Jing Wang¹, Yudong Zhang², Xuedong Yang², Xiaoying Wang², Jue Zhang^1,3, and Jing Fang^1,3
1Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China, ²Department of Radiology, Peking University First Hospital, Beijing, China, ³College of Engineering, Peking University, Beijing, China

Contrast media is associated with several adverse effects, including contrast-induced nephropathy. We utilized noninvasive ASL and BOLD MRI to evaluate the serial effects of intravenous-injected iodinated CM on rabbit renal hemodynamics and oxygenation. Both FAIR-ASL and multiple-echo SPGR sequences were performed 24 hours before and 1, 24, 48 and 72 hours after injection to obtain serial renal blood flow and relative spin-spin relaxation rate (R2*). Iopamidol is associated with a relatively longer-term hypoperfusion in whole kidney and decreased oxygen level in the inner stripes of the outer medulla.

Raffi Kalayciyan¹, Friedrich Wetterling¹, Sabine Neudecker², Norbert Gretz², and Lothar R. Schad^1
1Computer Assisted Clinical Medicine, Heidelberg University, Mannheim, Germany, ²Medical Research Center, Heidelberg University, Mannheim, Germany

Since renal function is highly correlated with renal tissue 23Na concentration, 23Na-Kidney-MRI can be used to monitor the spatial changes in 23Na along the corticomedullary axis after diuretics administration. Furthermore, the temporal changes in the medulla and cortex 23Na signals could be studied, if sufficient spatial and temporal resolution can be achieved. The aim of this study was to measure the temporal 23Na signal before and after furosemide-injection in four rats via bilateral renal 23Na-MRI (n=8). In order to maximize 23Na signal at 9.4 T, a 3D-Ultrashort Echo Time (3D-UTE) sequence was used in conjunction with a home-built transceiver surface resonator.

Lingzhi Hu¹, Junjie Chen¹, Xiaoxia Yang¹, Shelton D. Caruthers¹, Gregory M. Lanza¹, and Samuel A. Wickline^1
1Washington University School of Medicine, saint louis, MO, United States

We have demonstrated a new 19F MRI approach using circulating PFC NP to quantify renal perfusion and vascular damage after ischemic injury. The measured regional intrarenal blood volume and oxygenation is consistent with previous observations. In I/R injured kidney, 19F MRI of PFC NP delineates reduced blood volume in C-M junction and vascular leakage in medulla as a consequence of endothelial damage. Although BOLD MRI shows enhanced T2* values at C-M junction of injured kidneys, it does not necessarily reflect hyperoxia but may also sense reduced blood flow. Thus, the proposed novel 19F MRI approach could provide a powerful tool to assess renal vascular damage in AKI.

Zohar Milman¹, Jonathan Axelrod¹, Samuel Heyman², Nathalie Corchia-Nachmanson¹, and Rinat Abramovitch^1
1The Goldyne Savad Institute of Gene Therapy, Hadassah Hebrew University Medical Center, Jerusalem, Israel, ²Department of Medicine, Hadassah Hebrew University Medical Center, Jerusalem, Israel

The use of MRI for the diagnosis of acute and chronic kidney diseases is expanding; however, contrast-enhanced methods are limited due to adverse effects. We studied the feasibility of two MRI-methods: (1) HRI, based on BOLD fMRI, combined with hypercapnic and hyperoxic challenges, for monitoring changes in kidney perfusion, and (2) True-FISP, for monitoring changes in renal morphology, during CKD and AKI progression in mice. True-FISP images revealed clear differences in CKD compared to AKI. HRI maps revealed significantly reduced renal perfusion in both CKD and AKI. Together, these methods may assist in the differentiation and characterization of renal pathologies.

Katja Hueper¹, Dagmar Hartung¹, Marcel Gutberlet¹, Faikah Gueler², Holger Sann³, Bettina Husen³, Frank Wacker¹, and Dania Reiche^3
1Radiology, Hannover Medical School, Hannover, Germany, ²Nephrology, Hannover Medical School, Hannover, Germany, ³Abbott Products GmbH, Hannover, Germany

We investigated whether MR BOLD and diffusion tensor imaging (DTI) enables detection of renal pathologies in a rat model of diabetic nephropathy. Twenty-one rats (control; diabetes; diabetes with uninephrectomy, DM UNX) were examined by BOLD and echoplanar DTI (1.5T, b=0, 300 s/mm2, 6 diffusion directions). T2*-values, Fractional Anisotropy (FA) and ADC were compared to laboratory parameters and histology. T2*-values were not different between groups. However, in kidneys of DM UNX rats FA was significantly reduced and inversely correlated with glomerulosclerosis, interstitial fibrosis and tubular damage. Thus, MR DTI might be useful to noninvasively identify and monitor renal impairment in diabetes.

David J Niles¹, Nathan S Artz¹, Elizabeth A Sadowski², Arjang Djamali³, Thomas M Grist^1,2, and Sean B Fain^1,2
1Medical Physics, University of Wisconsin, Madison, WI, United States, ²Radiology, University of Wisconsin, Madison, WI, United States, ³Medicine, University of Wisconsin, Madison, WI, United States

Routine monitoring of renal function following transplantation is important for early detection of disease. In this study we used BOLD and ASL MRI to measure renal oxygenation and perfusion, respectively, in matched pairs of kidney transplant donors and recipients up to two years following transplantation. Statistically significant decreases in cortical perfusion and medullary oxygenation were observed in transplanted kidneys 3 months post-transplantation and remained present one year post-transplantation. Further measurements in this ongoing study will be used to statistically assess function two years post-transplantation.

Luke Xie^1,2, Wei Li³, Matthew Sparks⁴, Yi Qi², Gary P. Cofer², Thomas Coffman⁴, G. A. Johnson^1,2, and Chunlei Liu^2,3
1Biomedical Engineering, Duke University, Durham, NC, United States, ²Center for In Vivo Microscopy, Duke University Medical Center, Durham, NC, United States, ³Radiology, Duke University Medical Center, Durham, NC, United States, ⁴Nephrology, Duke University Medical Center, Durham, NC, United States

This study utilizes the first renal susceptibility imaging on altered kidneys in mice lacking angiotensin II receptor AT1A or both AT1A and AT1B receptors. Kidneys were imaged using a GRE sequence at 9.4 T and susceptibility values were measured in cortex, outer medulla, and inner medulla for comparison in wild type (WT), AT1a -/- (A), and AT1a -/- AT1b -/- (AB) mice. AB kidneys exhibited interstitial fibrosis, tubular atrophy, and arterial thickening, which changed the spatial distribution of paramagnetic contrast for magnetic susceptibility. AB kidneys exhibited low contrast regions/vessels, higher susceptibility, and broader distribution compared to WT or A kidneys.

Rado Andriantsimiavona¹, Dow-Mu Koh¹, David Collins¹, Simon Doran¹, and Martin Leach^1
1Institute of Cancer Research UK, Sutton, London, United Kingdom

We have developed an interactive framework that allows spatially synchronised 3D visualisation and analysis of anatomical, diffusion-weighted and dynamic contrast enhanced MR data in multi-planar orientations and used it to establish correlations between parametric maps derived from MRI (ADC and AUC) and the corresponding characteristics measured from paired histological sections. Our aim is to provide biologically meaningful interpretations of multiparametric analysis as well as build a computer aided tissue classification scheme for the RCC model.

Mike Notohamiprodjo¹, Michael Staehler², Nicole Steiner¹, Felix Schwab³, Steven P Sourbron⁴, Henrik J Michaely⁵, Maximilian F Reiser¹, and Konstantin Nikolaou^1
1Department of Clinical Radiology, University Hospitals Munich, Munich, Bavaria, Germany, ²Clinic for Urology, University Hospitals Munich, ³Department of Clinical Radiology, Josef Lissner Institute for Biomedical Imaging, University Hospitals Munich, Munich, Bavaria, Germany, ⁴Medical Physics, University of Leeds, ⁵Department of Clinical Radiology and Nuclear Medicine, University Hospital Mannheim

Multiple MR-techniques for functional tumor evaluation are available, however correlation of these techniques has not been investigated. A protocol comprising Diffusion weighted Imaging (DWI), Blood oxygen level dependent (BOLD) and Dynamic contrast enhanced (DCE)-MRI is feasible for assessment of primary RCC. BOLD moderately correlates to perfusion derived from DCE-MRI. ADC shows moderate correlation to the extracellular volume, but does not correlate to tumor oxygenation or perfusion as it provides mixed information on both perfusion and cellularity. IVIM analysis may resolve this ambiguity. Tumor permeability does not correlate to any other functional parameter.