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New radiologic classification of renal angiomyolipoma: frequently asked questions

  • Sung Goo Park
    Affiliations
    Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
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  • Byung Kwan Park
    Correspondence
    Corresponding author at: Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, 81 Irwon-ro, Gangnam-ku, Seoul 06351, Republic of Korea.
    Affiliations
    Department of Radiology, Samsung Medical Center, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
    Search for articles by this author
Published:February 01, 2019DOI:https://doi.org/10.1016/j.clinimag.2019.01.025

      Highlights

      • Song classification provides quantitative CT and MRI criteria for renal angiomyolipoma (AML).
      • Renal AMLs can be fully classified into three subtypes with Song classification.
      • Generally, biopsy is not recommended for fat-rich AML, but for fat-invisible AML.
      • Biopsy should be considered for fat-poor AML which MRI findings are indeterminate.
      • Song classification contributes to terminology standardization and to inter-researcher communication.

      Abstract

      Recently, a new classification of renal angiomyolipoma (AML) has been introduced to clinical practice. This classification categorizes AMLs into three subtypes (fat-rich, fat-poor, and fat-invisible AMLs) based on quantitative CT and MRI criteria. Radiologists who get used to previous AML classification may have questions about how to apply a new classification. The purpose of this review is to answer the questions that are frequently asked about the new AML classification.

      Abbreviations:

      AML (Angiomyolipoma), RCC (Renal cell carcinoma), CT (Computed tomography), MRI (Magnetic resonance imaging), ROI (Region of interest), TSR (Tumor to spleen ratio), SII (Signal intensity index)

      Keywords

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