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Computer‐assisted navigation applied to fetal cardiac intervention
Author(s) -
Emery Stephen P.,
Kreutzer Jacqueline,
Sherman Frederick R.,
Fujimoto Kazuro L.,
Jaramaz Branislav,
Nikou Constantinos,
Tobita Kimimasa,
Keller Bradley B.
Publication year - 2007
Publication title -
the international journal of medical robotics and computer assisted surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 53
eISSN - 1478-596X
pISSN - 1478-5951
DOI - 10.1002/rcs.145
Subject(s) - medicine , conventional pci , fetus , ventricle , imaging phantom , cardiology , fetal position , fetal heart , aortic valve , ultrasound , nuclear medicine , radiology , pregnancy , myocardial infarction , biology , genetics
Background Prenatal cardiac interventions (PCI) for human fetal aortic valve (AoV) stenosis can reduce left ventricular hypoplasia and restore ventricular growth and function. However, ‘freehand’ needle delivery from the maternal skin through the uterine wall, fetal chest and ventricular apex to cross the fetal AoV remains technically challenging and time intensive, and is the rate‐limiting step in the procedure. Methods We developed a computer‐assisted navigation (CANav) system that tracks the position and orientation of a two‐dimensional (2D) ultrasound image relative to the trajectory of an electromagnetic (EM) embedded needle and stylet. We tested the CANav system in vitro using a water bath phantom, then in vivo using adult rats and pregnant (fetal) sheep. Results The CANav system accurately tracked the delivered needle position in both in vitro phantom and adult rat model experiments. We performed 22 PCI attempts with or without CANav in a fetal sheep model. Maternal laparotomy was required to adjust the fetal position in 50% of the procedures. The time required to deliver the needle from the skin into the left ventricle (LV) using CANav was 2.9 ± 1.7 (range 2–7) min ( n = 14) vs. 5.5 ± 4.3 (range 1–12) min ( n = 8) without CANav ( p < 0.05). The time needed to cross the aortic valve once the needle was within the LV was similar with and without CANav ( p = 0.19). Conclusions CANav reduces the PCI time required to accurately deliver a needle to the fetal heart. Adaptations of this technical approach may be relevant to other congenital cardiac conditions and ultrasound‐guided medical procedures. Copyright © 2007 John Wiley & Sons, Ltd.