The purpose of the work is to develop an expandable catheter structure for deploying imaging coils inside the heart lumens for MRI-guided electrophysiological (EP) studies. Approximately 750,000 people are hospitalized each year in the US due to atrial fibrillation (AF) [1]. Intra-cardiac (IC) radiofrequency ablation (RFA) treatment is a catheter-based minimally invasive procedure in which abnormal tissue in the pulmonary veins is ablated to electrically inactivate the sites causing the irregular heart rhythm. Roadmaps for preoperative preparation and intraoperative catheter navigation can be provided by multi-parametric MRI (e.g. T2-weighted and Late Gadolinium Enhancement imaging). Through the use of an IC imaging coil, the ablated lesions can be observed in real time with excellent soft tissue contrast and lesion visualization, providing electrophysiologists better control over the result of the procedure. Invivo high element receive-coil arrays have shown accelerated imaging rates and enhanced image resolution [2]. This work integrates existing parallel MR imaging technology with a highly expanding origami mechanical catheter structure to achieve superior signal-to-noise ratio (SNR) IC MRI. This study presents a novel catheter instrument with unique origami deployable mechanisms for enabling intra-cardiac parallel MR imaging in MRI guided EP procedures.The ICMRI catheter deployable mechanism is modified from a previous catheter design [3]. The new deployable mechanism (Fig. 1a) contains multiple imaging coils to enable MR parallel imaging. The coils were directly printed onto the catheter structure and fabricated with a low-cost disposable design without the need of sterilization. The structure was developed by micro-fabricating a 60 mm x 60 mm piece of biocompatible polycaprolactone into an iso-area flasher origami pattern (Fig. 1b) , and contains an approximately 10:1 deployed to stowed ratio. Four imaging coils were constructed by printing square-shaped copper circuits in each corner of the structure. Tuning and matching coils (Fig. 2a) were mounted to the catheter structure, connected to the imaging coils, and wired to the proximal end of the catheter through micro-coaxial cables. The embedded circuit was tuned at 127.7 MHz (3T Larmor frequency) with -7.81 dB and matched to 50 ohm through the use of a network analyzer (Fig. 2b). As a result, the signal-to-noise ratio (SNR) was intensified at the resonant frequency of the MRI scanner, providing increased image resolution and soft tissue visualization. An optimal shape design was determined by evaluating the geometric components, the mechanical strength of the structure, along with the space necessary for storing tuning and matching electronics.High contrast image quality was obtained with the previous catheter design during ex-vivo swine left-ventricular (LV) and left-atrial (LA) imaging. A 2-4 times SNR increment in MR images was acquired using ICMRI versus Invivo array coils at distances of 5-8 cm from the coil, for both T1-w GRE and T2-w TSE. A 4-16 times faster imaging time was demonstrated with the ICMRI catheter, improving temporal efficiency.The ICMRI catheter increases image resolution and contrast visualization of soft tissue. The origami deployable catheter mechanism allows for a low-cost disposable design where multiple imaging coils could be directly printed on the catheter, potentially enhancing the imaging capabilities. The origami design could also be applied to other medical applications that involve expandable structures. In future work, the ICMRI catheter design for MR imaging and MR-guided EP procedures will be evaluated through in vivo studies in swine models.