SEARCH · PubMed Health
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.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
ECG-triggered DSA of the pulmonary arteries enables far-reaching avoidance of image artifacts which are due to pulsation. However, trigger delay and image duration must be adapted subtly to the individual heart rate. Whereas adaptation of trigger delay can be effected via programming of the new generation of equipment, further improvements will be necessary to achieve an adequate image life or duration of the pulsed irradiation. Experience collected so far has shown that ECG-DSA of the pulmonary arteries yields results that are as valid as those obtained via perfusion scintigraphy, so that this method can be used in initial examination to establish the diagnosis of pulmonary embolism. The use of ECG-DSA is not indicated in absolute cardiac arrhythmia.
This paper is a review of digital radiography, the application of digital electronic technology to medical X-ray imaging. At some stage in the formation of an image the detected X-ray fluence is converted into a digital format for processing and display. In many X-ray procedures digital methods offer considerable advantages over previously used techniques in speed, precision, flexibility, sophistication of processing, or other characteristics. These in turn can lead to reductions in degree of invasiveness, X-ray exposure, or contrast material dose or certain other advantages such as reduced time per X-ray procedure. The major digital X-ray imaging techniques are discussed, ranging from contrast enhancement to image subtraction schemes to more recently developed methods such as temporal filtering of image sequences at realtime video rates. Digital imaging systems are categorized according to detector geometry, and the relative merits of each are discussed. Examples of clinical applications are given.
The term "Digital Radiography" covers all x-ray techniques which produce a projected image with the help of digital imaging techniques, which are very similar to a conventional x-ray film image. The advantage of "Digital Radiography" is the possibility of digital image processing, like the subtraction technique, the selective material filtering technique and the quantitative image plotting technique. With the equipments now in use, the digital projected image is produced by the line or on an even level. One example of the in-line projected image is the so-called "topogram", produced via computed tomography equipment. With the help of an x-ray video chain, it is possible to produce digital images on an even level. This technique is used, for example, for "digital video subtraction angiography" (DVSA). Today, digital radiography is clinically used only in the "DVSA" and the "topogram" systems. A survey of the clinical use and the improved future possibilities of digital radiography is given, and the special features of the method are discussed.
Explore the source record for details and available documents.
Digital radiography is a rapidly developing new approach to cardiovascular imaging that converts radiographic and fluoroscopic video images into digital format for subsequent image enhancement, analysis, and storage. Cardiac applications proven clinically useful to date include intravenous and reduced-contrast load direct left ventriculography, aortic root bypass graft visualization, and selective coronary arteriography, which allows quantification of arterial stenoses and flow reserve. Myocardial functional reserve can be assessed using exercise or atrial pacing. Advantages over standard radiography include reduced radiation and contrast medium burden, visualization of very low contrast medium concentrations, and an image format that can be directly analyzed by quantitative techniques. As these cardiac applications are developed and improved archiving is implemented, it is likely that the digital approach will replace standard cardiac angiography.
An automated differentiation of the P loop from other VCG loops, its 20-fold magnification, visualization, and computation of its major spatial and projection parameters have been made possible, giving precise information on its configuration, duration, the direction of recording, as well as relative positions and directions of its instantaneous vectors. Digital computerization of the traces has produced different vector and scale characteristics of the spatial Pxyz loop.
Explore the source record for details and available documents.
We have been using digital tomography (TOMOTRON) clinically for eight months. Its advantages include savings in both time and dose, good image quality through increased contrast, and improved magnification and image postprocessing compared with conventional tomography. However, lower image resolution and small image sections are the disadvantages of digital tomography. Weighing these advantages and disadvantages by our experience, the diagnostic accuracy of digital tomography is higher than conventional tomography, particularly in skeletal studies.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.