A 32 Channel Receive-only Head Coil And Detunable Transmit Birdcage Coil For 7 Tesla Brain Imaging

This study extends the 32 channel soccer ball geometry previously described at 3T to 7T with a hybrid birdcage transmit coil and extended measures for reducing cable interactions and was evaluated in human imaging for SNR and g-factor performance.

Abstract

G. C. Wiggins, C. J. Wiggins, A. Potthast, V. Alagappan, O. Kraff, A. Reykowski, L. L. Wald Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, United States, Siemens Medical Solutions, Inc, Malvern, PA, United States, Department of Diagnostic and Interventional Radiology, University Hospital Essen, Essen, Germany, Invivo Corporation, Gainesville, FL, United States Introduction The phased array [1] provides a particularly attractive solution for MR imaging at 7 Tesla. Increases in tissue loading at high frequency favor the use of arrays with many small receiver coils, and accelerated parallel reconstruction techniques can decrease scan times and reduce susceptibility distortions. There are however many challenges in their design and use at fields of 7 Tesla and higher, including coil to coil and cable interactions. Since body transmit coils are not routinely available on 7 Tesla scanner systems, it is also necessary to incorporate a detunable transmit coil. While many favor gapped array designs with the aim of improving gfactor in SENSE acceleration, recent analysis suggests that for large numbers of coils (<16) the SNR which can be achieved with accelerated imaging techniques is higher for overlapped coil designs [2]. In this study we extend the 32 channel soccer ball geometry previously described at 3T [3] to 7T with a hybrid birdcage transmit coil and extended measures for reducing cable interactions. This device was designed to work inside a 36cm diameter head gradient coil. This prototype was evaluated in human imaging for SNR and g-factor performance. .