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).