In vivo MR micro imaging with conventional radiofrequency coils cooled to 77 degrees K

Cryogenically cooled conventional surface coils are shown to provide signif icant signal-to-noise ratio (SNR) gains for MR micro imaging of tissue stru cture in vivo. Measurements are described which employ a simple, all-polyvi nyl chloride (PVC) vacuum dewar capable of maintaining a bath of liquid nit rogen around the coil, within 5 mm of the tissue to be imaged. Images:acqui red in vivo at 64 MHz with a 2-cm diameter copper coil cooled to 77 K demon strated a gain in SNR of approximately 2.7 +/- 0.3 relative to those obtain ed with the same coil at room temperature under otherwise identical conditi ons. This increase is consistent with the reduction in coil resistance and the minor contribution to overall resistance from the imaging object, The p erformance of the coil is illustrated with images from the human finger and rabbit eye and potential applications are discussed. (C) 2000 Wiley-Liss, Inc.