Development of a technique for postmortem CT angiography of fetuses with a lipophilic contrast agent

Background and objectives

Postmortem examinations of fetuses play a crucial role in confirming abnormalities, especially vascular and cardiac malformations leading to fetal demise. This study aims at developing and assessing a method for acquiring Post-Mortem CT-Angiography (PMCTA) with the injection of a lipophilic contrast agent (CA) to better visualize the great vessels of the trunk and head.

Materials and methods

25 human fetuses (gestational age at death between 106 days and 28 weeks) were included. Examinations were performed using a dual-energy Multidetector Computed Tomography (MDCT) scanner. Three imaging sequences were acquired, before CA injection, after injection of 7mL of CA through umbilical artery (arterial phase), and after an injection of 15mL of CA through umbilical vein (venous phase). CA-induced vascular opacification was scored per-vessel in both phases as follows: 0 = none, 1 = partial, 2 = complete. Total opacification was defined as the sum of the per-vessel opacification scores.

Results

In 23/25 subjects, CA injection into the umbilical vessels was feasible manually using flexible catheters. After the first injection, at least a partial opacification of the arterial network was achieved in 15/23 (65%) subjects. After the second injection, a complete opacification of the venous network was achieved in 18/23 (78%) subjects. Failures occurred in 10/25 (40%) subjects and were mostly due to the preservation status.

Conclusion

PMCTA performed with a two-phase intra-umbilical injection of a lipophilic CA enabled to visualize the vascular network, even after a significant a postmortem interval. This protocol may help in detecting vascular malformations, improving clinical diagnoses and prenatal counselling.