0930 High-field MRI for foetal post-mortem examination

While acknowledging that this particular subject invokes both funding and technological limitations, the broad concept and value warrant some discussion. On the funding side, requests to medical aid schemes for post-mortem foetal analysis, whether at chromosomal, tissue or whole body level usually meet with resistance or absolute rejection. This is unfortunate, particularly in the context of recurrent foetal loss. Funders will cite reasons for rejection that will range from the condition/circumstances not being prescribed by law as a minimum benefit for members of medical aid schemes, to the foetus not being a member of the scheme and therefore not eligible for coverage. The technological limitation in the context of MRI is that conventional machines involving MRI at 1.5T lack resolution under normal operating conditions and therefore provide little useful information, except perhaps some insight into structure of the brain and spinal cord. Technologically, progress has now been made using high-field MRI at 9.4T, making it possible to obtain almost histological grade resolution of foetal tissues. In a recent report published in the Lancet, researchers from the UK studied 18 foetuses comparing 1.5 and 9.4T scanners and then following up with invasive autopsy. High-field MRI yielded better spatial resolution, tissue contrast and image quality of all organ systems and detected all structural abnormalities that were detected on autopsy. In contrast, conventional MRI was not diagnostically useful in 78% of cases. Significantly, while the criterion for inclusion in the study was gestational age of <22 weeks, in fact the median gestation was 16 weeks and weight ranged from 5 – 400g! This is clearly an exciting avenue for further investigation but unlikely to be widely available until technology and funding make it an affordable option. Perhaps note should also be taken of the corollary which is that in the event of a funder or family opting for conventional MRI, the outcome is likely to be unhelpful in many if not most cases.

Read more:
Lancet 2009; 374: 476-75 and 2007; 369: 1471-80
J Obstet Gynecol Can 2007; 29: 560-67
J Perinatol 2006; 26: 224-9