Researchers at the OFSETH project have developed optical textiles to monitor MRI patients, especially those under anesthesia, during their scans. These wearable systems permit health professionals to watch patient heart rate, respiration, and other potential signs of patient distress. MRI machines usually obscure the patient visually and many new regulations prohibit medical staffers from remaining in the room while testing is in progress so monitoring from an external location is necessary.
|Children during anesthesia for MRI
of MRI exams under anesthesia
are currently performed
on children (Credit: Hopital Roger
Salengro/CHRU Lille – 2004)
Traditional medical monitors use metal parts and electronics that would interfere with the electromagnetic pulses generated by the MRI machine while it’s in use. Metal parts can also cause burning or other unpleasant or dangerous side effects when exposed to the MRI radiation. Optical monitoring will not interfere with the operation of the machine in any way nor will it cause any harm to the patient. In addition, any monitoring system must be portable and able to move with the patient as they move from the anesthesiologist to the machine table to the post-testing area where the patient remains until they wake up after their scan.
The OFSETH monitor uses silica and polymer optical fibers woven into an elastic bandage using standard commercial textile manufacturing processes. This bandage is wrapped around the chest and abdomen of patients. The material expands and contracts as the patient breathes, changing the intensity of light emitted by the fiber. This intensity can be monitored to reveal the breathing rate of the patient without any direct contact.
|It is difficult to see the patient in the MRI
bore, and even more to assess its well
being during anesthesia. Medical staff
can not stay near the patient, and have
to leave the room, where the anesthetized
patient stays alone. Monitoring has
therefore to be very reliable (Credit: Ofseth).
In addition, a finger tip sensor uses near infrared scattering to determine the blood oxygen levels of the patient. Like the bandage monitor, this sensor includes no metal or electrical parts that could interfere with the test or cause harm to the patient.
OFSETH, or the Optical Fibre Sensors Embedded into Technical Textile for Healthcare Monitoring program, is a consortium of researchers from eleven companies or organizations in five countries funded by the European Union. The researchers are split into three groups, one focused on the optics and sensors, one on the textiles, and one on the health elements of the project.
Prototype monitoring bandages are in limited use on adult volunteers at the Centre Hospitalier Regional Universitaire de Lille in Lille, France. The hospital is one of the members of the OFSETH consortium.
You can read more about the goals of the OFSETH group here
, the specific goals and requirements of the MRI monitoring system here
, a list of the OFSETH member groups can be found here
, and various reported results here