Small (<1 cm) incidental echogenic renal cortical nodules: chemical shift MRI outperforms CT for confirmatory diagnosis of angiomyolipoma (AML)

Non-calcified echogenic renal cortical nodules are commonly detected with abdominal ultrasound (US). The majority of these nodules represent benign angiomyolipomas (AMLs), which are present in 0.3–2.1 % of the population at autopsy [1]. The increased echogenicity (in the absence of calcification) of renal AML is due to the presence of gross or mature fat within the nodule [2]. Although renal AMLs are typically markedly echogenic, echogenicity may vary depending upon therelativeproportionoffat,smoothmuscleandbloodvessels