Integrated Research and Treatment Center (IFB) AdiposityDiseases, Leipzig University Medical Center, Leipzig, Germany.
Department of Diagnostics, Fraunhofer Institute for Cell Therapy and Immunology, Leipzig, Germany.
PLoS One. 2018 Nov 2;13(11):e0206735. doi: 10.1371/journal.pone.0206735. eCollection 2018.
Bariatric surgery and other therapeutic options for obese patients are often evaluated by the loss of weight, reduction of comorbidities or improved quality of life. However, little is currently known about potential therapy-related changes in the adipose tissue of obese patients. The aim of this study was therefore to quantify fat fraction (FF) and T1 relaxation time by magnetic resonance imaging (MRI) after Roux-en-Y gastric bypass surgery and compare the resulting values with the preoperative ones. Corresponding MRI data were available from 23 patients (16 females and 7 males) that had undergone MRI before (M0) and one month after (M1) bariatric surgery. Patients were 22-59 years old (mean age 44.3 years) and their BMI ranged from 35.7-54.6 kg/m2 (mean BMI 44.6 kg/m2) at M0. Total visceral AT volumes (VVAT-T, in L) were measured by semi-automatic segmentation of axial MRI images acquired between diaphragm and femoral heads. MRI FF and T1 relaxation times were measured in well-defined regions of visceral (VAT) and subcutaneous (SAT) adipose tissue using two custom-made analysis tools. Average BMI values were 45.4 kg/m2 at time point M0 and 42.4 kg/m2 at M1. Corresponding VVAT-T values were 5.94 L and 5.33 L. Intraindividual differences in both BMI and VVAT-T were highly significant (p<0.001). Average relaxation times T1VAT were 303.7 ms at M0 and 316.9 ms at M1 (p<0.001). Corresponding T1SAT times were 283.2 ms and 280.7 ms (p = 0.137). Similarly, FFVAT differences (M0: 85.7%, M1: 83.4%) were significant (p <0.01) whereas FFSAT differences (M0: 86.1, M1: 85.9%) were not significant (p = 0.517). In conclusion, bariatric surgery is apparently not only related to a significant reduction in common parameters of adipose tissue distribution, here BMI and total visceral fat volume, but also significant changes in T1 relaxation time and fat fraction of visceral adipose tissue. Such quantitative MRI measures may potentially serve as independent biomarkers for longitudinal and cross-sectional measurements in obese patients.
减重手术和其他治疗肥胖患者的方法通常通过体重减轻、减少合并症或提高生活质量来评估。然而，目前对于肥胖患者脂肪组织的潜在治疗相关变化知之甚少。因此，本研究的目的是通过磁共振成像 (MRI) 定量测量 Roux-en-Y 胃旁路手术后的脂肪分数 (FF) 和 T1 弛豫时间，并将所得值与术前值进行比较。这项研究共纳入了 23 名患者（16 名女性和 7 名男性），这些患者在接受减重手术前 (M0) 和术后一个月 (M1) 进行了 MRI 检查。患者年龄为 22-59 岁（平均年龄 44.3 岁），M0 时 BMI 范围为 35.7-54.6 kg/m2（平均 BMI 为 44.6 kg/m2）。通过对膈肌和股骨头之间获得的轴向 MRI 图像进行半自动分割，测量总内脏脂肪体积 (VVAT-T，以升计)。使用两个定制的分析工具，在内脏 (VAT) 和皮下 (SAT) 脂肪组织的确定区域测量 MRI FF 和 T1 弛豫时间。M0 时平均 BMI 值为 45.4 kg/m2，M1 时为 42.4 kg/m2。相应的 VVAT-T 值分别为 5.94 L 和 5.33 L。BMI 和 VVAT-T 的个体内差异均具有高度显著性（p<0.001）。M0 时 VAT 的平均弛豫时间 T1VAT 为 303.7 ms，M1 时为 316.9 ms（p<0.001）。相应的 T1SAT 时间分别为 283.2 ms 和 280.7 ms（p = 0.137）。同样，VAT 的 FF 差异（M0：85.7%，M1：83.4%）具有显著性（p <0.01），而 SAT 的 FF 差异（M0：86.1，M1：85.9%）无显著性（p = 0.517）。总之，减重手术不仅与 BMI 和总内脏脂肪体积等脂肪组织分布的常见参数的显著减少有关，还与内脏脂肪组织的 T1 弛豫时间和脂肪分数的显著变化有关。这些定量 MRI 测量可能可作为肥胖患者纵向和横向测量的独立生物标志物。
