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«Item type text; Electronic Dissertation Authors Li, Zhiqiang Publisher The University of Arizona. Rights Copyright © is held by the author. Digital ...»

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Novel Body Magnetic Resonance Imaging Techniques

Item type text; Electronic Dissertation

Authors Li, Zhiqiang

Publisher The University of Arizona.

Rights Copyright © is held by the author. Digital access to this

material is made possible by the University Libraries,

University of Arizona. Further transmission, reproduction

or presentation (such as public display or performance) of

protected items is prohibited except with permission of the

author.

Downloaded 9-May-2016 23:37:48 Link to item http://hdl.handle.net/10150/193829

NOVEL BODY MAGNETIC RESONANCE IMAGING TECHNIQUES

by Zhiqiang Li A Dissertation Submitted to the Faculty of the

DEPARTMENT OF ELECTRICAL AND COMPUTER ENGINEERING

In Partial Fulfillment of the Requirements For the Degree of

DOCTOR OF PHILOSOPHY

In the Graduate College

THE UNIVERSITY OF ARIZONA

THE UNIVERSITY OF ARIZONA

GRADUATE COLLEGE

As members of the Dissertation Committee, we certify that we have read the dissertation prepared by Zhiqiang Li entitled Novel Body Magnetic Resonance Imaging Techniques and recommend that it be accepted as fulfilling the dissertation requirement for the Degree of Doctor of Philosophy Date: August 04, 2006 _______________________________________________________________________

Michael W. Marcellin, Ph.D.

Date: August 04, 2006 _______________________________________________________________________

Maria I. Altbach, Ph.D.

Date: August 04, 2006 _______________________________________________________________________

Arthur F. Gmitro, Ph.D.

Date: August 04, 2006 _______________________________________________________________________

Ali Bilgin, Ph.D.

Date: August 04, 2006 _______________________________________________________________________

Urs Utzinger, Ph.D.

Final approval and acceptance of this dissertation is contingent upon the candidate’s submission of the final copies of the dissertation to the Graduate College.

I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requirement.

________________________________________________ Date: August 04, 2006 Disser

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This dissertation has been submitted in partial fulfillment of requirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of the Library.

Brief quotations from this dissertation are allowable without special permission, provided that accurate acknowledgment of source is made. Requests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major department or the Dean of the Graduate College when in his or her judgment the proposed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author.

–  –  –

I am deeply indebted to my dissertation advisor, Dr. Maria I. Altbach.

Throughout my study at the University of Arizona, Dr. Altbach always acted as my advisor, teacher, and friend. Without her endless support and guidance, this dissertation would not have been possible.

I am also deeply grateful to Dr. Arthur F. Gmitro, my co-advisor. His insightful thoughts and valuable comments have helped me overcome numerous difficulties.

I would like to express my appreciation to my faculty advisor, Dr. Michael W.

Marcellin. He provided me numerous helps throughout my graduate study.

I would like to express my gratitude to Dr. Ali Bilgin. He offered help and insightful suggestions for my research. It was a pleasure to work with him. I also thank Dr. Theodore P. Trouard and Dr. Eric W. Clarkson for their thoughtful comments and Mr.

Scott W. Squire for helping with the imaging experiments.

More importantly, I wish to thank my parents, my wife, Li Guo, and my daughter, Katherine Yaxuan Li, for their endless love and support in all my educational endeavors.

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2.3 Experiments and results………………………………………………… 51 2.3.1 Phantom results…………………………………………………… 51 2.3.2 Ex vivo tissue results……………………………………………… 52 2.3.3 In vivo results……………………………………………………... 57

2.4 Limitations of the interleaved DIR-FSE method……………………….. 62

2.5 Parallel imaging with GRAPPA………………………………………... 63

CHAPTER 3 FAST DECOMPOSITION OF WATER AND LIPID USING A

GRADIENT AND SPIN-ECHO (GRASE) TECHNIQUE………………………. 70

3.1 Introduction ………………………….………..………………....……... 70

3.2 The initial IDEAL-GRASE implementation……..…………...………… 76 3.2.1 The pulse sequence…………………………………………………. 76 3.2.2 Preliminary phantom and in vivo results…………………………… 78





3.3 IDEAL-GRASE with phase error correction……..………...…………... 82

3.4 Theoretical noise performance evaluation of the IDEAL-GRASE technique…….………………………………………………………….. 84

3.5 Experiments and results………………………………………………… 89 3.5.1 Phase error correction in IDEAL-GRASE………………………….. 89 3.5.2 Noise performance in IDEAL-GRASE…………………………….. 94 3.5.3 In vivo applications…………………………………………………. 96

3.6 Discussion………………………….………………

CHAPTER 4 RAPID WATER AND LIPID IMAGING AND T2/T2†

MAPPING USING A RADIAL IDEAL-GRASE TECHNIQUE………………... 108

4.1 Introduction ……………………….……………………………………. 108 4.1.1 Motion artifacts…………………………………………………… 108 4.1.2 Radial MRI methods: Motion insensitivity……………………….. 111 4.1.3 Radial MRI methods: Parametric imaging………………………... 111

4.2 The radial IDEAL-GRASE technique………………………………….. 113

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Fig. 1.1 Cartesian imaging: (a) gradient waveform; (b) k-space trajectory…… 31 Fig. 1.2 Radial imaging: (a) gradient waveform; (b) k-space trajectory………. 32 Fig. 1.3 (a) Pulse sequence and (b) phase evolution for gradient echo………... 36 Fig. 1.4 Pulse sequence for spin-echo formation……………………………… 37 Fig. 1.5 Pulse sequence of fast spin-echo……………………………………... 38

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Fig. 2.2 Schematic representation of the conventional DIR-FSE method. (a) The pulse sequence (for simplicity, all gradient waveforms are not shown) and (b) the evolution of the longitudinal magnetization of tissue and blood flow…………………………………………………. 44 Fig. 2.3 Plot for signal intensity versus TR. The dotted and the broken curves are the transverse magnetization of lipid and water components (immediately after the 90° RF pulse of the FSE sequence), respectively. The solid curve is the difference between the two curves…………………………………………………………………. 47

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Fig. 2.5 Schematic representation of the DIR-FSE method for the interleaved acquisition of water- and lipid-suppressed data……………………… 50 Fig. 2.6 MR images of a water-lipid phantom (oil vials indicated by the arrows) acquired with (a) conventional FSE method where lipid and water are observed together and (b-d) with the interleaved lipid/water method. (b) Lipid and (c) water image obtained from interleaved lipid/water acquisition. (d) Combined lipid/water imaged obtained by adding images (b) and (c). Note that on (a) the oil vials are displaced

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Fig. 2.8 Images of ex vivo tissue obtained with DIR-FSE using clinicallyrelevant imaging parameters. (a) Image obtained with the conventional DIR-FSE method where lipid and water are observed together. (b) Lipid and (c) water image obtained with the interleaved DIR-FSE method. (d) Colorized lipid map overlaid onto the water image…

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Fig. 2.16 View ordering in conventional GRAPPA application, where the ACS lines are collected at the center of k-space…………………………… 67 Fig. 2.17 View ordering of FSE when combined with GRAPPA acquisition (a) standard and (b) distributed…………………………………………... 68 Fig. 2.18 Phantom image acquired with GRAPPA-FSE using (a) standard view ordering and (b) distributed view ordering…………………………… 69 Fig. 2.19 In vivo image of the heart acquired with GRAPPA-FSE using (a) standard view ordering and (b) distributed view ordering……………. 69 Fig. 3.1 Water image of the pelvis obtained with conventional chemical-shift saturation technique. Areas of failure of lipid suppression are pointed out by the arrows……………………………………………………… 71

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Fig. 3.3 Typical GRASE pulse sequence. For clarity, the slice selection gradient waveforms are not shown…………………………………… 76

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Fig. 3.5 (a) Water and (b) lipid images of the phantom obtained with the initial IDEAL-GRASE technique. (c) Water and (d) lipid images obtained with IDEAL-FSE technique………………………………… 79

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Fig. 3.7 Estimated phase error due to opposite polarities of the readout gradient with the FSE sequence. (a)The map of the phase error and (b) one line along the frequency encoding direction across the phase error map. The phase error in the background region outside the ball phantom is set to 0 using a mask……………………………………... 81 Fig. 3.8 Schematic diagram of IDEAL-GRASE with correction……………… 82 Fig. 3.9 Theoretical magnitude NSA (solid line) and Monte Carlo simulations

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Fig. 3.10 Relative SNR of (a) water and (b) lipid for various water:lipid ratios with echo shifts (from top to bottom in each plot) (-3π/2, -π/2, π/2, 3π/2), (-π/2, π/2, 3π/2), (-5π/6, -π/6, π/2, 7π/6), and (-π/6, π/2, 7π/6).

The plots are normalized such that the highest SNRrel is 1.………….. 89 Fig. 3.11 Phase error between data collected with opposite polarities of the readout gradients. (a-d) Phantom data acquired with a transmit/receive extremity coil. (e-f) Pelvic data acquired with a four channel phased-array coil (data shown is from one of the four receivers). The solid curve is the polynomial fit to the phase error (symbol). The background region outside the object is not shown in the figure. The axis, x, represents pixels in the image along the frequency encoding direction ………………………………………… 92 Fig. 3.12 (a-d) Decomposed water and lipid image of the phantom using IDEAL-GRASE from data acquired with a four channel phased-array coil. (a) Water and (b) lipid images obtained without phase error correction. (c) Water and (d) lipid images obtained with phase error correction. For comparison the (e) water and (f) lipid images generated using IDEAL-FSE are included. (g-j) Decomposed water and lipid image of the phantom using IDEAL-GRASE from data acquired with a transmit/receive extremity coil. (g) Water and (h) lipid images obtained without phase error correction. (i) Water and (j) lipid images obtained with phase error correction. The (k) water and (l) lipid images generated using IDEAL-FSE are also included........... 93

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Fig. 3.14 Lipid image of a water-lipid phantom obtained with IDEAL-GRASE with echo shifts (a) (-3π/2, -π/2, π/2, 3π/2) and (b) (-5π/6, -π/6, π/2, 7π/6). (c) Lipid image obtained using the conventional chemical-shift saturation technique…………………………………………………... 96 Fig. 3.15 Pelvic images obtained from IDEAL-GRASE. (a) Water and (b) lipid acquired at ±62.5 kHz. (c) Water and (d) lipid acquired at ±125 kHz,

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