PELVIMETRY BY MEANS OF VARIOUS MRI TECHNI QUES VS DIGITAL IMAGE-ENHANCEMENT RADIOGRAPHY - ACCURACY, TIME REQUIREMENT AND ENERGY LOAD

In 50 patients with suspected or proven cephalo-pelvine disproportion pelvimetry was performed with MR-tomography using a gradient-echo-sequ ence (FLASH 2D) before or after labour. Results were compared with mea surements using digital radiography. In principle, both methods are ex changeable. The sagittal pelvic in- and outlet bispinous diameters are well reproducible. On the other hand, the transverse pelvic inlet and the distance between the ischiatic tubera are not so reliably reprodu ced. The accuracy of measurement does not depend on individual pelvic distances. Critical statistical analysis demonstrates, that in the wor st case differences between the two methods might become inacceptable. Our results indicate two major reasons: 1. there are interobserver pr oblems which cannot be neglected, and 2. the anatomical definition of referential landmarks for the measurements is unsafe. In 10 volunteers , a comparison was made between a T1-weighted spinecho sequence (SE), a fast gradient echo sequence (FLASH-2D) and an ultrafast gradient ech o technique (Turbo-FLASH). For the examination techniques presented he re, the high-frequency exposure load or specific absorption rate (SAR loc and SAR total) is below the values permitted by the German Federal Health Bureau (Bundesgesundheitsamt). Whereas the exposure load in ca se of spin-echo takes (SE) is 22fold higher than with the gradient ech o technique (GHE), the load values of ultra-fast GE (usGE) are only ab out 16% of the 2D-FLASH sequence or about 0.007% of SE. The difference in image quality does not affect the accuracy of measurement.