Pulmonary digital subtraction angiography

Pulmonary angiography using intravenous rather than intra-arterial injections and digital subtraction technique provides an alternative to dependence on clinical impression, lung scans, and the more invasive transcardiac selective pulmonary angiogram for the diagnosis of pulmonary embolism. However, successful studies of the pulmonary circulation using IV-DSA require careful preselection of patients and meticulous attention to technical detail, as well as a state-of-the-art digital imaging system.     

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.     

Intra-arterial digital subtraction angiography

DSA is an imaging technique that should be integrated into a state-of-the-art angiographic system for proper application and utilization. This results in improvements in both efficiency and diagnostic accuracy. However, from the physician's viewpoint, the proper use of a DSA imaging facility mandates not only an understanding of angiographic principles as applied with conventional film-screen systems but also an in-depth understanding of the factors that affect DSA performance. In particular, factors affecting spatial resolution and contrast sensitivity are crucial. This knowledge has to be applied interactively and "on-line" to achieve optimal IA-DSA image quality.     

Intracranial intravenous digital subtraction angiography

Summary Intravenous digital subtraction angiography (iDSA) promises to significantly alter the use of conventional cerebral angiography in the workup of neurological patients. Understanding its diagnostic potential and its limitations are important in incorporating this new examination into the diagnostic thought process of neuroradiologic tests. Different image processing techniques such as integration of mask and contrast images promise to improve image quality for neuroradiologic application. At present, iDSA is suitable for the diagnosis and follow-up of vascular lesions (atherosclerosis, aneurysms, arteriovenous malformations, venous sinus occlusion), and tumor (meningioma). Although limited, the spatial resolution of iDSA studies is capable of demonstrating diffuse vascular disease such as arteritis and vasospasm after subarachnoid hemorrhage. In some patients in conjunction with the CT scan, iDSA may prove sufficient as the primary and only diagnostic angiographic test necessary, supplanting conventional angiography.Supported by NJH Contract 1 RO1HL 25905-O1A1     

Pulmonary digital subtraction angiography: a screening tool for vascular lung lesions

Pulmonary digital subtraction angiography offers a further method of distinguishing vascular from avascular lesions in the lung. The computerised (digitised) recording allows versatility of data manipulation and post-processing and is of particular value in identifying a vascular component in complex lung masses. In the five cases described, digital subtraction angiography provided useful information; in three, it was the definitive diagnostic procedure.     

Cardiovascular applications of digital subtraction angiography

Continuing interest exists in the cardiovascular applications for digital subtraction angiography. The principal intravenous application is in the evaluation of left ventricular function and the quantitative parameters presently available for digital methods. Intraarterial applications include the ability to screen multiple vascular systems, including the coronary circulation and the carotid or peripheral vascular structures. Quantitative functions available are stenosis sizing, phase and amplitude analysis, and, finally, "road mapping" during cardiovascular interventional procedures. Major expansion of storage capacity, cine pulsing, and immediate access of online data represent a few of the major limitations of the procedure.     

Upper-extremity venography using digital subtraction angiography

Venography to evaluate the patency of upper-extremity veins was performed with digital subtraction angiography (DSA) and conventional angiography. Venous thrombosis was easily diagnosed, and the innominate veins and superior vena cava were more easily visualized using DSA. Iodine concentration for DSA was one-third that of conventional venography, and the examination time was reduced by 50% using DSA. Patient comfort and acceptance were greater with DSA. DSA is a superior technique for upper-extremity vein evaluation in cooperative patients.     

Limitations of intravenous digital subtraction angiography

Eighteen digital subtraction angiography (DSA) examinations were retrospectively evaluated for factors that led to their erroneous interpretation. Overlapping vessels obscured pathologic conditions in five cases. In four cases the lesions were not adequately profiled by the DSA projections. Eight lesions were rendered inconspicuous by misregistration artifacts attributable to motion, either from swallowing or from pulsation of vessel walls. One diagnostic error was caused by poor opacification from a degraded contrast bolus secondary to low cardiac output.     

Tomosynthesis applied to digital subtraction angiography

This extension of our previous work on tomographic digital subtraction angiography (DSA) describes the theory of tomosynthetic DSA image reconstruction techniques. In addition to developing the resolution limits resulting from x-ray exposure length and image intensifier field curvature, we describe one method of image formation and show tomosynthetic DSA images of animal and human anatomy. Methods for improving the present technique are discussed.