Spinlocking for iMQCs

For iMQCs, the transformation into observable signal is in competition with decay from transverse relaxation, which significantly limits the maximum observed signal. Spinlocking slows that decay by trapping the transverse magnetization in place, but adding a spinlock pulse to an iMQC experiment requires a careful analysis of the physical mechanisms at work. We have explored the theory behind these sequences, and developed modifications to correctly implement spinlocking in an iMQC sequence.

One particular family of iMQCs, iZQCs (intermolecular Zero Quantum Coherences) have uncommon potential in magnetic resonance for both imaging and spectroscopy applications. However, previous in vivo work has been limited by loss of signal intensity due to T₂relaxation. The most significant mechanisms of in vivoT₂relaxation are spin exchange and motional inhomogeneity . In an attempt to alleviateT₂relaxation, the iZQC sequence is followed by the spin-locking pulse module (Figure 1).