Real time ultrasound was performed just prior to the biopsy by a single investigator masked to the clinical diagnosis. The liver biopsy was reviewed by a pathologist masked to the clinical indication or sonographic findings.
Of 73 consecutive patients studied, macrovesicular steatosis of any severity on biopsy was found in 46 (63 % ) and micro vesicular fat found in 51 (69.9 % ). The overall impression of the sonographer for the presence of macrovesicular hepatic steatosis of any degree had a sensitivity of 60.9 % and a specificity of 100 % . The sensitivity increased to 100 % and the specificity to 90 % when there was 20 % of fat. The zonular distribution of the fat did not alter the diagnostic accuracy of ultrasound. Ultrasound had a poor yield in the diagnosis of microvesicular fat with an overall sensitivity of 43 % and a specificity of 73 % . The combination of increased echogenicity and portal vein blurring on ultrasound had the greatest sensitivity in the diagnosis of hepatic steatosis.
Real time ultrasound using a combination of sonographic findings has a high specificity but underestimates the prevalence of hepatic steatosis when there is < 20 % fat.