Kornaat P R, Reeder S B, Koo S, Brittain J H, Yu H, Andriacchi T P, Gold G E
Department of Radiology, Stanford University, Stanford, CA, USA.
Osteoarthritis Cartilage. 2005 Apr;13(4):338-44. doi: 10.1016/j.joca.2004.12.008.
To compare articular cartilage signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and thickness measurements on a 1.5 T and a 3.0 T magnetic resonance (MR) scanner using three-dimensional spoiled gradient recalled echo (3D-SPGR) and two 3D steady-state free precession (SSFP) sequences.
Both knees of five volunteers were scanned at 1.5 T and at 3.0 T using a transmit-receive quadrature extremity coil. Each examination consisted of a sagittal 3D-SPGR sequence, a sagittal fat suppressed 3D-SSFP (FS-SSFP) sequence, and a sagittal Dixon 3D-SSFP sequence. For quantitative analysis, we compared cartilage SNR and CNR efficiencies, as well as average cartilage thickness measurements.
For 3D-SPGR, cartilage SNR efficiencies at 3.0 T increased compared to those at 1.5 T by a factor of 1.83 (range: 1.40-2.09). In comparison to 3D-SPGR, the SNR efficiency of FS-SSFP increased by a factor of 2.13 (range: 1.81-2.39) and for Dixon SSFP by a factor of 2.39 (range: 1.95-2.99). For 3D-SPGR, CNR efficiencies between cartilage and its surrounding tissue increased compared to those at 1.5 T by a factor of 2.12 (range: 1.75-2.47), for FS-SSFP by a factor 2.11 (range: 1.58-2.80) and for Dixon SSFP by a factor 2.39 (range 2.09-2.83). Average cartilage thicknesses of load bearing regions were not different at both field strengths or between sequences (P>0.05). Mean average cartilage thickness measured in all knees was 2.28 mm.
Articular cartilage imaging of the knee on a 3.0 T MR scanner shows increased SNR and CNR efficiencies compared to a 1.5 T scanner, where SSFP-based techniques show the highest increase in SNR and CNR efficiency. There was no difference between average cartilage thickness measurements performed at the 1.5 T and 3.0 T scanners or between the three different sequences.
使用三维扰相梯度回波（3D-SPGR）序列和两个三维稳态自由进动（SSFP）序列，比较1.5T和3.0T磁共振（MR）扫描仪上关节软骨的信噪比（SNR）、对比噪声比（CNR）及厚度测量值。
使用收发一体式正交肢体线圈对5名志愿者的双侧膝关节在1.5T和3.0T场强下进行扫描。每次检查包括矢状位3D-SPGR序列、矢状位脂肪抑制三维稳态自由进动（FS-SSFP）序列和矢状位狄克逊三维稳态自由进动（Dixon SSFP）序列。进行定量分析时，我们比较了软骨的SNR和CNR效率，以及平均软骨厚度测量值。
对于3D-SPGR序列，3.0T场强下软骨的SNR效率相较于1.5T场强提高了1.83倍（范围：1.40 - 2.09）。与3D-SPGR序列相比，FS-SSFP序列的SNR效率提高了2.13倍（范围：1.81 - 2.39），Dixon SSFP序列的SNR效率提高了2.39倍（范围：1.95 - 2.99）。对于3D-SPGR序列，软骨与其周围组织之间的CNR效率相较于1.5T场强提高了2.12倍（范围：1.75 - 2.47），FS-SSFP序列提高了2.11倍（范围：1.58 - 2.80），Dixon SSFP序列提高了2.39倍（范围：2.09 - 2.83）。在两种场强下或不同序列之间，承重区域的平均软骨厚度无差异（P>0.05）。所有膝关节测量的平均软骨厚度为2.28mm。
与1.5T扫描仪相比，在3.0T MR扫描仪上进行膝关节软骨成像时，SNR和CNR效率有所提高，其中基于SSFP的技术在SNR和CNR效率方面提高最为显著。在1.5T和3.0T扫描仪上进行的平均软骨厚度测量以及三种不同序列之间均无差异。
