Correlation of diffusion-weighted MR imaging with cellularity of renal tumours.

BACKGROUND Diffusion is a physical process based on the random movement of water molecules known as Brownian movement. Diffusion-weighted imaging (DWI) is a magnetic resonance (MR) technique that provides information about the biophysical properties of tissues such cell organization and density, microstructure and microcirculation. MATERIALS AND METHODS Twenty healthy volunteers and 18 patients with renal tumor were enrolled in our study. The DWI was obtained before contrast media injection with a single-shot SE EPI Inversion Recovery (IR) sequence. The tumor cellularity of each resected lesion was evaluated. RESULTS The mean apparent diffusion coefficient (ADC) value of renal tumors was significantly lower than the mean ADC value of normal renal parenchyma. In our series, the mean ADC value of renal tumors did not significantly correlate with tumor cellularity, but correlated with histological architecture. CONCLUSION These preliminary results indicate the utility of DWI in the acquisition of tissue characterization data of renal masses using a minimal acquisition time (17 sec).