Hayashi Tatsuya, Fukuzawa Kei, Kondo Hiroshi, Onodera Hiroshi, Toyotaka Shuji, Tojo Rie, Yano Shimpei, Tano Masakatsu, Miyati Tosiaki, Kotoku Jun'ichi, Okamoto Takahide, Toyoda Keiko, Oba Hiroshi
Graduate School of Medical Technology, Teikyo University, 2-11-1 Kaga, Itabashi-ku, Tokyo, 173-8605, Japan.
Department of Radiological Technology, Toranomon Hospital, Tokyo, Japan.
Radiol Phys Technol. 2017 Dec;10(4):483-488. doi: 10.1007/s12194-017-0420-7. Epub 2017 Sep 11.
The purpose of this study was to evaluate whether disodium gadoxetate (Gd-EOB-DTPA) affects proton density fat fractions (PDFFs) during use of the multiecho Dixon (meDixon) method in phantom and simulation magnetic resonance imaging (MRI) studies at 3 T. Fat-water phantoms comprising vegetable fat-water emulsions with varying fat volume percentages (0, 5, 10, 15, 20, 30, 40, and 50) and Gd-EOB-DTPA concentrations (0 and 0.4 mM) were prepared. Phantoms without Gd-EOB-DTPA were defined as precontrast, and those with Gd-EOB-DTPA were defined as postcontrast. All phantoms were scanned with a 3 T MRI system using the meDixon method, and precontrast and postcontrast PDFFs were calculated. Simulated pre and postcontrast PDFFs in the liver were calculated using a theoretical formula. The relationship between PDFFs measured in the pre and postcontrast phantoms was evaluated using linear regression and Bland-Altman analysis. The regression analysis comparing the pre and postcontrast PDFFs yielded a slope of 0.77 (P < 0.001). The PDFFs on the postcontrast phantom were smaller than those on the precontrast phantom. The mean difference between the PDFFs on the pre and postcontrast phantoms was 6.12% (95% confidence interval 3.13 to 9.10%; limits of agreement -0.88 to 13.11%). The simulated PDFF on the postcontrast phantom was smaller than that on the precontrast phantom. We demonstrated that the PDFF measured using the meDixon was smaller on postcontrast than on precontrast at 3 T, if a low flip angle was used. This tendency was also seen in the simulation study results.
本研究的目的是评估钆塞酸二钠（Gd-EOB-DTPA）在3T体模和模拟磁共振成像（MRI）研究中使用多回波狄克逊（meDixon）方法时是否会影响质子密度脂肪分数（PDFF）。制备了包含不同脂肪体积百分比（0、5、10、15、20、30、40和50）以及Gd-EOB-DTPA浓度（0和0.4 mM）的植物脂肪-水乳液的脂肪-水体模。不含Gd-EOB-DTPA的体模定义为造影前体模，含Gd-EOB-DTPA的体模定义为造影后体模。使用meDixon方法对所有体模进行3T MRI系统扫描，并计算造影前和造影后的PDFF。使用理论公式计算肝脏中模拟的造影前和造影后PDFF。使用线性回归和布兰德-奥特曼分析评估造影前和造影后体模中测量的PDFF之间的关系。比较造影前和造影后PDFF的回归分析得出斜率为0.77（P < 0.001）。造影后体模上的PDFF小于造影前体模上的PDFF。造影前和造影后体模上PDFF的平均差异为6.12%（95%置信区间3.13%至9.10%；一致性界限为-0.88%至13.11%）。造影后体模上模拟的PDFF小于造影前体模上的模拟PDFF。我们证明，如果使用低翻转角，在3T时使用meDixon测量的造影后PDFF小于造影前PDFF。在模拟研究结果中也观察到了这种趋势。
