Ly Karrie V, Armstrong Tess, Yeh Joanna, Ghahremani Shahnaz, Kim Grace H, Wu Holden H, Calkins Kara L
Division of Neonatology and Developmental Biology, Department of Pediatrics, Neonatal Research Center.
Department of Radiological Sciences.
J Pediatr Gastroenterol Nutr. 2019 Jun;68(6):782-787. doi: 10.1097/MPG.0000000000002309.
Conventional, breath-holding magnetic resonance imaging (MRI) assesses body composition by measuring fat volumes and proton density fat fraction (PDFF). However, breath-holding MRI is not always feasible in children. This study's objective was to use free-breathing MRI to quantify visceral and subcutaneous fat volumes and PDFFs and correlate these measurements with hepatic PDFF.
This was an observational, hypothesis-forming study that enrolled 2 groups of children (ages 6-17 years), healthy children and overweight children with presumed nonalcoholic fatty liver disease. Free-breathing MRI was used to measure visceral and subcutaneous fat volumes and PDFFs, and hepatic PDFF. Imaging biomarkers were compared between groups, and correlations coefficients (r) and coefficients of determination (R) were calculated.
When compared with the control group (n = 10), the overweight group (n = 9) had greater mean visceral (1843 vs 329 cm, P < 0.001) and subcutaneous fat volumes (7663 vs 893 cm, P < 0.001), as well as greater visceral (80% vs 45%, p < 0.001) and subcutaneous fat PDFFs (89% vs 75%, P = 0.003). Visceral fat volume (r = 0.79, P < 0.001) and PDFF (r = 0.92, P < 0.001) correlated with hepatic PDFF. In overweight subjects, for each unit increase in visceral fat PDFF, hepatic PDFF increased by 2.64%; visceral fat PDFF explained 54% of hepatic PDFF variation (R = 0.54, P = 0.02).
In this study, we used free-breathing MRI to measure body composition in children. Future studies are needed to investigate the possible value of subcutaneous and visceral fat PDFFs, and validate free-breathing MRI body composition biomarkers.
传统的屏气磁共振成像（MRI）通过测量脂肪体积和质子密度脂肪分数（PDFF）来评估身体成分。然而，屏气MRI在儿童中并不总是可行的。本研究的目的是使用自由呼吸MRI来量化内脏和皮下脂肪体积及PDFF，并将这些测量值与肝脏PDFF进行关联。
这是一项观察性、形成假设的研究，纳入了两组儿童（6 - 17岁），即健康儿童和疑似非酒精性脂肪性肝病的超重儿童。使用自由呼吸MRI测量内脏和皮下脂肪体积及PDFF，以及肝脏PDFF。比较两组之间的成像生物标志物，并计算相关系数（r）和决定系数（R）。
与对照组（n = 10）相比，超重组（n = 9）的平均内脏脂肪体积（1843 vs 329 cm，P < 0.001）和皮下脂肪体积（7663 vs 893 cm，P < 0.001）更大，内脏脂肪PDFF（80% vs 45%，p < 0.001）和皮下脂肪PDFF（89% vs 75%，P = 0.003）也更高。内脏脂肪体积（r = 0.79，P < 0.001）和PDFF（r = 0.92，P < 0.001）与肝脏PDFF相关。在超重受试者中，内脏脂肪PDFF每增加一个单位，肝脏PDFF增加2.64%；内脏脂肪PDFF解释了肝脏PDFF变异的54%（R = 0.54，P = 0.02）。
在本研究中，我们使用自由呼吸MRI测量儿童的身体成分。未来需要进一步研究皮下和内脏脂肪PDFF的潜在价值，并验证自由呼吸MRI身体成分生物标志物。
