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PubMed2006

Framework for parsing, visualizing and scoring tissue microarray images.

Increasingly automated techniques for arraying, immunostaining, and imaging tissue sections led us to design software for convenient management, display, and scoring. Demand for molecular marker data derived in situ from tissue has driven histology informatics automation to the point where one can envision the computer, rather than the microscope, as the primary viewing platform for histopathological scoring and diagnoses. Tissue microarrays (TMAs), with hundreds or even thousands of patients' tissue sections on each slide, were the first step in this wave of automation. Via TMAs, increasingly rapid identification of the molecular patterns of cancer that define distinct clinical outcome groups among patients has become possible. TMAs have moved the bottleneck of acquiring molecular pattern information away from sampling and processing the tissues to the tasks of scoring and results analyses. The need to read large numbers of new slides, primarily for research purposes, is driving continuing advances in commercially available automated microscopy instruments that already do or soon will automatically image hundreds of slides per day. We reviewed strategies for acquiring, collating, and storing histological images with the goal of streamlining subsequent data analyses. As a result of this work, we report an implementation of software for automated preprocessing, organization, storage, and display of high resolution composite TMA images.

Cytodiagnosis↗

PubMed2003

A rapid speech synthesizing software on a PDA for Japanese with speech impairments.

We developed a Japanese-language, rapid synthesizing software application for use on a personal digital assistant. It has an unrestricted vocabulary and can synthesize words and sentences within 3 s. Eight hundred common sentences and words are preregistered. By touching the first character at the head of a preregistered sentence or word from an on-screen Kana (Japanese alphabet) chart, the user can select the sentence or word to be spoken. Characters on the Kana chart can also be input sequentially. Two Japanese subjects with speech impairments rated the device highly for its portability and quick response. Whereas communication previously had to be done by writing or sign language, it was easy for listeners with or without specialized training in communication with persons with speech impairments to understand the output from this device, making conversation easier which, in turn, improved the quality of life and social activity of these persons with speech impairments.

Asian People↗

PubMed1993

The effect of left ventricular intracavitary volume on the unipolar electrogram.

In order to examine the effects of ventricular distention on the unipolar electrogram (UEG), an isolated rabbit heart modified Langendorff preparation was utilized. Left ventricular (LV) volume was adjusted using ionically permeable (PB = 9 hearts) or ionically impermeable balloons (IB = 4 hearts). LV UEGs, LV end-diastolic pressure (EDP), and LV minor axis dimension (MAD), as measured by ultrasonic transducers, were recorded. Three hundred twenty-five electrograms were digitized and analyzed with custom-designed software. In the PB group, a significant inverse linear relationship was found between UEG amplitude and changes in MAD (P < 0.0001). For each animal, this relationship had an R value > 0.8 and a P value < 0.0001. There was also a significant inverse linear relationship between UEG slope and changes in MAD (P < 0.01). UEG amplitude and slope also exhibited a significant inverse relationship to changes in LV EDP, which were best described by a third order polynomial function. In the IB group, no significant relationship was found between either UEG amplitude or slope and MAD or EDP. In this study, intracavitary volume exerted a profound and significant influence on UEG amplitude and slope. This effect was due to increases in conductive intraventricular volume and not to myocardial stretch.

Animals↗

PubMed2005

Multichannel data acquisition system for mapping the electrical activity of the heart.

BACKGROUND: Details of the electrical conduction pattern of the heart are revealed to the electrophysiologist when multichannel data are used for activation mapping. Commercial electronic systems are available for simultaneous acquisition of many surface electrograms; however, the cost of these systems may be prohibitive and they can be mostly inflexible for adaptation to other research projects. Furthermore, the hardware and software design is often proprietary. In this article we describe the in-house design and implementation of a 320-multichannel acquisition system for animal electrophysiologic research. METHOD AND RESULTS: Several modules comprise this system. The multichannel data are first preprocessed by amplification, filtering, and analog multiplexing. An algorithm for automatic adjustment of signal gains is implemented to maximize the voltage resolution and minimize noise pickup. Signals are then digitized, and sequenced to order the multichannel data and to add markers required for analysis. The digital data are streamed to archival storage media. Additionally, the electrocardiogram (ECG), blood pressure, and stimulus channel signals are stored simultaneously. Selected signals are then displayed in real-time for measurement and analysis and as a check of the system integrity. Examples of multielectrode arrays and surface recordings are provided. Costs for building such a system are estimated. CONCLUSIONS: Multichannel data acquisition systems that are designed and constructed in-house have several advantages over turnkey commercial systems, including the potential for considerable cost savings, flexibility in acquiring data, and the ability to subsequently add additional components.

Analog-Digital Conversion↗

PubMed1998

Nursing model of hospitalization events.

PURPOSE: To provide a model of hospitalization events from a nursing perspective. Hospitalization has become an event of highly technical care coupled with intense nursing care requirements. This proposed model is needed to support clinical nursing research among hospitalized patients. SCOPE: Hospitalization occupying space and time as a discrete event on the health-illness continuum. First developed to provide a framework for a descriptive study, the model shows the factors involved in hospitalization and provides a framework for understanding the nursing care that occurs. Selected results from descriptive research that used patients hospitalized with AIDS as subjects are reported as an example of use of the model. CONCLUSIONS: Research about hospitalization events continues to be critical for the advancement of clinical nursing. This model is presented to provide a conceptual framework for future research.

Clinical Nursing Research↗

PubMedDate not supplied

Creative discharge planning using the electronic medical record.

A multidisciplinary continuous quality improvement (CQI) team at the authors' facility was commissioned and empowered to study and improve communication among the disciplines involved in discharge planning. CQI methods and tools were applied to analyze the process and determine the improvement. The authors of this article describe the use of a customized electronic medical record system to deliver accurate, rapid technology (DART) at their facility. DART was programmed to improve communication among the disciplines by assisting with the referral process. In addition, users are systematically prompted throughout the discharge process to ensure that all aspects are considered and documented.

Aftercare↗

PubMed2006

Comparison of different commercial FFDM units by means of physical characterization and contrast-detail analysis.

The purpose of this study was to perform a complete evaluation of three pieces of clinical digital mammography equipment. Image quality was assessed by performing physical characterization and contrast-detail (CD) analysis. We considered three different FFDM systems: a computed radiography unit (Fuji "FCR 5000 MA") and two flat-panel units, the indirect conversion a-Si based GE "Senographe 2000D" and the direct conversion a-Si based IMS "Giotto Image MD." The physical characterization was estimated by measuring the MTF, NNPS, and DQE of the detectors with no antiscatter grid and over the clinical range of exposures. The CD analysis was performed using a CDMAM 3.4 phantom and custom software designed for automatic computation of the contrast-detail curves. The physical characterization of the three digital systems confirms the excellent MTF properties of the direct conversion flat-panel detector (FPD). We performed a relative standard deviation (RSD) analysis, for investigating the different components of the noise presented by the three systems. It turned out that the two FPDs show a significant additive component, whereas for the CR system the statistical noise is dominant. The multiplicative factor is a minor constituent for all the systems. The two FPDs demonstrate better DQE, with respect to the CR system, for exposures higher than 70 microGy. The CD analysis indicated that the three systems are not statistically different for detail objects with a diameter greater than 0.3 mm. However, the IMS system showed a statistically significant different response for details smaller than 0.3 mm. In this case, the poor response of the a-Se detector could be attributed to its high-frequency noise characteristics, since its MTF, NEQ, and DQE are not inferior to those of the other systems. The CD results were independent of exposure level, within the investigated clinical range. We observed slight variations in the CD results, due to the changes in the visualization parameters (window/level and magnification factor). This suggests that radiologists would benefit from viewing images using varied window/level and magnification.

Equipment Design↗

PubMedDate not supplied

Coordinate transformation as a primary representation of radiotherapy beam geometry.

An approach to both geometric specification of radiotherapy beams and computerized solution of geometric treatment planning problems using coordinate transformations is presented. It is demonstrated that the specification of the geometric relationship of a treatment beam to a patient can be uniquely given by a 4 x 4 coordinate transformation matrix, and that the matrix representation can be translated from (and to) the more conventional machine-based specification of geometry. This approach enables a compact representation of the patient/beam geometry which is independent of the specific labeling conventions of the treatment machine and which can be directly exploited in the solution of treatment planning problems. Beam geometry can be easily described either in terms of the natural degrees of freedom of a therapy machine or in terms of alternative, problem-specific frames of reference. The ability to use these various frames of reference interchangeably allows the designer of treatment design software to present appropriate task-specific user interfaces for arbitrarily complex tasks, and thus reduce the cognitive burden on users of the software.

Humans↗

PubMed1999

Image quality in polypseudophakia for extremely short eyes.

AIM: To evaluate the image quality produced by polypseudophakia used for strongly hypermetropic and nanophthalmic eyes. METHODS: Primary aberration theory and ray tracing analysis were used to calculate the optimum lens shapes and power distribution between the two intraocular lenses for two example eyes: one a strongly hypermetropic eye, the other a nanophthalmic eye. Spherical aberration and oblique astigmatism were considered. Modulation transfer function (MTF) curves were computed using commercial optical design software (Sigma 2100, Kidger Optics Ltd) to assess axial image quality, and the sagittal and tangential image surfaces were computed to study image quality across the field. RESULTS: A significant improvement in the axial MTF was found for the eyes with double implants. However, results indicate that this may be realised as a better contrast sensitivity in the low to mid spatial frequency range rather than as a better Snellen acuity. The optimum lens shapes for minimum spherical aberration (best axial image quality) were approximately convex-plano for both lenses with the convex surface facing the cornea. Conversely, the optimum lens shapes for zero oblique astigmatism were strongly meniscus with the anterior surface concave. Correction of oblique astigmatism was only achieved with a loss in axial performance. CONCLUSIONS: Optimum estimated visual acuity exceeds 6/5 in both the hypermetropic and the nanophthalmic eyes studied (pupil size of 4 mm) with polypseudophakic correction. These results can be attained using convex-plano or biconvex lenses with the most convex surface facing the cornea. If the posterior surface of the posterior intraocular lens is convex, as is commonly used to help prevent migration of lens epithelial cells causing posterior capsular opacification (PCO), then it is still possible to achieve 6/4.5 in the hypermetropic eye and 6/5.3 in the nanophthalmic eye provided the anterior intraocular lens has an approximately convex-plano shape with the convex surface anterior. It was therefore concluded that consideration of optical image quality does not demand that additional intraocular lens shapes need to be manufactured for polypseudophakic correction of extremely short eyes and that implanting the posterior intraocular lens in the conventional orientation to help prevent PCO does not necessarily limit estimated visual acuity.

Astigmatism↗

PubMed2003

Correlation between annual change in health status and computer tomography derived lung density in subjects with alpha1-antitrypsin deficiency.

BACKGROUND: There is increasing recognition that questionnaires of health status and lung density measurements are more sensitive tools for assessing progression of emphysema than forced expiratory volume in 1 second (FEV(1)) and transfer coefficient (KCO). A study was undertaken to investigate prospectively the correlation between annual change in health status and computer tomography (CT) derived lung density in subjects with alpha(1)-antitrypsin deficiency. METHODS: Twenty two patients of mean (SD) age 40.7 (9.2) years with ZZ type alpha(1)-antitrypsin deficiency were investigated at baseline and 30 months later by FEV(1) and KCO, St George Respiratory Questionnaire (SGRQ), and by a spiral CT scan of the chest. CT data of chest images were analysed using software designed for automated lung contour detection and lung density measurements. The density data were corrected for changes in inspiration levels. RESULTS: Changes in lung density, expressed as 15th percentile point or relative area below -950 HU, correlated well with changes in health status (SGRQ total score): R = -0.56, p = 0.007 or R = 0.6, p = 0.003. Neither changes in health status nor changes in lung density correlated significantly with changes in FEV(1) or changes in KCO. CONCLUSIONS: The SGRQ total score (which is a global measure in COPD) and lung density (a specific measure of emphysema) are sensitive to deterioration in patients with alpha(1)-antitrypsin deficiency. This finding may facilitate future studies with new drugs specific for emphysema, a frequently occurring component of COPD.

Adult↗

PubMed2002

Telerehabilitation research: emerging opportunities.

The field of clinical rehabilitation is rooted in the premise that carefully planned and delivered therapeutic intervention enhances patient outcomes. Underlying this statement is a deeper scientific reality: The field exists because biosystems (e.g., tissues, cells, organs, persons) are inherently adaptive and can dynamically change as a function of a sequence of inputs (e.g., exercise, pharmaceuticals). The tools of telerehabilitation help minimize the barrier of distance, both of patients to rehabilitative services and of researchers to subject populations. This enhanced access opens up new possibilities for discovering and implementing optimized intervention strategies across the continuum of care. Telecommunications technologies are reviewed from the perspective of systems models of the telerehabilitation process, with a focus on human-technology interface design and a special emphasis on emerging home and mobile technologies. Approaches for providing clinical rehabilitation services through telerehabilitation are addressed, including innovative consumer-centered approaches. Finally, telerehabilitation is proposed as a tool for reinvigorating the rehabilitative bioengineering research enterprise.

Computing Methodologies↗

PubMed1983

Computer analysis of processor status.

The authors describe the use of a desk-top computer to analyze processor status. Quality control data (sensitometry, densitometry, thermometry, etc.) are collected conventionally. Analysis of the data is subsequently performed using specially designed software. This computer analysis results in a small savings in time and in greatly improved management and presentation of quality control data.

Diagnosis, Computer-Assisted↗

PubMed1994

Assessment of acute pleural effusion in dogs by computed tomography.

We used computed tomography (CT) to examine the effects of infusing 60 ml/kg of saline into the pleural space of four anesthetized paralyzed dogs ventilated with a constant tidal volume at a positive end-expiratory pressure of 0.5 kPa. The dogs were positioned supine, and the thoracic cavity was scanned from apex to base before and immediately after effusate loading. Each CT image was analyzed semi-automatically on a 486 personal computer with custom-designed software. We found that, despite right-side infusion, the effusate was distributed bilaterally no doubt because of the incomplete canine mediastinum. In general, the volume change of the lung was one-third and that of the chest wall was two-thirds that of the total volume infused. Most of the lung volume was contained in the caudal one-third of the lung pre-effusion, and most of the lung volume loss due to effusion was from this same region. Chest wall volume increased and in a more uniform manner post-effusion. The decrease in lung volume resulted in an increase in the mean density of the lung and an increase in its vertical density gradient as the lung was lifted upward toward the sternum by the effusate. The lung lost vertical height while the chest wall increased both its vertical and lateral dimensions after effusate loading. These results suggest that expansion of the chest wall helps preserve lung volume in the presence of acute pleural effusion. We have also demonstrated that CT is a useful tool for assessing changes in volume, shape, and density of the respiratory system.

Animals↗

PubMed2006

Advances in magnetic resonance imaging of lung physiology.

This review presents an overview of some recent magnetic resonance imaging (MRI) techniques for measuring aspects of local physiology in the lung. MRI is noninvasive, relatively high resolution, and does not expose subjects to ionizing radiation. Conventional MRI of the lung suffers from low signal intensity caused by the low proton density and the large degree of microscopic field inhomogeneity that degrades the magnetic resonance signal and interferes with image acquisition. However, in recent years, there have been rapid advances in both hardware and software design, allowing these difficulties to be minimized. This review focuses on some newer techniques that measure regional perfusion, ventilation, gas diffusion, ventilation-to-perfusion ratio, partial pressure of oxygen, and lung water. These techniques include contrast-enhanced and arterial spin-labeling techniques for measuring perfusion, hyperpolarized gas techniques for measuring regional ventilation, and apparent diffusion coefficient and multiecho and gradient echo techniques for measuring proton density and lung water. Some of the major advantages and disadvantages of each technique are discussed. In addition, some of the physiological issues associated with making measurements are discussed, along with strategies for understanding large and complex data sets.

Helium↗

PubMed2005

Changes in serum proteomic patterns by presurgical alpha-tocopherol and L-selenomethionine supplementation in prostate cancer.

BACKGROUND: Evidence of the chemopreventive effects of the dietary antioxidants alpha-tocopherol (vitamin E) and l-selenomethionine (selenium) comes from secondary analysis of two phase III clinical trials that found treatment with these antioxidants reduced the incidence of prostate cancer. To determine the effects of selenium and vitamin E in blood and prostate tissue, we undertook a preoperative feasibility study complementary to the currently ongoing Selenium and Vitamin E Cancer Prevention Trial. METHODS: Forty-eight patients with clinically localized prostate cancer enrolled on this 2 x 2 factorial design study were randomized to take selenium, vitamin E, both, or placebo for 3 to 6 weeks before prostatectomy. Sera were collected from patients before and after dietary supplementation. Thirty-nine patients were evaluable, and 29 age-matched disease-free men served as controls. Mass profiling of lipophilic serum proteins of lower molecular weight (2-13.5 kDa) was conducted, and mass spectra data were analyzed using custom-designed software. RESULTS: Weighted voting analyses showed a change in sera classification from cancerous to healthy for some patients with prostate cancer after dietary intervention. ANOVA analysis showed significantly different treatment effects on prediction strength changes among the four groups at a 95% confidence level. Eliminating an outlying value and performing post hoc analysis using Fisher's least significant difference method showed that effects in the group treated with the combination were significantly different from those of the other groups. CONCLUSION: In sera from patients with prostate cancer, selenium and vitamin E combined induced statistically significant proteomic pattern changes associated with prostate cancer-free status.

Analysis of Variance↗

PubMed1997

Bigated transcranial Doppler for the detection of clinically silent circulating emboli in normal persons and patients with prosthetic cardiac valves.

BACKGROUND AND PURPOSE: Detection of clinically silent circulating microemboli by transcranial Doppler sonography is now being widely investigated in the hope of identifying patients at increased risk for stroke. Automatic detection by bigated Doppler, which uses sampling from two different depths in the artery under study and considers the motion of the embolus, may help to define "periods of interest" that can be evaluated off-line. METHODS: In 12 normal volunteers and 10 patients with prosthetic aortic valves, we performed 1-hour recordings from one middle cerebral artery. In the normal subjects, we produced additional artifacts to use them as false-positives. Detection of microemboli was done off-line from digital audiotapes by an experienced blinded investigator (used as the gold standard) and was compared with on-line detection using specially designed software. RESULTS: With the setting used, 91.5% of all recorded artifacts could correctly be identified as such with the software. Embolic signals were detected by the software with a specificity of 59.9% and a sensitivity of 74.3%. CONCLUSIONS: Bigated Doppler adds a new dimension to the definition and detection of microembolic signals. It constitutes an important step forward toward automatic screening of stroke-prone patients. Assessing on-line periods of interest during the recording and going over the recorded data again off-line helps to save time for the discrimination of embolic signals from both the normal Doppler spectrum background and artifacts.

Aged↗

PubMed2000

Role of the heart in the loss of aeration characterizing lower lobes in acute respiratory distress syndrome. CT Scan ARDS Study Group.

In the acute respiratory distress syndrome (ARDS), lower lobes appear essentially non-aerated in contrast to upper lobes whose aeration can be preserved in some patients. The aim of this study was to assess the mechanical compression exerted by the heart on lower lobes in patients with ARDS. Fourteen healthy volunteers and 38 patients with ARDS free of left ventricular failure were studied. Cardiorespiratory parameters were recorded and the cardiac dimensions, the pressure exerted by the heart on subjacent lower lobes, and the gas tissue ratio of lower lobes in the supine position were measured using computer tomography and Lungview, a specifically designed software. In patients with ARDS, the heart was larger and heavier than in healthy volunteers. The enlargement of the heart was mainly related to a left cardiac protrusion and the pressure exerted by the left heart on the lower lobes was higher in patients with ARDS than in healthy volunteers (8 +/- 3 g. cm(-)(2) versus 6 +/- 1 g. cm(-)(2), p < 0.01). As a consequence, the faction of gas represented 62% of the left lower lobes in healthy volunteers and 12% only in patients with ARDS. The present study demonstrates that apart from the already known anteroposterior and cephalocaudal gradients of pressure depending on the lung weight and abdominal pressure, the heart plays an important role in the dramatic loss of aeration characterizing lower lobes of patients with ARDS lying in the supine position.

Adult↗

PubMed1995

Does ischemia occur with panic attacks?

OBJECTIVE: The authors examined ambulatory ECG changes during panic attacks in patients with panic disorder. METHOD: Ten otherwise healthy women with panic disorder and complaints of chest pain during panic attacks underwent a symptom-limited exercise test on a treadmill and then wore an ambulatory ECG monitor with software designed to detect and record ischemic events and used a hand-held computer for up to 6 days. RESULTS: Eight of the women had panic attacks while using the hand-held computer and the ECG monitor. No ischemic events occurred during any of the exercise tests. Twelve tachycardiac events occurred during panic attacks and 84 tachycardiac events occurred that were not associated with panic attacks. Panic attacks were associated with significantly more symptoms than were tachycardiac episodes. CONCLUSIONS: In this group of otherwise healthy women with panic disorder and chest pain, ambulatory ischemic changes were not recorded during panic attacks.

Adolescent↗