Eighty percent of patients with tuberous sclerosis complex (TSC) have renal angiomyolipomata. These lesions grow and can lead to significant morbidity by hemorrhage or renal failure. Understanding the natural history of these lesions and understanding which lesions may be more prone to grow quickly or develop aneurysms that predispose to hemorrhage will greatly assist clinical care of patients with TSC. The objective is to test the hypothesis that serial MR and CT imaging will allow objective, reproducible quantification of angiomyolipoma growth by volumetric analysis, and analysis of lesions characteristics will identify angiomyolipomata with rapid growth potential that would require intervention. The specific aim of this proposal is to collect clinically obtained serial abdominal imaging from the Tuberous Sclerosis Natural History Consortium Centers and analyze the volume and adiposity of the individual angiomyolipomata. The growth rate is hypothesized to have an inverse relationship to adiposity. Yearly renal MR or CT imaging will be performed of patients with TSC. The images will be coded at the site of acquisition, and transferred via VPN to a secure server at Cincinnati Children's Hospital Medical Center. Using innovative imaging processing software (Cincinnati Children's Hospital Image Processing Software (CCHIPS), the image data will be segmented to reveal various tissue components based on signal intensities. Different signal intensities can differentiate normal renal parenchyma, and renal angiomyolipomata. Using the imaging data and the novel software, the volume of an individual angiomyolipoma, as well as the adiposity will be determined. Imaging at enrollment (year 1) will serve as baseline. At years two and three, the lesions will undergo repeat analysis. Angiomyolipoma growth rates and adiposity over three years will be analyzed to test the hypothesis above.