Duewell S H, Ceckler T L, Ong K, Wen H, Jaffer F A, Chesnick S A, Balaban R S
Laboratory of Cardiac Energetics, National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
Radiology. 1995 Aug;196(2):551-5. doi: 10.1148/radiology.196.2.7617876.
To evaluate the relaxation time-based contrast between the main tissues of the musculoskeletal system as measured in the human knee with magnetic resonance imaging at 4 T and 1.5 T.
Five volunteers underwent 4-T and 1.5-T imaging. Inversion-recovery series were used to measure T1 values, and T2 values were measured with a spin-echo sequence.
T1 values increased in all tissues with 4-T imaging. Values increased in muscle from 1 to 1.8 seconds, in fat from 0.3 to 0.4 seconds, and in cartilage from 0.8 to 1.5 seconds. T2 values were 10%-20% shorter in all tissues at 4 T.
Advantages of 4-T imaging compared with 1.5-T imaging include a higher signal-to-noise ratio and an improved signal difference-to-noise ratio. However, any improvement in signal-to-noise ratio at high field strengths can partially be reduced by the increase in the T1 value. The slightly shorter T2 values at 4 T do not affect image contrast.
评估在4T和1.5T磁场强度下，通过磁共振成像测量人体膝关节肌肉骨骼系统主要组织基于弛豫时间的对比度。
五名志愿者接受了4T和1.5T成像。采用反转恢复序列测量T1值，用自旋回波序列测量T2值。
4T成像时所有组织的T1值均增加。肌肉的T1值从1秒增加到1.8秒，脂肪从0.3秒增加到0.4秒，软骨从0.8秒增加到1.5秒。4T时所有组织的T2值缩短10%-20%。
与1.5T成像相比，4T成像的优势包括更高的信噪比和改善的信号差异与噪声比。然而，高场强下信噪比的任何改善会因T1值增加而部分降低。4T时稍短的T2值不影响图像对比度。
