title: Feasibility of diffusion-weighted magnetic resonance imaging in patients with juvenile idiopathic arthritis on 1.0-T open-bore MRI.
abstract: OBJECTIVE
  To evaluate the feasibility of non-invasive diffusion-weighted imaging (DWI) of the knee of children with juvenile idiopathic arthritis (JIA) and, further, to analyze the apparent diffusion coefficient (ADC) levels to distinguish synovium from effusion.
  
  
  METHODS
  Standard magnetic resonance imaging of the knee including post-contrast imaging was obtained in eight patients (mean age, 12 years 8 months, five females) using an open-bore magnetic resonance imaging system (1.0 T). In addition, axially acquired echo-planar DWI datasets (b-values 0, 50, and 600) were prospectively obtained and the diffusion images were post-processed into ADC50-600 maps. Two independent observers selected a region of interest (ROI) for both synovium and effusion using aligned post-contrast images as landmarks. Mann-Whitney U test was performed to compare ADC synovium and ADC effusion.
  
  
  RESULTS
  DWI was successfully obtained in all patients. When data of both observers was combined, ADC synovium was lower than ADC effusion in the ROI in seven out of eight patients (median, 1.92 × 10(-3) mm(2)/s vs. 2.40 × 10(-3) mm(2)/s, p = 0.006, respectively). Similar results were obtained when the two observers were analyzed separately (observer 1: p = 0.006, observer 2: p = 0.04).
  
  
  CONCLUSIONS
  In this pilot study, on a patient-friendly 1.0-T open-bore MRI, we demonstrated that DWI may potentially be a feasible non-invasive imaging technique in children with JIA. We could differentiate synovium from effusion in seven out of eight patients based on the ADC of synovium and effusion. However, to select synovium and effusion on DWI, post-contrast images were still a necessity.
authors.affiliation: Department of Radiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. a.m.barendregt@amc.uva.nl.|Department of Pediatric Hematology, Immunology, Rheumatology and Infectious Disease, Emma Children's Hospital AMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands. a.m.barendregt@amc.uva.nl.
authors.forename: Anouk M
authors.initials: AM
authors.lastname: Barendregt
authors.affiliation: Department of Radiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.|Department of Pediatric Hematology, Immunology, Rheumatology and Infectious Disease, Emma Children's Hospital AMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
authors.forename: Charlotte M
authors.initials: CM
authors.lastname: Nusman
authors.affiliation: Department of Radiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
authors.forename: Robert
authors.initials: R
authors.lastname: Hemke
authors.affiliation: Department of Radiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
authors.forename: Cristina
authors.initials: C
authors.lastname: Lavini
authors.affiliation: Radiology Department, St. Mary's Hospital, Imperial College Healthcare NHS Trust, Praed Street, Paddington, London, W2 1NY, UK.
authors.forename: Dimitri
authors.initials: D
authors.lastname: Amiras
authors.affiliation: Department of Pediatric Hematology, Immunology, Rheumatology and Infectious Disease, Emma Children's Hospital AMC, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
authors.forename: Taco W
authors.initials: TW
authors.lastname: Kuijpers
authors.affiliation: Department of Radiology, Academic Medical Center, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
authors.forename: Mario
authors.initials: M
authors.lastname: Maas
mesh_terms: D000293:Adolescent; D001171:Arthritis, Juvenile / Q000473:pathology*; D002648:Child; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000295:instrumentation / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000295:instrumentation / Q000379:methods*; D008297:Male; D015588:Observer Variation; D010865:Pilot Projects; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013582:Synovial Fluid / Q000166:cytology*; D013583:Synovial Membrane / Q000473:pathology*
keywords: Arthritis; Diffusion-weighted imaging; Juvenile idiopathic arthritis; Knee joint; Magnetic resonance imaging; Synovial membrane