Fetal MRI bests traditional-controversial-autopsies

August 18, 2009

When it comes to determining the cause of death for fetuses, parents may have another option besides conventional autopsy. Whole-body high-field MRI offers a reliable option for postmortem exams in a less invasive way, according to British researchers.

When it comes to determining the cause of death for fetuses, parents may have another option besides conventional autopsy. Whole-body high-field MRI offers a reliable option for postmortem exams in a less invasive way, according to British researchers.

Past scandals in the U.K. have reduced postmortem autopsy rates for fetuses. In 2001 it was reported that Alder Hey Children's hospital in Liverpool, U.K., had retained hearts and other organs from hundreds of children and fetuses who died at the hospital between 1988 and 1996. The hearts and organs were obtained without permission and used for research purposes.

MRI might be more appealing than traditional autopsy, according to Dr. Neil Sebire, a professor of pediatric and developmental pathology at the University College London's Institute of Child Health and an author of the current study.

After the 2001 scandal there was a sharp decline in consent for autopsies, presumably because parents feared organs might be kept, Sebire said.

Sebire, Dr. Sudhin Thayyil, and colleagues conducted whole-body MRI scans on 18 fetuses with less than 22 weeks' gestation and followed up with traditional autopsy (Lancet 2009;374:467-475).

The researchers compared MRI images at 9.4T and 1.5T. Traditional autopsy did not provide diagnostic accuracy superior to high-field MRI, and in some cases provided less information. In 13 cases, formal autopsy of the brain yielded no information; high-field MRI provided diagnostic information about the brain and spinal cord for half of the fetuses.

High-field MRI was better than conventional MRI in terms of spatial resolution, tissue contrast, and image quality for all organ systems. In addition, all structural abnormalities in the fetuses found with traditional autopsy were detected with high-field MRI. Conventional MRI found only 22% of the structural abnormalities.

The current study supports previous research showing conventional MRI has poor diagnostic usefulness in small fetuses, particularly for organs other than the brain.

In the future, pathologists might be able to offer a two-stage postmortem process to parents: a high-field MRI followed, if needed, by a targeted internal examination, Thayyil said. "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 postmortem research in the U.K.," Thayyil said.

The data, however, are preliminary, the researchers said. More evidence from large prospective studies is needed before whole-body high-field MRI can be offered as an alternative to traditional autopsy.