title: Monitoring change in volume of calcifications in juvenile idiopathic inflammatory myopathy: a pilot study using low dose computed tomography.
abstract: BACKGROUND
  Dystrophic calcifications may occur in patients with J uvenile Idiopathic Inflammatory Myopathy (JIIM) as well as other connective tissue and metabolic diseases, but a reliable method of measuring the volume of these calcifications has not been established. The purpose of this study is to determine the feasibility of low dose, limited slice, Computed Tomography (CT) to measure objectively in-situ calcification volumes in patients with JIIM over time.
  
  
  METHODS
  Ten JIIM patients (eight JDM, two Overlap) with calcifications were prospectively recruited over a 2-year period to undergo two limited, low dose, four-slice CT scans. Calculation of the volume of calcifications used a CT post processing workstation. Additional patient data included: Disease Activity Scores (DAS), Childhood Myositis Assessment Scale (CMAS), myositis specific antibodies (MSA), and the TNFα-308 promoter region A/G polymorphism. Statistical analysis utilized the Pearson correlation coefficient, the paired t-test and descriptive statistics.
  
  
  RESULTS
  Ten JIIM, mean age 14.54 ± 4.54 years, had a duration of untreated disease of 8.68 ± 5.65 months  MSA status: U1RNP (1), PM-Scl (1), Ro (1, 4 indeterminate), p155/140 (2), MJ (3), Mi-2 indeterminate (1), negative (3). 4/8 JDM (50%) were TNF-α-308 A+. Overall, the calcification volumes tended to decrease from the first to the second CT study by 0.5 cm3(from 2.79 ± 1.98 cm3to 2.29 ± 2.25 cm3). The average effective radiation dose was 0.007 ± 0.002, 0.010 ± 0.005, and 0.245 mSv for the upper extremity, lower extremity and chest, respectively (compared to a standard chest x-ray-- 0.02mSV effective dosage).
  
  
  CONCLUSIONS
  We conclude: 1) the limited low dose CT technique provides objective data about volume of the calcifications in JIIM; 2) measuring the volume of calcifications in an extremity is associated with minimal radiation exposure; 3) This method may be useful to evaluate the efficacy of therapies for JIIM dystrophic calcification.
authors.affiliation: Division of Pediatric Rheumatology, Children's Mercy Hospital , 2401 Gillham Road, Kansas City, Missouri, 64108-4619, USA.
authors.forename: Maria
authors.initials: M
authors.lastname: Ibarra
authors.affiliation: Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.|Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Cynthia
authors.initials: C
authors.lastname: Rigsby
authors.affiliation: Cure JM Center of Excellence, Stanley Manne Research Institute affiliated with Ann & Robert H. Lurie Children's Hospital of Chicago, 225 East Chicago Avenue, Box 212, Chicago, IL, 60611, USA.
authors.forename: Gabrielle A
authors.initials: GA
authors.lastname: Morgan
authors.affiliation: Department of Medical Imaging, Ann & Robert H. Lurie Children's Hospital of Chicago, Chicago, IL, USA.|Department of Radiology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA.
authors.forename: Christina L
authors.initials: CL
authors.lastname: Sammet
authors.affiliation: Joseph J. Zilber School of Public Health, University of Wisconsin, Milwaukee, WI, USA.
authors.forename: Chiang-Ching
authors.initials: CC
authors.lastname: Huang
authors.affiliation: Cure JM Center of Excellence, Stanley Manne Research Institute affiliated with Ann & Robert H. Lurie Children's Hospital of Chicago, 225 East Chicago Avenue, Box 212, Chicago, IL, 60611, USA.
authors.forename: Dong
authors.initials: D
authors.lastname: Xu
authors.affiliation: The Department of Internal Medicine, The University of Oklahoma, Norman, OK, USA.
authors.forename: Ira N
authors.initials: IN
authors.lastname: Targoff
authors.affiliation: Cure JM Center of Excellence, Stanley Manne Research Institute affiliated with Ann & Robert H. Lurie Children's Hospital of Chicago, 225 East Chicago Avenue, Box 212, Chicago, IL, 60611, USA. pachman@northwestern.edu.
authors.forename: Lauren M
authors.initials: LM
authors.lastname: Pachman
mesh_terms: D000293:Adolescent; D002114:Calcinosis / Q000000981:diagnostic imaging* / Q000473:pathology; D002648:Child; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D009220:Myositis / Q000000981:diagnostic imaging* / Q000473:pathology; D010865:Pilot Projects; D011829:Radiation Dosage; D014057:Tomography, X-Ray Computed / Q000379:methods; D055815:Young Adult
keywords: Calcification; Calcification volume; Computed Tomography (CT); Juvenile idiopathic inflammatory myopathy; Overlap syndrome