Quantitative ultrasound imaging of the uterus for improved embryo implantation: preliminary study

Enhanced by the modern trend in postponing conception, infertility problems touch nowadays an increasing number of women. Many couples are therefore referred for in vitro fertilization procedures. Despite representing the most advanced option, in vitro fertilization still counts for a low success rate of about 30%. There is evidence that uterine movement may play an important role influencing the procedure outcome. Until now, no objective means of measuring uterine movement is available. Therefore, in this work we present the first method for quantitative analysis of the uterine movement. Given its widespread availability and relatively low cost, ultrasound imaging is employed for the analysis. In particular, a speckle-tracking algorithm has been implemented that is based on block matching by normalized cross correlation. Wiener deconvolution is used to regularize the image resolution prior to speckle tracking. The method feasibility was tested for its ability to distinguish between active and non-active phase of a natural menstrual cycle in eight women. Two pairs of sites were manually defined on the uterine muscle and automatically tracked over time. Variance and mean frequency of the strain and distance between these sites were the features extracted and evaluated for classification. The results are promising, showing significant class separation by Student t-test (p < 0.05), and sensitivity and specificity both equal to 75% for the strain variance and distance mean frequency. Extensive validation is however required to confirm this result, also involving the evaluation of additional features. Once fully validated, this method will be tested for quantitative evaluation of uterine movement in the context of in vitro fertilization.