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 CTguidance 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 werestudied for number of glomeruli obtained. In addition data was collected of how many patients had to undergorenal biopsy again because of nonavailability of renal cortex (the area of the kidney that contains glomerulinecessary 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 obtainedby US guidance. Mean number of glomeruli in US guided specimens was 10.28 ± 6.85, compared to CTguided specimen which was 23.34 ± 13.42 .Definitive diagnosis was made in 100% of CT guided biopsycompared to 94.8% (p 0.001) in US guided specimens. None of the patients undergoing CT guided biopsyrequired re-biopsy.Conclusion: PRB of native kidney under CT guidance is a more effective tool compared to ultrasound guidancein obtaining renal cortex that prevents patients from undergoing biopsy twice and provides sufficient number ofglomeruli for definitive diagnosis of renal diseases especially when focal disease is suspected.