…Asymptomatic disease Many patients with carotid stenosis have no focal neurological symptoms. Asymptomatic disease may be discovered during targeted duplex ultrasound (DUS), pre operative assessment…

…is decided before the needle goes in: the choice of site, the use of ultrasound throughout the puncture, and maintaining maximal barrier precautions without shortcuts…

…other underlying cause immediately. 9. Request ultrasound of the kidneys and urinary tract when a postrenal cause cannot confidently be excluded. 10. Contact nephrology early…

…Gallstone causing acoustic shadowing. Reverberations artifacts Ultrasound waves can be reflected multiple times between dense structures ( i.e structures with high echogenicity). For each reflection…

…As can be seen from Figure 2, the ultrasound transducer contains several components. The transducer contains acoustic insulation that ensures that no other sound waves…

Echocardiography Principles of image optimization in echocardiography In order to obtain optimal ultrasound images, it is necessary to adjust several parameters continuously during the examination…

Echocardiography Basic sound and ultrasound physics Unlike light waves, which can propagate through vacuum, sound waves can only propagate through a physical medium. This medium…

…take longer to reach the transducer. Ultrasound waves reflected from the same structure can reach the different crystals at different time points . To solve this…

Echocardiography Calculation of hemodynamic parameters by ultrasound Hemodynamics is the study of blood flow dynamics. The physical laws that govern blood flow are fundamental in…

…sequence of activation of the piezoelectric crystals. The density of the ultrasound lines decreases with increasing distance from the transducer; this affects the lateral resolution…

…Doppler (CW Doppler), ultrasound waves are continuously emitted from the transducer and the reflections of these waves are analyzed continuously (Figure 1). This is possible…

Echocardiography Pulsed Wave Doppler The pulsed wave Doppler (PW Doppler) sends short pulses of ultrasound and analyzes reflected sound waves between the pulses. This is…

…renal failure or simply deterioration. The procedure itself is straightforward: ultrasound to find the fluid, an insertion site in the left lower quadrant lateral to…

…and intubation can precipitate circulatory collapse in a tamponaded patient , since positive airway pressure further reduces the venous return. Procedure Choice of access The ultrasound…

…Bedside ultrasound immediately before the puncture markedly reduces the risk of pneumothorax and is now the standard — puncture on the basis of percussion and a…

…thrombus, and implanted stents. The principal modalities used in the catheterization laboratory are intravascular ultrasound (IVUS) and optical coherence tomography (OCT). Unlike coronary angiography, which…

…Ryan Lafollette and Bill Hinckley run this amazing website which includes everything from ultrasound knobology and emergency procedures to practice guidelines for emergency medicine (and…

…and ultrasound studies are now performed in the majority of patients with stroke or TIA. The purpose of performing an ultrasound is to scrutinize potential…

…ventricular mass. Most formulas are simple mathematical equations, included in all ultrasound systems, and assume that the geometry of the left ventricle is normal. Figure…

…line over time (the x axis displays time). Since M mode only analyzes a single ultrasound line, its temporal and axial resolution is very high…

…child in the supine position. This is possible due to the small distance between the heart and the ultrasound transducer, and because less air filled…

…Moreover, the ultrasound system performs several calculates based on these parameters (e.g adjusting various dimensions/volumes to body surface area). Heart rate and blood…

…shift. To analyze reflections from the myocardium, the ultrasound machine filters out all other reflected sound waves, such that only those representing myocardium are recorded…

…picture without a demarcated fluid collection. Ultrasound also shows the depth of the cavity and its distance to vessels. Contraindications and when to involve a…

…Preparation and equipment Equipment: a handheld Doppler probe 5–10 MHz, ultrasound gel, a blood pressure cuff of the correct size (the width should correspond…

…However, intravascular ultrasound has shown that delayed opening of the bridged segment may extend into diastole, so the physiological effect is not limited to systole…

…Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) provide cross sectional information about plaque morphology and may clarify the mechanism of an acute coronary syndrome…

…reserve (CFVR) Pulmonary congestion detected by B lines on lung ultrasound Myocardial perfusion when ultrasound contrast agents are used The technique is particularly useful because…

…cardiac index is cardiac output normalized to body surface area. The ultrasound system calculates body surface area using the patient's sex, weight and height…

…patience, and correct instrumentation settings. Technical aspects of optimization of image quality have been discussed previously (refer to Optimization of the Ultrasound Image). Additionally, a…

…the Bernoulli principle, the sum of kinetic energy (K) and pressure energy (P) is constant as blood flows through the circulatory system. The equality of…

…mmHg , which provides a continuous slow flush. Ultrasound with a high frequency linear probe when the pulse is weak, after previous failed attempts, or in…

…TSH and coeliac serology , together with ultrasound of the liver and biliary tract . Go through the medication and any herbal preparations carefully — drug induced liver…

Procedurer In acute circulatory failure it is not the number of cannulae that matters but the flow per unit time . A large bore, short cannula…

…persisting risk factor, or recurrence. Special situations Situation Comment : : Pregnancy Leg ultrasound first. CT pulmonary angiography or lung scintigraphy according to local procedure. Low molecular…

…In patients with AAA, duplex ultrasound screening for femoropopliteal aneurysms should be considered. Opportunistic screening may also be useful in patients with symptomatic or asymptomatic…

…or dissection. Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) can reveal lesions that are not apparent on conventional angiography. Coronary vasomotor disorders may involve…

…Large variations in velocities recorded within a single sample volume indicate turbulent flow; the ultrasound machine is programmed to depict such flows with green color…

…reflectors move towards each other, sound waves are compressed and vice versa . Erythrocytes reflect ultrasound waves. Because erythrocytes are small, round and have an irregular…

…time to describe how echocardiography (M mode) can be used to diagnose endocarditis. With 2D and later 3D ultrasound, the technology has been greatly refined…

…to 50 ml of liquid. This volume is so small that the pericardial space is usually not visible on ultrasound (alternatively, a few millimeters of…

…in the valve orifice. The ultrasound machine displays the recorded flows as the spectral curve (Pulsed wave Doppler or Continuous wave Doppler). The area within…