Detectability of small and flat polyps in MDCT colonography using 2D and 3D imaging tools: results from a phantom study

OBJECTIVE. The objective of this phantom study was to determine the performance of MDCT colonography for the detection of small polyps under ideal imaging conditions and to determine the added value of 3D imaging when used as an adjunct to 2D imaging.MATERIALS AND METHODS. Thirty-six polypoid and 39 flat polyps (44 lesions, 2-5 mm; 31 lesions, 6-8 mm) were placed in three explanted segments of a thoroughly cleaned porcine colon (overall length, 4.5 m) that was distended with air and submerged in a water phantom. MDCT data sets with 4 × 1 mm collimation and 6-mm table feed were reconstructed every 0.7 mm with 1.25-mm effective slice width. The data were reviewed by three radiologists using 2D images in all three projections and with 3D volume-rendered images available as an adjunct to the 2D images.RESULTS. Additional 3D as a problem-solving tool significantly increased the overall sensitivity (96% vs 90%), decreased the total number of false-positive calls (n = 9 vs n = 5), and increased the diagnostic co...