Interleaved flow-sensitive dephasing (IFSD) for enhanced blood flow suppression and preserved T1-weighted contrast and overall signal intensity in 3D turbo spin-echo imaging

A method for interleaved flow-sensitive dephasing (FSD) in 3D turbo spin-echo (TSE), the method comprising:

• applying, via a sequence controller and through one or more radio-frequency coils, a 90-degree excitation radio-frequency pulse at a beginning of each time of repetition (TR);
• applying, via the sequence controller and through the one or more radio frequency coils, a 180-degree radio-frequency pulse only once per TR;
• applying, via the sequence controller and through the one or more gradient amplifiers, a pair of identical unipolar FSD gradient pulses symmetrically about the 180-degree radio-frequency pulse in both phase-encoding (denoted as y) and partition-encoding (denoted as z) axes to generate flow sensitivity along both axes (y and z), leading to net flow sensitivity along their sum vector;
• applying, via the sequence controller and through the one or more radio-frequency coils, a conventional 3D TSE refocusing radio-frequency pulse train and corresponding encoding and readout gradients to subsequently generate a series of spin echoes within the current TR;
• receiving radio-frequency signals by sampling individual spin echoes of the series of spin echoes;
• repeating the above steps in a next TR while toggling the polarity of the FSD gradient pulses along only one of the phase-encoding axis or the partition-encoding axis to generate flow sensitivity in a new direction orthogonal to that in the previous TR;
• and
• repeating the above steps, with the polarity toggled along the same axis, to achieve signal suppression of any flow in a two-dimensional space defined by the phase-encoding and partition-encoding axes while receiving all imaging data for final 3D image reconstruction,
• wherein flowing blood signals are suppressed while preserving tissue signal intensity and T1-weighted contrast because of the execution of short-duration FSD gradient pulses.