Renal Imaging: Development & Applications

Tuesday 13 May 2014

Scott A. Kruse¹, Kevin J. Glaser¹, Jun Chen¹, Dawn S. Milliner², Sudhakar K. Venkatesh¹, and Richard L. Ehman^1
1Department of Radiology, Mayo Clinic, Rochester, Minn., United States, ²Division of Nephrology and Hypertension, Mayo Clinic, Rochester, Minn., United States

There is a clinical need for more effective noninvasive tools for assessing the extent of renal parenchymal disease. MR Elastography has been shown to be effective in staging hepatic fibrosis. Here we developed a 3D wavefield protocol for applying MRE to the kidneys. Four normal volunteers and five patient volunteers with primary hyperoxaluria were enrolled. The mean renal parenchymal stiffness for the normal volunteers was 2.99 + 1.08 kPa at 60 Hz. In addition, the patient results provide preliminary evidence of a trend of decreased parenchymal stiffness with increasing urinary oxalate levels.

Jing Guo¹, Kaspar-Josche Streitberger¹, Heiko Tzschaetzsch¹, Sebastian Hirsch¹, Juergen Braun², and Ingolf Sack^1
1Department of Radiology, Charite - Universitaetsmedizin Berlin, Berlin, Berlin, Germany, ²Department of Medical Informatics, Charite - Universitaetsmedizin Berlin, Berlin, Germany

Renal fibrosis can be detected by MR elastography (MRE) based on altered mechanical tissue properties. However, MRE has been limited in providing high resolution mechanical parameter maps of the kidney due to low-resolution shear wave images and ill-posed solutions of the inverse problem of MRE. We here overcome both problems by an optimized single shot MRE sequence and multifrequency dual elasto visco inversion. As a result, high resolution MRE maps are obtained which for the first time enable radiologists to analyze the regional variation of the kidney's viscoelastic properties on a pixel-to-pixel base.

Aaryani Tipirneni-Sajja^1,2, Ralf B Loeffler¹, Niels Oesingmann³, Yutong Duan¹, Adam M Winchell^1,2, Ruitian Song¹, Beth McCarville¹, Melissa Hudson⁴, Sherri L Spunt⁴, and Claudia M Hillenbrand^1
1Radiological Sciences, St. Jude Children's Research Hospital, Memphis, TN, United States, ²Biomedical Engineering, University of Memphis, Memphis, TN, United States, ³Siemens Medical Solutions USA, Inc, New York, NY, United States, ⁴Oncology, St. Jude Children's Research Hospital, Memphis, TN, United States

Renal GFR is a very important quantitative index of renal function in health and disease. Several methods are available to estimate GFR using DCE-MRI, but a precise and unbiased method to estimate GFR remains to be developed. This study estimates GFR by DCE-MRI using a two-compartment (2C) model that disregards tubular outflow and automatically picks the end-of-uptake point (auto2C) and compares these results with those from the gold standard GFR measurement (99mTc-DTPA) in long-term survivors of unilateral Wilms’ tumor.

Yue Zhang¹, Ananth Madhuranthakam^1,2, Qing Yuan¹, Ivan Dimitrov^2,3, Yin Xi¹, Naira Muradyan⁴, Vitaly Margulis⁵, James Brugarolas^6,7, Payal Kapur⁸, and Ivan Pedrosa^1,2
1Radiology, UT Southwestern Medical Center, Dallas, Texas, United States, ²Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, Texas, United States, ³Philips Medical Systems, Cleveland, Ohio, United States, ⁴iCAD, Inc., Nashua, New Hampshire, United States, ⁵Urology, UT Southwestern Medical Center, Dallas, Texas, United States, ⁶Internal Medicine, UT Southwestern Medical Center, Dallas, Texas, United States,⁷Developmental Biology, UT Southwestern Medical Center, Dallas, Texas, United States, ⁸Pathology, UT Southwestern Medical Center, Dallas, Texas, United States

The purpose of this study was to investigate the correlation between in vivo assessments of vascular heterogeneity within renal masses measured by arterial spin labeling (ASL) MRI and dynamic contrast-enhanced (DCE) MRI techniques at 3T. Quantitative ASL and DCE parameters were obtained from the whole tumor, and from areas with high- and low- blood flow within the tumor. ASL measured blood flow in renal masses correlates with DCE-derived parameters of tumor vascularity. Both ASL and DCE MRI at 3T allow for detection of intra-tumoral vascular heterogeneity in renal masses, providing a tool for assessment and monitoring of angiogenesis in renal cancer.

Byron Gaing¹, Eric Edward Sigmund¹, William Huang², James Babb¹, David Stoffel¹, and Hersh Chandarana^1
1Radiology, NYU Langone Medical Center, New York, New York, United States, ²Urology, NYU Langone Medical Center, New York, United States

Renal cell carcinomas are a heterogeneous group of tumors not only with their varying biologic behavior but also in their response to targeted therapies. Previous work has shown that IVIM parameters are useful in differentiating common subtypes of RCC based on whole ROI analysis. Our results confirm previous work showing a clear trend separating more vascular (clear cell) from less vascular (papillary) tumor subtypes using the IVIM metric fp. Additionally, our initial results suggest differentiation between benign and malignant subtypes of renal tumors may also be possible. These findings could potentially impact surgical planning.

Harald Kramer^1,2, Alejandro Roldan-Alzate², Chrstopher J Francois², Scott B Reeder^2,3, and Oliver Wieben^2,3
1Department of Radiology, Ludwig-Maximilians-University Munich, Munich, Germany, ²Department of Radiology, University of Wisconsin - Madison, Madison, Wisconsin, United States, ³Department of Medical Physics, University of Wisconsin - Madison, Madison, Wisconsin, United States

Ingestion of a meal alters blood flow in the entire mesenteric vasculature. The same accounts for portal hypertension. The presented study evaluates changes in blood flow alterations pre and post meal in patients with portal hypertension and healthy volunteers. After a meal cardiac output and thus flow in the supraceliac aorta increases. However, changes in flow in patients with portal hypertension and healthy subjects are significantly different.

Wenjun Fan^1,2, Panli Zuo³, and Wen Shen^1
1Radiology, Tianjin First Center Hospital, Tianjin, Tianjin, China, ²Armed Police Corps Hospital of Henan, Zhengzhou, Henan, China, ³Siemens Healthcare, MR Collaborations NE Asia, Beijing, China

51 renal allograft recipients 2-3 weeks after transplantation and 26 healthy volunteers received 3.0T MR DTI examination. Patients were divided into three groups with good allograft function, moderately impaired allograft function and severely impaired allograft function according to the estimated glomerular filtration rate£®Apparent diffusion coefficient (ADC) and fractional anisotropy (FA) values were compared between groups with significant differences being found. A significant correlation between eGFR and medullary FA, cortical ADC and medullary ADC was also observed. Meanwhile, differences of DTI images and tractography demonstrated the potential of DTI to visually discriminate allograft with varied function.

Dagmar Hartung^1,2, Marcel Gutberlet^1,2, Frank Lehner^2,3, Nicolas Richter³, Nils Hanke⁴, Jan Becker^2,5, Matti Peperhove¹, Antonia Zapf⁶, Hermann Haller⁴, Frank Wacker¹, Wilfried Gwinner^2,4, and Katja Hueper^1,2
1Radiology, Hannover Medical School, Hannover, Germany, ²Integrated Research and Treatment Center Transplantation (IFB Tx), Hannover, Germany,³Transplantation Surgery, Hannover Medical School, Hannover, Germany, ⁴Nephrology, Hannover Medical School, Hannover, Germany, ⁵Pathology, Hannover Medical School, Hannover, Germany, ⁶Medical Statistics, University Goettingen, Goettingen, Germany

Delayed renal allograft function (DGF) is associated with an increased risk of graft complications. We investigated whether multiparametric functional MRI allows evaluation of DGF. Fourty patients between day 4-10 after kidney transplantation were examined using a 1.5T-scanner. Renal perfusion, apparent diffusion coefficients and fractional anisotropy were significantly reduced in patients with DGF compared to patients with normal initial graft function. Furthermore, functional MRI parameters were inversely correlated with serum creatinine at the day of MRI and at 3-months follow-up. Thus, multiparametric functional MRI may improve non-invasive diagnosis of DGF.

Andreas Pohlmann¹, Jan Hentschel¹, Karen Arakelyan¹, Kathleen Cantow², Bert Flemming², Mechthild Ladwig², Uwe Hoff³, Erdmann Seeliger², and Thoralf Niendorf^1
1Berlin Ultrahigh Field Facility, Max Delbrueck Center for Moleculare Medicine, Berlin, Germany, ²Institute of Physiology and Center for Cardiovascular Research, Charité Medical Faculty, Berlin, Germany, ³Nephrology and Intensive Care Medicine, Campus Virchow-Klinikum and Center for Cardiovascular Research, Charite-Universitaetsmedizin Berlin, Berlin, Germany

Acute kidney injuries of various origins share one common feature: imbalance between renal oxygen delivery and demand. T2* mapping offers a non-invasive approach to probe renal oxygenation. Changes in tissue pO2 and T2* may be closely related but for a physiological interpretation of T2* a calibration using an integrative approach that combines parametric MR with physiological measurements is prudent if not essential. This work employs an integrative hybrid approach that combines established invasive but quantitative techniques with a small animal MR system (MR-PHYSIOL) with the ultimate goal to detail the relation between tissue pO2 and T2* using (patho)physiologically relevant interventions.

Hans Hoogduin¹, Alexander Raaijmakers², Fredy Visser², and Peter Luijten^2
1UMC Utrecht, Utrecht, Utrecht, Netherlands, ²UMC Utrecht, Utrecht, Netherlands

BOLD imaging of the kidneys is explored at 7T.