Comparison of Histomorphometry and Computerized Tomography of the Spine in Quantitating Trabecular Bone in Renal Osteodystrophy

Abstract

Computerized tomography (CT) has the advantage of allowing the isolation of trabecular bone of the axial skeleton, which is the more sensitive to metabolic changes. By means of single-energy X-ray CT we have devised a method for assessing trabecular bone mass (TBM) at L-4 vertebral body, which has an acceptable reproductibility (CV = 2.76%). Normal values where obtained after studying 29 normal individuals from both sexes and different ages. In order to know if the method is accurate, TBM was assessed in 17 patients (6 with creatinine clearance < 6 ml/min and 11 on chronic hemodialysis), and in all of them the results were compared with the histomorphometry of the iliac crest bone biopsy. TBM assessed by CT correlated with trabecular bone volume (TBV; mineralized bone + osteoid) (r = 0.82; p < 0.001) and this correlation was not improved after adding the volume of marrow fibrosis to TBV. TBM assessed by CT also correlated with mineralized bone volume but at a lower level of significance (r = 0.72 ;p = 0.001), and no correlation was found with relative osteoid volume alone. These findings suggest that final CT value is an integral of mineralized bone and osteoid but with a higher influence of mineralized bone. Osteomalacia and osteitis fibrosa were seen in situations of normal, decreased, or increased TBM assessed by CT, although the 2 patients with severe osteosclerosis suffered osteomalacia. We conclude that the assessment of TBM by CT at the axial skeleton of uremic patients has an acceptable reproducibility and accuracy. Its potential role in the management of renal osteodystrophy by noninvasive means must be stablished with repetitive studies in the same subjects, as is suggested by preliminary reports.

Bone Mineral Density in Patients Beginning Hemodialysis Treatment

“…The same was stated by other authors [5]. Some say that renal osteodystrophy causes dramatic cortical demineralization [6], again others assert that the trabecular bone is more sensitive to metabolic changes [7,8]. Our own results show that the cortical bone is more sensitive.…”

A structural approach to the assessment of fracture risk in children and adolescents with chronic kidney disease

“…Renal osteodystrophy resulted in increased trabecular vBMD and markedly decreased cortical vBMD, whereas amenorrhea or glucocorticoid therapy resulted in the expected reductions in trabecular vBMD. Spine QCT data in CKD confirmed biopsy histomorphometric data: trabecular vBMD was increased in highturnover disease (+1.6 SD) and decreased in low-turnover disease (−1.2 SD) relative to age-matched controls [55]. A recent pQCT study in 12 adult transplant recipients demonstrated a significantly greater endosteal circumference and lower cortical thickness compared with controls [56].…”

Monitoring of Bone Mineral Content in Patients on Regular Hemodialysis

“…They therefore measured predominantly cortical bone [2][3][4][5][6][7], while mesurements at the spine merely reflect trabecular bone status. We did so because it is believed that axial trabecu lar bone is more sensitive to metabolic changes [11,12]. Yet, it remains unestablished whether cortical ortrabecular axial bone contributed to the gain in BMC, observed in our study.…”