Three-dimensional ultrashort echo time cones T1ρ(3D UTE-cones-T1ρ) imaging.
We report a novel three-dimensional (3D) ultrashort echo time (UTE) sequence employing Cones trajectory and T1ρpreparation (UTE-Cones-T1ρ) for quantitative T1ρassessment of short T2tissues in the musculoskeletal system. A basic 3D UTE-Cones sequence was combined with a spin-locking preparation pulse for T1ρcontrast. A relatively short TR was used to decrease the scan time, which required T1measurement and compensation using 3D UTE-Cones data acquisitions with variable TRs. Another strategy to reduce the total scan time was to acquire multiple Cones spokes (Nsp) after each T1ρpreparation and fat saturation. Four spin-locking times (TSL = 0-20 ms) were acquired over 12 min, plus another 7 min for T1measurement. The 3D UTE-Cones-T1ρsequence was compared with a two-dimensional (2D) spiral-T1ρsequence for the imaging of a spherical CuSO4phantom and ex vivo meniscus and tendon specimens, as well as the knee and ankle joints of healthy volunteers, using a clinical 3-T scanner. The CuSO4phantom showed a T1ρvalue of 76.5 ± 1.6 ms with the 2D spiral-T1ρsequence, as well as 85.7 ± 3.6 and 89.2 ± 1.4 ms for the 3D UTE-Cones-T1ρsequences with Nspof 1 and 5, respectively. The 3D UTE-Cones-T1ρsequence provided shorter T1ρvalues for the bovine meniscus sample relative to the 2D spiral-T1ρsequence (10-12 ms versus 16 ms, respectively). The cadaveric human Achilles tendon sample could only be imaged with the 3D UTE-Cones-T1ρsequence (T1ρ= 4.0 ± 0.9 ms), with the 2D spiral-T1ρsequence demonstrating near-zero signal intensity. Human studies yielded T1ρvalues of 36.1 ± 2.9, 18.3 ± 3.9 and 3.1 ± 0.4 ms for articular cartilage, meniscus and the Achilles tendon, respectively. The 3D UTE-Cones-T1ρsequence allows volumetric T1ρmeasurement of short T2tissues in vivo.
Department of Radiology, University of California, San Diego, CA, USA.
Ya-Jun
YJ
Ma
GE Healthcare, San Diego, CA, USA.
Michael
M
Carl
Department of Radiology, University of California, San Diego, CA, USA.|Department of Radiology, Shanghai Tenth People's Hospital, Tongji University School of Medicine, Shanghai, China.
Hongda
H
Shao
Department of Radiology, University of California, San Diego, CA, USA.
Anthony S
AS
Tadros
Department of Radiology, University of California, San Diego, CA, USA.|Radiology Service, VA San Diego Healthcare System, San Diego, CA, USA.
Eric Y
EY
Chang
Department of Radiology, University of California, San Diego, CA, USA.
Jiang
http://orcid.org/0000-0002-9203-2450
J
Du
D000125:Achilles Tendon / Q000033:anatomy & histology; D000328:Adult; D000818:Animals; D002417:Cattle; D006801:Humans; D021621:Imaging, Three-Dimensional; D008297:Male; D019047:Phantoms, Imaging; D013997:Time Factors
Cones; T1; T1ρ; UTE; meniscus; short T2; tendon