Fat-suppressed T2 mapping of femoral cartilage in the porcine knee joint: A comparison with conventional T2 mapping.

Purpose To investigate the effect of fat suppression on T2 mapping of the articular cartilage in the porcine knee joint using magnetic resonance imaging (MRI). Materials and Methods Eleven porcine knee joints were harvested en bloc with intact capsules. We performed T2 mapping of the articular cartilage in the medial femoral condyle at 3T either with (fat-suppressed T2 mapping) or without (conventional T2 mapping) fat suppression in the sagittal plane under two frequency-encoding directions: from superior to inferior (SI) and inferior to superior (IS). Two observers measured the T2 values of the medial femoral condyle cartilage in four regions: in the anterior oblique, central horizontal, posterior oblique, and posterior vertical portions. We evaluated reproducibility of the fat-suppressed and conventional T2 mapping by changing the frequency-encoding direction. Results The mean T2 values of fat-suppressed T2 mapping were significantly lower than those of conventional T2 mapping for five of eight comparisons (P < 0.017). The mean T2 values between fat-suppressed T2-SI and fat-suppressed T2-IS did not differ significantly in any region (P = 0.077–0.873). However, the mean T2 values of conventional T2-SI were significantly lower compared with conventional T2-IS in three of the regions (P < 0.05). The intraclass correlation coefficient (ICC) between the two fat-suppressed T2 maps was higher than the ICC between the two conventional T2 maps (0.276–0.800 vs. –0.032–0.455) for three regions. Conclusion Compared with conventional T2 mapping, fat-suppressed T2 mapping provides lower T2 values of the articular cartilage and more reproducible results for the porcine knee joint. J. Magn. Reson. Imaging 2016.