No abstract

Altogether, these results demonstrate the potential of the robotic scanner to adequately represent lower limb vessels for the clinical evaluation of stenoses.

No abstract

Stenosis degree is the most common criterion used to assess the severity of atherosclerosis. This form of peripheral arterial disease (PAD) is often present in lower limb arteries. However, to detect and quantify distributed arterial stenoses in lower limbs, a high precision is required over a long segment. Moreover, to plan the appropriate therapy, a 3D representation of the vessel is desirable. Most 3D-ultrasound (US) developments are not optimally adapted for this application. A new 3D-US imaging robotic system that can control and standardize the 3D-US acquisition process for any scanning distance is presented. A calibration study is performed to determine the spatial transform to relate the US probe image plane attached to the robotic system, to the robot coordinates. Additionally, 3D-US reconstructions of in-vitro stenoses were obtained with the robotic scanner and the spatial calibration transform computed. Thereafter, stenoses were detected and quantified from the 3D reconstructed model. Altogether, these results demonstrate the potential of the robot for the clinical evaluation of lower limb vessels over long and tortuous segments starting from the iliac artery down to the popliteal artery below the knee.

The localization of lesions, their lengths and the degree of stenosis are the most common criteria used to assess the severity of lower limb peripheral arterial disease (PAD). 2D-ultrasound (US) imaging is the first-line diagnosis method used to investigate arterial lesions; however, it cannot render a 3D map of the entire lower limb vascular tree required for therapy planning. Moreover, current 3D-US developments are not optimally adapted for this particular clinical application. We proposed a prototype 3D-US imaging robotic system that can control and standardize the image acquisition process to reconstruct accurately arteries from the iliac down to the popliteal. Because calibration has a major impact on the quality of reconstructed geometries, a customized Z-phantom calibration procedure was first implemented. At optimum US settings, the calibration transform was evaluated with a reconstruction precision < 1.10 mm. The calibration transform accuracy was also evaluated on two vascular phantoms of lower limb mimicking vessel geometries. Reconstruction performances were assessed in distance errors and cross-sectional areas. The mean reconstruction distance error was 0.39 ± 0.35 mm for the axisymmetric cylindrical phantom, whereas it was 1.38 ± 1.29 mm for the realistic reproduction of a diseased iliac artery. Similar findings were found for the area measures. Altogether, these results demonstrate the potential of the robot to represent adequately lower limb vessels for the clinical evaluation of stenoses.