Search results for "Subtraction"
showing 10 items of 112 documents
Prospective comparison of CT angiography of the legs with intraarterial digital subtraction angiography.
1996
The aim of this study was to determine the accuracy of CT angiography (CTA) with a single spiral acquisition for the diagnosis of arterial stenoses and occlusion in patients with peripheral vascular occlusive disease.In a prospective study, intraarterial digital subtraction angiography and i.v. CTA from the groin to the lower calves were performed on 50 patients with vascular occlusive disease. Maximum-intensity-projection images in multiple views were produced. The accuracy of CTA with and without analysis of the axial scans was determined with digital subtraction angiography as the standard.The sensitivities of CTA were 100% for the diagnosis of femoral artery occlusion, 100% for the dete…
Radiation exposure in vascular angiographic procedures.
2012
Abstract Purpose To evaluate dose reduction in vascular angiographic procedures by using fluoroscopy capture instead of digital subtraction angiography frames for documentation. Materials and Methods A total of 764 consecutive vascular interventional procedures performed over a period of 1 year were retrospectively analyzed with respect to the fluoroscopy time and the resulting dose–area product (DAP), the DAP of the radiographic frames, and the overall DAP. Results A total of 70% of the total DAP was a result of the acquisition of radiographic frames, leaving only 30% being applied by fluoroscopy. Conclusions Fluoroscopy capture should be used for documentation whenever possible. A registr…
Localization of small islet-cell tumors. Preoperative and intraoperative ultrasound, computed tomography, arteriography, digital subtraction angiogra…
1985
A total of 42 islet-cell tumors were examined between 1972 and 1984. Problems of localization were only encountered in 31 tumors less than 2 cm in diameter. Of 31 small tumors, 27 were correctly localized using a combined diagnostic approach: ultrasound was successful in 12/20 tumors, CT in 9/21, angiography in 20/31, intraarterial digital subtraction angiography in 1/2, and pancreatic venous sampling in 13/16. The smallest tumor found by ultrasound and CT was 7 mm in diameter. Intraoperative ultrasound demonstrated all 9 insulinomas examined. Currently, the most useful techniques for localizing small islet-cell tumors are ultrasound, CT, and angiography. CT is particularly useful for tumor…
Right ventricular volume determination in isolated human hearts
1986
For right ventricular volume determination a new method was developed that took into account right ventricular imaging by apical two-dimensional echocardiography in the four- and two-chamber views. Right ventricular volume was calculated by subtraction of the partial volume of the left ventricle and interventricular septum from the total heart volume of the right and left ventricles including the interventricular septum. Accuracy of the subtraction method was evaluated in isolated human hearts by two-dimensional echocardiography and radiography. Regression analysis indicated that for both the echocardiographic and radiologic procedures, the subtraction method gave the best correlation with …
Implementation of computed tomography angiography (CTA) and computed tomography perfusion (CTP) in Polish guidelines for determination of cerebral ci…
2021
Background: Brain death/death by neurologic criteria (BD/DNC) guidelines are routinely analyzed, compared and updated in the majority of countries and are later implemented as national criteria. At the same time, extensive works have been conducted in order to unify clinical procedures and to validate and implement new technologies into a panel of ancillary tests. Recently evaluated computed tomography angiography and computed tomography perfusion (CTA/CTP) seem to be superior to traditionally used digital subtraction angiography (DSA), transcranial Doppler (TCD) and cerebral perfusion scintigraphy for diagnosis of cerebral circulatory arrest (CCA). In this narrative review, we would like t…
Basics of Image Interpretation in Interventional Neuroradiology
2011
The majority of patients with cerebral vascular diseases, demanding neuroradiological interventions are those, who present with potential life-threatening spontaneous intracranial/intracerebral haemorrhages due to cerebral aneurysms or/and arteriovenous malformations (AVMs) or with cerebral infarction due to intra-arterial thrombi in cerebral arteries. Neuroradiological procedures (interventional neuroradiology) (IN), always, performed in general anaesthesia can be divided into occluding and opening interventions.
Kontrastmittelgestützte 3D-MR-Angiographie der Becken- und Beinarterien mit automatischer Tischverschiebung bei 1,0 Tesla
2000
PURPOSE Assessment of the value of contrast-enhanced MR angiography (ceMRA) using an automatic tracking technique at 1.0 Tesla in comparison with digital subtraction angiography (DSA) of the pelvic and lower limb arteries. MATERIALS AND METHODS In 15 patients with peripheral arterial occlusive disease a ceMRA (3D FLASH, TR/TE = 6.2/2.3 ms, Flip angle alpha = 30 degrees, Matrix 170 x 256) using a new automatic tracking technique was accomplished. The reference method was DSA. Twenty-one vessel segments of each patient were graded as normal, stenosed (> 50%) or occluded. Image material was evaluated independently by two radiologists. RESULTS In comparison, the interobserver agreement showed a…
Softwareassistierte CT-Nachverarbeitung am Beispiel der Karotiden
2004
Ziel der Arbeit: Es sollte ein Softwareassistent fur die automatisierte Auswertung von CT-Angiographien entwickelt werden, der die Visualisierung des Gefaslumens und eine quantitative Auswertung von Stenosen ermoglicht. Die klinische Erprobung erfolgt am Beispiel der A. carotis. Methodik: Bei insgesamt zwolf Patienten mit Verdacht auf eine hohergradige Stenose der Karotiden wurde eine CT-Angiographie (CTA) mit einem Mehrzeilen-CT durchgefuhrt. Diese Daten wurden mit dem neuen Softwareassistenten analysiert und ausgewertet. Die Ergebnisse verglich man mit der digitalen Subtraktionsangiographie (DSA). Ergebnisse: Die Nachverarbeitungszeit der CT-Datensatze mit Hilfe des Softwareassistenten li…
Parametric assessment of myocardial perfusion by densitometric evaluation of digital subtraction coronary angiograms: a comparison with tomographic T…
2002
Densitometric results about local myocardial perfusion are compared with those derived from a quantitative analysis of TL-201 single photon emission computer tomograms (TL-201 SPECT). Ten patients underwent conventional TL-201 SPECT at rest and after maximum bicycle stress and dipyridamole infusion the day prior to the investigation. SPECT was applied to provide improved spatial resolution for the detection of perfusion abnormalities. During the catheterization procedure four digital subtraction coronary angiograms were performed, two of the left and two of the right coronary artery both before and after pharmacologically induced hyperemia by intracoronary papaverine. The densitometric para…
Interdisciplinary management of peripheral arteriovenous malformations: review of the literature and current proceedings.
2021
Arteriovenous malformations (AVMs) are a rare congenital vascular disorder. They represent a fast-flow vascular malformation. Clinically, AVMs present a heterogenous expression and can affect every part of the body. Here, we will solely focus on extracranial AVMs. Generally, AVMs progress with the patient's age. Patients often suffer from pulsation, skin discoloration, pain, ulceration, bleeding, and disfigurement. Diagnostic tools include color-coded duplex sonography, MRI and CT imaging, as well as the clinical examination. 4D dynamic perfusion-computed tomography may help in the interventional planning. Digital subtraction angiography is required during interventional therapy. AVMs pose …