Optimization of multidetector array CT acquisition parameters for CT colonography.
BACKGROUND
Multidetector array computed tomography technology has increased the number of acquisition parameters that a user must select. This article examines the criteria by which detector collimation, reconstructed scan width, reconstruction scan interval, pitch, image noise, and patient dose can be optimized.


METHODS
A water phantom containing tissue-equivalent polyps in an air-filled tube was scanned using multiple acquisition parameter combinations. X-ray tube current was changed to independently match dose and noise to a single-detector array technique. Images were assessed in axial and three-dimensional formats.


RESULTS
All polyps were visible in axial and three-dimensional images for all scans. Helical artifacts were noted at higher table speed values. The 5-mm-wide scans spaced at 3-mm intervals allowed visualization of the smallest polyps: 5 x 5 or 7 x 3 (diameter x height; mm).


CONCLUSIONS
Our results indicate that thin-scan and low-noise techniques need not be used to visualize polyps of clinically relevant sizes.
McCollough
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Department of Radiology, E2-A, Mayo Clinic and Mayo Foundation, 200 First Street SW, Rochester, MN 55905, USA.
D016477:Artifacts; D003111:Colonic Polyps / Q000000981:diagnostic imaging*; D023881:Colonography, Computed Tomographic / Q000295:instrumentation* / Q000379:methods*; D006801:Humans; D019047:Phantoms, Imaging