title: Does Computed Tomography Still Have Limitations to Distinguish Benign from Malignant Renal Tumors for Radiologists?
abstract: OBJECTIVE
  To evaluate the current accuracy of CT for diagnosing benign renal tumors.
  
  
  METHODS
  We retrospectively reviewed 905 patients who underwent preoperative CT followed by surgical resection. The final pathology was benign in 156 patients (17%). After exclusions, 140 patients with 163 benign tumors were included and 3 sets of the CT interpretations by radiologists with varying levels of experience were analyzed.
  
  
  RESULTS
  The histological breakdown was as follows: oncocytomas (54.6%), angiomyolipomas (AMLs; 30.7%), renal cysts (8.0%), other miscellaneous benign tumors (6.7%). The sensitivities of diagnosing oncocytomas were 3.4, 9.0, and 13.5% in primary radiological reports, second blinded reviews, and third non-blinded reviews, respectively (p = 0.055). The sensitivities of diagnosing AMLs were 46.0, 58.0, and 62.0% in the 3-sets of CT interpretations, respectively (p = 0.246). As for renal cysts, the sensitivities were 69.2, 92.3, and 100% in the 3-sets of CT interpretations, respectively (p = 0.051). In primary reports, the positive predictive values were 95.8% in lipid poor (lp)-AMLs, 60.0% in oncocytomas, 69.2% in renal cysts, respectively (p < 0.05).
  
  
  CONCLUSIONS
  Current conventional CT imaging still has limitations in differentiating oncocytomas and lp-AMLs from renal cell carcinomas, even when images were re-examined by experienced radiologists.
authors.affiliation: USC Institute of Urology, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.
authors.forename: Toshitaka
authors.initials: T
authors.lastname: Shin
authors.forename: Vinay A
authors.initials: VA
authors.lastname: Duddalwar
authors.forename: Osamu
authors.initials: O
authors.lastname: Ukimura
authors.forename: Toru
authors.initials: T
authors.lastname: Matsugasumi
authors.forename: Frank
authors.initials: F
authors.lastname: Chen
authors.forename: Nariman
authors.initials: N
authors.lastname: Ahmadi
authors.forename: Andre Luis
authors.initials: AL
authors.lastname: de Castro Abreu
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Mimata
authors.forename: Inderbir S
authors.initials: IS
authors.lastname: Gill
mesh_terms: D018249:Adenoma, Oxyphilic / Q000000981:diagnostic imaging* / Q000473:pathology; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018207:Angiomyolipoma / Q000000981:diagnostic imaging* / Q000473:pathology; 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; D011237:Predictive Value of Tests; D000072177:Radiologists; D015203:Reproducibility of Results; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed; D055815:Young Adult
keywords: Angiomyolipoma; Benign tumor; CT; Oncocytoma; Renal tumor