Accelerated Quantitative 3D UTE-Cones Imaging Using Compressed Sensing

Abstract

In this study, the feasibility of accelerated quantitative Ultrashort Echo Time Cones (qUTE-Cones) imaging with compressed sensing (CS) reconstruction is investigated. qUTE-Cones sequences for variable flip angle-based UTE T1 mapping, UTE adiabatic T1ρ mapping, and UTE quantitative magnetization transfer modeling of macromolecular fraction (MMF) were implemented on a clinical 3T MR system. Twenty healthy volunteers were recruited and underwent whole-knee MRI using qUTE-Cones sequences. The k-space data were retrospectively undersampled with different undersampling rates. The undersampled qUTE-Cones data were reconstructed using both zero-filling and CS reconstruction. Using CS-reconstructed UTE images, various parameters were estimated in 10 different regions of interests (ROIs) in tendons, ligaments, menisci, and cartilage. Structural similarity, percentage error, and Pearson’s correlation were calculated to assess the performance. Dramatically reduced streaking artifacts and improved SSIM were observed in UTE images from CS reconstruction. A mean SSIM of ~0.90 was achieved for all CS-reconstructed images. Percentage errors between fully sampled and undersampled CS-reconstructed images were below 5% for up to 50% undersampling (i.e., 2× acceleration). High linear correlation was observed (>0.95) for all qUTE parameters estimated in all subjects. CS-based reconstruction combined with efficient Cones trajectory is expected to achieve a clinically feasible scan time for qUTE imaging.

Fast dual-echo estimation of apparent long T2 fraction using ultrashort echo time magnetic resonance imaging in tibialis tendons and its osteoporosis-related differences in women

“…For example, two-dimensional (2D) UTE acquisition ( 32 , 33 ) is faster than a three-dimensional (3D) acquisition (using radial, spiral, or cones trajectories) ( 22 , 34 ), while among the 3D acquisitions, the spiral or Cones is faster than a radial technique. Moreover, the UTE scan time can be improved by several acceleration techniques such as the stretching spokes in Cones ( 35 ), compressed sensing ( 36 - 38 ), and parallel imaging ( 39 , 40 ). Since the proposed method here for aFrac-LongT2 at most requires two acquisitions (for some resolutions it can be performed as one acquisition), they are likely faster than techniques with multiple acquisitions.…”

Whole knee joint mapping using a phase modulated UTE adiabatic T1ρ (PM‐UTE‐AdiabT1ρ) sequence

“…The scan time can be reduced with a smaller number of TSLs, longer spiral interleaves for data acquisition, and more spokes (i.e., a higher N sp value) in each TR 46,47 . Moreover, fast imaging techniques such as compressed sensing or deep learning can be incorporated to further accelerate data acquisition 48–51 . Fourth, the image SNR increases when a longer T rec is used, leading to a longer total scan time.…”

“…46,47 Moreover, fast imaging techniques such as compressed sensing or deep learning can be incorporated to further accelerate data acquisition. [48][49][50][51] Fourth, the image SNR increases when a longer T rec is used, leading to a longer total scan time. Longer T rec s will be investigated when fast imaging techniques are available to accelerate the PM-UTE-AdiabT 1ρ scan.…”

MRI-based porosity index (PI) and suppression ratio (SR) in the tibial cortex show significant differences between normal, osteopenic, and osteoporotic female subjects

“…It should be noted that the required scan time for all UTE MRI techniques can be improved by different acceleration techniques such as spokes stretching in Cones ( 27 ), compressed sensing ( 28 , 29 ), and parallel imaging ( 30 , 31 ). Since both PI and SR measurements require only two acquisitions, they may be faster than other techniques which require multiple acquisitions ( 19 , 32 – 42 ), if similar acceleration techniques are utilized.…”