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Vascular Access
Published in James Michael Forsyth, How to Be a Safe Consultant Vascular Surgeon from Day One, 2023
Final question. You have mentioned duplex ultrasound and catheter angiography for investigating fistulas that are failing to mature. What other radiological options are available?“There is CT angiography and MR angiography. These can be considered, but there are potential risks. CT uses iodinated contrast and has a radiation risk. Contrast enhanced MR carries a theoretical risk of causing nephrogenic systemic fibrosis. Henceforth, if these are going to be used, it should only be after carefully weighing the risks and benefits of alternative imaging studies.”
Neurological Disease
Published in John S. Axford, Chris A. O'Callaghan, Medicine for Finals and Beyond, 2023
CT: This shows blood in the subarachnoid space in 99% of cases if performed within 6 hours and may suggest which vessel has bled. Patients with a positive CT should undergo immediate CT angiography, to guide management. Later CT may detect complications such as hydrocephalus, haematoma and infarction.
Clinical Applications of Photon-Counting Detector Computed Tomography
Published in Katsuyuki Taguchi, Ira Blevis, Krzysztof Iniewski, Spectral, Photon Counting Computed Tomography, 2020
Shuai Leng, Shengzhen Tao, Kishore Rajendran, Cynthia H. McCollough
CT angiography is a well-established technique that has been frequently utilized for the noninvasive evaluation of vasculature, detection of cerebral aneurysms, arterial stenosis, and other vascular anomalies. It is also widely used for preoperative evaluation.
Giant cell arteritis
Published in Postgraduate Medicine, 2023
CT/CT-CT angiography (CTA) is a frequently used imaging method for aortic pathologies but lacks the spatial resolution necessary for visualization of the temporal arteries. CTA depicts the vessel lumen using luminal contrast agents and is best for visualizing changes in the vascular lumen such as irregular contour, stenosis or aneurysms and detailed vessel wall characterization including extent of mural thickening. CT can demonstrate concentric mural thickening over long segments indicative of LV involvement. Aortic wall thickness greater than 2.2 mm on CT scan in a case control study of 64 GCA patients was 67% sensitive and 98% specific for the diagnosis of GCA [120] although with the inability to obtain histological correlation, such cutoffs remain a matter of debate. CT and CTA have a reported sensitivity of 73% and specificity of 78% for the diagnosis of LV-GCA with clinical diagnosis as the reference standard [121].
Long term use of anticoagulant therapy for patients with pulmonary embolism
Published in Expert Review of Hematology, 2020
Cecilia Becattini, Ludovica Anna Cimini
Residual pulmonary vascular obstruction has been proposed to predict the risk for VTE recurrence after PE [49–55]. A recent meta-analysis confirmed an association between the presence of residual pulmonary vascular obstruction and the risk of VTE recurrence (OR 2.17; 95% CI 1.59–2.96; I2 23%) [56]. Despite these results, the role of residual pulmonary vascular obstruction in decision-making on long-term anticoagulant treatment remains debated. The main limits of this approach are the uncertainty on the best imaging test for assessment of residual emboli and recurrent PE (computed tomography vs perfusion lung scan), timing for assessment and definition of residual obstruction. Moreover, concerns on radiation exposure, increased risk of renal toxicity after administration of contrast media and the costs of CT angiography represent the main counterbalance for this approach. Currently, available evidence cannot support routine assessment of residual vascular obstruction after PE.
Acute type A aortic dissection – a review
Published in Scandinavian Cardiovascular Journal, 2020
Tomas Gudbjartsson, Anders Ahlsson, Arnar Geirsson, Jarmo Gunn, Vibeke Hjortdal, Anders Jeppsson, Ari Mennander, Igor Zindovic, Christian Olsson
Prompt diagnosis based on early suspicion of ATAAD is mandatory for successful treatment. Conventional chest X-ray can show a wide mediastinum, which is not specific for diagnosis [27]. The quickest and most accurate method, however, of confirming the diagnosis is CT scanning of the aorta [50]. The aim is to visualize the true and the false lumen of the aorta during dissection, to identify tears of the intima in-between the lumen, and to evaluate the extent of the dissection and the involvement of the branching arteries of the aorta including the arch vessels (Figure 2(b)). CT also aids in the planning of the surgery and cannulation sites. The sensitivity and specificity of CT are excellent [50], but in patients with poor renal function or allergy to iodinated dye, CT angiography is questionable and other imaging modalities such as magnetic resonance imaging (MRI) or ultrasonography can be considered instead. On the other hand, MRI is seldom used―as it is too time-consuming and still often unavailable, but it may complement CT angiography in follow-up imaging of the aorta [51].