Three-dimensional reconstruction of the femoral artery bifurcation with noninvasive B-mode ultrasound and a new position registration device

B-mode ultrasound (BMUS) and conventional arteriography provide information concerning arterial geometry and patency in a two-dimensional (2- D) format. It is now possible to reconstruct three-dimensional (3-D) arterial images from 2-D BMUS data. The purpose of this project is to relate experience with 3-D reconstruction of the femoral artery bifurcation in ten normal volunteers and three patients with arterial disease using BMUS and a novel, linear-restraint position registration device (PRD). This simple device allows linear movement of the BMUS transducer in a single, fixed line (the z-axis) while keeping constant the orientation of the imaging plane (the x- and y-axes). BMUS examination of the relatively straight femoral artery bifurcation is thus accomplished by moving the transducer along the straight line defined by the PRD. The resultant BMUS transducer position coordinates are recorded and superimposed on video output by an image processing computer, then are digitized and processed on a dedicated 3-D reconstruction workstation. Intimal and adventitial boundaries are created using manual boundary definition techniques. Reformatting into 3-D images is accomplished by assigning 2-D picture elements (pixels) an arbitrary thickness of 1 mm. The resultant volume elements (voxels) are displayed in a 3-D matrix. 'Stacking' of the processed images aligns the voxel matrix into an actual 3- D arterial image. Any disease process can be localized and plaque volume defined. Normal subjects were imaged to assess qualitative validity of the technique. Patients with suspected femoral artery disease were 'reconstructed' to define any arterial wall pathology. All three patient BMUS reconstructions correlated well with angiographic pathology in a blinded fashion. This method of 3-D BMUS reconstruction is feasible, reveals adequate detail of arterial lumen and wall geometry, defines plaque volume, and correlates well with conventional angiography. Potential clinical usefulness of 3-D reconstruction includes the noninvasive monitoring of atherosclerotic progression or regression for postoperative follow-up or for diagnosis where conventional angiography is contraindicated or technically unsafe.