Fast multistation water/fat imaging at 3T using DREAM‐based RF shimming. Issue 1 (21st October 2014)

• Record Type: Journal Article
• Authors: Hooijmans, Melissa T.; Dzyubachyk, Oleh; Nehrke, Kay; Koken, Peter; Versluis, Maarten J.; Kan, Hermien E.; Börnert, Peter
• Is Part Of: Journal of magnetic resonance imaging. Volume 42:Issue 1(2015)
• Page Start: 217
• Page End: 223
• Publication Date: 2014-10-21
• Subjects: Magnetic resonance imaging -- Periodicals; 616
• DOI: 10.1002/jmri.24775
• Languages: English
• ISSNs: 1053-1807

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="jmri24775-sec-0001" sec-type="section"> <title>Purpose</title> <p>To show the effect, efficiency, and image quality improvements achievable by Dual Refocusing Echo Acquisition Mode (DREAM)‐based <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjzsmbkv2" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:10531807:media:jmri24775:jmri24775-math-0001" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi mathvariant="normal">B</mml:mi><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives></inline-formula> shimming in whole‐body magnetic resonance imaging (MRI) at 3T using the example of water/fat imaging.</p> </sec> <sec id="jmri24775-sec-0002" sec-type="section"> <title>Materials and Methods</title> <p>3D multistation, dual‐echo mDixon gradient echo imaging was performed in 10 healthy subjects on a clinical 3T dual‐transmit MRI system using station‐to‐station adapted <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjzsmbktj" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:10531807:media:jmri24775:jmri24775-math-0002" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi mathvariant="normal">B</mml:mi><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives></inline-formula> shimming based on fast DREAM <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjzsmbks1" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:10531807:media:jmri24775:jmri24775-math-0003" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi mathvariant="normal">B</mml:mi><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives></inline-formula> mapping. Whole‐body data were obtained using conventional quadrature excitation and station‐by‐station adapted DREAM‐based <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjzsmbkpg" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:10531807:media:jmri24775:jmri24775-math-0004" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi mathvariant="normal">B</mml:mi><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives></inline-formula> shimmed excitation, along with the corresponding <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjzsmbm14" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:10531807:media:jmri24775:jmri24775-math-0005" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi mathvariant="normal">B</mml:mi><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives></inline-formula> maps for both excitation modes to assess image quality and radiofrequency (RF) performance.</p> </sec> <sec id="jmri24775-sec-0003" sec-type="section"> <title>Results</title> <p>Station‐dependent DREAM‐based <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjzsmbm0m" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:10531807:media:jmri24775:jmri24775-math-0006" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi mathvariant="normal">B</mml:mi><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives></inline-formula> shimming showed significantly improved image quality in the stations covering the upper legs, pelvis, and upper body region for all subjects (<italic>P</italic> < 0.02). This finding is supported by corresponding <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjzsmbkzm" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:10531807:media:jmri24775:jmri24775-math-0007" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi mathvariant="normal">B</mml:mi><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives></inline-formula> maps showing an improved <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjzsmbkx3" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:10531807:media:jmri24775:jmri24775-math-0008" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi mathvariant="normal">B</mml:mi><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives></inline-formula> homogeneity and a more precise flip angle in the DREAM‐based <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjzsmbmr0" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:10531807:media:jmri24775:jmri24775-math-0009" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi mathvariant="normal">B</mml:mi><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives></inline-formula> shimmed excitation (<italic>P</italic> < 0.01). Furthermore, the very short dual‐channel DREAM <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjzsmbmfb" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:10531807:media:jmri24775:jmri24775-math-0010" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi mathvariant="normal">B</mml:mi><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives></inline-formula> mapping times of less than 2 seconds facilitate quick <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjzsmbmdt" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:10531807:media:jmri24775:jmri24775-math-0011" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi mathvariant="normal">B</mml:mi><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives></inline-formula> shimming.</p> </sec> <sec id="jmri24775-sec-0004" sec-type="section"> <title>Conclusion</title> <p>Station‐dependent DREAM‐based <inline-formula><alternatives><inline-graphic mimetype="image" xlink:href="ark:/27927/pgjzsmbmhc" xlink:type="simple" xmlns:xlink="http://www.w3.org/1999/xlink" /><mml:math display="inline" altimg="urn:x-wiley:10531807:media:jmri24775:jmri24775-math-0012" overflow="scroll" xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msubsup><mml:mi mathvariant="normal">B</mml:mi><mml:mn>1</mml:mn><mml:mo>+</mml:mo></mml:msubsup></mml:mrow></mml:math></alternatives></inline-formula> shimming improved RF performance and image quality and is therefore a promising technique for whole‐body multistation imaging applications. <bold>J. Magn. Reson. Imaging 2015;42:217–223</bold>. © <bold>2014 Wiley Periodicals, Inc</bold>.</p> </sec> </abstract>