['To determine the superior contrast agent for cervical sonography: water-soluble methylcellulose gel vs. normal saline.', 'Women with an indication for cervical sonography underwent placement of 10 mL water-soluble methylcellulose gel or normal saline. Assessment of cervical dimensions and contour was performed via transperineal sonography prior to and after contrast placement.', 'Twenty-five patients with similar demographic characteristics and indications for ultrasonography were enrolled into each group. Administration of contrast improved the ability to visualize the external os or vaginal fornices in 18 women in the gel group vs. six in the saline group (P = 0.002). In the gel group, 17 patients had easier identification of the external os and visualization of the fornices was enhanced in 13 patients. The assessment of cervical length prior to and after contrast administration was not statistically different with the use of either of these agents.'] Is methylcellulose gel a superior contrast agent for ultrasound examination of the cervix in obstetric patients?