Purpose or Case Report: The purpose of this study is to develop a method of training pediatric patients in effective breathing during magnetic resonance imaging (MRI).
Methods & Materials: An Arduino microcontroller was adapted to digitize pressure changes in a respiratory bellows and configured to wirelessly communicate with an iPad. An application was then developed for the iPad to display visually the breathing pattern. Through inspiration and expiration, the patient can control the displayed breathing waveform, with the goal following a sinusoidal path for regular breathing and a straight path for breath holding (Fig 1). An MRI-compatible video goggle system was adapted to enable mirroring of display of the iPad screen, thus enabling the patient is able to see his or her breathing pattern through video goggles during the exam. Pediatric subjects referred for MRI of the torso were recruited with informed consent. Respiratory information was recorded during an initial free-breathing sequence without visual feedback, and was subsequently recorded for an identical sequence with feedback. Waveforms were analyzed for regularity. A 3D radiofrequency spoiled gradient recalled echo T1 weighted fat suppressed sequence was adapted to provide three dimensional motion navigators to assess regularity of motion with and without feedback.
Results: Eight subjects were recruited, aged 7 to 24 years old. Although subjectively there was a broadening of the period and amplitude of respiration during visual feedback (Fig. 2), these metrics were not significantly different (p < 0.53 and p<0.9 respectively). Comparison of images with and without feedback demonstrated similar image quality (Fig. 3).
Conclusions: Real-time respiratory feedback is feasible but may not be effective in regularizing breathing pattern or improving image quality.