title: Unshielded fetal magnetocardiography system using two-dimensional gradiometers.
abstract: We developed a fetal magnetocardiography (fMCG) system that uses a pair of two-dimensional gradiometers to achieve high signal-to-noise ratio. The gradiometer, which is based on a low-Tc superconducting quantum interference device, detects the gradient of a magnetic field in two orthogonal directions. Gradiometer position is easy to adjust by operating the gantry to drive the cryostat in both the swinging and axial directions. As a result, a fMCG waveform for 25 weeks' gestation was measured under an unshielded environment in real time. Moreover, the P and T waves for 25 and 34 weeks' gestation, respectively, were obtained by averaging. These results indicate that this two-dimensional gradiometer is one of the most promising techniques for measuring fetal heart rate and diagnosing fetal arrhythmia.
authors: Advanced Research Laboratory, Hitachi, Ltd., 1-280 Higashi-Koigakubo, Kokubunji, Tokyo 185-8601, Japan.
authors: Yusuke
authors: Y
authors: Seki
authors: Akihiko
authors: A
authors: Kandori
authors: Yukio
authors: Y
authors: Kumagai
authors: Mitsuru
authors: M
authors: Ohnuma
authors: Akihiko
authors: A
authors: Ishiyama
authors: Tetsuko
authors: T
authors: Ishii
authors: Yoshiyuki
authors: Y
authors: Nakamura
authors: Hitoshi
authors: H
authors: Horigome
authors: Toshio
authors: T
authors: Chiba
mesh_terms: D005260:Female; D005333:Fetus; D005865:Gestational Age; D006801:Humans; D053798:Magnetocardiography / Q000295:instrumentation* / Q000379:methods*; D011247:Pregnancy; D011262:Pregnancy Trimester, Second