Robust dual-angle T1 measurement in magnetization transfer spectroscopy by time-optimal control

Christina Graf, Rudolf Stollberger, Armin Rund, Martina Schweiger, Clemens Diwoky*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


Magnetization transfer spectroscopy relies heavily on the robust determination of (Formula presented.) relaxation times of nuclei participating in metabolic exchange. Challenges arise due to the use of surface RF coils for transmission (high (Formula presented.) variation) and the broad resonance band of most X nuclei. These challenges are particularly pronounced when fast (Formula presented.) mapping methods, such as the dual-angle method, are employed. Consequently, in this work, we develop resonance offset and (Formula presented.) robust excitation RF pulses for 31P magnetization transfer spectroscopy at 7T through ensemble-based time-optimal control. In our approach, we introduce a cost functional for designing robust pulses, incorporating the full Bloch equations as constraints, which are solved using symmetric operator splitting techniques. The optimal control design of the RF pulses developed demonstrates improved accuracy, desired phase properties, and reduced RF power when applied to dual-angle (Formula presented.) mapping, thereby improving the precision of exchange-rate measurements, as demonstrated in a preclinical in vivo study quantifying brain creatine kinase activity.

Original languageEnglish
JournalNMR in Biomedicine
Publication statusAccepted/In press - 2024


  • dual-angle
  • inhomogeneous fields
  • magnetization transfer spectroscopy
  • RF pulse design
  • time-optimal control

ASJC Scopus subject areas

  • Molecular Medicine
  • Radiology Nuclear Medicine and imaging
  • Spectroscopy


  • BioTechMed-Graz

Cite this