Open‐source implementation of X‐nuclear sequences using the Pulseq framework

Abstract Purpose Create vendor‐neutral modular sequences for X‐nuclear acquisitions and build an X‐nuclear–enabled Pulseq interpreter for GE (GE HealthCare, Waukesha, WI) scanners. Methods We designed a modular 2D gradient echo spiral sequence to support several sequence formats and a modular metabolite‐specific 3D balanced steady‐state free precession sequence for hyperpolarized (HP) carbon‐13 ( 13 C) MRI. In addition, we developed a new Pulseq interpreter for GE scanners, named TOPPE MNS (TOPPE Multi‐Nuclear Spectroscopy), to implement X‐nuclear acquisitions capabilities. We evaluated TOPPE MNS and the modular sequences through phantom studies using phosphorus‐31 ( 31 P), hydrogen‐2 ( 2 H), and 13 C coils, and in vivo studies including a human brain deuterium metabolic imaging study at natural abundance, HP 13 C animal studies, and human renal studies. Results Data from the 13 C phantom showed the accuracy of designed modular sequences and consistent performance with the product sequences. 31 P, 2 H, and 13 C phantom studies and a multi‐vendor/multi‐version 13 C phantom study showed accurate excitation and spatial encoding functionalities. A 2 H‐MRS brain volunteer study, HP [1‐ 13 C]pyruvate animal study, and human renal study showed good image quality with SNR comparable to those reported in the published literature. These results demonstrated the reproducibility of the TOPPE MNS GE interpreter and modular spiral sequences. Conclusion We have designed a modular 2D gradient echo spiral sequence supporting several sequence formats and a modular metabolic‐specific 3D balanced steady‐state free precession sequence for 13 C acquisition, as well as developed a GE interpreter with X‐nucleus capabilities. Our work paves the way for future multi‐site studies with acquisitions for X‐nuclei across MRI vendors and software versions.