Colorectal cancer imaging: a challenge for radiologists

Colonoscopic perforation leading to a diagnosis of Ehlers Danlos syndrome type IV: a case report and review of the literature

Introduction

Colonoscopic perforation is a rare but serious complication of colonoscopy. Factors known to increase the risk of perforation include colonic strictures, extensive diverticulosis, and friable tissues. We describe the case of a man who was found to have perforation of the sigmoid colon secondary to an undiagnosed connective tissue disorder (Ehlers-Danlos syndrome type IV) while undergoing surveillance for hereditary non-polyposis colorectal cancer.

Case presentation

A 33-year-old Caucasian man presented to our hospital with an acute abdomen following a colonoscopy five days earlier as part of hereditary non-polyposis colorectal cancer screening. His medical history included bilateral clubfoot. His physical examination findings suggested left iliac fossa peritonitis. A computed tomographic scan revealed perforation of the sigmoid colon and incidentally a right common iliac artery aneurysm as well. Hartmann's procedure was performed during laparotomy. The patient recovered well post-operatively and was discharged. Reversal of the Hartmann's procedure was performed six months later. This procedure was challenging because of dense adhesions and friable bowel. The histology of bowel specimens from this surgery revealed thinning and fibrosis of the muscularis externa. The patient was subsequently noted to have transparency of truncal skin with easily visible vessels. An underlying collagen vascular disorder was suspected, and genetic testing revealed a mutation in the collagen type III, α1 (COL3A1) gene, which is consistent with a diagnosis of Ehlers-Danlos syndrome type IV.

Conclusions

Ehlers-Danlos syndrome type IV, the vascular type, is a rare disorder caused by mutations in the COL3A1 gene on chromosome 2q31. It is characterized by translucent skin, clubfoot, and the potentially fatal complications of spontaneous large vessel rupture, although spontaneous uterine and colonic perforations have also been reported in the literature. The present case presentation describes the identification of Ehlers-Danlos syndrome type IV in a patient with a non-spontaneous colonic perforation secondary to an invasive investigation for another hereditary disorder pre-disposing him to colorectal cancer. Invasive procedures such as arteriograms and endoscopies are relatively contra-indicated in Ehlers-Danlos syndrome type IV. Alternatives with a lower risk of perforation, such as computed tomographic colonography, need to be considered for patients requiring ongoing colorectal cancer surveillance. Furthermore, management of vascular aneurysms in patients with Ehlers-Danlos syndrome type IV requires consideration of the risks of endovascular stenting, as opposed to open surgical intervention, because of tissue friability. Genetic and reproductive counseling should be offered to affected individuals and their families.

Whole-body PET/CT-colonography: a possible new concept for colorectal cancer staging

BACKGROUND

Colorectal cancer (CRC) is a leading cause of death, and necessitates a conjointly performed staging. Until now, a multi-step-examination including optical colonoscopy, cross-sectional and functional imaging is recommended. However, a single examination for whole-body staging with a dedicated CRC staging protocol is desirable. Thus, we developed and evaluated a combined whole-body PET/CT-colonography protocol for dedicated CRC staging in routine clinical use.

METHODS

We integrated CT-colonography into a whole-body PET/CT protocol to achieve a specific "all-in-one" examination for patients suspected of having CRC. After oral and rectal bowel distension, PET/CT-colonography has been performed in 55 patients. All patients had optical colonoscopy one day before PET/CT. PET/CT data sets were evaluated concerning detection and evaluation of colorectal tumour sites, lymph nodes and distant metastases; these results were compared to the results of CT-colonography alone. Surgical resection and/or biopsy served as standards of reference in all patients.

RESULTS

All examinations were fully diagnostic and well tolerated by the patients. PET/CT-colonography showed highly accurate results for overall TNM-evaluation and was significantly more accurate than CT-colonography alone.

CONCLUSIONS

Staging patients with whole-body PET/CT-colonography is technically feasible and accurate. Patients with incomplete colonoscopy or potential synchronous bowel lesions might benefit from this approach.

Water enema computed tomography: diagnostic tool in suspicion of colorectal tumor

OBJECTIVES

The aim of this study was to assess the accuracy of water enema multi-row computed tomography for detecting clinically suspected colorectal tumor.

PATIENTS AND METHODS

A water enema multi-row computed tomography (WE-MR-CT) was performed in 128 consecutive patients (71 women, mean age 67.7 years) referred for suspicion of colorectal cancer. We defined at least one centimeter size of the lesion as the threshold of detection. The results of WE-MR-CT were compared with the diagnosis obtained by colonoscopy, pathology or clinical follow-up.

RESULTS

The overall sensitivity and specificity of water enema multi-row CT in identifying patients with colorectal lesions were 95.5% and 93.5%, respectively. The negative predictive value was 98.8% for a 10-mm threshold lesion size. WE-MR-CT allowed identifying synchronous lesions in three cases.

CONCLUSIONS

WE-MR-CT can accurately detect supracentimetric colorectal tumors. The performance of this technique should be further evaluated in prospective studies.

Whole body positron emission tomography/computed tomography (PET/CT) tumour staging with integrated PET/CT colonography: technical feasibility and first experiences in patients with colorectal cancer

AIM

The aim of this study was to implement an imaging protocol for positron emission tomography/computed tomography (PET/CT) colonography and to combine this protocol with whole body PET/CT tumour staging for a single whole body examination for routine clinical use.

SUBJECTS AND METHODS

A whole body PET/CT protocol for tumour staging and a protocol for PET/CT colonography were integrated into one examination. Fourteen prospective patients with suspected colorectal cancer underwent whole body PET/CT after aqueous bowel distension and pharmacological bowel relaxation. Colonoscopy and histopathology served as the standards of reference in all patients.

RESULTS

The modified PET/CT examination detected all but one lesion in the colon. One additional lesion was detected in a patient with incomplete colonoscopy due to high grade luminal stenosis. One polyp with malignant conversion was identified with the modified PET/CT protocol. PET/CT colonography proved accurate in local lymph node staging and staged nine out of 11 patients correctly. Six additional extracolonic tumour sites were detected based on the whole body staging approach.

CONCLUSION

Whole body PET/CT with integrated colonography is technically feasible for whole body staging in patients with colorectal cancer. Based on these initial diagnostic experiences, this integrated protocol may be of substantial benefit in staging patients with colorectal cancer, focusing on patients with incomplete colonoscopy and those with small synchronous bowel lesions.

Barium enema "shoulder" sign: a useful predictor of pericolonic fat invasion in colorectal cancer

PURPOSE

We aimed to determine the presence of the "shoulder" sign in prediction of pericolonic fat invasion on double-contrast barium enema (DCBE) studies in colorectal cancer.

MATERIALS AND METHODS

Patients at our institution with apparent colorectal cancer were identified from a computer search of both radiological and surgical pathology records during a recent 30-month period. The presence of a shoulder sign was defined as a tumor margin having an abrupt transition from the intraluminal component to the adjacent normal mucosa, forming a shouldered edge on barium studies.

RESULTS

A total of 49 patients (53 lesions) for whom the DCBE studies and surgical pathology records were available for review were proven to have colorectal carcinomas. DCBE studies revealed that 45 patients with lesions (85%) presented with a "shoulder" sign. All of these lesions were correctly diagnosed as colorectal cancer. Of these, 89% had pericolonic fat invasion and 44% had regional lymph node metastases. Of lesions without a shoulder sign, 25% had pericolonic fat invasion and 25% had nodal metastases.

CONCLUSION

The presence of shoulder sign detected with barium enema can be a useful predictor of pericolonic fat invasion in colorectal cancer.

Colorectal cancer screening with double-contrast barium enema: a national survey of diagnostic radiologists

OBJECTIVE

This article describes diagnostic radiologists' colorectal cancer screening activities and beliefs about screening effectiveness and future capacity for screening with double-contrast barium enema, and compares radiologists' opinions about colorectal cancer screening with those of primary care physicians.

MATERIALS AND METHODS

We surveyed a nationally representative sample of diagnostic radiologists. Of 381 eligible radiologists, 312 (82%) responded. Descriptive statistics and chi-square tests were used to assess radiologists' opinions about double-contrast barium enema volume and capacity and to compare radiologists' beliefs about colorectal cancer screening with those of primary care physicians. Logistic regression was used to identify characteristics of radiologists who receive referrals for or perform a higher volume of screening double-contrast barium enema and of those who expect the volume of double-contrast barium enemas to increase.

RESULTS

Seventy-five percent of radiologists said that double-contrast barium enema is a "very effective" colorectal cancer screening procedure compared with 33% of primary care physicians. Although 86% of radiologists reported performing one or more screening double-contrast barium enema procedures during a typical month, only 27% indicated that they did so 11 or more times. Fifteen percent of radiologists said that their double-contrast barium enema volume had increased over the past 3 years, and 50% expect an increase over the next 3 years. Only 8% said that the capacity of facilities and personnel to meet the demand for double-contrast barium enemas in their geographic area of practice is inadequate. Geographic region and belief in double-contrast barium enema efficacy were predictors of double-contrast barium enema volume and referrals.

CONCLUSION

Most diagnostic radiologists perform colorectal cancer screening with double-contrast barium enema, but procedure volumes are modest. Because primary care physicians view double-contrast barium enema less positively than do radiologists, radiologists' expectations for an increased volume of double-contrast barium enemas over the next few years may not be realized.

Radiology of colorectal cancer

In the past 20 years, the radiology of colorectal cancer has evolved from the barium enema to advanced imaging modalities like phased array magnetic resonance imaging (MRI), virtual colonoscopy and positron emission tomography (PET). Nowadays, primary rectal cancers are preferably imaged with transrectal ultrasound or MRI, while barium enema is still the most often used technique for imaging of colonic cancers. Virtual colonoscopy is rapidly evolving and might considerably change the imaging of colorectal cancer in the near future. The use of virtual colonoscopy for screening purposes and imaging of the colon in occlusive cancer or incomplete colonoscopies is currently under evaluation. The main role of PET is in detecting tumour recurrences, both locally and distantly. Techniques to fuse cross-sectional anatomical (computer tomography (CT) and MRI) and functional (PET) images are being developed. Apart from diagnostic imaging, the radiologists has added image-guided minimally invasive treatments of colorectal liver metastases to their arsenal. The radio-frequency ablation technique is now widely available, and can be used during laparotomy or percutaneously in selected cases.

Colon cancer screening with virtual colonoscopy: promise, polyps, politics

Virtual colonoscopy (CT colonography) promises to become a primary method for colorectal cancer screening and return radiologists to a major role in colon cancer prevention. Results from major centers in the United States show accuracy to be comparable to conventional colonoscopy for detection of polyps of significant size--that is, greater than 10 mm--with few false-positives. The advent of virtual colonoscopy has also heightened awareness of the natural history of colonic polyps, particularly in terms of identifying an appropriate target size for detection in colorectal screening programs. Small polyps (<10 mm) are often either hyperplastic on histology or are unlikely to progress to frank cancer in the patient's lifetime and are therefore of little clinical significance for the average adult. Thus, the rationale for detecting and removing each and every colonic polyp regardless of size has come under increasing scrutiny in the context of cost-benefit analysis of various test strategies for colorectal cancer screening. Virtual colonoscopy may allow patients to obtain reliable information about the status of their colonic mucosa noninvasively and thus make a more informed decision as to whether to proceed to conventional colonoscopy for polypectomy.

Barium enema and endoscopy for the detection of colorectal neoplasia: sensitivity, specificity, complications and its determinants

AIM

To analyse sensitivity, specificity and complication rate of endoscopy, and barium enema for the detection of colorectal neoplasia.

MATERIALS AND METHODS

A MEDLINE search was performed (1980-2000) directed at the endoscopic and radiologic literature on barium enema. Articles were selected based on the type of study, availability of sensitivity and specificity values in sizeable patient groups, and reports on complications. Sixty articles were included in the analysis.

RESULTS

Endoscopy proved to have superior sensitivity for polyps in patients at high-risk for colorectal neoplasia. The role of endoscopy and radiology in average-risk screening populations is not known. Sensitivity and specificity rates ranged widely, probably due to bias. For the detection of small polyps endoscopy has superior performance, whereas sensitivity is similar for endoscopy and barium enema for the detection of larger (>1 cm) polyps and tumours. Overall, endoscopy is associated with a higher complication rate.

CONCLUSION

Endoscopy is the preferred detection method in high-risk patients. The role of endoscopy and radiology in a screening setting requires evaluation. This review provides the test characteristics of endoscopy and radiology which are relevant for a cost-effectiveness analysis. Double-contrast barium enema may play an important role for screening purposes, owing to its good sensitivity for detecting larger (>1 cm) polyps and its lack of major complications. de Zwart, I. M.et al. (2001). Clinical Radiology56, 401-409.

Cost-effectiveness of colorectal cancer screening

PURPOSE

To determine the most cost-effective colorectal cancer screening strategy costing less than $100,000 per life-year saved and to determine how available strategies compare with each other.

MATERIALS AND METHODS

Standardized methods were used to calculate incremental cost-effectiveness ratios (ICERs) from published estimates of cost and effectiveness of colorectal cancer screening strategies, and the direction and magnitude of any effect on the ratio from parameter estimate adjustments based on literature values were estimated.

RESULTS

Strategies in which double-contrast barium enema examination was performed emerged as optimal from all studies included. In average-risk individuals, screening with double-contrast barium enema examination every 3 years, or every 5 years with annual fecal occult blood testing, had an ICER of less than $55,600 per life-year saved. However, double-contrast barium enema examination screening every 3 years plus annual fecal occult blood testing had an ICER of more than $100,000 per life-year saved. Colonoscopic screening had an ICER of more than $100,000 per life-year saved, was dominated by other screening strategies, and offered less benefit than did double-contrast barium enema examination screening.

CONCLUSION

Double-contrast barium enema examination can be a cost-effective component of colorectal cancer screening, but further modeling efforts are necessary.