Dual gate ultrasonic backscatter technique compared to x-ray microtomography parameters

Abstract

Over 52 million Americans suffer low bone mass and at least 10 million suffer from osteoporosis. This study seeks to develop a dual gate ultrasonic technique for predicting bone quality as well as bone quantity. Ultrasonic pulses from a 5 MHz transducer were propagated into regions of porous bone in 18 bone specimens from one bovine and four human donors. The dual gate technique considered the normalized mean of the backscatter difference (nMBD), which is the power difference between two gated regions of 2 μs each placed 1 μs apart over the returned signal. This ultrasonic parameter was compared to eight X-Ray MicroCT parameters describing bone quality and quantity. Among these are the Structural Model Index (SMI) and Relative Bone Volume (BV/TV). SMI grades the structure of a specimen based on its plate and rod characteristics, making it a bone quality characteristic. SMI produced an R value of 0.982 with nMBD. BV/TV, a bone quantity indicator, finds the ratio of bone volume in the total specimen volume, and showed an R value of 0.993 with nMBD.