Positive Predictive Value of Ultrasound in Predicting Non-Alcoholic Fatty Liver Disease taking Magnetic Resonance Imaging as Gold Standard

Abstract

Objective: To determine the positive predictive value of ultrasound in predicting non-alcoholic fatty liver disease taking magnetic resonance imaging as gold standard.
Method: 84 patients of both sex groups with ages in the range of 18-60 years suspected to have NAFLD underwent ultrasound examination of the liver and kidney and the ratio of mean gray-scale intensity of the liver / renal cortex calculated. The NAFLD on ultrasound was labelled as per operational definition. The MRI was performed and areas under the water peak and fat peak were recorded. Liver fat content was calculated. The NAFLD on MRI waslabelled as per operational definition.All the data was noted along with demographic details of the patient.
Results: The age of the patients ranged from 18 years to 60 years with a mean of 41.4years. Male to female ratio of 1:5 was found. The BMI of the patients ranged from 22.6 Kg/m2 to 34.8 Kg/m2 with a mean of 30.8 Kg/m2 and 71.4% patients were obese. 34.5% patients were diabetic. The diagnosis of NAFLD was confirmed in 96.4% cases on MRI. Taking MRI diagnosis of NAFLD as gold standard, it yielded a positive predictive value of 96.4% for ultrasound in predicting NAFLD.
Conclusion: Ultrasound showed a high positive predictive value in the diagnosis of non-alcoholic fatty liver disease irrespective of patient's age, gender, BMI and history of diabetes which advocate its preferred use in  future medical practice.