3T MRI of the knee with optimised isotropic 3D sequences: Accurate delineation of intra-articular pathology without prolonged acquisition times

• Published in: European radiology Vol. 27; no. 11; pp. 4563 - 4570
• Main Authors: Abdulaal, Osamah M., Rainford, Louise, MacMahon, Peter, Kavanagh, Eoin, Galligan, Marie, Cashman, James, McGee, Allison
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-11-2017; Springer Nature B.V
• Subjects: Abnormalities; Adult; Aged; Cartilage; Cartilage (articular); Cartilage, Articular - pathology; Defects; Diagnostic Radiology; Female; Humans; Imaging; Imaging, Three-Dimensional - methods; Internal Medicine; Interventional Radiology; Joint Diseases - diagnosis; Knee; Knee Joint - pathology; Lesions; Magnetic Resonance; Magnetic resonance imaging; Magnetic Resonance Imaging - methods; Male; Medicine; Medicine & Public Health; Meniscus; Middle Aged; Neuroradiology; Proton density (concentration); Radiology; Reproducibility of Results; Ultrasound; Young Adult; Knee joint; Cartilage; Articular; Magnetic resonance imaging; Evidence-based practice
• ISSN: 0938-7994; 1432-1084
• DOI: 10.1007/s00330-017-4816-x

Objectives
To investigate optimised isotropic 3D turbo spin echo (TSE) and gradient echo (GRE)-based pulse sequences for visualisation of articular cartilage lesions within the knee joint.
Methods
Optimisation of experimental imaging sequences was completed using healthy volunteers (n=16) with a 3-Tesla (3T) MRI scanner. Imaging of patients with knee cartilage abnormalities (n=57) was then performed. Acquired sequences included 3D proton density-weighted (PDW) TSE (SPACE) with and without fat-suppression (FS), and T2*W GRE (TrueFISP) sequences, with acquisition times of 6:51, 6:32 and 5:35 min, respectively.
Results
One hundred sixty-one confirmed cartilage lesions were detected and categorised (Grade II n=90, Grade III n=71). The highest sensitivity and specificity for detecting cartilage lesions were obtained with TrueFISP with values of 84.7% and 92%, respectively. Cartilage SNR mean for PDW SPACE-FS was the highest at 72.2. TrueFISP attained the highest CNR means for joint fluid/cartilage (101.5) and joint fluid/ligament (156.5), and the lowest CNR for cartilage/meniscus (48.5). Significant differences were identified across the three sequences for all anatomical structures with respect to SNR and CNR findings (p-value <0.05).
Conclusion
Isotropic TrueFISP at 3T, optimised for acquisition time, accurately detects cartilage defects, although it demonstrated the lowest contrast between cartilage and meniscus.
Key points
• Cartilage is better visualised with 3D TrueFISP than 3D SPACE sequences.
• 3D TrueFISP is a reliable sequence for detecting low- and high-grade cartilage defects.
• 3D TrueFISP at 3T provides excellent contrast between cartilage and joint fluid.