| Objective To investigate the value of spectral CT optimal single energy image in improving image quality of lower extremity angiography.Methods Thirty-four patients suspected with lower extremity atherosclerotic occlusive diseases (LEAOD) according with inclusive criteria were prospectively selected and randomly divided into research group and control group. Research group (17 cases) were scanned with gemstone spectral CT and control group (17 cases) were scanned with 64-slice spiral CT. Optimal single energy image was calculated by post-processing software in research group, CT value and background noise value in the middle plane of iliac artery, femoral artery, popliteal artery and pretibial artery were measured in two groups and contrast noise ratio (CNR) was calculated to evaluated the image quality objectively. The images were evaluated independently by 2 professional physicians based on a 5-level evaluation standard.Results The optimal single energy located between fifty-eight and sixty-seven KeV. The CT values and CNR of iliac artery, femoral artery, popliteal artery and pretibial artery in research group were all higher than that in control group. Among them, the CT values respectively increased by 17.6%,12.2%,12.3% and 35.2%, the differences were statistically significant (t= 2.818,1.636, 1.119,1.636, P< 0.01). The CNR respectively increased by 44.3%,40.8%,59.5%,105.8%, the differences were statistically significant (t= 3.729,4.686,4.294,4.686, P< 0.01). The image scores of two groups accessed by two physicians were respectively 82:69 and 81:68, the differences of two groups were statistically significant (P<0.01).Conclusion In lower extremity CT angiography, spectral CT optimal single energy image is more excellent than 64-slice spiral CT in detecting narrow blood vessels, distal small blood vessels and removing hardening artifacts, which could providing important guiding significance for preoperative and postoperative assessment of lower extremity endovascular angioplasty. |
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