Marie-Curie Fellow
Research & Training Network
I.K. Steinseifer (ESR)

Marie Curie Fellow (ESR) of the FAST project
Radboud University Nijmegen Medical Centre, Netherlands
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• T2 Acquisition
  Task 2 exploits the strong synergy between signal processing and MR methodology to reduce the MRSI acquisition-time. It shall use the latest technical developments and (confidential) expertise of our Industrial partners Philips and Siemens concerning high-speed gradients, coil arrays, novel pulse sequence designs for extending the limits of spatial resolution, temporal resolution, and SNR. T2 and T4 also investigate and develop advanced, innovative ways of acquiring MRSI data, at the forefront of MR-methodology. This is a highly challenging task exploring uncharted paths. Data of patients with brain, prostate and breast cancer, diabetes, etc., and of healthy controls will be acquired, co-registered and evaluated with MRI. High-Resolution Magic-Angle Spinning (HRMAS) NMR spectroscopy will provide additional chemical analysis of targeted tissues. Ideally, the feasibility of new concepts can be tested with the virtual scanner of task T3. Ultimately, T2 leads to ultra-fast MRSI. Philips and Siemens play an important role in this task.

• T6 Applications
  Task 6 judges and criticizes/approves FAST's innovations in preclinical and clinical settings. T6 also improves knowledge about diseases and metabolomics, gathered through MRSI. In essence, metabolomics pertains to identification of as many metabolites as possible and to understand each in its own biochemical context. MRSI can measure metabolite concentrations, chemical shifts, pH, etc. non-invasively and therefore has a huge potential for this task. Through time, much more emphasis will be placed on diagnosing and treating symptoms before secondary symptoms occur -- prevention rather than the cure of a (potential) disease. The role of Industrial partner Sanofi-Aventis is important in this task.

The main aim of my PhD work is to develop fast sequences, e.g. PEPSI, to minimize the acquisition time of MRS.These sequences will be applied in oncology, focused on prostate and brain cancer. Current projects:

1. Adaptation of a PEPSI sequence and adding of adiabatic pulses for the 7T scanner in Essen.

2. Chemical exchange saturation transfer (CEST) measurements of spermine in the prostate.

3. Fast Metabolic Imaging: This study describes a novel technique for fast metabolic imaging at 7T. Images of multiple metabolites can be obtained simultaneously by selective excitation of these resonances with a multi frequency selective Shinnar-LeRoux pulse. A proper choice of bandwidth of the 3D gradient echo imaging sequence allows to use the chemical shift displacement of the resonances to completely separate the images of different metabolites within one large field of view (FOV). The concept of fast metabolic imaging has been proofed by measuring 31P metabolites in human femoral muscle tissue. (Talk at the "ISMRM Benelux 2010", Publication in preparation)

4. Implementation of GOIA-W(16,4) pulse in SPECIAL sequence: In ¹H MRS the SPECIAL technique combines the advantages of ultra-short TE with full sensitivity obtained by SE based sequences. We present an adiabatic SPECIAL pulse sequence at 7T with two GOIA-W(16,4) pulses for refocusing. The GOIA-W(16,4) pulses provide a large bandwidth of 20 kHz and therefore make SPECIAL less sensitive to inhomogeneities and chemical-shift artefacts. We tested the SPECIAL-GOIA combination with a phantom and in vivo brain measurements. Even though TE is elongated by the implemented GOIA-W(16,4) pulses, it is still short enough to resolve coupled spin systems. We measured the same metabolites as with the original SPECIAL technique.

•  gradient acoustic safety of EPSI sequences at high field with D. Amariei (UAB, Barcelona) and with C. Labadie (ULeipzig)
• Implementation of GOIA-W(16,4) refocusing pulse in SPECIAL sequence with Ralf Mekle and Rolf Gruetter (EPFL, Lausanne)