Clinical Application Of Dual-energy Different Scanning Mode In CT Pulmonary Angiography

ObjectiveTo compare dose and image quality of first generation dual-energy CT (DECT)and flash dual-energy CT for CT pulmonary angiography (CTPA); evaluate the consistency between perfusion images and CTPA images.Materials and Methods120patients (72male,48female; age range,22～77years; average age,59.12±9.54years) that were clinically suspected pulmonary embolism were randomly divided into4groups with30cases in each group and underwent CTPA on a first generation (A:DE,140/80kV) or flash dual-source DECT device (B:DE,100/Sn140kV; C:DE,80/Sn140kV; D:DE,140/80kV).The scan range was from lung apex to the phrenic top level and direction is from head side to the foot side. Unenhanced scan was completed firstly and then direct enhanced dual-energy scanning with an injection flow rate of4.0ml/s, followed by a saline chaser of50ml respectively. The region of interest (ROI) of triggering position located of pulmonary trunk. CTDIvol, DLP, background noise (BN) and SNR of the pulmonary artery were compared.Image quality of Pulmonary arteries was analyzed two radiologists with double blind method. Perfusion blood volume(PBV)images was obtained after post-processing of the raw data. Observers analysis the location of perfusion detect and compare with the CTPA images.Results Thorax diameter and attenuation in the pulmonary trunk did not differ significantly (p>0.05) between the groups. Mean CTDIvol and DLP were significantly lower (p<0.05) in group B(4.46±1.20mGy/138.76±39.53mGycm) compared to group A(6.44±1.46mGy/200.44±47.34mGycm), group C(6.66±2.20mGy/200.44±60.58mGycm)and groupD(5.33±1.00mGy/159.16±24.215mGycm). BN was significantly lower (p<0.05) in group B (8.92±2.46HU) and group D(8.83±3.31HU) compared to group Aand C (10.58±2.20HUand9.59±3.38).SNR of pulmonary in group B(23.17±10.8,27.78±12.49) is better than group D (16.81±8.58,19.40±10.16).The location of perfusion detect was similar to the location of embolus in pulmonary artery.ConclusionThe use of flash dual-energy CT in80/Sn140kV configuration allows for significant dose reduction with image quality similar to other groups.The consistency between perfusion images and CTPA images is good.