Dee Zhen Lim¹, Julia Williams¹, Jason Wong¹, Lucy McKenna¹, Julie Smith¹, Emma Hornsey¹, Dominic Italiano², Leonid Churilov², Daniel Staeb³, Thomas Benkert⁴, Elif Ekinci^5,6, and Ruth P Lim^1,7
1Department of Radiology, Austin Health, Heidelberg, Australia, ²Melbourne Medical School, University of Melbourne, Melbourne, Australia, ³MR Research Collaborations, Siemens Healthcare Pty Ltd, Melbourne, Australia, ⁴MR Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany, ⁵Department of Endocrinology, Austin Health, Heidelberg, Australia, ⁶Department of Medicine, University of Melbourne, Melbourne, Australia, ⁷Departments of Radiology and Surgery, University of Melbourne, Melbourne, Australia

Renal diffusion tensor imaging (DTI) is a promising, non-invasive biomarker for kidney function. Cortical and medullary fractional anisotropy (FA) and mean diffusivity (MD) correlates with early microstructural and functional changes in kidney diseases. However, reliability of DTI metrics is affected by artifacts. The ideal renal DTI sequence for robust and reproducible measurements remains under investigation. We report on a prototype for small field-of-view (FOV) DTI incorporating 2D selective and rotated RF excitation and automatic motion correction to minimize artifacts in 9 diabetic patients and 9 controls, demonstrating high inter-reader agreement for measured FA and MD and high image quality. 

Joao Periquito¹, Kanishka Sharma¹, Bashair Alhummiany², Joao Sousa¹, and Steven Sourbron^1
1The University of Sheffield, Sheffield, United Kingdom, ²University of Leeds, Leeds, United Kingdom

A recent consensus paper recommends a mono-exponential signal model to determine T₂-values from a T₂-preparation sequence. However, this assumes complete signal recovery after each readout, and therefore necessitates long acquisition times. In this study, we compare the mono-exponential model against a forward modelling approach which is also accurate with incomplete recovery. Simulations, phantom data and repeatability data in healthy volunteers show the forward model is significantly more accurate and allows for a 7-fold reduction in acquisition time with a negligible cost in T₂ precision.

Julia Stabinska^1,2,3, Helge Jörn Zöllner^1,2, Hans-Jörg Wittsack³, and Alexandra Ljimani^3
1F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Institute, Baltimore, MD, United States, ²The Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, United States, ³Department of Diagnostic and Interventional Radiology, Heinrich Heine University Dusseldorf, Dusseldorf, Germany

Recent studies have shown that a three-compartment model is preferable when analyzing renal DWI signal, as the conventional bi-exponential IVIM fitting does not differentiate between pure water diffusion and incoherent intra-tubular fluid motion. However, triexponential IVIM modelling in the kidney is challenging due to suboptimal SNR of diffusion-weighted images. In the present study, we applied Image Downsampling Expedited Adaptive Least-squared (IDEAL) fitting, which utilizes image downsampling to generate high SNR images to iteratively update the initial model parameters until the final image resolution is reached, and achieved more reliable estimates of the IVIM-related parameters compared with the conventional fitting methods.

Edwin J. Baldelomar¹, Jennifer Charlton², and Kevin M Bennett^3
1Radiology, Washington University in St. Louis School of Medicine, St. Louis, MO, United States, ²Pediatric Nephrology, University of Virginia, Charlottesville, VA, United States, ³Radiology, Washington University in St. Louis School of Medicine, Saint Louis, MO, United States

Nephrons are the functional units of the kidney, coordinated with surrounding nephrons through the vasculature to filter blood plasma. We used in vitro CFE-MRI combined with Gd-DTPA contrast enhanced MRI to dynamically map single nephron physiology throughout the isolated, perfused rat kidney. We were able to map the heterogeneity and spatial variability of macromolecular binding and single nephron filtration. MRI appears to measure similar dynamics in single nephron filtration as intra-vital optical microscopy, with the advantage of measuring all nephrons in the kidney.

Shimrit Avraham¹, Rohan Virgincar², Joshua Webster³, Andrey Shaw¹, and Luke Xie^2
1Research Biology, Genentech, South San Francisco, CA, United States, ²Biomedical Imaging, Genentech, South San Francisco, CA, United States, ³Research Pathology, Genentech, South San Francisco, CA, United States

Accurate estimation of kidney function is crucial to the detection, evaluation, and treatment of chronic kidney disease (CKD). The traditional methods are inaccurate or invasive. Here, we used DTI-MRI to evaluate kidney function with disease progression in nephrotoxic serum- induced CKD model (NTN). We detect changes associated with renal inflammation and fibrosis prior to functional decline. Moreover, AD and ADC of the cortex-outer medulla border were highly correlated with histologic evidence of fibrosis. These results suggest that DTI-MRI can detect early stages of CKD non-invasively in-vivo and can be used for fibrosis mapping in a variety of renal diseases.

Lu-Ping Li^1,2, Emily Wilt¹, Artem Mikheev³, Henry Rusinek³, Stuart Sprague^1,2, Orly Kohn², and Pottumarthi Prasad^1,2
1NorthShore University HealthSystem, Evanston, IL, United States, ²Pritzker School of Medicine, University of Chicago, Chicago, IL, United States, ³Langone School of Medicine, New York University School of Medicine, New York, NY, United States

While regions of interest analysis is widely used in quantitative MRI, emphasis usually is placed only on the spatial average and information of spatial heterogeneity is ignored.  Texture analysis has gained increasing interest in the context of applying artificial intelligence.  These Radiomic tools are now readily available in image analysis tool boxes for more widespread adoption.  We illustrate an application of such analysis on quantitative renal MRI, including ADC, ASL and R2* maps. Our results show that several measures of heterogeneity of cortical voxel-wise maps  discriminate  between healthy and individuals with chronic kidney disease.  

Penny L Hubbard Cristinacce¹, Franziska Lausecker², Shanshan Li², Ben R Dickie^3,4, Michael Berks¹, Ross A Little¹, Alastair Hutchison^5,6, James PB O'Connor^1,7, and Rachel Lennon^2
1Division of Cancer Sciences, The University of Manchester, Manchester, United Kingdom, ²Division of Cell-Matrix Biology and Regenerative Medicine, The University of Manchester, Manchester, United Kingdom, ³Division of Informatics, Imaging and Data Science, The University of Manchester, Manchester, United Kingdom, ⁴Geoffrey Jefferson Brain Research Centre , Manchester Academic Health Science Centre, Northern Care Alliance & University of Manchester, Manchester, United Kingdom, ⁵Division of Cardiovascular Sciences, The University of Manchester, Manchester, United Kingdom, ⁶Dorset Count Hospital NHS Foundation Trust, Dorset, United Kingdom, ⁷Division of Radiotherapy and Imaging, Institute of Cancer Research, London, United Kingdom

Compensatory hypertrophy of the remaining kidney is observed in mice after nephrectomy using structural MRI. By fitting the two-compartment filtration model to dynamic contrast-enhanced MRI data we examined the effects of nephrectomy on the passage of blood through the remaining kidney over time. Total kidney plasma volume (v_p) increases at 1 week post-nephrectomy, along with T₁. This is followed by a decrease at week 4, which is coupled to a decrease in total and per unit volume plasma flow and an increase in plasma mean transit time. 

Sean McTavish¹, Anh T. Van¹, Johannes M. Peeters², Kilian Weiss³, Marcus R. Makowski¹, Rickmer F. Braren¹, and Dimitrios C. Karampinos^1
1Department of Diagnostic and Interventional Radiology, Technical University of Munich, Munich, Germany, ²Philips Healthcare, Best, Netherlands, ³Philips GmbH Market DACH, Hamburg, Germany

Diffusion-weighted imaging (DWI) and ADC mapping remains a potential biomarker for the assessment of renal fibrosis in chronic kidney disease and characterization of renal carcinoma. However, for body DWI applications including renal DWI, motion effects can confound the robustness of abdominal DWI. Motion-compensated diffusion encoding designs have been proposed as alternatives in overcoming the effect motion in other organs such as the liver and the pancreas. The purpose of this work is to assess the effect of respiratory motion and to apply motion compensated diffusion encoding waveforms in the context of coronal respiratory-triggered ADC mapping in the kidney.

Fangjie Xia^1,2, Wen Shen³, Lihua Chen³, and Jinxia Zhu^4
1Tianjin First Center Hospital, Tianjin medical university, Tianjin, China, ²Tianjin medical university, Tianjin, China, ³Tianjin First Center Hospital, Tianjin, China, ⁴Siemens Healthcare, Beijing, China

The study use Dixon and DKI sequence to quantitative analysis the ectopic fat deposition in chronic kidney disease and diabetic nephropathy. Compare the degree of fat infiltration in different organs and tissues including Liver, pancreas, kidney and muscles, combined with clinical laboratory experiments, to study the relationship between fat deposition and the development of CKD or diabetic nephropathy. Aim to point out the significance of treatment to fat deposition for CKD or diabetic nephropathy patient.

Irène Brumer¹, Dominik F. Bauer¹, Lothar R. Schad¹, and Frank G. Zöllner^1
1Computer Assisted Clinicial Medicine, Mannheim Institute for Intelligent Systems in Medicine, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany

Synthetic kidney ASL data with respiratory motion was generated using models from the XCAT phantom and matching recommendations for in-vivo acquisitions. Both pCASL and PASL datasets with 1 M0 and 25 control-label pairs were created and analysed using an in-house developed processing pipeline including registration, manual segmentation, calculation of mean perfusion-weighted image and perfusion map. The registration performed well on the synthetic data and the perfusion maps yielded good cortex/medulla contrast. The presented method allows a wide range of parameter choices for creating synthetic ASL datasets valuable for testing processing pipelines and comparing them across research and clinical imaging centres.

Ehsan Tasbihi¹, Luis Hummel², Thomas Gladytz¹, Ludger Starke¹, Jason M. Millward¹, Erdmann Seeliger², and Thoralf Niendorf^1,3
1Berlin Ultrahigh Field Facility (B.U.F.F.), Max Delbrueck Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, Berlin, Germany, ²Institute of Vegetative Physiology, Charité – Universitätsmedizin Berlin, Berlin, Germany, Berlin, Germany, ³Experimental and Clinical Research Center, a joint cooperation between the Charité Medical Faculty and the MAX Delbrück Center for Molecular Medicine in the Helmholtz Association, Berlin, Germany, Berlin, Germany

Accumulation of gadolinium (Gd) following use of Gd-based contrast agents (GBCA) is a concern. To study the potential of T₁ microscopy for assessing Gd residues in the kidney, rats were administered 8 intravenous doses of various GBCAs over a period of two weeks. Five days following the last administration, the kidneys were collected and fixed in formalin. High resolution T₁ maps obtained from ex vivo scans showed significantly reduced T₁ levels for both linear and macrocyclic GBCAs. This demonstrates to potential for quantitative T₁  mapping to detect Gd residues non-invasively in renal tissue.

Akira Yamamoto¹, Tsutomu Tamada², Yu Ueda³, Mitsuru Takeuchi⁴, Ayumu Kido², Atsushi Higaki², and Akihiko Kanki^2
1Radiology, Kawasaki Medical School, Kurashiki, Japan, ²Kawasaki Medical School, Kurashiki, Japan, ³Phillips Japan, Tokyo, Japan, ⁴Radiolonet Tokai, Nagoya, Japan

The purpose of this study was to identify the changes in multiparametric magnetic resonance imaging (MRI) findings in early diabetic nephropathy (DN). Multiparametric measurements were made of the renal cortex and medulla. Significant differences were seen between the healthy and early DN (grade1) in optimal TI and inverted TI value. T2 value of cortex is in marginal significant (p=0.064). This study suggests the possibility that MRI using the values of optimal TI, inverted TI value and T2 value of cortex can be used to evaluate early diabetic nephropathy non-invasively and in a short period of time.

Stephan Rodrigo Marticorena Garcia¹, Frank Friederdorff², Josef Mang², Alexandra Webster¹, Bernd Hamm¹, Jürgen Braun³, and Ingolf Sack^1
1Radiology, Charité – Universitätsmedizin Berlin, Berlin, Germany, ²Urology, Charité – Universitätsmedizin Berlin, Berlin, Germany, ³Medical Informatics, Charité – Universitätsmedizin Berlin, Berlin, Germany

Renal stiffness was investigated by using magnetic resonance elastography (MRE) with tomoelastography-postprocessing in 24 participants (12 renal donor-recipient couples) to explore the influence of kidney transplantation on renal viscoelasticity for the first time. Renal stiffness increases immediately after transplantation. These early changes could be due to changes in renal perfusion and increase in renal metabolism, which is also reflected by increase in renal volume. Cold ischemia time was found in being a contributor to changes of solid renal structures. Inccrease in renal stiffness after transplantation could be a novel predictive biomarker for better renal outcome.

Shan Jiayuan¹, Zhang Jinggang¹, Chen Jie¹, Xing Wei¹, Wang Yishi², and Zhang Jilei^3
1Third Affiliated Hospital of Soochow University, Changzhou, China, China, ²Philips Healthcare, Beijing, China, ³Philips Healthcare, Shanghai, China

To explore the value of quantitative susceptibility mapping (QSM) in evaluating renal injury in patients with chronic kidney disease (CKD). 40 CKD patients were included in the study to evaluate the potential clinical value of QSM. We found that with the progress of CKD staging, renal medulla susceptibility values decreased significantly. Susceptibility value of the medulla was highly correlated with estimated glomerular filtration rate (eGFR). QSM could serve as a quantitative biomarker to assess the renal injury of early CKD.

Seiya Nakagawa¹, Tosiaki Miyati¹, Naoki Ohno¹, Koga Kawano¹, Yuki Oda¹, and Satoshi Kobayashi^1
1Division of Health Sciences, Graduate School of Medical Sciences, Kanazawa University, Kanazawa, Ishikawa, Japan

We assessed the effect of posture on kidney volume measured in the supine and upright positions using an original MRI system that can image in any posture (multiposture MRI). We compared the kidney volume (whole kidney, renal cortex, medulla, and pelvis) between the supine and upright positions. Upright position reduced whole kidney, renal cortex, and medulla volumes, and these differences between postures potentially provide new diagnostic information.