Faculty Collaboration Database

3D-T_1ρ prepared zero echo time-based PETRA sequence for in vivo biexponential relaxation mapping of semisolid short-T₂ tissues at 3 T. J Magn Reson Imaging 2019 Oct;50(4):1207-1218

Date

01/30/2019

Pubmed ID

30693600

Pubmed Central ID

PMC6816051

DOI

10.1002/jmri.26664

Scopus ID

2-s2.0-85060767532 (requires institutional sign-in at Scopus site)   8 Citations

Abstract

BACKGROUND: In addition to the articular cartilage, osteoarthritis (OA) affects several other tissues such as tendons, ligaments, and subchondral bone. T1_ρ relaxation study of these short T₂ tissues may provide a more comprehensive evaluation of OA.

PURPOSE: To develop a 3D spin-lattice relaxation in the rotating frame (T_1ρ ) prepared zero echo time (ZTE)-based pointwise encoding time reduction with radial acquisition (3D-T_1ρ -PETRA) sequence for relaxation mapping of semisolid short-T₂ tissues on a clinical 3 T scanner.

STUDY TYPE: Prospective.

POPULATION: Phantom, two bovine whole knee joint and Achilles tendon specimens, 10 healthy volunteers with no known inflammation, trauma or pain in the knee or ankle.

FIELD STRENGTH/SEQUENCE: A customized PETRA sequence to acquire fat-suppressed 3D T_1ρ -weighted images tissues with semisolid short T₂ / T2* relaxation times in the knee and ankle joints at 3 T.

ASSESSMENT: Mono- and biexponential T_1ρ relaxation components were assessed in the patellar tendon (PT), anterior cruciate ligament (ACL), posterior cruciate ligament (PCL), and Achilles tendon (AT).

STATISTICAL TESTS: Kruskal-Wallis with post-hoc Dunn's test for multiple pairwise comparisons.

RESULTS: Phantom and ex vivo studies showed the feasibility of T_1ρ relaxation mapping using the proposed 3D-T_1ρ -PETRA sequence. The in vivo study demonstrated an averaged mono-T_1ρ relaxation of (median [IQR]) 15.9 [14.5] msec, 23.6 [9.4] msec, 17.4 [7.4] msec, and 5.8 [10.2] msec in the PT, ACL, PCL, and AT, respectively. The bicomponent analysis showed the short and long components (with their relative fractions) of 0.65 [1.0] msec (46.9 [15.3]%) and 37.3 [18.4] msec (53.1 [15.3]%) for PT, 1.7 [2.1] msec (42.5 [12.5]%) and 43.7 [17.8] msec (57.5 [12.5]%) for ACL, and 1.2 [1.9] msec (42.6 [14.0]%) and 27.7 [14.7] msec (57.3 [14.0]%) for PCL and 0.4 [0.02] msec (58.8 [13.3]%/) and 31.3 [10.8] msec (41.2 [13.3]%) for AT. Statistically significant (P ≤ 0.05) differences were observed in the mono- and biexponential relaxation between several regions.

DATA CONCLUSION: The 3D-T_1ρ -PETRA sequence allows volumetric, isotropic (0.78 × 0.78 × 0.78 mm), biexponential T_1ρ assessment with corresponding fractions of the tissues with semisolid short T₂ / T2* .

LEVEL OF EVIDENCE: 2 Technical Efficacy Stage: 1 J. Magn. Reson. Imaging 2019;50:1207-1218.

Author List

Sharafi A, Baboli R, Chang G, Regatte RR

Author

Azadeh Sharafi PhD Assistant Professor in the Radiology department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Achilles Tendon
Adult
Animals
Ankle Joint
Cattle
Feasibility Studies
Female
Healthy Volunteers
Humans
Image Processing, Computer-Assisted
Imaging, Three-Dimensional
Knee Joint
Magnetic Resonance Imaging
Male
Models, Animal
Phantoms, Imaging
Prospective Studies
Reference Values