A multi-purpose open-source triggering platform for magnetic resonance

• Published in: Journal of magnetic resonance (1997) 2014-10, Vol.247, p.15-21
• Main Authors: Ruytenberg, T., Webb, A.G., Beenakker, J.W.M.
• Format: Article
• Language: English
• Subjects: Acoustic Stimulation; Acoustic trigger; Algorithms; Arduino; Cardiac MRI; Devices; Electrocardiography; Female; Freeware; Heart - physiology; Humans; Magnetic resonance; Magnetic Resonance Imaging - methods; Male; Microcontrollers; Open-source; Oximetry; Platforms; Respiratory Mechanics; Scanners; Source code; Stethoscopes; Wireless Technology
• ISSN: 1090-7807; 1096-0856
• DOI: 10.1016/j.jmr.2014.08.009

[Display omitted] •An open source, Arduino based, multi-purpose trigger platform for MR systems has been developed.•Wireless communication demonstrated between hardware in scanner and PC outside scan room.•Its use as an acoustic cardiac triggering unit is described.•Functional cardiac images were obtained at 7T.•It yields a reliable trigger compared to conventional ECG. Many MR scans need to be synchronised with external events such as the cardiac or respiratory cycles. For common physiological functions commercial trigger equipment exists, but for more experimental inputs these are not available. This paper describes the design of a multi-purpose open-source trigger platform for MR systems. The heart of the system is an open-source Arduino Due microcontroller. This microcontroller samples an analogue input and digitally processes these data to determine the trigger. The output of the microcontroller is programmed to mimic a physiological signal which is fed into the electrocardiogram (ECG) or pulse oximeter port of MR scanner. The microcontroller is connected to a Bluetooth dongle that allows wireless monitoring and control outside the scanner room. This device can be programmed to generate a trigger based on various types of input. As one example, this paper describes how it can be used as an acoustic cardiac triggering unit. For this, a plastic stethoscope is connected to a microphone which is used as an input for the system. This test setup was used to acquire retrospectively-triggered cardiac scans in ten volunteers. Analysis showed that this platform produces a reliable trigger (>99% triggers are correct) with a small average 8ms variation between the exact trigger points.