OBJECTIVE: To evaluate the uterine cervix length with magnetic resonance imaging in comparison with findings at transvaginal ultrasonography. MATERIALS AND METHODS: Twenty pregnant women between the 19th and 30th gestational weeks underwent magnetic resonance imaging and transvaginal ultrasonography for evaluation of their uterine cervix. Measurements by means of magnetic resonance imaging were performed by two specialists in imaging diagnosis for calculating the interobserver variability of the method. RESULTS: Calculation of the Pearson's correlation coefficient between measurements of the cervical length demonstrated a significant correlation between the results of both methods (r=0.628; p<0.01). The paired t test demonstrated no statistically significant difference between measurements obtained by transvaginal ultrasonography and magnetic resonance imaging (p=0.068). Interobserver agreement in cervical measurements by magnetic resonance imaging was high (a=0.96), demonstrating the reliability of the method. CONCLUSION: The comparison between both imaging methods in the evaluation of cervical biometry showed no statistically significant difference thus reinforcing the utilization of ultrasonography. However, in some cases where transvaginal ultrasonography is contraindicated, magnetic resonance imaging can be alternatively utilized for measurement of the cervical length.

Keywords: Uterine cervix, Pregnancy, Magnetic resonance imaging

Orthoradiographic measurement employing the "Farill technique" is a routine study in the majority of radiological services. For more than half a century, this method has been widely utilized by specialists in several areas for both measuring and treating differences in length between lower extremities. Nevertheless, technical procedural details during examination and measurements evaluation have usually been neglected or ignored, affecting the final results and consequently the effectiveness of this method. The present study is aimed at publicizing the details standardized by the authors, restoring accuracy to the technique, besides discussing it in comparison with other methods.

Keywords: Farill, Orthoradiographic measurement, Lower extremities, Difference