Frequency of abnormalities detected by abdominal ultrasound among Japanese adults.

Abdominal ultrasound examination was given to 715 (566 male and 149 female) adult non-manual workers in Tokyo as part of their annually required medical check-up. Gross abnormalities were found in 44.5% of males and 34.2% of females. The most common finding was fatty liver (15.2%), seen four times as frequently in males as in females. There were 93 elevated lesions in the gall-bladder in 56 subjects (7.8%); some required follow-up examinations because malignancy could not be excluded. Small cystic lesions were frequently seen in the kidney (6.4%) and in the liver (4.8%). Gallstones were found in 3.4%. Mild splenomegaly occurred in 3.4%. Ten mass lesions, 8 hyperechoic and 2 hypo-echoic, were found in the liver, but subsequent imaging studies showed them to be benign haemangiomas. Other changes found included calcific lesions in the liver (2.1%) and in the spleen (0.4%), renal stones (2.0%), thickened wall of the gall-bladder (3.2%), intramural stones (0.8%) and debris/sludge (0.4%) in the gall-bladder, dilated pancreatic duct (0.7%) and common bile duct (0.3%), liver cirrhosis (0.4%), hydronephrosis (0.1%), enlarged pancreas (0.1%), small pancreas (0.1%), ovarian tumour (0.1%), uterine tumour (0.1%), abnormally shaped kidney (0.1%) and situs inversus (0.1%). It was concluded that abdominal ultrasound is an important examination for a mass screening or a physical check-up commonly practised as the 'human dock' for adults in Japan.