title: Quantitative iodine content threshold for discrimination of renal cell carcinomas using rapid kV-switching dual-energy CT.
abstract: Determine iodine content threshold discriminating papillary renal cell carcinomas (pRCC) from complex cysts (CCs) using rapid kV-switching dual-energy CT (rsDECT).
  
  
  
  IRB-approved retrospective study of 72 consecutive patients with pathologic diagnosis of renal cell carcinoma, who underwent rsDECT from 2011 to 2015. Controls included consecutive patients with CC during same period. Iodine content of each pRCC (n = 27) was measured on rsDECT workstation for arterial (n = 15) or nephrographic phase (n = 12), and compared to iodine content for clear cell renal cell carcinomas (ccRCC, n = 46) and complex cysts (n = 54). An optimal iodine content threshold was estimated using logistic regressions and Youden's J based on maximum specificity and sensitivity.
  
  
  
  Iodine threshold of 1.28 mg/cc was optimal to discriminate between pRCCs and CCs for nephrographic phase (sens 1.0, spec 0.96, PPV 0.92, and NPV 1.0, AUC 0.997, acc 0.97, p < 0.0001). Iodine threshold of 1.22 mg/cc was the optimal cutoff value to discriminate between pRCCs and CCs in the arterial phase (sens 0.67, spec 0.97, PPV 0.91, NPV 0.85, AUC 0.76, and acc 0.84, p = 0.006). The optimal threshold to discriminate between ccRCCs and pRCCs was 1.85 mg/cc in the arterial phase (sens 0.87, spec 0.92, PPV 0.87, NPV 0.92, p < 0001) and 2.71 mg/cc in the nephrographic phase (sens 1.0, spec 1.0, PPV 1.0, NPV 1.0, p < 0.0001).
  
  
  
  Quantitative iodine values on rsDECT discriminate between papillary RCC and complex cysts, and between papillary RCC and clear cell RCC, the former addressing an important clinical challenge particularly when an unenhanced series has not been performed. These rsDECT thresholds differ from values derived from dual-source DECT technology.
authors.affiliation: Department of Radiology, University of Alabama at Birmingham, 619 19th Street South, JTN 357, Birmingham, AL, 35294, USA. jgzarzour@uabmc.edu.
authors.forename: Jessica G
authors.initials: JG
authors.lastname: Zarzour
authors.affiliation: Department of Radiology, University of Alabama at Birmingham, 619 19th Street South, JTN 357, Birmingham, AL, 35294, USA.
authors.forename: Desmin
authors.initials: D
authors.lastname: Milner
authors.affiliation: Department of Radiology, University of Alabama at Birmingham, 619 19th Street South, JTN 357, Birmingham, AL, 35294, USA.
authors.forename: Roberto
authors.initials: R
authors.lastname: Valentin
authors.affiliation: Department of Preventative Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Bradford E
authors.initials: BE
authors.lastname: Jackson
authors.affiliation: Department of Pathology, University of Alabama at Birmingham, Birmingham, AL, USA.|Department of Urology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Gordetsky
authors.affiliation: School of Medicine, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Janelle
authors.initials: J
authors.lastname: West
authors.affiliation: Department of Radiology, University of Alabama at Birmingham, 619 19th Street South, JTN 357, Birmingham, AL, 35294, USA.|Department of Urology, University of Alabama at Birmingham, Birmingham, AL, USA.
authors.forename: Soroush
authors.initials: S
authors.lastname: Rais-Bahrami
authors.affiliation: Department of Radiology, University of Alabama at Birmingham, 619 19th Street South, JTN 357, Birmingham, AL, 35294, USA.
authors.forename: Desiree E
authors.initials: DE
authors.lastname: Morgan
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002291:Carcinoma, Papillary / Q000000981:diagnostic imaging* / Q000473:pathology; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging* / Q000473:pathology; D003287:Contrast Media; D003560:Cysts / Q000000981:diagnostic imaging*; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D007472:Iohexol; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D060787:Neoplasm Grading; D011860:Radiography, Abdominal / Q000379:methods*; D015900:Radiography, Dual-Energy Scanned Projection / Q000379:methods*; D012680:Sensitivity and Specificity; D014057:Tomography, X-Ray Computed / Q000379:methods*
chemical_list: D003287:Contrast Media; D007472:Iohexol
keywords: Clear cell renal cell carcinoma; Complex cysts; Iodine quantification; Papillary renal cell carcinoma; Rapid switching dual energy CT