An improved echo planar high-speed imaging technique using spiral scan is presented and experimental advantages are discussed. This proposed spiral-scan echo planar imaging (SEPI) technique employs two linearly increasing sinusoidal gradient fields, which results in a spiral trajectory in the spatial frequency domain (k-domain) that covers the entire frequency domain uniformly. The advantages of the method are: 1) circularly symmetric T2 weighting, resulting in a circularly symmetric point spread function in the image domain; 2) elimination of discontinuities in gradient waveforms which in turn will reduce initial transient as well as steady-state distortions; and 3) effective rapid spiral-scan from dc to high frequency in a continuous fashion, which ensures multiple pulsing with interlacing for further resolution improvement without T2 decay image degradation. Some preliminary experimental results will be presented and further possible improvements suggested.

A preliminary study of the correlation between acupuncture points (acupoints) for the treatment of eye disorders suggested by ancient Oriental literature and the corresponding brain localization for vision described by Western medicine was performed by using functional MRI (fMRI). The vision-related acupoint (VA1) is located in the lateral aspect of the foot, and when acupuncture stimulation is performed there, activation of occipital lobes is seen by fMRI. Stimulation of the eye by directly using light results in similar activation in the occipital lobes by fMRI. The experiment was conducted by using conventional checkerboard 8-Hz light-flash stimulation of the eye and observation of the time-course data. This was followed by stimulation of the VA1 by using the same time-course paradigm as visual light stimulation. Results obtained with 12 volunteers yielded very clean data and very close correlations between visual and acupuncture stimulation. We have also stimulated nonacupoints 2 to 5 cm away from the vision-related acupoints on the foot as a control, and activation in the occipital lobes was not observed. The results obtained demonstrate the correlation between activation of specific areas of brain cortices and corresponding acupoint stimulation predicted by ancient acupuncture literature.