Reliability of quantitative elastography of the uterine cervix in at-term pregnancies

Aims: To evaluate the intra-operator reliability of tissue Doppler imaging-based quantitative cervical elastography in at-term pregnancies. Methods: Three series of two cycles of manual gentle compression-relaxation of the cervix were performed by one gynecologist in 11 consecutive at-term pregnancies through the vaginal probe. The compression movements should be sufficient to obtain the maximal compression of the anterior portion of the cervical tissue, until the posterior portion begins to be dislocated. Strain values were assessed on the entire thickness of the anterior cervical lip. The influence of strain type (Lagrangian vs. natural) and the extent of compression exerted (difference among the two cycles of compression-relaxation) were evaluated. Results: Strain measurement was influenced by the extent of compression, as well as by the strain type. The strain measured during the cycle with larger cervical compression, using the natural strain preset, showed a superior reliability [mean strain among patients: 0.68 +/- 0.18; mean of differences among three measures: 0.07 +/- 0.06; intraclass correlation coefficient (ICC) consistency: 0.90]. The strain measured using the Lagrangian strain preset showed overall a low reliability (ICC consistency: 0.04). Conclusions: Quantitative cervical elastography performed in at-term pregnancies, under standardized conditions, has a high reliability.