Segmental wall thickening in the colonic loop distal to colonic carcinoma at CT: importance and histopathologic correlation

Colonoscopy for colonic wall thickening at computed tomography: a worthwhile pursuit?

BACKGROUND

In the absence of official guidance for the management of colonic wall thickening identified by computed tomography (CT), a common clinical dilemma surrounds the volume of colonoscopies subsequently performed.

METHODS

To identify whether colonic wall thickening identified at CT consistently warrants colonoscopy, consecutive colonoscopies performed at Leeds Teaching Hospitals Trust in 2008 and recorded as "possible colonic lesion on cross-sectional abdominal CT" in an endoscopic database were retrospectively analyzed. Clinical, radiologic, colonoscopic, and histologic data were obtained from medical records.

RESULTS

Of 4,702 colonoscopies, 94 (2%) had a full data set meeting the inclusion criteria. The primary diagnoses were normal condition (n = 11, 11.7%), adenocarcinoma (n = 25, 26.6%), adenoma (n = 23, 24.5%), diverticular disease (n = 12, 12.8%), nonspecific colitis (n = 6, 6.4%), Crohn's disease (n = 4, 4.3%), and hyperplastic polyp (n = 3, 3.2%). Computed tomography and colonoscopy were concordant for specific pathology in 79.8% of the cases (n = 75). Compared with diagnosis after histology, colonoscopy alone correctly identified specific pathology in 18.1% of the cases (n = 17), and CT alone was correct in 4.3% of the cases (n = 4)), whereas both were incorrect in 3.2% of the cases (n = 3). Computed tomography had a sensitivity of 72.3% (95% confidence interval [95% CI], 61.9-80.8%), a specificity of 96.5% (95% CI, 94.9-97.6%), a positive predictive value of 72.3%, and a negative predictive value of 96.5%. In 63.8% of the cases (n = 60), CT identified pathology necessitating further intervention at the time of colonoscopy or afterward, and in 28.7% of the cases (n = 27), CT identified pathology requiring no additional intervention. In the remaining 7.4% of the cases (n = 7), CT detected no new pathology.

CONCLUSION

Computed tomography is highly predictive of colonic pathology compared with final outcome after colonoscopy and biopsy. For patients without a pre-existing diagnosis, colonic wall thickening demonstrated at CT warrants further investigation with colonoscopy.

CT findings of colonic complications associated with colon cancer

A broad spectrum of colonic complications can occur in patients with colon cancer. Clinically, some of these complications can obscure the presence of underlying malignancies in the colon and these complications may require emergency surgical management. The complications of the colon that can be associated with colon cancer include obstruction, perforation, abscess formation, acute appendicitis, ischemic colitis and intussusception. Although the majority of these complications only rarely occur, familiarity with the various manifestations of colon cancer complications will facilitate making an accurate diagnosis and administering prompt management in these situations. The purpose of this pictorial essay is to review the CT appearance of the colonic complications associated with colon cancer.

Imaging of ischemic colitis

Ischemic colitis accounts for more than half of all cases of gastrointestinal ischemia and constitutes between 1 per 2000 and 3 per 1000 acute hospital admission. It typically affects elderly patients, being a frequent cause of rectal bleeding, abdominal pain, and diarrhea. This article describes the epidemiology, physiology, and pathology of this underdiagnosed condition; reviews the clinical patterns of this disease, which constitute a key diagnostic point in patients who have a thickening of the colonic wall; and describes the ultrasound (US) and CT findings, pitfalls, and differential diagnoses of ischemic colitis. The value and limitations of US and CT at the different diagnostic stages is discussed.

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.

Colonic Wall Thickening on Computed Tomography Scan and Clinical Correlation. Does it Suggest the Presence of an Underlying Neoplasia?

The widespread use of computed tomography (CT) scanning technology frequently leads to the incidental discovery of thickened bowel wall. The clinical significance of such a CT scan finding is largely under-investigated. The purpose of our study was to determine the incidence of significant clinical pathology and, particularly, neoplasia in patients with abnormally thickened bowel on CT scan examination. This is a single institution retrospective analysis of patients that underwent CT scanning of their abdomen. The radiological picture was correlated with colonoscopic findings. A total of 40 consecutive patients with thickened bowel on CT scan that also underwent colonoscopy were identified and their records were reviewed. Thirty-five patients had no history of previous gastrointestinal disorder and form our study group. The median age of the patients was 69 years (range, 24–97 years). There were 26 female and 9 male patients. The incidental CT finding of bowel wall thickening was the only reason for the colonoscopy in 14 (35%) out of the 40 patients. Eight (23%) patients with thick bowel had colonic neoplasia based on pathology. Five (14%) patients had invasive adenocarcinoma of the colon. Four (11%) of the 5 patients with colon adenocarcinoma did not have any associated gastrointestinal symptoms or signs. One (3%) patient had lymphoma of the colon and two (6%) had benign polyps. Colonoscopy was unremarkable in 10 (28%) patients. The incidental finding of colonic thickening on CT imaging could be associated with underlying colonic malignancy and, more importantly, represent the initial disease presentation. Therefore, we propose that these patients should undergo colonoscopy.

Normal colonic wall thickness at CT and its relation to colonic distension

PURPOSE

The purpose of this work was to analyze the relation between normal colonic wall thickness at CT and local colonic distension.

METHOD

One hundred consecutively acquired patients were included in our study. All patients were asymptomatic regarding their intestine, and their history was always negative for intestinal disease. All CT examinations were performed for other reasons than intestinal disease. Colonic wall thickness at CT was measured digitally in every patient at four locations and set in relation to the local colonic distension.

RESULTS

The normal colonic wall thickness ranged from 0 to 2 mm in colonic segments with a diameter of >/=4-6 cm, from 0.2 to 2.5 mm in colonic segments with a diameter of 3-4 cm, from 0.3 to 4 mm in colonic segments with a diameter of 2-3 cm, and from 0.5 to 5 mm in colonic segments with a diameter of 1-2 cm. Maximal colonic wall thickness ranged up to 6 and 8 mm in the proximal and distal colon, respectively, if the measured colonic segment showed a luminal width of <1 cm according to contraction.

DISCUSSION

The normal colonic wall thickness at CT should be regarded as a dynamic value that stays in clear relation to the local colonic distension. In contracted colonic segments, a colonic wall thickness of 6-8 mm may still be normal. On the other hand, a colonic wall measuring 5 and 3 mm should be regarded as thickened if found in colonic segments with a luminal width of >2 and 4 cm, respectively.