title: Delayed computed tomographic characterization of renal masses: preliminary experience.
abstract: BACKGROUND
  To evaluate the performance of delayed contrast enhanced computed tomography (DCT) in characterizing renal masses.
  
  
  METHODS
  Twenty-four patients with suspected renal masses or indeterminate renal masses on previous imaging studies were prospectively evaluated with preintravenous contrast imaging, conventional contrast-enhanced computed tomography (imaging initiated 2 min after intravenous contrast injection), and DCT (imaging initiated 13 min after injection of intravenous contrast). Only lesions larger than 1.0 cm were evaluated, with scanning parameters kept constant across the three scans.
  
  
  RESULTS
  All pathologically confirmed renal cell carcinomas (n = 6) were detected on DCT using a threshold attenuation decrease of 10 Hounsfield units (HU). A significant decrease (p = 0.031) in attenuation occurred in renal cell carcinomas (mean = 29.6 +/- 23.6 HU) compared with the attenuation change (mean decrease = 1.1 +/- 7.1 HU), which occurred in non-neoplastic renal cysts (n = 34). Non-neoplastic renal cysts were correctly classified by DCT 32 of 34 times (94%).
  
  
  CONCLUSIONS
  In this study, DCT distinguished renal cell carcinomas from non-neoplastic cysts in a vast majority of cases and may aid in characterizing incidentally discovered renal lesions on postcontrast CT.
authors.affiliation: Department of Radiology, University of Rochester Medical Center, NY 14642, USA.
authors.forename: S L
authors.initials: SL
authors.lastname: Voci
authors.forename: R H
authors.initials: RH
authors.lastname: Gottlieb
authors.forename: P J
authors.initials: PJ
authors.lastname: Fultz
authors.forename: A
authors.initials: A
authors.lastname: Mehta
authors.forename: R
authors.initials: R
authors.lastname: Parthasarathy
authors.forename: D J
authors.initials: DJ
authors.lastname: Rubens
authors.forename: J G
authors.initials: JG
authors.lastname: Strang
mesh_terms: D000236:Adenoma / Q000000981:diagnostic imaging* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging* / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D052177:Kidney Diseases, Cystic / Q000000981:diagnostic imaging* / Q000473:pathology; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D014057:Tomography, X-Ray Computed