title: Whole-Body Diffusion-Weighted Imaging in Chronic Recurrent Multifocal Osteomyelitis in Children.
abstract: OBJECTIVE
  Chronic recurrent multifocal osteomyelitis/ chronic non-bacterial osteomyelitis (CRMO/ CNO) is a rare auto-inflammatory disease and typically manifests in terms of musculoskeletal pain. Because of a high frequency of musculoskeletal disorders in children/ adolescents, it can be quite challenging to distinguish CRMO/ CNO from nonspecific musculoskeletal pain or from malignancies. The purpose of this study was to evaluate the visibility of CRMO lesions in a whole-body diffusion-weighted imaging (WB-DWI) technique and its potential clinical value to better characterize MR-visible lesions.
  
  
  METHODS
  Whole-body imaging at 3T was performed in 16 patients (average: 13 years) with confirmed CRMO. The protocol included 2D Short Tau Inversion Recovery (STIR) imaging in coronal and axial orientation as well as diffusion-weighted imaging in axial orientation. Visibility of lesions in DWI and STIR was evaluated by two readers in consensus. The apparent diffusion coefficient (ADC) was measured for every lesion and corresponding reference locations.
  
  
  RESULTS
  A total of 33 lesions (on average 2 per patient) visible in STIR and DWI images (b = 800 s/mm2 and ADC maps) were included, predominantly located in the long bones. With a mean value of 1283 mm2/s in lesions, the ADC was significantly higher than in corresponding reference regions (782 mm2/s). By calculating the ratio (lesion to reference), 82% of all lesions showed a relative signal increase of 10% or higher and 76% (25 lesions) showed a signal increase of more than 15%. The median relative signal increase was 69%.
  
  
  CONCLUSIONS
  This study shows that WB-DWI can be reliably performed in children at 3T and predominantly, the ADC values were substantially elevated in CRMO lesions. WB-DWI in conjunction with clinical data is seen as a promising technique to distinguish benign inflammatory processes (in terms of increased ADC values) from particular malignancies.
authors.affiliation: Department of Paediatric Radiology, Leipzig University Hospital, Leipzig, Germany.
authors.forename: Nadine
authors.initials: N
authors.lastname: Leclair
authors.affiliation: Siemens Healthcare GmbH, Diagnostic Imaging, Magnetic Resonance Imaging, Erlangen, Germany.
authors.forename: Gregor
authors.initials: G
authors.lastname: Thörmer
authors.affiliation: Department of Paediatric Radiology, Leipzig University Hospital, Leipzig, Germany.
authors.forename: Ina
authors.initials: I
authors.lastname: Sorge
authors.affiliation: Department of Paediatric Radiology, Leipzig University Hospital, Leipzig, Germany.
authors.forename: Lutz
authors.initials: L
authors.lastname: Ritter
authors.affiliation: Department of Paediatric Rheumatology, Leipzig University Hospital, Leipzig, Germany.
authors.forename: Volker
authors.initials: V
authors.lastname: Schuster
authors.affiliation: Department of Paediatric Radiology, Leipzig University Hospital, Leipzig, Germany.
authors.forename: Franz Wolfgang
authors.initials: FW
authors.lastname: Hirsch
mesh_terms: D000293:Adolescent; D002648:Child; D003937:Diagnosis, Differential; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D010019:Osteomyelitis / Q000175:diagnosis* / Q000473:pathology; D015203:Reproducibility of Results; D051598:Whole Body Imaging