Whole-body high-field magnetic resonance imaging (MRI) is a reliable option for post-mortem examination of human fetuses and might provide a less invasive alternative to conventional autopsy, according to an Article published in this week's edition of the Lancet.
Examination after death can provide important information about why a fetus did not survive and help to assess the accuracy of diagnostic methods in utero and the risk to future pregnancies. This information is mainly obtained from autopsies. However, over the past decade—after incidents such as Alder Hey which raised public suspicion about autopsies—there has been a substantial decline in the number of parents agreeing to autopsy. This has prompted research into less invasive methods of post-mortem.
Conventional whole-body MRI at 1.5 T was thought to offer the most realistic alternative, but has been shown to provide inadequate image quality of small fetuses. In contrast, high-field (9.4 T) whole-body MRI provides good images and has shown promising results in small animals, but has not been performed in humans.
Sudhin Thayyil from UCL Institute of Child Health and Great Ormond Street Hospital and colleagues examined the feasibility of high-field MRI and compared the diagnostic usefulness of high-field MRI with conventional MRI and traditional invasive autopsy in small human fetuses.
Whole-body MRI at 9.4 T and 1.5 T was done on 18 fetuses of less than 22 weeks' gestation before doing a traditional invasive autopsy. Images from the MRI were compared with the findings of invasive autopsy in a blinded manner and assessed for diagnostic accuracy and image quality by a team of specialist paediatric radiologists.
Overall, traditional invasive autopsy did not provide superior diagnostic accuracy compared to high-field MRI in any of the examinations, and in some cases the high-field MRI provided more information than the invasive autopsy.
Spatial resolution, tissue contrast, and image quality for all organ systems were much better with high-field MRI than with conventional MRI. In addition, all structural abnormalities detected by traditional invasive autopsy and internal examination of visceral organs were also detected with high-field MRI. In contrast, conventional MRI was found not diagnostically useful in 78% of cases.
The authors say: "In the future specialist pathologists might be able to offer a two-stage post-mortem process to parents, whereby an MRI at 9.4 T plus information from all other non-invasive tests…is done first, and then, if needed, a targeted internal examination of the body is done (minimally invasive autopsy). Alternatively this form of autopsy might be offered to parents who refuse conventional autopsy…such an approach might increase the autopsy rates and bring back post-mortem research in the UK."
However, the authors caution that these are very preliminary data and further evidence from large prospective studies is required before minimally invasive autopsy can be offered routinely in clinical practice.
In an accompanying Comment, Elspeth Whitby from the University of Sheffield, UK, and Marta Cohen from Sheffield Children's Hospital, UK, highlight several practical problems that they say need to be addressed if post-mortem MRI is to have a significant role in the future. These include: limited access to MRI scanners, a service already stretched in the UK; and availability of specialist personnel to perform the scans and interpret the images when there is already a worldwide shortage of radiologists.
Jo Barber, Great Ormond Street Hospital/Institute of Child Health Press Office, London, UK. T) +44 (0)20 72393125 / +44 (0) 7710 262 264 E) barbej@gosh.nhs.uk
Dr Elspeth Whitby, University of Sheffield, UK. T) +44 (0)114 271 3584 E) e.whitby@sheffield.ac.uk
For full Article and Comment see: http://press.thelancet.com/postmortem.pdf
Journal
The Lancet