Spatial variability of shear wave speed estimation in the non-pregnant cervix

Shear wave speed (SWS) estimation is a noninvasive technique used to assess tissue properties. This could be a valuable tool in understanding changes that occur in the cervix during pregnancy and contribute to approaches for the prediction and prevention of preterm birth. The purpose of this study was to explore sources of biological variability in the normal non-pregnant cervix using shear wave speed estimation. Hysterectomy samples were collected (n = 22), a subset of which were ripened (n = 13). Multiple SWS measurements were made longitudinally along the cervical canal at 4-5 locations on both anterior and posterior halves of the cervix. Statistical tests were performed to determine significance of SWS as a function of position along the canal, anterior vs. posterior, ripened vs. unripened and variability among cervical samples using a linear mixed model. We found that SWS estimates monotonically increased from distal to proximal longitudinally along the cervix and varied anterior to posterior. All variables in the model were found to be significant (p<;0.05) using a likelihood ratio F-test to assess validity of fit.