Can NaF PET/CT bone scans help when deciding if early intervention is needed in patients being treated with a TSF attached to the tibia: insights from 41 patients.

Purpose: To demonstrate the usefulness of positron emission tomography (PET)/computed tomography (CT) bone scans for gaining insight into healing bone status earlier than CT or X-ray alone.

Methods: Forty-one prospective patients being treated with a Taylor Spatial Frame were recruited. We registered data obtained from successive static CT scans for each patient, to align the broken bone.

Accuracy and precision of a CT method for assessing migration in shoulder arthroplasty: an experimental study.

Background: Radiostereometric analysis (RSA) is the gold standard to measure early implant migration which is a predictive factor for implant survival.

Purpose: To validate an alternative computed tomography (CT) technique to measure implant migration in shoulder arthroplasty.

Material And Methods: A cadaver proximal humerus and a scapula, which had tantalum beads incorporated within them, were prepared to accept a short-stemmed humeral component and a two-pegged glenoid component of a commercial total shoulder arthroplasty (TSA) system.

Motion Analysis in Lumbar Spinal Stenosis With Degenerative Spondylolisthesis: A Feasibility Study of the 3DCT Technique Comparing Laminectomy Versus Bilateral Laminotomy.

Study Design: This was a randomized radiologic biomechanical pilot study in vivo.

Objective: The objectives of this study was to evaluate if 3-dimensional computed tomography is a feasible tool in motion analyses of the lumbar spine and to study if preservation of segmental midline structures offers less postoperative instability compared with central decompression in patients with lumbar spinal stenosis with degenerative spondylolisthesis.

Summary Of Background Data: The role of segmental instability after decompression is controversial.

Prosthetic liner wear in total hip replacement: a longitudinal 13-year study with computed tomography.

This case report follows a woman who had a total hip replacement in 1992 when she was 45 years old. Six serial computed tomography (CT) examinations over a period of 13 years provided information that allowed her revision surgery to be limited to liner replacement as opposed to replacement of the entire prosthesis. Additionally, they provided data that ruled out the presence of osteolysis and indeed none was found at surgery.

Are CT Scans a Satisfactory Substitute for the Follow-Up of RSA Migration Studies of Uncemented Cups? A Comparison of RSA Double Examinations and CT Datasets of 46 Total Hip Arthroplasties.

As part of the 14-year follow-up of a prospectively randomized radiostereometry (RSA) study on uncemented cup fixation, two pairs of stereo radiographs and a CT scan of 46 hips were compared. Tantalum beads, inserted during the primary operation, were detected in the CT volume and the stereo radiographs and used to produce datasets of 3D coordinates. The limit of agreement between the combined CT and RSA datasets was calculated in the same way as the precision of the double RSA examination.

Can Spatiotemporal Fluoride (F) Uptake be Used to Assess Bone Formation in the Tibia? A Longitudinal Study Using PET/CT.

Background: When a bone is broken for any reason, it is important for the orthopaedic surgeon to know how bone healing is progressing. There has been resurgence in the use of the fluoride (F) ion to evaluate various bone conditions. This has been made possible by availability of positron emission tomography (PET)/CT hybrid scanners together with cyclotrons.

Accuracy and Precision of Three-Dimensional Low Dose CT Compared to Standard RSA in Acetabular Cups: An Experimental Study.

Background and Purpose. The gold standard for detection of implant wear and migration is currently radiostereometry (RSA). The purpose of this study is to compare a three-dimensional computed tomography technique (3D CT) to standard RSA as an alternative technique for measuring migration of acetabular cups in total hip arthroplasty.

A CT method for following patients with both prosthetic replacement and implanted tantalum beads: preliminary analysis with a pelvic model and in seven patients.

Background: Radiostereometric analysis (RSA) is often used for evaluating implanted devices over time. Following patients who have had tantalum beads implanted as markers in conjunction with joint replacements is important for longitudinal evaluation of these patients and for those with similar implants. As doing traditional RSA imaging is exacting and limited to specialized centers, it is important to consider alternative techniques for this ongoing evaluation.

A New CT Method for Assessing 3D Movements in Lumbar Facet Joints and Vertebrae in Patients before and after TDR.

This study describes a 3D-CT method for analyzing facet joint motion and vertebral rotation in the lumbar spine after TDR. Ten patients were examined before and then three years after surgery, each time with two CT scans: provoked flexion and provoked extension. After 3D registration, the facet joint 3D translation and segmental vertebral 3D rotation were analyzed at the operated level (L5-S1) and adjacent level (L4-L5).

Using PET/CT Bone Scan Dynamic Data to Evaluate Tibia Remodeling When a Taylor Spatial Frame Is Used: Short and Longer Term Differences.

Eighteen consecutive patients, treated with a Taylor Spatial Frame for complex tibia conditions, gave their informed consent to undergo Na(18)F(-) PET/CT bone scans. We present a Patlak-like analysis utilizing an approximated blood time-activity curve eliminating the need for blood aliquots. Additionally, standardized uptake values (SUV) derived from dynamic acquisitions were compared to this Patlak-like approach.

Evaluation of mobility and stability in the Discover artificial disc: an in vivo motion study using high-accuracy 3D CT data.

Object: Artificial disc replacement (ADR) devices are unlike implants used in cervical fusion in that they are continuously exposed to stress not only within the implant site but also at their site of attachment to the adjacent vertebra. An imaging technique with higher accuracy than plain radiography and with the possibility of 3D visualization would provide more detailed information about the motion quality and stability of the implant in relation to the vertebrae. Such high-accuracy studies have previously been conducted with radiostereometric analysis (RSA), which requires implantation of tantalum markers in the adjacent vertebrae.

Can Na18F PET/CT be used to study bone remodeling in the tibia when patients are being treated with a Taylor Spatial Frame?

Monitoring and quantifying bone remodeling are of interest, for example, in correction osteotomies, delayed fracture healing pseudarthrosis, bone lengthening, and other instances. Seven patients who had operations to attach an Ilizarov-derived Taylor Spatial Frame to the tibia gave informed consent. Each patient was examined by Na(18)F PET/CT twice, at approximately six weeks and three months after the operation.

In vivo and ex vivo measurement of polyethylene wear in total hip arthroplasty: comparison of measurements using a CT algorithm, a coordinate-measuring machine, and a micrometer.

Background: Determination of the amount of wear in a polyethylene liner following total hip arthroplasty (THA) is important for both the clinical care of individual patients and the development of new types of liners.

Patients And Methods: We measured in vivo wear of the polyethylene liner using computed tomography (CT) (obtained in the course of regular clinical care) and compared it to coordinate-measuring machine (CMM) readings. Also, changes in liner thickness of the same retrieved polyethylene liner were measured using a micrometer, and were compared to CT and CMM measurements.

A new automated way to measure polyethylene wear in THA using a high resolution CT scanner: method and analysis.

As the most advantageous total hip arthroplasty (THA) operation is the first, timely replacement of only the liner is socially and economically important because the utilization of THA is increasing as younger and more active patients are receiving implants and they are living longer. Automatic algorithms were developed to infer liner wear by estimating the separation between the acetabular cup and femoral component head given a computed tomography (CT) volume. Two series of CT volumes of a hip phantom were acquired with the femoral component head placed at 14 different positions relative to the acetabular cup.

Technical requirements for Na¹⁸F PET bone imaging of patients being treated using a Taylor spatial frame.

Unlabelled: Diagnosis of new bone growth in patients with compound tibia fractures or deformities treated using a Taylor spatial frame is difficult with conventional radiography because the frame obstructs the images and creates artifacts. The use of Na(18)F PET studies may help to eliminate this difficulty.

Methods: Patients were positioned on the pallet of a clinical PET/CT scanner and made as comfortable as possible with their legs immobilized.

Clinical application of in vivo treatment delivery verification based on PET/CT imaging of positron activity induced at high energy photon therapy.

The purpose of this study was to investigate in vivo verification of radiation treatment with high energy photon beams using PET/CT to image the induced positron activity. The measurements of the positron activation induced in a preoperative rectal cancer patient and a prostate cancer patient following 50 MV photon treatments are presented. A total dose of 5 and 8 Gy, respectively, were delivered to the tumors.

Dynamic PET/CT measurements of induced positron activity in a prostate cancer patient after 50-MV photon radiation therapy.

Background: The purpose of this work was to reveal the research interest value of positron emission tomography (PET) imaging in visualizing the induced tissue activity post high-energy photon radiation treatment. More specifically, the focus was on the possibility of retrieving data such as tissue composition and physical half-lives from dynamic PET acquisitions, as positron-emitting radionuclides such as 15O, 11C, and 13N are produced in vivo during radiation treatment with high-energy photons (>15 MeV). The type, amount, and distribution of induced positron-emitting radionuclides depend on the irradiated tissue cross section, the photon spectrum, and the possible perfusion-driven washout.

A new technique for measuring wear in total hip arthroplasty using computed tomography.

Accurately estimating polyethylene wear in 3 dimensions, without the need for additional procedures or equipment, is of significant interest. We investigated the use of a high-resolution clinical computed tomographic (CT) scanner to estimate femoral head displacement relative to the cup as an indirect method of estimating polyethylene wear. A hip phantom was used to simulate the 3-dimensional displacement of a femoral head.

Motion analysis of total cervical disc replacements using computed tomography: preliminary experience with nine patients and a model.

Background: Cervical total disc replacement (CTDR) is an alternative to anterior fusion. Therefore, it is desirable to have an accurate in vivo measurement of prosthetic kinematics and assessment of implant stability relative to the adjacent vertebrae.

Purpose: To devise an in vivo CT-based method to analyze the kinematics of cervical total disc replacements (CTDR), specifically of two prosthetic components between two CT scans obtained under different conditions.

Quantifying the Increase in Radiation Exposure Associated with SPECT/CT Compared to SPECT Alone for Routine Nuclear Medicine Examinations.

Purpose. We quantify the additional radiation exposure in terms of effective dose incurred by patients in the CT portion of SPECT/CT examinations. Methods.

Validation of a 3D CT method for measurement of linear wear of acetabular cups.

Background: We evaluated the accuracy and repeatability of a 3D method for polyethylene acetabular cup wear measurements using computed tomography (CT). We propose that the method be used for clinical in vivo assessment of wear in acetabular cups.

Material And Methods: Ultra-high molecular weight polyethylene cups with a titanium mesh molded on the outside were subjected to wear using a hip simulator.

Role of fusion of prone FDG-PET and magnetic resonance imaging of the breasts in the evaluation of breast cancer.

The purpose of this study is to report further about the statistically significant results from a prospective study, which suggests that fusion of prone F-18 Fluoro-deoxy-glucose (FDG) positron emission tomography (PET) and magnetic resonance (MR) breast scans increases the positive predictive value (PPV) and specificity for patients in whom the MR outcome alone would be nonspecific. Thirty-six women (mean age, 43 years; range, 24-65 years) with 90 lesions detected on MR consented to undergo a FDG-PET scan. Two blinded readers evaluated the MR and the computer tomography (CT) attenuation-corrected prone FDG-PET scans side-by-side, then after the volumes were superimposed (fused).

A new technique for diagnosis of acetabular cup loosening using computed tomography: preliminary experience in 10 patients.

Background And Purpose: Considerable migration of the acetabular cup is required for diagnosis of loosening by conventional radiography. We have developed a new clinically applicable method for assessment of cup loosening using computed tomography (CT).

Patients And Methods: 10 patients scheduled for revision hip replacement due to suspected wear or loosening were scanned twice with CT under torsion loading of the prosthesis.