title: Nonfluoroscopic localization of an amagnetic catheter in a realistic torso phantom by magnetocardiographic and body surface potential mapping.
abstract: This study was performed to evaluate the accuracy of multichannel magnetocardiographic (MCG) and body surface potential mapping (BSPM) in localizing three-dimensionally the tip of an amagnetic catheter for electrophysiology without fluoroscopy. An amagnetic catheter (AC), specially designed to produce dipolar sources of different geometry without magnetic disturbances, was placed inside a physical thorax phantom at two different depths, 38 mm and 88 mm below the frontal surface of the phantom. Sixty-seven MCG and 123 BSPM signals generated by the 10 mA current stimuli fed into the catheter were then recorded in a magnetically shielded room. Non-invasive localization of the tip of the catheter was computed from measured MCG and BSPM data using an equivalent current dipole source in a phantom-specific boundary element torso model. The mean 3-dimensional error of the MCG localization at the closer level was 2 +/- 1 mm. The corresponding error calculated from the BSPM measurements was 4 +/- 1 mm. At the deeper level, the mean localization errors of MCG and BSPM were 7 +/- 4 mm and 10 +/- 2 mm, respectively. The results showed that MCG and BSPM localization of the tip of the AC is accurate and reproducible provided that the signal-to-noise ratio is sufficiently high. In our study, the MCG method was found to be more accurate than BSPM. This suggests that both methods could be developed towards a useful clinical tool for nonfluoroscopic 3-dimensional electroanatomical imaging during electrophysiological studies, thus minimizing radiation exposure to patients and operators.
authors.affiliation: Clinical Physiology-Biomagnetism Research Center, Catholic University, Rome, Italy. feniciri@rm.unicatt.it
authors.forename: R
authors.initials: R
authors.lastname: Fenici
authors.forename: K
authors.initials: K
authors.lastname: Pesola
authors.forename: M
authors.initials: M
authors.lastname: Mäkijärvi
authors.forename: J
authors.initials: J
authors.lastname: Nenonen
authors.forename: U
authors.initials: U
authors.lastname: Teener
authors.forename: P
authors.initials: P
authors.lastname: Fenici
authors.forename: T
authors.initials: T
authors.lastname: Katila
mesh_terms: D018780:Body Surface Potential Mapping; D006328:Cardiac Catheterization / Q000295:instrumentation*; D004562:Electrocardiography / Q000379:methods*; D004594:Electrophysiology; D006801:Humans; D008280:Magnetics; D019047:Phantoms, Imaging; D012815:Signal Processing, Computer-Assisted