Micro-CT in the Assessment of Pediatric Renal Osteodystrophy by Bone Histomorphometry.
BACKGROUND AND OBJECTIVES
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.


DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS
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.
['Pereira|Renata C|RC|', 'Bischoff|David S|DS|', 'Yamaguchi|Dean|D|', 'Salusky|Isidro B|IB|', 'Wesseling-Perry|Katherine|K|']
D000293:Adolescent D000367:Age Factors D015415:Biomarkers D062005:Biopsy, Large-Core Needle D015519:Bone Density D016723:Bone Remodeling D001842:Bone and Bones D002118:Calcium D016022:Case-Control Studies D012080:Chronic Kidney Disease-Mineral and Bone Disorder D005260:Female D006801:Humans D008297:Male D010281:Parathyroid Hormone D011237:Predictive Value of Tests D055114:X-Ray Microtomography
renal osteodystrophy bone density bone biopsy calcification, physiologic child humans kidney failure, chronic micro CT renal dialysis