title: Novel automated system for magnetic resonance imaging quantification of the inflamed synovial membrane volume in patients with juvenile idiopathic arthritis.
abstract: OBJECTIVE
  To introduce a novel automated method for the quantification of the inflamed synovial membrane volume (SV) using magnetic resonance imaging (MRI), and to investigate its feasibility and validity in patients with juvenile idiopathic arthritis (JIA).
  
  
  METHODS
  The tool was tested on 58 patients with JIA and wrist involvement. Thirty-six patients had a 1-year MRI followup. MRI of the clinically more affected wrist was performed using a 1.5T scanner and a Flex small coil. An algorithmic approach, based on supervised voxel classification for automatic estimation of SV in a 3-dimensional MRI, was developed. The SV was estimated as the number of positively classified voxels and then normalized by the patient's body surface (NSV). Validation procedures included the analysis of reliability, construct validity, responsiveness to change, discriminant validity, and the predictive value.
  
  
  RESULTS
  The agreement between the automated estimation of NSV and the manual measurements was excellent (intraclass correlation coefficient 0.93, 95% confidence interval 0.79-0.98). The automatic NSV demonstrated good construct validity by yielding strong correlations with local signs of disease activity and a moderate correlation with global physician assessment of disease activity and with the Rheumatoid Arthritis Magnetic Resonance Imaging Scoring system synovitis score. NSV showed a strong responsiveness to clinical change (standardized response mean values >1) and satisfactory discriminant validity. High baseline NSV (>4.6) had high predictive value (100%) with respect to erosive progression.
  
  
  CONCLUSIONS
  The proposed automated method allowed reliable quantification of NSV, which represents a promising imaging biomarker of disease activity in JIA. The automated system has the potential to improve the longitudinal assessment of JIA and to predict progressive joint destruction.
authors.affiliation: Istituto Giannina Gaslini, Genova, Italy. claramalattia@ospedale-gaslini.ge.it
authors.forename: C
authors.initials: C
authors.lastname: Malattia
authors.forename: M B
authors.initials: MB
authors.lastname: Damasio
authors.forename: C
authors.initials: C
authors.lastname: Basso
authors.forename: M
authors.initials: M
authors.lastname: Santoro
authors.forename: A
authors.initials: A
authors.lastname: Verri
authors.forename: S
authors.initials: S
authors.lastname: Pederzoli
authors.forename: C
authors.initials: C
authors.lastname: Mattiuz
authors.forename: S
authors.initials: S
authors.lastname: Viola
authors.forename: A
authors.initials: A
authors.lastname: Buoncompagni
authors.forename: A
authors.initials: A
authors.lastname: Madeo
authors.forename: M
authors.initials: M
authors.lastname: Mazzoni
authors.forename: K
authors.initials: K
authors.lastname: Rosendahl
authors.forename: K
authors.initials: K
authors.lastname: Lambot-Juhan
authors.forename: L
authors.initials: L
authors.lastname: Tanturri de Horatio
authors.forename: G M
authors.initials: GM
authors.lastname: Magnano
authors.forename: A
authors.initials: A
authors.lastname: Ravelli
authors.forename: A
authors.initials: A
authors.lastname: Martini
mesh_terms: D000293:Adolescent; D000465:Algorithms; D001171:Arthritis, Juvenile / Q000473:pathology*; D057205:Automation, Laboratory / Q000379:methods / Q000592:standards; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D021621:Imaging, Three-Dimensional / Q000379:methods* / Q000592:standards*; D008279:Magnetic Resonance Imaging / Q000379:methods* / Q000592:standards*; D008297:Male; D011237:Predictive Value of Tests; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013583:Synovial Membrane / Q000473:pathology*; D014955:Wrist Joint / Q000473:pathology