Qingguo Wang, Presenter: Nothing to Disclose

Zhiguo Zhou, Abstract Co-Author: Nothing to Disclose

Qimeng Quan MD, PhD, Abstract Co-Author: Nothing to Disclose

Zheng Wang MD, Abstract Co-Author: Nothing to Disclose

Han Wang MD, PhD, Abstract Co-Author: Nothing to Disclose

To evaluate the impact of low-tube-current GSI associated with ASiR on radiation dose and image quality in upper abdominal CTA. 

Twenty-six patients who underwent GSI for upper abdominal CTA using a 64-row CT scanner (GE Discovery CT750 HD) were enrolled. Before confirming GSI scan, GSI assist software allowed optimal mA selected automatically based on the scout view and noise index at 12. Patients were retrospectively divided into two groups. Group A (n=14) and group B (n=12) underwent CT scan with high tube current (≥560mA) and low tube current (＜560mA) respectively. 70keV monochromatic images with a fixed blending level (50%) of ASiR were reconstructed for group B. The SD values of subcutaneous fat were measured. The CT values and contrast noise ratios (CNRs) of aorta (AR) and superior mesenteric artery (SMA) were measured and calculated. The CT dose index volume (CTDIvol) of each patient were recorded. The dose length produce (DLP) was recorded and effective radiation dose was calculated.

The mean CTDIvol and effective radiation dose in group B (11.55 ±2.94mGy, 4.48 ±1.34mSv) were significantly lower than group A (18.13±3.64mGy, 7.56 ±2.68mSv) (p< 0.01). There were not significantly different mean CT values of AR and SMA (219.40±36.85, 194.76±40.44) between group B and group A (239.86±63.15, 217.56±59.25) (p> 0.05). The SD values of subcutaneous fat in group A (5.57±1.10) was lower than group B (7.37±2.03) (p< 0.05). There were not significantly different mean CNRs of AR and SMA between group B (61.66±14.71, 57.21±14.87) and group A (51.57±17.99, 48.17±16.66) (p> 0.05).

Compared with high tube current GSI,approximate 41% radiation dose reduction can be acquired by low-tube-current GSI associated with ASiR without degradation of image quality and noise in abdominal CTA. 

Low-tube-current GSI combined with ASIR has the ability to reduce radiation dose without image quality loss.

Wang, Q, Zhou, Z, Quan, Q, Wang, Z, Wang, H, Feasibility of Low-tube-current Gemstone Spectral Imaging (GSI) Associated with Adaptive Statistical Iterative Reconstruction (ASiR) in Upper Abdominal CT Angiography (CTA) .  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14009180.html