Iliac vein stenting
Sachinder Singh Hans, Alexander D Shepard, Mitchell R Weaver, Paul G Bove, Graham W Long in Endovascular and Open Vascular Reconstruction, 2017
Diagnostic testing should focus on determining the etiology of CVI, in addition to determining the inflow and outflow of the affected segment. Such testing includes venous duplex ultrasound (US), air plethysmography, cross-sectional imaging (computed tomography venography (CTV)/magnetic resonance venography (MRV)), and ascending venography. Duplex US serves as a screening tool and helps to determine the extent of femoro-ilio-caval narrowing or obstruction based on luminal diameters in addition to providing reflux data; 12, 14, and 16 mm are the normal luminal diameter cutoffs used for the common femoral vein (CFV), external iliac vein (EIV), and common iliac vein (CIV), respectively (Table 16.1). Air plethysmography provides information on calf muscle pump function. Cross-sectional imaging, including CTV and MRV, elucidates venous anatomy, vein status vis-à-vis compression/occlusion, and collateral circulation. Abdominal and pelvic pathology, including malignancy, can also be evaluated by cross-sectional imaging. Ascending venography provides supplementary data on segmental inflow and outflow.
Venous anatomy and pathophysiology
Helane S Fronek in The Fundamentals of Phlebology: Venous Disease for Clinicians, 2007
Most vascular laboratories offer duplex ultrasound examination as the diagnostic test of choice. More than any other noninvasive diagnostic tool, duplex ultrasound has emerged as the most effective, cost-efficient, and reliable method to evaluate the peripheral venous system. This test, however, is very operator-dependent and thus prone to false-negative and -positive results. With duplex ultrasound imaging, the popliteal and femoral veins can be visualized and thrombi directly seen. The paired axial veins of the distal lower extremity (anterior tibial, posterior tibial, and peroneal veins) may not be as easily visualized, and require more expertise on the part of the sonographer. When ultrasound fails to confirm a suspected DVT, magnetic resonance venography (MRV) may be helpful.7 MRV is as accurate as contrast venography in visualizing DVT, can detect thrombi in pelvic veins that are not well visualized on DUS, and may provide a diagnosis if DVT is not present. Contrast venography has fallen out of favor, since it requires injection of contrast material that may cause an allergic reaction or renal damage. When definitive testing is not immediately available and the likelihood of DVT is high, the patient should be immediately fully anticoagulated while awaiting a definitive test. If a coagulopathy is suspected, appropriate blood tests should be drawn before anticoagulation is instituted.
Venous Thrombosis
Hau C. Kwaan, Meyer M. Samama in Clinical Thrombosis, 2019
Venography is an invasive procedure that is associated with significant foot and calf pain in some patients.103 The procedure may also be complicated by superficial phlebitis and even deep venous thrombosis in a small percentage (1 to 2%) of patients who have normal venograms.102,103 Other, less common complications of venography include hypersensitivity reactions to the radiopaque medium and local skin and tissue necrosis due to extravasation of dye at the site of injection.103 Many of the side effects of venography can be avoided by careful attention to technical detail, and by the use of isotonic radiopaque medium or by diluting the standard concentrated medium to 40%.
Atypical posterior reversible encephalopathy syndrome with albuminocytological dissociation and late emerging neuroradiological findings: A case report
Published in Postgraduate Medicine, 2021
Yaprak Ozum Unsal Bilgin, Neslihan Eskut, Asli Koskderelioglu, Muhtesem Gedizlioglu
The control of BP was achieved within 24 hours. The second CSF examination was done on the 3rd day of admission. The CSF opening pressure was high (290 mmH2O). The biochemical analysis of CSF revealed leukocyte count: 20/mm3, erythrocyte count: 300/mm3 and protein: 220 mg/dl. CSF protein levels were as high as in the initial examination. Cytological examination of CSF revealed no malignant cells. Blood testing for autoimmune encephalitis panel (NMDAR, AMPA1, AMPA 2, CASPR 2, LGI1, GABARB1 antibodies), serology testing for HIV, brucella and syphilis were negative. On the 6th day, cranial MRI showed hyperintense lesions consistent with vasogenic edema in T2-weighted images and fluid-attenuated inversion recovery (FLAIR) sequences in bilateral posterior parietal and occipital lobes (Figures 4, Figures 5). Flow was detected in all venous structures of MR venography imaging. Cranial MRI was repeated on the 6th day but due to the patient’s respiratory problems, the DWI sequences couldn’t be performed again. The patient was diagnosed with PRES according to the symptoms of admission, history of uncontrolled hypertension, presence of hypertensive crisis and radiological findings.
Advances in non-surgical treatment for pediatric patients with short bowel syndrome
Published in Expert Opinion on Orphan Drugs, 2020
Danielle Wendel, Beatrice E. Ho, Tanyaporn Kaenkumchorn, Simon P. Horslen
Although frequently used, venous ultrasonography may not be sensitive enough for surveillance or diagnosis of vascular occlusions but can be used to follow established lesions over time [63]. Venography is considered the diagnostic standard for accurate evaluation of venous patency although it is relatively invasive and requires specialized expertise [63]. Less invasive imaging studies such as CT and MR venography, when utilized by experienced centers, offer comprehensive information regarding venous obstruction. Treatment of thrombosis with low molecular weight heparin is typically recommended for 6 weeks to 3 months depending on the extent of the thrombus, thrombophilic factors, and response to treatment [64]. With the high risk of recurrence, many centers continue prophylactic anticoagulation until the central line is removed [65]. Warfarin is rarely used in SBS patients secondary to significant malabsorption, the difficulties of frequent laboratory monitoring, and the challenges of removing vitamin K from PN without affecting other trace nutrients.
A sickle cell disease patient with dural venous sinus thrombosis: a case report and literature review
Published in Hemoglobin, 2019
Michael K. Wang, Ravi Shergill, Matthew Jefkins, Jason Cheung
Diagnosis of DVST relies heavily on imaging to identify the presence of a thrombus in the dural venous sinuses. Non-contrast CT scans demonstrate abnormalities in only 30.0% of cases, and hence, are often initially missed. Hyperdensity in the posterior aspect of the superior sagittal sinus (‘dense triangle sign’) and ischemic lesions crossing arterial boundaries are common findings indicative of DVST on plain CT [30]. On contrast-enhanced CT, thrombus in the superior sagittal sinus is often visualized as a central hypointesity surrounded by contrast enhancement with a triangular shape (‘empty-delta sign’). Thrombi may appear isodense in the subacute or chronic setting, and in such cases CT venography is often helpful. If available, magnetic resonance imaging (MRI) combined with venography (MRV) is preferred as it is more sensitive than CT. Ischemic events occurring in the direct vicinity of the venous duct are particularly often better appreciated on MRI compared to CT. More invasive methods of diagnosis, such as cerebral angiography and direct cerebral venography, are rarely used [31].
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