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Articles 301 - 330 of 417

Full-Text Articles in Biomedical Engineering and Bioengineering

In Vivo Quantitation Of Rare Circulating Tumor Cells By Multiphoton Intravital Flow Cytometry, Wei He, Haifeng Wang, Lynn C. Hartmann, Ji-Xin Cheng, Phillip S. Low Jul 2007

In Vivo Quantitation Of Rare Circulating Tumor Cells By Multiphoton Intravital Flow Cytometry, Wei He, Haifeng Wang, Lynn C. Hartmann, Ji-Xin Cheng, Phillip S. Low

Other Nanotechnology Publications

Quantitation of circulating tumor cells (CTCs) constitutes an emerging tool for the diagnosis and staging of cancer, assessment of response to therapy, and evaluation of residual disease after surgery. Unfortunately, no existing technology has the sensitivity to measure the low numbers of tumor cells (< 1 CTC per ml of whole blood) that characterize minimal levels of disease. We present a method, intravital flow cytometry, that noninvasively counts rare CTCs in vivo as they flow through the peripheral vasculature. The method involves i.v. injection of a tumor-specific fluorescent ligand followed by multiphoton fluorescence imaging of superficial blood vessels to quantitate the flowing CTCs. Studies in mice with metastatic tumors demonstrate that CTCs can be quantitated weeks before metastatic disease is detected by other means. Analysis of whole blood samples from cancer patients further establishes that human CTCs can be selectively labeled and quantitated when present at approximate to 2 CTCs per ml, opening opportunities for earlier assessment of metastatic disease.

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Statistical Analysis Of Joint Short-Term And Long-Term Survival In Resuscitation Research, Charles F. Babbs Apr 2007

Statistical Analysis Of Joint Short-Term And Long-Term Survival In Resuscitation Research, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Objective: To develop statistical tools that utilize combined initial survival data and post-resuscitation survival data to test the null hypothesis that true, population-wide outcomes following experimental CPR interventions are not different from control. Method: A new test statistic, d2, for evaluating Type 1 error is derived from a bivariate, two-dimensional analysis of categorical initial resuscitation and post-resuscitation survival data, which are statistically independent because they are obtained during non-overlapping periods of time. The d2 test statistic, which is distributed as a chi-squared distribution, is derived from first principles and validated using Monte Carlo methods of computer simulation for thousands of …

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Hyperthermic Effects Of Gold Nanorods On Tumor Cells, Terry B. Huff, Ling Tong, Matthew N. Hansen, Ji-Xin Cheng, Alexander Wei Feb 2007

Hyperthermic Effects Of Gold Nanorods On Tumor Cells, Terry B. Huff, Ling Tong, Matthew N. Hansen, Ji-Xin Cheng, Alexander Wei

Other Nanotechnology Publications

Plasmon-resonant gold nanorods, which have large absorption cross sections at near-infrared frequencies, are excellent candidates as multifunctional agents for image-guided therapies based on localized hyperthermia. The controlled modification of the surface chemistry of the nanorods is of critical importance, as issues of cell-specific targeting and nonspecific uptake must be addressed prior to clinical evaluation. Nanorods coated with cetyltrimethylammonium bromide (a cationic surfactant used in nanorod synthesis) are internalized within hours into KB cells by a nonspecific uptake pathway, whereas the careful removal of cetyltrimethylammonium bromide from nanorods functionalized with folate results in their accumulation on the cell surface over the …

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A Novel Open Field Activity Detector To Determine Spatial And Temporal Movement Of Laboratory Animals After Injury And Disease, Andrew O. Koob, John Cirillo, Charles F. Babbs Oct 2006

A Novel Open Field Activity Detector To Determine Spatial And Temporal Movement Of Laboratory Animals After Injury And Disease, Andrew O. Koob, John Cirillo, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Among the wide range of tests for laboratory animal behavior after neurological injury or disease, each has its benefits and drawbacks. The varied behavior that an animal exhibits makes it difficult to decide which test to use. However, a fundamental instinct for the laboratory animal is to explore when placed in a new environment. A way to test exploratory behavior is in the open field. Here, we introduce a simple activity box without the use of video equipment to determine the exploratory movement of a rat after traumatic brain injury. The activity box is an open field, and the rat …

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Design Of Near-Optimal Waveforms For Chest And Abdominal Compression And Decompression In Cpr Using Computer-Simulated Evolution, Charles F. Babbs Jan 2006

Design Of Near-Optimal Waveforms For Chest And Abdominal Compression And Decompression In Cpr Using Computer-Simulated Evolution, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Objective: To discover design principles underlying the optimal waveforms for external chest and abdominal compression and decompression during cardiac arrest and CPR. Method: A 14-compartment mathematical model of the human cardiopulmonary system is used to test successive generations of randomly mutated external compression waveforms during cardiac arrest and resuscitation. Mutated waveforms that produced superior mean perfusion pressure became parents for the next generation. Selection was based upon either systemic perfusion pressure (SPP=thoracic aortic minus right atrial pressure) or upon coronary perfusion pressure (CPP=thoracic aortic pressure minus myocardial wall pressure). After simulations of 64,414 individual CPR episodes, 40 highly evolved waveforms …

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A New Biomechanical Head Injury Criterion, Charles F. Babbs Jan 2006

A New Biomechanical Head Injury Criterion, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

This paper presents a new analysis of the physics of closed head injury caused by intense acceleration of the head. At rest a 1 cm gap filled with cerebrospinal fluid (CSF) separates the human brain from the skull. During impact whole head acceleration induces artificial gravity within the skull. Because its density differs slightly from that of CSF, the brain accelerates, strikes the inner aspect of the rigid skull, and undergoes viscoelastic deformation. Analytical methods for a lumped parameter model of the brain predict internal brain motions that correlate well with published high-speed photographic studies. The same methods predict a …

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In Vitro And In Vivo Two-Photon Luminescence Imaging Of Single Gold Nanorods, Haifeng Weng, Terry B. Huff, Daniel A. Zweifel, Wei He, Philip S. Low, Alexander Wei, Ji-Xin Cheng Nov 2005

In Vitro And In Vivo Two-Photon Luminescence Imaging Of Single Gold Nanorods, Haifeng Weng, Terry B. Huff, Daniel A. Zweifel, Wei He, Philip S. Low, Alexander Wei, Ji-Xin Cheng

Other Nanotechnology Publications

Gold nanorods excited at 830 nm on a far-field laser-scanning microscope produced strong two-photon luminescence (TPL) intensities, with a cos(4) dependence on the incident polarization. The TPL excitation spectrum can be superimposed onto the longitudinal plasmon band, indicating a plasmon-enhanced two-photon absorption cross section. The TPL signal from a single nanorod is 58 times that of the two-photon fluorescence signal from a single rhodamine molecule. The application of gold nanorods as TPL imaging agents is demonstrated by in vivo imaging of single nanorods flowing in mouse ear blood vessels.

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Intravenous Polyethylene Glycol Inhibits The Loss Of Cerebral Cells After Brain Injury, Andrew O. Koob, Bradley S. Duerstock, Charles F. Babbs, Yinlong Sun, Richard B. Borgens Oct 2005

Intravenous Polyethylene Glycol Inhibits The Loss Of Cerebral Cells After Brain Injury, Andrew O. Koob, Bradley S. Duerstock, Charles F. Babbs, Yinlong Sun, Richard B. Borgens

Weldon School of Biomedical Engineering Faculty Publications

We have tested the effectiveness of polyethylene glycol (PEG) to restore the integrity of neuronal membranes after mechanical damage secondary to severe traumatic brain injury (TBI) produced by a standardized head injury model in rats. We provide additional detail on the standardization of this model, particularly the use and storage of foam bedding that serves to both support the animal during the impact procedure and to dampen the acceleration of the brass weight. Further, we employed a dye exclusion technique using ethidium bromide (EB; quantitative evaluation) and horseradish peroxidase (HRP; qualitative evaluation). Both have been successfully used previously to evaluate …

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A Dose-Response Curve For The Negative Bias Pressure Of An Intrathoracic Pressure Regulator During Cpr, Charles F. Babbs, Demetris Yannopoulos Oct 2005

A Dose-Response Curve For The Negative Bias Pressure Of An Intrathoracic Pressure Regulator During Cpr, Charles F. Babbs, Demetris Yannopoulos

Weldon School of Biomedical Engineering Faculty Publications

An intrathoracic pressure regulator (ITPR) is a device that can be added to the external end of an endotracheal tube to create controlled negative airway pressure between positive pressure ventilations. The resulting downward bias of the airway pressure baseline promotes increased venous return and enhanced circulation during CPR and also during hypovolemic shock. In the present study we exercised a mathematical model of the human cardiopulmonary system, including airways, lungs, a 4 chambered heart, great vessels, peripheral vascular beds, and the biomechanics of chest compression and recoil, to determine the relationship between systemic perfusion pressure during CPR and the value …

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Optimal Control Theory Applied To A Difference Equation Model Of Cardiopulmonary Resuscitation, Eunok Jung, Charles F. Babbs, Suzanne Lenhart, Vladimir A. Protopoescu Oct 2005

Optimal Control Theory Applied To A Difference Equation Model Of Cardiopulmonary Resuscitation, Eunok Jung, Charles F. Babbs, Suzanne Lenhart, Vladimir A. Protopoescu

Weldon School of Biomedical Engineering Faculty Publications

Objective: To apply the mathematical techniques of optimal control theory (OCT) to a validated model of the human circulation during cardiopulmonary resuscitation (CPR), so as to discover improved waveforms for chest compression and decompression that maximize the systemic perfusion pressure (SPP). Methods: The human circulatory system is represented by seven difference equations, which describe the pressure changes in systemic vascular compartments caused by chest compression. The forcing term is the intrathoracic pressure generated by the external chest compression, which is taken as the “control” variable for the system. The optimum waveform of this forcing pressure as a function of time, …

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Biophysics Of Cardiopulmonary Resuscitation With Periodic Z-Axis Acceleration Of Abdominal Compression At Aortic Resonant Frequencies, Charles F. Babbs Sep 2005

Biophysics Of Cardiopulmonary Resuscitation With Periodic Z-Axis Acceleration Of Abdominal Compression At Aortic Resonant Frequencies, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Periodic z-axis acceleration (pGz)-CPR involves oscillating motion of a whole patient in the head-to-foot dimension on a mechanized table. The method is able to sustain blood flow and long-term survival during and after prolonged cardiac arrest in anesthetized pigs. However, the exact mechanism by which circulation of blood is created has remained unknown. Objectives: To explain the hemodynamic mechanism of pGz-CPR and to suggest theoretically useful improvements. Method: Computer modeling using a hybrid analytical-numerical approach, based upon Newton’s second law of motion for fluid columns in the aorta and vena cavae, Ohm’s law for resistive flow through vascular beds, and …

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Effects Of An Impedance Threshold Valve Upon Hemodynamics In Standard Cpr: Studies In A Refined Computational Model, Charles F. Babbs Mar 2005

Effects Of An Impedance Threshold Valve Upon Hemodynamics In Standard Cpr: Studies In A Refined Computational Model, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

An impedance threshold valve (ITV) is a new airway adjunct for resuscitation that permits generation of a small vacuum in the chest during the recoil phase of chest compression. Objectives: To explore in detail the expected magnitude and the hemodynamic mechanisms of circulatory augmentation by an ITV in standard CPR. Method: A 14-compartment mathematical model of the human cardiopulmonary system—upgraded to include applied chest compression force, elastic recoil of the chest wall, anatomic details of the heart and lungs, and the biomechanics of mediastinal compression—is exercised to explore the conditions required for circulatory augmentation by an ITV during various modes …

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Relative Effectiveness Of Interposed Abdominal Compression Cpr: Sensitivity Analysis And Recommended Compression Rates, Charles F. Babbs Jan 2005

Relative Effectiveness Of Interposed Abdominal Compression Cpr: Sensitivity Analysis And Recommended Compression Rates, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Interposed abdominal compression (IAC)-CPR incorporates alternating chest and abdominal compressions to generate enhanced artificial circulation during cardiac arrest. The technique has been generally successful in improving blood flow and survival compared to standard CPR; however some questions remain. Objective: To determine "why does IAC-CPR produce more apparent benefit in some subjects than in others? and "what is the proper compression rate, given that there are actually two compressions (chest and abdomen) in each cycle?" Method: Computer models provide a means to search for subtle effects in complex systems. The present study employs a validated 12-compartment mathematical model of the human …

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Brain Motion And Deformation During Closed Head Injury In The Presence Of Cerebrospinal Fluid, Charles F. Babbs Jun 2004

Brain Motion And Deformation During Closed Head Injury In The Presence Of Cerebrospinal Fluid, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

This paper presents a new analysis of the physics of closed head injury following brief, intense acceleration of the head. It focuses upon the buoyancy of the brain in cerebrospinal fluid, which protects against damage, the propagation of strain waves through the brain substance, which causes damage, and the concentration of strain in critical anatomic regions, which magnifies damage. Numerical methods are used to create animations or "movies" of brain motion and deformation. Initially a 1 cm gap filled with cerebrospinal fluid (CSF) separates the brain from the skull. Whole head acceleration induces artificial gravity within the skull. The brain …

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Meta-Analysis Of Two-Treatment Clinical Trials Including Both Continuous And Dichotomous Results, Charles F. Babbs Jan 2004

Meta-Analysis Of Two-Treatment Clinical Trials Including Both Continuous And Dichotomous Results, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

To expedite the timely creation of medical practice guidelines, a meta-analytic method was developed to combine of both dichotomous survival data and continuous physiologic data from multiple studies comparing the same innovative clinical intervention to standard care. The method is adapted for synthesis of small, early studies of novel treatments. An aggregate ratio, R*, of the observed treatment effect to a clinically optimal treatment effect for studies in a series is computed, and compared to the 95% confidence limit for R* under the null hypothesis. Weights assigned to each study may reflect its precision, quality, or clinical relevance. Input data …

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Optimizing Chest Compression To Rescue Ventilation Ratios During One-Rescuer Cpr By Professionals And Lay Persons: Children Are Not Just Little Adults, Charles F. Babbs, Vinay Nadkarni Jan 2004

Optimizing Chest Compression To Rescue Ventilation Ratios During One-Rescuer Cpr By Professionals And Lay Persons: Children Are Not Just Little Adults, Charles F. Babbs, Vinay Nadkarni

Weldon School of Biomedical Engineering Faculty Publications

Objective: To estimate the optimum ratio of chest compressions to ventilations for onerescuer CPR that maximizes systemic oxygen delivery in children. Method: Equations describing oxygen delivery and blood flow during CPR as functions of the number of compressions and the number of ventilations delivered over time were adapted from the former work of Babbs and Kern. These equations were solved explicitly as a function of body weight, using scaling algorithms based upon principles of developmental anatomy and physiology. Results: The optimal compression to ventilation (C/V) ratios for infants and younger children increase sharply as a function of body weight. Optimal …

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Simplified Meta-Analysis Of Clinical Trials In Resuscitation, Charles F. Babbs Jan 2003

Simplified Meta-Analysis Of Clinical Trials In Resuscitation, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Objective: To present and demonstrate a new simplified method for synthesizing results of multiple clinical trials in resuscitation research. Methods: The mean difference across studies in the proportion of favorable outcomes between experimental and control groups is calculated. This difference is shown to have a t-distribution. Its significance can be ascertained with a simple t-test. The analysis can be implemented in a one-page computer spreadsheet. Results: Simplified meta-analysis provides high sensitivity and can be extended to include weighting of studies according to size or quality, comparison of subgroups of studies, tests for outliers, and calculation of the power of the …

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Interposed Abdominal Compression Cpr: A Comprehensive Evidence Based Review, Charles F. Babbs Jan 2003

Interposed Abdominal Compression Cpr: A Comprehensive Evidence Based Review, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Interposed abdominal compression (IAC)-CPR includes all steps of standard external CPR with the addition of manual mid-abdominal compressions in counterpoint to the rhythm of chest compressions. IAC-CPR can increase blood flow during CPR about two fold compared to standard CPR without IAC, as shown by 6 of 6 studies in computer models and 19 of 20 studies in various animal models. The addition of IAC has clinical benefit in humans, as indicated in 10 of 12 small to medium sized clinical studies. The technique increases the frequency of immediate return of spontaneous circulation for in-hospital resuscitations from roughly 25% to …

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Circulatory Adjuncts: Newer Methods Of Cardiopulmonary Resuscitation, Charles F. Babbs Jan 2002

Circulatory Adjuncts: Newer Methods Of Cardiopulmonary Resuscitation, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Current standard CPR only provides about one fifth of normal forward blood flow and only about one quarter of the blood flow that is theoretically possible with advanced external techniques. Two such techniques are now approved as optional alternatives in resuscitation guidelines. This chapter reviews modern understanding of the physiology of blood flow during CPR and practical aspects of utilizing more advanced resuscitation methods. When properly performed these methods produce statistically significant increases in survival.

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Optimum Compression To Ventilation Ratios In Cpr Under Realistic, Practical Conditions: A Physiological And Mathematical Analysis, Charles F. Babbs, Karl B. Kern Jan 2002

Optimum Compression To Ventilation Ratios In Cpr Under Realistic, Practical Conditions: A Physiological And Mathematical Analysis, Charles F. Babbs, Karl B. Kern

Weldon School of Biomedical Engineering Faculty Publications

Objective: To develop and evaluate a practical formula for the optimum ratio of compressions to ventilations in CPR. The optimum value of a parameter is that for which a desired result is maximized. Here the desired result is assumed to be either oxygen delivery to peripheral tissues or a combination of oxygen delivery and waste product removal. Method: Equations describing oxygen delivery and blood flow during CPR as functions of the number of compressions and the number of ventilations delivered over time were developed from principles of classical physiology. These equations were solved explicitly in terms of the compression/ventilation ratio …

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Consensus Evidence Evaluation In Resuscitation Research: Analysis Of Type I And Type Ii Errors, Charles F. Babbs Jan 2001

Consensus Evidence Evaluation In Resuscitation Research: Analysis Of Type I And Type Ii Errors, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Objective: This paper addresses the following statistical question: ‘if genuine improvements in cardiopulmonary resuscitation (CPR) were discovered that doubled the probability of resuscitation success in a series of randomized clinical trials, would they be recognized and incorporated into consensus guidelines?’ Methods: Statistical powers for hypothetical individual clinical trials comparing experimental and control CPR were computed as a function of the study N when the true probabilities for immediate survival, 24 h survival, and discharge survival in the experimental group were twice those in the control group. Next, the binomial distributions describing the numbers of statistically significant studies in a series …

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Biomechanics Of Heading A Soccer Ball: Implications For Player Safety, Charles F. Babbs Jan 2001

Biomechanics Of Heading A Soccer Ball: Implications For Player Safety, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

To better understand the risk and safety of heading a soccer ball, the author created a set of simple mathematical models based upon Newton’s second law of motion to describe the physics of heading. These models describe the player, the ball, the flight of the ball before impact, the motion of the head and ball during impact, and the effects of all of these upon the intensity and the duration of acceleration of the head. The calculated head accelerations were compared to those during presumably safe daily activities of jumping, dancing, and head nodding and also were related to established …

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Efficacy Of Interposed Abdominal Compression-Cardiopulmonary Resuscitation (Cpr), Active Compression And Decompression-Cpr, And Lifestick Cpr: Basic Physiology In A Spreadsheet Model, Charles F. Babbs Jan 2000

Efficacy Of Interposed Abdominal Compression-Cardiopulmonary Resuscitation (Cpr), Active Compression And Decompression-Cpr, And Lifestick Cpr: Basic Physiology In A Spreadsheet Model, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

This study was undertaken to understand and predict results of experimental cardiopulmonary resuscitation (CPR) techniques involving compression and decompression of either the chest or the abdomen. Simple mathematical models of the adult human circulation were used. Assumptions of the models are limited to normal human anatomy and physiology, the definition of compliance (volume change/pressure change), and Ohm’s law (flow = pressure / resistance). Interposed abdominal compression-CPR, active compression and decompression of the chest, and Lifestick CPR, which combines interposed abdominal compression and active compression and decompression, produce, respectively, 1.9-, 1.2-, and 2.4- fold greater blood flow than standard CPR and …

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Mechanics Of Cpr Performed With The Patient On A Soft Bed Versus A Hard Surface, John M. Boe, Charles F. Babbs Jan 1999

Mechanics Of Cpr Performed With The Patient On A Soft Bed Versus A Hard Surface, John M. Boe, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Objective: To study the effects of underlying bed softness versus stiffness on the effectiveness of chest compressions in CPR. Methods: For a wide range of bed stiffness constants, mathematical models describing compression of the human chest supported by a hospital bed were created for an adult thorax experiencing either a sinusoidal compressive force or a sinusoidal sternal displacement. Results: With 5 cm peak displacement, sternum-to-spine compression fell from 4.3 to 1.0 cm, and peak power fell from 59 to 23 Watts, as bed stiffness decreased from 50,000 to 5,000 N/m. Less than 35% of maximal chest compression occurred at a …

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Multiresolution Detection Of Spiculated Lesions In Digital Mammograms, Sheng Liu, Charles F. Babbs, Edward Delp Jan 1998

Multiresolution Detection Of Spiculated Lesions In Digital Mammograms, Sheng Liu, Charles F. Babbs, Edward Delp

Weldon School of Biomedical Engineering Faculty Publications

In this paper we present a novel multiresolution scheme for the detection of spiculated lesions in digital mammograms. First, a multiresolution representation of the original mammogram is obtained using a linear phase nonseparable 2-D wavelet transform. A set of features is then extracted at each resolution in the wavelet pyramid for every pixel. This approach addresses the difficulty of predetermining the neighborhood size for feature extraction to characterize objects that may appear in different sizes. Detection is performed from the coarsest resolution to the finest resolution using a binary tree classifier. This top-down approach requires less computation by starting with …

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Theoretically Optimal Duty Cycles For Chest And Abdominal Compression During External Cardiopulmonary Resuscitation, Charles F. Babbs, Keir Thelander Jan 1995

Theoretically Optimal Duty Cycles For Chest And Abdominal Compression During External Cardiopulmonary Resuscitation, Charles F. Babbs, Keir Thelander

Weldon School of Biomedical Engineering Faculty Publications

Objective: To use an electronic model of human circulation to compare the hemodynamic effects of different durations of chest compression during external CPR, both with, and without interposed abdominal compression (IAC). Methods: An electrical analog model of human circulation was studied on digital computer workstations using SPICE, a general-purpose circuit simulation program. In the model the heart and blood vessels were represented as resistive-capacitive networks, pressures as voltages, blood flow as electric current, blood inertia as inductance, and cardiac and venous valves as diodes. External pressurization of the heart and great vessels, as would occur in IAC-CPR, was simulated by …

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Preliminary Results Of Deferoxamine And L1 Treatment Of Spinal Cord Ischemia, David G. Reuter, Willis A. Tacker Jr, Charles F. Babbs, Stephen F. Badylak, William D. Voorhees, Peter E. Konrad Jan 1995

Preliminary Results Of Deferoxamine And L1 Treatment Of Spinal Cord Ischemia, David G. Reuter, Willis A. Tacker Jr, Charles F. Babbs, Stephen F. Badylak, William D. Voorhees, Peter E. Konrad

Weldon School of Biomedical Engineering Faculty Publications

No abstract provided.

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Clinical Roc Studies Of Digital Stereo Mammography, Tarek Z. Elabbady, Charles F. Babbs, Valerie P. Jackson, Edward J. Delp, David M. Chelberg, Zygmunt Pizlo, Leslie A. Geddes Jan 1995

Clinical Roc Studies Of Digital Stereo Mammography, Tarek Z. Elabbady, Charles F. Babbs, Valerie P. Jackson, Edward J. Delp, David M. Chelberg, Zygmunt Pizlo, Leslie A. Geddes

Weldon School of Biomedical Engineering Faculty Working Papers

The objective of this study was to explore and document the diagnostic utility of digital stereo mammography for the detection of localized breast cancer in women. In it we character­ized the ability of experienced mammographers, general radiologists, and non-radiologists to detect three types of tumor masses embedded within a heterogeneous background of normal tis­sue elements in numerically simulated digital mammograms. The simulated mammograms were displayed to the subjects on a high resolution video display, both in stereo mode and in mono mode. Half of the mammograms contained a single tumor, ranging from 0.3 to 0.8 cm in maxi­mal diameter. Each …

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A Prototype Computational Phantom To Create Digital Images For Research And Training In Diagnostic Radiology, Charles F. Babbs Nov 1994

A Prototype Computational Phantom To Create Digital Images For Research And Training In Diagnostic Radiology, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Working Papers

Research in the processing, compression, transmission, and interpretation of digital radiographic images require the testing and evaluation of a wide variety of images, varying both in format and in spatial resolution. If receiver operating characteristic (ROC) analysis or a related method is used to evaluate the performance of observers using novel vs. conventional displays, large numbers of test images containing known abnormalities are required. This report describes a convenient, inexpensive, and reproducible source of test images, having any desired resolution and containing precisely defined abnormalities of unlimited subtlety. The images are generated by computing x-ray transmission through mathematically defined, three …

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The Evolution Of Abdominal Compression In Cardiopulmonary Resuscitation, Charles F. Babbs Jan 1994

The Evolution Of Abdominal Compression In Cardiopulmonary Resuscitation, Charles F. Babbs

Weldon School of Biomedical Engineering Faculty Publications

Objective: To review the history of external abdominal compression as an adjunct to cardiopulmonary resuscitation (CPR), tracking the development of five major themes over the course of the 20th century: 1) augmentation of peripheral resistance by physical means, 2) risk of hepatic injury with abdominal compression, 3) counterpulsation vs. sustained compression, 4) the abdominal pump mechanism, and 5) contact compression techniques. Methods: Literature retrieved from successive MEDLINE English-language searches was reviewed with a special emphasis on work and concepts highlighted by participants at the First Purdue Conference on Interposed Abdominal Compression-CPR, September 1992. Results: External abdominal compression of one form …

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