Association of QCT bone mineral density and bone structure with vertebral fractures in patients with multiple myeloma

JAN BORGGREFE; SARAH GIRAVENT; FELIX THOMSEN; JAIME PEÑA; GRAEME CAMPBELL; A. WULFF; A. GÜNTHER; MARTIN HELLER; CLAUS-C. GLÜER

Journal of Bone and Mineral Research

Juliet E Compston

Año: 2014

1523-4681

Purpose: Computed tomography is used for staging osteolytic lesions and detecting fractures in patients with multiple myeloma (MM). In the OLyMP-CT study we investigated whether patients with and without vertebral fractures demonstrate differences in bone mineral density (BMD) or microstructure which could be used to identify patients at risk for fracture.  Methods and Materials: We evaluated whole body CT scans in a group of 104 MM patients without visible osteolytic lesions using an underlying light weight calibration phantom (Image Analysis Phantom®). A QCT-software (StructuralInsight) was used for the assessment of bone mineral density (BMD) and bone structure of the T11 or T12 vertebral body. Age-adjusted standardized odds ratios (sOR) per standard deviation change were derived from logistic regression analyses, and areas under the curve (AUC) from receiver operating characteristics (ROC) analyses were calculated. Results: 46 of the 104 patients had prevalent vertebral fractures (24 of 60 men, 22 of 44 women). Patients with fractures were not significantly older than patients without fractures (64±9.2 vs 62±12.3 years, mean±SD, p=0.4). Trabecular BMD in patients with fractures versus without fractures was 169±41 vs 192±51 mg/cc, (AUC=0.62±.06, sOR=1.6(1.1-2.5), p=0.02). Microstructural variables achieved optimal discriminatory power at bone thresholds of 150 mg/cc. Best fracture disrimination for single microstructural variables was observed for trabecular separation (Tb.Sp) (AUC=0.72±.05, sOR=2.4(1.5-3.9), p<0.0001). In multivariate models AUCs improved to 0.77±.05 for BMD and Tb.Sp, and 0.79±.05 for Tb.Sp and trabecular thickness (Tb.Th). Compared to BMD values, these improvements of AUC values were statistically significant (p<0.0001). Conclusion: In MM patients, QCT-based analyses of bone structure derived from routine CT-scans permit discrimination of patients with and without vertebral fractures. Rarefication of the trabecular network due to plasmacell infiltration and osteoporosis can be measured. Deterioration of microstructural measures appear to be of value for vertebral fracture risk assessment and may indicate early stages of osteolytic processes not yet visible.