Cystic Renal Masses: characterization with Diffusion- Weighted Imaging Versus Contrast-Enhanced Magnetic Resonance Imaging

Abstract

Accurate assessment of cystic renal masses is important for establishing whether tumors require surgical intervention or not. CT and MRI are the primary investigative tools for characterizing of cystic renal mass utilizing up to date version of Bosniak classification system, however some studies have shown incompatible interobserver agreement in the Bosniak classification, at this point advanced diagnostic methods are needed in making precise judgments about cystic renal lesions. Diffusion-weighted imaging (DWI) is non-invasive MRI technique relies on the random motion of free water molecules and it has been widely used for the characterization of benign versus malignant processes in the abdomen without need for administration of contrast medium, Furthermore, DWI and it quantitative index {the apparent diffusion coefficient (ADC)} are now increasingly used for the evaluation of kidney tumors, including categorization and staging of solid renal tumors. In our study, we aimed to elucidate the additive imaging data obtained with diffusion-weighted magnetic imaging (DWI) and apparent diffusion coefficient (ADC) in characterizing of cystic renal masses, as well as comparing the diagnostic performance of DWI with that of contrast-enhanced MR imaging to make improvement on the diagnosis and differentiation of cystic renal masses through veracious MRI imaging techniques without exposing the patients to the risk contrast medium administration, especially in those patient with deranged renal function. In our study, a total of Sixty Three (63) adult patients underwent MRI (at 1.5 T), and DWI (at b-values of 0, 400 and 800 s/mm2) for characterization of 63 cystic renal lesions (one lesion per each patient). There were 16 malignant renal cystic lesions (9 cystic clear cell RCC, 4 cystic papillary RCC, 3 massively necrotic RCC) opposite to 37 benign renal cystic lesions, 6 renal abscesses and 4 renal hemorrhagic cysts. A composite reference standards including histology, typical imaging criteria, and follow-up imaging was employed.