High-resolution cartilage imaging of the knee at 3T: basic evaluation of modern isotropic 3D MR-sequences.
OBJECTIVE
To evaluate qualitative and quantitative image quality parameters of isotropic three-dimensional (3D) cartilage-imaging magnetic resonance (MR)-sequences at 3T.


METHODS
The knees of 10 healthy volunteers (mean age, 24.4±5.6 years) were scanned at a 3T MR scanner with water-excited 3D Fast-Low Angle Shot (FLASH), True Fast Imaging with Steady-state Precession (TrueFISP), Sampling Perfection with Application-optimized Contrast using different flip-angle Evolutions (SPACE) as well as conventional and two individually weighted Double-Echo Steady-State (DESS) sequences. The MR images were evaluated qualitatively and quantitatively (signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), SNR efficiency, CNR efficiency). Quantitative parameters were compared by means of a Tukey-test and sequences were ranked according to SNR/CNR, SNR/CNR efficiency and qualitative image grading.


RESULTS
The highest SNR was measured for SPACE (34.0±5.6), the highest CNR/CNR efficiency (cartilage/fluid) for the individually weighted DESS (46.9±18.0/2.18±0.84). SPACE, individually weighted and conventional DESS were ranked best with respect to SNR/CNR and SNR/CNR efficiency. The DESS sequences also performed best in the qualitative evaluation. TrueFISP performed worse, FLASH worst. The individually weighted DESS sequences were generally better than the conventional DESS with the significant increase of cartilage-fluid contrast (46.9±18.0/31.9±11.4 versus 22.0±7.3) as main advantage.


CONCLUSIONS
Individually weighted DESS is the most promising candidate; all tested sequences performed better than FLASH.
MR Centre of Excellence, Division of Neuroradiology and Musculoskeletal Radiology, Department of Radiology, Medical University of Vienna, Waehringer Guertel 18-20, A-1090 Vienna, Austria. klaus.friedrich@meduniwien.ac.at
Klaus M
KM
Friedrich
Gert
G
Reiter
Bernd
B
Kaiser
Marius
M
Mayerhöfer
Michael
M
Deimling
Vladimir
V
Jellus
Wilhelm
W
Horger
Siegfried
S
Trattnig
Mark
M
Schweitzer
Erich
E
Salomonowitz
D000465:Algorithms; D002358:Cartilage, Articular / Q000033:anatomy & histology*; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D007719:Knee Joint / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult