Published online Sep 27, 2020. doi: 10.4254/wjh.v12.i9.661
Peer-review started: June 4, 2020
First decision: June 20, 2020
Revised: June 29, 2020
Accepted: August 15, 2020
Article in press: August 15, 2020
Published online: September 27, 2020
Processing time: 108 Days and 19.2 Hours
Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, affecting up to 40% of the world population. It is characterized by fatty liver infiltration, and encompasses a wide clinical spectrum, ranging from a relatively benign isolated steatosis from potentially progressive nonalcoholic steatohepatitis (NASH), liver fibrosis and cirrhosis.
The diagnosis of NASH is crucial and has prognostic and therapeutic implications. Liver biopsy is currently the gold standard for diagnosing progressive NASH and has several limitations, such as sampling error, cost, and risk of complications.
Abundant research has been performed to develop noninvasive diagnostic methods for the early detection of NASH and its accurate differentiation from isolated steatosis, due to the utmost clinical importance of this diagnosis.
To evaluate the performance of gadoxetic acid–enhanced magnetic resonance imaging (GA-MRI) to differentiate NASH in patients with NAFLD using histopathology as the reference standard.
In this prospective study, 56 patients with NAFLD (18 with isolated steatosis and 38 with NASH) underwent GA-MRI. Contrast enhancement index (CEI) was calculated as the rate of increase of the liver-to-muscle signal intensity ratio before and 20 min after intravenous GA administration. Between-group differences in mean CEI were tested with the Student's t-test. Area under the receiver operator characteristic curve, and the diagnostic performance of GA-MRI were evaluated.
The mean CEI for all subjects was 1.82 ± 0.19. The mean CEI was significantly lower in patients with NASH than in those with isolated steatosis (P = 0.008). Two CEI cut-off points were used: < 1.66 (94% specificity) to characterize NASH and > 2.00 (89% sensitivity) to characterize isolated steatosis. CEI values between 1.66 and 2.00 indicated liver biopsy, and the procedure could be avoided in 40% of patients with NAFLD.
Patients with NASH have significantly lower CEIs in the hepatobiliary phase of GA-MRI than do patients with isolated steatosis. This study suggests that GA-MRI may be an effective noninvasive method for the identification of patients for whom early intervention and more aggressive therapy should be implemented, avoiding liver biopsy in up to 40% of the NAFLD population.
The possibility of using GA-MRI as a noninvasive and comprehensive diagnostic modality holds great promise. As it is a preliminary study, further prospective studies with a larger sample size are warranted.