Luke Xie¹, Russell Dibb², Chunlei Liu², and Vivian S. Lee^1
1Utah Center for Advanced Imaging Research, Radiology, University of Utah, Salt Lake City, UT, United States, ²Brain Imaging Analysis Center, Radiology, Duke University Medical Center, Durham, NC, United States

STI is sensitive to tissue microstructure and can detect subtle changes in disease states. However, STI remains a challenging protocol due to the physical reorientation with respect to the magnetic field. Current studies of the heart and kidney are limited to ex-vivo imaging. In this study, we present frequency tensor imaging (FTI) at a single image acquisition without rotating the object. FTI takes advantage of tissue structure already pointing in multiple directions with respect to the magnetic field in a single orientation dataset. This technique offers the potential for susceptibility-based tensor imaging of the abdomen in the clinic.

Umit Yoruk^1,2, Brian Hargreaves², and Shreyas Vasanawala^2
1Electrical Engineering, Stanford University, Stanford, CA, United States, ²Radiology, Stanford University, Stanford, CA, United States

Glomerular filtration rate (GFR) estimation can be achieved using dynamic contrast enhanced MRI (DCE-MRI) and pharmacokinetic models. The segmentation of kidneys is essential for obtaining the time intensity curves needed by these models. Manual segmentation of kidneys is one of the most time consuming and labor-intensive steps of GFR analysis as it can take several hours and require trained personnel. Here, we introduce a novel method for automatic renal segmentation based on morphological segmentation and machine learning, and assess the performance of the method.

Jing Guo¹, Stephan Marticorena¹, Florian Dittmann¹, Andreas Fehlner¹, Sebastian Hirsch¹, Thomas Fischer¹, Jürgen Braun², and Ingolf Sack^1
1Radiology, Charité - Universitätsmedizin Berlin, Berlin, Germany, ²Department of Medical Informatics, Charité - Universitätsmedizin Berlin, Berlin, Germany

In vivo assessment of the renal allograft function post kidney transplantation is challenging. We here demonstrate that multifrequency MR elastography (MMRE) can detect renal allograft dysfunction with good diagnostic accuracy (AUROC:0.91 [95% CI 0.80-1.02; p < 0.001]). Renal stiffness is significantly lower in dysfunctional transplant kidney and correlates moderately with glomerular filtration rate and resistive index. MMRE may serve as a non-invasive imaging maker to detect renal allograft dysfunction in an early stage and to monitor renal allograft function longitudinally.

Nicole Wake¹, Temitope Rude², William C Huang², Michael D Stifelman², James F Borin², Daniel K Sodickson¹, and Hersh Chandarana^1
1Bernard and Irene Schwartz Center for Biomedical Imaging, Center for Advanced Imaging Innovation and Research, Department of Radiology, New York University School of Medicine, New York, NY, United States, ²Department of Urology, New York University School of Medicine, New York, NY, United States

The objective of this study was to determine how patient-specific 3D printed renal tumor models derived from MRI data can influence pre-surgical planning.  These 3D printed models may alter the surgical plan, especially for trainees and young surgeons.  Future, outcome based studies may help to determine the impact of these 3D printed models on surgical outcomes and patient care.

Sylvana García-Rodríguez¹, Alejandro Roldán-Alzate^1,2, Camilo A. Campo¹, Scott B. Reeder¹, Oliver Wieben^1,3, and Christopher J. François^1
1Radiology, University of Wisconsin-Madison, Madison, WI, United States, ²Mechanical Engineering, University of Wisconsin-Madison, Madison, WI, United States, ³Medical Physics, Univerisity of Wisconsin-Madison, Madison, WI, United States

This study investigated the diurnal changes in renal blood flow in healthy volunteers using 4D flow MRI, to determine the optimal time of day to perform renal blood flow measurements. Five 4D flow MRI acquisitions were performed throughout the day in seven healthy subjects to mimic potential imaging scheduling time points. Significant differences in renal blood flow were observed depending upon time of day and prandial status. This study confirms the importance of timing of renal MRI studies assessing kidney function.

Luke Xie¹, Vivian Lee¹, Russell Dibb², Yi Qi², Nian Wang³, G. Allan Johnson², and Chunlei Liu^3
1Radiology, University of Utah, Salt Lake City, UT, United States, ²Center for In Vivo Microscopy, Radiology, Duke University Medical Center, Durham, NC, United States, ³Brain Imaging Analysis Center, Radiology, Duke University Medical Center, Durham, NC, United States

Diffusion tensor imaging (DTI) and susceptibility tensor imaging (STI) can assess the integrity of the nephron where STI provides additional molecular information. STI has demonstrated sensitivity to changes in kidney disease models. The source of susceptibility anisotropy is hypothesized to be the organized tubules, basement membrane, and the organized lipids. Ischemia reperfusion is one particular disease model with well known cellular disorganization in specific nephron segments. In the present study, we applied STI in a model of ischemia perfusion to demonstrate changes in susceptibility anisotropy and to provide additional evidence that the cellular organization is a major contributor.

Inge Manuela Kalis¹, David Pilutti¹, Axel Joachim Krafft^1,2,3, and Michael Bock^1
1Dept. of Radiology - Medical Physics, University Medical Center Freiburg, Freiburg, Germany, ²German Cancer Consortium (DKTK), Heidelberg, Germany, ³German Cancer Research Center (DKFZ), Heidelberg, Germany

Renal function can be analyzed by time-resolved BOLD MRI before, during and after a functional challenge. Inconsistent kidney positions from one measurement to another hamper the analysis of renal parenchyma and medulla over time. Here, a new method, Kidney ALIgnment for BOLD Renal Imaging (KALIBRI), with prospective rigid image registration of each kidney is proposed.

Jin Wang¹, Kevin J. Glaser², Bingjun He¹, Tianhui Zhang¹, Jun Pang³, Ziying Yin², Zhuang Kang¹, Qungang Shan¹, Meng Yin², Forghanian-Arani Arvin², and Richard L. Ehman^2
1Department of Radiology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China, People's Republic of, ²Department of Radiology, Mayo Clinic, Rochester, MN, United States, ³Department of Urology, The Third Affiliated Hospital of Sun Yat-Sen University, Guangzhou, China, People's Republic of

Prostate cancer(PCa) is one of the leading causes of cancer-related deaths in men. Detection of clinically significant PCa is a major challenge. We evaluated the feasibility of a novel approach for quantitatively imaging the stiffness of prostate gland, using a conventional urinary catheter as a source of shear waves for MR elastography. Results in 19 examinations showed that the approach, which uses conventional commercially-available MRE drivers can generate shear wave fields in the prostate that are suitable processing. Measurements of regional prostate stiffness in patients with benign prostatic hypertrophy and PCa reveal trends that provide motivation for further evaluation of prostatic MRE.

Sarah Keller¹, Bjoern Schoennagel¹, Zhiyue Jerry Wang², Hendrick Kooijman³, Gerhard Adam¹, Roland Fischer^4,5, and Jin Yamamura^1
1Diagnostic and Interventional Radiology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany, ²Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States, ³Philips Medical Care, Hamburg, Germany, ⁴Radiology, Children’s Hospital & Research Center Oakland, Oakland, CA, United States, ⁵Biochemistry, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

In recent years, hepatic, cardiac, and even pancreatic iron deposition has been studied in detail. However, the presence and incidence of iron disposition of normal-sized adrenal glands has not been adequately reported. The purpose of this study was to evaluate the levels of iron deposition in the adrenal glands in patients with iron overload. 

Christopher Charles Conlin^1,2, Yangyang Zhao², and Jeff Lei Zhang^1,3
1Utah Center for Advanced Imaging Research, University of Utah, Salt Lake City, UT, United States, ²Bioengineering, University of Utah, Salt Lake City, UT, United States, ³Radiology, University of Utah School of Medicine, Salt Lake City, UT, United States

This study presents an approach for measuring renal perfusion from multi-TI ASL data and examines the impact of TI-sampling density on perfusion estimation. Our approach incorporates a tracer-kinetic model of the ASL difference signal and a correction for inversion-efficiency artifacts. It was used to measure renal perfusion in human subjects from ASL data sampled at different numbers of TIs and validated against an established DCE-MRI technique. For ASL data sampled at more than two TIs, our approach showed good agreement and correlation with DCE-MRI, demonstrating robust modeling of the ASL difference signal and accurate measurement of renal perfusion.