Dutch docs use CT colonography to distinguish carcinoma from diverticulosis

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 - CT colonography carcinoma
Typical appearance of colonic carcinoma on CT colonographic image in an 89-year-old woman with changed bowel habits. Image shows no diverticula but does show shoulder phenomenon (arrow tip), complete distortion of fold pattern, and straightened growth pattern.
Source: Radiology 2015;275:127–135

Features found at CT colonography have proven effective at discriminating between sigmoid cancer and diverticular disease, a discovery that could reduce unnecessary medical procedures and improve patient care, according to results of a study published in the April issue of  Radiology.

The use of CT colonography continues to grow in popularity among clinicians, with studies showing the technique to be just as effective at detecting cancers and imaging the colon as traditional colonoscopy. Though features are sometimes ambiguous, determining the correct diagnosis when using CT colonography is critical, according to lead author Leonie Lips, MD, of VieCuri Medical Centre in Vienlo, the Netherlands, and colleagues. “When confronted with an apparent mass or mass-like thickening involving the sigmoid colon at CT colonography, it is important to distinguish carcinoma from chronic diverticular disease, as the clinical implications and management greatly differ,” they wrote. “If cases of chronic diverticular disease of the sigmoid colon can be diagnosed confidently and prospectively at CT colonography, including exclusion of cancer, unnecessary diagnostic endoscopy, surgery, or both may be avoided.”

The researchers set out to identify which morphologic findings at CT colonography most reliably enable doctors to differentiate between chronic diverticular disease and sigmoid carcinoma. To do so, they performed a retrospective analysis of 212 patients from two large nonacademic teaching hospitals in the Netherlands with focal mass-like findings in the sigmoid colon at CT colonography. Four readers scored the patients’ CT colonography studies according to presence or absence of potential discriminators.

The results showed that one feature found at CT colonography was particularly effective at distinguishing between diverticulosis and sigmoid cancers. “Absence of visualized diverticula within the thickened sigmoid segment is the most useful discriminator in the diagnosis of cancer rather than diverticular disease, with high negative predictive value and positive predictive value (0.95 and 0.93, respectively),” the researchers wrote. Their results also showed that a combination of an absence of diverticula and the presence of shouldering phenomenon shows a high diagnostic certainty (93 percent) for carcinoma.

All of this adds up to improved disease management and improved overall patient experience, according to Lips and colleagues. “Careful analysis at CT colonography with these morphologic features in mind may lead to improved diagnosis and may reduce the number of unnecessary colonoscopic and surgical procedures.”