Abstract #4800

Open-Source, PNS-Constrained, and Optimized Gradient Waveform Design for Brain Diffusion Tensor Imaging

Ariel Hannum^1,2,3,4, Michael Loecher^1,2,3, Qingping Chen⁵, Eric Arbes⁵, Sebastian Littin⁵, Kawin Setsompop^1,6, Maxim Zaitsev⁵, and Daniel B Ennis^1,2,3

¹Department of Radiology, Stanford University, Stanford, CA, United States, ²Division of Radiology, Veterans Administration Health Care System, Palo Alto, CA, United States, ³Cardiovascular Institute, Stanford University, Stanford, CA, United States, ⁴Department of Bioengineering, Stanford University, Stanford, CA, United States, ⁵Division of Medical Physics, Department of Diagnostic and Interventional Radiology,, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany, ⁶Department of Electrical Engineering, Stanford University, Stanford, CA, United States

Synopsis

Keywords: Diffusion Acquisition, Pulse Sequence Design, Open-Source, Neuro Diffusion, High-Performance Gradients

Motivation: Gradient optimization approaches are an excellent strategy for DTI to manage competing constraints, particularly PNS on ultra-high-performance systems; however, vendor-specific implementations limit accessibility.

Goal(s): To integrate the open-source Gradient Optimization Toolbox (GrOpt) in Pulseq for brain DTI.

Approach: We implemented a 2x-accelerated, PNS constrained, single-shot EPI sequence in PyPulseq to include both GrOpt and conventional trapezoidal diffusion waveforms. The protocol was evaluated on commodity hardware and ultra-high-performance hardware.

Results: GrOpt-enabled sequences with PNS control demonstrated significant TE reductions compared to conventional waveforms. DTI metrics were validated across volunteers, with GrOpt consistently achieving higher SNR on both standard and ultra-high-performance MRI systems.

Impact: Integrating GrOpt into Pulseq enables efficient, SNR-enhanced diffusion encoding on ultra-high-performance MRI systems while managing peripheral nerve stimulation (PNS). This open-source solution makes advanced pulse sequence design accessible, thereby enabling DTI protocol consistency and utility across research settings.

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