Preliminary study on MR colonography with air enema in detection of colorectal neoplasms

The few studies on MR colonography with air enema involved feasibility of bowel distention and imaging quality and lacked detection sensitivity of colorectal neoplasms. The purpose of this prospective study was to assess the detection sensitivity of colorectal neoplasms with the three-dimensional Fourier transform fast spoiled gradient-recalled MR colonography with air enema.

A total of 30 patients scheduled for optical colonoscopy due to rectal bleeding, positive fecal occult blood test results or altered bowel habits were recruited and successfully underwent entire colorectal examinations with three-dimensional Fourier transform fast spoiled gradient-recalled MR colonography and subsequent optical colonoscopy on the same day. Detection sensitivity of colorectal neoplasms with MR colonography was statistically analyzed on a per-neoplasm size basis by using findings from optical colonoscopy and histopathological examinations as the reference standards.

Seventy-six neoplasms were detected with optical colonoscopy, consisting of 1 mm-5 mm (n = 11), 6 mm-9 mm (n = 29) and ≥ 10 mm (n = 36) in diameter. Detection sensitivities of 1 mm-5 mm, 6 mm-9 mm, ≥ 10 mm and ≥ 6 mm colorectal neoplasms with MR colonography were 9.1%, 75.9%, 100% and 89.2%, respectively; overall detection sensitivity for all sizes colorectal neoplasms was 77.6%.

Detection sensitivity of three-dimensional Fourier transform fast spoiled gradient-recalled MR colonography with air enema is low for 1 mm-5 mm colorectal neoplasms, but the detection sensitivity is 89.2% for ≥ 6 mm neoplasms, and all ≥ 10 mm neoplasms could be detected.