Ultrasound, CT and colonoscopy of colonic cancer

Role of Hydrocolonic Sonography in the Detection of Colonic Neoplastic Lesions

This article evaluates the role of hydrocolonic sonography in the study of colon neoplastic lesions in daily gastroenterology practice. Consecutive patients referred for optical colonoscopy were randomly and prospectively enrolled to hydrocolonic sonography. All patients went through hydrocolonic sonography (HS) before optical colonoscopy (OS). In total, 108 patients (57 men), with an average age of 68.9 years, participated in the study. Indications for colonoscopy were colorectal cancer screening (50.0%), unspecific abdominal symptoms (45.4%), and liver metastasis or suspicious lymph nodes (4.6%). Inspection of the entire colon was possible in 86.8% of patients by OC and 89.6% of patients by HS. Globally, the sensitivity and specificity of HS in polyp detection were 24.2% and 99.7%, respectively. For polyps >10 mm, hydrocolonic sonography achieved sensitivity, specificity, positive predictive value, and negative predictive value of 80.0%, 99.7%, 92.8%, and 99.5%, respectively. Optical colonoscopy detected 12 cancers, all identified with hydrocolonic sonography, showing a sensitivity and specificity of 100%. The technique was well tolerated by 94.3% of patients. Hydrocolonic sonography is feasible, safe, well tolerated, and inexpensive, allowing the detection of polyps larger than 10 mm and colon cancer with good accuracy in this study population. In the appropriate setting, it may be a complementary technique in the study of the colon.

Sonographic assessments of gastrointestinal and biliary functions

Ultrasound has been established as a routine work-up imaging method in abdominal diseases. It assesses the morphology of intra-abdominal organs and depicts the normal and pathological anatomy of the gastrointestinal tract as well as of the biliopancreatic system. Ultrasound is the method of choice for visualisation of motion sequences since it is, in contrast to other imaging methods, a real-time method. The non-invasiveness and the repeatability of the method are important advantages when performing investigations of functional processes. Therefore, ultrasound is most suited for functional studies. Up to now, functional ultrasound and its potential have been undervalued. Functional ultrasound provides a widely available method to increase our understanding of functional processes and motility. The authors review the options of functional ultrasound and discuss its practical relevance.

Accuracy and Cost Comparison of Ultrasound Versus Alternative Imaging Modalities, Including CT, MR, PET, and Angiography

Ultrasound (US) has become widely used in clinical medicine for the diagnosis of a variety of disease processes. The unique ability of US to provide accurate information through an efficacious, painless, portable, and nonionizing method has expanded its role and application in diverse medical settings. Given the current economic environment and the related interest in creating the greatest value for health care expenditures, US has been evaluated to compare its clinical accuracy/efficacy and cost-effectiveness versus other imaging modalities. The following literature review reports the results of research studies aimed at comparing the accuracy/efficacy and cost of US versus alternative imaging modalities, including magnetic resonance imaging, computed tomography, contrast angiography, and single-photon emission computed tomography.

The use of minimal preparation computed tomography for the primary investigation of colon cancer in frail or elderly patients

AIM

To assess the place of computed tomography (CT) of the colon in frail or elderly patients with symptoms suggestive of colon cancer.

METHOD

A total of 195 patients (median age 76 years) underwent CT of the abdomen and pelvis following the administration of positive oral contrast medium but no bowel preparation. All had symptoms suggestive of colon cancer. CT findings were classified as normal/diverticular disease (DD), possible colon cancer, definite colon cancer or extracolonic pathology. Accuracy of CT was assessed against patient outcome. Association between symptoms and colon cancer was assessed by chi-squared test.

RESULTS

There were 47 deaths and median follow up for those alive was 16 months. Overall sensitivity of CT was 100% and specificity 87% for detection of colon cancer. One hundred and ten normal/DD CT examinations had no significant bowel lesion on follow up. Of 12 cases defined as 'definite cancers' on CT, there were nine colon cancers, two extracolonic cancers, and one normal. Of 23 'possible cancers' on CT, there were two colon cancers, three DD masses and 18 normal/DD. Fifty examinations had extracolonic findings including 33 (17%) cases of significant abdominal disease. CT findings led to a halt in investigations in 115 cases (59%), colonoscopy in 18 (9%) cases and surgery in 16 (8%) cases. None of the symptoms present showed a significant association with colon cancer (all P > 0.05).

CONCLUSION

Minimal preparation CT is a non-invasive and sensitive method for investigating colon cancer in frail or elderly patients. It has a 100% negative predictive value and also detects a large number of extracolonic lesions.

CT and bowel disease

CT has now come of age in the detection and demonstration of bowel pathology and is likely to supplant traditional imaging techniques further in the future. Its role here has been greatly aided by the advent of fast spiral CT sequences and, with the development of even faster multidetector CT systems, this can only increase.