Urinary calculi: improved detection and characterization with thin-slice multidetector CT

The aim of this study was to assess the effect of reconstructed slice thickness on the detection and characterization of human urinary calculi on a multidetector helical CT scanner. Nineteen human urinary calculi of various chemical composition measuring 1.0-3.7 mm were embedded into agar in a chamber of a nylon body phantom. The phantom was imaged with a four detector-row CT scanner. The number of detected calculi increased as the reconstructed slice thickness decreased. Measured diameters and density of the visible calculi decreased as the slice thickness increased. The results of the present study support the use of thin reconstructed slices to detect and characterize urinary calculi.