Bone homogeneity factor: an advanced tool for the assessment of osteoporotic bone structure in high-resolution magnetic resonance images.

ABSTRACT

RATIONALE AND OBJECTIVES: Osteoporosis is characterized by low bone mass and inferior structural competence. In this study we introduce the bone homogeneity factor (BHF) as a quantitative measurement of bone structure, which could be equally important as bone mineral density. METHODS: BHF represents an advanced texture analysis tool based on the spatial autocorrelation function calculated in 9 different directions. These calculations were performed on high-resolution magnetic resonance images of the calcaneus at 3.0 T and compared with dual-energy x-ray absorptiometry measurements of the femoral neck. RESULTS: The quality and resolution of the high-resolution magnetic resonance images is sufficient for reliably calculating BHF. The mean BHF of the control group (n = 5, mean BHF = 525,0) with normal bone is significantly (P = 0.009, Mann-Whitney U test) higher than in the osteoporotic group (n = 7, mean BHF = 137,8). The BHF correlates with the DXA measurements of the femoral neck (correlation coefficient = 0.75). CONCLUSIONS: By calculating the BHF, it was possible to distinguish between osteoporotic and nonosteoporotic bone structure. Hence, BHF could be a possible candidate for noninvasive assessment of osteoporotic bone structure giving additional information to routinely used bone mineral densitometry.