title: Comparison of optimized soft-tissue suppression schemes for ultrashort echo time MRI.
abstract: Ultrashort echo time (UTE) imaging with soft-tissue suppression reveals short-T(2) components (typically hundreds of microseconds to milliseconds) ordinarily not captured or obscured by long-T(2) tissue signals on the order of tens of milliseconds or longer. Therefore, the technique enables visualization and quantification of short-T(2) proton signals such as those in highly collagenated connective tissues. This work compares the performance of the three most commonly used long-T(2) suppression UTE sequences, i.e., echo subtraction (dual-echo UTE), saturation via dual-band saturation pulses (dual-band UTE), and inversion by adiabatic inversion pulses (IR-UTE) at 3 T, via Bloch simulations and experimentally in vivo in the lower extremities of test subjects. For unbiased performance comparison, the acquisition parameters are optimized individually for each sequence to maximize short-T(2) signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR) between short- and long-T(2) components. Results show excellent short-T(2) contrast which is achieved with these optimized sequences. A combination of dual-band UTE with dual-echo UTE provides good short-T(2) SNR and CNR with less sensitivity to B(1) homogeneity. IR-UTE has the lowest short-T(2) SNR efficiency but provides highly uniform short-T(2) contrast and is well suited for imaging short-T(2) species with relatively short T(1) such as bone water.
authors.affiliation: Department of Radiology, University of Pennsylvania, Philadelphia, Pennsylvania, United States of America.
authors.forename: Cheng
authors.initials: C
authors.lastname: Li
authors.forename: Jeremy F
authors.initials: JF
authors.lastname: Magland
authors.forename: Hamidreza Saligheh
authors.initials: HS
authors.lastname: Rad
authors.forename: Hee Kwon
authors.initials: HK
authors.lastname: Song
authors.forename: Felix W
authors.initials: FW
authors.lastname: Wehrli
mesh_terms: D000125:Achilles Tendon / Q000033:anatomy & histology*; D000328:Adult; D000465:Algorithms; D003238:Connective Tissue / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013382:Subtraction Technique; D013977:Tibia / Q000033:anatomy & histology*; D055815:Young Adult