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256 results on '"Kolipaka, Arunark"'

3. Magnetic resonance imaging as a non-invasive method for the assessment of pancreatic fibrosis (MINIMAP): a comprehensive study design from the consortium for the study of chronic pancreatitis, diabetes, and pancreatic cancer

Author

Tirkes, Temel, Yadav, Dhiraj, Conwell, Darwin L, Territo, Paul R, Zhao, Xuandong, Venkatesh, Sudhakar K, Kolipaka, Arunark, Li, Liang, Pisegna, Joseph R, Pandol, Stephen J, Park, Walter G, Topazian, Mark, Serrano, Jose, and Fogel, Evan L

Subjects
Biomedical and Clinical Sciences, Clinical Sciences, Rare Diseases, Bioengineering, Biomedical Imaging, Cancer, Clinical Research, Digestive Diseases, Pancreatic Cancer, 4.2 Evaluation of markers and technologies, 4.1 Discovery and preclinical testing of markers and technologies, Detection, screening and diagnosis, Oral and gastrointestinal, Chronic Disease, Fibrosis, Humans, Magnetic Resonance Imaging, Multicenter Studies as Topic, Pancreatitis, United States, Chronic pancreatitis, MRI, MRCP, T-1 mapping, Extracellular volume, Diffusion-weighted imaging, MR elastography, Consortium for the Study of Chronic Pancreatitis, Diabetes, and Pancreatic Cancer, T 1 mapping, Nuclear Medicine & Medical Imaging, Clinical sciences
Abstract

Characteristic features of chronic pancreatitis (CP) may be absent on standard imaging studies. Quantitative Magnetic Resonance Imaging (MRI) techniques such as T1 mapping, extracellular volume (ECV) fraction, diffusion-weighted imaging (DWI) with apparent diffusion coefficient map (ADC), MR elastography (MRE), and T1-weighted signal intensity ratio (SIR) have shown promise for the diagnosis and grading severity of CP. However, radiologists still use the Cambridge classification which is based on traditional ductal imaging alone. There is an urgent need to develop new diagnostic criteria that incorporate both parenchymal and ductal features of CP seen by MRI/MRCP. Designed to fulfill this clinical need, we present the MINIMAP study, which was funded in September 2018 by the National Institutes of Health. This is a comprehensive quantitative MR imaging study which will be performed at multiple institutions in well-phenotyped CP patient cohorts. We hypothesize that quantitative MRI/MRCP features can serve as valuable non-invasive imaging biomarkers to detect and grade CP. We will evaluate the role of T1 relaxometry, ECV, T1-weighted gradient echo SIR, MRE, arteriovenous enhancement ratio, ADC, pancreas volume/atrophy, pancreatic fat fraction, ductal features, and pancreatic exocrine output following secretin stimulation in the assessment of CP. We will attempt to generate a multi-parametric pancreatic tissue fibrosis (PTF) scoring system. We anticipate that a quantitative scoring system may serve as a biomarker of pancreatic fibrosis; hence this imaging technique can be used in clinical practice as well as clinical trials to evaluate the efficacy of agents which may slow the progression or reverse measures of CP.

Published
2019

8. Contributors

Author

Akyildiz, Ali C., primary, Antoniadis, Antonios P., additional, Athanasiou, Lambros S., additional, Barrett, Hilary E., additional, Billiar, Kristen, additional, Canet Soulas, Emmanuelle, additional, Cardoso, Luis, additional, Cawthon, Claire, additional, Chatzizisis, Yiannis S., additional, Chiastra, Claudio, additional, Cilla, Myriam, additional, Cloutier, Guy, additional, Coppel, Ricardo, additional, Demos, Catherine, additional, Dérimay, François, additional, Dubini, Gabriele, additional, Edelman, Elazer R., additional, Ehman, Richard L., additional, Finet, Gérard, additional, Fok, Pak-Wing, additional, Gasser, T. Christian, additional, Giddens, Don P., additional, Gijsen, Frank J.H., additional, Goerlich, Erin, additional, Gómez, Armida, additional, Goudot, Guillaume, additional, Guo, Xiaoya, additional, Hays, Allison G., additional, Hedin, Ulf, additional, Holzapfel, Gerhard A., additional, Jia, Haibo, additional, Jo, Hanjoong, additional, Kamm, Roger D., additional, Kassab, Ghassan S., additional, Kolipaka, Arunark, additional, Konofagou, Elisa E., additional, Lagache, Manuel, additional, Latorre, Álvaro T., additional, Le Floc'h, Simon, additional, Lehoux, Stephanie, additional, Ma, Genshan, additional, Maehara, Akiko, additional, Malvè, Mauro, additional, Martiel, Jean-Louis, additional, Martínez, Miguel A., additional, Matsumoto, Takeo, additional, Matsumura, Mitsuaki, additional, Migliavacca, Francesco, additional, Mintz, Gary S., additional, Mohammad Mirzaei, Navid, additional, Molony, David, additional, Nezami, Farhad Rikhtegar, additional, Ohayon, Jacques, additional, Oshinski, John N., additional, Peña, Estefanía, additional, Pernot, Mathieu, additional, Pettigrew, Roderic I., additional, Pomeroy, William L., additional, Rioufol, Gilles, additional, Roy, Joy, additional, Samady, Habib, additional, Shelton, Sarah E., additional, Stuber, Matthias, additional, Tacheau, Antoine, additional, Tamargo, Ian, additional, Tang, Dalin, additional, Timmins, Lucas H., additional, Turner, Emily A., additional, Wang, Liang, additional, Weinbaum, Sheldon, additional, Weiss, Robert G., additional, White, Richard D., additional, Yang, Chun, additional, Yazdani, Saami K., additional, Zheng, Jie, additional, and Zhu, Jian, additional

Published
2021
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9. Identification of Transversely Isotropic Properties from Magnetic Resonance Elastography Using the Optimised Virtual Fields Method

Author

Miller, Renee, Kolipaka, Arunark, Nash, Martyn P., Young, Alistair A., Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, Pop, Mihaela, editor, and Wright, Graham A, editor

Published
2017
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13. Determining Anisotropic Myocardial Stiffness from Magnetic Resonance Elastography: A Simulation Study

Author

Miller, Renee, Jiang, Haodan, Mazumder, Ria, Cowan, Brett R., Nash, Martyn P., Kolipaka, Arunark, Young, Alistair A., Hutchison, David, Series editor, Kanade, Takeo, Series editor, Kittler, Josef, Series editor, Kleinberg, Jon M., Series editor, Mattern, Friedemann, Series editor, Mitchell, John C., Series editor, Naor, Moni, Series editor, Pandu Rangan, C., Series editor, Steffen, Bernhard, Series editor, Terzopoulos, Demetri, Series editor, Tygar, Doug, Series editor, Weikum, Gerhard, Series editor, van Assen, Hans, editor, Bovendeerd, Peter, editor, and Delhaas, Tammo, editor

Published
2015
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14. Signal Generation

Author

Kolipaka, Arunark, Syed, Mushabbar A., editor, Raman, Subha V., editor, and Simonetti, Orlando P., editor

Published
2015
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26. Comparison of inversion methods inMRelastography: An open‐access pipeline for processing multifrequency shear‐wave data and demonstration in a phantom, human kidneys, and brain

Author

Meyer, Tom, primary, Marticorena Garcia, Stephan, additional, Tzschätzsch, Heiko, additional, Herthum, Helge, additional, Shahryari, Mehrgan, additional, Stencel, Lisa, additional, Braun, Jürgen, additional, Kalra, Prateek, additional, Kolipaka, Arunark, additional, and Sack, Ingolf, additional

Published
2022
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32. Validation of cardiac diffusion tensor imaging sequences: A multicentre test-retest phantom study

Author

Teh, Irvin, Romero R., William A., Boyle, Jordan, Coll-Font, Jaume, Dall'Armellina, Erica, Ennis, Daniel B., Ferreira, Pedro F., Kalra, Prateek, Kolipaka, Arunark, Kozerke, Sebastian, Lohr, David, Mongeon, François-Pierre, Moulin, Kévin, Nguyen, Christopher, Nielles-Vallespin, Sonia, Raterman, Brian, Schreiber, Laura M., Scott, Andrew D., Sosnovik, David E., and Stoeck, Christian

Subjects
multicentre, isotropic phantom, cardiac DTI, polyvinylpyrrolidone, pulse sequence validation, reproducibility
Abstract

Cardiac diffusion tensor imaging (DTI) is an emerging technique for the in vivo characterisation of myocardial microstructure, and there is a growing need for its validation and standardisation. We sought to establish the accuracy, precision, repeatability and reproducibility of state-of-the-art pulse sequences for cardiac DTI among 10 centres internationally. Phantoms comprising 0%–20% polyvinylpyrrolidone (PVP) were scanned with DTI using a product pulsed gradient spin echo (PGSE; N = 10 sites) sequence, and a custom motion-compensated spin echo (SE; N = 5) or stimulated echo acquisition mode (STEAM; N = 5) sequence suitable for cardiac DTI in vivo. A second identical scan was performed 1–9 days later, and the data were analysed centrally. The average mean diffusivities (MDs) in 0% PVP were (1.124, 1.130, 1.113) x 10(−3) mm2/s for PGSE, SE and STEAM, respectively, and accurate to within 1.5% of reference data from the literature. The coefficients of variation in MDs across sites were 2.6%, 3.1% and 2.1% for PGSE, SE and STEAM, respectively, and were similar to previous studies using only PGSE. Reproducibility in MD was excellent, with mean differences in PGSE, SE and STEAM of (0.3 ± 2.3, 0.24 ± 0.95, 0.52 ± 0.58) x 10(−5) mm2/s (mean ± 1.96 SD). We show that custom sequences for cardiac DTI provide accurate, precise, repeatable and reproducible measurements. Further work in anisotropic and/or deforming phantoms is warranted., NMR in Biomedicine, 35 (6), ISSN:0952-3480, ISSN:1099-1492

Published
2022
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39. Comparison of inversion methods in MR elastography: An open‐access pipeline for processing multifrequency shear‐wave data and demonstration in a phantom, human kidneys, and brain.

Author

Meyer, Tom, Marticorena Garcia, Stephan, Tzschätzsch, Heiko, Herthum, Helge, Shahryari, Mehrgan, Stencel, Lisa, Braun, Jürgen, Kalra, Prateek, Kolipaka, Arunark, and Sack, Ingolf

Subjects
KIDNEY cortex, ELASTOGRAPHY, KIDNEYS, MAGNETIC resonance, SHEAR waves
Abstract

Purpose: Magnetic resonance elastography (MRE) maps the viscoelastic properties of soft tissues for diagnostic purposes. However, different MRE inversion methods yield different results, which hinder comparison of values, standardization, and establishment of quantitative MRE markers. Here, we introduce an expandable, open‐access, webserver‐based platform that offers multiple inversion techniques for multifrequency, 3D MRE data. Methods: The platform comprises a data repository and standard MRE inversion methods including local frequency estimation (LFE), direct‐inversion based multifrequency dual elasto‐visco (MDEV) inversion, and wavenumber‐based (k‐) MDEV. The use of the platform is demonstrated in phantom data and in vivo multifrequency MRE data of the kidneys and brains of healthy volunteers. Results: Detailed maps of stiffness were generated by all inversion methods showing similar detail of anatomy. Specifically, the inner renal cortex had higher shear wave speed (SWS) than renal medulla and outer cortex without lateral differences. k‐MDEV yielded higher SWS values than MDEV or LFE (full kidney/brain k‐MDEV: 2.71 ± 0.19/1.45 ± 0.14 m/s, MDEV: 2.14 ± 0.16/0.99 ± 0.11 m/s, LFE: 2.12 ± 0.15/0.89 ± 0.06 m/s). Conclusion: The freely accessible platform supports the comparison of MRE results obtained with different inversion methods, filter thresholds, or excitation frequencies, promoting reproducibility in MRE across community‐developed methods. [ABSTRACT FROM AUTHOR]

Published
2022
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43. MR elastography: Principles, guidelines, and terminology

Author

Ralph, Sinkus, Manduca, Armando, Bayly, Philip, Ehman, Richard, Kolipaka, Arunark, Royston, Thomas, Sack, Ingolf, Sinkus, Ralph, Van Beers, Bernard, Mayo Clinic [Rochester], Washington University in Saint Louis (WUSTL), Ohio State University [Columbus] (OSU), University of Illinois [Chicago] (UIC), University of Illinois System, Charité - UniversitätsMedizin = Charité - University Hospital [Berlin], Laboratoire de Recherche Vasculaire Translationnelle (LVTS (UMR_S_1148 / U1148)), Université Paris Diderot - Paris 7 (UPD7)-Université Paris 13 (UP13)-Institut National de la Santé et de la Recherche Médicale (INSERM), Centre de recherche sur l'Inflammation (CRI (UMR_S_1149 / ERL_8252 / U1149)), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Université Paris 13 (UP13)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de la Santé et de la Recherche Médicale (INSERM), Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), and Ralph, Sinkus

Subjects
Liver Cirrhosis, medicine.medical_specialty, elastography, Computer science, [SDV.IB.IMA]Life Sciences [q-bio]/Bioengineering/Imaging, Phase contrast microscopy, Liver fibrosis, [SDV]Life Sciences [q-bio], mechanical properties, Palpation, Article, 030218 nuclear medicine & medical imaging, Terminology, law.invention, 03 medical and health sciences, 0302 clinical medicine, law, [SPI.MECA.BIOM] Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], medicine, Humans, Radiology, Nuclear Medicine and imaging, Medical physics, tissue stiffness, ComputingMilieux_MISCELLANEOUS, Confusion, MR elastography, medicine.diagnostic_test, [SPI.MECA.BIOM]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Biomechanics [physics.med-ph], Magnetic Resonance Imaging, 3. Good health, Processing methods, Magnetic resonance elastography, [SDV.IB.IMA] Life Sciences [q-bio]/Bioengineering/Imaging, Elasticity Imaging Techniques, Elastography, elasticity imaging, medicine.symptom, 030217 neurology & neurosurgery
Abstract

International audience; Magnetic resonance elastography (MRE) is a phase contrast-based MRI technique that can measure displacement due to propagating mechanical waves, from which material properties such as shear modulus can be calculated. Magnetic resonance elastography can be thought of as quantitative, noninvasive palpation. It is increasing in clinical importance, has become widespread in the diagnosis and staging of liver fibrosis, and additional clinical applications are being explored. However, publications have reported MRE results using many different parameters, acquisition techniques, processing methods, and varied nomenclature. The diversity of terminology can lead to confusion (particularly among clinicians) about the meaning of and interpretation of MRE results. This paper was written by the MRE Guidelines Committee, a group formalized at the first meeting of the ISMRM MRE Study Group, to clarify and move toward standardization of MRE nomenclature. The purpose of this paper is to (1) explain MRE terminology and concepts to those not familiar with them, (2) define "good practices" for practitioners of MRE, and (3) identify opportunities to standardize terminology, to avoid confusion.

Published
2021

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