Time-resolved three-dimensional (3D) phase-contrast (PC) balanced steady-state free precession (bSSFP)

Area of Science:

• Medical Imaging
• Biophysics
• Fluid Dynamics

Background:

• Balanced steady-state free precession (bSSFP) sequences offer high signal-to-noise ratio (SNR) for fluid imaging.
• Accurate quantification of blood and cerebrospinal fluid (CSF) flow is crucial for diagnosing neurological conditions.

Purpose of the Study:

• To demonstrate the feasibility of a time-resolved, 3D, three-directional flow-sensitive bSSFP sequence.
• To adapt phase-contrast (PC) techniques for optimal flow velocity measurements.
• To address and mitigate common bSSFP artifacts for improved clinical utility.

Main Methods:

• Developed a custom algorithm for calculating optimal gradient parameters for phase-contrast (PC) flow sensitivity.
• Implemented artifact reduction strategies for eddy current distortion and flow-related steady-state disruption.
• Validated the sequence using a flow phantom and in vivo human studies of blood and CSF flow.

Main Results:

• The sequence accurately depicted blood flow in cerebral veins and CSF flow in the cervical spine.
• Successful mitigation of major bSSFP-related artifacts was achieved.
• High SNR in blood and CSF confirmed the sequence's effectiveness for flow velocity acquisition.

Conclusions:

• The developed flow-sensitive bSSFP sequence is feasible and effective for in vivo human studies.
• Potential applications include studying CSF flow patterns and pathologies like hydrocephalus and Chiari malformation.
• This technique may aid in validating existing CSF circulation models.