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At least 19 recordsLinked to original sources

A comparative study of X-ray pelvimetry and CT pelvimetry.

In this study 24 patients who had conventional erect lateral X-ray pelvimetry had a CT pelvimetry done after delivery to complete the pelvimetry views. The erect lateral pelvimetry was read independently by a Consultant Radiologist, Consultant Obstetrician and a Medical Officer training in Obstetrics and Gynaecology. Using CT pelvimetry as the 'gold standard' (as the error of measurement was known with the machine used) the 3 readings were compared. There was no statistical difference in the values suggesting that X-ray pelvimetry is comparable to CT pelvimetry. However CT pelvimetry is preferred, if available, because of the lower dose of radiation involved, more comfort for the patient and shorter time in performing the procedure. Measurements done are easily read directly from the CT console.

Adolescent

Role of pelvimetry in active management of labour.

All cases referred for pelvimetry in 1970-1 and all breech presentations referred for pelvimetry in 1972-4 were reviewed. Indications for pelvimetry fell into four main categories: high head in the antenatal clinic (47-8%); high head in labour (13-9%); breech presentation (20-9%); and previous caesarean section (14-8%). In the first two categories pelvimetry rarely if ever influenced management, and it should not be performed routinely. In breech presentation and cases of caesarean section pelvimetry seemed to be of value, but in the latter group it should be performed puerperally to avoid the known radiation hazard to the fetus. A fairly close correlation between obstetric conjugate and pelvic capacity was shown, which suggested that a 3400-g baby might pass through a pelvis of obstetric conjugate of 10 cm as a cephalic trial of labour, but would need an obstetric conjugate of 11-7 cm for safe vaginal breech delivery.

Birth Weight

[Obstetric pelvimetry using nuclear magnetic resonance tomography (MRI): clinical experiences with 150 patients].

Between Oct. 1987 and Oct. 1991 150 patients of the Frauenklinik Freiburg were examined by MR pelvimetry (MRI), 135 of which were "ante partum", i.e. just before delivery. The indications were: earlier operative or strongly protracted delivery, clinical suspicion of disproportion between head and pelvis, or obstetrical "problem pelvis" indicated by manual pelvic examination or ultrasonic foetometry. Previous experimental measurements with a phantom and the comparison with conventional radiograms by Guthmann and Martius of 10 patients in puerperium have shown, that the mean divergence was +/- 2 mm, the maximum divergence 5 mm. The MRI method for pelvimetry "ante partum" or in childbed, proved to be a method of high accuracy and a very good option to judge the pelvic shape, whilst being well accepted by the patients. Furthermore, it allows to determine the foetal BIP (biparietal head-diameter), to judge the pelvic soft-tissue, as well as the visualisation of the birth canal, all without any exposure to radiation. MR pelvimetry is thus part of today's clinical routine. The disadvantages are still the high costs as well as the fact, that only few centres have access to MRI equipment. Nevertheless, the pelvimetry "post partum" can be safely practised radiologically due to the very low radiation exposure.

Female

The utilization and efficacy of pelvimetry.

Data from non random groups of deliveries with some identical clinical factors were compared and certain conclusions are suggested. Most x-ray examinations which cause significant fetal exposure are pelvimetries. There appears to be no uniform set of indications for performing pelvimetry. Instead, the criteria seem to vary from hospital to hospital and even from physician to physician within the same hospital. A normal pelvimetry gives the physicina little confidence that a cesarean section will not be necessary. The duration of labor is not significantly altered by pelvimetry in those cases needing a cesarean section for cephalopelvic disproportion or following unsuccessful oxytocin stimulation.

Cesarean Section

MR pelvimetry--a practical alternative.

Pelvimetry remains a useful technique as part of the assessment of the term breech pregnancy where vaginal delivery is planned. MR pelvimetry is accurate, well tolerated and shows soft-tissue structures as well as bone. It avoids the potentially carcinogenic effects of ionising radiation and is thought to be completely safe for mother and fetus. A technique of MR pelvimetry is described which uses gradient-echo sequences. This quick, practical method makes minimal inroads into valuable scanning time, and may therefore be considered a potentially cost-effective alternative to conventional pelvimetry.

Adolescent

[A technic of magnetic resonance tomographic pelvimetry in obstetrics].

Magnetic resonance imaging (MRL) allows for the first time direct determination of maternal pelvic dimensions without ionising radiation. Phantom measurements and the correlation with traditional pelvimetric measurements in 10 patients after Caesarean section have shown mean differences of +/- 2 mm, with a maximum of 5 mm. The evaluation of pelvic configuration is obtained analogous to the conventional roentgenogram. In addition to conventional or digital x-ray pelvimetry, the soft tissues of the maternal pelvis and the presenting part of the foetus is delineated with high contrast. Positioning in the body coil can be accomplished even late in pregnancy or in impending labour, acceptance by the pregnant women being high. Whereas in a given indication after delivery conventional x-ray pelvimetry continues to be performed, antenatally MRI pelvimetry has now been established in our Departments as the method of choice--based on meanwhile 107 examinations. Present drawbacks are the relatively high cost and the limited availability of MR units.

Evaluation Studies as Topic

The role of postnatal x-ray pelvimetry after caesarean section in the management of subsequent delivery.

The purpose of this study was to investigate the influence of postnatal x-ray pelvimetry after caesarean section on the management of the subsequent pregnancy. The case records of 331 women delivered by casearean section in their first pregnancy were reviewed. By standard radiological criteria, the pelvis was considered to be inadequate in 248 (75%) of them and adequate in 83 (25%). Of the women with a radiologically inadequate pelvis, 172 underwent an elective caesarean section. Seventy-six were allowed vaginal delivery: 51 of these women delivered vaginally and 25 required an emergency caesarean section. Of the women with a radiologically adequate pelvis, 61 achieved a vaginal delivery and 22 were delivered by caesarean section. All of the three cases of uterine rupture occurred in women with a radiologically adequate pelvis. This study suggests that x-ray pelvimetry is not a good predictor of the outcome of a trial of vaginal delivery. We conclude that the practice of routine postnatal pelvimetry should be abandoned.

Birth Weight

CT pelvimetry: the foveae are not an accurate landmark for the level of the ischial spines.

The most important distance measured during CT pelvimetry is the interspinous diameter of the pelvis as seen on axial scans, because most cases of obstructed labor occur at the level of the ischial spines. As the spines are difficult to identify on the anteroposterior digital scout radiograph, the fovea of the femoral head has been used as a landmark to determine the level of the appropriate axial slice. We assessed the accuracy of this landmark on CT scans in 23 women undergoing CT pelvimetry and in 20 nonpregnant women having pelvic CT scans. In each case the relationship between the level of the foveae and the level of the ischial spines was determined. True interspinous distances were measured and compared with the apparent interspinous distances at the level of the foveae. In none of the women were the ischial spines above the foveae. In 15 (65%) of 23 pregnant women and in seven (35%) of 20 nonpregnant women, the ischial spines were below the foveae. An incorrect scanning level led to an overestimation of interspinous distance by an average of 1.0 cm. We conclude that for CT pelvimetry, the fovea as seen on the anteroposterior digital radiograph is an inaccurate landmark for the level of the ischial spines.

Breech Presentation

[Obstetrical prognosis by x-ray pelvimetry].

For a period of 44 months 87 deliveries were analyzed by roentgenological pelvimetry, performed by a method, improved by the authors (1982). The relative part of pregnant women with roentgenological pelvimetry was 1.1%. Coefficients of obstetric prognosis were defined in groups retrospectively on the basis of a large material with roentgenological pelvimetry: "compatibility", "conditioned compatibility" and "noncompatibility" as a result of the ratio of the sum of pelvic diameters to the biparietal diameter of the fetus. In the group of "compatibility" of the fetus with the bony pelvis the women, who delivered operatively, had reduced pelvic dimensions with over 0.5 sm in vertex presentations and over 0.3 sm in breech presentations as well as larger weight of the fetus (respectively 4000 and 3500 g). The obstetric prognosis of the groups "compatibility" and "noncompatibility" was exact in 88.9% of the vertex presentations and in 81.5% of the breech presentations.

Birth Weight

[Pelvimetry].

It has been shown that, in all the different ways of performing pelvimetry, use of computed tomographic techniques leads to a significant reduction in radiation doses. We describe a new method of pelvimetry, involving computed tomography consisting of two scoutviews. The results of this method are compared with the results of conventional technique ad modum Fernström, measured in 55 women. Both methods showed large inter-observator differences. No statistically significant differences between the methods were revealed but the anteroposterior outlet was slightly smaller with the CT-technique (mean 6 mm). The method is recommended, since it is easy to use, and the rate of ionizing radiation is low.

Female

A prerecorded program for the Ball pelvimetry technique.

Pelvimetry can be simplified by a recently devised computer program. The program can be used with any of several advanced programmable pocket or desk-top calculators. This approach is more accurate than either the nomogram or the slide rule, and demands much less time and attention.

Computers

A computerized aid to Ball pelvimetry.

A computer program is presented that will generate a table of capacities and volumes for use with the Ball technique for cephalopelvimetry. The technique of Ball pelvimetry is reviewed and directions for use are described. This table may be produced on any medium or large-scale digital computer equipped with a FORTRAN compiler and a standard page printer. Its use eliminates many errors inherent in previous methods of volume computation. Physician acceptance has been excellent.

Cephalometry

Improving the accuracy of digital CT pelvimetry.

Digital pelvimetry is performed to assess the feasibility of vaginal breech delivery. This provides measurements of the anteroposterior inlet, transverse inlet, and interspinous distance. The transverse inlet measurement determined from an anteroposterior ScoutView can be inaccurate if its level is not at the gantry isocenter. Using a simple geometric argument, the theoretical error of this measurement is calculated and a method provided to allow for correction of this error.

Humans

[Pelvimetry (author's transl)].

A simple and precise technique for pelvimetry, delivering only a low dose of irradiation, is described. It includes the usual lateral view, but for the AP uses that of Fernstroëm. The technique and results are described.

Humans

[The prognostic importance of ultrasonic pelvimetry in anatomically contracted pelvis].

The lesser pelvis parameters measured by ultrasonic pelvimetry are characterized by different prognostic value for the functional assessment of various anatomic forms of contracted pelvis. Direct dimensions of the lesser pelvis, a difference of direct size of the orifice and fetal head biparietal size, and the pelviocranial index are prognostically the most valuable for patients with generally contracted pelvis. The same parameters are valuable for cases with Deventer's pelvis, and the sacrum flattening index value is also significant here. This latter characteristic is the only one prognostically valuable for cases with mesatipellic pelvis, permitting the prediction of possible labor complications.

Adult

Twenty degree angle modification for pelvimetry.

The standard Colcher-Sussman pelvimetry technique does not adequately visualize the interischial distance on a significant number of patients. A twenty-degree angulation modification has been developed to solve this problem.

Female

Radiation doses in low-dose pelvimetry using rare-earth screens.

A 'low-dose technique' of obstetric pelvimetry, using rare-earth screens and a reduced ambition level of image quality, yields an estimated absorbed dose to the maternal and foetal gonads of 0.9 and 0.01 mGy, respectively. The resulting risk for 'hereditary ill health' and the risk for induction of leukemia from the absorbed dose to the foetal red bone marrow, have been calculated to be at a very low level.

Female

Ultrasonic pelvimetry. A method for preliminary estimation of the pelvic outlet.

Vaginal sound, with transmitter crystals of 2 MHz, is used when measuring the interspinous diameter. The echo from pelvic wall, the effect on the measured spinal diameter by altering the position of the ultrasonic transmitter, and the influence of air or faeces between the ultrasound transmitter and the pelvic wall, have been analysed in a series of model trials on a dummy submerged in water. Thereafter clinical trials were performed on 102 women, pregnant in their 9th month. The results obtained when measuring the interspinous diameter on the ultrasonic tomogram were compared with the results obtained when measuring the same distance on a frontal x-ray picture taken using the orthographic technique according to Borell-Frenström. The method is suitable for selecting those cases with suspect constriction of the pelvic outlet for an x-ray examination by the Borell-Fernström technique.

Female