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At least 811 records · Page 45Linked to original sources
PubMed1975

Functional imaging of intrarenal blood flow using scintillation camera and computer.

In order to obtain spatial distribution of an index for regional blood flow at each element on a scintigraphic image of the kidney, we attempted the construction of the so-called functional image. After injecting a single bolus of 133Xe into a renal artery by means of a catheter, this objective was accomplished using digital computer processing for a sequence of scintillation camera recordings of the following washout process from the kidney. This is expressed in a form of matrix of disappearance rate constant. Calculation for the rate constant, the flow index of the functional image, was done using either the least squares (LS) method or height-over-area (H/A) method. Although the former method was considered to be theoretically suitable without undue participation of background activities, the latter was preferred because of stable results for image construction. On reviewing the functional image thus obtained from 22 patients representing a variety of renal diseases, the H/A gave specific information concerning regional distribution of the perfusion integrity mainly related to the cortical part of the kidney. This is often difficult to accomplish utilizing the conventional method of compartmental analysis of the xenon washout curve or selective renal angiography.

Angiography↗
PubMed1977

[Computer assisted heart and circulation analysis in experimental septic shock (author's transl)].

Developping a model of shock applying to the clinical manifestation is necessary to investigate the pathogenesis of septic shock and to identify the letality causing organ. Perhaps the hyperkinetic syndrome may play an important role. The extensive experimental data is processed by a digital computer. Explanations are given for the experimental apparatus and the structure of the Fortran-program.

Animals↗
PubMed1983

Analogue computation of indices of contraction from regional measurements in intact hearts.

Computation of indices of regional myocardial contractility such as the shortening, or the work done by or on a segment of myocardium in a single cardial cycle is tedious to perform manually, and complex interfacing and software is needed for digital computation. We describe the principles of an on-line, analogue device to perform these computations . The accuracy of the machine is demonstrated, and examples of the uses of the devices are given.

Animals↗
PubMed2005

[Measurement of morphological parameters of Cryptosporidium muris oocysts by digital image processing technology].

OBJECTIVE: To establish and analyze the morphological parameters of the oocysts of Cryptosporidium muris for defining their morphological change. METHODS: Oocysts were collected from KM mice (immunodepressed by dexamethasone for 10 days) and examined with modified acid-fast staining. Images of 1 190 oocysts were acquired by photograph system. The length, width, perimeter, area and equivalent diameter of the oocysts were obtained by computer digital image processing system and analyzed by SPSS software (Version 11.0). RESULT: The average length of the oocysts was 5.93 microm, ranging from 3.36 microm to 8.51 microm in 95% confidence interval of them. The average width was 4.96 microm, ranging from 3.26 microm to 6.66 microm in 95% confidence interval of them. The average perimeter was 18.03 microm and the average area was 16.08 microm2. CONCLUSION: Data obtained from the computer system are objective and precise, offering scientific foundation for measuring the oocysts and for identifying Cryptosporidium spp.

Animals↗
PubMedDate not supplied

Automation of measurements and interventions in the systematic care of postoperative cardiac surgical patients.

Since July of 1967, a computer-based system has been employed in the observation and treatment of 8500 patients following cardiac surgical procedures. Of the 12 beds in the University of Alabama Hospital Cardiac Surgical Intensive Care Unit, 10 are equipped with biomedical instrumentation interfaced with digital computer systems. These systems perform the automatic acquisition, display, storage, retrieval, and charting of measurements; computation and evaluation of acid-base balance from manually entered blood gas data; analysis of the data for the detection and treatment of impaired cardiac performance; automatic control of blood infusion and vasodilating agents by closed-loop feedback control techniques; hourly evaluation of chest tube drainage patterns to detect excessive blood loss in the early hours following operation; and computation of the infusion rate (ml/hr) of pharmacologic agents according to a specified dosage (microgram/kg/min). Automatic control of left atrial pressure by blood infusion has been applied to 8000 patients during the past 10 years. Regulation of mean arterial pressure by computer-controlled infusion of vasodilating agents has been performed in 400 patients in the last 2 years. The use of the system has contributed to the reduction of patient time spent in the unit to 24 hours or less for the majority of the patients.

Cardiac Surgical Procedures↗
PubMedDate not supplied

Computer-aided control of water activity for lipase-catalyzed esterification in solvent-free systems.

A computer system for on-line monitoring and control of the water activity (a(w)) in solvent-free media has been developed. The performance of this system was investigated by carrying out the lipase-catalyzed esterification of n-capric acid with n-decyl alcohol. A humidity sensor measured the relative humidity in the reactor headspace, which was then transmitted electrically to a digital computer that was used as a feedback controller. The water activity control was achieved by sparging either humidified air or dried air through the reaction medium at a flow rate determined by the digital feedback controller. The use of humid air and dry air for a(w) control made it possible to induce a larger a(w) gradient and thereby higher water transfer rate. As a result, the water activity quickly reached the desired a(w) values. We tested whether water activity in the reaction medium can be monitored by measuring relative humidity in the headspace. When the water activity in the liquid phase was determined from measurements of water content in the medium and compared to that measured directly with the humidity sensor, the a(w) in the reaction medium did not differ significantly from that in the headspace. This indicates that there is a near-equilibrium between the liquid medium and the exit air stream. Water activity was also successfully maintained close to the set point despite the massive production of water during the esterification process. Thus, the control system developed in this study is particularly useful for systems where large amounts of water are produced and where conventional methods make it difficult to control water activity as a result of a low water transfer rate. The effects that computer control of the water activity had on the reaction rate and yield were also examined. The reaction yield was significantly improved with water activity control. The conversions obtained at 28 h without and those with water activity control were 70% and 96%, respectively. In addition, from the fact that the final yields increased with decreasing a(w), computer-aided water activity control was performed with a set-point change. By controlling a(w) at 0.55 during initial reaction phase, followed by a step change of a(w) from 0.55 to 0 after 11 h of reaction, it was possible to enhance the final conversion to 100%.

Catalysis↗
PubMedDate not supplied

Baseline: a computer method of calculating baseline in fetal heart rate recordings.

'Baseline' estimation is of fundamental importance in both visual and numerical analysis of fetal heart rate recordings, even though the baseline itself is in reality an imaginary line. Here we describe a linear method of estimating baseline in fetal heart rate recordings. The method is easy to implement on a digital computer, and is capable of precise mathematical analysis. Non-linear methods, on the other hand, introduce unpredictable and non-quantifiable statistical bias, and are best avoided.

Computers↗
PubMed1980

Edge enhancement of computed tomograms by digital unsharp masking.

Edge enhanced images can be produced on existing commercial computed tomographic equipment by a method called "digital unsharp masking" without any expense or computer software development. This technique permits display of anatomic areas having an extremely wide range of densities, while making edge detail more apparent.

Humans↗
PubMedDate not supplied

Mathematical model of the proliferation cycle of lymphoblastic leukemia cells.

In the paper a system of equations is described, which enables computation of the mean number of leukemic cells in the blood as a function of time. After formulation of the problem in the form of cybernetical model, the equations are derived. Then the results of modeling obtained with the aid of a digital computer are described. The paper concludes with short summary.

Cell Cycle↗
PubMed1971

Doctors as decision-makers: a computer-assisted study of diagnosis as a cognitive skill.

When viewed as a sequence of decisions clinical diagnosis becomes amenable to detailed investigation in terms of standard statistical concepts. A study of six clinicians diagnosing identical sets of cases of non-toxic goitre is used to illustrate an objective technique for studying the diagnostic process with the aid of a digital computer. Considerable variation in clinicians' routes to correct diagnosis is shown when these routes are compared in detail by five statistical measures related to the effective use of the information available to the clinicians. For rapid analysis of diagnostic skill two visual methods are presented. These can be developed for teaching undergraduates the interpretative skills involved in diagnosis and for studying such skills in experienced clinicians.

Computers↗
PubMed1979

RADIONUCLIDE COMPUTED TOMOGRAPHY: APPLICATIONS IN CARDIOVASCULAR DISEASE.

Tomography is an imaging modality in which information in one plane is displayed in focus while information from overlying and underlying planes is either blurred or eliminated. As a result, there is an improvement in the contrast of structures in the plane of interest. Computerized axial tomography (CAT) is an imaging modality in which a digital computer mathematically reconstructs the image of a plane or section from data collected perpendicular to the axis of that plane. The axis of the plane and the patient's long axis usually coincide so that the reconstructed images reveal transverse sections. In recent years, two types of computed tomography in medical imaging have generated a great deal of interest. These are X-ray transmission and radio-nuclide emission computed tomography.

Journal Article↗
PubMed1979

Apperceptive signals demonstrating the dynamic disturbance of myocardial ischemia.

Analog pressure signals (catheter-tip manometers) from the left atrium, left ventricle, and aorta and a flow signal from the arota were obtained in 25, open-chest, anesthetized dogs in which 115 episodes of ischemia were produced in an area of the left ventricle subtended by the distal left anterior descending coronary artery and its last major diagonal branch. The left ventricular pressure and its first derivative (dP/dt) were displayed as an X-Y loop. The character of this loop went through a unique series of dynamic changes in 110 of the 115 ischemic episodes, indicating that this is a useful tool for monitoring myocardial ischemia. Spectrum pairs of the above signals were analyzed with digital computational transfer functions in 14 ischemic episodes of three experiments and preliminary assessment reveals unique pole and zero changes in many pairs during each episode which also may prove to be a useful indicator of the hemodynamic disturbance incurred during myocardial ischemia.

Analog-Digital Conversion↗
PubMed1997

Evaluation of a training program for persons with SCI paraplegia using the Parastep 1 ambulation system: part 5. Lower extremity blood flow and hyperemic responses to occlusion are augmented by ambulation training.

OBJECTIVE: To test whether 12 weeks of exercise conditioning using functional neuromuscular stimulation (FNS) ambulation alters the resting lower extremity blood flow and hyperemic responses to vascular occlusion in subjects with paraplegia, and to determine whether an association exists between limb flow and lower extremity fat-free mass. DESIGN: Pretest, posttest. SETTING: Academic medical center. PARTICIPANTS: Subjects with chronic neurologically complete paraplegia. INTERVENTION: Thirty-two sessions of microprocessor-controlled ambulation using electrically stimulated contractions of lower extremity muscles and a rolling walker. OUTCOME MEASURES: Subjects underwent quantitative Doppler ultrasound examination of the common femoral artery (CFA) before and after training. End-diastolic arterial images and arterial flow-velocity profiles obtained at rest and after 5 minutes of suprasystolic thigh occlusion were computer-digitized for analysis of heart rate (HR), CFA peak systolic velocity (PSV), CFA cross-sectional area (CSA), flow velocity integral (FVI), pulse volume (PV), and CFA (arterial) inflow volume (AIV). RESULTS: Significant effects of training on CSA (p < .0001), FVI (p < .05), computed PV (p < .001), and computed AIV (p < .01) were observed. Resting HR was lower following training (p < .05). The change for resting PSV approached but did not reach significance (p = .083). Analysis of postocclusion PV and AIV showed significant effects for conditioning status (p values < .01), postcompression time (p values < .0001), and their interaction (p values < .01). At 1 minute after occlusion, the posttraining AIV response was 78.2% greater in absolute magnitude and 17.4% more robust when expressed as a percentage change from its resting value than before training. Significant correlations were found between thigh fat free mass and both AIV and PV (p values < .05). CONCLUSION: Exercise training using FNS ambulation increases the resting lower extremity AIV in individuals with paraplegia and augments the hyperemic response to vascular occlusion. Improved posttraining blood flow is attributable both to vascular structural changes and upregulation of vascular flow control mechanisms. Limb mass is associated with the volume of arterial blood flow.

Adult↗
PubMed1983

Computer analysis of the non-angular parameters of the QRSsE loop and orthogonal lead QRS characteristics in necropsy-verified normal dogs.

The canine modification of the Axial lead system of McFee and Parungao was used to record the VCG from 38 necropsy-verified normal dogs. Characteristics of the QRSsE loop were analyzed by a FORTRAN program on the IBM 360/75 digital computer. The following non-angular parameters were characterized for the normal dog: loop areas in the frontal, sagittal, and transverse planes; time duration of QRS; time integral of QRS; peak spatial magnitude; spatial velocity; eigenvalues and eigenvectors. It was shown that the normal QRSsE loop was extremely planar, but of variable length and width. Vector lengths at nine points in each plane were determined. Extreme absolute and percentage variation existed in all vector length parameters. The orthogonal lead characteristics were described. A consistent finding was a Q wave in lead Vx in all subjects. An S wave was present in this lead in 50% of the dogs. In lead Vy a Q wave was found in 81.6% of the dogs and an S wave was present in 94.7%. In contrast to the consistency of the angular parameters found in this same group of dogs which was reported earlier, the non-angular parameters and orthogonal characteristics could not generally be defined over small ranges.

Animals↗
PubMedDate not supplied

Emerging technology: remote analysis of traumatic musculoskeletal radiographs transmitted by electronic mail.

OBJECTIVES: To determine whether remote analysis of radiographs via electronic mail (e-mail) had an impact on treatment decision-making. DESIGN: Prospective. SETTING: Level I trauma center. PATIENTS/PARTICIPANTS: Twenty-five cases randomly selected from previous emergency room consultation. INTERVENTION: Textual descriptions obtained from emergency medicine physicians were compared with computer-digitized images of radiographs sent via e-mail and with the actual radiographs. Four board-certified orthopaedic surgeons reviewed all three forms of data to determine fracture diagnosis and treatment plans. MAIN OUTCOME ASSESSMENT: Diagnosis and treatment plans were obtained via written questionnaire after review of each group of data (textual, digitized image, and actual radiograph). Results were then compared across groups to determine whether digitized images were better than textual descriptions and equivalent to actual radiographs. RESULTS: Statistical analysis revealed a significant improvement in the frequency of correct diagnosis and treatment planning when digitized images were used (91 percent) compared with textual descriptions alone (48 percent) (p < 0.001). The difference in correct diagnosis and treatment plans between digitized images and actual radiographs was not statistically significant (p = 0.27). CONCLUSION: Digitized radiographs sent via e-mail can significantly improve accuracy of diagnosis and treatment compared with a simple verbal description.

Computer Communication Networks↗
PubMed1975

A computerized aid to Ball pelvimetry.

A computer program is presented that will generate a table of capacities and volumes for use with the Ball technique for cephalopelvimetry. The technique of Ball pelvimetry is reviewed and directions for use are described. This table may be produced on any medium or large-scale digital computer equipped with a FORTRAN compiler and a standard page printer. Its use eliminates many errors inherent in previous methods of volume computation. Physician acceptance has been excellent.

Cephalometry↗
PubMed1993

Overview of imaging science.

The traditional disciplines of science are grounded in the observation and measurement of object properties. Recent advances in digital computer technology have spawned numerous computer-based imaging systems that extend the range of observation and measurement into realms that would otherwise be inaccessible. More importantly, the same set of principles, concepts, strategies, and methods may be used to address the generic issues involved in the production and use of all digitized images. Recognition of this fact is giving rise to the new discipline of imaging science, with its own intellectual agenda.

Journal Article↗
PubMed2006

Comparison of active motor items in infants born preterm and infants born full term.

PURPOSE: The study was designed to compare active motor items at term age of infants born very preterm, very low birth weight (VPT-VLBW) and without impairments with infants born full-term (FT) and healthy and to evaluate a method of assessment using video recordings and computer software. METHOD: Video recordings of head lag and head righting on pull to sit, head control in sitting, and hip flexion in prone were obtained at term age for 29 infants born VPT-VLBW and 22 infants born FT. Motor items were analyzed using digitizing computer software. RESULTS: Infants born VPT-VLBW had less head lag on pull to sit than infants born FT, p = 0.005. No other differences were found for the remaining motor items. The method of assessment demonstrated high intrarater reliability (intraclass coefficient correlation (3,1) = 0.77-0.997). CONCLUSIONS: Infants born VPT-VLBW who are at "low risk" performed at term age similarly to healthy infants born FT on four active motor items. The reliability of the measurement method supports the method's further development.

Child Development↗