CT guided percutaneous renal biopsy versus ultrasound guided for obtaining adequate tissue.

OBJECTIVE To study the diagnostic yield of specimen obtained by percutaneous renal biopsy (PRB) under CT guidance and Ultrasound (US) guidance. METHODS This study was conducted at the department of Nephrology at Liaquat National Hospital and Dr. Ziauddin Hospital, Karachi. Renal biopsy specimens obtained between January 2007 and September 2009 were studied for number of glomeruli obtained. In addition data was collected of how many patients had to undergo renal biopsy again because of nonavailability of renal cortex (the area of the kidney that contains glomeruli necessary for diagnosing renal disease) by both methods. RESULTS We analyzed 205 renal biopsy specimens. Fifty were obtained via CT and 155 under US guidance. All 50 specimens obtained by CT guidance had renal cortex, compared to 147/155 (94.8%) specimen obtained by US guidance. Mean number of glomeruli in US guided specimens was 10.28 +/- 6.85, compared to CT guided specimen which was 23.34 +/- 13.42. Definitive diagnosis was made in 100% of CT guided biopsy compared to 94.8% (p<0.001) in US guided specimens. None of the patients undergoing CT guided biopsy required re-biopsy. CONCLUSION PRB of native kidney under CT guidance is a more effective tool compared to ultrasound guidance in obtaining renal cortex that prevents patients from undergoing biopsy twice and provides sufficient number of glomeruli for definitive diagnosis of renal diseases especially when focal disease is suspected.