Ultrasound-guided renal biopsy: experience using an automated core biopsy system.

OBJECTIVE: To assess the safety and efficacy of ultrasound-guided percutaneous renal biopsy using an automated core biopsy system, and to determine radiologists' accuracy in predicting sample adequacy. METHODS: Ninety-five biopsies were performed on 25 native kidneys and 70 renal allografts using a 16-gauge automated, spring-loaded core biopsy device under real-time sonographic guidance. Radiologists performing the biopsy estimated the number of core samples needed to obtain an adequate specimen, based on visual inspection of each core. The final determination of the number of samples was made by a pathology technologist who attended each biopsy, based on preliminary microscopic examination of tissue cores. After each biopsy, an ultrasonographic examination was performed to search for biopsy-related hemorrhage, and a questionnaire was given to the patient to determine biopsy-related complications, which were categorized as either minor or major. RESULTS: The main indication for biopsy was acute renal failure (in 43.2% of biopsies). An average of 3 tissue cores per biopsy were obtained. Of the 94 patients in whom a biopsy was conducted to exclude diffuse renal disease, a mean of 12.5 glomeruli were present in each specimen. Overall, adequate tissue for diagnosis was obtained in 98.9% of cases. The radiologists' estimate of the number of core samples needed concurred with the pathology technologists' determination of sample adequacy in 88.4% of cases. A total of 26 complications occurred (in 27.4% of biopsies), consisting of 23 minor (24.2%) and 3 major (3.2%) complications. CONCLUSIONS: Real-time sonographic guidance in conjunction with an automated core biopsy system is a safe and accurate method of performing percutaneous renal biopsy. Routine use of sonographic examinations to search for biopsy-related complications is not indicated. Radiologists are accurate in estimating sample adequacy in most cases; however, the presence of a pathology technologist at the biopsy procedure virtually eliminates the possibility of obtaining insufficient tissue for histologic diagnosis.