LOCALIZED INVIVO HIGH-RESOLUTION NMR IMAGING USING GRADIENT SUBENCODING TECHNIQUE

A new spatial localization technique for in vivo high-resolution imaging is presented here. In contrast to other localization techniques that use a series of rf pulses to define a volume of interest, only one rf pulse is utilized in the proposed method for selection of a region to be imaged. Instead of rf pulses for region selection, subencoding gradient pulses are used for the localization together with a convolution process on each phase-encoding gradient by a set of additional gradients (e.g., y direction). Then the 2-D localization is completed by restricting the bandwidth in the readout direction (e.g., x direction). The latter is simply achieved by using a low-pass filter in the receiver system. By applying this technique on a human body, localized in vivo high-resolution images are obtained for the knee with much improved resolution. 100 x 100-mu-m in-plane (x,y plane) resolution images obtained from the human knee demonstrate that localized in vivo high-resolution imaging for both human and animals is possible with an in-plane resolution of below 100-mu-m.