Current state and effectiveness of abdominal ultrasonography in complete medical screening

The current state and effectiveness of abdominal ultrasonography (US) were investigated by reviewing statistical data for US of the kidney as part of complete medical screenings conducted at our institution between April 1994 and March 2004.

Among 4339 individuals with US findings, computed tomography (CT) was performed on 129 individuals at our institution. Among these individuals, US findings and CT diagnoses were compared and analyzed.

US findings indicated renal tumors in 73 of the 129 subjects, and the breakdown of CT diagnoses for these 73 individuals was as follows: no lesion, n = 45 (61.6%); simple renal cyst, n = 13 (17.8%); complicated renal cyst, n = 5 (6.8%); suspected malignant tumor, n = 5 (6.8%); renal angiomyolipoma, n = 2 (2.7%); pelvic dilatation, n = 1 (1.4%); granuloma, n = 1 (1.4%); teratoma, n = 1 (1.4%). Magnetic resonance imaging (MRI) was performed on 4 of the 5 subjects with suspected malignant tumor, and surgery was performed in all 4 cases with suspected kidney cancer. Kidney cancer was histopathologically confirmed in 2 patients, resulting in a detection rate of 0.046% for kidney cancer by US as part of a complete medical screening. In the 2 patients with kidney cancer, differentiating cystic renal cell cancer from a renal cyst was not possible based on US findings alone in 1 patient, and no thorough examinations were performed in the 3 years leading up to surgery.

These results suggest that additional US and thorough examinations are necessary if a lesion cannot be confirmed as a simple renal cyst on initial US. Furthermore, to improve the skill levels of healthcare professionals who perform and interpret US, a feedback system should be established where data related to complete medical screenings are available to the personnel involved.