Impact of sequential proton density fat fraction for quantification of hepatic steatosis in nonalcoholic fatty liver disease.
OBJECTIVE
To determine the utility of sequential MRI-estimated proton density fat fraction (MRI-PDFF) for quantification of the longitudinal changes in liver fat content in individuals with nonalcoholic fatty liver disease (NAFLD).


METHODS
A total of 18 consecutive individuals (M/F: 10/8, mean age: 47.7±9.8 years) diagnosed with NAFLD, who underwent sequential PDFF calculations for the quantification of hepatic steatosis at two different time points, were included in the study. All patients underwent T1-independent volumetric multi-echo gradient-echo imaging with T2* correction and spectral fat modeling.


RESULTS
A close correlation for quantification of hepatic steatosis between the initial MRI-PDFF and liver biopsy was observed (rs=0.758, p<0.001). The median interval between two sequential MRI-PDFF measurements was 184 days. From baseline to the end of the follow-up period, serum GGT level and homeostasis model assessment score were significantly improved (p=0.015, p=0.006, respectively), whereas BMI, serum AST, and ALT levels were slightly decreased. MRI-PDFFs were significantly improved (p=0.004). A good correlation between two sequential MRI-PDFF calculations was observed (rs=0.714, p=0.001). With linear regression analyses, only delta serum ALT levels had a significant effect on delta MRI-PDFF calculations (r2=38.6%, p=0.006). At least 5.9% improvement in MRI-PDFF is needed to achieve a normalized abnormal ALT level. The improvement of MRI-PDFF score was associated with the improvement of biochemical parameters in patients who had improvement in delta MRI-PDFF (p<0.05).


CONCLUSIONS
MRI-PDFF can be used for the quantification of the longitudinal changes of hepatic steatosis. The changes in serum ALT levels significantly reflected changes in MRI-PDFF in patients with NAFLD.
Liver Imaging Team, Hacettepe University, School of Medicine, Department of Radiology, Ankara University, Faculty of Medicine , Ankara , Turkey.
Ilkay S
IS
Idilman
Onur
O
Keskin
Atilla Halil
AH
Elhan
Ramazan
R
Idilman
Musturay
M
Karcaaltincaba
D050154:Adiposity; D000328:Adult; D000368:Aged; D000410:Alanine Transaminase / Q000097:blood; D001219:Aspartate Aminotransferases / Q000097:blood; D015992:Body Mass Index; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008103:Liver Cirrhosis / Q000097:blood / Q000175:diagnosis*; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease / Q000097:blood / Q000175:diagnosis* / Q000473:pathology; D011522:Protons; D013997:Time Factors; D005723:gamma-Glutamyltransferase / Q000097:blood
D011522:Protons; D005723:gamma-Glutamyltransferase; D001219:Aspartate Aminotransferases; D000410:Alanine Transaminase