Introduction There have been impressive advances recently in the application of ultrasound contrast medium to liver imaging; but these agents are not universally available. Researchers have shown the benefits of microbubble-enhanced lesion detection and characterisation. Unfortunately governing agencies across the…
Arteriovenous Fistulas and Synthetic Arteriovenous Grafts At the end of 2009, there were 571,414 patients being treated for end-stage renal disease in the United States with 116,395 new cases in that year ; approximately 65% of these patients received haemodialysis.…
Doppler examination in the abdomen is associated with specific problems which are not encountered in peripheral vascular examinations and these are particularly relevant to examinations of the aorta, inferior vena cava and their associated vessels. Respiratory motion and cardiac pulsation…
The peripheral veins may be affected by a variety of disorders which can be assessed by ultrasound. Deep vein thrombosis (DVT) and thromboembolic disease are the most common indications for investigation of the peripheral veins but venous insufficiency and vein…
Atheroma occurs to different degrees in different parts of an individual’s cardiovascular system and the lower limb arteries are particularly prone to the development of atherosclerosis. Approximately 2% of adults in late middle age in Western countries have intermittent claudication…
The Carotid and Vertebral Arteries CAROTID DISEASE AND STROKE Stroke is a major cause of morbidity and mortality. In the United Kingdom, there are approximately 150 000 first strokes each year and some 53 000 deaths a year as a…
Principles of Blood Flow This section describes the simple principles of blood flow which are of value in understanding the role of Doppler and for performing vascular ultrasound examinations. The underlying principles of fluid mechanics applied to the flow of…
A number of techniques have been developed which exploit the shift in frequency of ultrasound when it is reflected from moving blood. This frequency shift is known as the ‘Doppler effect’. Five types of diagnostic Doppler instrument are usually distinguished:…