The potential benefit of optical fiber sensors embedded into medical textiles for the continuous monitoring of patients for MRI is presented. We report a monitoring system based on the use of two novel non-intrusive optical sensing technologies designed to measure the elongation due to abdominal and thoracic motions during breathing. The developed system can successfully sense textile elongation between 0.1% and 5%, while maintaining the stretching properties of the textile substrates for a good comfort of the patient. The solution prototyped shows a high stability and good reproducibility. The sensors are coupled to a compact, real time and accurate monitoring system.