The efficacy of spectral CT colonography in detecting small phantom polyps
YU Xiao-kun1, SUN Hao-ran1, ZHANG Li-ren2, LI Lei3
1.Department of Radiology, Tianjin Medical University General Hospital, Tianjin 300052, China;2.Department of Radiology, TEDA International Cardiovascular Hospital, Tianjin 300457, China;3.Department of Radiology, Tianjin Fifth Center Hospital, Tianjin 300450, China
Abstract：Objective: To evaluate the efficacy of CT colonography with spectral imaging in detecting small phantom colonic polyps and find the best single spectral images. Materials and Methods: Two segments of twenty artificial polyps sized from 1 mm to 10 mm(ten sized smaller than 5 mm and ten sized over 5 mm) were established by ligation in a segment of porcine colon. The phantom colon were inflated and immerged into 0.1% iodine solution. Volume data were acquired on a 64-multi detector gemstone CT scanner single spectral images at 45, 60, 75, 90, 105, 120 and 135 keV were reconstructed. CT virtual endoscopy(CTVE), multiplanar reformation(MPR) and virtual dissection(VD) models were reconstructed. Two radiologists blinded to the polyps location assessed every image setting. Contrast to noise ratios(CNR) as well as detecting rates of the polyps were calculated and compared statistically among different acquisitions. Results: The phantom study revealed that the detecting rates of colonic polyps were higher than conventional for those polyps less than 5 mm(P>0.05). The bset CNR is in 75 keV’s single spectral image. Conclusion: Spectral CT colonography is efficient in detecting small colonic polyps, the best single spectral images is 75 keV.
2012, Vol. 23 
