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The accuracy of digital subtraction angiography for the quantification of atherosclerosis.

Digital subtraction angiography (DSA) allows the degree of arterial patency or stenosis to be rapidly quantified. We have assessed the accuracy with which a single-plane DSA system is able to quantify area patency by densitometric and geometric methods. Arterial phantoms were designed to test for systematic error; intra-arterial DSA images of critical lesions of the carotid bifurcation and the lower abdominal and peripheral vessels were used to determine intra- and interobserver reproducibility. The densitometric method, which was more accurate than the geometric method, had a mean systematic error of up to 4% and a mean intra-observer variability of about 15% (coefficient of variation). We have identified the principal sources of inaccuracy and ways in which it may be reduced.

Arteriosclerosis↗

Digital subtraction angiography in children.

Preliminary results with digital subtraction angiography in infants and children have shown this to be an excellent screening procedure and often diagnostic. The examination can be performed satisfactorily on outpatients. Sixty patients have undergone this examination for evaluation of suspected abnormalities of the aortic arch and its branches, intracranial arteries, pulmonary arteries, abdominal aorta and its branches, and peripheral vessels. Adequate sedation is mandatory to prevent motion artifacts. While the literature reports increasing use of central venous catheters for delivery of contrast material, the use of short catheters placed in an antecubital vein is satisfactory for the pediatric patient. Techniques of the procedures are described along with seven appropriate case examples.

Angiography↗

Intravenous digital subtraction angiography of arteriosclerotic vertebrobasilar disease.

Intravenous digital subtraction angiography (DSA) was performed in 111 patients with vertebrobasilar ischemia. Ninety percent of the vertebral images were of diagnostic quality; 23% of the basilar images were good quality and 53% fair quality; and 58% of the posterior cerebral images were poor. Compared with selective film arteriography in 23 patients, DSA tended to underestimate the degree of atheromatous disease. Segments of the basilar artery were often poorly seen, which could result in false-negative errors. DSA can provide a general assessment of atheromatous disease of the brachiocephalic vessels, including the vertebral and carotid arteries, and in many cases can exclude occlusion or critical stenosis of the vertebrobasilar system. However, it does not adequately image the posterior cerebral or cerebellar artery.

Basilar Artery↗

[Resolution capacity in intra-arterial digital subtraction angiography of the A. carotis].

Intraarterial digital subtraction angiography of the intracranial vascular system is increasingly one of the more important advances in neuroradiology. The paramount disadvantage is less spatial resolution. Based on experimental and theoretical studies recommendations are given to reach a optimum of spatial resolution: Selective intraarterial application of undiluted contrast medium (300 mgJ/ml); volume: 3 ml in a. carotis comm.; flow: 5 ml/sec.

Carotid Artery, Internal↗

Digital subtraction angiography system evaluation with phantoms.

Advances in digital subtraction angiography imaging demonstrate the need for critical evaluation of the performance of digital subtraction equipment. The design of a phantom set for noninvasive assessment of the imaging quality of digital subtraction equipment is described; components include a remotely controlled transport system and individual patterns to evaluate the contrast and detail properties of the image intensifier, low-contrast sensitivity and resolution of the system, geometric distortion of image, linearity, mechanical and electronic stability of equipment, and effects of bone and bowel gas on iodine perception. The performance of an add-on digital radiographic system is presented, along with radiation exposure levels at the image intensifier for a range of radiographic techniques.

Angiography↗

Digital subtraction angiography in the diagnosis of retinal vascular disease.

Digital subtraction angiography is a safe, inexpensive method of investigating systemic vascular disease in patients for whom conventional carotid angiography is too risky. We used this technique in five patients with a variety of retinal vascular conditions--a 55-year-old woman with occlusion of the right internal carotid artery, a 63-year-old man with bilateral occlusion of the internal carotid arteries, a 72-year-old man with occlusion of the stem of the left subclavian artery and an irregularity of the proximal portion of the innominate artery, a 77-year-old man with optic nerve head neovascularization and stenosis of the left internal and external and right internal carotid arteries, and a 74-year-old man with recurrent stenosis of the left internal carotid artery. In all five cases, digital subtraction angiography was helpful in determining the diagnosis and course of treatment.

Aged↗

[Intravenous digital subtraction angiography (DSA). Experience in 600 cases].

Intravenous digital subtraction angiography has been employed to examine arteries in 600 patients. Conventional angiography was used in 41 cases where insufficient DSA was made, or as definitive preoperative investigation. In 88% the digital subtraction angiogram is diagnostic, and conventional angiography then shows little more additional information.

Angiography↗

Update and trends in venous (VDSA) and arterial (ADSA) digital subtraction angiography in neuroradiology.

After presentation of the principles and technology of digital subtraction angiography the results of 649 investigations with the peripheral venous method are presented and first experiences are discussed critically. In conclusion the method of venous digital subtraction angiography can be stated to be useful for adequate diagnosis of the extracranial brain vessels. Diagnostic statements about the intracranial vessels by venous injection are limited, and therefore a combined investigation including normal angiography remains necessary. In the near future neuroradiological investigations cannot abandon selective arterial techniques. One may expect however that normal angiographic investigations will subsequently be replaced by digital subtraction angiography with arterial injection of contrast medium.

Angiography↗

Digital subtraction angiography: present and future uses in cardiovascular diagnosis.

Digital subtraction angiography (DSA) has been proved to be an effective means of visualizing the cardiovascular system following intravenous injection of contrast material. Excellent quality images have been obtained of the left ventricle, the thoracic aorta and its major branches, the carotid arteries, the abdominal aorta and its major branches, lower extremity vessels, and intracerebral vessels. Avoiding the risks and discomforts of direct arterial puncture and the need for hospitalization, DSA is safer and more economical than standard arteriography. It is, therefore, useful both as a screening tool and, in many patients, as a diagnostic tool for the evaluation of vascular disease. Left ventricular studies provide excellent qualitative and quantitative evaluation of left ventricular function. Arterial injections of contrast have provided excellent quality images of the vascular tree with low volume dilute contrast material. Lower extremity vessels not visualized by standard arteriography have been seen following intra-arterial contrast injections using DSA. Aortic root injections have been used to demonstrate coronary arteries and coronary artery bypass grafts. Although intravenous injections of contrast have shown coronary artery bypass graft patency with reasonable success, they have not proved useful at this point in defining the exact anatomy. Other video techniques following arterial injections of contrast have been used to calculate vessel flows. Although coronary artery images in animal studies following intravenous contrast injection are improving, they are still not of diagnostic quality. Digital subtraction angiography, therefore, has proved itself a useful adjunct to standard arteriographic techniques. Its future potential has not yet been defined.

Angiography↗

[A digital subtraction angiography system based on LUT algorithms].

Look-up table (LUT) algorithms have been widely used in digital signal processing, but the article on the application of LUT algorithms in digital subtraction angiography was rarely reported. In this article, the effect of different LUT algorithms on digital subtraction angiography images is introduced. The result reveals that different LUT algorithms can bring about different effects of image. Based on analysis and comparison, we deem it possible to acquire improved images of DSA by use of some LUT algorithms with image processing.

Algorithms↗

Intra-arterial digital subtraction angiography through the ear artery for experimental aneurysm imaging.

Digital subtraction angiography through the central artery of the ear was performed to show elastase-induced aneurysms in 34 rabbits. Twenty-eight (82%) aneurysms in which common origins of the bilateral common carotid artery (CCA) were found were well shown. All 6 other aneurysms not well shown had separate origins of the CCAs from the aortic arch (P < .001). This method can be used for angiographic follow-up when there is a common origin of the CCAs.

Angiography, Digital Subtraction↗

Contrast-enhanced 3D MR angiography of the carotid artery: comparison with conventional digital subtraction angiography.

BACKGROUND AND PURPOSE: Since 1996, several preliminary studies have shown the usefulness of contrast material-enhanced MR angiography for imaging supraaortic vessels. The aim of this study was to compare the accuracy of contrast-enhanced 3D MR angiography with that of digital subtraction angiography (DSA) in the evaluation of carotid artery stenosis. METHODS: A blinded comparison of first-pass contrast-enhanced MR angiography with conventional DSA was performed in 120 patients (240 arteries). MR angiography was performed with a 1.5-T magnet with gradient overdrive equipment, by using a coronal radiofrequency-spoiled 3D fast low-angle-shot sequence after the intravenous injection of gadodiamide. The guidelines of the North American Symptomatic Carotid Endarterectomy Trial for measuring stenosis of the internal carotid artery were applied on maximum intensity projection (MIP) images and conventional catheter angiograms. RESULTS: Grading of stenoses on MR angiograms agreed with grading of stenoses on DSA images in 89% of arteries. In the severe stenosis group (70-99%), agreement was 93%. All internal carotid occlusions (n = 28) and seven of nine pseudo-occlusions were accurately detected with contrast-enhanced MR angiography. The correlation between MR angiography and DSA for determination of minimal, moderate, and severe stenoses and occlusion was statistically significant (r = 0.91, P<.001). CONCLUSIONS: This investigation with a large number of patients confirms that contrast-enhanced MR angiography could become a diagnostic alternative to DSA in the treatment of patients with carotid artery disease.

Adolescent↗

Carotid bifurcation stenosis: a comparative study between MR angiography and duplex scanning with respect to digital subtraction angiography.

PURPOSE: This study compared sensitivity, specificity and diagnostic accuracy of Echoduplex and Magnetic Resonance Angiography (MRA) in the evaluation of carotid bifurcation stenosis. MATERIAL AND METHODS: Twenty-five patients with clinical signs suggestive for cerebrovascular insufficiency (CVI) were studied with Duplex scan, MRA and Digital Subtraction angiography (DSA). Gold standard was the angiographic examination. RESULTS: on equal value of sensitivity (80.5%), MRA showed 96% specificity versus 81% of Duplex scan, 89.4% diagnostic accuracy versus 80.9% for Duplex scan. As for stenosis over 31%, the value of sensitivity did not change i.e., 80.5%; MRA showed 100% specificity versus 97.1% for Duplex, 91.2% diagnostic accuracy versus 89.1% respectively. These values compared by the test for categorial analysis and correspondence analysis (p < 0.05) did not indicate any statistically significant difference. DISCUSSION: on the basis of our experience and as shown by current literature [2, 12] we can state that both MR-angiography and Duplex scan fail in quantifying correctly carotid stenosis with consequent over- and underestimation [3, 4]. However, they can be considered effective diagnostic procedures in a screening program [12, 16]; they are accurate, safe and accepted by the population. CONCLUSIONS: on the basis of the cost in planning the screening of a population at risk for CVI, Duplex scanning is still to be considered the elective procedure.

Adult↗

[The value of intravenous digital subtraction angiography in Leriche's syndrome].

The value of intravenous digital subtraction angiography was examined in 20 patients with Leriche's syndrome. The method is highly accurate for localising the level of the aortic occlusion (100%), the demonstration of distal patency (95%) and the collateral circulation (90%). An important advantage of this method compared with transaxillary, transbrachial or translumbar aortography is its low invasiveness.

Adult↗

Peripheral vascular disease: prospective study of intraarterial digital subtraction angiography using a 9-inch intensifier.

A prospective randomized study was undertaken to evaluate the role of intraarterial digital subtraction angiography (IADSA) in the study of peripheral vascular disease. Patients underwent either conventional film-based angiography alone, digital subtraction angiography (DSA) alone, or a combined study. With a 9-inch image intensifier, DSA alone resulted in cost savings of film and contrast material but required a significantly longer examination period than the other groups and an increased iodine dose per examination. When the images were analyzed by a radiologist and a vascular surgeon, the DSA studies provided less detail in the aortoiliac region than the other techniques but had advantages in demonstrating the runoff vessels. IADSA examination should not replace conventional arteriography in patients with peripheral vascular disease but has a useful complementary role.

Aged↗

Low infusion rate digital subtraction angiography to predict regional perfusion in hepatic arterial chemotherapy.

Digital subtraction angiography (DSA) with a low injection rate of contrast (0.5 ml/sec) was studied as a means of predicting the regional perfusion of percutaneously placed catheters for hepatic arterial chemotherapy. In 64 hepatic artery catheter placements, conventional injection rate angiography (3-5 ml/sec) and low infusion rate DSA exams were compared to conventional radionuclide perfusion studies performed with Tc-99m-MAA. In 58 of 64 cases (90.6%) the conventional arteriogram correctly predicted the extent of hepatic perfusion, whereas in 63 of 64 cases (98%), the low flow DSA exam correctly predicted hepatic perfusion. The conventional arteriogram correctly predicted the extent of extrahepatic perfusion in 32 cases (50%), with a sensitivity of 100%, but a specificity of only 39.6%. The DSA exam was correct in defining the presence or absence of extrahepatic perfusion in 57 of 64 cases for a sensitivity of 82% and a specificity of 91%. Despite the quantitative difference between the low infusion rate DSA study and the chemotherapy infusion (10 ml/hr), it is a useful tool to assist in the correct positioning of temporary catheters for hepatic arterial chemotherapy.

Angiography, Digital Subtraction↗