Venous ultrasound

D-dimer this test may be a helpful adjunct to either a venous ultrasound or V/Q scan... 

Transcoronary venous injection is performed with a catheter system threaded percutaneously into the coronary sinus. Initial studies in swine have confirmed the feasibility and safety of this approach [121]. This delivery method has also been used to deliver skeletal myoblasts to scarred myocardium in cardiomyopathy patients [120]. With intravascular ultrasound guidance, this approach allows the operator to extend a catheter and needle away from the pericardial space and coronary artery into the adjacent myocardium. To date, human feasibility studies have had a good safety profile. This technique is limited, however, by coronary venous tortuosity, lack of site specific targeting, and its own technically challenging nature. Unlike the transendocardial approach, in which cells are... 

Golli, M., Kriaa, S., Said, M., Belguith, M., Zbidi, M., Saad, J., Nouri, A., Ganouni, A. Intrahepatic spontaneous portosystemic venous shunt value of color and power Doppler sonography. X. Clin. Ultrasound 2000 28 47-50... 

Lai, L., Brugge, W.R. Endoscopic ultrasound is a sensitive and specific test to diagnose portal venous system thrombosis (PVST). Amer. J. Gastroenterol. 2004 99 40-44... 

A major complication of intravenous infusion is thrombophlebitis, which is a principle limitation of peripheral parenteral nutrition. Its precise pathogenesis is unclear, but venospasm has been proposed as the most likely cause. However, in a study with ultrasound techniques to monitor vein caliber, there was no evidence to support this hypothesis, although thrombophlebitis was observed (10). The author suggested that the initiating event may be venous endothelial trauma, caused by the venepuncture itself, abrasion at the catheter tip, or the delivery of the feeding solution. 

Cabrera J, Redondo P, Becerra A, et al. Ultrasound-guided injection of polidocanol microfoam in the management of venous leg ulcers. Arch Dermatol 2004 140(6) 667-673. 

Horton KK (2005) Pathophysiology and current management of necrotizing enterocolitis. Neonatal Netw 24 37-46 Hurth PJ, Meyer JS, Shaaban A (2002) Ultrasound of a torsed ovary characteristic gray-scale appearance despite normal arterial and venous flow on Doppler. Pediatr Radiol 32 586-588... 

Using the contrast agent SonoVue, the microbubbles act as reflectors for the ultrasound beam enhancing backscatter beam. The agents remain in the circulation and, according to the perfusion phase (arterial, capillary, portal venous), lead to enhancement of different structures. This imaging modaUty allows an analysis of tumour perfusion under real-time conditions. 

Schulte-Altedorneburg G, Demharter J, Linn R et al (2003) Does ultrasound contrast agent improve the diagnostic value of colour and power Doppler sonography in superficial lymph node enlargement Eur J Radiol 48 252-257 Smith MD, Elion JL, McClure RR et al (1984) Left heart opacification with peripheral venous injection of a new saccharide echo contrast agent in dogs. J Am Coll Cardiol 13 1622-1628... 

Fig. 11.9. Expected ultrasound findings post ovarian vein embolization. Dilated adnexal veins remain but there is no accentuation of venous blood flow with Valsalva maneuver...

In vivo vasodilation Two methods observe the release of NO by the endothelium by measuring changes in blood flow in humans. In flow-mediated dilatation, the diameter of the brachial artery is measured with ultrasound. The vasodilation is induced by the increase of arterial shear stress after the release of an inflatable cuff around the arm. Plethysmography measures the blood flow via the volume changes of the forearm after venous occlusion. Quantification of NO is not possible in either method and the diagnostic value is limited as individuals show considerable variations in systemic response. 

Colour duplex ultrasound scanning is currently the technique of choice in order to assess the venous system of the lower limb. This technique combines ultrasound imaging with pulsated Doppler ultrasound, and provides detailed anatomic information of the superficial, deep, and perforating venous systems. It can identify specific veins in which blood reflux occurs, or obstructions which may be contributing to venous hypertension. 

Results of duplex and color Doppler sonography in the neck and arms are useful to demonstrate the presence or absence of venous flow,but overlying bone and lung severely hamper examination of mediastinal veins. The SVC can also be evaluated with transesophageal Doppler US, but the modality has a small field of view and is to some degree invasive and time-consuming (SvENSSON et al. 1991). Examination of the iliac veins and IVC is easier with duplex ultrasound, including demonstration of the hepatic and renal veins. 

Fig. 6.5. Ultrasound images of the axillary/ subclavian venous segment. Left, transverse images of the axillary artery (A.) and axillary vein (V.). (Published with permission of Lip-pincott, Williams and Wilkins). Right, longitudinal image of the axillary/subclavian vein...

Initial access into either the IJV or the SCV is gained with standard ultrasound guidance using micropuncture techniques. The 0.018-in. mandril guidewire is placed into the right atrium (RA). The tract is dilated over the mandril wire and then the non-tapered catheter is advanced over the wire until the tip is in the superior aspect of the RA. In patients with excessive soft tissue thickness, it is often difficult to directly insert the soft silicone non-tapered catheter. In these cases, it will be necessary to use a peel-away sheath to insert the catheter into the venous system. The catheter is fiushed, heparinized, and secured with no absorbable 3-0-suture material (Mauro and Weeks 1998b). 

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