Image gating in MR canners using a fiber optic respiration monitor

The authors have previously developed a fiber optic based device for respiration measurement. We report here on the development of this device to act as a gating tool to allow for respiratory compensation in MR scanners. The principle of operation of the device is based on bending losses induced in coiled optical fibers which are located in an elasticated bandage that can be placed over the thoracic or abdominal regions. The system features a graphical interface written in Visual Basic for Windows. The system provides an optical feedback channel that permits the MR subject to inhale, exhale or hold their breath as required, in order to maintain the chest wall in the appropriate position. Results presented here indicate the utility of the technique in assisting a test subject to reproduce accurate breath holds.