Utility of Multiplanar and Three-Dimensional Reconstructions From Computed Tomography Performed for Maternal Indications for Visualizing Fetal Anatomy and Estimating Gestational Age:

Transitional Female Sacrum: Dimensions, Alterations in Dorsal Pelvic Structure, and Potential Obstetric Implications

Objectives

The space available within the female pelvis is determined by the morphology of all bony components constituting the pelvic skeleton. Although several studies have investigated the impact of hip-bone structural variations in on parturition, the potential effects of commonly occurring lumbosacral transitional vertebrae (LSTV) variations have been underreported. This descriptive morphometric study reports dimensions of the female sacrum associated LSTV variations and suggests their probable mechanistic effects on normal labor.

Methods

One hundred and twelve female osteological sacral specimens with LSTV were examined for the type of transitional anomaly. Position, height, and surface areas of the auricular surfaces, interauricular distances, sacral heights, S1 body width and upper surface areas, and articulating areas of S1 facets were measured and compared with data from non-transitional samples.

Results

Female LSTV predominantly presented as accessory L5-S1 articulations (unilateral and bilateral) and degrees of lumbarization (separation of the first sacral segment). Since some of these alterations were found to be significantly associated with changes in sacral size, these features, in conjunction with cranial shift of the auricular surfaces, may be associated with overall in dorsal pelvic dimensions.

Conclusions

Structural alterations identified in female LSTV sacrum may change dorsal pelvic dimensions and thus, the availability of dorsal pelvic space, potentially altering the biomechanics of normal labor.

Normal Fetal Long Bone Length from Computed Tomography: Potential Value in the Prenatal Evaluation of Skeletal Dysplasias

BACKGROUND

The prenatal evaluation of skeletal dysplasias is challenging. Ultrasound (US) has limited sensitivity in evaluating these abnormalities. Low-dose fetal computed tomography (CT) is a helpful adjunct in evaluating the fetus with severe abnormalities, but its use is limited by lack of data on normal fetal bone length.

OBJECTIVE

To obtain CT measurements of fetal long bones and to compare published US normative bone length measures to examine their similarity.

METHODS

A retrospective search of a radiographic database for gravid patients with CT of the abdomen/pelvis for acute maternal abdomen was performed. Fetal long bone measurements were plotted against gestational age (GA)/standard US measurements. Regression coefficients were calculated (p values <0.05 were considered significant). Bland-Altman plots were constructed to identify any systematic difference between CT and US bone length measures.

RESULTS

Twenty-five cases met the inclusion criterion of fetal GA 16-39 weeks. The length of long bones increased with GA, with strong R2 values for each measurement. Plots of CT measurements against published 50th percentile sonographic values for age also showed strong and significant correlations, suggesting that values may be used interchangeably, a conclusion further substantiated by the Bland-Altman analyses.

CONCLUSION

A CT database for fetal long bone length is presented which can be used to evaluate the fetus with abnormal bones. Additionally we have established a strong correlation between measured fetal CT long bone values and the published 50th percentile normal values for US, which allows the interpreting radiologist to extrapolate CT measurements to US values in the evaluation of fetal bone length.

The value of post-mortem CT in neonaticide in case of severe decomposition: description of 12 cases

INTRODUCTION

In cases of neonaticide with delayed finding of the body, interpretation of autopsy results can be difficult because of decomposition. Postmortem computed tomography (PMCT) has become an increasingly popular tool in the (pediatric) forensic field. We performed a retrospective study to compare the outcome of PMCT with autopsy results in suspected neonaticide, in neonates found more than one week after their demise. We compared the performance of both methods on (1) determining gestational age, (2) differentiating between live birth and still birth and (3) determining cause of death.

METHOD

We selected all consecutive neonaticide cases with an estimated postmortem interval longer than one week, who underwent a forensic autopsy including a total body PMCT in the Netherlands Forensic Institute in the period 2008-2012. Both a pathologist and radiologist scored gestational age, signs of live birth and cause of death for each case.

RESULTS

22 cases of neonaticide were identified in the study period, of which 15 cases were estimated to be found more than 1 week after death. In 12 of these a total body PMCT was performed. In all cases, late postmortem changes were present. Gestational age could be assessed with PMCT in 100% of the cases and with autopsy in 58% of the cases. In all cases neither PMCT nor autopsy was able to assess live birth and cause of death.

CONCLUSION

PMCT is a better tool for estimating gestational age in case of suspected neonaticide with late postmortem changes compared to autopsy and should therefore be a standard part of the work-up. Signs of live birth and cause of death could not be determined with neither of the methods, an adjusted post mortem examination including limited autopsy for these cases might be developed.