To explore the application value of spectral detector CT virtual non-contrast in CTU of urinary calculi.

Clinical datas of fifty patients with urinary calculi were retrospectively analyzed. All patients completed the examination according to the routine procedure, and then get the VNC images by the workstation. Virtual plain scan and conventional enhanced images were divided into a group, real plain scan and conventional enhanced images were divided into the control group. Then the CT values and signal-to-noise ratio (SNR) of renal cortex and abdominal aorta of two groups were compared. Finally, two senior diagnosises evaluated the quality of the images and calculated the stone detection rate.

There was no significant difference in image quality and the detection rate of stone between VNC and real plain scan, and the images can be satisfied for the requirement of diagnosis. The average score of the virtual plain scan group was 3.7, and the average score of the real plain scan group was 4.0. The average CT value of the region of interest (ROI) was slightly higher than the average of the ROI of the real plain scan, and the SNR of the ROI of virtual plain scan was also higher than that of real plain scan (P<0.05). In terms of the detection rate of stones, the detection rate of stones under 2 mm in the virtual plain scan group was consistent with that of the real plain scan group, and the detection rate of stones under 2 mm in the virtual plain scan group reached 87% as in the real plain scan group. If virtual plain scan was instead of real plain scan, the effective radiation dose received by patients can be reduced nearly 25%, about 7.8 mSv.

Spectral CT virtual plain scan has high application value in CTU, the image quality is high, and it can reduce the radiation dose for patients.