Enhancing cervical sonography with methyl‐cellulose gel

Abstract

Purpose: Our purpose was to evaluate the performance of two different contrast agents for cervical sonography in obstetrical patients. In addition, we sought to evaluate this technique in a setting other than with transvaginal sonography, such as utilizing a transperineal or transabdominal approach.Methods: Women with an indication for cervical sonography without premature rupture of the membranes underwent placement of 10 mL of normal saline or water‐soluble methyl‐cellulose gel. Assessment of cervical dimensions and contour was performed via transperineal sonography prior to and after contrast placement. Two authors independently evaluated, the adequacy of visualization of the cervical canal, external os, and vaginal fornices. When an improvement in visualization after contrast placement was noted by both observers, the attribute was counted.Results: Twenty‐five patients were enrolled into two groups. The mean gestational age at examination was 26.6 ± 6.2 weeks in the saline group, and 27.5 ± 5.2 weeks in the methyl‐cellulose gel group, P = 0.58. Administration of contrast improved visualization in 18 women in the gel group vs. six in the saline group, P = 0.002. Seventeen patients in the gel group had easier identification of the external os and enhanced visualization of the fornices was noted in 13 patients (12 patients had both). The mean cervical length was similar prior to and after administration of contrast (gel 2.8 ± 0.9 vs. 2.9 ± 1.0 cm, P = 0.18, and saline 2.5 ± 0.9 vs. 2.6 ± 0.6 cm, P = 0.45). Intravaginal contrast did not alter the identification of funneling in either group.Conclusion: Intravaginal contrast allows for easier identification of cervical/vaginal anatomy in some patients undergoing ultrasonographic examination by transperineal scanning but did not significantly alter assessment of cervical length. Intravaginal soluble methyl‐cellulose gel is the superior cervical contrast agent to normal saline. This methodology may also be useful in other settings, such as with a transabdominal approach.