Ishizaka H, Tomiyoshi K, Matsumoto M, Inoue T
Department of Diagnostic Radiology, Gunma University Hospital, Japan.
Invest Radiol. 1994 Mar;29(3):361-3. doi: 10.1097/00004424-199403000-00019.
Chemical-shift artifact occurs within tissues when band-like presaturation pulses are applied perpendicular to the frequency-encoding axis in narrow band-width magnetic resonance imaging. This phenomenon was used to quantify the lipid fraction in phantoms used to simulate tissue.
Twenty phantoms with various lipid/water ratios were imaged on spin-echo sequence (repetition time/echo time, 2,000/20 msec) using a 1.5-T magnet. A narrow bandwidth that caused 6-mm chemical shift and a presaturation pulse 6-mm in width were used in the imagining. The lipid fraction values calculated from the resulting images were compared with values determined by a spectrometer.
The image-derived values (LI) correlated strongly with the values determined by spectrometry (LS) (LI = 0.97 + 0.99 LS, r = .998).
Chemical-shift artifact around the presaturation-applied areas should provide a simple and efficient method for the accurate quantification of tissue lipid fractions.
在窄带宽磁共振成像中，当带状预饱和脉冲垂直于频率编码轴施加时，组织内会出现化学位移伪影。这种现象被用于量化模拟组织的模型中的脂质分数。
使用1.5-T磁体，在自旋回波序列（重复时间/回波时间，2000/20毫秒）上对20个具有不同脂质/水比例的模型进行成像。在成像中使用了导致6毫米化学位移的窄带宽和宽度为6毫米的预饱和脉冲。将从所得图像计算出的脂质分数值与通过光谱仪测定的值进行比较。
图像得出的值（LI）与光谱法测定的值（LS）高度相关（LI = 0.97 + 0.99 LS，r = 0.998）。
预饱和施加区域周围的化学位移伪影应为准确量化组织脂质分数提供一种简单有效的方法。
