Study of comparing the multiple MR sequenc in the articular cartilage of knee joint

Abstract

To investigate the value of various MR imaging sequences for the assessment of articular cartilage and to determine the most optional sequence. MR sagittal scanning of knee joints were performed in nine fresh bovine models. MR scan sequences consisted of TSE-T(1)WI, TSE-T(2)WI, TSE-PDWI, 3D-FFE-T(1)WI, 3D-BFFE, TSE-T(1)WI-SPIR, TSE-T(2)WI-SPIR, TSE-PDWI-SPIR, 3D-FFE-SPIR, 3D-FFE-WATS, 3D-FFE-MTC, 3D-BFFE-WATS. The signal noise ratio (SNR) and contrast noise ratio (CNR) between cartilage and adjacent tissue were calculated and compared. The knees of fifteen healthy volunteers were imaged with the selective MR sequences and the SNR, CNR and their efficiency were calculated and analyzed statistically. In bovine knee models, the cartilage SNR was higher in the sequences which attached SPIR, WATS and MTC than that of without these techniques. There was a statistically significant difference. The CNR between cartilage and adjacent tissue was also higher in the former. In healthy volunteers, the cartilage SNR was better in 3D-FFE-SPIR, 3D-FFE-WATS, 3D-BFFE-WATS. CNR between cartilage and bone, marrow, muscle, fat were better in 3D-FFE-SPIR, 3D-FFE-WATS, 3D-BFFE-WATS; CNR between cartilage and liquid was better in 3D-FFE-WATS, TSE-T2WI-SPIR, TSE-PDWI-SPIR; CNR between cartilage and meniscus, ligament was better in 3D-FFE-SPIR, 3D-BFFE-WATS, TSE-PDWI-SPIR. The SNR and CNR efficiency were higher in 3D-FFE-WATS, 3D-BFFE-WATS, 3D-FFE-SPIR. There was a statistical difference between these sequences and others (P < 0.01). The cartilage SNR and CNR between cartilage and bone, muscle of 3D-FFE-SPIR weren't significantly higher than that of 3D-FFE-WATS (P > 0.05); CNR between cartilage and liquid, marrow, fat were higher in 3D-FFE-WATS and significantly different than that of 3D-FFE-SPIR (P < 0.01). Articular cartilage SNR and CNR between cartilage and its surrounding tissue are higher in sequences attached SPIR, WATS, so fat suppress technique should routinely be used in clinical cartilage examination. WATS has high scan speed and suppress the fat signal evenly, so it can substitute SPIR. 3D-FFE-WATS is one of the most sensitive sequences in showing cartilage shape and detecting its injury. The cartilage SNR, the CNR between cartilage and adjacent tissue and their efficiency are high in 3D-BFFE-WATS and it can be used in the clinical examination.