title: Quantitative assessment of solid renal masses by contrast-enhanced ultrasound with time-intensity curves: how we do it.
abstract: OBJECTIVE
  To discuss the evaluation of the enhancement curve over time of the major renal cell carcinoma (RCC) subtypes, oncocytoma, and lipid-poor angiomyolipoma, to aid in the preoperative differentiation of these entities. Differentiation of these lesions is important, given the different prognoses of the subtypes, as well as the desire to avoid resecting benign lesions.
  
  
  METHODS
  We discuss findings from CT, MR, and US, but with a special emphasis on contrast-enhanced ultrasound (CEUS). CEUS technique is described, as well as time-intensity curve analysis.
  
  
  RESULTS
  Examples of each of the major RCC subtypes (clear cell, papillary, and chromophobe) are shown, as well as examples of oncocytoma and lipid-poor angiomyolipoma. For each lesion, the time-intensity curve of enhancement on CEUS is reviewed, and correlated with the enhancement curve over time reported for multiphase CT and MR.
  
  
  CONCLUSIONS
  Preoperative differentiation of the most common solid renal masses is important, and the time-intensity curves of these lesions show some distinguishing features that can aid in this differentiation. The use of CEUS is increasing, and as a modality it is especially well suited to the evaluation of the time-intensity curve.
authors.affiliation: Department of Radiology, Keck USC School of Medicine, 1500 San Pablo St, 2nd Floor Imaging, Los Angeles, CA, 90033, USA. kevingeorgeking@gmail.com.
authors.forename: Kevin G
authors.initials: KG
authors.lastname: King
authors.affiliation: Department of Radiology, Keck USC School of Medicine, 1500 San Pablo St, 2nd Floor Imaging, Los Angeles, CA, 90033, USA.
authors.forename: Mittul
authors.initials: M
authors.lastname: Gulati
authors.affiliation: Department of Radiology, Keck USC School of Medicine, 1500 San Pablo St, 2nd Floor Imaging, Los Angeles, CA, 90033, USA.
authors.forename: Harshawn
authors.initials: H
authors.lastname: Malhi
authors.affiliation: Department of Radiology, Keck USC School of Medicine, 1500 San Pablo St, 2nd Floor Imaging, Los Angeles, CA, 90033, USA.
authors.forename: Darryl
authors.initials: D
authors.lastname: Hwang
authors.affiliation: Department of Urology, Keck USC School of Medicine, 1500 San Pablo St, Los Angeles, CA, 90033, USA.
authors.forename: Inderbir S
authors.initials: IS
authors.lastname: Gill
authors.affiliation: Department of Radiology, Keck USC School of Medicine, 1500 San Pablo St, 2nd Floor Imaging, Los Angeles, CA, 90033, USA.
authors.forename: Phillip M
authors.initials: PM
authors.lastname: Cheng
authors.affiliation: Department of Radiology, Keck USC School of Medicine, 1500 San Pablo St, 2nd Floor Imaging, Los Angeles, CA, 90033, USA.
authors.forename: Edward G
authors.initials: EG
authors.lastname: Grant
authors.affiliation: Department of Radiology, Keck USC School of Medicine, 1500 San Pablo St, 2nd Floor Imaging, Los Angeles, CA, 90033, USA.
authors.forename: Vinay A
authors.initials: VA
authors.lastname: Duddalwar
mesh_terms: D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging*; D003287:Contrast Media; D003937:Diagnosis, Differential; D006801:Humans; D007089:Image Enhancement; D007668:Kidney / Q000000981:diagnostic imaging / Q000473:pathology; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging*; D008279:Magnetic Resonance Imaging; D014057:Tomography, X-Ray Computed; D014463:Ultrasonography
chemical_list: D003287:Contrast Media
keywords: Angiomyolipoma; Contrast-enhanced ultrasound; Oncocytoma; Renal cell carcinoma; Renal mass; Time–intensity curve