Introduction
MR sequence design typically relies on vendor-specific toolkits, limiting flexibility and harmonization. Vendor-agnostic frameworks like Pulseq facilitate prototyping but require offline design with fixed parameters. Interactive alternatives like RTHawk exist but are closed source. We introduce Pulserver (https://github.com/INFN-MRI/pulserver), a Python client-server framework enabling interactive MR sequence design, available on GitHub and installable via pip and Docker.

Methods
Pulserver builds on Pulseq for accessibility but adds an abstraction layer to address Pulseq’s sequential block-based representation, which is unsuitable for low-latency interactive design. Our framework introduces Segments—ordered sets of Pulseq blocks representing periodic structures—and a dynamic Loop table containing adjustable sequence parameters. A Builder pattern allows efficient generation of Pulseq files while ensuring compatibility with the desired Pulseq interpreter.

To enable interactive design, we employ a TCP/IP client-server architecture. The scanner’s sequence process acts as a client, sending imaging parameters to a Python-based server, which returns the configured Sequence object. Our client supports Python 2/3 and integrates with vendor-specific Pulseq interpreters via a lightweight C library.

Validation
A 2D Gradient Echo phantom experiment on a GE Signa 7T scanner demonstrated interactive adjustment of imaging parameters with latency comparable to vendor-provided sequences, requiring no external hardware.

Conclusion
Pulserver bridges vendor-agnostic frameworks with interactive customization, facilitating rapid prototyping and clinical deployment.

Acknowledgements

This work was partially funded by the INFN-CSN5 PREDATOR project (“Grant Giovani”), NIH grant U24 NS120056, and the Italian Ministry of Health grant RC 2024 to IRCCS Fondazione Stella Maris.