SYSTEMS AND METHODS FOR CELL MEASUREMENT UTILIZING ULTRASHORT T2* RELAXOMETRY

摘要

The present disclosure is directed to a new technique for MR measurement of ultrashort T2 * relaxation utilizing spin-echo acquisition. The ultrashort T2 * relaxometry can be used for the quantification of highly concentrated iron labeled cells in cell trafficking and therapy. In an exemplary embodiment, a signal is induced by a low flip angle RF pulse. Following excitation pulse, a gradient readout is applied to form an echo. The time between the RF pulse and the center of the gradient readout is defined as TE. In tissues with highly concentrated iron labeled cells, T2 * could be below 1 millisecond. Therefore, the signal can be decayed to a noise level with an echo time of a couple milliseconds. Because T2 * is much longer in SPIO labeled cells, the signal acquired by spin echo is much bigger than that from the gradient echo, thus avoiding the negative effects associated with the massive signal loss in the image. The ultrashort T2 * relaxation map can then by overlaid on the regular T2 * map to generate the final T2 * map of the field of view.