Nathalie Barrau¹, Claire Pellot Barakat¹, Zhongzheng He¹, Tolga Emre¹, Angéline Nemeth¹, Anass Afkir¹, Wenpei Cai¹, Vincent Brulon¹, Tanguy Boucneau², Brice Fernandez², Florent Besson¹, Vincent Lebon¹, and Xavier Maître^1
1Université Paris-Saclay, CEA, CNRS, Inserm, BioMaps, Orsay, France, ²General Electric Healthcare, Buc, France

Spirometry is a standard exam in pulmonary function testing for assessing the efficiency of global ventilation from flow-volume loops measured at the mouth during forced respiratory cycles. A newly developed technique, 3D MR spirometry, makes use of dynamic magnetic resonance imaging during spontaneous breathing to produce regional characterization of the lung function. The sensitivity of the technique was challenged with respect to gravity by extracting the associated ventilation gradients in prone and supine healthy volunteers.

Simone Hufnagel¹, Matthias Anders², Christoph Stefan Aigner¹, Helge Herthum², Heiko Tzschaetzsch², Tobias Schaeffter^1,3,4, Ingolf Sack², and Christoph Kolbitsch^1
1Physikalisch-Technische Bundesanstalt (PTB), Braunschweig and Berlin, Germany, ²Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany, ³School of Imaging Sciences and Biomedical Engineering, King's College London, London, United Kingdom, ⁴Department of Biomedical Engineering, Technical University of Berlin, Berlin, Germany

MR elastography (MRE) provides valuable quantitative information about the mechanical properties of brain tissues. However, due to SNR limitations, often only low through-plane resolution is possible. We present super-resolution MRE based on multiple stacks of complex 3D wavefields of the brain resulting in elastograms with isotropic (1×1×1) mm³ resolution. The approach was evaluated for the in-vivo brain and showed improved visibility of fine structures while presenting consistent shear wave speed values.

Luca Zilberti¹, Alessandro Arduino¹, Umberto Zanovello¹, and Oriano Bottauscio^1
1INRIM, Torino, Italy

A local-integral solution of the Electric Properties Tomography (EPT) problem is proposed. The method exploits a trick to consider the Helmholtz equation that regulates EPT as a Poisson equation. Then, it inverts the equation under the local homogeneity assumption, using Green's theorem. The approach turns out to be equivalent to the traditional Helmholtz-EPT.

Dushyant Kumar¹, Ritobrato Datta², Micky K Bacchus², Narayan Datt Soni¹, Ravi Prakash Reddy Nanga¹, Brenda Banwell ², and Ravinder Reddy^1
1Radiology, Center for Advanced Metabolic Imaging in Precision Medicine (CAMIPM), University of Pennsylvania, Philadelphia, PA, United States, ²Neurology, Children's Hospital of Philadelphia, Philadelphia, PA, United States

Several proton magnetic resonance spectroscopy (¹H-MRS) based studies have reported regional alterations of glutamate metabolism in both acute and chronic multiple sclerosis (MS) pathologies, including in normal appearing white matter and mixed tissues. Despite its well-established capability for detecting altered glutamate metabolism, ¹H-MRS is hampered by the low spatial resolution that precludes the measurements from small MS lesions. We demonstrate the feasibility of performing glutamate weighted imaging using chemical exchange saturation transfer with B₀- and B₁- corrections in pediatric-onset MS subjects.  The proposed model for B₁-calibration is a major improvement over the phenomenological method previously proposed by our group.

Naveen Murthy¹, Jon-Fredrik Nielsen², Steven T. Whitaker¹, Melissa W. Haskell^1,2, Scott D. Swanson³, Nicole Seiberlich³, and Jeffrey A. Fessler^1
1Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, MI, United States, ²fMRI Lab, University of Michigan, Ann Arbor, MI, United States, ³Radiology, University of Michigan, Ann Arbor, MI, United States

Mapping myelin water exchange rates could potentially be useful in helping us understand and characterize different diseases in the brain. It is a challenging quantitative parameter mapping problem to estimate multi-compartment exchange. This work focuses on scan design, with an aim of estimating exchange maps with good precision. In particular, a set of balanced steady-state free precession (bSSFP) sequences are optimized to estimate exchange rates in white matter (WM), for a two-pool model. Quantitative exchange maps are shown for a simulated phantom, using this optimized scan design.

Octavia Bane^1,2, Christopher Kyriakakos¹, Nicolas Gillingham¹, Jordan Cuevas^1,2, Kirolos Meilika³, Jorge Daza³, Amir Horowitz⁴, Bachir Taouli^1,2, Ketan Badani³, and Sara Lewis^1,2
1Department of Radiology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, ²BioMedical Engineering and Imaging Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States, ³Department of Urology, Icahn School of Medicine at Mount Sinai, New York, NY, United States, ⁴Division of Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States

In this prospective, single-center study, we evaluated the use of qualitative features and quantitative radiomics features from MRI for diagnosis and characterization of clear cell renal cell carcinoma (ccRCC). Qualitative features in isolation were of no value for diagnosing ccRCC, while the ccRCC likelihood score, which takes into account qualitative T2w signal and contrast enhancement pattern, had comparable diagnostic performance to the quantitative radiomics features. Quantitative radiomics features had good to excellent diagnostic performance in identifying ccRCC, as well as correlated to grade of ccRCC.

Harmen Reyngoudt^1,2, Pierre-Yves Baudin^1,2, Ericky Caldas de Almeida Araujo^1,2, Brenda L Wong^3,4, Pierre G Carlier⁵, and Benjamin Marty^1,2
1NMR Laboratory, Neuromuscular Investigation Center, Institute of Myology, Paris, France, ²NMR Laboratory, CEA/DRF/IBFJ/MIRCen, Paris, France, ³Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States, ⁴UMass Memorial Medical Center, Worcester, MA, United States, ⁵University Paris-Saclay, CEA, EA, DRF, Service Hospitalier Frédéric Joliot, Orsay, France

In most clinical quantitative MRI studies, using fat-water imaging, a mean fat fraction value per region of interest is generally used. The aim of this study was to look into the longitudinal changes in FF distribution on an individual patient basis, in dystrophic muscle, and at the same time, investigate whether differences were observed between treated and non-treated patients. As shown here, even if the mean fat fraction is the same between two patients or across time, there might be significant differences in the respective FF distributions, and might reveal, in retrospect, differential clinical or functional changes.

Vasily L. Yarnykh¹, Alena A. Kisel¹, Andrey E. Akulov², and Alexander Drobyshevsky^3
1Radiology, University of Washington, Seattle, WA, United States, ²Institute of Cytology and Genetics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russian Federation, ³NorthShore University HealthSystem, Evanston, IL, United States

The data-driven surrogate B₁ field correction algorithm was recently developed to eliminate B₁-related spatial errors in the macromolecular proton fraction (MPF) and R₁ maps obtained using the fast single-point method. The algorithm obviates the need for acquisition of actual B₁ field maps, thus extending the routine use of fast MPF mapping. Initially, the surrogate B₁ correction was applied to the human brain imaging at 3T. In this study, the method has been adopted and validated for small-animal imaging utilizing dedicated ultra-high-field MRI scanners. Particularly, we report guidelines on using surrogate B₁ field correction in 9.4T and 11.7T magnetic fields.

Fakhereh Movahedian Attar¹, Evgeniya Kirilina ^1,2, Christian Schneider^1,3, Daniel Haenelt¹, Luke J. Edwards¹, Kerrin J. Pine¹, Carsten Jäger^1,4, Katja Reimann¹, Andreas Pohlmann⁵, Joao Periquito^5,6, Tobias Streubel⁷, Siawoosh Mohammadi^1,7, Thoralf Niendorf^5,8, Markus Morawski⁴, and Nikolaus Weiskopf^1,9
1Department of Neurophysics, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany, ²Department of Education and Psychology, Center for Cognitive Neuroscience Berlin, Free University Berlin, Berlin, Germany, ³Faculty of Physics and Earth Sciences, Leipzig University, Leipzig, Germany, ⁴Paul Flechsig Institute of Brain Research, University of Leipzig, Leipzig, Germany, ⁵Berlin Ultrahigh Field Facility, Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, ⁶Institute of Physiology, Charité- Universitätsmedizin Berlin, Berlin, Germany, ⁷Department of Systems Neuroscience, University Medical Center Hamburg-​Eppendorf, Hamburg, Germany, ⁸Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the Max Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, ⁹Felix Bloch Institute for Solid State Physics, Faculty of Physics and Earth Sciences, Leipzig University, Leipzig, Germany

U-fibres are the most abundant white matter fibres and yet are highly underrepresented in the MRI-derived human brain connectome. Development of validated in vivo pipelines for comprehensive mapping of these short association fibres is therefore essential. Here, we show the correspondence of the geometries of U-fibres connecting early visual cortices mapped in vivo using sub-millimetre resolution diffusion weighted imaging (DWI) tractography to those obtained in a post-mortem brain tissue sample using ultra-high resolution DWI tractography.