Published online Mar 28, 2019. doi: 10.3748/wjg.v25.i12.1513
Peer-review started: December 21, 2018
First decision: January 18, 2019
Revised: January 29, 2019
Accepted: February 22, 2019
Article in press: February 23, 2019
Published online: March 28, 2019
Nonalcoholic fatty liver disease (NAFLD) is a common cause of chronic liver disease in children and adolescents. Many methods are used to diagnose NAFLD, including liver biopsy, ultrasonography (US), computed tomography (CT), magnetic resonance imaging (MRI), and magnetic resonance spectroscopy (MRS). Liver biopsy is the gold standard to diagnose NAFLD but invasive, which is not the best choice in clinical use. Hence, screening for a noninvasive and accurate method to diagnose NAFLD in Chinese children and adolescents is of great importance.
MR is widely used in clinical trials to detect hepatic steatosis. Compared with US and CT, MR can provide more accurate and reliable diagnosis information. Besides, it can be used in early diagnosis and follow-up of NAFLD. Unfortunately, limited by samples and software device, it is rarely used in Chinese children and adolescents.
To investigate the accuracy and agreement between MRI and MRS in estimation of hepatic proton density fat fraction in Chinese children and adolescents, which will be helpful to early diagnosis and follow-up of NAFLD in China.
Eighty-six children and adolescents were enrolled in this study (mean age 13.6 ± 1.9 years, range 9-17 years) from Shenzhen, China. They underwent MRI and MRS scans with a 3 Tesla MR unit (MAGNETOM Skyra, Siemens Healthcare, Erlangen, Germany). MRI and MRS were performed with multi-echo Dixon (ME Dixon) and HISTO sequences, respectively, to calculate hepatic proton density fat fraction (PDFF). Hepatic steatosis was defined as MRS-PDFF > 5%. The correlation and agreement between ME Dixon and MRS were assessed via spearman’s analysis and Bland-Altman analysis, respectively. According to the liver classification results of MRS-PDFF, the sensitivity, specificity, positive predictive value, and negative predictive value were calculated to assess the diagnostic accuracy of MRI-PDFF.
PDFF of all participants were calculated via MRI and MRS. With MRS as a reference, MRI exhibited high accuracy (r > 0.9, P < 0.01) and consistency in estimation of liver fat content. More importantly, MRI can quantify hepatic steatosis not only in region of interest but also the entire liver. Due to ethical restrictions, liver biopsy was not performed on our relatively healthy participants. Further study is needed to validate the accuracy of MRI and MRS in the quantification of hepatic steatosis in Chinese children and adolescents, with histology as a reference.
According to our study, MRI (ME Dixon) appears to detect hepatic steatosis in Chinese children and adolescents successfully and accurately, with MRS (HISTO sequences) as a reference. MRI (ME Dixon) may be an ideal tool for early diagnosis and follow-up of NAFLD in China.
This study describes a noninvasive tool for diagnosing NAFLD in Chinese children and adolescents. This method could be widely used in detecting hepatic steatosis in China, especially for those who have risk factors of NAFLD. Of course, liver biopsy and large sample sizes are needed in further study.