Differentiation of malignant and benign kidney and bladder masses with diffusion weighted magnetic resonance imaging

SUMMARYIn this study, a total of 36 mass cases including 12 urinary bladder and 24 kidneywere studied regarding ADC values.Mass ADC values of 12 cases (ages of 52-82) with bladder mass were compared tonormal bladder wall ADC values. There were 11 male and one female cases. Histopathologyof 11 cases were carcinoma and there was a correlation between ADC values and thepathology. Average ADC values of these masses (1,098 x10-3 mm2/s) were significantly lowerthan those of normal bladder wall (1,979 x10-3 mm2/s) (p<0.0001). A benign pathologydiagnosed only in one of these cases. This case was a 63 years old male with diffuse bladderwall thickening secondary to prostate hypertrophy. ADC value of the region with local wallthickening was 2.10x10-3 mm2/s and significantly higher than ADC value of malignantmasses. Our results show that, DWI may be valuable in distinguishing malignant from benignurinary bladder masses.The kidney mass group included 24 cases (ages 6-80, 16 male and 8 female). Ofthese masses 17 were malignant (10 renal cell carcinoma, 2 cysctic nephroma, 1 Wilm?stumor, 1 transitional cell carcinoma, 2 nonhodking lymphoma, 1 neuroblastoma), and 7 werebenign (2 angiomyolipoma, 2 simple cysts, 2 kidney abscesses, 1 Bertini columnarhypertrophy) clinicopathologically. Without malignant-benign classification, average ADCvalues of all masses were 1,385 x10-3 mm2/s and ADC values of normal kidney parenchymawere found to be 2.096 x10-3 mm2/s. ADC values of malignant masses (1.005x10-3 mm2/s)were significantly lower than those of normal kidney parenchyma (2.096x10-3mm2/s),(p<0.0001). ADC values of benign masses (2.245x10-3 mm2/s) were significantlyhigher than those of normal kidney parenchyma (2.096x10-3 mm2/s),(p<0.0001).In many of cases, pre-diagnosis of benign-malignant masses were correctly madewith other radiological imaging modalities in correlation with DWI. However, in a case withsuspicious mass, ADC values were similar to that of normal kidney parenchyma and Bertinicolumnar hypertrophy was diagnosed pathologically. When histopathology and ADC valuesof kidney masses were compared, lowest values were detected in nonhodking lymphoma andneuroblastoma cases and average ADC values of renal cell carcinomas were higher thanthese.Our results show that in differentiation of benign and malignant masses of kidney andbladder, DWI may be used safely.67