Enhancement of spectral editing efficacy of multiple quantum filters in in vivo proton magnetic resonance spectroscopy

► The role of the phase of the 2nd 90° pulse in multiple quantum filters was evaluated. ► Product operator and numerical methods were used in the theoretical analyses. ► The theory was experimentally validated with myo-inositol and glutamate editing. ► The phase of the pulse provides an additional spectral filtering mechanism. ► It is based on the degree of coupling beyond the level-of-coherence approach.