SBIR-STTR Award

The search for non-invasive methods for determining fetal well-being in utero continues. Despite the introduction of electronic fetal heart rate monitoring, the overall rate of fetal hypoxia at birth has not decreased. The observed increase in the cesarean delivery rate since the introduction of continuous fetal monitoring is concerning. The goal of this project is to examine the accuracy of near infrared transabdominal fetal oximetry in determining fetal blood oxygenation, an important reflection of fetal well-being. The hope is to make a positive clinical impact on both improved neonatal outcome and reduction of the cesarean section rate. It is our proposal here to extend the penetration depth of safe and affordable NIR technology from the few cm for which significant results have been obtained in muscle, brain and breast to the depth (within the maternal abdomen) at which the fetal head is located for near term fetus. Obtaining this goal will enable us to quantify and image fetal brainoxygenation and blood volume for identifying fetuses at risk. A successful "Runman" type of dual wavelength spectrophotometer (tungsten lights, silicon diodes, with dichroic filters) has been improved to use a 10 cm source/detector separation to give blood volume and oxygenation trend signals from 30 pregnant mothers. These data have shown correlations of blood volume and oxygenation increase when the heart rate monitor has shown spontaneous increases of heart rate or when the startle reflex has been induced by a buzzer to activate the fetus. Three improvements of the device would provide localized signals from the fetal head; one, the use of three "Runman" type of sensors; two, a series of concentric circles of sources and detectors surrounding the abdomen; and three, multiple source/detector combinations (21 detectors and 9 dual wavelength sources) with an appropriate algorithm (initially back projection to image the head of the baby in utero) is proposed. The fetal head can further be distinguished from maternal signals by using the higher heart rate of the fetus. Here, phase locked loop technology will be used to track the fetal arterial pulse and to separate the fetal and maternal signals. The Phase I feasibility trials will be followed by Phase ll construction and test of the most appropriate instrument for in utero fetal oxygen monitoring.Proposed Commercial Application:In utero brain monitoring will open a new market for "preventive" medical devices that monitor the oxygen status of the fetal brain, immediately, noninvasively, safely and affordably. Obtaining additional information which will be used to determine whether less aggressive or more aggressive clinical intervention is required in order to prevent cerebral palsy and other brain damage occurrences will result in healthier children. The market can be expected to include both in-hospital and where necessary at-home monitoring and thus, may be expected to be a large fraction of the pregnant population.

Thesaurus Terms:
biomedical equipment development, brain visualization, clinical biomedical equipment, embryo /fetus monitoring, imaging /visualization, infrared spectrometry, oxyhemoglobin, prenatal diagnosis abdomen, embryo /fetus hypoxia, oximetry, phantom model, pregnancy bioengineering /biomedical engineering, clinical research, human pregnant subject

The phase-II application describes a systematic approach for the optimization and validation of trans-abdominal, near infrared (NIR) imaging of fetal cerebral blood saturation in utero. The phase-I accomplishments and additional preliminary investigations, demonstrate that it is possible to measure and quantify photon migration through the fetal head in utero, using continuous wave, NIR technology. The goal of the phase-II effort is to further optimize the NIR technology in order to enable quantitative, trans-abdominal, NIR imaging. First, a model based iterative image reconstruction (MOBIIR) scheme, will be adapted and optimized in conjunction with experimental and theoretical models for measurement geometries and data types, appropriate for trans-abdominal, NIR imaging. Next, two, complementary, dual wavelength, NIR devices will be optimized for trans-abdominal, NIR imaging. The first instrument will be a frequency domain device, with multiple source-detector pairs. The amplitude attenuation and phase delay in the tissue, measured with this device, will be incorporated in the MOBIIR scheme to quantify the blood saturation of the maternal and fetal tissues. The second instrument is a previously developed, continuous wave device. The amplitude modulation due to the fetal and maternal arterial pulses, measured with this device, will be incorporated into an algorithm based on pulse oximetry to extract the maternal and fetal arterial blood saturation. The accuracy and sensitivity of the two devices and corresponding analysis schemes will be validated using the near-term, pregnant ewe model. The feasibility of performing trans-abdominal, NIR imaging of fetal cerebral blood saturation in utero, will be evaluated in near-term patients. PROPOSED COMMERCIAL APPLICATION: Trans-abdominal, NIR imaging has the potential to assess fetal well being in near term, patients and patients during early labor (prior to descent of the fetal head). Fetal cerebral blood saturation obtained from trans- abdominal, NIR imaging in near-term patients or from patients in early labor can be used as an analog to scalp pH (which is generally obtained later in labor) to determine whether less aggressive or more aggressive clinical intervention is required. A low reading indicating fetal compromise could warrant the need for a cesarean delivery, while a normal reading could allow for the normal progression of labor. Trans- abdominal, NIR imaging may be particularly useful in early labor because during this period, the clinician may be confronted with non-reassuring fetal testing, but is unable to perform an NST, BPP (generally believed to be uninterpretable in labor), fetal scalp pH or internal monitoring (which requires cervical dilatation). Preventing the cesarean delivery of uncompromised fetuses (both premature and mature) in this manner, could have tremendous economic and medical benefits in the health care of children and mothers.