应用MRS和R2^＊半定量法评价服用枫树油对MRI检查的影响

Semi-quantitative assessment of influence of maple oil to MRI examination by MR spectroscopy and R2^＊ measurement

目的研究枫树油对MRI检查的影响及其原因。方法MRS实验选取枫树油与相同条件下的豆油作为对照研究。临床实验选择5名志愿者每天空腹一次性服用10ml枫树油,连续服用6天（短期组）。服用前和服用后30min分别进行两次MR扫描。这些志愿者分别在其他时间段内服用水作对照研究。在相同的ROI测量肝脏、肌肉和肠的R2^＊值。另外,对两名服用2年枫树油的志愿者进行常规MR扫描。结果1HMRS数据显示,枫树油与豆油具有相同的化学复合物成分。与豆油相比,在相同的环境条件与扫描条件下,枫树油CH2峰的线宽增加44%,表明枫树油溶液中有磁性物质影响磁场均匀性。短期服用枫树油组,服用前后肝脏和肌肉R2^＊值没有明显的统计学差异,但肠道R2^＊值与服用前相比明显增加,并可见明显的磁敏感伪影。服用水和豆油组,服用前后未见显著性差异。长期服用枫树油,肝脏的中心频率明显高于正常人群。结论通过R2^＊值的测量,可以看出,短期服用枫树油主要存在于胃肠道系统中。长期服用,枫树油的成分可能转移并储存到肝组织,造成扫描中心频率的偏移。其有效成份和转移路径还在进一步研究中。

Objective To study the influence of maple oil consumption on MRI examination by using MRS and R2^＊ measurement. Methods Maple oil was compared with normal bean oil by 1H MRS examination under same condition. Five healthy volunteers took 10 ml maple oil simultaneously one time a day and repeated in 5 consecutive days. MR examinations were performed before the oil taken and 30 minutes after, including axial T2, coronal FIESTA and axial multi-echo GRE for R2^＊ calculation （8 echoes）. Water drinking and bean oil drinking were also included on a separate day for comparison. Liver, muscle, intestine＇s R2^＊ value （in Hz） were measured with identical ROI. Two healthy volunteers who took Maple oil for 2 years were examined by routine MR protocol. Results From 1H MRS data, maple oil had identical chemical compound as bean oil, but higher none saturated lipid concentration. Also the line width of the CH2 peak of maple oil was 44% bigger than normal bean oil, which was possible due to regional field inhomogeneity caused by its ingredient. For the short term oil taken group, the R2^＊ values of liver and muscle did not have statistical difference before and after oil taken, but noticeable mental artifact could be observed in intestinal area and its R2^＊ value increased after oil taken. No statistical differences during the water drink and bean oil drink examination. For the long-term oil taken group, the center frequency of liver was much bigger than other patients or volunteers. Conclusion From R2^＊ value, we can easily tell that short-term consumption of maple oil is in gastrointestinal system. From the long-term study group, it is possible that part of maple oil will be transported and stored in liver system, which causes the shift of center frequency. The effected ingredient and its pathway are under investigation.