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Designing long‐ T 2 suppression pulses for ultrashort echo time imaging
Author(s) -
Larson Peder E. Z.,
Gurney Paul T.,
Nayak Krishna,
Gold Garry E.,
Pauly John M.,
Nishimura Dwight G.
Publication year - 2006
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/mrm.20926
Subject(s) - magnetic resonance imaging , nuclear magnetic resonance , imaging phantom , echo time , sensitivity (control systems) , contrast (vision) , preclinical imaging , materials science , in vivo , physics , optics , medicine , radiology , biology , microbiology and biotechnology , electronic engineering , engineering
Ultrashort echo time (UTE) imaging has shown promise as a technique for imaging tissues with T 2 values of a few milliseconds or less. These tissues, such as tendons, menisci, and cortical bone, are normally invisible in conventional magnetic resonance imaging techniques but have signal in UTE imaging. They are difficult to visualize because they are often obscured by tissues with longer T 2 values. In this article, new long‐ T 2 suppression RF pulses that improve the contrast of short‐ T 2 species are introduced. These pulses are improvements over previous long‐ T 2 suppression pulses that suffered from poor off‐resonance characteristics or T 1 sensitivity. Short‐ T 2 tissue contrast can also be improved by suppressing fat in some applications. Dual‐band long‐ T 2 suppression pulses that additionally suppress fat are also introduced. Simulations, along with phantom and in vivo experiments using 2D and 3D UTE imaging, demonstrate the feasibility, improved contrast, and improved sensitivity of these new long‐ T 2 suppression pulses. The resulting images show predominantly short‐ T 2 species, while most long‐ T 2 species are suppressed. Magn Reson Med, 2006. © 2006 Wiley‐Liss, Inc.