathological slices from the resected specimens were reviewed. There were seven children (nine tumours) included in the study. ADC in all except one deviated from a normal distribution. All tumours changed their ADC distribution during chemotherapy. Median ADC increased in all upper abdominal tumours, but more in tumours with histopathologically good or marked response to chemotherapy. Seven out of nine tumours attained a wider ADC distribution, the remaining two showed little chemotherapy response. ADC distribution changes during chemotherapy in childhood abdominal tumours are measurable. Distinct patterns of shift can be observed and ADC change is therefore promising as a noninvasive biomarker for therapy response.
    Pediatric Radiology 01/2011; 41(1):99-106. · 1.57 Impact Factor
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    ABSTRACT: To compare the diagnostic performance of rapid whole-body anatomic magnetic resonance (MR) staging of pediatric and adolescent lymphoma to an enhanced positron emission tomographic (PET)/computed tomographic (CT) reference standard. Ethical permission was given by the University College London Hospital ethics committee, and informed written consent was obtained from all participants and/or parents or guardians. Thirty-one subjects (age range, 7.3-18.0 years; 18 male, 11 female) with histologically proved lymphoma were prospectively recruited. Pretreatment staging was performed with whole-body short inversion time inversion-recovery (STIR) half-Fourier rapid acquisition with relaxation enhancement (RARE) MR imaging, fluorine 18 fluorodeoxyglucose PET/CT, and contrast agent-enhanced chest CT. Twenty-six subjects had posttreatment PET/CT and compromised our final cohort. Eleven nodal and 11 extranodal sites per patient were assessed on MR imaging by two radiologists in consensus, with a nodal short-axis threshold of >1 cm and predefined extranodal positivity criteria. The same sites were independantly evaluated by two nuclear medicine physicians on PET/CT images. Disease positivity was defined as a maximum standardized uptake value >2.5 or nodal size >1 cm. An unblinded expert panel reevaluated the imaging findings, removing perceptual errors, and derived an enhanced PET/CT reference standard (taking into account chest CT and 3-month follow-up imaging) against which the reported and intrinsic performance of MR imaging was assessed by using the kappa statistic. There was very good agreement between MR imaging and the enhanced PET/CT reference standard for nodal and extranodal staging (kappa = 0.96 and 0.86, respectively) which improved following elimination of perceptual errors (kappa = 0.97 and 0.91, respectively). The sensitivity and specificity of MR imaging (following removal of perceptual error) were 98% and 99%, respectively, for nodal disease and 91% and 99%, respectively, for extranodal disease. Whole-body STIR half-Fourier RARE MR imaging of pediatric and adolescent lymphoma can accurately depict nodal and extranodal disease and may provide an alternative nonionizing imaging method for anatomic disease assessment at initial staging.
    Radiology 04/2010; 255(1):182-90. · 6.34 Impact Factor
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    ABSTRACT: Ultrasound has been the method of choice for antenatal fetal assessment for the past three decades; however, problems may arise in cases of oligohydramnion, unfavorable position of the fetus, and maternal obesity. To compare ultrasound (US) and magnetic resonance imaging (MRI) for common fetal measurements at 19-30 weeks' gestation, and to assess the effect of high maternal body-mass index (BMI). 59 low-risk singleton pregnancies were enrolled in a prospective blinded cross-sectional study. In a first session, an experienced obstetrician used a high-resolution US technique and in a second session on the same day MRI was used to measure biparietal diameter (BPD), head circumference (HC), mean abdominal diameter (MAD), abdominal circumference (AC), and femur length (FL). Inter- and intraobserver and intermodality variability was determined using Bland-Altman plots. The effect of maternal BMI was assessed using Spearman's statistics. A total of 45 women aged 19-43 years (median 29 years) attended both US and MRI at median 22 weeks' gestation. The mean differences between US and MRI were 1.6 mm for HC (95% confidence interval [CI] -1.0, 4.3 mm), 1 mm for AC (95% CI -0.2, 4.0 mm), 0.2 mm for MAD (95% CI -0.7, 1.2 mm), 2.2 mm for BPD (95% CI 1.7, 2.7 mm), and 4.6 mm for FL (95% CI 2.9, 6.4 mm). Maternal BMI did not affect the results (Spearman' rho 0.054-0.277; P=NS). The intraobserver agreement for all MRI measurements was acceptable, except for FL, while the interobserver agreement was poor. There was good agreement between US and MRI for common fetal measurements, but not for all (i.e., BPD and particularly FL). MRI had a poor interobserver agreement, underscoring the need for technical refinement and reference ranges specifically established for MRI.
    Acta Radiologica 02/2010; 51(1):85-91. · 1.33 Impact Factor
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    ABSTRACT: This study explores the relationship between MRI Apparent Diffusion Coefficient (ADC) and PET Standardized Uptake Value (SUV) measurements in pediatric Hodgkin lymphoma. Sixteen patients (mean age 15.4 yrs, 8 male) with proven Hodgkin lymphoma were recruited and staged using PET-CT, anatomical MRI and additional 1.5T diffusion weighted imaging (DWI) prior to and following chemotherapy. Pre-treatment lymph nodes and anatomically paired post-treatment residual tissue located on MRI were matched to the corresponding PET-CT. Region of interest (ROI) analysis was used to extract quantitative measurements. Mean ADC (ADC(mean)) and maximum SUV (SUV(max)) were recorded and correlation assessed using Spearman statistics. Fifty-three ROIs were sampled. Pre- and post-treatment ADC(mean) ranged from 0.77 × 10(−3) to 1.79 × 10(−3) (median 1.15 × 10(−3) mm(2)s(−1)) and 1.08 × 10(−3) to 3.18 ×10(−3) (median 1.88 × 10(−3) mm(2)s(−1)), and SUV(max) from 2.60 to 25.4 (median 8.85 mg/ml) and 1.00 to 3.50 mg/ml (median 1.90 mg/ml). Median post-treatment ADC(mean) was higher, and median SUV(max) lower than pretreatment values (p < 0.0001). There was an inverse correlation between pre-treatment ADC(mean) and SUV(max) (p = 0.005) and between fractional change ([post-treatment – pre-treatment]/pre-treatment)in ADC(mean) and SUV(max) (p =0.002). Our results confirm a strong reciprocal relationship between nodal ADC(mean) and SUV(max) in Hodgkin lymphoma;supporting the potential application of quantitative DWI as a functional biomarker of disease.
    Cancer biomarkers: section A of Disease markers 01/2010; 7(4):249-59. · 0.97 Impact Factor
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    ABSTRACT: More than 10 years ago, conventional whole-body MRI at 1.5 Tesla (T) was proposed as a more rapid, less invasive alternative to conventional invasive perinatal autopsy. However, there is poor agreement between the perinatal autopsy findings and the postmortem MRI at 1.5 T. Studies in small animals have shown that good images of anatomy can be obtained using high-field MRI at 9.4 T and have led to the present investigation. This prospective blinded study compared the diagnostic accuracy of high-field MRI at 9.4 T and conventional MRI for postmortem examination of small human fetuses. A total of 18 fetuses of less than 22 weeks' gestation were examined using 3-dimensional T2-weighted fast-spin echo sequences for whole-body MRI with 1.5 T and 9.4 T scanners before invasive autopsy. The MRI images for each system were compared to the invasive autopsy findings by investigators who were blinded to the MRI settings. Tissue contrast in 14 different regions for MRI images at 1.5 T and 9.4 T was compared separately and in a random order. The quality of the MRI images was rated on a 4-point scale. For all organ systems, high-field MRI at 9.4 T provided superior image quality scores than conventional MRI at 1.5 T and provided greater spatial resolution, higher tissue contrast, and better diagnostic information. High-field MRI also was able to detect all the structural abnormalities in fetal organs found with invasive autopsy. In contrast, conventional MRI had no diagnostic value in 14 (78%) of the cases. These findings indicate that use of MRI at 9.4 T may be a satisfactory noninvasive alternative to conventional autopsy in both large and small human fetuses.
    Obstetrical and Gynecological Survey 11/2009; 64(12):787-789. · 2.51 Impact Factor
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    ABSTRACT: Conventional whole-body MRI at 1.5 T does not provide adequate image quality of small fetuses, thus reducing its potential for use as an alternative to invasive autopsy. High-field whole-body MRI at 9.4 T provides good images of small animals. We therefore compared the diagnostic usefulness of high-field MRI with conventional MRI for post-mortem examination of human fetuses. We did whole-body MRI at 9.4 T and 1.5 T on 18 fetuses of less than 22 weeks' gestation, using three-dimensional T(2)-weighted fast-spin echo sequences, before doing invasive autopsy. Images obtained with MRI for each system were compared with the findings of invasive autopsy in a blinded manner. Tissue contrast of 14 different regions was compared on 1.5 T and 9.4 T images that were provided by paediatric radiologists separately and in a random order, and image quality was scored on a four-point scale. The primary endpoint was diagnostic accuracy. Spatial resolution, tissue contrast, and image quality of all organ systems were much better with high-field MRI than with conventional MRI. All structural abnormalities that were detected with invasive autopsy and internal examination of visceral organs were also detected with high-field MRI, whereas conventional MRI was not diagnostically useful in 14 (78%) cases. Whole-body high-field MRI is a feasible option for post-mortem examination of human fetuses, and can provide good tissue characterisation even in small fetuses (5 g). The use of MRI at 9.4 T might be helpful in the development of a minimally invasive perinatal autopsy system. Department of Health Policy Research Programme, British Heart Foundation, National Institute of Health Research, Higher Education Funding Council for England, Biotechnology and Biological Sciences Research Council, Engineering and Physical Sciences Research Council, Great Ormond Street Hospital, University College London (UCL) Institute of Child Health, UCL Hospital, and UCL.
    The Lancet 09/2009; 374(9688):467-75. · 39.06 Impact Factor
  • European Respiratory Journal 04/2009; 33(3):694-9. · 6.36 Impact Factor
  • Oystein Olsen
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    ABSTRACT: The scope of this review is to discuss a theoretical approach to imaging policy, particularly in the perspective of radiation risk reduction. Decisions are ideally driven by empirical evidence about efficacy and risk, e.g., in classical hierarchical efficacy model. As a result of the paucity of empirical evidence (inevitable because of rapid technological development), a pragmatic model is needed. This should avoid overemphasis of factors that currently seem to hamper change, namely personal preference, local expertise, infrastructure, availability. Extrapolation of current general knowledge about CT and MRI demonstrates how a pragmatic approach can be applied in the real world with intermediate goals such as (1) channeling patients from CT to MRI, and (2) reducing CT-delivered radiation. Increased utilisation of MRI in body imaging requires optimisation of scan protocols and equipment, and, being a very operator-dependent modality, the active involvement of the radiologist. In CT dose reduction the main challenge is to benchmark the minimum radiation-dose requirement, and therefore the minimum required image quality that is diagnostically acceptable. As this will ultimately depend on pre-test likelihoods in institutional populations, it is difficult to issue general guidance, and local assessment remains a cornerstone in this effort.
    Pediatric Radiology 01/2009; · 1.57 Impact Factor
  • Oystein E Olsen
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    ABSTRACT: This review is aimed at practicing radiologists and technicians, and seeks to explore the main factors influencing quality in body magnetic resonance imaging (MRI), paediatric in particular. Important considerations include the selection of voxel size, striking the right balance between achievable signal-to-noise ratio (SNR) versus allowable motion artefact when adjusting the acquisition time, and optimising image contrast, which often is inherently different compared with adult pathologies. Based on this, optimisation of staple pulse sequences, and a practical approach to body imaging, will be discussed in more detail.
    European Journal of Radiology 10/2008; 68(2):299-308. · 2.51 Impact Factor
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    ABSTRACT: Radiological evaluation before renal transplantation includes imaging of vascular anatomy, as thrombosis, narrowing and anomalies of the inferior vena cava (IVC) and/or iliac veins (IV) can influence the surgical technique. Most cases only require investigation with Doppler vessel ultrasonography (US), with magnetic resonance venography (MRV) reserved to clarify US findings and investigate high-risk patients. The purpose of this study was to compare these modalities in evaluating IVC and IV and correlate imaging and operative findings of patients at RTx surgery. Twenty-nine children, 21 (72%) of whom had subsequent RTx surgery, were investigated over 5 years with correlation of US and MRV in 62% (18 of 29). Technically difficult US examinations needing MRV for clarification occurred in six (21%), and normal US with anatomical variations on MRV was seen in three (10%). The anatomical variations consisted of left-sided IVC, aberrant right common femoral vein and a left IV partly draining into the azygos and renal veins. US is an excellent screening tool for evaluating vascular anatomy patency in children. MRV infrequently contributes beneficial information, is difficult to justify as a screening tool, and due to the risks of gadolinium in uraemia, should only be used on an individual patient basis.
    Pediatric Nephrology 08/2008; 23(7):1157-62. · 2.94 Impact Factor
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    ABSTRACT: Nephrogenic systemic fibrosis (NSF) is a relatively new entity, first described in 1997. Few cases have been reported, but the disease has high morbidity and mortality. To date it has been seen exclusively in patients with renal dysfunction. There is an emerging link with intravenous injection of gadolinium contrast agents, which has been suggested as a main triggering factor, with a lag time of days to weeks. Risk factors include the severity of renal impairment, major surgery, vascular events and other proinflammatory conditions. There is no reason to believe that children have an altered risk compared to the adult population. It is important that the paediatric radiologist acknowledges emerging information on NSF but at the same time considers the risk:benefit ratio prior to embarking on alternative investigations, as children with chronic kidney disease require high-quality diagnostic imaging.
    Pediatric Radiology 06/2008; 38(5):489-96; quiz 602-3. · 1.57 Impact Factor
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    Øystein E Olsen
    [Show abstract] [Hide abstract]
    ABSTRACT: The scope of this review is to discuss a theoretical approach to imaging policy, particularly in the perspective of radiation risk reduction. Decisions are ideally driven by empirical evidence about efficacy and risk, e.g., in classical hierarchical efficacy model. As a result of the paucity of empirical evidence (inevitable because of rapid technological development), a pragmatic model is needed. This should avoid overemphasis of factors that currently seem to hamper change, namely personal preference, local expertise, infrastructure, availability. Extrapolation of current general knowledge about CT and MRI demonstrates how a pragmatic approach can be applied in the real world with intermediate goals such as (1) channeling patients from CT to MRI, and (2) reducing CT-delivered radiation. Increased utilisation of MRI in body imaging requires optimisation of scan protocols and equipment, and, being a very operator-dependent modality, the active involvement of the radiologist. In CT dose reduction the main challenge is to benchmark the minimum radiation-dose requirement, and therefore the minimum required image quality that is diagnostically acceptable. As this will ultimately depend on pre-test likelihoods in institutional populations, it is difficult to issue general guidance, and local assessment remains a cornerstone in this effort.
    Pediatric Radiology 06/2008; 38 Suppl 3:S452-8. · 1.57 Impact Factor

Publication Stats

421 Citations
166.35 Total Impact Points

Institutions

  • 2013
    • George Eliot Hospital NHS Trust
      Nuneaton, England, United Kingdom
  • 2008–2013
    • University College London
      • • Institute for Women's Health
      • • Institute of Child Health
      Londinium, England, United Kingdom
  • 2004–2013
    • Great Ormond Street Hospital for Children NHS Foundation Trust
      • Department of Radiology
      Londinium, England, United Kingdom
    • University of Surrey
      Guilford, England, United Kingdom
  • 2011
    • University Hospital of North Norway
      • Department of Radiology
      Tromsø, Troms Fylke, Norway
  • 2001–2010
    • Haukeland University Hospital
      • Department of Radiology
      Bergen, Hordaland Fylke, Norway