Differentiating Renal Cell Carcinoma and Minimal Fat Angiomyolipoma with Volumetric MRI Histogram Analysis

Objective: In this study, the utility of histogram parameters derived from diffusion-weighted imaging to differentiate renal cell carcinoma (RCC) from renal minimal fat angiomyolipoma (MFAML) was investigated. Methods: In this retrospective study, 98 patients who were histopathologically diagnosed with RCC and MFAML and who underwent magnetic resonance imaging (MRI) examinations between 2015 and 2022 were included. Demographic data, preoperative MRI findings, MRI apparent diffusion coefficient (ADC) histogram analyses, operation types, and postoperative histopathological data of the patients were recorded. The mean, minimum (min), maximum (max), 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles as well as skewness, kurtosis, and variance of ADC values were calculated. Results: The study included 61 males and 37 females. Eighty eight of the patients had RCC and 10 had AML. In terms of age and gender, there was no significant difference between the two groups. The AML group's ADCmin, ADCmedian, ADCmean, ADCmax, 5th, 10th, 25th, 50th, 75th, 90th, and 95th percentiles were all lower than those of the RCC group. ADCmax value (p<0.001), as well as ADCmedian and the 50th, 75th, 90th, and 95th percentiles of ADC values (p<0.05), demonstrated a statistically significant difference. However, there was no statistical significance between ADCmin, ADCmean, and the 5th, 10th, and 25th percentiles of ADC values (p>0.05). The area under the curve, sensitivity, and specificity of the ADCmax value were 0.795, 62.4%, and 88.9%, respectively. Conclusion: A whole tumor histogram and textural analysis of ADC values could be useful in distinguishing MFAML from RCC.