Derk J. Slotman^1,2, Lambertus W. Bartels², Ingrid M. Nijholt¹, Edwin Heijman^3,4, Martijn Froeling², and Martijn F. Boomsma^1
1Radiology, Isala Zwolle, Zwolle, Netherlands, ²Image Sciences Institute, Imaging & Oncology Division, University Medical Center Utrecht, Utrecht, Netherlands, ³Faculty of Medicine and University Hospital of Cologne, Institute of Diagnostic and Interventional Radiology, University of Cologne, Cologne, Germany, ⁴High Tech Campus, Philips Research Eindhoven, Eindhoven, Netherlands

Blood volume fraction maps derived from diffusion weighted imaging using intravoxel incoherent motion (IVIM) modeling may be an alternative to contrast-enhanced imaging for visualization of local uterine fibroid perfusion, during magnetic resonance-guided high intensity focused ultrasound (MR-HIFU) ablation procedures. In this study, blood volume fraction maps calculated with a T2-corrected IVIM model were compared to T2-uncorrected parameter maps using two fitting techniques. Based on general inspection, T2-corrected parameter maps from deep learning-based fitting were visually the most appealing. A preliminary evaluation showed a linear association between NPVs delineated on blood volume fraction maps and gadolinium contrast-enhanced T1w scans.

Pierre Bour¹, Thibaut Faller¹, Valery Ozenne^2,3,4, Bruno Quesson^2,3, Max Seidensticker⁵, and Olaf Dietrich^5
1Certis Therapeutics, Pessac, France, ²INSERM, Centre de Recherche Cardio-Thoracique de Bordeaux, U1045, Bordeaux, France, ³IHU Liryc, Electrophysiology and Heart Modeling Institute, Hopital Xavier Arnozan, Pessac, France, ⁴UMR5536 CRMSB, Bordeaux, France, ⁵Department of Radiology, University Hospital, LMU Munich, Munich, Germany

Microwave tumor ablation in the liver is commonly performed in computed tomography scanners with limited imaging capability for real-time monitoring of treatment progression. Performing this procedure under MRI enables to monitor temperature and thermal dose during the ablation. It allows better understanding of the lesion creation and gives better insight of the treatment outcome. In this study, we evaluate a complete MR-guided workflow that include volumetric temperature and dose monitoring during ablation using an ultrafast EPI sequence with respiratory triggering. Results show that spatial extent of the lesion can be monitored and displayed in real-time.

C.S. de Jonge¹, C.A. Wagenaar^2,3, W. Walrabenstein^2,3, M.A. Troelstra¹, A.J. Nederveen¹, and D. van Schaardenburg^2,3
1Amsterdam UMC, University of Amsterdam, Department of Radiology and Nuclear Medicine, Amsterdam Gastroenterology Endocrinology Metabolism, Meibergdreef 9, Amsterdam, Netherlands, ²Amsterdam Rheumatology and Immunology Center, Reade, 1056 AB, Amsterdam, Netherlands, ³Amsterdam UMC, Amsterdam Medical Center, 1105 AZ, Amsterdam, Netherlands

The aim of this study was to evaluate the effect of a 16-week multidisciplinary lifestyle intervention with a plant-based diet on hepatocellular, intra- and extramyocellular lipid levels in patients with metabolic syndrome-associated osteoarthritis as measured by proton MR spectroscopy. The intervention group (n=17) was compared with the control group receiving usual care (n=15). At the end of the intervention the intervention group showed reduced hepatocellular lipid levels and total body fat mass and improved metabolic and inflammatory markers compared to the control group. There was no observable change of intra- and extramyocellular lipid levels.

Niek R.F. Huttinga¹, Tom Bruijnen¹, Cornelis A.T. van den Berg¹, and Alessandro Sbrizzi^1
1Department of Radiotherapy, Computational Imaging Group for MR therapy & Diagnostics, University Medical Center Utrecht, Utrecht, Netherlands

Respiratory motion during radiotherapy decreases the time-efficiency of treatments. The MR-Linac can potentially improve this with real-time 3D MR-based motion estimates. Ideally, these estimates should be accompanied with estimation uncertainty to ensure patient safety and spare organs-at-risk during bulk motion or breathing pattern change, but this is typically not provided by state-of-the-art methods. In this work we extend a previously proposed probabilistic framework for real-time motion and uncertainty estimation with a rejection criterion based on the estimation uncertainty. Results show that the proposed rejection criterion preserves low end-point-errors and rejects erroneous motion estimates during bulk motion and breathing pattern changes.

Marjola Thanaj¹, Nicolas Basty¹, Madeleine Cule², Elena P Sorokin², Jimmy David Bell¹, Elizabeth Louise Thomas¹, and Brandon Whitcher^1
1Research Centre for Optimal Health, School of Life Science, University of Westminster, London, United Kingdom, ²Calico Life Sciences LLC, South San Francisco, CA, United States

Organ MRI measurements have the potential to enhance our understanding of the precise phenotypic changes underlying many clinical conditions. Using liver mesh-based shape analysis we were able to detect significant changes in organ shape in specific anatomical regions associated with anthropometric traits and health conditions including type-2 diabetes and liver disease. We have shown that presence of T2D is associated with increase in liver shape and size. We also showed that the liver disease when accounting for liver fat showed more negative associations with the 3D liver shape phenotype.

Ilaria Neri¹, Carla Canevari¹, Elena Venturini², Francesca Gallivanone³, Samuele Ghezzo⁴, Carolina Bezzi^1,4, Rosa Di Micco⁵, Raffaele Menichini¹, Annarita Savi¹, Valentino Bettinardi¹, Maria Picchio^1,4, Oreste Gentilini⁵, Pietro Panizza², Luigi Gianolli¹, and Paola Scifo^1
1Nuclear Medicine, IRCCS San Raffaele Scientific Institute, Milan, Italy, ²Radiology, IRCCS San Raffaele Scientific Institute, Milan, Italy, ³Institute of Molecular Bioimaging and Physiology, National Research Council (IBFM-CNR), Milan, Italy, ⁴Vita-Salute San Raffaele University, Milan, Italy, ⁵Breast Surgery Unit, IRCCS San Raffaele Scientific Institute, Milan, Italy

This work investigates the correlations between PET/MR imaging parameters and histopathological factors of breast tumors extracted from image-guided biopsy. Results from our work show that PET and some MR parameters are statistically correlated to histopathological factors. Moreover, the integration of PET and MR (DCE-MR and ADC) parameters might help in the prediction of histopathological factors.

yu zhang¹, yun fei zha¹, and Weiyin Vivian Liu^2
1Renmin Hospital of Wuhan University, wu han, China, ²GE Healthcare, Beijing, China

Increasing evidence has suggested that endoscopic retrograde cholangiopancreatography (ERCP) in the supine position is technically more technically demanding for operators than prone ERCP and leads to a greater risk of adverse cardiorespiratory events. Our results showed no differences in the CR, SNR, and CNR of the CBD between MRCP image sets. The visibility of most pancreaticobiliary ducts, motion artifact, and overall image quality were slightly better on the prone MRCP images than on the supine ones (P < 0.005). Therefore, 3D prone MRCP could provide better visualization and a roadmap directly matched with prone ERCPs for clinicians performing a surgery. 

Robert Carson Sibley¹, James P. Yoon¹, and Andreas M. Loening^1
1Stanford University, Stanford, CA, United States

Given the dearth of quantitative metrics for staging lymphedema, we assessed subcutaneous and muscle tissue imaging metrics for patients with lower extremity lymphedema. Subcutaneous and muscle tissue thickness, subcutaneous thickness fraction (subcutaneous /sum of subcutaneous and muscle tissue thickness), and subcutaneous area fraction (subcutaneous / sum of subcutaneous and muscle tissue area) were measured. Leg subcutaneous measures strongly and significantly correlated with International Society of Lymphology lymphedema stage, while thigh subcutaneous measures demonstrated a trend to moderate correlation with stage. As lymphedema typically progresses from the distal to proximal extremity, the greater correlation with the leg is expected.

Jitka Starekova¹, Alexandra A Acher^1,2, Frank A Thornton³, and Scott B Reeder^1,4,5,6,7
1Radiology, University of Wisconsin-Madison, Madison, WI, United States, ²Surgery, University of Utah, Salt Lake City, Salt Lake City, UT, United States, ³University of Wisconsin-Madison, Madison, WI, United States, ⁴Engineering, University of Wisconsin-Madison, Madison, WI, United States, ⁵Medical Physics, University of Wisconsin-Madison, Madison, WI, United States, ⁶Medicine, University of Wisconsin-Madison, Madison, WI, United States, ⁷Emergency Medicine, University of Wisconsin-Madison, Madison, WI, United States

The growing need for liver transplantation has led to an increased need for living liver donors. Partial hepatectomy in donors carries significant risk, requiring rigorous preoperative evaluation. Contrast-enhanced MRI and MR cholangiography can assess liver lesions and biliary variants, while chemical shift-encoded MRI and MR elastography detect and quantify fat, iron and fibrosis in unexpected diffuse liver disease. This study summarizes our experience with an extended MRI protocol in 68 potential donors.  MRI, in isolation or in combination with other test results identified more than half of patients at risk for surgical complications of liver donation. 

Robert Carson Sibley¹, Maxim A. Moroz¹, Shreyas S. Vasanawala¹, and Andreas M. Loening^1
1Stanford University, Stanford, CA, United States

MR lymphangiography (MRL) utilizing the clinically available small molecular weight gadolinium contrast agents suffers from diffusion of contrast out of the lymphatic system and into the blood pool. We describe a modified MRL technique where a clinically available iron oxide nanoparticle (ferumoxytol) is used as the lymphatic contrast agent. The higher molecular weight of these nanoparticles results in retention of contrast within the lymphatic system. This simplifies peripheral lymphatic imaging by eliminating the need for vascular contamination suppression techniques and should allow better tracking of contrast through the central lymphatics following pedal injections.

Robert Carson Sibley¹ and Andreas M. Loening^1
1Stanford University, Stanford, CA, United States

This retrospective cross-sectional study assessed different methods for staging lymphedema on Dual Agent Relaxivity Contrast MR Lymphangiography (DARC-MRL). Images from 20 patients (40 limbs) with clinically diagnosed and staged lower extremity lymphedema who had undergone DARC-MRL were assessed for dermal backflow, lymphatic vessel enhancement, and subcutaneous edema, in six regions of the lower limbs. These assessments were translated into a dermal backflow score and an edema score of our own design, as well as a recently published MRL Stage (Soga et al. 2021). All three scores demonstrated strong to excellent correlation with International Society of Lymphology (ISL) clinical stages.

Martin Dawson Holland¹, David A Hormuth², Xiaoyu Jiang³, Chase D Christenson⁴, Desiree E Morgan⁵, Yufeng Li⁵, Junzhong Xu³, Thomas E Yankeelov⁴, and Harrison Kim^5
1Medicine, University of Alabama at Birmingham, Birmingham, AL, United States, ²The University of Texas at Austin, Austin, TX, United States, ³Vanderbilt University, Nashville, TN, United States, ⁴University of Texas at Austin, Austin, TX, United States, ⁵University of Alabama at Birmingham, Birmingham, AL, United States

Shutter Speed Model (SSM) based Ktrans, ve, kep, and τi in the pancreatic tumors before initiating chemotherapyt were 0.081±0.036 mm-1, 0.258±0.070, 0.320±0.152 mm-1, and 0.247±0.197 μs, respectively, without statistical difference between the responding and non-responding groups.  The Ktrans in the tumors favorably responding to chemotherapy increased 72±14%, significantly larger than in the non-responding tumors (2±9%, p=0.0001).  The ve in the responding tumors also significantly increased compared to the non-responding group (64±25% vs 3±9%, p=0.0036).  However, no statistical difference was found between the responding and non-responding groups in either kep (6±11% vs 11±16%, p=0.6204) or τi (3±47% vs 147±280%, p=0.3408).

Nana Owusu¹, Zheng Zhu¹, Jiahui Li¹, Kevin Glaser¹, Yi Sui¹, Douglas Simonetto², Patrick Kamath², Vijay Shah², Sudhakar Venkatesh³, Richard Ehman¹, and Meng Yin^1
1Radiology, Mayo Clinic, Rochester, MN, United States, ²Gastroenterology, Mayo Clinic, Rochester, MN, United States, ³Mayo Clinic, Rochester, MN, United States

An efficient imaging protocol was developed to facilitate diagnosis of hepatorenal syndrome in patients with decompensated cirrhosis. Multiparametric MRI for quantifying perfusion, diffusion, and blood oxygenation, as well as multiparametric MRE for quantifying viscoelasticity and tissue pressure were optimized in preparation for the pilot study predicting hepatorenal syndrome. Results demonstrate the feasibility of the multiparametric protocol and provide motivation for commencing clinical testing.

Paul E Summers¹, Alessia Minchillo², Sarah Alessi¹, Giuseppe Renne³, Ottavio De Cobelli^4,5, Gennaro Musi^4,5, Giulia Marvaso^4,6, Barbara Alicja Jereczek-Fossa^4,6, and Giuseppe Petralia^4,7
1Division of Radiology, IEO, European Institute of Oncology IRCCS, Milano, Italy, ²University of Milan, Milano, Italy, ³Uropathology and Intraoperative Diagnostics, IEO, European Institute of Oncology IRCCS, Milano, Italy, ⁴Department of Oncology and Hemato-oncology, University of Milan, Milano, Italy, ⁵Division of Urology, IEO, European Institute of Oncology IRCCS, Milano, Italy, ⁶Division of Radiation Oncology, IEO, European Institute of Oncology IRCCS, Milano, Italy, ⁷Precision Imaging and Research Unit, IEO, European Institute of Oncology IRCCS, Milano, Italy

We hypothesized that the presence of asymmetry in the arterial supply of the prostate may provide a correlate of extra-prostatic tumor extension in patients with prostate cancer. In this preliminary study of 40 patients (20 with and 20 without extra-prostatic disease), a radiologist blind to the status of the patients, made a binary choice as to the presence or absence of peri-prostatic vascular asymmetry. Taking the pathological grading as the reference standard, the sensitivity, specificity, positive and negative predictive values were all 0.9. The negative likelihood ratio (LR-) was 0.11, and the positive likelihood ratio (LR+) was 9.0.

Nienke S. de Jager¹, Tim J. van Oostenbrugge², Torben Pätz³, Sjoerd F.M. Jenniskens¹, Jurgen J. Fütterer¹, Hans Langenhuijsen², and Christiaan G. Overduin^1
1Medical Imaging, Radboudumc, Nijmegen, Netherlands, ²Urology, Radboudumc, Nijmegen, Netherlands, ³Fraunhofer Institute for Digital Medicine, Bremen, Germany

MRI-guided cryoablation of small renal tumors relies on achieving sufficient ice ball coverage throughout the entire lesion for effective treatment. However, a volumetric approach to assess treatment margins intraoperatively is currently lacking. This work retrospectively derived three-dimensional ablation margins after cryoablation in 39 kidney tumors using co-registration of intraoperatively acquired pre- and post-ablation MR images. Minimal ablation margins were significantly smaller for cases with versus without local tumor progression. Radiological complete coverage (ablation margin >0 mm) was associated with local control. MRI-derived 3D ablation margins may present a useful intraprocedural tool to assess treatment success.