Comparison of three noninvasive methods for measuring scoliosis.

The premise behind most noninvasive techniques for the measurement of scoliotic conditions of the spine is that the lateral distortion of the spine relates directly to transverse rib cage deformity within the transverse plane. The focus of this study was to examine this assumption by comparing different noninvasive methods for the assessment of scoliotic curves. The three techniques examined were (1) use of the Scoliometer (SCOL), (2) use of the back-contour device (BCD), and (3) use of moiré topographic imaging (MTI). Fourteen subjects (10 female, 4 male) with idiopathic adolescent scoliosis were measured. Posterior-anterior radiographs were obtained for the clinical assessment of all subjects and were subsequently used to determine Cobb angles. Significant correlations between axial trunk rotation and Cobb-angle measurements were observed in the thoracic region (MTI, r = .80, df = 10, P less than .005; BCD, r = .70, df = 10, P less than .025; SCOL, r = .59, df = 10, P less than .025) but were not found within the lumbar region (MTI, r = .42; BCD, r = .17; SCOL, r = .20). Factors other than trunk deformity, such as the posture assumed by the subject during measurement, may have influenced axial trunk rotation. Hence, the techniques appear to provide valid estimations of lateral curvature of the spine in the thoracic region of the trunk but not the lumbar region. The results suggest that the measurement techniques cannot be used interchangeably in clinical recording.

An experimental study on biomechanical properties of hepatic tissue using a new measuring method.

Hepatic tissue is an important internal organ for life. In this paper, we combined the moire method (an optical method) and indentation technique to investigate biomechanical response of hepatic tissue. To examine this measuring technique, we first measured the biomechanical properties of the block of pig's hepatic tissue using this method. The experimental result indicated that the pig's hepatic tissue was obviously a viscoelastic material. We closely analyzed the change of curves for force relaxation, creep, and nonlinear deformation of the block of pig's liver. Meanwhile, we also compared the changes in the biomechanical parameters of normal and cirrhosis hepatic tissue of humans.