Chuang Yi, Abstract Co-Author: Research Grant, General Electric Company

Zhiren Chen MD, Abstract Co-Author: Nothing to Disclose

Yan Liang MMed, Presenter: Nothing to Disclose

Bin 00617875. Li, Abstract Co-Author: Nothing to Disclose

Yongfang Yin, Abstract Co-Author: Nothing to Disclose

Dongbin Shi, Abstract Co-Author: Nothing to Disclose

To explore the impact of different helical pitch onspectral CT imaging in the urinary CT examination.

Among 54 cases of urinary CT examination, 23 and 31 cases underwent single-source dual-energy CT (sDECT) at a helical pitch of 1.375:1 and 0.984:1, respectively.Monochromatic images of 65keV were reconstructed, and the image noise of renal parenchyma was evaluated. Signal-to-noise ratio (SNR) and contrast-noise-ratio(CNR) was calculated with ROI measurements. The figure of merit (FOM), calculated as CNR(2)/CTDI(vol), was used to quantify image quality improvement per exposure risk.

For 1.375 Group and 0.984 Group, the CNR of image was not significantly different (P>0.05) (2.45±0.70 Vs2.48±0.68 ), and SNR was (4.34±1.24) and (4.57±1.20) respectively. Compared with that in 0.984 Group (25.53mGy), the CTDI was significantly lower in1.375 Group (18.28mGy). FOM of 1.375 (0.33) was higher than 0.984 Group ( 0.24), increased by 38% .  

Conclusion: At a high scanning helical pitch of spectral CT imaging, the radiation dose is significantly lower, but the image noise is not significantly different. Therefore, the urinary system CT examination could be scanned at a large pitch.

Spectral CT imaging is always associated with a high radiation dose, and high pitch protocol could increase the efficiency of radiation dose without sacrificing image quality.  

Yi, C, Chen, Z, Liang, Y, Li, B, Yin, Y, Shi, D, Impact of Different Helical Pitch Selection on Spectral CT Imaging: Comparison of Image Quality and Radiation Dose .  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14045649.html