Optical Fiber-Based MR-Compatible Sensors for Medical Applications: An Overview

Abstract

During last decades, Magnetic Resonance (MR)—compatible sensors based on different techniques have been developed due to growing demand for application in medicine. There are several technological solutions to design MR-compatible sensors, among them, the one based on optical fibers presents several attractive features. The high elasticity and small size allow designing miniaturized fiber optic sensors (FOS) with metrological characteristics (e.g., accuracy, sensitivity, zero drift, and frequency response) adequate for most common medical applications; the immunity from electromagnetic interference and the absence of electrical connection to the patient make FOS suitable to be used in high electromagnetic field and intrinsically safer than conventional technologies. These two features further heightened the potential role of FOS in medicine making them especially attractive for application in MRI. This paper provides an overview of MR-compatible FOS, focusing on the sensors employed for measuring physical parameters in medicine (i.e., temperature, force, torque, strain, and position). The working principles of the most promising FOS are reviewed in terms of their relevant advantages and disadvantages, together with their applications in medicine.

Review of diverse optical fibers used in biomedical research and clinical practice

“…5,[152][153][154][155][156][157][158][159] A biophotonic detection process can involve the sensing of a change in a physical parameter, such as the refractive index of a material or optical power loss due to fiber movement or microbending. For example, an optical fiber-based device can be utilized to sense perturbations in the evanescent field of the propagating modes in an optical fiber.…”

Fiber-optic sensors for monitoring patient physiological parameters: a review of applicable technologies and relevance to use during magnetic resonance imaging procedures

“…The applications in which FBGs serve solely as sensors cover many fields, 146 e.g., the monitoring of structural health, [147][148][149][150] operating conditions of electrical plants, [151][152][153] or life processes in the human body. [26][27][28][154][155][156][157][158] Furthermore, FBGs are popular for their resistance to modulations in the optical signal intensity, which is possible because of the so-called spectral encoding, i.e., the information is contained not in the light intensity but in a spectral parameter (wavelength). 159 This property, along with its socalled self-reference capability, i.e., a return to the referential values of spectral parameters after achieving the initial conditions, allow multiple Bragg gratings to be contained within one optical fiber.…”

“…19 Fiber-optic sensors [20][21][22] transmit signals using optical fibers, providing them with immunity to EM fields. Moreover, there are fiber-optic sensors 23 that are able to acquire a patient's physiological signals and subsequently extract the chosen parameters [24][25][26][27][28] if they are configured in an appropriate manner, i.e., connected with mechanical elements and placed near the patient.…”

Magnetic Resonance Sensors

“…A review of optical fiber sensors that are MRI compatible is presented in [6], focusing on the sensors employed for measuring physical parameters in medicine (i.e., temperature, force, torque, strain, and position) including working principles and their relevant advantages and disadvantages. This may, in the future see interesting combinations with other technologies such as with gated MRI modalities like the fetal electrocardiogram triggered MRI reported in [7].…”