title: Assessment of cystic renal masses based on Bosniak classification: comparison of CT and contrast-enhanced US.
abstract: OBJECTIVE
  To compare retrospectively the imaging features of computed tomography (CT) and contrast-enhanced US (CEUS) imaging for the assessment of cystic renal masses using the Bosniak classification system.
  
  
  METHODS
  The CT and CEUS images of 31 pathologically confirmed cystic renal masses in 31 patients were retrospectively analyzed for septa numbers, wall and/or septa thickness, enhancement degree, and for the presence of a solid component by consensus between two radiologists using the Bosniak classification. Diagnostic accuracies of CT and CEUS for malignant cystic tumor were calculated and compared using McNemar test.
  
  
  RESULTS
  Diagnostic accuracies of CT and CEUS for malignant renal tumor were 74% and 90%, respectively, but there were not statistically different (P>0.05). CEUS and CT images showed same Bosniak classification in 23 (74%) lesions and there were differences in 8 (26%) lesions, all of which were upgraded by CEUS; one lesion from I to IV, two lesions from II to IV, two lesions from IIF to III, and three lesions from III to IV. CEUS images depicted more septa in 10 (32%) lesions, more thickened wall and/or septa in 4 (13%) lesions, and stronger enhancement in 19 (61%) lesions. Moreover, for six lesions, solid component was detected by CEUS but not by CT.
  
  
  CONCLUSIONS
  CEUS might better visualize septa number, septa and/or wall thickness, solid component and the enhancement of some renal cystic masses than CT, resulting in upgrade of Bosniak classification and affecting their treatment plan.
authors.affiliation: The Department of Radiology and Center for Imaging Science, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Ilwon-dong, Kangnam-ku, Seoul, Republic of Korea. rapark@skku.edu
authors.forename: Byung Kwan
authors.initials: BK
authors.lastname: Park
authors.forename: Bohyun
authors.initials: B
authors.lastname: Kim
authors.forename: Seung Hyup
authors.initials: SH
authors.lastname: Kim
authors.forename: Kyungran
authors.initials: K
authors.lastname: Ko
authors.forename: Hyun Moo
authors.initials: HM
authors.lastname: Lee
authors.forename: Han Yong
authors.initials: HY
authors.lastname: Choi
mesh_terms: D000328:Adult; D000368:Aged; D002292:Carcinoma, Renal Cell / Q000000981:diagnostic imaging; D003287:Contrast Media; D003560:Cysts / Q000145:classification / Q000000981:diagnostic imaging*; D003951:Diagnostic Errors; D005260:Female; D006801:Humans; D007674:Kidney Diseases / Q000145:classification / Q000000981:diagnostic imaging*; D007680:Kidney Neoplasms / Q000000981:diagnostic imaging; D008297:Male; D008875:Middle Aged; D011859:Radiography; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D014463:Ultrasonography
chemical_list: D003287:Contrast Media