A simplified method of T(1)ρ mapping in clinical assessment of knee joint
Yukihisa Takayama1, Masamitsu Hatakenaka, Takashi Yoshiura
1Department of Clinical Radiology, Graduate School of Medical Sciences, Kyushu University, Higashi-ku, Fukuoka, Japan. ytaka@radiol.med.kyushu-u.ac.jp
Purpose:
we assessed the clinical utility of our proposed simplified method for T(1)ρ mapping calculations.
Materials And Methods:
ten healthy subjects underwent scanning on a 3-tesla magnetic resonance system using an 8-channel phased-array coil. For each subject, we obtained sagittal T(1)ρ-prepared images using 5 different time of spin-lock pulses (TSL=1, 20, 40, 60, and 80 ms), produced conventional T(1)ρ maps (cT(1)ρ maps) using all TSLs, and recomputed our proposed simplified T(1)ρ maps (sT(1)ρ maps) using a decreasing number of TSLs (from 4 to 2). We then investigated the differences and correlations in T(1)ρ values of the tissues obtained using different numbers of spin-lock times.
Results:
there was a strong positive correlation (single measure intraclass correlation coefficient=0.948; 95% confidence interval=0.911 to 0.970) in T(1)ρ values of tissues between the cT(1)ρ and sT(1)ρ [1, 80] maps. The 2 maps were comparable, though there was a small difference in T(1)ρ value between the two. The total scan time to acquire the data from 5 spin-lock times was 16 min 15 s. Similarity of the T(1)ρ [1, 80] map with the conventional approach reduced scan time by 60%, to 6 min 30 s.
Conclusion:
the clinical relevance of our proposed simplified method is potentially similar to that of the conventional method, and our method requires a shorter examination time and generally preserves the reliability of the T(1)ρ relaxation time of the tissues.
