Poster session 4: Benign and Malignant renal diseases and Kidney transplant| Volume 8, ISSUE 8, P677-678, September 2009

C59 Image fractal analysis in retroperitoneal fibrosis – 5 years of experience with 19 patients

      Introduction and Objectives

      To evaluate effective prognostic factors in the evolution of patients with retroperitoneal fibrosis and to establish the validity of fractal analysis in determining the disease severity in these patients.

      Material and Methods

      The study included 19 pts (M/F: 5/14) with a median age of 56, 4 yrs treated for idiopathic retroperitoneal fibrosis and bilateral obstructive renal failure between Jan 2004-Dec 2008. The data were evaluated about medical history, physical examination findings, laboratory tests, imaging methods (abdominal CT-scan, MRI), surgical treatment performed. All the patients had ureterolysis and omental wrapping. Parameters assessed on helical CT were: fibrosis width, interureteric distance, maximal cranio-caudal length in sagital section and fibrosis surface area – using fractal analysis. The patients were followed up postoperatively at 3 and 6 mts. Assessment of renal function was based on the clearance of creatinine and helical CT scan at 6 mts. Positive outcome was considered an increase of clearance of creatinine and a decrease of hydronephrosis level.


      All patients had at admission high BUN levels, with a median creatinine level 10.2 (range 6.5–18.7 mg/dl), median clearance of creatinine = 27 mL/min/1.73 m2. They were initially stented (17-bilateral/2-unilateral), but after 2 days, 16(84.2%) underwent bilateral nephrostomy for further decreasing of BUN levels or for oligoanuria. Preoperative median serum creatinine was 2.3 (range 3.7–1) median clearance of creatinine=70 mL/min/1.73 m2. Median imaging parameters preop. were: 3.8 cm (range 6–2.2 cm) fibrosis width, interureteric distance at intervertebral discus L4-L5= 6.8 cm (range 5.6–9.2 cm), fractal dimension of the fibrosis surface area=1,67788, maximal cranio-caudal length in sagital section 10.8 cm (range: 7.9–13.4 cm). Postoperative, at 3 mts, the median clearance of creatinine had an increase of 10% (range:60–80 mL/min/1.73 m2) and at 6 mts the median clearance of creatinine had an increase of 21% (range:75–98 mL/min/1.73 m2). 6 of 19 pts had a stable GFR rate, with a median clearance of creatinine of 73 mL/min/1.73 m2. Except for the increase in fractal dimension of the fibrosis surface area, no significant differences were found between the improvement of renal function and metabolic and imaging parameters. An increase in fractal dimension expressed by greater complexity may correlate with a lower increase of the clearance of creatinine.


      The imaging parameters did not predict the disease severity, except the increase in fractal dimension of fibrosis surface area. Efficacy of bilateral ureteric stenting in improving renal function is limited in most cases. Metabolic parameters and predisposing factors and extent of the disease seemed to be important risk factors for predicting retroperitoneal fibrosis severity.