Task-driven source–detector trajectories in cone-beam computed tomography: II. Application to neuroradiology

Abstract

We apply the methodology detailed in "Task-driven source-detector trajectories in cone-beam computed tomography: I. Theory and methods" by Stayman et al. for task-driven optimization of source-detector orbits in cone-beam computed tomography (CBCT) to scenarios emulating imaging tasks in interventional neuroradiology. The task-driven imaging framework is used to optimize the CBCT source-detector trajectory by maximizing the detectability index, d 0. The approach was applied to simulated cases of endovascular embolization of an aneurysm and arteriovenous malformation and was translated to real data first using a CBCT test bench followed by implementation on an interventional robotic C-arm. Task-driven trajectories were found to generally favor higher fidelity (i.e., less noisy) views, with an average increase in d 0 ranging from 7% to 28%. Visually, this resulted in improved conspicuity of particular stimuli by reducing the noise and altering the noise correlation to a form distinct from the spatial frequencies associated with the imaging task. The improvements in detectability and the demonstration of the task-driven workflow using a real interventional imaging system show the potential of the task-driven imaging framework to improve imaging performance on motorized, multiaxis C-arms in neuroradiology.

Optimization for customized trajectories in cone beam computed tomography

“…objectivef unction ¼ FSIM (11) arc optimal ¼ arc max objectivefunction ð Þ ¼ arc max FSIM ð Þ (12) In addition to FWHM avg and FSIM, the two other image quality metrics, including universal quality index (UQI) and contrast-to-noise ratio (CNR), were used in order to evaluate the final real-data reconstructed image:…”

“…Noncircular source-detector trajectories are suggested in using periodic and B-spline base functions in simulation studies as well as in the neuroradiology application. 11,12 An increased performance in a volume of interest (VOI) over standard orbits was the result of these studies. [8][9][10][11][12] Our work aims at facilitating the design of patient-specific limited angle trajectories for a dedicated VOI, which takes kinematic constraints into account.…”

“…11,12 An increased performance in a volume of interest (VOI) over standard orbits was the result of these studies. [8][9][10][11][12] Our work aims at facilitating the design of patient-specific limited angle trajectories for a dedicated VOI, which takes kinematic constraints into account. As a result, highly compact imaging units allowing for a variety of intra-interventional image update tasks for image-guided radiotherapy, computeraided surgery, and interventional radiology are facilitated.…”

“…Usually hard constraints on the rotation angle were used to avoid collision limits. 8,9,11,12 Our approach enhances those earlier efforts by optimizing a sequence of arbitrary short scan trajectories, including rotations in cranio/caudal direction, with a technique similar to dose planning in volume-modulated arc therapy or other advanced radiotherapy method. Instead of optimizing dose in the target volume and organ sparing like in radiotherapy, we use a numerical simulation of potential trajectories, which optimizes image quality based on prior tomographic data by means of finding optimal 3D orientation for reconstructing a given VOI.…”

Short Scan Source-detector Trajectories for Target-based CBCT

“…In [3], the authors examined the integration of prior 3D imaging data for developing customized trajectories using a greedy approach as the trajectory optimization method. Non-circular trajectories are proposed in [4] using B-spline and periodic base functions in simulation experiments as well as in the neuroradiology [5]. Their proposed task-driven trajectories [3][4][5] could increase the reconstruction performance for a variety of imaging tasks.…”