Evaluation of Magnetic Resonance Imaging Safety and Imaging Issues Associated with the Occlusion Balloon Used during Fetoscopic Endoluminal Tracheal Occlusion

Introduction: Congenital diaphragmatic hernias can be successfully treated by fetoscopic tracheal occlusion (FETO), a minimally invasive procedure that may improve postnatal survival. The endoluminal balloon utilized for FETO contains a metallic component that may pose possible risks for the fetus and mother related to the use of magnetic resonance imaging (MRI). The objective of this study is to evaluate MRI-related imaging and safety issues (magnetic field interactions, heating, and artifacts) for the occlusion balloon used in FETO.

Materials and methods: Using well-established techniques, tests were performed to assess magnetic field interactions (translational attraction and torque) and MRI-related heating and artifacts that occurred when exposing the occlusion balloon typically used for FETO (Goldbal2, Balt, www.balt.fr) to a 3-T magnet. MRI-related heating was determined by placing the occlusion balloon in a gelled-saline-filled, head-torso phantom and conducting MRI at relatively high, whole-body-averaged specific absorption rate (2.9 W/kg) for 15 min. Artifacts were measured in association with the use of T1-weighted, spin-echo and gradient-echo pulse sequences.

Results: The balloon displayed minor magnetic field interactions and physiologically inconsequential heating (highest temperature rise: 0.1°C above background). Artifacts extended approximately 10 mm from the occlusion balloon on the gradient-echo pulse sequence, suggesting that anatomy located at a position greater than this distance may be visualized on MRI.

Discussion: In this paper, we demonstrate that the risks of performing MRI at 3 T or less in a patient who has this occlusion balloon in place are acceptable (or MR conditional, using current terminology).