Added value of CT colonography after a positive conventional colonoscopy: impact on treatment strategy P. P. Mainenti, 1,2 M. Romano, 1,2 M. Imbriaco, 1,2 L. Camera, 2 L. Pace, 2 D. D’Antonio, 3 L. Bucci, 3 G. Galloro, 3 M. Salvatore 2 1 IBB CNR, Naples, Italy 2 Department of Biomorphological and Functional Sciences, University Federico II, Via Pansini, 5, 80131 Naples, Italy 3 Department of Surgery and Endoscopy, University Federico II, Via Pansini, 5, 80131 Naples, Italy Abstract Background: Conventionalcolonoscopy(CC)requiresan experienced operator to avoid technical or interpretative errors, and an endoscopic error rate of 14% for tumor localization has been reported. We evaluated the impact of computed tomographic colonography (CTC) on sur- gical treatment strategy in patients with CC reported as having colorectal neoplasm. Methods: Fifty-three patients testing positive for colo- rectal neoplasm on CC underwent CTC: 32 patients had CC in our hospital (group A) and 21 had CC in area hospitals (group B). All CTC procedures were per- formed with a multidetector CT system. The results of CTC and CC were compared with that of surgery. The preoperative surgical planning evaluated on the basis of CC and CTC was compared with the actual surgical approach, and the percentage of patients in whom CTC modified the treatment strategy suggested by CC was calculated. Results: CTC changed the treatment strategy in four of 53 patients (7.5%) in whom CC showed technical or interpretative errors. Group analysis showed that CTC did not influence the surgical management in any pa- tient in group A but did affect treatment strategy in four of 21 patients (19%) in group B. The effect of CTC on treatment strategy between groups was statistically sig- nificant (p<0.05). CTC identified five adenomas and three adenocarcinomas localized proximally to an im- passable stenosis. Conclusion: CTC can be used to reevaluate the findings of a positive CC and can indicate a more correct ther- apeutic approach in patients with colorectal neoplasms who are candidates for surgery. Key words: Computed tomographic colonography —Colonoscopy—Neoplasm—Treatment strategy Although conventional colonoscopy (CC) represents the most accurate examination for colonic mucosa, 10% to 20% of colonic polyps and 5% of all colorectal cancers may be missed [1–4]. CC requires an experienced oper- ator to avoid technical or interpretative errors [1–4], and an endoscopic error rate of 14% for tumor localization has been reported [5]. Moreover, failure to visualize the entire colonic surface has been reported to occur in 5% to 10% of all CC examinations [6], and 40% to 58% of CC examinations have been positive for colon cancer [7– 9]. Computed tomographic colonography (CTC) is a safe and noninvasive technique and an accurate method for detecting cancers [10] and polyps 10 mm or larger in diameter, with a sensitivity of 75% to 100% and a spec- ificity of 82% to 100% per patient [11]. Variable results have been reported for the detection of polyps of 6 to 9 mm, with a sensitivity of 22% to 82% [11]. The role of CTC as a feasible and useful method for the evaluation of the entire colon in patients with neo- plastic stenosis on CC recently has been established [12, 13]; however, considering the general risk for errors associated with CC, all positive results on CC, complete or incomplete, can be confirmed when combined with CTC. The surgical approach for colon cancer, such as site andsizeofincision,extentofresection,andstomasite,is based on the number, location, and size of lesions. The Correspondence to: P. P. Mainenti, Corso Vittorio Emanuele, 670, 80122 Naples, Italy; email: pierpamainenti@hotmail.com ª Springer Science+Business Media, Inc. 2004 Received: 12 November 2003 / Revision accepted: 28 January 2004 / Published online: 17 November 2004 Abdominal Imaging Abdom Imaging (2005) 30:42–47 DOI: 10.1007/s00261-004-0246-8