Purpose: To compare radiation dose and image quality
in regular, low, and ultralow-dose CT protocols, and to
evaluate diagnostic performance of low-dose CT for
urolithiasis.
Materials and methods: Sixty-five patients with suspected
urolithiasis underwent three different scans under the
regular, low, and ultralow-dose protocols. The regular
dose scans were reconstructed using filtered back projection
and the low-dose scans were reconstructed using a
statistical iterative reconstruction. The ultralow-dose
scans were reconstructed using both techniques in
addition to a knowledge-based IR. Effective radiation
doses were compared. Objective image noise was assessed
by measuring standard deviation of HU and subjective
image assessment was performed with a 3- or 5-point
scale. Diagnostic performance of the low-dose image was
evaluated, using the regular dose image as a standard
reference and the interobserver agreement between two
reviewers with different levels of experience was calculated.
Results: The effective radiation dose was significantly
different in each protocol (p < 0.001) and estimated
dose reduction of the low-dose and ultralow-dose