The purpose of this study is to analyze how accurate duplex ultrasonography using color Doppler and computed tomography (CT) angiography are in detection of peripheral arterial disease (PAD) in comparison with the Gold Standard of digital subtraction angiography (DSA). This is a single-center prospective, analytical study done on patients with symptoms of PAD referred to the Department of Radiodiagnosis of Medical Trust Hospital (n = 53). All patients were imaged with color Doppler, CT angiography, and DSA. The peak systolic velocity (PSV) ratio was calculated by Doppler ultrasound, and the percentage stenosis for the same vascular segments was calculated using CT angiography and DSA. To test the statistical significance between the results, chi-square test was used. A P value <.05 indicates statistical significance. The PSV ratio for each grade—normal (<1.5), mild (1.5-2.8), moderate (2.9-4.9), and severe (≥5)—and the percentage of stenosis for each grade observed on CT angiography—normal (<20% stenosis), mild (20%-49% stenosis), moderate (50%-74% stenosis), severe (75%-99% stenosis), and total occlusion (100% stenosis)—were found to be highly sensitive and specific with good positive predictive value, negative predictive value, and accuracy level when compared with DSA with narrow confidence intervals for each range. The P value was <.001 for both color Doppler and CT angiography. Computed tomography angiography can be an effective tool as an alternative to DSA for gradation of stenosis if the artifacts resulting from vascular calcification can be avoided. Duplex ultrasonography can be utilized for gradation of stenosis by using the value of PSV ratio and spectral pattern together. However, it can only act as an adjunct to CT angiography because it is incapable of imaging the full length of the arterial segments in 1 frame.
CT-angiography and doppler ultrasound evaluation of congenital portosystemic shunts
