CT colonography: the real deal

Is barium enema examination negligible for the management of colorectal cancer? Comparison with conventional colonoscopy and magnifying colonoscopy

PURPOSE

The aim of this investigation was to evaluate the clinical value of barium enema (BE) examination for the management of colorectal epithelial neoplasms.

METHODS

We reviewed the colonoscopy records at our institution from 2014 to 2019 and identified cases of endoscopically or surgically resected colorectal epithelial neoplasms evaluated by BE, conventional colonoscopy, magnifying narrow-band imaging colonoscopy (M-NBI), and magnifying chromoendoscopy (MCE). The yield of each modality for the diagnosis of massively submucosal invasive (mSM) colorectal cancer was evaluated by a receiver-operating characteristic analysis including the area under the curve (AUC).

RESULTS

We analyzed the records of 105 patients (17 adenomas, 53 high-grade dysplasias (HGDs), and 35 cancers). Smooth surface, irregularity in depression, and eccentric deformity on the profile view with BE were observed more frequently in mSM cancers than adenomas/HGDs/slightly submucosal invasive cancers (p < 0.01). The AUC of BE was 0.8355, the value of which was not different from the other three modalities (conventional colonoscopy 0.7678; M-NBI 0.7835; MCE 0.8376). Although the specificity, PPV, and accuracy of BE were lower than those of M-NBI and MCE, the sensitivity and NPV of BE were the highest among the four types of examinations.

CONCLUSION

BE is still available and may serve as a supplementary modality for the diagnosis of mSM cancers.

Current role and future potential of computed tomographic colonography for colorectal polyp detection and colon cancer screening-incidental findings

AIM

In this retrospective study, we assess the current role and future potential of computed tomographic (CT) colonography as a viable alternative imaging tool for colorectal polyp detection and colon cancer screening.

MATERIALS AND METHODS

Twenty patients have undergone virtual colonographic examinations with 64-multidetector-row spiral CT (MDCT), and three-dimensional images were created on a separate workstation that had the appropriate software for image processing. Images were reviewed by a radiologist, and anatomic division of the entire colon was used to locate the suspected lesions. Characteristics of bowel preparation, intracolonic, extracolonic, and incidental findings were noted, too.

RESULTS

Ten of the 20 patients (50%) had a positive CT colonography for polypoid lesions. Those lesions were distributed into the cecum (4 cases), colon ascendens (2 cases), colon descendens (2 cases), and sigma (2 cases). In 80%, bowel preparation was good, in 15% moderate, and in 5% inadequate. Furthermore, CT scan noted in total 20 incidental findings.

CONCLUSION

CT colonography is currently a viable alternative imaging tool for colorectal polyp detection. There are several clinical situations where CT colonography may play an important role in patient care. These include for example evaluation of the colon after an incomplete conventional colonoscopic examination or evaluation in patients who are clinically unfit to undergo conventional colonoscopy. At centers where there is expertise in data acquisition and interpretation, CT colonography is being offered as a routine imaging examination. With continued improvements in bowel preparation, colonic distention, and CT colonography interpretation by sufficient numbers of radiologists this technology might have a substantial influence on colon cancer screening.

Value of multi-slice computed tomography in preoperative "one-station-style" examination for colon cancer

AIM: To assess the value of three-phase contrasted multi-slice computed tomography (MSCT) pneumocolon in preoperative examina-tion of colon cancer.

METHODS: Sixty-three patients with colonic cancer underwent plain MSCT pneumocolon and multiphase contrasted MSCT within 1 week before operation. Contrasted MSCT scans were performed using 16-slices CT system (Toshiba aquilion16) 22 s (phaseⅠ), 37-40 s (phaseⅡ) and 60 s (phase Ⅲ) after intravenous administration of contrast medium. Images were then obtained by CT colonography (CTC), X-ray projection (XRP), multi-planar reformation (MPR), surface shadow display (SSD), CT angiography (CTA) in post-procession workstation. The results were comparatively analyzed with the surgical pathology.

RESULTS: Sixty-four cancer lesions were detected on CT images and in surgery. They located in ascending colon (18 lesions), hepatic flexure of colon (2 lesions), transverse colon (4 lesions), splenic flexure of colon (2 lesions), descending colon (6 lesions), sigmoid (20 lesions, of which 5 lesions in the injunction of sigmoid and rectum), and rectum (12 lesions). Extracolonic diseases were found in 16 patients by MSCT or surgery. On multi-phase contrasted CT images, colon caner lesions demonstrated homogeneous or inhomogenous enhancement, and the absolutely increased peaks in CT density were at phase Ⅱ (30 lesions), phase Ⅱ-Ⅲ (17 lesions), phase Ⅲ (13 lesions) and phaseⅠ-Ⅲ (4 lesions). CTA detected blood-supplying artery of 58 cancer lesions (90.6%). The sensitivity, specificity and positive accuracy were 100%, 64.2%, and 92.1% respectively, for pericolonic fat involvement, and 78.5%, 86.7%, and 86.1% respectively, for abdominal metastasis-positive lymph-nodes.

CONCLUSION: MSCT pneumocolon and preoperative three-phase contrasted CT can provide information about tumor location, number, stage, blood-supplying artery and extracolonic diseases.

Meta-analysis comparing CT colonography, air contrast barium enema, and colonoscopy

INTRODUCTION

Published studies have reported a wide range of sensitivities and specificities for computed tomographic (CT) colonography for polyp detection, generating controversy regarding its diagnostic accuracy.

METHODS

A meta-analysis of published studies comparing the accuracies of CT colonography and colonoscopy for polyp detection was performed. The pooled per-patient sensitivities and specificities were calculated at various thresholds for polyp size. Summary receiver operating characteristic (sROC) curves were also constructed.

RESULTS

Thirty studies were included in the meta-analysis of CT colonography. The pooled per-patient sensitivity of CT colonography was higher for polyps greater than 10 mm (0.82, 95% confidence interval [CI], 0.76-0.88) compared with polyps 6 to 10 mm (0.63, 95% CI, 0.52-0.75) and polyps 0 to 5 mm (0.56, 95% CI, 0.42-0.70). Similarly, the exact area under the sROC curve (area +/- standard error) was higher using a threshold greater than 10 mm (0.898 +/- 0.063) compared with thresholds of greater than 5 mm and any size (0.884 +/- 0.033 and 0.822 +/- 0.059, respectively). There were no significant differences in the diagnostic characteristics of 2-dimensional versus 3-dimensional CT colonography. At a threshold greater than 5 mm, the exact area under the sROC curve was significantly higher for endoscopic colonoscopy compared with CT colonography (0.998 +/- 0.006 vs 0.884 +/- 0.033, P < .005).

CONCLUSIONS

CT colonography has a reasonable sensitivity and specificity for detecting large polyps but was less accurate than endoscopic colonoscopy for smaller polyps. Thus, CT colonography may not be a reasonable alternative in situations in which a small polyp may be clinically relevant.

Evaluation of benign and malignant rectal lesions with CT colonography and endoscopic correlation

Colorectal carcinoma is a significant cause of death from cancer in the United States, and early detection and treatment are critical. Computed tomographic (CT) colonography is a noninvasive, rapidly evolving technique that is a potential alternative to conventional colonoscopy for colorectal cancer screening. Rectal disease (eg, polyps, cancerous lesions, extramucosal lesions, inflammatory disease) can be especially challenging to diagnose with CT colonography because of several factors that can simulate or obscure the disease (eg, over- or underdistention, rectal tube, stool, artifacts). Familiarity with the spectrum of rectal diseases and with the potential pitfalls and technical limitations of CT colonography will help minimize interpretative and perceptual errors.