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At least 19 recordsLinked to original sources
PubMed1986

Digital subtraction angiography.

Digital subtraction angiography is a new imaging technique that uses a computer to subtract background distractions and to enhance contrast and density. The intravenous administration of contrast material permits safe outpatient screening for arterial disease. The exact role of intravenous digital subtraction angiography in cerebrovascular disease is still in evolution and remains the subject of debate. The value of intravenous digital subtraction angiography in screening for renovascular hypertension is less controversial, but selection of patients remains a subject for further study. Intra-arterial digital subtraction angiography has become a standard imaging technique that offers both the inherent safety produced by reduction of the volume of contrast material and the added safety afforded by reduction of both the size of the catheter and the time required to perform complex arterial interventional procedures. With the evolution of more sophisticated computed technology and radiographic equipment, the impact of both intravenous and arterial digital subtraction angiography will become even more dramatic.

Angiography↗
PubMed1983

Screening for transplant renal artery stenosis in hypertensive recipients using digital subtraction angiography.

Digital subtraction angiography was used in 10 renal allograft recipients with sustained hypertension after transplantation to detect transplant renal artery stenosis. Recipients with end-to-end vascular anastomoses were visualized adequately in the anteroposterior projection. Two cases of transplant renal artery stenosis were identified by digital subtraction angiography and then verified by catheter angiography. Patients with end-to-side vascular anastomoses may require additional oblique projections. Digital subtraction angiography is a safe, noninvasive and cost-effective screening procedure to diagnose transplant renal artery stenosis in most recipients. Catheter angiography can be applied more selectively to those recipients with stenosis observed by digital subtraction angiography or when more detailed imaging is required.

Adolescent↗
PubMed1988

Acute pulmonary embolism: diagnostic value of digital subtraction angiography.

Digital subtraction angiography (DSA) performed via a peripheral vein was compared prospectively with selective conventional pulmonary angiography (CPA) in 54 patients suspected of having pulmonary embolism (PE). All patients also underwent ascending venography. In contrast to the conventional pulmonary angiograms, all of which were considered satisfactory, 13 of 54 digital subtraction angiograms (24%) were technically unsatisfactory. The interpretable digital subtraction angiograms had 81% sensitivity and 64% specificity. With DSA, one cannot exclude the diagnosis of PE on the basis of normal angiograms (27% false-positive results) as one can with perfusion scanning. On the other hand, DSA showed good sensitivity (94%) in medium to major PE. Therefore it may be the technique of choice in the screening of life-threatening PE for which curative emergency treatment with thrombolytic agents or embolectomy is often necessary.

Acute Disease↗
PubMed1986

Parametric imaging using digital subtraction angiography.

Digital subtraction angiography following an injection of iodinated contrast material can regularly produce good quality images. In addition to the conventional anatomical information, the timed sequence of digital images also contains useful temporal information which hitherto has been largely ignored. A simple method of image processing is described which utilises this timing information and presents it as a colour-coded set of functional images. Three parameters MAX, T-MAX and T-1/2 MAX are extracted from time-density curves, analogous to the time-activity curves of Nuclear Medicine, on a pixel-by-pixel basis. These parameters are used as a measure of overall organ perfusion, blood transit time between different vascular compartments, and as an indication of the initial delivery of contrast material to an organ. They have found use in the analysis of myocardial perfusion, before and after pharmacological intervention, and in the examination of the cerebral and renal circulations. The potential advantages of this technique derive from its superior spatial, temporal and contrast resolution.

Angiography↗
PubMedDate not supplied

A quantitative in vivo comparison of six contrast agents by digital subtraction angiography.

Digital subtraction angiography (DSA) technology can now visualize many significant arterial structures from intravenous injections of contrast media. Image quality of these DSA studies is related to contrast agent enhancement. This study compares contrast agents of differing iodine concentration, viscosity, and osmolarity. A technique is described that utilizes a scanned projection digital radiographic system to compare quantitatively degrees of intra-arterial opacification after the administration of six intravenous contrast agents: iothalamate (at four different concentrations and in combinations with two different cations), diatrizoate, and ioxaglate. The quantitative arterial enhancement was compared in dogs utilizing an extra-period latin-square multiple change-over clinical trial design. The contrast agents span a range of organically bound iodine from 282 mg I/ml. When rate and volume of contrast agent injected are held constant, intra-arterial opacification is directly a function of the iodine concentration (mg I/ml) of the agent injected, while osmolarity and viscosity have no effect on opacification. These studies support the use of agents with high iodine concentration for maximum vascular visualization.

Angiography↗
PubMed1989

[Limits of the diagnostic capability of pulmonary digital subtraction angiography].

Digital subtraction pulmonary angiography was performed in 70 patients suspected of having pulmonary emboli. In 35 patients this diagnosis proved to be correct. The technical quality of all ECG-gated studies was scored and was found to be satisfactory in 31 patients (44%), moderate in 23 (33%) and unsatisfactory in 16 patients (23%). This was mainly due to the lack of patient cooperation. In patients with direct injection into the pulmonary artery (27%) the motion artifacts were less disturbing. We therefore suggest that even when using ECG-gated acquisitions, the injection should be performed into the pulmonary artery to overcome technical problems in the diagnosis of pulmonary embolism.

Adult↗
PubMed1987

Quantitation of aortic regurgitation by computer analysis of digital subtraction angiography.

Digital subtraction angiography provides the potential to determine aortic regurgitant fraction by computer analysis of time-intensity curves generated from regions of interest positioned over the aorta and left ventricle after aortography. To validate this ability, we studied six dogs instrumented with an electromagnetic flow probe on the ascending aorta. Aortic regurgitation of varying severity was produced by a basket catheter introduced through the right carotid artery. Aortograms were performed using continuous fluoroscopy at 30 frames/s and stored in digital format in a 256 x 256 pixel matrix. An image-processing computer was utilized to plot summated pixel intensity versus time for both the aortic and the left ventricular regions of interest. Regurgitant fraction was calculated from the time-intensity curves using an algorithm analogous to that employed by dye-dilution methods. Regurgitant fraction determined from digital angiography was compared with that obtained by electromagnetic flow and was found to correlate well (r = 0.94, SEE = 7.4%) over a wide range of values. Thus, these data indicate that aortic regurgitant fraction can be accurately determined from computer analysis of digitally acquired aortograms in an animal model of acute aortic regurgitation.

Animals↗
PubMed1983

Renal digital subtraction angiography.

Digital subtraction angiography (DSA), a new computer-assisted radiographic procedure, has recently been applied to the evaluation of the kidney and in the screening of patients with renal vascular hypertension. The efficacy of the method in the evaluation of the anatomy of proximal renal arteries is in the 80-90% range; however, DSA is less effective in the evaluation of renal mass lesion. In the present state of DSA development, the method has a place in screening for renal artery stenosis (RAS). Further development, particularly improvement in spatial resolution, will be necessary before this procedure can substitute for renal angiography, in the evaluation of renal masses or in some cases of RAS.

Angiography↗
PubMed1985

Localization of carotid cavernous fistula using digital subtraction angiography.

Digital subtraction angiography (DSA), with its rapid imaging rate (30 video frames per second) and immediately available subtraction images, provides excellent vascular detail in localization of the exact site of internal carotid-cavernous fistula. In a patient with two fistulas, we successfully used DSA to determine the sites of fistula and accurately positioned detachable balloons to occlude them.

Adult↗
PubMed1984

Digital subtraction angiography.

Digital subtraction angiography is a new technique that combines fluoroscopic and computer technology to image the vascular system. This "angiogram" is fast and safe, can be performed on outpatients, and requires only intravenously administered contrast medium.

Angiography↗
PubMedDate not supplied

Detection of pulmonary emboli in dogs using digital subtraction angiography.

Digital subtraction angiography (DSA) was performed in six dogs to define the limits of detection of pulmonary emboli. Three angiograms were initially obtained in three normal control animals, two of which were subsequently embolized. A total of ten pulmonary angiograms were then obtained in five dogs that had experimentally produced emboli of Ivalon cubes (2, 3, and 10 mm). The intravenous angiograms were followed by selective arterial angiograms to confirm the presence and location of the emboli. The intravenous angiograms were independently reviewed by two radiologists. The criterion for detection was identification of a vessel cutoff. Perfusion defects were also seen. No intraluminal filling defects were seen. This study indicates that pulmonary emboli greater than 2 mm in diameter may be detected in dogs by DSA.

Angiography↗
PubMed1983

Anatomic and functional imaging of congenital heart disease with digital subtraction angiography.

Digital subtraction angiography (DSA) of the heart was performed in 54 patients for the evaluation of congenital heart disorders. DSA produced high-quality diagnostic images and accurate physiologic shunt data that compared favorably with catheter angiography and nuclear medicine studies. Retrospective analysis of this series of patients indicated that DSA studies contributed sufficient information to shorten significantly or modify cardiac catheterization in 85% (79/93) of the defects that were identified. Interatrial septal defects were particularly well diagnosed, with identification occurring in 10 of 10 cases, whereas intraventricular septal defects were identified in only 6 of 9 patients. Evaluation of postsurgical patients was accurate in 19 of 20 cases.

Adolescent↗
PubMed1987

[Quantitative analysis of the left ventricular volume curve by digital subtraction angiography].

Digital subtraction angiography (DSA) not only permits visualizing the left cardiac and arterial systems after injecting contrast media intravenously, but enables quantitative and functional analyses of the data collected. This report describes our experiences with several videodensitometric analyses for assessing global and regional left ventricular (LV) functions. 1. Analyses of LV volume curves with contrast media In the conventional cineventriculogram, construction of LV volume curves by the area-length method requires tedious efforts, but with DSA, such curves are provided automatically using videodensitometric analyses. The advantages of the DSA method include; 1) DSA has better contrast resolution than radionuclide angiography. 2) The densitometric technique may offer more accurate results than methods based on geometric assumptions, especially when the LV shape is irregular or when it changes during a single cardiac cycle. 2. Analyses of LV volume curves without contrast media Computer analyses of DSA images without contrast media facilitated the noninvasive evaluation of global and regional LV functions. The method is based on the ability to detect small differences in X-ray absorption by the cardiac silhouette during a single cardiac cycle, without any contrast media. We applied this capability to Fourier analysis using radionuclide angiographic computer programs and succeeded in evaluating regional wall motion abnormalities in patients anterior myocardial infarction. In summary, the videodensitometric analysis of the DSA image is a promising new approach for the clinical of LV function, due to its combined capability of automated computerized analysis similar in radionuclide study, and due to higher contrast resolution just like as LV cineangiography.

Absorptiometry, Photon↗
PubMed1985

[Quantitative analysis of myocardial perfusion by digital subtraction angiography].

Digital subtraction angiography (DSA) has been adopted to detect ischemic myocardial areas and to quantitatively evaluate the degrees of myocardial perfusion abnormalities. Subtraction for selective coronary arteriography was performed sequentially between mask and enhanced images in the same cardiac phases by means of ECG signals. We obtained three distinct perfusion phases which we termed the arterial, capillary, and venous phases. Densitometry of the circumferential cardiac wall was performed on these sequential images. The results were compared with 201Tl myocardial scintigrams and cine angiograms. In the arterial phase, the abnormalities of the coronary artery, such as stenosis, obstruction and collaterals were represented. In the capillary phase, contrast materials served as markers of myocardial perfusion and delineated infarctions as areas of low contrast enhancement compared to the normally perfused myocardium. In the venous phase, the infarcted areas were represented as areas with greater relative contrast enhancement than that of the normal myocardium. Circumferential analysis of perfusion could provide more detailed information about myocardial ischemic areas and the degrees of ischemia. Although we used invasive selective coronary arteriography, DSA techniques have numerous merits such as excellent temporal resolution, spatial resolution, and good contrast resolution, over conventional methods. Quantitative DSA methodology which we developed provided not only anatomical information about the main coronary arteries but new information about abnormalities of peripheral myocardial perfusion.

Angiography↗
PubMed1984

Digital subtraction angiography.

Digital subtraction angiography (DSA) is an alternative method for imaging the cerebral vasculature. Intravenous DSA is used primarily for evaluating the common carotid bifurcation. The superior image quality of arterial DSA makes it more suitable for studying intracranial arteriovenous malformations, aneurysms, and tumor circulation.

Brain Neoplasms↗
PubMed1984

Intracranial applications of digital subtraction angiography.

Digital subtraction angiography (DSA) is becoming an important method of studying the intracranial vascular structures. In patients being evaluated for cervicocerebral atherosclerosis, patency of and flow patterns in the major intracranial arteries can be determined. Quantitative as well as qualitative data on relative hemispheric contrast transit times are obtainable. Intracranial aneurysms and vascular malformations can be demonstrated by intravenous DSA, but this technique is unlikely to replace selective intraarterial catheter angiography for the definitive work-up of these conditions. In selected cases, vascular tumors of the intracranial compartment and skull base can be satisfactorily evaluated by intravenous DSA, particularly if precise and intricate anatomic detail is not required. The dural venous sinuses are optimally demonstrated by this modality. Postoperative intravenous DSA is useful for determining the results of surgical treatment of certain conditions, and is suitable for assessing the patency of surgical bypass grafts. The disadvantages of using intravenous DSA for intracranial studies include poorer spatial resolution as compared to conventional angiography, superimposition of vessels, and serious degradation of image quality by patient motion. When greater selectivity and better resolution are required, intraarterial DSA can be performed. Advantages of intraarterial DSA over conventional angiography include the availability of immediate subtraction images, the ability to use dilute concentrations of contrast agent, and lesser film cost. Intraarterial DSA shortens procedure time when therapeutic embolization is performed.

Brain Neoplasms↗
PubMed1996

Comparative study of magnetic resonance angiography, digital subtraction angiography, duplex ultrasound examination with surgical and histological findings of atherosclerotic carotid bifurcation disease.

This study was designed in order to determine the diagnostic accuracy in imaging of the extracranial arteries by using magnetic resonance angiography (MRA), digital subtraction angiography (DSA), B-mode duplex ultrasonic examination (DUE) in comparison with the surgical and histological findings of the specimen removed after endarterectomy. The degree of stenosis of the arterial lumen of the surgical specimen was compared with the imaging findings of MRA, DSA and DUE: a) the degree of agreement of stenosis with histologic findings was found in 89% of cases for MRA, in 93% for DSA and 88% for DUE; b) the correlation of morphology of the plaque showed agreement in 91% of the cases with MRA, in 94% with DSA and 87% with DUE; c) the constitution of the plaque was in agreement with DUE findings in 96% of cases. There is no significant difference between the three methods, as far as the estimation of degree of carotid stenosis and morphology of the atheromatous plaque in the carotid arteries. MRA findings are similar with those of DSA and DUE with a high sensitivity and specificity concerning the constitution of the plaque. The combination of MRA and DUE provides all the necessary information concerning the extracranial segments of the cerebral arteries for the preoperative evaluation of patients with carotid disease.

Angiography, Digital Subtraction↗