Multiparametric Magnetic Resonance Imaging in Diagnosis of Small Renal Mass: A Medical Center Experience In Taiwan

Abstract PurposeMany studies have shown that multiparametric magnetic resonance imaging (MRI) may be helpful for differentiating malignant renal cell carcinomas (RCCs) from benign lesions. However, the key image characteristics between malignancy and benign tumors still require further discussion. MethodsWe gathered 60 adult patients diagnosed with 72 small renal masses (SRMs) who had received preoperative MRI from 2014 to 2019 at a hospital in Taiwan. The MRI features included conventional MRI parameter, diffusion weighted image (DWI), and dynamic contrast enhanced (DCE) pattern, which are documented and compared among the four common subtype groups: clear cell RCC(ccRCC), papillary RCC(pRCC), angiomyolipoma(AML) and other type RCC. An apparent diffusion coefficient (ADC) value of high and low grade RCCs was also analyzed. ResultsThe results show that ccRCC had higher T2 weighted signal intensity than the other three subgroups, higher arterial wash-in index (AWI) and ADC value than AML and pRCC, and also manifested a plateau (n=9, 25%) or washout (n=27, 75%) dynamic pattern. AMLs exhibited more intravoxel fat than the other three subtypes groups and half of AMLs (6 in 12) contained bulk fat. The pRCC demonstrated a more progressive (n=3, 60%) dynamic pattern than other three subgroups. The ADC value of high-grade RCCs was significantly lower than the low-grade RCCs.ConclusionThis may indicate that multiparametric MRI is useful in differentiating those four common pathological types of SRMs and the ADC value may be helpful in evaluation of the histological grade of malignancy.