Articles: surgery.
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The two-dimensional (2D)-three dimensional (3D) registration of a computed tomography image to one or more x-ray projection images has a number of image-guided therapy applications. In general, fiducial marker-based methods are fast, accurate, and robust, but marker implantation is not always possible, often is considered too invasive to be clinically acceptable, and entails risk. There also is the unresolved issue of whether it is acceptable to leave markers permanently implanted. Intensity-based registration methods do not require the use of markers and can be automated because such geometric features as points and surfaces do not need to be segmented from the images. However, for spine images, intensity-based methods are susceptible to local optima in the cost function and thus need initial transformations that are close to the correct transformation. ⋯ The use of one fiducial marker reduces 2D-3D spine image registration error slightly and improves robustness substantially. The findings are potentially relevant for image-guided therapy. If one marker is sufficient to obtain clinically acceptable registration accuracy and robustness, as the preliminary results using the proposed hybrid similarity measure suggest, the marker can be placed on a spinous process, which could be accomplished without penetrating muscle or using fluoroscopic guidance, and such a marker could be removed relatively easily.
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Stud Health Technol Inform · Jan 2005
First clinical tests with the augmented reality system INPRES.
In this paper we present the results of the first patient experiment in craniofacial surgery of the INPRES system - an augmented reality system on the basis of a tracked see-through head-mounted display.
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Comput. Aided Surg. · Jan 2005
Measurements of acetabular cup position and pelvic spatial orientation after total hip arthroplasty using computed tomography/radiography matching.
This study presents a clinical validation of postoperative measurements of acetabular cup alignment following total hip arthroplasty (THA). The methodology was based on concurrent anatomic three-dimensional (3D) measurements of both the acetabular cup alignment and pelvic orientation, using an original CT/X-ray matching algorithm named Xalign. The subjects were 19 patients who had undergone bilateral THA using CT-based surgical navigation. ⋯ The mean cup abduction error was 0.85 degrees +/- 1.3 degrees (+/- standard deviation) and the mean version error was 0.01 degrees +/- 1.99 degrees. Conventionally measured cup abduction ranged from 44 degrees to 62 degrees and correlated significantly (p = 0.001, r = -0.5) with pelvic flexion angle, proving the linear negative correlation between pelvic flexion and the error in conventional radiographic cup measurements. The Xalign method offered reasonable accuracy for cup orientation, and allowed cup and pelvic 3D anatomic measurements at different times.
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Case Reports
Image-guided surgery in resection of benign cervicothoracic spinal tumors: a report of two cases.
Osseous spinal tumors are an uncommon cause of persistent axial pain and muscle spasm, but even benign lesions may grow to cause deformity or neurological signs. Traditional treatment approaches to resection can be debilitating even when the tumor is benign. ⋯ Image guidance can accurately localize and guide excision of benign vertebral lesions while minimizing soft tissue trauma and collateral damage, allowing patients a rapid and complete return to high-demand function.
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While both fluoroscopic and CT-guidance during cervical nerve root blocks have been well documented in the literature, the use of CT fluoroscopy (CTF) has not. CTF is well suited to provide imaging guidance during these procedures due to its combination of excellent anatomic detail, relatively low radiation dose and the ability to perform an initial dynamic contrast injection, and is a viable alternative to fluoroscopic guidance. Details of the technique along with the initial experience at one institution are presented.