Lukas Hingerl, Bernhard Strasser, Philipp Moser, Michal Považan, Gilbert Hangel, Eva Heckova, Stephan Gruber, Siegfried Trattnig, Wolfgang Bogner

Proton magnetic resonance spectroscopic imaging is a powerful technique for clinical diagnosis; however, low spatial resolutions together with long scan times and SNR-per-time inefficiency prevent its wide spread application. The already proposed 2D-CONCEPT (concentric circle echo planar trajectories) sequence overcomes this issue by capitalizing most efficiently on the hardware constraints of the gradient system. The purpose of this abstract is to present first preliminary results of an extension to 3D-CONCEPT for full-brain 3D-FID-MRSI at 7T for a 64x64x31 matrix acquired within 23 minutes.

Sahar Nassirpour, Paul Chang, Anke Henning

In this work, we present high resolution whole-brain metabolite maps acquired at 9.4T for the first time. By combining a robust acceleration method with dynamic B₀ slice-wise shim updating, we achieved high quality metabolite maps from 10 slices of the brain with a nominal voxel size of ~80μL in ~25 minutes.

Dinesh Deelchand, James Joers, Edward Auerbach, Pierre-Gilles Henry

The goal of this study was to demonstrate the feasibility of prospective motion and shim correction for MRS at 7 Tesla. We combined an optical tracking system for motion correction and a shim navigator for first-order B₀ shim correction into a semi-LASER sequence. The new sequence was validated in the prefrontal cortex, a region sensitive to motion due to susceptibility effects induced by the proximity of the nasal cavity. Results show excellent performance, with similar spectral quality (signal-to-noise ratio and linewidth) before, during, and after motion when both motion and shim navigators are used.

Jane Ellis, Ladislav Valkovic, Lucian Purvis, William Clarke, Christopher Rodgers

Cardiac PCr/ATP ratios measured by ³¹P MRS change in cardiovascular disease giving them value as a biomarker. We scanned 13 healthy volunteers at 7T, assessing their PCr/ATP with 6 ½ min ³¹P CSI scans. These data have better reproducibility than a 30min 3T protocol previously published by our centre. Repeated PCr/ATP measurements from subjects in this study were not significantly (P=0.83) different. Measurements were significantly different (P<0.001) from DCM patient data acquired in a previous 7T study using the same coil and pulse sequence. This data will allow us to plan future 7T ³¹P-MRS clinical studies. 

Adil Bashir, Jianyi Zhang, Nouha Salibi, Ronald Beyers, Thomas Denney

Changes in Creatine Kinase (CK) system are observed in heart failure and measurement of CK reaction rate constant (kf) can be useful to monitor pathology. 7T MR scanner offers improved signal to noise and spectral resolution and has potential for robust measurements. In this study we demonstrate novel superfast saturation transfer method (T1nom – method) to measure ATP production rate via CK forward reaction in human hearts at 7T. Spatial localization was achieved by GOIA-1D-ISIS/2D-CSI approach. Our measured kf values were consistent with literature.

Quincy van Houtum, Dimitri Welting, Mark Gosselink, Christopher Rodgers, Wybe van der Kemp, Dennis Klomp

We combined 1H MRI and 31P MRSI in the liver by integrating a 31P RF body coil in a 7T MR system with a 16 channel 31P receive array merged with 1H fractionated dipole antennas The setup facilitates uniform 31P excitation by the body coil with high sensitivity from the receiver array, while providing B1 shimmed proton imaging with a dipole array. 

Fabian Niess, Albrecht Schmid, Georg Fiedler, Roberta Frass, Wolfgang Bogner, Alfredo Lopez Kolkovsky, Pierre Carlier, Ewald Moser, Martin Meyerspeer

To quantify perfusion and high-energy metabolite time courses of exercising gastrocnemius and soleus muscles in one time-resolved acquisition, ¹H arterial spin labeling with multislice EPI was interleaved with multivoxel semi-LASER ³¹P-MRS. Perfusion mapping and T₂* weighted MRI yielded reasonable time courses and were less sensitive to motion, compared to single slice acquisitions. Spectroscopic time courses of phosphocreatine, inorganic phosphate and pH with fitted PCr recovery time constants were consistent with literature in both GM and SOL. A significant ³¹P SNR increase was found when the VOI perceived adiabatic ¹H inversion which can be explained by NOE.

Sebastian Niesporek, Armin Nagel, Reiner Umathum, Nicolas Behl, Mark Ladd, Heinz-Peter Schlemmer, Daniel Paech

The cerebral metabolic rate of oxygen (CMRO₂) is an interesting biomarker and can be used as a diagnostic parameter in various neurodegenerative diseases or tumors. A dynamic ¹⁷O MRI inhalation method was optimized for application in a clinical setting and employed in two patient examinations to investigate CMRO₂ in human brain tumors as part of an ongoing pilot study. In tumor tissue, a decrease in oxygen consumption was detected, which is in consistent with the Warburg effect. To our knowledge, the presented work includes the first patient study with dynamic ¹⁷O MRI.

Jacques Stout, Arthur Coste, Franz Hozer, Franck Mauconduit, Sandro Romanzetti, Edouard Duchesnay, Cécile Lerman, Josselin Houenou, Frank Bellivier, Fawzi Boumezbeur

As an effective but poorly understood treatment for the prevalent bipolar disorder, studies focused on investigating the cerebral distribution of lithium are of important clinical interest. Here, we report our preliminary results obtained from 5 euthymic bipolar patients using ⁷Li MRI at 7T. Using a 3D SSFP sequence with ultra-short TE and Twisted Projection Imaging k-space sampling, we can confirm the heterogeneity of lithium brain distribution, as demonstrated by the individual and average concentration values in seven large regions-of-interest. 

Nicolas Behl, Armin Nagel, Reiner Umathum, Florian Maier, Mark Ladd, Mark Wielpütz, Hans-Ulrich Kauczor, Tanja Platt

²³Na lung MRI is a potential tool e.g. for investigating tumor viability and treatment response. The acquired data is, however, influenced by respiratory motion since breath-hold acquisitions are not possible due to the long measurement times. Here, we present a method for full flexibility in retrospective gating of 3D-radial data, combined with a Compressed-Sensing reconstruction. Up to 14 frames could be reconstructed from one in-vivo dataset, corresponding to a temporal resolution of 0.27 s. The temporal resolution of ²³Na lung MRI could potentially lead to a more accurate quantification of the Tissue Sodium Concentration in the human torso.