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Good pancreas imaging is difficult to achieve even if a computer is applied. The special computer program proposed here was developed to optimize the results and to minimize the operator interaction with the data processing system.
A digital computer system is described which allows the real-time processing of all physiological signals obtained during a heart catheterization procedure and which makes all relevant results and informations available immediately during the investigation. In addition, special electronic units and programs have been developed in our institution for the automated extraction of morphological criteria from biplane angiocardiograms. Thereby right and left ventricular volume, shape and contraction pattern can be quantitated and used to characterize the performance of the heart as muscle and pump in physical terms. Recently, complete digital processing of videoangiocardiograms has been achieved in a stroboscopic mode, each videofield in real time. Application of image enhancement, subtraction, integration and restoration techniques leads to a fundamentally improved angiocardiographic image quality for a given amount of injected contrast material. Based on eight years of experience with digital computer application in pediatric cardiology, computer technologies are considered likely to become the method of choice in the future.
The current applications of neural networks to in vivo medical imaging and signal processing are reviewed. As is evident from the literature neural networks have already been used for a wide variety of tasks within medicine. As this trend is expected to continue this review contains a description of recent studies to provide an appreciation of the problems associated with implementing neural networks for medical imaging and signal processing.
A new method of studying regional lung functions using 133Xe and the computer-assisted scintillation camera is described. The method and the computer processing give details of the distribution of 133Xe during perfusion and ventilation and also measures of lung function. Some cases are described in detail, and the clinical significance of the method was confirmed in 45 cases.
In this work a general purpose image processor is described, which takes into account the special features and the various requirements for analysing images in nuclear medicine. A new approach for system structure involving encoding and representing medical images is given. This encoder, which is part of the image processor, is efficient especially for long-term storage and for certain pattern recognition in medical imaging. In this processor a statistical package is incorporated for collecting medical statistics using the acquired patient data. This information is used together with the encoder for an automated diagnostic system.
A new system by which paper-recorded EEG can be converted to computer treatable digital data was developed. It consists simply of an image scanner and a microcomputer. The performance of the system was evaluated and found to perform well in data reconstruction. The system makes it possible to apply various computer analyses to EEGs recorded on paper.
In this newly developed method, the ultrasonic diagnosis has become quantitative. The data will remain quantitative so far as an image storage tube is used. With the conventional storage type CRT, it is impossible to memorize the reflected echo signals of different strength levels. But with our method, it becomes possible to memorize the images according to individual levels. By the direct digitalization of the ultrasonic echo images, more information is obtained from the reflected echo signals. By processing the original information with a computer, more accurate diagnosis is possible. It is hoped and believed, that this computer aided ultrasonic examination, with single scan display in colour or black and white, will further promote ultrasonic diagnosis in future.
A practical protocol for evaluating and monitoring head injured patients has been presented. It has been stressed that monitoring is an ongoing process which begins with the initial evaluation and continues throughout the patient's hospital stay. The level of monitoring and thus the parameters to be monitored are determined on an individualized basis according to the patient's clinical status and his level of stupor and coma. It has been suggested that for mild head injuries, adequate monitoring includes periodic evaluation of the neurological status and vital signs; but the more severely injured patients require extensive and frequent monitoring of a large number of clinical and physiological parameters. Among the many parameters, the continuous monitoring of ICP and the respiratory system are perhaps the most useful indicators of the patient's condition. Several methods for continuous ICP monitoring which are readily adaptable to most neurosurgical practices have been discussed. These include the intraventricular catheter, subarachnoid screw, and the closed Rickham reservoir connected to a ventricular catheter. In our institution, the Rickham reservoir has been used to monitor ICP and at the time of this report, satisfactory ICP recordings have been obtained in 27 of 30 head injury patients. Although this method requires a small surgical procedure, we believe that the decreased incidence of infection, the rapid access to ventricular fluid, and its potential for long term monitoring justify its use. Suggestions for monitoring other physiological parameters have also been presented. Particular emphasis has been placed on the management of infants and children with head injuries. The clinical entity of chronic subdural hematoma in infants and children has been used to illustrate the value of ICP monitoring as a guide to further treatment. Finally, we have briefly discussed the place of computers in day to day patient care, research, and monitoring.
A feasibility study is described to provide quantitative texture measures to distinguish between normal lung, alveolar infiltrates and interstitial infiltrates. Advanced computer imaging technology and decision making processes were applied to distinguish between these textural patterns. The results, based on computer extracted quantitative measures, show an excellent separation of the three classes considered with 95% accuracy in the training phase and 90% accuracy in the testing phase.
An overview of Bayesian statistical decision theory is presented in the tutorial spirit. A section on fundamental principles is followed by selected applications of the Bayesian approach to parameter estimation, pattern recognition, image processing, computer-aided medical diagnosis, optimal diagnostic test selection, and radiotherapy treatment planning.
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The mean retinal venoarterial width ratio in 100 healthy subjects was measured with a PZO stereoscopic microscope equipped with a calibrated ocular and with an automatic digital image transformer coupled with an ODRA 1204 computer. The mean value was estimated as equal to 1.21 with an SD of 0.071. The same study was performed in 75 atherosclerotic patients and 75 patients with essential hypertension. In the first group the mean retinal venoarterial width ratio amounted to 1.51 (SD 0.054), while in the second one it was equal to 1.53 (SD 0.079).
Synthetic aperture imaging using a catheter based, circular phased array providing high resolution, dynamic focusing has been explored. Due to the high input impedance and low signal-to-noise ratio (SNR) of a classic single element synthetic aperture system, multi-element synthetic aperture processing has been proposed with SNR improvement of about 8 dB for a 33 element aperture. Reconstruction in this case uses an optimal filtering approach based on minimizing the mean square error between filter output and desired beam pattern. This approach, however, does not directly control both mainlobe beamwidth and sidelobe levels. To overcome this problem, a Lagrange based filter design technique has been developed that not only satisfies the minimum energy criterion, but also constrains sidelobe levels under a certain threshold. The new technique provides better spatial and contrast resolution. Both the mathematical formulation and simulation results are presented.
A mathematical process has been devised which can utilize full clinical data of symptoms and signs, neuroradiological procedures, EEG and isotope scanning to predict the site and pathological process in a patient presenting with disturbance of central nervous system function. The work is a further expansion and modification of the computer program described by Du Boulay and Price (1968).
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.
In order to refine the diagnostic possibilities of the radionuclide renal study in transplanted patients and to compensate for the nonspecificity of the 131I-hippuran study in some situation, 99mTc-DTPA WAS USED SIMULTANEOUSLY FOR IMAGING AND TIME-ACTIVITY CURVES. For these curves to be significant, appropriate background subtraction had to be made with a simple computer-processing method. The results obtained have shown that it is possible to distinguish marked acute tubular necrosis from milder degrees, thus affording a prognostic index in the immediate postoperative period, when the hippuran data are often nonspecific. Further, the diagnosis and follow-up of acute rejection episodes can be improved by the DTPA processed curves. Although these curves when examined individually do not show a specific pattern for rejection, they may reveal striking evolutionary changes when compared to the previous studies, even when the hippuran curves are unchanged. The physiologic basis for the differences between the two time-activity curves may be related to the differential handling of the two radiopharmaceuticals by the kidney.
Computer techniques as introduced into clinical nuclear-medicine 12 years ago, were first exclusively used for scintigraphic purposes. Through the development of a comprehensive pilot system for nuclear medical data processing on the basis of two Siemens Process control computers it could be demonstrated, that besides of scintigraphy there are also other important fields for computer application, e.g. in function diagnostics and therapy planning.
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