To provide initial assessment of image quality and dose for a cone-beam computed tomographic (CT) scanner dedicated to extremity imaging.A prototype CT has been developed imaging the extremities, including weight-bearing lower extremities. Initial technical included evaluation radiation measured as function kilovolt peak tube output (in milliampere seconds), contrast resolution assessed in terms signal difference-to-noise ratio (SDNR), spatial semiquantitatively by using line-pair module...

Purpose: This paper reports on the design and initial imaging performance of a dedicated cone‐beam CT (CBCT) system for musculoskeletal (MSK) extremities. The complements conventional MR offers variety potential clinical logistical advantages that are likely to be benefit diagnosis, treatment planning, assessment therapy response in MSK radiology, orthopaedic surgery, rheumatology. Methods: scanner incorporated host requirements (e.g., ability scan weight‐bearing knee natural stance) was...

Purpose: A flat‐panel detector based mobile isocentric C‐arm for cone‐beam CT (CBCT) has been developed to allow intraoperative 3D imaging with sub‐millimeter spatial resolution and soft‐tissue visibility. Image quality radiation dose were evaluated in spinal surgery, commonly relying on lower‐performance image intensifier C‐arms. Scan protocols task‐specific at minimum dose, in‐room exposure was evaluated, integration of the system a surgical guidance demonstrated preclinical studies...

Purpose: Design and optimization of medical imaging systems benefit from accurate theoretical modeling that identifies the physical factors governing image quality, particularly in early stages system development. This work extends Fourier metrics performance detectability index to tomosynthesis cone‐beam CT (CBCT) investigates extent which is a valid descriptor task‐based as assessed by human observers. Methods: The for tasks presented 2D slices was derived 3D cascaded analysis CBCT....

Purpose: The proliferation of cone‐beam CT (CBCT) has created interest in performance optimization, with x‐ray scatter identified among the main limitations to image quality. CBCT often contends elevated scatter, but wide variety imaging geometry different configurations suggests that not all are affected same extent. Graphics processing unit (GPU) accelerated Monte Carlo (MC) simulations employed over a range geometries elucidate factors governing characteristics, efficacy antiscatter...

Traditional space-invariant regularization methods in tomographic image reconstruction using penalized-likelihood estimators produce images with nonuniform spatial resolution properties. The local point spread functions that quantify the smoothing properties of such are space variant, asymmetric, and object-dependent even for invariant imaging systems. authors propose a new quadratic scheme systems yields increased uniformity is motivated by least-squares fitting parameterized impulse...

Purpose: Nonstationarity is an important aspect of imaging performance in CT and cone‐beam (CBCT), especially for systems employing iterative reconstruction. This work presents a theoretical framework both filtered‐backprojection (FBP) penalized‐likelihood (PL) reconstruction that includes explicit descriptions nonstationary noise, spatial resolution, task‐based detectability index. Potential utility the model was demonstrated optimal selection regularization parameters PL Methods:...

Purpose: A method of intensity‐based deformable registration CT and cone‐beam (CBCT) images is described, in which intensity correction occurs simultaneously within the iterative process. The preserves speed simplicity popular Demons algorithm while providing robustness accuracy presence large mismatch between CBCT voxel values (“intensity”). Methods: variant was developed an estimate relationship for specific materials image computed at each iteration based on set currently overlapping...

We present a framework for robustly estimating registration between 3D volume image and 2D projection evaluate its precision robustness in spine interventions vertebral localization the presence of anatomical deformation. The employs normalized gradient information similarity metric multi-start covariance matrix adaptation evolution strategy optimization with local-restarts, which provided improved against deformation content mismatch. parallelized implementation allowed orders-of-magnitude...

CT is the frontline imaging modality for diagnosis of acute traumatic brain injury (TBI), involving detection fresh blood in (contrast 30-50 HU, detail size down to 1 mm) a non-contrast-enhanced exam. A dedicated point-of-care system based on cone-beam (CBCT) could benefit early TBI and improve direction appropriate therapy. However, flat-panel detector (FPD) CBCT challenged by artifacts that degrade contrast resolution limit application soft-tissue imaging. We present evaluate fairly...

Robotic C-arms are capable of complex orbits that can increase field view, reduce artifacts, improve image quality, and/or dose; however, it be challenging to obtain accurate, reproducible geometric calibration required for reconstruction such orbits. This work presents a method an arbitrary source-detector orbit by registering 2D projection data previously acquired 3D image. It also yields which simple circular improved. The registration uses normalized gradient information similarity...

Cone-beam CT (CBCT) for musculoskeletal imaging would benefit from a method to reduce the effects of involuntary patient motion. In particular, continuing improvement in spatial resolution CBCT may enable tasks such as quantitative assessment bone microarchitecture (0.1 mm–0.2 mm detail size), where even subtle, sub-mm motion blur might be detrimental. We propose purely image based compensation that requires no fiducials, tracking hardware or prior images. A statistical optimization...

Imaging systems that form estimates using a statistical approach generally yield images with nonuniform resolution properties. That is, the reconstructed possess properties marked by space-variant and/or anisotropic responses. We have previously developed penalty for penalized-likelihood (PL) reconstruction yields nearly uniform . demonstrated how to calculate this efficiently and apply it an idealized positron emission tomography (PET) system whose geometric response is space-invariant. In...

Surgical targeting of the incorrect vertebral level ("wrong-level" surgery) is among more common wrong-site surgical errors, attributed primarily to a lack uniquely identifiable radiographic landmarks in mid-thoracic spine.Conventional localization method involves manual counting bodies under fluoroscopy, prone human error, and carries additional time dose.We propose an image registration visualization system (referred as LevelCheck), for decision support spine surgery by automatically...

The likelihood of finding manufactured components (surgical tools, implants, etc.) within a tomographic field-of-view has been steadily increasing. One reason is the aging population and proliferation prosthetic devices, such that more people undergoing diagnostic imaging have existing particularly hip knee implants. Another use intraoperative (e.g., cone-beam CT) for surgical guidance increasing, wherein tools devices as screws plates are placed or near to target anatomy. When these contain...

The potential for statistical image reconstruction methods such as penalized-likelihood (PL) to improve C-arm cone-beam CT (CBCT) soft-tissue visualization intraoperative imaging over conventional filtered backprojection (FBP) is assessed in this work by making a fair comparison relation performance. A prototype mobile was used scan anthropomorphic head and abdomen phantoms well cadaveric torso at doses substantially lower than typical values diagnostic CT, the effects of dose reduction via...

Purpose: A deformable registration method capable of accounting for missing tissue (e.g., excision) is reported application in cone‐beam CT (CBCT)‐guided surgical procedures. Excisions are identified by a segmentation step performed simultaneous to the process. Tissue excision explicitly modeled increasing dimensionality deformation field allow motion beyond image. The accuracy model tested phantom, simulations, and cadaver models. Methods: variant Demons algorithm modified include modeling....

Over the course of diagnosis and treatment, it is common for a number imaging studies to be acquired. Such sequences can provide substantial patient-specific prior knowledge about anatomy that incorporated into prior-image-based tomographic reconstruction improved image quality better dose utilization. We present general methodology using model-based approach including formulations measurement noise also integrates images. This penalized-likelihood technique adopts sparsity enforcing penalty...

Purpose: Photon counting detectors (PCDs) are an emerging technology with applications in spectral and low‐dose radiographic tomographic imaging. This paper develops analytical model of PCD imaging performance, including the system gain, modulation transfer function (MTF), noise‐power spectrum (NPS), detective quantum efficiency (DQE). Methods: A cascaded systems analysis describing propagation quanta through chain was developed. The validated comparison to physical performance a...

While model-based reconstruction methods have been successfully applied to flat-panel cone-beam CT (FP-CBCT) systems, typical implementations ignore both spatial correlations in the projection data as well system blurs due detector and focal spot x-ray source. In this work, we develop a forward model for flat-panel-based systems that includes blur noise correlation associated with finite size an indirect (e.g., scintillator). This is used staged framework where are deconvolved...

We develop a mathematical framework for the design of orbital trajectories that are optimal to particular imaging task (or tasks) in advanced cone-beam computed tomography systems have capability general source–detector positioning. The allows various parameterizations orbit as well constraints based on system capabilities. To accommodate nonstandard geometries, model-based iterative reconstruction method is applied. Such algorithms generally complicate assessment and prediction...

Gibbon, John H. Jr. M.D.; Allbritten, Frank F. Stayman, Joseph W. Judd, James M. M.D. Author Information