Low-field MRI pelvimetry.

The purpose of this study was to evaluate the usefulness of low-field MRI pelvimetry and to correlate the results with X-ray pelvimetry. A total of 19 women underwent low-field MRI pelvimetry. Mediosagittal and transverse planes were used to measure the diameters of the minor pelvic cavity. Correlations between MRI and X-ray pelvimetry were 0.96 for the sagittal inlet, 0.94 for the sagittal outlet, 0.93 for the transverse diameter (diameter transversa, DT) and 0.94 for the bispinous distance (interspinous distance, IS). The repeatability of the measurements was good. For fetuses with cephalic presentation it was also possible to determine the biparietal diameter (BPD). Low-field MRI pelvimetry was well accepted by the patients. The scanning time was less than 6 min, which is comparable with the time of X-ray examination with two planes. Magnetic resonance imaging provides a reliable method to image pelvic structures and soft tissue without ionizing radiation.