Trends in the use of pelvimetry techniques.
Assessment of maternal pelvic dimensions is usually considered necessary where vaginal delivery is contemplated in a breech presentation or if reduced pelvic dimensions are suspected in a current or previous pregnancy. Pelvimetry techniques include computed tomography (CT), conventional radiography, digital fluorography and magnetic resonance imaging (MRI). The first three techniques result in a radiation dose to mother and fetus which, depending on how the technique is performed, can vary by up to 40-fold. Of the techniques using X-rays, CT pelvimetry with a lateral scanogram generally gives the lowest radiation dose and conventional radiography using an air gap technique with a single lateral view is a relatively low-dose alternative where CT is not available. A questionnaire was sent to 227 hospitals during 1993 and 1996 to assess whether there was a move towards lower dose techniques of pelvimetry. The results show a trend away from conventional pelvimetry (48.4% in 1993 to 28% in 1996) with a small proportion of centres using MRI (4%) in 1996. Of the centres still using conventional pelvimetry, relatively few were using a low-dose air-gap technique (2.1% in 1993 to 10.9% in 1996). An increasing majority of centres were using one-view CT (69.3% in 1993 and 80.4% in 1996) but a significant proportion were still performing more than one view. This study shows that there was a move towards lower dose techniques of pelvimetry but that there were still many hospitals that had not implemented a policy of reducing radiation exposure in these patients.
Thomas
S M
SM
Department of Radiology, St George's Hospital, London, UK.
Bees
N R
NR
Adam
E J
EJ
D005260:Female; D019538:Health Care Surveys; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000706:statistics & numerical data; D010387:Pelvimetry / Q000379:methods / Q000706:statistics & numerical data* / Q000639:trends*; D010818:Practice Patterns, Physicians' / Q000639:trends*; D011247:Pregnancy; D011829:Radiation Dosage; D011856:Radiographic Image Enhancement; D014057:Tomography, X-Ray Computed / Q000379:methods / Q000706:statistics & numerical data; D006113:United Kingdom