Purpose: Endovascular treatment of stroke, a leading cause of death in the United States, involves guidance of devices to the intervention site often through tortuous vessels. Typically, these interventions are performed under two- dimensional (2D) fluoroscopy. To facilitate these procedures, we developed and previously presented a multiple-view self-calibration method involving two steps: (1) calibration of the imaging geometry, and (2) reconstruction of the 3D vessel centerline. Only those 2D angiograms obtained during the procedure are used for reconstruction. In this manuscript, we evaluate this technique on a large set (117 cases) of clinical data obtained over a 12-month period.
Methods: We evaluated the technique using (1) the RMS difference between the calculated 3D centerlines and the average centerline (before and after application of our method), (2) the difference between the projected 3D centerlines and the 2D indicated centerlines, (3) the translations and rotations calculated by our technique, and (4) intra- and inter-user variations.
Results: Our approach (1) reduces the RMS 3D differences by a factor of 10, (2) increases the number of projected 3D centerline points lying within 1 mm of the indicated 2D centerline points by over a factor of 2 (from 28 to 71%), (3) provides an assessment of the variations in the gantry geometry as provided by the imaging system, and (4) is insensitive to user variations in indication (<1 mm differences in 3D are seen).
Conclusions: These results indicate that this technique will provide more reliable vessel centerlines in the clinical setting without requiring additional acquisitions or increasing dose to the patient.