title: Sigmoid cancer versus chronic diverticular disease: differentiating features at CT colonography.
abstract: OBJECTIVE
  To retrospectively identify morphologic findings at computed tomographic (CT) colonography that are the most reliable in the differentiation of masslike chronic diverticular disease from sigmoid carcinoma in a large patient cohort.
  
  
  METHODS
  This study was approved by the institutional review boards. The need for signed consent was waived for this retrospective study. The cohort consisted of 212 patients (mean age, 68 years; 113 women, 99 men) with focal masslike findings in the sigmoid colon at CT colonography, representing chronic diverticular disease (n = 97) or sigmoid carcinoma (n = 115). CT colonography studies were scored according to presence or absence of potential discriminators by a panel of four readers in consensus. Sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy were calculated, and multivariate analysis was performed.
  
  
  RESULTS
  Absence of diverticula in the affected segment showed high NPV and PPV (0.95 and 0.93, respectively). Also, shoulder phenomenon showed a high NPV (0.92) and PPV (0.75). Segment length of 10 cm or less (NPV, 0.85; PPV, 0.61) and destroyed mucosal folds (NPV, 1.00; PPV, 0.62) had a high NPV but a low PPV. Although segments affected by carcinoma often showed straightened and eccentric growth patterns, no thick fascia sign, and more and larger local-regional lymph nodes (all P < .05), NPV was insufficient for discrimination (NPV ≤ 0.66). Combination of absence of diverticula and presence of shouldering showed a high diagnostic certainty (93%).
  
  
  CONCLUSIONS
  Carcinoma is best differentiated from masslike diverticular disease by the absence of diverticula in the affected segment and the presence of shoulder phenomenon.
authors.affiliation: From the Departments of Radiology (L.M.J.L., M.T.d.W., P.C.G.S.) and Clinical Epidemiology (M.L.G.J.), VieCuri Medical Centre, Tegelseweg 210, 5912 BL Venlo, the Netherlands; Department of Radiology, Maxima Medical Centre, Veldhoven, the Netherlands (P.T.J.C.); Department of Radiology, University of Wisconsin School of Medicine and Public Health, Madison, Wis (P.J.P.); and Department of Radiology, Albert Schweitzer Hospital, Dordrecht, the Netherlands (S.E.H.C.).
authors.forename: Leonie M J
authors.initials: LM
authors.lastname: Lips
authors.forename: Pierre T J
authors.initials: PT
authors.lastname: Cremers
authors.forename: Perry J
authors.initials: PJ
authors.lastname: Pickhardt
authors.forename: Simone E H
authors.initials: SE
authors.lastname: Cremers
authors.forename: Maryska L G
authors.initials: ML
authors.lastname: Janssen-Heijnen
authors.forename: Marcel T
authors.initials: MT
authors.lastname: de Witte
authors.forename: Petra C G
authors.initials: PC
authors.lastname: Simons
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D023881:Colonography, Computed Tomographic / Q000379:methods*; D003937:Diagnosis, Differential; D004239:Diverticulitis, Colonic / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D012811:Sigmoid Neoplasms / Q000000981:diagnostic imaging*