Vascular ultrasound

Fig. 5 J Intracardiac Ultrasound for Vascular Access. Use of vascular ultrasound to gain access to the axillary vein can greatly facihtate left ventricular lead implantation by improving vascular access at the beginning of the procedure. Typical ultrasound probes have frequencies of 7.5 or 9 MHz (a). The higher frequency probes are better for access for more superficial vascular structures like those in the neck, whereas the lower frequency 7.5 MHz transducers permit acceptable imaging of the axillary, cephahc and portions of the subclavian veins. Ultrasound gel must be placed inside the plastic probe cover to gain acceptable images (b, Panel A). The plastic cover is secured with sterile rubber bands (b, Panel B). To differentiate to the axillary vein (V) from artery (A), gentle compression is applied to the vessels, causing the vein to collapse while the artery does not (c).

Vascular ultrasound has also greatly facilitated the implant process by easing axillary vein localization. Commercially available systems (Site Rite , Bard Access Systems, Salt Lake City, UT) include either a 9 or 7.5 MHz ultrasound probe to localize the axillary artery and vein. Differentiating the vein from artery is easily accomplished by compressing the structures with probe and noting which collapses more easily (Fig. 5.3). In patients with elevated right heart pressures, this same effect can be facilitated by having the patient inspire forcefully. 

Ferring M, Claridge M, Smith SA, Wilmink T Routine preoperative vascular ultrasound improves patency and use of arteriovenous fistulas for hemodialysis a randomized trial. Chn J Am Soc Nephrol 2010 5 2236-2244. Malovrh M Native arteriovenous fistula preoperative evaluation. Am J Kidney Dis 2002 39 1218-1225. 

Jemcov TK Morphologic and functional vessels characteristics assessed by ultrasonography for prediction of radiocephahc fistula maturation. J Vase Access 2013 14 356 363. Ferring M, Henderson J, Wilmink T, Smith S Vascular ultrasound for the pre-operative evaluation prior to arteriovenous fistula formation for haemodialysis review of the evidence. Nephrol Dial Transplant 2008 23 1809-1815. 

Sikdar et al. (2004) have used vascular ultrasound to record arterial wall vibrations from ex vivo 3.1 mm lamb arteries that have been partially ligated to model a 40% stenosis. Flow is provided from a pulsatile pump to match flow in a human artery. The apparatus was used to generate stenosis-induced sounds and were recorded by both ultrasound recording of vascular sounds and a fiber-optic microphone. To illustrate the frequency content microphone records a Fourier transform was applied to the microphone data to provide spectral data for both the ultrasound and Doppler records. 

Norris JW, Halliday A. Is ultrasound sufficient for vascular imaging prior to carotid endarterectomy Stroke 2004 35(2) 370-371. 

Fleischer AC. Sonographic depiction of tumor vascularity and flow. J Ultrasound Med 1999 19 55-61. 

Gonadotropins are used to treat infertility in women with potentially functional ovaries who have not responded to other treatments. The therapy is designed to simulate the normal menstrual cycle as far as is practical. A common protocol is daily injections of menotropins for 9 to 12 days, until estradiol levels are equal to that in a normal woman, followed by a single dose of hCG to induce ovulation. Two problems with this treatment are risks of ovarian hyperstimulation and of multiple births. Ovarian hyperstimulation is characterized by sudden ovarian enlargement associated with an increase in vascular permeability and rapid accumulation of fluid in peritoneal, pleural, and pericardial cavities. To prevent such occurrences, ovarian development is monitored during treatment by ultrasound techniques and by measurements of serum levels of estradiol. 

ACS represents a prothrombotic state not just confined to the culprit lesion, with evidence of a pan coronary process and generalized platelet activation. Multiple vulnerable plaques in nonculprit vessels have been identified by angioscopy or intravascular ultrasound in ACS. Protracted treatment with clopidogrel induces antiplatelet activity that provides early benefits, and may limit thrombotic events within the following months. In the CURE study, the curves of major vascular events continue to diverge and showed an additional benefit from one-month follow-up to one year. 

Sabate M, Serruys PW, van der Giessen WJ, et al. Geometric vascular remodeling after balloon angioplasty and /3-radiation therapy a three-dimensional intravascular ultrasound study. Circulation 1999 100 1 182-1 188. 

Schmahmann JD (2003). Vascular syndromes of the thalamus. Stroke 34 2264-2278 Schulz UG, Rothwell PM (2001). Major variation in carotid bifurcation anatomy a possible risk factor for plaque development Stroke 32 2522-2529 Scott BL, Jankovic J (1996). Delayed-onset progressive movement disorders after static brain lesions. Neurology 46 68-74 Wardlaw JM, Merrick MV, Ferrington CM et al. (1996). Comparison of a simple isotope method of predicting likely middle cerebral artery occlusion with transcranial Doppler ultrasound in acute ischaemic stroke. Cerebrovascular Diseases 6 32-39 Wardlaw JM, Lewsi SC, Dennis MS etal. (1999). Is it reasonable to assume a particular embolic source from the type of stroke Cerebrovascular Diseases 9(Supp 1) 14... 

Gronholdt MLM (1999). Ultrasound and lipoproteins as predictors of lipid-rich rupture-prone plaques in the carotid artery. Arteriosclerosis Thrombosis and Vascular Biology 19 2-13... 

Traditional examination alone may not always be adequate to diagnose or manage scleritis, to identify areas of early vascular closure (see Figure 28-6), to differentiate benign nondestructive scleritis from necrosis, or to adequately monitor the success of treatment. Although not readily available, high-frequency ultrasound biomicroscopy... 

Cedrone, A., Pompili, M., Sallustio, G., Lorenzelli, G.P., Gasbarrini, G., Rapaccini, G.L. Comparison between color power Doppler ultrasound with echo-enhancer and spiral computed tomography in the evaluation of hepatocellular carcinoma vascularization before and after ablation procedures. Amer. J. Gastroenterol. 2001 96 1854-1859... 

Gaiani, S., Volpe, L., Piscaglia, F., Bolondi, L. Vascularity of liver tumours and recent advances in Doppler ultrasound. J. Hepatol. 2001 34 474-482... 

Based on postmortem findings in a 32-year-old woman who died with an acute encephalopathy (30) and another report of two patients investigated with tran-scranial Doppler ultrasound and MRI for symptoms of ciclosporin nenrotoxicity (31), vascular changes with vasospasm and dissection of the vascular intima strongly snggest that vascnlopathy is a possible mechanism of ciclosporin-indnced encephalopathy. 

Assessment of vascularity can be useful in differentiating benign and malignant breast lesions using color Doppler examination. However, some neoplasms have low blood flow and Doppler may be suboptimal. In these cases, ultrasound contrast may be beneficial. In a phase II/III, multicenter, randomized study 220 patients... 

It has been known for more than 100 years that patients with kidney failure have vascular calcification. In 1855, Virchow noted that vascular calcification is an ossification, and not a mere calciiication. Serial x-ray studies and ultrasound imaging of large arteries confirm increased calcification in patients on dialysis over many years.Studies from France have linked the presence of vascular calcification with reduced survival on dialysis. ... 

Most recently, low-intensity ultrasound has been used to enhance gene transfection by liposome.139 In this study, ultrasound exposure (1 MHz, 0.4 W/cm2) for 60 seconds enhanced transfection of naked or liposome-complexed luciferase reporter plasmid into cultured porcine vascular smooth muscle and endothelial cells. These results with liposome-complexed reporter plasmid are similar to those of Unger et al., who showed that relatively low levels of ultrasound energy (0.5 W/ cm2) enhanced gene expression.140 In these two studies, ultrasound exposure did... 

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