title: Micro-CT in the Assessment of Pediatric Renal Osteodystrophy by Bone Histomorphometry.
abstract: OBJECTIVE
  Computed tomography (CT) measurements can distinguish between cortical and trabecular bone density in vivo. High-resolution CTs assess both bone volume and density in the same compartment, thus potentially yielding information regarding bone mineralization as well. The relationship between bone histomorphometric parameters of skeletal mineralization and bone density from microcomputed tomography (μCT) measurements of bone cores from patients on dialysis has not been assessed.
  
  
  METHODS
  Bone cores from 68 patients with ESRD (age =13.9±0.5 years old; 50% men) and 14 controls (age =15.3±3.8 years old; 50% men) obtained as part of research protocols between 1983 and 2006 were analyzed by bone histomorphometry and μCT.
  
  
  RESULTS
  Bone histomorphometric diagnoses in the patients were normal to high bone turnover in 76%, adynamic bone in 13%, and osteomalacia in 11%. Bone formation rate did not correlate with any μCT determinations. Bone volume measurements were highly correlated between bone histomorphometry and μCT (bone volume/tissue volume between the two techniques: r=0.70; P<0.001, trabecular thickness and trabecular separation: r=0.71; P<0.001, and r=0.56; P<0.001, respectively). Osteoid accumulation as determined by bone histomorphometry correlated inversely with bone mineral density as assessed by μCT (osteoid thickness: r=-0.32; P=0.01 and osteoid volume: r=-0.28; P=0.05). By multivariable analysis, the combination of bone mineral density and bone volume (as assessed by μCT) along with parathyroid hormone and calcium levels accounted for 38% of the variability in osteoid volume (by histomorphometry).
  
  
  CONCLUSIONS
  Measures of bone volume can be accurately assessed with μCT. Bone mineral density is lower in patients with excessive osteoid accumulation and higher in patients with adynamic, well mineralized bone. Thus, bone mineralization may be accurately assessed by μCT of bone biopsy cores. Additional studies are warranted to define the value of high-resolution CT in the prediction of bone mineralization in vivo.
authors.affiliation: Department of Pediatrics, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California; and.
authors.forename: Renata C
authors.initials: RC
authors.lastname: Pereira
authors.affiliation: Department of Medicine, Veterans Affairs Sepulveda and David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California.
authors.forename: David S
authors.initials: DS
authors.lastname: Bischoff
authors.affiliation: Department of Medicine, Veterans Affairs Sepulveda and David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California.
authors.forename: Dean
authors.initials: D
authors.lastname: Yamaguchi
authors.affiliation: Department of Pediatrics, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California; and.
authors.forename: Isidro B
authors.initials: IB
authors.lastname: Salusky
authors.affiliation: Department of Pediatrics, David Geffen School of Medicine at the University of California, Los Angeles, Los Angeles, California; and kwesseling@mednet.ucla.edu.
authors.forename: Katherine
authors.initials: K
authors.lastname: Wesseling-Perry
mesh_terms: D000293:Adolescent; D000367:Age Factors; D015415:Biomarkers / Q000097:blood; D062005:Biopsy, Large-Core Needle; D015519:Bone Density; D016723:Bone Remodeling; D001842:Bone and Bones / Q000000981:diagnostic imaging* / Q000378:metabolism / Q000473:pathology*; D002118:Calcium / Q000097:blood; D016022:Case-Control Studies; D012080:Chronic Kidney Disease-Mineral and Bone Disorder / Q000097:blood / Q000000981:diagnostic imaging* / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D010281:Parathyroid Hormone / Q000097:blood; D011237:Predictive Value of Tests; D055114:X-Ray Microtomography
chemical_list: D015415:Biomarkers; C470125:PTH protein, human; D010281:Parathyroid Hormone; D002118:Calcium
keywords: bone biopsy; bone density; calcification, physiologic; child; humans; kidney failure, chronic; micro CT; renal dialysis; renal osteodystrophy