Fat-suppressed T-2 mapping of femoral cartilage in the porcine knee joint: A comparison with conventional T-2 mapping

Abstract

PurposeTo investigate the effect of fat suppression on T-2 mapping of the articular cartilage in the porcine knee joint using magnetic resonance imaging (MRI). Materials and MethodsEleven porcine knee joints were harvested en bloc with intact capsules. We performed T-2 mapping of the articular cartilage in the medial femoral condyle at 3T either with (fat-suppressed T-2 mapping) or without (conventional T-2 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 T-2 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 T-2 mapping by changing the frequency-encoding direction. ResultsThe mean T-2 values of fat-suppressed T-2 mapping were significantly lower than those of conventional T-2 mapping for five of eight comparisons (P < 0.017). The mean T-2 values between fat-suppressed T-2-SI and fat-suppressed T-2-IS did not differ significantly in any region (P=0.077-0.873). However, the mean T-2 values of conventional T-2-SI were significantly lower compared with conventional T-2-IS in three of the regions (P < 0.05). The intraclass correlation coefficient (ICC) between the two fat-suppressed T-2 maps was higher than the ICC between the two conventional T-2 maps (0.276-0.800 vs. -0.032-0.455) for three regions. ConclusionCompared with conventional T-2 mapping, fat-suppressed T-2 mapping provides lower T-2 values of the articular cartilage and more reproducible results for the porcine knee joint.