Chen Xiaoxia MMed, Presenter: Nothing to Disclose

Lei Yuxin MMed, Abstract Co-Author: Nothing to Disclose

Tian Qian MMed, Abstract Co-Author: Nothing to Disclose

Jia Yongjun MMed, Abstract Co-Author: Nothing to Disclose

Tian Xin MMed, Abstract Co-Author: Nothing to Disclose

To evaluate the feasibility of routinizing spectral CT in abdominal application with individualized scan protocol by comparing image noise and radiation dose of conventional 120kVp scans.

 Prospectively randomized 39 patients (BMI: 23.08±3.58) who require contrast-enhanced CT scans in the abdomen to 2 groups: group 1 (n=20) with 120kVp for the plain phase and spectral CT for the enhanced portal venous phase (VP); group 2 (n=19) with spectral CT for plain phase and 120kVp for VP. For the 120kVp scan, the tube current (m A) was automatically adjusted to achieve noise index (NI) of 10, and for spectral CT, a m A was selected based on the average of the min and max m A from the 120kVp m A table for NI=10. Scan ranges were 250mm for both groups. CT dose index (CTDI) and effective dose was recorded. Images of 5mm thickness were reconstructed with 50%ASIR in both groups. Image standard deviation (SD) for the liver parenchyma, erector spinae, fat and portal vein on the conventional 120kVp polychromatic images and 70keV monochromatic images from spectral CT was measured and compared with t-test.

 The CTDI and effective dose were (13.32±1.19mGy and 6.19±0.55mSv) for spectral CT, about 10% lower than the respective value of (14.35±4.66mGy and 6.68±2.17mSv) for the 120kVp CT. The SD values (in HU) in the spectral CT images were 5.01±0.48, 4.93±0.77, 5.16±0.93 and 5.81±1.14 for the liver parenchyma, erector spinae, fat and portal vein, respectively. These values were statistically lower than the respective values of 6.69±0.85, 6.05±1.86, 5.74±1.09 and 7.44±1.31 in the conventional 120kVp images (p<0.01).

With individualized scan protocol, spectral CT provides monochromatic images with lower image noise at the same or lower radiation dose in comparison with the conventional 120kVp scans. The lower dose scan protocol makes it feasible to routinize spectral CT in abdominal applications.  

Spectral CT with individualized low dose scan protocol can be routinely used in abdominal applications.

Xiaoxia, C, Yuxin, L, Qian, T, Yongjun, J, Xin, T, Clinical Routinization of Spectral CT with Individualized Scan Protocol in Abdomen: Image Quality and Radiation Dosage Comparison with Conventional 120kVp Scans.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14012332.html