Volumetric Perfusion MRI of Liver Tumors to Detect Early Response to Chemotherapy

Summary

Principal Investigator: Scott B Reeder
Abstract: DESCRIPTION (provided by applicant): In the last several years, there has been a remarkable transformation in the field of cancer therapeutics, with a shift from traditional "cytotoxic" agents to targeted therapies. There has also been a rapid increase in the number of potential compounds available for investigation. This trend has necessitated the development of innovative biomarkers that rapidly assess tumor response of a patient's tumor to a specific agent. Such biomarkers are urgently needed to personalize the treatment of tumors with effective agents. The overall purpose of this work is to develop new imaging strategies that measure early response to anti-angiogenic chemotherapeutic agents in liver tumors, using new magnetic resonance imaging (MRI) methods that measure blood flow to tumors (perfusion). Currently, the assessment of tumor response relies on the measurement of tumor size based on standard size criteria guidelines. This process requires months of treatment that may be ineffective or toxic and is often very expensive. Moreover, new "anti- angiogenic" agents that interfere with the blood flow to growing tumors may provide clinical benefit while not actually resulting in a decrease in tumor size. For example, treatment with sorafenib (a new anti-angiogenic drug) results in a 3-month improvement in overall survival in advanced primary liver tumors (hepatocellular carcinoma (HCC)), while only 3% of tumors actually decreased in size. However, anti-angiogenic agents, such as sorafenib have a dramatic impact on the microscopic blood vessels of tumors within just hours or a few days. This underscores the concept that tumor size, measured with current cross-sectional imaging methods (CT or MRI), is a late indicator of tumor response, and does not reflect early changes from treatment at the cellular level. Therefore, we hypothesize that early changes of tumor blood flow are predictive of long-term tumor regression or stabilization in patients treated with anti-angiogenic chemotherapy. Our proposed studies could lead to more efficient evaluation of treatment options for tumors such as hepatocellular carcinoma (HCC) and metastatic liver tumors and may provide new measurements of tumor response in an effort to deliver more individualized cancer care in the future. This application addresses the broad Challenge Area (05): "Comparative Effectiveness Research" and specific Challenge Topic, 05-EB-101 Comparative Effectiveness of Advanced Imaging Procedures. As described below, we propose to evaluate the clinical and cost effectiveness of advanced perfusion MRI methods to characterize blood flow to liver tumors before and immediately after initiation of systemic therapy. We aim to determine the comparative effectiveness of advanced perfusion MRI with conventional cross- sectional imaging methods (CT) that measure tumor response based size, using tumor size criteria. By identifying tumors that will not respond to these drugs, their toxic side effects are avoided, and tremendous cost savings can be realized (eg. sorafenib costs ~$4000/month). Dynamic contrast enhanced perfusion imaging with MRI after the bolus injection of Gadolinium based contrast agents, is a safe, accurate and well-established method for characterizing blood flow (perfusion) in malignant tumors in various organs including the brain, breast, and prostate, among others. Unfortunately, perfusion imaging in the liver, the largest organ in the body, is challenging, and to date no methods have adequately provided the necessary combination of: 1) volumetric coverage, 2) high spatial resolution and 3) high temporal resolution, while maintaining 4) good signal to noise ratio (SNR), and 5) fidelity of Gadolinium contrast uptake curves in tissue. In this proposal we will use a novel perfusion MRI method based on a time resolved 3D "radial" sampling methods developed at UW-Madison. Using a state of the art high-field (3.0T) clinical MRI scanner, we will combine this approach with a "constrained reconstruction" algorithm to maximize the SNR performance and temporal resolution. Using the combination of 3D radial imaging and constrained reconstruction, we will acquire a time series of volumetric 3D images every 3 seconds, with very high spatial resolution (2.0x2.0x2.0mm3). Compared to the current state of the art, our approach increases temporal resolution by a factor of two and increases spatial resolution by a factor of five. To achieve these goals, we will 1) implement and test the new method on a state of the art 3.0T clinical scanner in volunteers, and in patients with hepatocellular carcinoma, and 2) Determine the impact of the optimized method on clinical outcome through a prospective longitudinal pilot study in HCC patients undergoing anti-angiogenic therapy. Successful validation of the proposed MRI measures of tumor response will provide a new image-based approach for clinical decision-making for chemotherapeutic regimens by transforming how MRI is used as a measure of tumor response. Treating physicians will be able to rapidly determine which chemotherapeutic agents are effective, while avoiding ineffective agents and their toxicities. Such methods would enable "personalized" chemotherapy, rapidly determining the most effective agents for an individual's tumor(s). PUBLIC HEALTH RELEVANCE: This proposal describes a new, non-invasive method that uses magnetic resonance imaging (MRI) to measure blood flow in liver tumors, in order to determine whether drugs used to treat these tumors are effective. Currently, patients must undergo 2-3 months of treatment in order to see if the drug is effective against the tumor. Using the new perfusion MRI methods, the effectiveness of the drug will be ascertained in 2 days, and the prolonged use of ineffective, toxic and expensive drugs can be avoided and alternative therapies pursued.
Funding Period: ----------------2009 - ---------------2011-
more information: NIH RePORT

Top Publications

  1. ncbi Optimal timing and diagnostic adequacy of hepatocyte phase imaging with gadoxetate-enhanced liver MRI
    Mustafa R Bashir
    Department of Radiology, Duke University Medical Center, DUMC 3808, Durham, NC 27710 Electronic address
    Acad Radiol 21:726-32. 2014
  2. pmc Fat confounds the observed apparent diffusion coefficient in patients with hepatic steatosis
    Jan Hansmann
    Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
    Magn Reson Med 69:545-52. 2013
  3. pmc In vivo validation of 4D flow MRI for assessing the hemodynamics of portal hypertension
    Alejandro Roldan-Alzate
    Department of Radiology, University of Wisconsin, Madison, WI 53705, USA
    J Magn Reson Imaging 37:1100-8. 2013
  4. pmc R2* estimation using "in-phase" echoes in the presence of fat: the effects of complex spectrum of fat
    Diego Hernando
    Department of Radiology, University of Wisconsin, Madison, Wisconsin 53705, USA
    J Magn Reson Imaging 37:717-26. 2013
  5. pmc Adipose tissue MRI for quantitative measurement of central obesity
    Aziz H Poonawalla
    Department of Radiology, University of Wisconsin, Madison, Wisconsin 53792 3252, USA
    J Magn Reson Imaging 37:707-16. 2013
  6. pmc Quantification of hepatic steatosis with dual-energy computed tomography: comparison with tissue reference standards and quantitative magnetic resonance imaging in the ob/ob mouse
    Nathan S Artz
    Department of Radiology, University of Wisconsin, Madison, WI 53705 2275, USA
    Invest Radiol 47:603-10. 2012
  7. pmc Characterization of hepatic adenoma and focal nodular hyperplasia with gadoxetic acid
    Kiyarash Mohajer
    Department of Radiology, University of Wisconsin, 600 Highland Ave, Madison, WI 53792, USA
    J Magn Reson Imaging 36:686-96. 2012
  8. pmc High resolution navigated three-dimensional T₁-weighted hepatobiliary MRI using gadoxetic acid optimized for 1.5 Tesla
    Scott K Nagle
    Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
    J Magn Reson Imaging 36:890-9. 2012
  9. pmc R*(2) mapping in the presence of macroscopic B₀ field variations
    Diego Hernando
    Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
    Magn Reson Med 68:830-40. 2012
  10. pmc Optimized high-resolution contrast-enhanced hepatobiliary imaging at 3 tesla: a cross-over comparison of gadobenate dimeglumine and gadoxetic acid
    Alex Frydrychowicz
    Department of Radiology, University of Wisconsin Madison, Wisconsin 73727, USA
    J Magn Reson Imaging 34:585-94. 2011

Scientific Experts

  • Scott B Reeder
  • Kang Wang
  • Bachir Taouli
  • Christopher J Francois
  • Kevin M Johnson
  • Mark Bydder
  • Ethan K Brodsky
  • D Hernando
  • Ananth J Madhuranthakam
  • Huanzhou Yu
  • Catherine D G Hines
  • Alex Frydrychowicz
  • Jean H Brittain
  • Ann Shimakawa
  • Scott K Nagle
  • Charles A McKenzie
  • Eric M Bultman
  • Richard Kijowski
  • Venkata V Chebrolu
  • Debra E Horng
  • Alejandro Roldan-Alzate
  • Walter F Block
  • Thorsten A Bley
  • Peter M Wolfgram
  • Philip J Beatty
  • Mustafa R Bashir
  • Jennifer L Rehm
  • Pablo Irarrazaval
  • Jan Hansmann
  • Aziz H Poonawalla
  • Nathan S Artz
  • Kiyarash Mohajer
  • Oliver Wieben
  • A Frydrychowicz
  • Karl K Vigen
  • Brian J Soher
  • Angel R Pineda
  • Christina A Chen
  • Wenmiao Lu
  • James H Holmes
  • Rendon C Nelson
  • William R Schelman
  • David B Allen
  • Jessica Klaers
  • Richard K Do
  • Ellen L Connor
  • Steven R Breault
  • Anja C S Brau
  • Ryan Braun
  • Jens C Eickhoff
  • Mark L Schiebler
  • Shaorong Chang
  • Eric Niespodzany
  • Ben R Landgraf
  • Brett P Sjoberg
  • Catherine D Hines
  • Jessica B Robbins
  • Calista Roen
  • Neil M Rofsky
  • Eric Bultman
  • Jeffrey J Brown
  • Stephen T Brunner
  • Rashmi M Agni
  • Reed F Busse
  • Rashmi Agni
  • Anja C Brau
  • Meghan G Lubner
  • Agnes G Loeffler
  • Guang Hong Chen
  • Frederick Kelcz
  • Elmar M Merkle
  • Ian Rowland
  • Yuji Iwadate
  • Jens Peter Kuhn
  • Debra Horng
  • Thomas D Reed
  • Andrzej R Jedynak
  • Dana L Tudorascu
  • B R Landgraf
  • E Niespodzany
  • Gavin Hamilton
  • A Roldan-Alzate
  • Claude B Sirlin
  • R W Verma
  • O Wieben
  • Sharon L D'Souza
  • Jessica L Klaers
  • James R MacFall
  • Mary J Lindstrom
  • Kirkland W Davis

Detail Information

Publications52

  1. ncbi Optimal timing and diagnostic adequacy of hepatocyte phase imaging with gadoxetate-enhanced liver MRI
    Mustafa R Bashir
    Department of Radiology, Duke University Medical Center, DUMC 3808, Durham, NC 27710 Electronic address
    Acad Radiol 21:726-32. 2014
    ..To evaluate clinical and imaging features associated with adequacy of the hepatocyte phase (HP) in gadoxetate disodium-enhanced liver magnetic resonance imaging (MRI) in patients without chronic liver disease (CLD)...
  2. pmc Fat confounds the observed apparent diffusion coefficient in patients with hepatic steatosis
    Jan Hansmann
    Department of Clinical Radiology and Nuclear Medicine, University Medical Center Mannheim, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
    Magn Reson Med 69:545-52. 2013
    ..In this work, we investigated the dependence of the apparent diffusion coefficient (ADC) on liver fat content and whether it is confounded by fat signal...
  3. pmc In vivo validation of 4D flow MRI for assessing the hemodynamics of portal hypertension
    Alejandro Roldan-Alzate
    Department of Radiology, University of Wisconsin, Madison, WI 53705, USA
    J Magn Reson Imaging 37:1100-8. 2013
    ..To implement and validate in vivo radial 4D flow MRI for quantification of blood flow in the hepatic arterial, portal venous, and splanchnic vasculature of healthy volunteers and patients with portal hypertension...
  4. pmc R2* estimation using "in-phase" echoes in the presence of fat: the effects of complex spectrum of fat
    Diego Hernando
    Department of Radiology, University of Wisconsin, Madison, Wisconsin 53705, USA
    J Magn Reson Imaging 37:717-26. 2013
    ..To investigate R2* mapping robustness in the presence of fat using in-phase echoes, without and with spectral modeling of fat (single-peak and multipeak models, respectively), using varying numbers of echoes...
  5. pmc Adipose tissue MRI for quantitative measurement of central obesity
    Aziz H Poonawalla
    Department of Radiology, University of Wisconsin, Madison, Wisconsin 53792 3252, USA
    J Magn Reson Imaging 37:707-16. 2013
    ..To validate adipose tissue magnetic resonance imaging (atMRI) for rapid, quantitative volumetry of visceral adipose tissue (VAT) and total adipose tissue (TAT)...
  6. pmc Quantification of hepatic steatosis with dual-energy computed tomography: comparison with tissue reference standards and quantitative magnetic resonance imaging in the ob/ob mouse
    Nathan S Artz
    Department of Radiology, University of Wisconsin, Madison, WI 53705 2275, USA
    Invest Radiol 47:603-10. 2012
    ....
  7. pmc Characterization of hepatic adenoma and focal nodular hyperplasia with gadoxetic acid
    Kiyarash Mohajer
    Department of Radiology, University of Wisconsin, 600 Highland Ave, Madison, WI 53792, USA
    J Magn Reson Imaging 36:686-96. 2012
    ..To characterize imaging features of histologically proven hepatic adenoma (HA) as well as histologically and/or radiologically proven focal nodular hyperplasia (FNH) using delayed hepatobiliary MR imaging with 0.05 mmol/kg gadoxetic acid...
  8. pmc High resolution navigated three-dimensional T₁-weighted hepatobiliary MRI using gadoxetic acid optimized for 1.5 Tesla
    Scott K Nagle
    Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
    J Magn Reson Imaging 36:890-9. 2012
    ..5 Tesla (T) with gadoxetic acid and to demonstrate the feasibility of using a high-resolution navigated optimized T1-weighted pulse sequence to evaluate biliary disease...
  9. pmc R*(2) mapping in the presence of macroscopic B₀ field variations
    Diego Hernando
    Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
    Magn Reson Med 68:830-40. 2012
    ..The proposed method is tested on several 2D and 3D phantom and in vivo liver, cardiac, and brain datasets...
  10. pmc Optimized high-resolution contrast-enhanced hepatobiliary imaging at 3 tesla: a cross-over comparison of gadobenate dimeglumine and gadoxetic acid
    Alex Frydrychowicz
    Department of Radiology, University of Wisconsin Madison, Wisconsin 73727, USA
    J Magn Reson Imaging 34:585-94. 2011
    ..1 mmol/kg gadobenate dimeglumine for dynamic and hepatobiliary phase imaging. In addition, flip angles (FA) that maximize relative contrast-to-noise performance for hepatobiliary phase imaging were determined...
  11. pmc Comparison of R2* correction methods for accurate fat quantification in fatty liver
    Debra E Horng
    Department of Radiology, University of Wisconsin, Madison, Wisconsin 53792 3252, USA
    J Magn Reson Imaging 37:414-22. 2013
    ..To compare the performance of fat fraction quantification using single-R(2)* and dual-R(2)* correction methods in patients with fatty liver, using MR spectroscopy (MRS) as the reference standard...
  12. pmc Multipeak fat-corrected complex R2* relaxometry: theory, optimization, and clinical validation
    Diego Hernando
    Departments of Radiology, University of Wisconsin, Madison, Wisconsin, USA
    Magn Reson Med 70:1319-31. 2013
    ..To develop R2* mapping techniques corrected for confounding factors and optimized for noise performance...
  13. pmc Quantitative hepatic perfusion modeling using DCE-MRI with sequential breathholds
    Eric M Bultman
    Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin, USA
    J Magn Reson Imaging 39:853-65. 2014
    ..To develop and demonstrate the feasibility of a new formulation for quantitative perfusion modeling in the liver using interrupted DCE-MRI data acquired during multiple sequential breathholds...
  14. pmc Non-contrast enhanced 3D SSFP MRA of the renal allograft vasculature: a comparison between radial linear combination and Cartesian inflow-weighted acquisitions
    Eric M Bultman
    Department of Biomedical Engineering, University of Wisconsin, Madison, WI Electronic address
    Magn Reson Imaging 32:190-5. 2014
    ..005). These two methods of non-contrast MR imaging each have significant strengths and are complementary to each other in evaluating the vasculature of renal allografts. ..
  15. pmc Design of k-space channel combination kernels and integration with parallel imaging
    Philip J Beatty
    Global Applied Science Laboratory, GE Healthcare, Toronto, Canada Physical Sciences, Sunnybrook Research Institute, Toronto, Canada Department of Medical Biophysics, University of Toronto, Toronto, Canada
    Magn Reson Med 71:2139-54. 2014
    ..Additionally, this work describes how these channel combination kernels can be combined with local k-space unaliasing kernels produced by the calibration phase of parallel imaging methods such as GRAPPA, PARS and ARC...
  16. pmc Ethnic differences in the effects of hepatic fat deposition on insulin resistance in nonobese middle school girls
    Peter M Wolfgram
    Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin, USA
    Obesity (Silver Spring) 22:243-8. 2014
    ..In nonobese youth, to investigate whether hepatic fat deposition and its metabolic consequences vary between ethnic groups...
  17. pmc Four-dimensional velocity mapping of the hepatic and splanchnic vasculature with radial sampling at 3 tesla: a feasibility study in portal hypertension
    A Frydrychowicz
    Department of Radiology, University of Wisconsin Madison, Wisconsin 53729, USA
    J Magn Reson Imaging 34:577-84. 2011
    ..To demonstrate the feasibility of PC-VIPR (Phase Contrast Vastly undersampled Imaging with Projection Reconstruction) for the depiction and hemodynamic analysis of hepatic and splanchnic vessels in patients with portal hypertension...
  18. ncbi Generalized k-space decomposition with chemical shift correction for non-Cartesian water-fat imaging
    Ethan K Brodsky
    Department of Radiology, University of Wisconsin Madison, 600 Highland Avenue, Madison, WI 53792, USA
    Magn Reson Med 59:1151-64. 2008
    ..The improved multipeak decomposition is demonstrated with water-fat imaging, showing a substantial improvement in water-fat separation...
  19. pmc T1 independent, T2* corrected MRI with accurate spectral modeling for quantification of fat: validation in a fat-water-SPIO phantom
    Catherine D G Hines
    Department of Radiology, University of Wisconsin, Madison, Wisconsin 53792 3252, USA
    J Magn Reson Imaging 30:1215-22. 2009
    ....
  20. pmc Noninvasive temperature mapping with MRI using chemical shift water-fat separation
    Brian J Soher
    Department of Radiology, Duke University, Durham, North Carolina 27710, USA
    Magn Reson Med 63:1238-46. 2010
    ..Region of interest (ROI) temperature values colocated with the probes showed excellent agreement (global mean +/- standard deviation: -0.09 +/- 0.34 degrees C) despite significant amplitude of static field drift during the experiments...
  21. pmc Quantification of hepatic steatosis with MRI: the effects of accurate fat spectral modeling
    Scott B Reeder
    Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
    J Magn Reson Imaging 29:1332-9. 2009
    ..Quantitative noninvasive biomarkers of hepatic steatosis are urgently needed for the diagnosis and management of nonalcoholic fatty liver disease (NAFLD)...
  22. pmc Improved fat suppression using multipeak reconstruction for IDEAL chemical shift fat-water separation: application with fast spin echo imaging
    Richard Kijowski
    Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
    J Magn Reson Imaging 29:436-42. 2009
    ..To evaluate and quantify improvements in the quality of fat suppression for fast spin-echo imaging of the knee using multipeak fat spectral modeling and IDEAL fat-water separation...
  23. pmc Gadoxetic acid-enhanced T1-weighted MR cholangiography in primary sclerosing cholangitis
    Alex Frydrychowicz
    Clinic for Radiology and Nucelar Medicine, University Hospital Schleswig Holstein, Campus Lubeck, Lubeck, Germany
    J Magn Reson Imaging 36:632-40. 2012
    ....
  24. pmc Multiecho water-fat separation and simultaneous R2* estimation with multifrequency fat spectrum modeling
    Huanzhou Yu
    Global MR Applied Science Lab, GE Healthcare, Menlo Park, California, USA
    Magn Reson Med 60:1122-34. 2008
    ..The improvement in water-fat separation and T(2) (*) estimation is demonstrated in a variety of in vivo applications, including knee, ankle, spine, breast, and abdominal scans...
  25. ncbi Water-fat separation with bipolar multiecho sequences
    Wenmiao Lu
    Department of Radiology, Stanford University, Stanford, CA 94305, USA
    Magn Reson Med 60:198-209. 2008
    ..The proposed methods are validated both in phantoms and in vivo to enable reliable and SNR efficient water-fat separation with bipolar multiecho sequences...
  26. pmc Cartilage imaging at 3.0T with gradient refocused acquisition in the steady-state (GRASS) and IDEAL fat-water separation
    Richard Kijowski
    Department of Radiology, University of Wisconsin, 600 Highland Avenue, Madison, WI 53792, USA
    J Magn Reson Imaging 28:167-74. 2008
    ..0T using gradient refocused acquisition in the steady-state (GRASS) and iterative decomposition of water and fat with echo asymmetry and least-squares estimation (IDEAL) fat-water separation...
  27. pmc Cartilage morphology at 3.0T: assessment of three-dimensional magnetic resonance imaging techniques
    Christina A Chen
    Department of Radiology, Stanford University, Stanford, California, USA
    J Magn Reson Imaging 32:173-83. 2010
    ..To compare six new three-dimensional (3D) magnetic resonance (MR) methods for evaluating knee cartilage at 3.0T...
  28. ncbi Cardiac MRI evaluation of nonischemic cardiomyopathies
    Christopher J Francois
    Department of Radiology, University of Wisconsin, Madison, Wisconsin 53792 3252, USA
    J Magn Reson Imaging 31:518-30; quiz 517. 2010
    ..Findings on cardiac MRI studies can help distinguish between different types of cardiomyopathies and can provide valuable diagnostic and prognostic information...
  29. pmc Quantification of hepatic steatosis with 3-T MR imaging: validation in ob/ob mice
    Catherine D G Hines
    Department of Biomedical Engineering, University of Wisconsin, 600 Highland Ave, E3 311 CSC, Madison, WI 53792 3252, USA
    Radiology 254:119-28. 2010
    ..To validate quantitative imaging techniques used to detect and measure steatosis with magnetic resonance (MR) imaging in an ob/ob mouse model of hepatic steatosis...
  30. ncbi Fat and water magnetic resonance imaging
    Thorsten A Bley
    Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
    J Magn Reson Imaging 31:4-18. 2010
    ..This enables the reader to understand the reasons why some fat suppression methods work better than others in specific clinical settings...
  31. pmc Advanced MRI methods for assessment of chronic liver disease
    Bachir Taouli
    Department of Radiology, MRI, New York University Medical Center, 530 First Ave, New York, NY 10016, USA
    AJR Am J Roentgenol 193:14-27. 2009
    ..We will review the respective roles of these techniques for assessment of chronic liver disease...
  32. pmc Repeatability of magnetic resonance elastography for quantification of hepatic stiffness
    Catherine D G Hines
    Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin 53792 3252, USA
    J Magn Reson Imaging 31:725-31. 2010
    ....
  33. pmc Independent estimation of T*2 for water and fat for improved accuracy of fat quantification
    Venkata V Chebrolu
    Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin, USA
    Magn Reson Med 63:849-57. 2010
    ..The tradeoffs in algorithm stability and accuracy between multiexponential and single exponential techniques are discussed...
  34. pmc k-space water-fat decomposition with T2* estimation and multifrequency fat spectrum modeling for ultrashort echo time imaging
    Kang Wang
    Department of Medical Physics, University of Wisconsin, Madison, Wisconsin 53705 2275, USA
    J Magn Reson Imaging 31:1027-34. 2010
    ..To demonstrate the feasibility of combining a chemical shift-based water-fat separation method (IDEAL) with a 2D ultrashort echo time (UTE) sequence for imaging and quantification of the short T(2) tissues with robust fat suppression...
  35. pmc On the performance of T2* correction methods for quantification of hepatic fat content
    Scott B Reeder
    Department of Radiology, University of Wisconsin, Madison, Wisconsin 53792 3252, USA
    Magn Reson Med 67:389-404. 2012
    ..Interestingly, when an echo spacing and first echo shift of ∼π/2 are used, methods without T(2)* correction have less than 5% bias in the estimates of fat fraction...
  36. pmc Addressing phase errors in fat-water imaging using a mixed magnitude/complex fitting method
    D Hernando
    Department of Radiology, University of Wisconsin, Madison, Wisconsin 53705, USA
    Magn Reson Med 67:638-44. 2012
    ..We demonstrate that mixed fitting is able to provide accurate fat fraction measurements with high signal-to-noise ratio and low bias over a wide choice of echo combinations...
  37. pmc Constraining the initial phase in water-fat separation
    Mark Bydder
    Department of Radiology, University of California San Diego, San Diego, CA, USA
    Magn Reson Imaging 29:216-21. 2011
    ..The advantages of phase constrained water-fat separation, namely, improved noise performance and/or reduced data requirements (fewer echos), are demonstrated in simulations and experiments...
  38. ncbi Quantitative assessment of liver fat with magnetic resonance imaging and spectroscopy
    Scott B Reeder
    Liver Imaging Research Program, Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
    J Magn Reson Imaging 34:729-49. 2011
    ..These advanced techniques show promise for accurate fat quantification and are likely to be commercially available soon...
  39. pmc Validation of MRI biomarkers of hepatic steatosis in the presence of iron overload in the ob/ob mouse
    Catherine D G Hines
    Department of Radiology, University of Wisconsin, Madison, Wisconsin, USA
    J Magn Reson Imaging 35:844-51. 2012
    ..To validate the utility and performance of a T 2 correction method for hepatic fat quantification in an animal model of both steatosis and iron overload...
  40. pmc Improved least squares MR image reconstruction using estimates of k-space data consistency
    Kevin M Johnson
    Department of Medical Physics, University of Wisconsin, Madison, Wisconsin 53705, USA
    Magn Reson Med 67:1600-8. 2012
    ..The data consistency weighting technique substantially improved image quality and reduced noise as compared to traditional reconstruction approaches...
  41. pmc T(2)-weighted 3D fast spin echo imaging with water-fat separation in a single acquisition
    Ananth J Madhuranthakam
    Applied Science Lab, GE Healthcare, Boston, Massachusetts, USA
    J Magn Reson Imaging 32:745-51. 2010
    ..To develop a robust 3D fast spin echo (FSE) T(2)-weighted imaging method with uniform water and fat separation in a single acquisition, amenable to high-quality multiplanar reformations...
  42. pmc Hepatobiliary MR imaging with gadolinium-based contrast agents
    Alex Frydrychowicz
    Department of Radiology and Nuclear Medicine, University of Hospital Schleswig Holstein, Campus Lubeck, Lubeck, Germany
    J Magn Reson Imaging 35:492-511. 2012
    ..It is our aim that the information provided in this article will facilitate the optimal utilization of these agents and will stimulate the reader's pursuit of new applications for future benefit...
  43. pmc Frequency response of multipoint chemical shift-based spectral decomposition
    Ethan K Brodsky
    Department of Radiology, University of Wisconsin, Madison, Wisconsin 53705 2275, USA
    J Magn Reson Imaging 32:943-52. 2010
    ..To provide a framework for characterizing the frequency response of multipoint chemical shift based species separation techniques...
  44. pmc Noise analysis for 3-point chemical shift-based water-fat separation with spectral modeling of fat
    Venkata V Chebrolu
    Department of Biomedical Engineering, University of Wisconsin, Madison, Wisconsin 53792 3252, USA
    J Magn Reson Imaging 32:493-500. 2010
    ..The echo combination that achieves the best SNR performance for a given spectral model of fat was also investigated...
  45. pmc Phase and amplitude correction for multi-echo water-fat separation with bipolar acquisitions
    Huanzhou Yu
    Applied Science Laboratory, GE Healthcare, Menlo Park, California, USA
    J Magn Reson Imaging 31:1264-71. 2010
    ..To address phase and amplitude errors for multi-point water-fat separation with "bipolar" acquisitions, which efficiently collect all echoes with alternating read-out gradient polarities in one repetition...
  46. pmc T(1) independent, T(2) (*) corrected chemical shift based fat-water separation with multi-peak fat spectral modeling is an accurate and precise measure of hepatic steatosis
    Catherine D G Hines
    Department of Radiology, University of Wisconsin, Madison, WI, USA
    J Magn Reson Imaging 33:873-81. 2011
    ..To determine the precision and accuracy of hepatic fat-fraction measured with a chemical shift-based MRI fat-water separation method, using single-voxel MR spectroscopy (MRS) as a reference standard...