Diego Hernando¹, Ruiyang Zhao¹, Qing Yuan², Mounes Aliyari Ghasabeh³, Stefan Ruschke⁴, Xinran Miao¹, Dimitrios C. Karampinos⁴, Lu Mao¹, David T. Harris¹, Ryan J. Mattison¹, Michael R. Jeng⁵, Ivan Pedrosa², Ihab R. Kamel³, Shreyas Vasanawala⁵, Takeshi Yokoo², and Scott B. Reeder^1
1University of Wisconsin-Madison, Madison, WI, United States, ²University of Texas Southwestern Medical Center, Dallas, TX, United States, ³The Johns Hopkins University, Baltimore, MD, United States, ⁴Technical University of Munich, Munich, Germany, ⁵Stanford University, Palo Alto, CA, United States

We report the final results of an NIH funded study of MRI-based  quantification of liver iron. R2* MRI enables quantification of liver iron concentration (LIC), but the cross-vendor differences of R2*-based LIC estimation remain unknown. Therefore, we evaluated the performance of R2*-based LIC via a single-breath-hold, confounder-corrected R2*-MRI at both 1.5T and 3T, through a multi-center, multi-vendor study. We confirmed a linear relationship between R2* and LIC, with highly similar calibrations across centers and vendors. Calibrations for 1.5T and 3T were generated. The data generated in this study provide the necessary multi-center calibrations for broad dissemination of R2*-based LIC quantification.

Omar Isam Darwish^1,2,3, Radhouene Neji^1,3, Sami Jeljeli¹, Nader S Metwalli⁴, Jenna Feeley⁴, Yaron Rotman⁴, Rebecca J Brown⁴, Marc Ghany⁴, David E Kleiner⁵, Daniel Staeb⁶, Peter Speier⁷, Ralph Sinkus^1,2, and Ahmed M Gharib^4
1King's College London, London, United Kingdom, ²INSERM U1148, LVTS, University Paris Diderot, Paris, France, ³MR Research Collaborations, Siemens Healthcare Limited, Frimley, United Kingdom, ⁴National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, United States, ⁵National Cancer Institute, Bethesda, MD, United States, ⁶MR Research Collaborations, Siemens Healthcare Limited, Melbourne, Australia, ⁷MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany

Successful deployment of 3D liver MRE in the clinical assessment of fibrosis and inflammation requires a single breath-hold sequence to avoid geometric misalignment between different breath-holds and a phase-stable and efficient vibration for adequate wave penetration. We show initial data of Intenso MRE estimating the shear wave speed (Cs [m/s]) and the loss modulus (G’’ [kPa]). Both Cs and G’’ reflect a dependency on Ishak fibrosis and inflammation scores, respectively, in patients with chronic liver disease. In addition, we compare the magnitude of the shear modulus (|G*|) measured with Intenso and to the commonly utilized SE-EPI in such patients.

Nan Wang¹, Fardad M. Serry², Michael Ocasio², Yibin Xie², Yuheng Huang², Xinqi Li², Pei Han², Tianle Cao², Sen Ma², Fei Han³, Matthew Minton², Yubin Cai², Yujie Shan², Xiaoming Bi³, Anthony G. Christodoulou², Hsin-Jung Yang², Debiao Li², and Hui Han^2
1Stanford University, Stanford, CA, United States, ²Cedars-Sinai Medical Center, Los Angeles, CA, United States, ³Siemens Medical Solutions, Los Angeles, CA, United States

Liver MRI shows promise for rich morphologic and physiologic information. B0 inhomogeneity causes off-resonance spread at the liver-lung interfaces, degrading image quality and quantification accuracy for DWI, T1, and T2*/R2*. A novel high-order shim coil (UNIC) was built, minimizing the decoupling between the two overlapped shim and RF arrays, allowing the free design of shim loop topology in proximity of the target organ. Improved shimming from UNIC is demonstrated with increased FOV in liver imaging, showing significantly reduced distortion in liver DWI, increased image quality score of MOLLI T1 map, and reduced B0-offset-induced ADC, R2*, and B0 standard deviations.

Shuo ZHANG^1,2, Teresa Nolte², Masami Yoneyama³, Sven Nebelung², Christiane Kuhl², Alexandra Barabasch², and Jochen Herrmann^4
1Philips GmbH Market DACH, Hamburg, Germany, ²Diagnostic and Interventional Radiology, University Hospital RWTH Aachen, Aachen, Germany, ³Philips Japan, Tokyo, Japan, ⁴Department of Diagnostic and Interventional Radiology and Nuclear Medicine, Section of Pediatric Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

Multi-echo gradient-echo Dixon based on the chemical shift method is currently the standard for non-invasive in vivo quantification of the liver fat but requires breath-holding. In young children or sick patients this is often challenging or not feasible. Despite recent attempts using different free-breathing approaches to mitigate patient motions, these are not widely available or routinely used. In this work we employ the multi-echo Dixon sequence with 3D pseudo-golden angle radial stack-of-stars readout for free-breathing liver fat assessment and report our initial results in children and adults at 3T and 1.5T with phantom validation and comparison to the standard method.

Nathan Tibbitts Roberts^1,2, Daiki Tamada, PhD¹, Yavuz Muslu^1,3, Diego Hernando, PhD^1,3,4,5, and Scott B Reeder, MD, PhD^1,3,4,6,7
1Radiology, University of Wisconsin - Madison, Madison, WI, United States, ²Electrical Engineering, University of Wisconsin - Madison, Madison, WI, United States, ³Medical Physics, University of Wisconsin - Madison, Madison, WI, United States, ⁴Biomedical Engineering, University of Wisconsin - Madison, Madison, WI, United States, ⁵Electrical and Computer Engineering, University of Wisconsin - Madison, Madison, WI, United States, ⁶Medicine, University of Wisconsin - Madison, Madison, WI, United States, ⁷Emergency Medicine, University of Wisconsin - Madison, Madison, WI, United States

T1 is emerging as a quantitative MR biomarker of liver fibrosis, the most important histological change predictive of progressing chronic liver disease. 3D spoiled gradient echo (SGRE)-based T1 mapping is preferable in the abdomen for its short acquisition time, volumetric coverage, and robustness to motion. However, SGRE-based T1 mapping is confounded by tissue fat and B1 inhomogeneity. In this work we present a novel SGRE-based T1 mapping method that corrects for both fat and B1 inhomogeneity. Phantom experiments show excellent agreement with reference T1 values (slope=1.01, R²=1.00) and minimal bias (~5±23ms). Early results from 5 healthy volunteers are promising.

Ivica Just^1,2, Michael Leutner², Stefan Wampl³, Radka Klepochová², Siegfried Trattnig^1,4,5, Alexandra Kautzky-Willer², and Martin Krššák^2
1High-Field MR Centre, Department of Biomedical Imaging and Image-Guided Therapy, Medical University of Vienna, Vienna, Austria, ²Department of Internal Medicine III, Medical University of Vienna, Vienna, Austria, ³High-Field MR Center, Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria, ⁴CD laboratory for Clinical Molecular MR imaging (MOLIMA), Vienna, Austria, ⁵Institute for Clinical Molecular MRI in the Musculoskeletal System, Karl Landsteiner Society, St. Pölten, Austria

Detection of metabolites from human gallbladder poses some challenges due to its size and position. We compared breath-hold and respiratory triggered acquisition by ¹H SVS STEAM sequence on patients in supine position at 3T.  14 peaks of bile components were detected using both acquisition setups. Quantification of metabolite concentrations, corrected with measured T_2app relaxation times, showed results within the range of previously published data. STEAM sequence proved to be feasible for measurement of bile components at 3T in vivo, providing sufficient spectral quality for metabolite quantification in supine position with comparable results in both breath-hold and PACE navigated acquisition.

Johannes K. J. Raspe^1,2, Anh T. Van¹, Felix Harder¹, Sean McTavish¹, Johannes Peeters³, Kilian Weiss⁴, Marcus R. Makowski¹, Rickmer F. Braren¹, and Dimitrios C. Karampinos^1
1Department of Diagnostic and Interventional Radiology, School of Medicine, Technical University of Munich, Munich, Germany, ²Department of Physics, Technical University of Munich, Garching, Germany, ³Philips Healthcare, Eindhoven, Netherlands, ⁴Philips GmbH Market DACH, Hamburg, Germany

Physiological motion induces signal loss in diffusion-weighted imaging of the liver even when respiratory triggering is employed. Cardiac motion mostly affects the left liver lobe resulting in an inhomogeneous signal appearance and overestimation of the apparent diffusion coefficient (ADC). Spatial scaling is an algorithm that handles the intrinsic weighting of signal by rejecting bad acquisitions and voxels with subsequent calculation of a spatially dependent scaling factor for the final averaging. The present work shows that by adding such a spatial scaling postprocessing step, liver signal homogeneity can be increased, and overestimation of the ADC can be reduced.

Joey Roosen¹, Lovisa E. L. Westlund Gotby¹, Mark J. Arntz¹, Jurgen J. Fütterer¹, Marcel J. R. Janssen¹, Meike W. M. van Wijk¹, Christiaan G. Overduin¹, and J. Frank W. Nijsen^1
1Department of Medical Imaging, Radboud University Medical Center, Nijmegen, Netherlands

Transarterial radioembolization (TARE) is a treatment for liver tumors based on injection of radioactive microspheres in the hepatic arteries under angiography guidance. Conventionally, there is no feedback on the dose distribution during treatment and dosimetry can only be evaluated after treatment. As holmium-166 microspheres used for TARE can be quantified with MRI, we investigated the feasibility and safety of performing TARE in a 3-T MRI in six patients. Multi-echo gradient echo imaging was performed at set time points during administration and provided intraprocedural insight into the microsphere distribution. Our findings may prove useful for providing a personalized approach to TARE.