[Pelvimetry using x-ray computed tomography]. / Pelvimétrie par tomodensitométrie.

The accuracy and the low radiation dosage administered when tomodensitometry is carried out for pelvimetry has led us to specify the use of this technique in every day practice. We propose to make is still more reliable and to simplify it. We have correlated the measurements obtained on the ultrasound screen with those that have been obtained by measuring the dried pelvis and have sought ways of measuring directly the three fundamental diameters of the pelvis. We have achieved exact measurements within one millimeter. This very precise correlation has been reproduced when we examined skeletons using the tomodensitometer. Then, when we checked again the accuracy of these measurements, we used the method on pregnant women. We have taken two views and two slices: an AP view to study the contents of the uterus and the morphology of the upper strait; a profile view to measure the diameter between the promontory of the sacrum and posterior surface of the symphysis, and we have programmed the two following slices: a perpendicular slice at the level of the upper strait measuring directly the transverse median diameter; another slice at the level of the sciatic spines to measure directly the diameter between these spines. We present this method because it is very simple and absolutely precise and gives all the information that is necessary. The patient does not have to stay still for long and only has a small dose of irradiation. This procedure does not need the use of conversion tables, nor parallel rulers nor standardisation.