UAMS.EDU

Squid Array for Reproductive Assessment

SARA Project

In 1998 The University of Arkansas for Medical Sciences obtained a $3.7 million National Institutes of Health (NIH) grant to develop a new fetal assessment device using magnetoenceopalography (MEG) with SQUID (super conducting quantum interference device) technology. This device is now in use and is called SARA (Squid Array for Reproductive Assessment). The patient interface is large array, which covers the maternal abdomen from perineum to the top of the uterine fundus.

Beneath the surface of the array are 151 individual SQUID sensors. During depolarization of biological tissues, a weak magnetic field is generated perpendicular to the flow of this current. These sensors are capable of detecting minute-magnetic field fluctuations. MEG technology has been available for about 20 years using adult whole head instruments. We have modified this technology in order to assess the fetal neurological integrity.

 

Why It Is Important

  • There have been no new medical advances in the neurological assessment of the fetus in the antepartum period in over 20 years.
  • It is now known that most neurological damage occurs to the fetus prior to the onset of labor.
  • New adult neuroprotection technologies have been developed which may be capable of reducing the neurological damage during hypoxic insults. Attempts are being made to apply many of these biotechnologies to the newborn and fetus. Example: Head cooling of newborn infants.
  • Fetal MEG is a “High-Impact” research area. Future benefits are high in reduction of fetal morbidity and mortality. Risk is low, as we have demonstrated the feasibility of measurement techniques and signal analysis.
  • Any effective treatment capable of reducing fetal neurological damage in utero requires tests that can determine those fetuses who have suffered mild as well as severe damage.
  • There is currently no non-invasive test for fetal neurological status.
  • Functional MRI or PET can be used to image fetal brain activity, but are associated with risk from RF heating and ionizing radiation, respectively. Fetal movement dramatically interferes with these technologies.
  • Transabdominal fetal EEG is most likely not feasible, and application of EEG electrodes in utero is invasive.
  • Gaining experience measuring the evoked response in neonates does not address the need for a test of fetal neurological status, and does not directly add to our skills for fetal MEG recording.
  • Preliminary fMEG data from our pilot study have corroborated findings of Wakai and others, showing a fetal auditory evoked field (AEF) with a peak latency of approximately 200 ms.
  • Pilot data demonstrates our technical ability to separate fetal brain signals from the noise using available and proposed signal analysis techniques (signal averaging, filtering, and spatial filtering by adaptive beamforming).
  • Small array biomagnetometer systems already exist and have demonstrated limited usefulness in fetal MEG studies.
  • New instrumentation in a clinical setting is required for significant progress in evaluation of the fetal brain.
  • Imaging correlation is needed to help localize and interpret fetal and maternal magnetic signals.

What We Are Doing

1. Uterine Activity

  • Serial Studies – starting at 37 1/2 weeks
  • Induction of labor
  • Preterm labor
  • Labor at term

 2. Fetal Cardiac Assessment

  • Arrhythmias
  • Monitoring multiple gestation
  • Monitoring before, during and after drug treatment therapies

3. Fetal Neurological Assessment (Magnetoencephalography – MEG)

  • Auditory and visual evoked response
  • Spontaneous MEG
  • Fetal state assessment

4. Follow-up Newborn MEG/EEG studies

  • Auditory and visual evoked response
  • Combined spontaneous EEG and MEG