Yan Liang MMed, Abstract Co-Author: Nothing to Disclose

Zhiren Chen MD, Presenter: Nothing to Disclose

Dongbin Shi, Abstract Co-Author: Nothing to Disclose

Yan Wang, Abstract Co-Author: Nothing to Disclose

Bin Li, Abstract Co-Author: Nothing to Disclose

Huizhi Cao, Abstract Co-Author: Nothing to Disclose

Ying Tong, Abstract Co-Author: Nothing to Disclose

To explore the optimal protocol of CT scanning mode in the portal vein angiography with a low-concentration contrast medium.

63 patients underwent enhanced urinary CT scan All the patients were divided into 3 groups according to different body mass index(BMI). 21 patients of group A(BMI≤22) received 80-100kVp CT scan, automatic exposure control (3D Auto mA) and pitch of 0.984. All the images were reconstructed with adaptive statistical iterative reconstruction algorithm. 14 patients of group B (BMI≥26) received single-source dual-energy spectral CT (sDECT)scan at the pitch of 1.375. Monochromatic images was reconstructed and optimal keV with best contrast-to-noise(CNR) was calculated. Another 28 patients of group C with routine 120 kVp CT scan. Low concentration of iodixanol(270mg I/ml) was used in group A and B, and high concentration of iopamidol(370 mg I/ml) was adopted in group C. 70 ml of total amount of contrast was injected at 2.7ml/s. ROIs were placed on abdominal aorta, renal artery, superior mesenteric artery and portal vein. Signal-to-noise ratio (SNR) and CNR was calculated.

In low-kVp Group, the CNR and SNR were (8.12±3.09) and (14.72±4.05) for trunk of portal vein, (6.59±2.13) and (13.40±4.68) for its left branch, and (7.24±2.19) and (13.56±4.99) for its right branch respectively. In sDECT Group, the CNR and SNR were (8.68±2.69) and (13.38±3.06) for trunk of portal vein, (9.31±2.88) and (13.58±3.21) for its left branch, and (9.53±2.66) and (13.72±3.03) for its right branch respectively. In 120kVp Group, the CNR and SNR were (6.68±3.41) and (13.13±4.36) for trunk of portal vein, (6.22±1.98) and (12.82±4.11) for its left branch, and (7.09±2.04) and (12.55±4.36) for its right branch respectively. The image quality was slightly higher in sDECT Group than routine 120kVp Group and low-kVp Group, but no significantly  different was found in among three groups (P>0.05). Compared with that in 120kVp Group (7.23±1.53mGy), the radiation dose index was significantly lower in low-kVp Group (4.75±1.39 mGy) (P<0.05), and was higher in sDECT group (15.64mGy).

With a low-concentration contrast medium, the low-kVp and sDECT scanning mode is rationally via BMI without sacrificing image quality.

With low kVp and spectral CT imaging of low iodine concentration or 120kVp of moderate iodine concentration, higher intravascular enhancement can be achieved with good vessel display.

Liang, Y, Chen, Z, Shi, D, Wang, Y, Li, B, Cao, H, Tong, Y, Optimal Protocol of Scanning Mode in the Portal Vein Angiography with a Low-Concentration Contrast Medium.  Radiological Society of North America 2013 Scientific Assembly and Annual Meeting, December 1 - December 6, 2013 ,Chicago IL. http://archive.rsna.org/2013/13025890.html