Pulmonary digital subtraction angiography

Intravenous digital subtraction pulmonary angiography was performed in 220 patients. Of these, 206 had suspected pulmonary embolism. Our intravenous studies yielded images of diagnostic quality in 98% of cases. Compared to conventional pulmonary angiography, intravenous digital subtraction angiography (IV DSA) is safer, faster, and easier to perform. This technique is an acceptable substitute for routine pulmonary angiography in all patients with pulmonary embolism. Intravenous DSA is currently the procedure of choice for the evaluation of patients with suspected pulmonary embolism.     

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.     

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.     

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.     

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     

Stereoscopic digital subtraction angiography in neuroradiologic assessment

Digital subtraction angiography (DSA) with stereoscopic imaging was performed in 40 patients for evaluation of a variety of cerebrospinal disorders. It was facilitated by a C-arm mounted x-ray tube and imaging chain with 7 degrees angulation between image pairs. Stereoscopic digital imaging proved particularly useful in the preoperative assessment of aneurysms, arteriovenous malformations, and primary and metastatic tumors. The technique was also found to be useful as a real-time adjunct to therapeutic radiographic procedures, as an aid in stereotaxic procedures, and in follow-up of postsurgical patients. Although the intravenous route was occasionally used, especially in postoperative follow-up of aneurysms, the procedure was most often carried out via an intraarterial approach. Stereoscopy was useful in supplying depth information regarding the relations between lesions and surrounding normal and abnormal vasculature. This technique combines the demonstrated advantages of intraarterial DSA with the unique advantage of stereoscopic imaging to demonstrate three-dimensional detail, thus contributing significantly to diagnostic confidence. Disadvantages are discussed. Further refinements in the equipment are expected: generation of stereo images with one injection, thus increasing procedure efficiency and patient safety; a video stereoscopic viewing unit; and the ability to obtain precise measurements via computer of depth, position, distance between, and true size of objects.     

Intravenous digital subtraction angiography in non-specific aorto-arteritis

We have studied 40 patients with non-specific aorto-arteritis (Takayasu's disease) using intravenous digital subtraction angiography (DSA). The aorta, its major branches and (in 18 patients) pulmonary arteries were evaluated to determine the degree and extent of involvement. No complications related to the procedure were encountered. Good quality diagnostic images were obtained in 39 out of 43 instances. The unsuccessful examinations were in patients with congestive cardiac failure, and in one patient who would not co-operate. Aortic wall thickness and mild involvement of the descending aorta in the region of the diaphragm could not be assessed. Intravenous DSA is acceptable for the diagnosis and follow-up of aorto-arteritis in suitable patients.     

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.     

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.     

Intravenous digital subtraction angiography in intracranial aneurysms

Intravenous digital subtraction angiography was undertaken in 121 patients with known intracranial aneurysms. Its role in the management of these patients and its diagnostic accuracy have been assessed.     

Intraarterial digital subtraction angiography in diagnostic arteriography

Intraarterial digital subtraction angiography (DSA) was performed in 133 diagnostic arteriographic procedures during a 10-month period. The increased contrast resolution of DSA permitted the use of a dilute (15%) contrast material. A significant reduction in contrast material dose compared with conventional film-screen arteriography and intravenous DSA was thus achieved. This was especially advantageous in patients with diminished renal function. The dilute contrast material also resulted in less patient discomfort. Subtracted images were available immediately on cathode ray tube display, resulting in faster procedures, and a considerable saving in film cost compared with conventional arteriography. It is concluded that intraarterial DSA is a useful technique that may replace conventional film-screen arteriography in many applications.