Charlotte E Buchanan¹, Hao Li², Fabio Nery³, Alexander J Daniel¹, Joao De Sousa⁴, Steven Sourbron⁴, Andrew Priest^2,5, David Thomas^6,7,8, and Susan T Francis^1
1Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom, ²Department of Radiology, University of Cambridge, Cambridge, United Kingdom, ³Great Ormond Street Institute of Child Health, University College London, London, United Kingdom, ⁴University of Sheffield, Sheffield, United Kingdom, ⁵Department of Radiology, Addenbrooke's Hospital, Cambridge, United Kingdom, ⁶Neuroradiological Academic Unit, UCL Queen Square Institute of Neurology, UCL, London, United Kingdom, ⁷Dementia Research Centre, UCL Queen Square Institute of Neurology, UCL, London, United Kingdom, ⁸Wellcome Centre for Human Neuroimaging, UCL Queen Square Institute of Neurology, UCL, London, United Kingdom

Standardisation and multicentre evaluation of renal MRI measures is crucial for clinical translation. Here we present a multiparametric renal MRI protocol comprising of B₀ and B₁ mapping, diffusion weighted imaging (DWI), T₁, T₂ and T₂* mapping, phase contrast (PC-MRI) and volumetric T₁- and T₂-weighted scans that has been harmonised across GE, Philips and Siemens 3T scanners.

Charlotte E Buchanan¹, Rebecca Noble², Eleanor Cox¹, Huda E Mahmoud², Isma Kazmi², Benjamin Prestwich¹, Nicholas Selby², Maarten Taal², and Susan T Francis^1
1Sir Peter Mansfield Imaging Centre, University of Nottingham, Nottingham, United Kingdom, ²Centre for Kidney Research and Innovation, University of Nottingham, Derby, United Kingdom

We use multi-parametric renal MRI to assess structural and haemodynamic changes in CKD patients and assess these changes after one and two years to investigate the ability of MRI measures to predict and monitor progression of CKD. At baseline, higher renal cortex T₁ and a reduction in renal cortex perfusion are associated with subsequent progression of CKD over 2 years suggesting that these MRI parameters may be predictors of progression. Renal cortex T₁ and total kidney volume changed more in ‘progressors’  than in ‘stable’ participants over time compared to baseline suggesting these to be useful MRI measures to monitor progression.

Deep B. Gandhi¹, Jonathan R. Dillman², Andrew T. Trout², Jean A. Tkach², Prasad Devarajan³, and Stephanie W Benoit^4
1Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, ²Imaging Research Center, Department of Radiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, ³Department of Nephrology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States, ⁴Department off Nephrology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States

Multiparametric renal MRI might be used as a non-invasive biomarker of pediatric chronic kidney disease (CKD). 20 pediatric and young adult healthy controls and 12 patients with CKD underwent quantitative renal MRI consisting of MR elastography (MRE), T1 mapping, T2 mapping, and diffusion-weighted imaging (DWI). Whole kidney and cortical T1 values were greater in patients than healthy controls (p=0.018 and p<0.0001, respectively), whereas whole kidney, cortical, and medullary DWI ADC values were lower in patients than healthy controls (p=0.017, whole kidney). No differences in T2 or stiffness measurements between the two groups were observed.

Michael Pridmore¹, Maria Garza¹, Laura Jones², Cassandra Reynolds², Deepak Gupta², Manus Donahue¹, and Rachelle Crescenzi^1
1Radiology and Radiological Sciences, Vanderbilt University Medical Center, Nashville, TN, United States, ²Cardiovascular Medicine, Vanderbilt University Medical Center, Nashville, TN, United States

Salt sensitive blood pressure is a major independent risk factor for cardiovascular disease, with estimated 50% prevalence in adults for which no imaging biomarker exists. We evaluated persons for salt sensitivity and applied a quantitative magnetic resonance imaging strategy in the kidneys for measuring renal blood flow using free-breathing pseudo-continuous arterial spin labeling. Group comparisons showed renal blood flow is reduced in subjects with salt-sensitivity, which may be linked to renal mechanisms of sodium handling. Additionally, image acquisition protocols were compared between 20x and 4x acquisitions, revealing 4x acquisitions were robust to motion and favored a clinically feasible scan time.

Luke Xie¹, Aaron K Wong², Rohan S. Virgincar¹, Patrick Caplazi³, Vineela D. Gandham¹, Alex J. De Crespigny⁴, Robby M. Weimer¹, and Hans D. Brightbill^2
1Biomedical Imaging, Genentech, South San Francisco, CA, United States, ²Translational Immunology, Genentech, South San Francisco, CA, United States, ³Pathology, Genentech, South San Francisco, CA, United States, ⁴Clinical Imaging Group, Genentech, South San Francisco, CA, United States

Chronic kidney disease (CKD) is a significant global health problem with fibrosis being a common pathway of disease progression. While MRI is sensitive to fibrosis, the relationship to ultrastructural underpinnings is not well understood. In this study, we evaluate an oxalate induced CKD model and determine the correlation of MRI metrics with high-resolution terminal endpoints. We find that FA and AD in the medulla are most correlated with fibrosis pathologies, new hydroxyproline, and inflammatory and fibrotic gene expression. These results show that MRI can detect fibrosis and that the signal change is related to interstitial fibrosis and nephron ultrastructure.

Shubhangi Agarwal¹, Emilie Decavel-Bueff¹, Yung-Hua Wang¹, Hecong Qin¹, Romelyn Delos Santos¹, Michael Evans¹, and Renuka Sriram^1
1Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA, United States

There is a critical need for the development of non-invasive imaging strategies for tuberous sclerosis (TSC) derived tumor lesions in order to monitor the progression and therapeutic efficacy of this multi-system genetic disease. In this study, we investigated the ability of multiparametric ¹H MRI (morphological T₂-weighted and functional diffusion-weighted) to meet this need in a preclinical murine model of TSC treated with everolimus. Results indicated that proton MR imaging was able to capture the changes in cellularity and tumor size, post treatment.

Florian Schmid¹, Geogios Koukos¹, Yi Liu¹, Matt Sooknah¹, Sandip Chatterjee¹, Adam Freund¹, and Johannes Riegler^1
1Calico Life Sciences LLC, South San Francisco, CA, United States

We present an improved imaging and data analysis strategy for kidney MRI in mouse models of polycystic kidney disease. By registering multiple high resolution datasets at lower SNR, slow movement is compensated for and high resolution datasets with high quality and fine detail are achieved, allowing for detection and longitudinal tracking of kidney volume as well as cyst number and size. We established automatic cyst detection and are developing automatic kidney segmentation, for accurate and reliable assessment of polycystic kidney disease in mouse models.

Arun Joseph^1,2,3, Laila-Yasmin Mani⁴, Tom Hilbert^5,6,7, Thomas Benkert⁸, Tobias Kober^5,6,7, Bruno Vogt⁴, and Peter Vermathen^3
1Advanced Clinical Imaging Technology, Siemens Healthcare AG, Bern, Switzerland, ²Translational Imaging Center, Sitem-Insel, Bern, Switzerland, ³Departments of Radiology and Biomedical Research, University of Bern, Bern, Switzerland, ⁴Department of Nephrology and Hypertension, University Hospital Bern, Inselspital, Bern, Switzerland, ⁵Advanced Clinical Imaging Technology, Siemens Healthcare AG, Lausanne, Switzerland, ⁶Department of Radiology, Lausanne University Hospital and University of Lausanne, Lausanne, Switzerland, ⁷LTS5, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland, ⁸Application Predevelopment, Siemens Healthcare GmbH, Erlangen, Germany

Diffusion tensor imaging (DTI) of the kidney provides important functional information such as diffusion and micro-perfusion of the tissue and additionally estimates anisotropic diffusion of water in renal tubuli. However, these measurements are highly sensitive to respiration-induced motion artifacts which bias the obtained functional information. Here, we propose to use prospective acquisition motion correction (PACE) in combination with free-breathing acquisitions for motion-insensitive diffusion measurements of the kidney. A preliminary qualitative and quantitative validation is performed on healthy subjects comparing results from conventional respiratory-triggered to PACE-triggered DTI.

Manu Goyal¹, Junyu Guo¹, Lauren Hinojosa¹, Keith Hulsey¹, and Ivan Pedrosa^1
1Radiology, UT Southwestern Medical Center, Dallas, TX, United States

Automated segmentation of kidneys in Magnetic Resonance Imaging (MRI) exams are important for enabling radiomics and machine learning analysis of renal disease. In this work, we propose to use a deep learning method called Mask R-CNN for the segmentation of kidneys in 2D coronal T2W FSE images of 94 MRI exams. With 5-fold cross-validation data, the Mask R-CNN is trained and validated on 66 and 9 MRI exams and then evaluated on the remaining 19 exams. Our proposed method achieved an average dice score of 0.839 and an average IoU of 0.763.

Yiming Wang¹, Limin Zhou¹, Ivan Pedrosa^1,2,3, and Ananth J. Madhuranthakam^1,2
1Radiology, UT Southwestern Medical Center, Dallas, TX, United States, ²Advanced Imaging Research Center, UT Southwestern Medical Center, Dallas, TX, United States, ³Urology, UT Southwestern Medical Center, Dallas, TX, United States

3D Cartesian turbo spin echo (TSE) is a promising acquisition method for renal ASL because of its improved SNR and compatibility with optimal background suppression (BGS). However, 3D Cartesian TSE with single average can limit its SNR and robustness. In this study, we applied a variable density sampling approach to renal ASL imaging, which acquires the center of the k-space with higher signal averages and improves SNR and robustness without significantly prolonging scan time. We combined this with partial k-space acquired M0 images to compensate for increased scan time, but without compromising perfusion quantification.