PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Radiographic Image Interpretation, Computer-Assisted”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 145 records · Page 8Linked to original sources
PubMed1991

[Digital luminescence radiography. Part 1: Basic principle, technical execution and clinical use].

Digital luminescence radiography (DLR) is a new technique in projection radiography, which enables the production of plain X-ray images and motion tomographies with high quality, and is suitable for digital image management. With this procedure the X-ray image produced by conventional roentgen devices is temporarily stored on a reusable photostimulable storage phosphor screen which is characterized by a wide dynamic range. A laser beam scans the exposed phosphor screen and recovers the stored X-ray information as photostimulated luminescence radiation. A photomultiplier converts the emitted light into electrical signals. After normalization and digitization the signals are transmitted to an image processor. The stored digital image can be individually processed and displayed, digitally archived or transferred to any location. The technique is described in two following papers. Part 1 covers the basic principle of the system and the technical implementation of the data acquisition with its advantages and disadvantages as compared with conventional film/screen radiography.

Equipment Design↗
PubMed1991

[Roentgen diagnosis of pulmonary complications following allogeneic bone marrow transplantation--application of and experience with digital luminescence radiography].

Pulmonary complications exercise a decisive influence on the prognosis of leukaemia patients after bone marrow transplantation. Very early diagnosis is a mandatory prerequisite to successful therapeutic intervention. Of great importance besides the clinical findings and bronchoalveolar lavage is the analysis of the x-ray morphology of pneumonic infiltrates to narrow down the differential diagnostic spectrum. Since the patients are at high risk of infection, they are under isolated care, so that x-ray examinations can only be performed by means of projection radiography using mobile units. Due to these difficulties in performing relevant radiography the required optimal and constant image quality cannot be achieved by means of conventional x-ray film, so that very early detection of pulmonary complications is not always possible. The use of digital luminescence radiography (DLR) with luminescent storage foils enables a highly constant and hence comparable image quality thanks to increased image dynamics, a larger area of the examined object, and histogram evaluation of the image data for determining the optimal parameters for assessment. In addition, details can be better identified to supply answers to specific questions, because the image can be reprocessed to select relevant image parameters by monitoring. Pulmonary complications in 86 patients were analysed retrospectively. These patients had received an allogeneic bone marrow transplant for acute myeloic leukaemia, after they had been treated with high-dose radio-/chemotherapy. The x-ray morphology, clinical and sometimes autopsy findings were correlated with the occurrence of pulmonary complications subsequent to bone marrow transplant.

Adolescent↗
PubMed1991

[Computer-assisted report generation and image transmission in bedside chest x-rays in intensive therapy units].

Since a few years ago, in our department the bedside chest X-rays of intensive care patients have been reported by means of a computer program which has also storing function. This computer program is a guideline for the radiologist and is organized in pages having a logical sequence. The program has proved very useful in learning the correct reporting of bedside chest X-rays. The nosographic data of the patients, the ventilatory and the technical data are stored for a better clinico-radiological correlation. The last four reports are displayed on the monitor to better understand the patient's history. The other reports become part of a "historical" archive. Most important is the cooperation with the referring physician: to make the most of it, a system has been implemented which sends the images from the Radiology Department to Intensive Care. The images are filmed with a camera and then digitalized on 1024 x 768 matrix with 16 million colors and 256 gray levels. Each workstation is composed of: AT286 computer with 60-MB hard disk, hardware or the digitalization and compression of images, a high-resolution monitor, an intercommunication system, and a modem. It is possible to zoom on the images, but a close-up on the image with the camera is better for improved spatial resolution. The images are stored on the hard disk: each image requires 3M bytes, but it can be compressed down to 25:1 with no detail loss. The images are transmitted via modem in at least 20 seconds/image. More images can be sent out-line. During transmission, it is possible to talk by the intercommunication system, pointing out structures on the monitor or drawing objects on both sides of the system. In our experience, image quality is good. We are therefore considering extending the network to other Departments and making the transmission of images of pathologic specimens possible. The natural evolution of this system is the teleconsult.

Computer Communication Networks↗
PubMed1991

[Digital thoracic radiography--a comparison of digital and analog imaging techniques].

New analog and digital imaging techniques for the chest became available in recent years. In this study conventional film/screen radiography was compared with slit technique ('AMBER'), storage phosphor radiography and digital image intensifier radiography by phantom exposures and patient examinations. Because of its low spatial resolution, quality of digital image intensifier radiography was insufficient for chest imaging. The slit technique demonstrated the highest image quality, especially in the fields of the mediastinum and the thoracic wall. In comparison to conventional film/screen radiography, storage phosphor radiography had advantages in the mediastinal field. Digital techniques are connected to new possibilities of image post-processing, storage and transfer. For difficult conditions of exposure (emergency unit) over- or underexposed images can be avoided by these new digital techniques. The combination of slit- and storage phosphor-technique did not increase image quality.

Analog-Digital Conversion↗
PubMed1991

Automated selection of clinical data to support radiographic interpretation.

Modern computerized hospital information systems can store much of the clinical information required for patient care. In some settings the amount of this information is great enough to interfere with its efficient use. Supplying information in support of radiographic interpretation provides an example of this problem. We describe an automated process that abstracts select data from a clinical database and creates a report recounting salient facts designed to assist the radiologist in interpreting the chest x-ray. The reporting system selects data using a combination of expert systems technology and information theory. It produces a brief summary of relevant clinical data. The original version of this process required run-time use of expert systems techniques that were time-prohibitive in the clinical setting. Through the use of pre-compiled tables of finding specific information contents we have reduced the time requirement to a point where the applications will soon be clinically feasible.

Databases, Factual↗
PubMed1991

Digital subtraction radiography for the assessment of changes in peri-implant bone density.

Digital subtraction radiography is proposed as a potential diagnostic tool for implant research and patient monitoring. Examples of the application of this technique are given observing peri-implant density changes during the early healing phase and during ligature-induced peri-implantitis in an animal model. Additional cases document the loss of peri-implant bone density associated with an infection and increase in density caused by remodeling after functional loading of an implant with a single crown. Digital subtraction radiography might be one of the most sensitive noninvasive methods for assessing subtle density changes in peri-implant tissues, providing additional diagnostic information on implant tissue integration and maintenance.

Alveolar Bone Loss↗
PubMed1991

Automated microdensitometric quantification of bone ingrowth into porous implants.

The aim of this study was to develop a technique of automated histometric quantification of bone ingrowth into porous implant bodies that minimizes errors of volume determination arising from the section thickness of histologic specimens. A theoretical and experimental deduction is provided for the calculation of implant and bone layer thicknesses from the grey levels of microradiographs made from thick-section specimens. The presented method allows rapid raising of large amounts of histometric data when a computer-aided video system is available. A histologic preparation of specimens that permits the spatial reconstruction of the examined implant volume and analysis of three-dimensional distribution of bone ingrowth is suggested.

Absorptiometry, Photon↗
PubMed1991

[Application of computerized teleroentgenographic analysis in orthodontic diagnosis].

The rapid advancement of electronics and availability of inexpensive personal computers have resulted in analytical programs for metric evaluation and graphic presentation of cranial roentgenograms and made it possible to predict craniofacial growth. Hence, an increasing number of roentgen-cephalometric analyses is now based on computerized data processing. The objective of this paper was to cast light on various aspects of computerized latero-lateral teleroentgenographic analysis by presenting recent literature data pertaining to this subject. The following conclusions have been reached: despite the fact that the number of data processed is very large, the time of processing is ten times shorter compared to conventional data processing; most analytical errors refer to the location of roentgen-cephalometric points; elaboration of orthodontic treatment on the basis of computerized growth prognosis is not recommended; despite its systemic limitations, there are numerous arguments in favor of the routine use of computerized roentgeno-cephalometric analysis.

Cephalometry↗
PubMed1991

Radiographic and electronic diagnostic systems.

Radiography forms the basis for determining the length of tooth in endodontic therapy. Radiographs can be manipulated by digital image processing, which can improve their diagnostic quality as well as enable the images to be stored electronically. Electronic apex locators, when used in conjunction with radiographs and electronic imaging systems, become useful adjuncts in endodontic treatment. They provide the clinician with the ability to accurately determine the length of tooth, thus making apex locators an important component in endodontic therapy.

Dental Pulp Cavity↗
PubMed1992

An introduction to model-based imaging.

The purpose of this paper is to clarify the distinction between the recognition of form, i.e. pattern recognition, and the interpretation of visual scenes, i.e. image understanding. Pattern recognition is part of image understanding, but the latter also includes cognitive tasks such as learning and inference. The key to developing image-understanding systems is to concentrate on the representation and use of models. This paper is a brief outline of the components of a model-based image-understanding system. First, the notions of iconic, categorical and symbolic knowledge are described. Although they appear to be disparate, the common notion is that the image understanding is based on recognizing concepts and not recognizing form. Next, the notion of a concept is defined, followed by representation techniques and control strategies for using concepts. Last, an example is given of an image-understanding system that learns to recognize concepts such as radiographic projections of teeth in panoramic radiographs.

Expert Systems↗
PubMedDate not supplied

Combining evidence from multiple imaging modalities: a feature-analysis method.

This study was designed to develop methods to improve radiologists' ability to detect and diagnose breast cancer. We evaluated the ability of a feature-analysis method to help radiologists merge judgements constructively from two rather disparate breast imaging tests. To accomplish these goals, we developed a list of perceptual features and quantitated the importance of each in the diagnosis of patients having both diaphanography (Test 1) and mammography (Test 2). Then, two decision aids were developed: One was a checklist of the critical diagnostic visual features from both tests that also assisted readers in rating these features numerically. The second was a computer-based classifier that assisted readers in merging the assessments of the two tests into one overall diagnostic probability. The value of these aids was assessed by comparing radiologists' accuracy in reading a set of proven cases in their standard fashion with their accuracy when reading in an enhanced mode, utilizing the checklist and computer classifier. When Test 1 was read adjunctively with Test 2, use of the decision aids led to a significant improvement in accuracy (p = .013) over the unenhanced, combined readings. For Test 1 alone, the aids led to a significant improvement over its low level of unenhanced reading (p = .046). For Test 2 alone, the enhancements provided little gain in accuracy over an already high level of performance on the full case set (p = .081), although significant gains were realized on the most difficult ones. We conclude that methods to aid standardization and merging of feature-based judgements can improve radiologists performance on complex diagnostic tasks.

Breast Neoplasms↗
PubMed1992

Image preprocessing for a picture archiving and communication system.

OBJECTIVES AND RATIONALE: In a picture archiving and communication system (PACS), images are acquired from multiple modalities and displayed on an electronic workstation. Each modality has different image characteristics. This variability must be addressed before the image is displayed. METHODS: The authors developed methods to automatically process magnetic resonance (MR), computed tomographic (CT), and computed radiography (CR) images before display and subjectively evaluated their effectiveness. RESULTS: Unwanted background successfully was automatically removed from 89.5% of 615 CR images. Of 803 chest, abdomen, and hand images 93% were automatically rotated to the correct orientation. CONCLUSIONS: Automated preprocessing of PACS images can be performed successfully, improving speed and convenience for the radiologist interpreting images at an electronic workstation.

Image Processing, Computer-Assisted↗
PubMed1992

Bending and fracture of the femoral component in cemented total hip replacement.

A computer method was used to make 41 measurements on the geometry of insertion of the femoral component in 200 Charnley total hip replacements. Surgery had been performed at least 12 years before, giving results which were classified as: success (90); fracture (56); or loose (54), according to rigid selection criteria. Fracture was associated with heavier patients in which there was poor proximal fixation of the femoral component but adequate distal fixation. Stems with a medial disposition proximally were more common in the fracture group than in the successful or loose groups. Sequential measurements of bending and subsequent fracture were made on the follow-up radiographs of 24 of the 200 cases (6 fracture and 18 successful). These measurements allowed bending to be detected at an earlier stage than by simple inspection of the radiographs.

Aged↗
PubMedDate not supplied

Retrospective fusion of radiographic and MR data for localization of subdural electrodes.

Prior to epilepsy surgery, subdural electrodes are often implanted and monitored for a few days to identify the focus of abnormal electrical activity. During the implantation and subsequent brain resection, there may be uncertainty about the exact location of the electrodes with respect to features of brain anatomy such as specific gyral convolutions or lesions. In experiments with a phantom and patients, implanted electrodes were imaged with multiplanar skull radiographs (or CT scans). After retrospective registration with preimplantation MR data, the electrodes were mapped from these studies onto an MR-derived three-dimensional brain model. The resulting multimodality displays showed the relationship of the electrodes to brain anatomy. In one patient the position of each electrode with respect to a metabolic lesion was also displayed by mapping preimplantation PET data onto the same brain model. This new display of electrode positions may strengthen the interpretation of subdural electrical recordings and thereby reduce uncertainty in planning the resection of epileptic tissue.

Adult↗
PubMedDate not supplied

Image processing in digital chest radiography: effect on diagnostic efficacy.

The usefulness of digital image processing of chest radiographs was evaluated in a clinical study. In 54 patients, chest radiographs in the posteroanterior projection were obtained by both 14 inch digital image intensifier equipment and the conventional screen-film technique. The digital radiographs (512 x 512 image format) viewed on a 625 line monitor were processed in three different ways: (1) standard display; (2) digital edge enhancement for the standard display; and (3) inverse intensity display. The radiographs were interpreted independently by three radiologists. The diagnoses were confirmed by CT, follow-up radiographs and clinical records. Chest abnormalities of the films analyzed included 21 primary lung tumors, 44 pulmonary nodules, 16 cases with mediastinal disease and 17 cases with pneumonia/atelectasis. Interstitial lung disease, pleural plaques, and pulmonary emphysema were found in 30, 18 and 19 cases, respectively. The sensitivity of conventional radiography when averaged overall findings was better than that of the digital techniques (P less than 0.001). The differences in diagnostic accuracy measured by sensitivity and specificity between the three digital display modes were small. Standard image display showed better sensitivity for pulmonary nodules (0.74 vs 0.66; P less than 0.05) but poorer specificity for pulmonary emphysema (0.85 vs. 0.93; P less than 0.05) compared with inverse intensity display. We conclude that when using 512 x 512 image format, the routine use of digital edge enhancement and tone reversal at digital chest radiographs is not warranted.

Adolescent↗
PubMed1991

Computer-aided interpretation and quantification of angular periodontal bone defects on dental radiographs.

Capabilities of human observers to detect and describe small bone defects objectively are limited. Digital image processing can provide a useful contribution to the diagnostic process. This paper describes the evaluation of a computer-aided procedure for the interpretation and quantification of angular periodontal bone defects on dental radiographs. The computer-aided procedure was able to rank series of artificial periodontal bone lesions as accurate as experienced clinicians. Comparison of data from clinical inspection of lesions during surgery and quantitative results of the digitized procedure shows that the latter produced reliable information on the lesions size. Reproducibility is satisfactory. It was concluded that computer-aided detection and description of periodontal bone defects decreases the interobserver variability in general and the time-dependent variability in repeated assessments of a single observer.

Alveolar Bone Loss↗