Intravenous Angiography Research Articles

Computer simulation of image intensifier-based computed tomography detector: vascular application.

This present study reports the results of a computer simulation whose aim was to predict the low-contrast imaging performance of which a conventional x-ray image intensifier with charge coupled device (CCD) camera would be capable if incorporated into a computed tomography (CT) volume imager. A vascular imaging task was modeled in our simulation. The effects of detector noise, x-ray exposure levels, analog-to-digital conversion (ADC) precision and residual levels of detected x-ray scatter were considered. The results of this simulation indicate that the low-contrast imaging performance of an image intensifier-based CT system was most limited by the CCD detector readout noise. Given this limitation the detection of greater than about 100,000 detected photons/pixel/projection gave marginal improvement in low-contrast resolution. At these exposures 12 bit ADC precision resulted in little additional image noise. The effects of detecting scattered x rays are twofold; decreasing the signal-to-noise ratio associated with our modeled artery and introducing a cupping artifact. Based on the results from the simulation, it appears that an image intensifier-based CT system is a feasible concept from a noise viewpoint, if the anticipated imaging task is intravenous angiography.

Monitoring of pancreatic graft perfusion by first passage radionuclide angiography

The perfusion of two pancreatic transplants were examined three times a week for the first five postoperative weeks by intravenous angiography using 99Tcm-pertechnetate. Worsening of the perfusion always preceded or was associated with deterioration of the pancreatic function. Accordingly, radionuclide angiography may have an important place in the systematic monitoring of pancreatic transplants in the critical postoperative period.

Monitoring of Pancreatic Graft Perfusion by First Passage Radionuclide Angiography

The perfusion of two pancreatic transplants were examined three times a week for the first five postoperative weeks by intravenous angiography using 99Tcm-pertechnetate. Worsening of the perfusion always preceded or was associated with deterioration of the pancreatic function. Accordingly, radionuclide angiography may have an important place in the systematic monitoring of pancreatic transplants in the critical postoperative period.

A prospective study of vein patch angioplasty during carotid endarterectomy. Three-year results for 801 patients and 917 operations.

From 1983 through 1985, 801 consecutive patients (mean age: 66 years) underwent 917 primary carotid endarterectomies at the Cleveland Clinic. Conventional arteriotomy closure was performed during 483 operations, while patch angioplasty using a distal segment of saphenous vein was employed in 434. Preoperative risk factors, surgical management, and antiplatelet therapy were equivalent in the vein patch (VP) and nonpatch (NP) groups. Early results were evaluated by intravenous angiography (DSA) in 715 patients (89%), and 332 reconstructions (36%) have been reassessed by objective imaging during a mean follow-up interval of 21 months. Ischemic strokes occurred after 18 (1.9%) of the 917 procedures (0.7% VP, 3.1% NP; p = 0.0084), and symptomatic (N = 9) or unsuspected (N = 8) thrombosis of the internal carotid artery was confirmed by neck exploration or routine DSA after 1.9% of all operations (0.5% VP, 3.1% NP; p = 0.0027). Only ten patients (1.2%) have required reoperations for severe recurrent lesions, but the cumulative 3-year incidence of new defects (greater than or equal to 30% stenosis) documented by objective studies in the VP and NP groups was 9% and 31%, respectively (p = 0.0066). These results strongly suggest that VP angioplasty enhances the safety and durability of carotid endarterectomy.

Vessel imaging using dual-energy tomosynthesis.

A method has been developed that combines dual-energy subtraction and tomosynthesis for vessel imaging in intravenous angiography. This paper describes the procedure for doing tomosynthesis on a fan-beam rotational-motion system and gives the point responses of the imaging system. Phantom studies show that dual-energy tomosynthesis improves the visualization of desired vessels lying on a selected plane. The results may be feasible for some applications such as clinical diagnosis of coronary artery diseases.

Angiography in Non-Functioning Renal Allografts Receiving Cyclosporin A

During a two-year period angiography was performed in 10 out of 40 initially perfused kidney allografts within the first 3 postoperative weeks. Immunosuppression was in all cases performed with cyclosporin A. The indication for angiography was mainly deterioration in the graft function as judged from the renograms or inadequate demonstration of the graft during intravenous radionuclide angiography. At angiography, neither arterial nor venous occlusion was found, and it was normal in 5 patients. It is concluded that during cyclosporin A treatment angiography cannot be recommended on the above mentioned indications in the early postoperative period. A graft biopsy seems sufficient.

An attempt at coronary angiography with a large size monochromatic SR beam

The number of patients due to ischemic heart disease seems to be growing rapidly in Japan. Coronary angiography by Judkins' or Soncs' method is very invasive as is well known and thus imposes a burden on patients and physicians. The K-edge subtraction technique is considered to be applicable to intravenous angiography of coronary arteries. A feasibility study of K-edge subtraction with monochromatized SR has been initiated at Photon Factory since 1984. In 1985, a real time observation of intravenous angiography of a cat, utilizing a monochromatic beam with a size of 64 mm by 55 mm, was performed. This paper describes some results of our preliminary experiments and our future systems of clinical application.

Digital intravenous angiography for the study of hemodialysis vascular access.

Digital intravenous angiography is a simple and safe procedure and can be performed on an outpatient basis. Poor function of a hemodialysis vascular access due to increased graft resistance, reduced arterial inflow or shunt steal can be evaluated by this technique. Complications of direct graft puncture or conventional arteriography can be avoided using digital angiography.

The place of digital intravenous angiography in cerebral infarcts.

The authors describe their technique of intravenous digital subtraction angiography (IVDSA) and discuss the results in cerebral infarcts. IVDSA is a good first stage examination for the recognition of stenosis or occlusion of cervical vessels to the brain, as it is an only marginally invasive and easy technique. It is, however, good neither for the study of focal cervical not of intracranial areas.

The use of digitized intravenous angiography in a clinical setting: A retrospective review of 58 patients

Digitized intravenous angiography (DIVA) is a frequently used alternative to conventional intra-arterial angiography for the evaluation of cerebrovascular disease. In an attempt to identify factors that may increase the diagnostic capacity of DIVA, a retrospective study of 58 patients evaluated by DIVA for cerebrovascular disease was performed. The reason for the DIVA study was the presence of focal symptoms in 25 patients and nonfocal or vertebrobasilar symptoms in nine. Twenty-four patients were asymptomatic. DIVA was found to be adequately diagnostic in 37 patients (64%), and further evaluation was required in 21 (36%). When the 42 patients who had ocular pneumoplethysmography (OPG-Gee) results available were classified according to their presenting symptoms, 85% of those with focal symptoms and positive OPG-Gee had a diagnostically successful DIVA study. A high DIVA accuracy rate was also obtained in the asymptomatic patients, whether the OPG-Gee results were positive (60%) or negative (78%). The category of patients for whom the DIVA was the least successful was the group with nonfocal or vertebrobasilar symptoms. As many as 56% of these patients required additional testing. Thus it appears that the yield of diagnostic DIVA is increased when the clinical presentation and noninvasive testing are considered. A prospective study is underway to further verify this hypothesis.

Comparison of nephroangiotomography, intravenous subtraction angiography and digital subtraction angiography in the diagnosis of renal hypertension.

Nephroangiotomography (NATG), intravenous subtraction angiography (ISA) and digital subtraction angiography (DSA) were compared with regard to their specificity and diagnostic value, their expenditure of time, equipment and staff as well as to their risk for the patients. The interpretation of NATG is inferior to ISA. The hitting quota of ISA and DSA is equal. The expenditure of time and staff for ISA is important, whereas the equipment for DSA is considerable; however, it has a wider use. In case of a low patient number, ISA delivers sufficient results in the diagnosis of renal hypertension with the advantage that it can also be performed in smaller radiological institutes.

中枢性めまい症例に対するＤＳＡ（Ｄｉｇｉｔａｌ Ｓｕｂｔｒａｃｔｉｏｎ Ａｎｇｉｏｇｒａｐｈｙ）の応用

Digital subtraction angiography (DSA) is a recently developed non-invasive intravenous angiography which has become possible through real time digital subtraction of x-ray transmission data from an image intensifier and television system. The output signals of the image intensifier-television camera system are digitized by an analogdigital converter. The digital information, 512×512 pixels and 9 bits deep, is fed into the image processing assembly after logarithmic amplification, where 2-8 frames are added and subtracted from mask images for the final digital images. Intravenous digital subtraction angiography was performed in 21 patients with intractable dizzy spells of central origin resistant to treatment. These patients showed some signs of CNS disturbance, although there were no significant findings on CT scans.DSA resultsCases Percentagenormal 7 33.3abnormal 14 66.7unilateral vertebral obstruction 4 19.0stenosis 6 28.6reduced flow 2 9.5bilateral vertebral stenosis 2 9.5Surprisingly, findings were abnormal in 14 of 21 patients (66.7%).DSA is, therefore, considered to be an important aid in the diagnosis of vertigo of the central type.

Spontaneous dissecting aneurysms of the internal carotid and vertebral arteries--two case reports.

Two patients had acute spontaneous dissection of both internal carotid arteries and of one or both vertebral arteries. One had angiographic signs suggestive of fibro-muscular dysplasia and both were on oral contraceptives. They were treated with high dose heparin and made a good clinical recovery. A digital intravenous angiography performed two to three months later showed a complete recanalization of arteries involved. These patients are similar to those reported as "idiopathic regressing arteriopathy" and "reversible angiopathy" which probably correspond to the same entity.

Evaluation of asymmetries of blood flow rate and of circulation time by intravenous radionuclide cerebral angiography in patients with ischemic completed stroke.

155 patients with ischemic completed stroke of varying severity and outcome have been evaluated by radionuclide cerebral angiography with analysis of regional time-activity curves. Two parameters have been evaluated: area under the upslope of the curve (Aup) reflecting regional blood flow rate and moment of the whole curve reflecting tracer circulation time (rABCT) Combination of these two methods ensured increased detection of perfusion asymmetries.

Complications of digital intravenous angiography: experience in 2488 cervicocranial examinations.

All complications were recorded from the initial 2488 cases studied with digital intravenous angiography (DIVA) at New York University Medical Center. Mechanisms of producing these reactions were categorized into procedure-related, contrast-medium-related, or disease-related. The complications included extravasation of contrast material into the arm (11 patients) and mediastinum (two), acute pulmonary edema (four), hypotension (23), thrombophlebitis (two), and grand mal seizure (one). Recommendations are made that would allow DIVA to be performed more safely.

Extracranial carotid atherosclerotic vascular disease: Duplex sonography and digital subtraction angiography

Duplex sonography is an accurate method for evaluating the cervical carotid arteries. We feel it is the method of choice for screening asymptomatic patients or those with nonhemispheric symptoms. Patients with clear-cut TIAs or stroke, particularly those who are surgical candidates, need an angiogram. We have found preliminary duplex sonography helpful in determining whether intravenous or intraarterial DSA or conventional angiography will be the most efficacious examination for the patient. Duplex sonography is also an excellent noninvasive method for following patients with atherosclerotic disease or previous carotid endarterectomy.

Overview of Intracranial Applications of Digital Intravenous Angiography

The clinical utility of digital intravenous angiography (DIVA) in arteriosclerotic disease of the carotid arteries was reviewed in 86 patients. DIVA provides sufficient information for the evaluation of intracranial disorders in many individuals, particularly those with venous abnormalities. Arterial studies are still required when in-depth information is necessary with regard to abnormalities of the arterial system.

Results of intravenous digital subtraction angiography (IVDSA) as a screening method for renovascular hypertension.

Since January 1982 we have combined urography in hypertensive patients with intravenous angiography of the renal arteries. In more than 80% of 163 patients the examination was of good diagnostic quality and both renal arteries were well visualised. IVDSA has a lower morbidity and cost than conventional angiography. It is more accurate than urography and therefore offers better screening of a selected group of hypertensive patients.

The beneficial effects of short pulse width acquisition and ECG-gating in digital angiocardiography.

Experimental intravenous left ventriculography and coronary angiography after aortic root injection were performed in 13 animals. Various image acquisition and digital image processing techniques were employed. These included single mask mode subtraction, integrated mask mode subtraction, ECG-gated image acquisition, TV camera read-out in interlaced mode, and pulse progressive read-out with 1- to 5-ms pulse width. High quality images were obtained consistently only after ECG-gating and use of 1- to 5-ms pulse width with pulse progressive read-out of the TV camera. Integration of four to eight background as well as contrast images all from the same phase of the cardiac cycle further improved image quality.

Occlusive vascular disease in asphyxiated newborn infants

Six full-term severely asphyxiated newborn infants underwent evaluation with digital intravenous angiography. All infants were comatose and flaccid and had seizures, depressed brainstem function, and signs of intracranial hypertension. An initial brain CT scan revealed diffuse hypodensities and compressed ventricles. Follow-up noncontrast CT scans showed areas of increased attenuation. Digital intravenous angiography demonstrated venous sinus thrombosis in five infants, two of whom also had arterial thrombosis, and hypervascularity in the sixth infant. Our data document that occlusive vascular disease is a prominent feature of severe perinatal asphyxia.