Sonographic quantification of a hepato-renal index for the assessment of hepatic steatosis in comparison with 3T proton magnetic resonance spectroscopy.
BACKGROUND
Nonalcoholic fatty liver disease is the most frequent hepatic disorder in the developed world. Currently, liver biopsy and proton magnetic resonance spectroscopy (H-MRS) are considered the gold standard methods for the quantification of liver fat deposits.


OBJECTIVE
To determine whether a Sonographic Hepato-Renal Index (SHRI) calculated using a standard workstation, without a specifically designed software, is an adequate alternative to H-MRS for the quantification of fat liver content and diagnosis of steatosis in the general population.


METHODS
A total of 121 volunteers (mean age=46 years, range=21-77 years) were recruited at three medical centers in Granada (Southern Spain) from among individuals attending routine general checkups. All participants were examined by ultrasound and by H-MRS 3T, which served as a reference for the diagnosis of steatosis. The SHRI was calculated as the ratio between the echogenicity of the liver and that of the right renal parenchyma. The validity of the methodology was assessed by receiver operating characteristic curves and correlation tests.


RESULTS
The quantitative SHRI showed a strong correlation (Spearman's coefficient=0.89, P<0.001) with the H-MRS 3T. The optimal SHRI cutoff points of 1.21, 1.28, and 2.15 yielded 100% sensitivity for the diagnoses of steatosis greater than 5, 25, and 50%, respectively, with a specificity greater than 70%.


CONCLUSIONS
This study shows that the SHRI is a valid, simple, reliable, and cost-effective screening tool for the identification, assessment, and quantification of hepatic steatosis in the general population.
aDepartment of Radiology, San Cecilio University Hospital bLaboratory of Medical Investigations, San Cecilio University Hospital, University of Granada Departments of cPreventive Medicine and Public Health dMedicine, School of Medicine University of Granada eConsortium for Biomedical Research in Epidemiology and Public Health, Granada, Spain.
José L
JL
Martín-Rodríguez
Juan P
JP
Arrebola
José J
JJ
Jiménez-Moleón
Nicolás
N
Olea
Jorge L
JL
González-Calvin
D050154:Adiposity; D000328:Adult; D000368:Aged; D019540:Area Under Curve; D005234:Fatty Liver / Q000175:diagnosis* / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D007090:Image Interpretation, Computer-Assisted; D007668:Kidney / Q000648:ultrastructure*; D008099:Liver / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008875:Middle Aged; D065626:Non-alcoholic Fatty Liver Disease; D011237:Predictive Value of Tests; D012372:ROC Curve; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013030:Spain; D014463:Ultrasonography; D055815:Young Adult