Biomedical subjects

James H Anderson

Publications and source records attributed to James H Anderson.

8 recordsLinked to original sources

PubMed2006

Integrative haptic and visual interaction for simulation of PMMA injection during vertebroplasty.

In vertebroplasty, physician relies on both sight and feel to properly place the bone needle through various tissue types and densities, and to help monitor the injection of PMMA or cement into the vertebra. Incorrect injecting and reflux of the PMMA into areas where it should not go can result in detrimental clinical complication. This paper focuses on the human-computer interaction for simulating PMMA injection in our virtual spine workstation. Fluoroscopic images are generated from the CT patient volume data and simulated volumetric flow using a time varying 4D volume rendering algorithm. The user's finger movement is captured by a data glove. Immersion CyberGrasp is used to provide the variable resistance felt during injection by constraining the user's thumb. Based on our preliminary experiments with our interfacing system comprising simulated fluoroscopic imaging and haptic interaction, we found that the former has a larger impact on the user's control during injection.

Computer Simulation↗

PubMed2006

Flow visualization for interactive simulation of drugs injection during chemoembolization.

Chemoembolization is an important therapeutic procedure. A catheter was navigated to the artery that feeds the tumor, and chemotherapy drugs and embolus are injected directly into the tumor. There is a risk that embolus may lodge incorrectly and deprive normal tissue of its blood supply. This paper focuses on visualization of the flow particles in simulation of chemotherapy drugs injection for training of hand-eye coordination skills. We assume that the flow follows a defined path in the hepatic vascular system from the catheter tip. The vascular model is constructed using sweeping and blending operations. Quadrilaterals which are aligned to face the viewer are drawn for the trail of each particle. The quadrilateral in the trail is determined using bilinear interpolation. On simulated fluoroscopic image, the flow is rendered as overlaying and semitransparent quadrilaterals representing the particles' trails. This visualization model achieves a good visual approximation of the flow of particles inside the vessels under fluoroscopic imaging.

Antineoplastic Agents↗

PubMed2004

Measurement of insulin absorption and insulin action.

For the practical implementation of every type of insulin therapy it is necessary to know both the time course of action of therapeutically used short- and long-acting insulin preparations and the factors influencing such time-action profiles. The only reliable way to obtain the required quantitative information about the pharmacokinetic and glucodynamic properties of insulin preparations has been the use of the euglycemic glucose clamp technique. The first studies with each new insulin formulation or insulin application technique should be performed with healthy subjects in order to have the most comparable study conditions. Thereafter, results from such clinical-experimental studies should be verified in similar studies with patients with diabetes. Earlier investigational approaches, which either had been limited to the determination of the pharmacokinetic properties of insulin preparations or had used the quantitative decrease of the blood glucose level as a measure of the pharmacodynamic properties, do not provide valid quantitative results. The proposed glucose clamp technique makes possible the quantitative study of the pharmacokinetic and pharmacodynamic properties of insulin preparations under comparative and reproducible conditions.

Blood Glucose↗

PubMed2003

Dynamic exercise imaging with an MR-compatible stationary cycle within the general electric open magnet.

Many cases of muscular ischemia do not manifest without increased metabolic demand. Hence, diagnosis of intermittent claudication often requires inducing physiologic challenge, such as by exercise. Cine phase-contrast MRI can concurrently acquire cross-sectional vascular anatomy and through-plane blood velocities, enabling blood flow rate quantification. An MR-compatible stationary cycle was designed, constructed, and tested for flow quantification in large arteries during lower-limb exercise in a General Electric Signa SP 0.5 T open magnet. The cycle demonstrated smooth cycling during image acquisition, has freewheeling capability, is adjustable for subject size and strength, and can quantify workload. A healthy 59-year-old male was imaged at the supraceliac and infrarenal levels of the abdominal aorta at rest and during exercise. An exercise workload of 47.9 W was achieved. His heart rate increased from 52 to 78 bpm, supraceliac flow increased from 1.7 to 3.7 L/min, and infrarenal flow increased from 0.4 to 3.2 L/min from rest to exercise.

Aorta, Abdominal↗

PubMed2003

Effect of long-term exposure to insulin lispro on the induction of antibody response in patients with type 1 or type 2 diabetes.

OBJECTIVE: To determine the long-term effects of insulin lispro on inducing lispro-specific, insulin-specific, and cross-reactive (reactive with both insulin lispro and human insulin) antibodies. RESEARCH DESIGN AND METHODS: A multinational, multicenter combination of controlled and noncontrolled, open-label studies of 4.5 years' duration was designed to evaluate the long-term immunologic profile of subcutaneously administered insulin lispro. A total of 1,221 patients (men and women; 12-81 years of age) with type 1 or type 2 diabetes were enrolled. Circulating anti-insulin antibodies were measured using radioimmunoassays. RESULTS: Insulin-specific and lispro-specific antibody responses were within the background noise levels of the assays. Significant elevations of antibody were confined to a cross-reactive antibody response. Antibody levels resulting from prior exposure to long- and short-acting insulins changed little after transfer to insulin lispro and remained within or near the baseline levels. De novo exposure to insulin lispro resulted in increases in cross-reactive but not insulin- or lispro-specific antibody levels. Cross-reactive insulin antibodies developed more readily in patients with type 1 diabetes than in those with type 2 diabetes. Long-term antibody responses tended to decrease over time and returned to baseline or near-baseline levels by the end of the long-term studies. No evidence of an anamnestic antibody response could be found in individuals treated intermittently with insulin lispro. CONCLUSIONS: The immunogenic profile of patients treated with insulin lispro was comparable to that of patients treated with recombinant human insulin. Inductions of significant levels of specific or cross-reactive antibodies were not observed in patients who had received insulin previously. No significant antibody-dependent increases in insulin dosage requirements were noted in these patients. The incidence of insulin allergy was not different from that in patients treated with recombinant regular human insulin.

Adolescent↗

PubMed2002

System for robotically assisted prostate biopsy and therapy with intraoperative CT guidance.

RATIONALE AND OBJECTIVES: The purpose of this study was to assess the work-in-progress prototype of an image-guided, robotic system for accurate and consistent placement of transperineal needles into the prostate with intraoperative image guidance inside the gantry of a computed tomographic (CT) scanner. MATERIALS AND METHODS: The coach-mounted system consists of a seven-degrees-of-freedom, passive mounting arm: a remote-center-of-motion robot; and a motorized, radiolucent needle-insertion device to deliver 17-18-gauge implant and biopsy needles into the prostate with the transperineal route. The robot is registered to the image space with a stereotactic adapter. The surgeon plans and controls the intervention in the CT scanner room with a desktop computer that receives DICOM images from the CT scanner. The complete system fits in a carry-on suitcase, does not need calibration, and does not utilize vendor-specific features of the CT scanner. RESULTS: In open air, the average accuracy was better than 1 mm at a 5-8-cm depth. In various phantoms, the average orientation error was 1.3 degrees, and the average distance between the needle tip and the target was 2 mm. CONCLUSION: Results of preliminary experiments indicate that this robotic system may be suitable for transperineal needle placement into the prostate and shows potential in a variety of other percutaneous clinical applications.

Biopsy, Needle↗

PubMed2002

Training and pretreatment planning of interventional neuroradiology procedures--initial clinical validation.

A PC based system for simulating image-guided interventional neuroradiological procedures for physician training and patient specific pretreatment planning is described. The system allows physicians to manipulate and interface interventional devices such as catheters, guidewires, stents and coils within 2-D and hybrid surface and volume rendered 3-D patient vascular images in real time. A finite element method is employed to model the interaction of the catheters and guidewires with the vascular system. Fluoroscopic, roadmapping and volume rendered 3-D presentations of the vasculature are provided. System software libraries allow for the use of commonly employed catheters, guidewires, stents and occluding coils of various shapes and sizes. The results of an initial clinical validation suggest that the experience gained from our simulator is comparable with that of using a vascular phantom. We are conducting further validation with the aim of providing patient specific pretreatment planning.

Angioplasty, Balloon↗

PubMedDate not supplied

The 1st balloon valvuloplasty: an historical note.

Balloon valvuloplasty (BV) is currently the treatment of choice for pulmonic stenosis in humans and dogs. Before permission was obtained to attempt the 1st BV in a child in 1982, the safety and efficacy of the procedure were tested in 1980 in an English Bulldog with spontaneous pulmonic stenosis. A fatal outcome would have caused indefinite postponement of BV in human patients, a procedure that currently benefits over 25,000 patients a year worldwide. This article describes the initial test procedure and its fortunate outcome in spite of unrecognized coronary anomalies in the bulldog. A small balloon was used in the test procedure, and fatal disruption of the anomalous left coronary artery (CA) did not occur as it has in several bulldogs since that time.

Animals↗