Intra-venous digital subtraction angiography: an alternative method to intra-arterial digital subtraction angiography for experimental aneurysm imaging

Conventional intra-arterial digital subtraction angiography (IADSA), which necessitates surgical exposure and ligation of the femoral artery, is an invasive and expensive method of evaluation for experimental elastase-induced aneurysms in rabbits. The purpose of this study was to examine and validate intra-venous digital subtraction angiography (IVDSA) as an alternative to IADSA by comparing their diagnostic accuracies. We performed both IVDSA and IADSA for 24 elastase-induced saccular aneurysms in a rabbit model, 1 month following creation. Aneurysm sizes (neck, width and height) from both the IVDSA and IADSA procedures were evaluated and measured. Comparison of the aneurysm sizes between IVDSA and IADSA were performed with the Wilcoxon paired signed-rank test. All the aneurysms were seen clearly in both the IVDSA and IADSA techniques. Mean sizes of the IVDSA aneurysm neck, width and height were 3.41±0.80 mm, 3.61±0.93 mm and 8.07±2.11 mm, respectively. Mean sizes of the IADSA aneurysm neck, width and height were 3.43±0.80 mm, 3.66±0.92 mm and 8.16±2.25 mm, respectively. No significant difference was found in the sizes of the aneurysm neck, width and height between the two groups (P=0.311, P=0.086 and P=0.258, respectively). IVDSA appears to be an alternative method for evaluating elastase-induced aneurysms in rabbits.     

Imaging of the digital arteries: digital subtraction angiography versus conventional arteriography

A retrospective study of 95 patients was undertaken to compare digital subtraction angiography (DSA) and conventional arteriography of the hand. Eighty patients had conventional angiography and 15 had DSA. In comparison with conventional angiography, DSA is more cost-efficient and facilitates outpatient angiography. It provides images as acceptable as those of conventional angiography. We conclude that intra-arterial DSA is now the procedure of choice for angiographic mapping of the digital arteries.     

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.     

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.     

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     

Imaging of aortoiliac arterial disease. Duplex ultrasound and MR angiography versus digital subtraction angiography

Purpose: To evaluate and compare the diagnostic accuracy of duplex ultrasound (US) and MR angiography (MRA) at 1.0 T in aortoiliac arterial disease using digital subtraction angiography (DSA) as the reference standard. In addition, a comparison of the 2D time-of flight (TOF) and 3D contrast-enhanced MRA (CE MRA) techniques was performed.Material and Methods: Prospectively, 39 patients with symptoms of lower-extremity arterial occlusive disease were examined using US, TOF MRA, CE MRA and DSA. Significant lesions (stenosis ≥50%) and occlusions were evaluated blindly for each method.Results: For all segments, the sensitivity for US, TOF MRA and CE MRA with regard to significant lesions was 0.72, 0.81 and 0.81, respectively, and the specificity for each was 0.97, 0.91 and 0.92, respectively. For significant lesions above the inguinal ligament the corresponding sensitivity was 0.84, 0.89 and 0.94 and the specificity 0.93, 0.82 and 0.73, respectively. The specificity was higher when the two MRA methods were combined. TOF MRA overgraded 7 segments as occluded. In most cases, the length of the occlusions was correctly determined on CE MRA, overestimated on TOF MRA and uncertain on US.Conclusion: Neither US nor MRA were sufficiently accurate to fully replace angiography. MRA was preferable to US as a non-invasive test when vascular intervention was contemplated. Although CE MRA was superior to TOF MRA, the most accurate results were achieved when the two methods were combined.     

The effect of scatter on densitometric stenosis measurements using an experimental digital subtraction angiography system

Purpose: To examine the effect of changing the experimental scatter condition on densitometric stenosis measurements.Methods: Experiments were conducted using an experimental digital fluoroscopic system. A test phantom with a known degree of stenosis was imaged before and after the introduction of an iodine-based contrast medium to simulate the digital subtraction angiography (DSA) process. The scatter to primary ratio has been reported to be affected by area irradiated, thickness of the part, kVp, and use of scatter reduction methods such as grids and airgaps. Each of these conditions were manipulated experimentally with densitometric stenosis measurements determined for each scatter condition.Results: Theoretically and experimentally, it is shown that the densitometric analysis produces a grossly inaccurate measurement of the degree of vessel stenosis when performed on images acquired under scatter conditions.     

Value of intra-arterial digital subtraction angiography

Among 3000 digital subtraction angiographies which have been performed in our institute, 850 patients have been examined intraarterially. The advantage of i.a. DSA is due to the excellent demonstration of vessels in survey angiograms by small amounts of contrast medium (10-20 ml in the aorta), without risk of selective catheterisation into the neck vessels, the saving of expensive film series, the short duration of vessel examinations and the small complication rate. I.a. DSA can be carried out on outpatients also, using the 4/5 F-catheter, which saves hospital charges. Impressive examples show the advantages of i.a. DSA.     

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.     

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.