Postmortem fetal organ volumetry using magnetic resonance imaging and comparison to organ weights at conventional autopsy
Article first published online: 18 DEC 2007
Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.
Ultrasound in Obstetrics & Gynecology
Volume 31, Issue 2, pages 187–193, February 2008
How to Cite
Breeze, A. C. G., Gallagher, F. A., Lomas, D. J., Smith, G. C. S. and Lees, C. C. (2008), Postmortem fetal organ volumetry using magnetic resonance imaging and comparison to organ weights at conventional autopsy. Ultrasound Obstet Gynecol, 31: 187–193. doi: 10.1002/uog.5199
- Issue published online: 5 FEB 2008
- Article first published online: 18 DEC 2007
- Manuscript Accepted: 26 JUL 2007
- Members of the Cambridge Post-mortem MRI Study Group include: Dr Justin Cross, Dr Patricia Set, and Ilse Joubert of the Department of Radiology, Addenbrooke's Hospital; Dr Anita Whitehead and Dr Flora Jessop of the Department of Histopathology, Addenbrooke's Hospital, and Dr Gerald Hackett, Division of Maternal–Fetal Medicine, Addenbrooke's Hospital. We acknowledge the assistance of the pediatric pathology service staff of Addenbrooke's Hospital: N. Wood, G. Kenyon, S. Brown and M. Macer. This study was supported by a grant from the Trustees of the Addenbrooke's Charities and the Fund for Addenbrooke's. ACGB's salary was in part funded by Cambridge Fetal Care. Images were produced with the help of Richard Black, Medical Physics, Addenbrooke's Hospital, and statistical assistance was provided by Sarah Vowler of the Centre for Applied Medical Statistics, Cambridge.
- birth weight;
- cause of death;
- fetal death;
- fetal growth restriction;
- fetal organ maturity;
- lung volume measurement;
- magnetic resonance imaging;
- measurement studies;
- organ size;
- postmortem imaging;
- pulmonary hypoplasia;
- specific gravity
Following perinatal death, organ weights at autopsy may provide evidence of growth restriction and pulmonary hypoplasia. Whilst postmortem magnetic resonance imaging (MRI) may provide comparable information to autopsy about structural abnormalities, its ability to provide reproducible data about organ size has yet to be determined. We examined the feasibility of using postmortem MRI to provide estimates of organ size and weight.
Twenty-five fetuses of gestational age from 16 to 40 weeks underwent postmortem MRI prior to autopsy. Fetal lung, brain and liver volume estimations were performed by two observers using the stereology technique on postmortem MRI slices. Fetal lung, brain and liver weights were recorded at autopsy. Organ volume estimates and autopsy organ weights were compared using regression analysis, and estimates of fetal organ densities made. Interobserver variability was assessed using a Bland–Altman plot. Receiver–operating characteristics curve (ROC) analysis compared MRI brain : liver volume ratios to autopsy brain : liver weight ratios.
A linear relationship between organ volume estimates and organ weight was observed. Estimated densities for the fetal brain, liver and lung were 1.08 g/cm3, 1.15 g/cm3 and 1.15 g/cm3, respectively. Interobserver 5th and 95th percentile limits of agreement for fetal brain, liver and lung were − 5.4% to + 7.9%, − 11.8% to + 8.3% and − 14.3% to + 8.7%, respectively. For MRI organ volumes to detect a brain weight : liver weight ratio ≥ 4, ROC analysis demonstrated an area under the curve of 0.61, with an optimal cut-off of 4.1.
Postmortem MRI organ volumetry can be used to estimate weights of major fetal organs. This may increase the information obtained from a minimally-invasive perinatal autopsy, particularly in the context of pulmonary hypoplasia and intrauterine growth restriction, where differential organ growth plays a major part in assessment of the underlying pathology. Copyright © 2007 ISUOG. Published by John Wiley & Sons, Ltd.