Edward M Lawrence^1,2 and David H Kim^1
1Radiology, UW-Madison School of Medicine and Public Health, Madison, WI, United States, ²Radiology, WS Middleton VA Hospital, Madison, WI, United States

Retrospective evaluation of intra-rectal gel suppression on DWI from 60 rectal MRIs.  The DWI, including b1000, computed synthetic b1500, and ADC maps were evaluated by 2 radiologists independently using a 5 point Likert scale with scores of 4-5 considered fully diagnostic. The median suppression score was significantly greater than 3 for both readers (p<0.05) with fully diagnostic suppression achieved in 57/60 (95.0%) and 53/60 (88.3%) cases for reader 1 and 2, respectively. No study was given a score of 1 or 2 by either reader. These results suggest that gel does not impede reader evaluation for tumor restriction at DWI. 

Brandon Zanette¹, Samal Munidasa^1,2, Yonni Friedlander^1,2, Felix Ratjen^1,3, and Giles Santyr^1,2
1Translational Medicine, The Hospital for Sick Children, Toronto, ON, Canada, ²Medical Biophysics, University of Toronto, Toronto, ON, Canada, ³Division of Respiratory Medicine, The Hospital for Sick Children, Toronto, ON, Canada

A rapid 3D stack-of-spirals (3D-SoS) sequence was used for hyperpolarized ¹²⁹Xe ventilation imaging in pediatric cystic fibrosis and healthy controls, allowing for 5x reduction in scan duration and breath-hold compared to a commonly used 2D gradient echo (2D-GRE) sequence. The ventilation defect percent (VDP) measured with 3D-SoS was not significantly different from VDP measured with 2D-GRE. Additionally, the transient drop in SpO₂ associated with xenon breath-holds was reduced with the shorter breath-hold afforded by 3D-SoS. In future, the reduced acquisitions durations offered by 3D-SoS may allow for improved tolerability, or may be traded for improved resolutions.

Zijian Zhou¹, Bikash Panthi¹, David E. Rauch¹, Jong Bum Son¹, Carol C. Wu¹, Steven H. Lin¹, Mark D. Pagel¹, and Jingfei Ma^1
1The University of Texas MD Anderson Cancer Center, Houston, TX, United States

We applied a deep learning (DL) model developed for ¹⁸F-FDG PET/CT of mantle cell lymphoma to esophageal cancers on ¹⁸F-FDG PET/CT and diffusion-weighted MRI. We compared the performance of the DL-based segmentation with the manual segmentation on PET and evaluated the quantitation on both PET and apparent diffusion coefficient (ADC). The model achieved promising results of detecting and segmenting esophageal cancers, and the DL-based imaging metrics were consistent with the reference standards.

Sarah Palmquist¹, Usama Salem¹, Nir Stanietzky¹, Jia Sun², Xinzeng Wang³, Ersin Bayram³, Ken-Pin Hwang⁴, Jong Bum Son⁴, Peng Wei², Randy Ernst¹, Harmeet Kaur¹, and Jingfei Ma^4
1Abdominal Imaging, M.D. Anderson Cancer Center, Houston, TX, United States, ²Biostatistics, M.D. Anderson Cancer Center, Houston, TX, United States, ³GE Healthcare, Houston, TX, United States, ⁴Imaging Physics, M.D. Anderson Cancer Center, Houston, TX, United States

Multiplanar high resolution T2-weighted (T2W) imaging with a 2D fast spin echo (FSE) sequence is currently an essential component of rectal cancer MRI. In this work, we performed T2W imaging of rectal cancer with a 3D FSE sequence and evaluated the quality and potential clinical value of the images after applying a postprocessing deep learning reconstruction (DLR) algorithm. We found that DLR images are non-inferior to conventional images and there are fair-moderate inter-reader agreements in a large majority of the categories evaluated for image quality and clinical usefulness.
 

Aline Xavier^1,2,3, Constanza Gainza^4,5, Flavia Zacconi^6,7,8, Daniel Cabrera^9,10, Marco Arese^9,11, Carlos Sing-Long^2,3,4,5,8, and Marcelo Andia^2,3,12
1Instituto de Ciencias de la Ingeniería, Universidad de O’Higgins, Rancagua, Chile, ²Millennium Nucleus for Cardiovascular Magnetic Resonance, Santiago, Chile, ³Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁴Millennium Nucleus Center for the Discovery of Structures in Complex Data, Santiago, Chile, ⁵Institute for Mathematical and Computational Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁶Faculty of Chemistry and Pharmacy, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁷Research Center for Nanotechnology and Advanced Materials CIEN-UC, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁸Institute for Biological and Medical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁹Gastroenterology Department, Pontificia Universidad Católica de Chile, Santiago, Chile, ¹⁰Faculty of Medical Sciences, Universidad Bernardo O’Higgins, Santiago, Chile, ¹¹Center of Aging and Regeneration (CARE), Pontificia Universidad Católica de Chile, Santiago, Chile, ¹²Radiology Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile

In this study, we analyzed the liver fatty acids results obtained by magnetic resonance spectroscopy and gas chromatography in non-alcoholic fatty liver disease (NAFLD) mice with principal component analysis (PCA) and a clustering method. The study was made with two different mouse models (CDAA and Western diet), and a control group. Our results, as evidenced by PCA, showed that the liver fatty acid composition changed as NAFLD progressed and it was possible to identify the 3 most relevant NAFLD groups with MRS (healthy, steatosis, and steatohepatitis) with excellent agreement with the gold-standard histopathological scores.

Pedro Izquierdo Lehmann^1,2, Aline Xavier^2,3,4, Marcelo Andia^2,4,5, and Carlos A Sing-Long^1,2,4,6,7
1Institute for Mathematical and Computational Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, ²Millennium Nucleus for Cardiovascular Magnetic Resonance, Santiago, Chile, ³Instituto de Ciencias de la Ingeniería, Universidad de O’Higgins, Rancagua, Chile, ⁴Biomedical Imaging Center, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁵Radiology Department, School of Medicine, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁶Institute for Biological and Medical Engineering, Pontificia Universidad Católica de Chile, Santiago, Chile, ⁷Millennium Nucleus Center for the Discovery of Structure in Complex Data, Santiago, Chile

Nonalcoholic fatty liver disease (NAFLD) is a common liver disorder that is the first step in a cascade of liver damage. Hence, there is a clinical need for non-invasive, early identification of patients. We hypothesize that the intra-hepatocyte fatty acid composition provides information about NAFLD. To test this, the ¹H-MRS spectra of fatty acids in the livers of healthy and NAFLD mice were measured at 9.4 T. Exploratory data analysis shows the spectra can be correctly classified with SVMs. Our results open an opportunity to develop a non-invasive tool for staging NAFLD patients without the need of liver biopsy.

Arthur Peter Wunderlich^1,2, Holger Cario³, Stephan Kannengießer⁴, Lena Hering¹, Michael Götz^1,2, Meinrad Beer¹, and Stefan Andreas Schmidt^1
1Dept. for Diagnostic and Interventional Radiology, Ulm University, Medical Center, Ulm, Germany, ²Section for Experimental Radiology, Ulm University, Medical Center, Ulm, Germany, ³Clinic of Pediatrics and Adolescent Medicine, Ulm University, Medical Center, Ulm, Germany, ⁴MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany

Purpose: To analyze the Liver-Iron-Content-(LIC)-R₂*-calibration with respect to co-factors.

Methods: 116 patients were scanned with spin-echo (Ferriscan^® protocol) and gradient-echo sequences. R₂* was correlated to LIC reference values for all patients together and in subgroups divided by e.g. age, gender and underlying diseases. Linear correlations were analyzed with R₂* only and including MR-PDFF as suspected co-factor.

Results: Deviating slopes of regression lines were found e.g. in patients after splenectomy vs. patients with spleen, influence of MR-PDFF amongst others in females below 17 years.

Conclusion: Co-factors like disease patterns should be considered in gradient echo based LIC quantification.

Arthur Peter Wunderlich^1,2, Holger Cario³, Stephan Kannengießer⁴, Veronika Grunau¹, Michael Götz^1,2, Meinrad Beer¹, and Stefan Andreas Schmidt^1
1Dept. for Diagnostic and Interventional Radiology, Ulm University, Medical Center, Ulm, Germany, ²Section for Experimental Radiology, Ulm University, Medical Center, Ulm, Germany, ³Clinic of Pediatrics and Adolescent Medicine, Ulm University, Medical Center, Ulm, Germany, ⁴MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany

Purpose: To test liver segmentation of 3D-multi-gradient-echo MRI data and segmental R₂* evaluation.

Methods: 44 patients examined by multi-gradient-echo MRI underwent semiautomatic liver segmentation and subdivision into nine segments. Segmental R₂* values were analyzed in all patients together and in patient subgroups.

Results: R₂* was lowest in segment 1 (S1), differences to S1 were significant for S3, S5 and S6, highly significant to S2 and S7. Patients with high average R₂* showed also significant differences to S1 in some segments.

Conclusions: Inhomogeneity of hepatic iron distribution was found. Low R₂* in S1 may be explained by its special vascular supply.

Bingjie Yang¹, Patrick Metze¹, Anke Balasch¹, Kilian Stumpf¹, Meinrad Beer², Wolfgang Rottbauer¹, and Volker Rasche^1
1Department of Internal Medicine II, Ulm University Medical Center, Ulm, Germany, ²Department of Radiology, Ulm University Medical Center, Ulm, Germany

MRI lung imaging is challenging due to cardiac and respiratory motion and the short T2*. In this study the reproducibility of lung function parameters derived from data acquired either from a breath-hold or free-breathing tiny golden angle UTE (2D tyGA UTE) technique have been assessed. Inter-observer and inter-measurement reproducibility was assessed for different lung parameters including lung density and qualitative and quantitative ventilation and perfusion. In general, a very good inter-observer reproducibility and superior reproducibility of the lung function parameters was observed for the free-breathing approach.

Peter J Niedbalski¹, Chase Hall¹, and Mario Castro^1
1Internal Medicine, University of Kansas Medical Center, Kansas City, KS, United States

Hyperpolarized ¹²⁹Xe MRI (Xe-MRI) can be used to acquire images of pulmonary ventilation and gas exchange. These ventilation and gas exchange images are typically acquired in separate breath-holds, which lengthens scan time, increases cost, and requires more of patients. We have combined 3D spiral (FLORET) ventilation imaging with radial 1-point Dixon gas exchange imaging within a single-breath-hold scan. This single-breath-hold scan produces both a gas exchange and a “high-resolution” (4x4x4 mm³ voxels) ventilation image that are qualitatively and quantitatively similar to images acquired in dedicated breath-holds. This increase in efficiency improves the clinical feasibility of hyperpolarized ¹²⁹Xe MRI.