PURPOSE: We wished to compare CT colonography with conventional colonoscopy for the detection of colorectal polypoid lesions, and we wanted to evaluate the role of IV contrast-enhanced CT colonography for the differentiation between benign polypoid lesions and malignant polypoid lesions. MATERIALS AND METHODS: Thirty-four consecutive patients underwent CT colonography prior to conventional colonoscopy. Precontrast prone-position CT images and postcontrast supine position CT images were obtained and the virtual colonoscopic images were reconstructed. Axial, sagittal and coronal images with virtual colonoscopic images were prospectively interpreted for the presence, size and morphologic features of colorectal polypoid lesions, and then these findings were compared with the colonoscopic findings. The degree of enhancement of colorectal polypoid lesions was measured by subtracting the attenuation values obtained with precontrast and postcontrast CT images for the differentiation of benignity and malignancy of the colorectal polypoid lesions. RESULTS: Among 75 colorectal polypoid lesions identified on conventional colonoscopy, 49 neoplasms were found on CT colonography, and the overall detection rate was 65.3%. Detection rate of lesions smaller than 10 mm was 52.1% (24/46), and the detection rate for lesions equal to or larger than 10 mm was 86.2% (25/29). Morphologic features of the sessile type lesions on CT colonography were well correlated with those noted on colonoscopy, but the stalks were not identified in 6 of 13 polyps on CT colonography. There was no statistical correlation between benignity and malignancy and the degree of contrast enhancement on CT colonography. CONCLUSION: CT colonography is a useful modality for the detection of colorectal polypoid lesions equal to or larger than 10mm, and it well demonstrates the morphologic features, except for the stalk of pedunculated polyps. However, CT colonography cannot differentiate benignity from malignancy.
Colonography, Computed Tomographic* ; Colonoscopy ; Humans ; Polyps ; Prospective Studies ; Supine Position ; Tomography, X-Ray Computed

PURPOSE: The purpose of this study was to evaluate the diagnostic accuracy of CT and MR virtual colonoscopy using an experimental model of colonic polyposis. MATERIALS AND METHODS: Eleven pig colons ranging from 15 to 20cm in length were cleansed and a total of 99 variable sized polyps ranging from 3 to 15mm in diameter were created. The polyps were divided into three groups according to size: <5mm(n=23), 5-9mm(n=44), and ?10mm(n=32) in diameter. Each specimen was scanned using spiral CT and MRI. Each CT and MR virtual colonoscopy was independently evaluated by two radiologists blinded to the location, size and numbers of polyps, but aware that polyps were present. Interobserver agreement regarding the detection rate of the polyps during the two types of virtual colonoscopy was measured and the diagnostic accuracy of CT and MR virtual colonoscopy was compared. Results: In both CT and MR virtual colonoscopy, the detection rates determined by the two radiologists coincided in all three groups(p<0.05). The detection rates of polyps less than 5mm, between 5 and 9mm, and 10mm or larger in diameter were 74%(17/23), 89%(39/44), and 100%(32/32), respectively, in CT colonoscopy, and 61%(14/23), 89%(39/44), and 100%(32/32), respectively in MR colonoscopy. In polyps 5mm or larger, the results of the two types of virtual colonscopy coincided but in those less than 5mm in diameter, the results of MR virtual colonoscopy were slightly inferior to those of CT colonoscopy. Conclusion: Both CT and MR virtual colonoscopy provide high detection rates of colonic polyps 5mm or larger in diameter and these techniques can therefore be used to diagnose colonic mass lesions.
Colon ; Colonic Polyps ; Colonography, Computed Tomographic* ; Colonoscopy ; Magnetic Resonance Imaging ; Models, Theoretical ; Polyps* ; Tomography, Spiral Computed

PURPOSE: The purpose of this study was to evaluate the diagnostic accuracy of CT and MR virtual colonoscopy using an experimental model of colonic polyposis. MATERIALS AND METHODS: Eleven pig colons ranging from 15 to 20cm in length were cleansed and a total of 99 variable sized polyps ranging from 3 to 15mm in diameter were created. The polyps were divided into three groups according to size: <5mm(n=23), 5-9mm(n=44), and ?10mm(n=32) in diameter. Each specimen was scanned using spiral CT and MRI. Each CT and MR virtual colonoscopy was independently evaluated by two radiologists blinded to the location, size and numbers of polyps, but aware that polyps were present. Interobserver agreement regarding the detection rate of the polyps during the two types of virtual colonoscopy was measured and the diagnostic accuracy of CT and MR virtual colonoscopy was compared. Results: In both CT and MR virtual colonoscopy, the detection rates determined by the two radiologists coincided in all three groups(p<0.05). The detection rates of polyps less than 5mm, between 5 and 9mm, and 10mm or larger in diameter were 74%(17/23), 89%(39/44), and 100%(32/32), respectively, in CT colonoscopy, and 61%(14/23), 89%(39/44), and 100%(32/32), respectively in MR colonoscopy. In polyps 5mm or larger, the results of the two types of virtual colonscopy coincided but in those less than 5mm in diameter, the results of MR virtual colonoscopy were slightly inferior to those of CT colonoscopy. Conclusion: Both CT and MR virtual colonoscopy provide high detection rates of colonic polyps 5mm or larger in diameter and these techniques can therefore be used to diagnose colonic mass lesions.
Colon ; Colonic Polyps ; Colonography, Computed Tomographic* ; Colonoscopy ; Magnetic Resonance Imaging ; Models, Theoretical ; Polyps* ; Tomography, Spiral Computed

PURPOSE: To perform a frequency analysis of the extracolonic findings (ECF) of the CT colonography between symptomatic and asymptomatic patients. MATERIALS AND METHODS: Seventy-two consecutive symptomatic patients and sixty-three consecutive asymptomatic patients who underwent CT colonography were enrolled in this study. Non-contrast enhanced axial images were reviewed retrospectively to identify the ECF and classified them as major, moderate or minor important findings according to their potential clinical importance. The frequencies of each classification and ECF were analyzed and compared between two groups (symptomatic and asymptomatic). RESULTS: Eighty-two ECF were identified in 49 (68.1%) of the 72 symptomatic patients. The findings were classified as follows: major (8/49, 11.1%), moderate (17/49, 23.6%), minor (39/49, 54.2%). Sixty ECF were detected in 38 (60.3%) of the 63 asymptomatic patients. The findings were classified as follows: major (2/38, 3.2%), moderate (7/38, 11.1%), minor finding (35/63, 55.6%). No statistically significant differences were found between the two groups (p > 0.05) for the overall ECF frequency. However, a significantly higher frequency of major or moderate ECF was observed in symptomatic patients (30.6%) compared to asymptomatic patients (12.7%) (p < 0.05). CONCLUSION: The overall ECF frequency was similar between symptomatic and asymptomatic patients; however, the frequency of clinically important ECF (major or moderate) was higher in symptomatic patients, compared to asymptomatic patients. This result suggests that the major or moderate ECF required a further work up or treatment in symptomatic patients.
Colonography, Computed Tomographic ; Humans ; Incidental Findings ; Mass Screening ; Retrospective Studies ; Tomography, X-Ray Computed

BACKGROUND/AIMS: Virtual colonoscopy using abdominal spiral computed tomography scanning allows total colonic evaluation with minimal invasiveness. We compared the performance of virtual colonoscopy and colonoscopy for the detection of colorectal polyps. METHODS: We performed colonoscopy before the virtual colonoscopy. Virtual colonoscopy was performed immediately before the colonoscopic polypectomy in 24 adults (16 men and 8 women: mean age, 59 years). RESULTS: A total of 48 polyps were found by colonoscopy. Virtual colonoscopy identified 20 of 28 polyps that were 10 mm or more in diameter (71%), 3 of 4 that were 6 to 9 mm (75%), and 9 of 16 that were 5 mm or smaller (56%). Overall sensitivity of virtual colonoscopy for colorectal polyps was 67%. CONCLUSIONS: Our result of virtual colonoscopy showed lower sensitivity for detection of significant colorectal lesions than previously reported studies. Further large group study may be needed to determine the usefulness of virtual colonoscopy.
Adult ; Colon ; Colonography, Computed Tomographic* ; Colonoscopy* ; Female ; Humans ; Male ; Polyps* ; Tomography, Spiral Computed

Early detection of colon cancer is more important than the actual treatment of colon cancer. Therefore, screening test for high risk patients in a timely fashion is a main factor in early detection of colon cancer. Stool occult test and stool DNA test, barium enema, CT colonography, colonoscopy are used for screening test of colon cancer. The most effective and sensitive test is colonoscopy; it can detect and remove the premalignant lesion of colon cancer and prevent colon cancer. Although colonoscopy is the best way to early detect colon cancer, the technique to detect and remove the premalignant lesion of colon cancer is essential for early detection of colon cancer. In conclusion, the techniques not only to detect but also remove of premalignant lesion are essentially required for colonoscopist.
Barium ; Colon ; Colonic Neoplasms ; Colonography, Computed Tomographic ; Colonoscopy ; DNA ; Enema ; Humans ; Mass Screening

There are approximately one million new cases of colorectal cancer (CRC) per year worldwide, with substantial associated morbidity and mortality. The long natural history of colorectal neoplasia affords the opportunity to use preventive measures to improve survival in this disease. Currently screening for adenomatous polyps and early-stage cancers is the best methodology for improving survival. The increasing knowledge of CRC pathogenesis and its natural history is allowing the development of new tools to identify patients who will benefit most from colon cancer screening and the defining of appropriate surveillance intervals. The guidelines for screening for colorectal neoplasia have recently been substantially revised by several organizations based on developing technologies and a growing body of data on the efficacy of CRC screening.
Adenoma ; Adenomatous Polyps ; Colonic Neoplasms ; Colonography, Computed Tomographic ; Colonoscopy ; Colorectal Neoplasms ; Humans ; Mass Screening ; Natural History

No abstract available.
Adult ; Colonography, Computed Tomographic ; Colorectal Neoplasms/*radiography ; Female ; Humans ; Male ; Middle Aged

OBJECTIVETo explore the value of computed tomography colonography with low radiation dose combined with the enhanced scanning in the diagnosis of colorectal carcinoma.

METHODSA total of 120 patients with clinical suspected colorectal carcinoma undergoing CT colonography and enhanced scanning were randomly divided into routine dose group and low dose group. Conventional colonoscopy and/or surgical pathology were used as the gold standard. Sensitivity, specificity and Youden's index of colorectal cancer TNM staging accuracy were calculated in two groups. The radiation dose of two groups was compared.

RESULTSFor conventional dose and low dose group, in the diagnosis of colorectal cancer (including cancer and adenoma), the sensitivity was 100% (45/45 and 44/44), specificity was 93.3%(14/15) and 87.5%(14/16), the Youden's index was 0.93 and 0.88. There were no significant differences between two groups in T, N and M staging accuracy preoperatively (P>0.05). The effective radiation dose of low dose group was significantly lower than that of conventional dose group [(15.9 ± 4.3) mSv vs. (21.4 ± 5.5) mSv, P<0.01].

CONCLUSIONLow dose CTC combined with enhanced scanning not only reduces the radiation dose of patients, but can possesses similar value of conventional dose CTC in the early diagnosis and preoperative pathological staging of colorectal cancer.

PURPOSE: To perform virtual colonoscopy using electron beam tomography(EBT) in potients in whom a colonicmass was present, and to compare the results with those obtained using barium enema, colonoscopy and grosspathologic specimens. MATERIALS AND METHODS: Ten patients in whom colonic masses were diagnosed by either bariumenema or colonoscopy were involved in this study. There were nine cases of adenocarcinoma and one of tubulovillousadenoma. Using EBT preoperative abdominopelvic CT scans were performed. Axial scans were then three-dimensionallyreconstructed to produce virtual colonoscopic images and were compared with barium enema, colonoscopy and grosspathologic specimens. Virtual colonoscopic images of the masses were classified as either 1)polypoid, 2)sessile,3)fungating, or 4)annular constrictive. We also determined whether ulcers were present within the lesions andwhether there was obstruction. RESULT: After virtval colonoscopy, two lesions were classified as polypoid, oneas sessile, five as fungating and two as annular constrictive. Virtual colonoscopic images showed good correlationwith the findings of barium enema, colonoscopy and gross pathologic specimens. Three of six ulcerative lesionswere observed on colonoscopy; in seven adenocarcinomas with partial or total luminal obstruction, virtualcolonoscopy visualized the colon beyond the obstructed sites. In one case, barium contrast failed to pass throughthe obstructed portion and in six cases, the colonoscope similarly failed. CONCLUSION: Virtual colonoscopiescorrelated well with barium enema, colonoscopy and gross patholoic specimens. They provide three dimensionalimages of colonic masses and are helpful for the evaluation of obstructive lesions.
Adenocarcinoma ; Barium* ; Colon ; Colonography, Computed Tomographic* ; Colonoscopes ; Colonoscopy* ; Enema* ; Humans ; Pathology* ; Phenobarbital ; Tomography, X-Ray Computed ; Ulcer