The fast spiral-SelMQC technique for in vivo MR spectroscopic imaging of polyunsaturated fatty acids in human breast tissue.

The selective multiple-quantum coherence transfer method has been applied to image polyunsaturated fatty acids (PUFA) distributions in human breast tissues in vivo for cancer detection, with complete suppression of the unwanted lipid and water signals in a single scan. The Cartesian k-space mapping of PUFA in vivo using the selective multiple-quantum coherence transfer (Sel-MQC) chemical shift imaging (CSI) technique, however, requires excessive MR scan time. In this article, we report a fast Spiral-SelMQC sequence using a rapid spiral k-space sampling scheme. The Spiral-SelMQC images of PUFA distribution in human breast were acquired using two-interleaved spirals on a 3 T GE Signa magnetic resonance imaging scanner. Approximately 160-fold reduction of acquisition time was observed as compared with the corresponding selective multiple-quantum coherence transfer CSI method with an equivalent number of scans, permitting acquisition of high-resolution PUFA images in minutes. The reconstructed Spiral-SelMQC PUFA images of human breast tissues achieved a sub-millimeter resolution of 0.54 × 0.54 or 0.63 × 0.63 mm(2) /pixel for field of view = 14 or 16 cm, respectively. The Spiral-SelMQC parameters for PUFA detection were optimized in 2D selective multiple-quantum coherence transfer experiments to suppress monounsaturated fatty acids and other lipid signals. The fast in vivo Spiral-SelMQC imaging method will be applied to study human breast cancer and other human diseases in extracranial organs.