ISMRM 24th Annual Meeting & Exhibition • 07-13 May 2016 • Singapore

Scientific Session: Renal/Adrenal/Male Pelvis

Wednesday, May 11, 2016
Summit 2
13:30 - 15:30
Moderators: Sooah Kim, Riccardo Lattanzi

Frequency tensor imaging (FTI) at a single orientation by vector projection
Luke Xie1, Russell Dibb2, Chunlei Liu2, and Vivian S. Lee1
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.

Automatic Renal Cortex Segmentation Using Machine Learning for MR Urography
Umit Yoruk1,2, Brian Hargreaves2, and Shreyas Vasanawala2
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.

Magnetic Resonance Elastography (MRE) for the assessment of renal allograft function
Jing Guo1, Stephan Marticorena1, Florian Dittmann1, Andreas Fehlner1, Sebastian Hirsch1, Thomas Fischer1, Jürgen Braun2, and Ingolf Sack1
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.

3D Printed Renal Cancer Models Derived from MRI data: Application in Pre-surgical Planning
Nicole Wake1, Temitope Rude2, William C Huang2, Michael D Stifelman2, James F Borin2, Daniel K Sodickson1, and Hersh Chandarana1
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.

Diurnal Variation of Renal Blood Flow using 4D Flow MRI
Sylvana García-Rodríguez1, Alejandro Roldán-Alzate1,2, Camilo A. Campo1, Scott B. Reeder1, Oliver Wieben1,3, and Christopher J. François1
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.

Reduced susceptibility anisotropy in ischemia reperfusion kidneys: evidence of cellular organization as a source of contrast
Luke Xie1, Vivian Lee1, Russell Dibb2, Yi Qi2, Nian Wang3, G. Allan Johnson2, and Chunlei Liu3
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.

Prospective Image Alignment for Time-Resolved Renal BOLD MRI
Inge Manuela Kalis1, David Pilutti1, Axel Joachim Krafft1,2,3, and Michael Bock1
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.

MR Elastography of The Prostate with A Mode-Conversion Endourethral Driver: Feasibility at 3.0 T
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. Ehman2
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.

Adrenal gland iron measurement using MRI-R2* in patients with iron overload: a feasibility Study
Sarah Keller1, Bjoern Schoennagel1, Zhiyue Jerry Wang2, Hendrick Kooijman3, Gerhard Adam1, Roland Fischer4,5, and Jin Yamamura1
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. 

Improving the accuracy of renal perfusion measurements from ASL by using multiple TIs: Validation with DCE MRI
Christopher Charles Conlin1,2, Yangyang Zhao2, and Jeff Lei Zhang1,3
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.

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