Knee osteochondral junction imaging using a fast 3D T1-weighted ultrashort echo time cones sequence at 3T

Zhenyu Cai; Zhao Wei; Mei Wu; Saeed Jerban; Hyungseok Jang; Shaolin Li; Xuchun Yuan; Ya-Jun Ma

doi:10.1016/j.mri.2020.08.003

Knee osteochondral junction imaging using a fast 3D T₁-weighted ultrashort echo time cones sequence at 3T

Magn Reson Imaging. 2020 Nov:73:76-83. doi: 10.1016/j.mri.2020.08.003. Epub 2020 Aug 21.

Authors

Zhenyu Cai¹, Zhao Wei², Mei Wu², Saeed Jerban², Hyungseok Jang², Shaolin Li³, Xuchun Yuan⁴, Ya-Jun Ma⁵

Affiliations

¹ Department of Radiology, Fuwai Hospital Chinese Academy of Medical Sciences, Guangdong, China; Department of Radiology, University of California, San Diego, CA, USA.
² Department of Radiology, University of California, San Diego, CA, USA.
³ Department of Radiology, The Fifth Affiliated Hospital of Sun Yat-Sen University, Guangdong, China.
⁴ Department of Radiology, Fuwai Hospital Chinese Academy of Medical Sciences, Guangdong, China.
⁵ Department of Radiology, University of California, San Diego, CA, USA. Electronic address: yam013@ucsd.edu.

Abstract

The osteochondral junction (OCJ) of the knee joint is comprised of multiple tissue components, including a portion of the deep layer cartilage, calcified cartilage, and subchondral bone. The OCJ is of increasing radiological interest as it may be relevant in the early pathogenesis of osteoarthritis (OA). Due to its short transverse relaxation, the OCJ is invisible to clinical MR sequences. The purpose of this study was to develop a fast 3D T₁-weighted ultrashort echo time cones sequence with fat saturation (FS-UTE-Cones) for high resolution and high contrast imaging of the OCJ on a clinical 3T scanner. First, numerical simulations were performed to investigate how the flip angle affected the signal intensities and contrasts of both short and long T₁ tissues. The results from these simulations demonstrated that higher short T₁ contrast could be achieved with higher flip angle. Next, T₁ relaxation was measured for the different layers of a human patellar cartilage sample, and the results showed that the deepest layer had a significantly shorter T₁ value than other layers. Finally, a healthy knee joint was scanned with different flip angles and the OCJ was highlighted in the T₁-weighted FS-UTE-Cones sequence using a flip angle greater than 20°. The clinical T₂-weighted and proton density-weighted FSE sequences were also included for comparison, revealing a dark OCJ region. Representative T₁-weighted FS-UTE-Cones images of the whole knee of a healthy volunteer showed high signal intensity bands in the OCJ regions of the patella, femur, and tibia. On the other hand, T₁-weighted FS-UTE-Cones imaging of the knee joints of OA patients revealed regions with reduction or loss of these high signal intensity bands in the OCJ regions, indicating abnormal OCJ tissue composition. The proposed 3D T₁-weighted FS-UTE-Cones sequence with a 3-min scan time may be very useful for demonstrating the involvement of the OCJ regions in early OA.

Keywords: 3D ultrashort echo time; Osteochondral junction; T(1)-weighted.

Publication types

Research Support, N.I.H., Extramural
Research Support, Non-U.S. Gov't

MeSH terms

Adult
Cartilage / diagnostic imaging
Female
Humans
Imaging, Three-Dimensional*
Knee Joint / diagnostic imaging*
Magnetic Resonance Imaging*
Male
Middle Aged
Time Factors

Abstract

Publication types

MeSH terms

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