PPT 1-3

Advances in ultrasound instrumentation has led to new ____ ____ ultrasound imaging modes which can improve the clinical utility of contrast-enhanced sonography.

"contrast-specific";

Advances in ultrasound equipment technology following the development of ultrasound contrast agents (UCAs) have resulted in new ___ ___ imaging modes, including grayscale methods, that allow _______________ without the limitations of Doppler US.

"contrast-specific"; detection of blood flow

Agents containing room (Albunex) air are commonly referred to as ___ ___ UCAs, whereas agents containing heavy gasses are referred to as ____ ___ agents.

"first-generation"; "second-generation"

This effect has been termed ____ ___ ___, _____ ____ ____ or simply ___ ___

"induced acoustic emission," "stimulated acoustic emission," "acoustic emission."

microbubble lie within in a range of _______ in diameter.

1-4 micrometers

Several recent reports have suggested that ____ can improve the assessment of hemangiomas

CES

____ ___ are common benign solid neoplasms of the liver and are frequently detected during hepatic US examinations.

Cavernous hemangiomas

For an agent to be clinically useful it should be: Currently, in the United States Optison, Definity, and Imagent) are ___ ___ for use in echocardiography.

FDA approved

In cases where the renal arteries are not visualized, the ___ ___ can improve the exam and potentially reduce the number of technically inadequate or otherwise non-diagnostic examinations.

IV contrast;

In 1998 ____ (FSO 69) became the second commercially available UCA in the United States.

Optison

___ has shown potential for use with grayscale harmonic imaging and Doppler modes for echocardiography as well as systemic vascular, tumor characterization, and abdominal applications.

Optison

contains a high-molecular-weight gas (perfluoropropane), which improves the stability and plasma longevity of the agent

Optison

___ ___ ____ differ from vascular agents in that the microbubbles of these agents are removed from the ___ ___ and taken up by or have an affinity toward specific tissues (e.g., the reticuloendothelial system (RES) in the liver and spleen, or thrombus).

Tissue-specific UCAs; blood pool

introduced by Gramiak and Shah in 1968

UCAs

_______ ____ ___ are gas-filled microbubbles that are administered intravenously to the systemic circulation

Ultrasound contrast agents (UCA's)

Contrast is likely to improve the detection of ___ ___ present in renal tumors and to identify ___ ___ that result from tumor thrombus in cases of renal vein or IVC involvement.

abnormal vessels; flow voids;

In their work, injected ___ ___ directly into the ascending aorta and cardiac chambers during echocardiographic examinations

agitated saline

The microbubbles formed by ____ resulted in strong reflections.

agitation

The majority of the development efforts involving HI have focused on gray-scale harmonic imaging (GSHI), which allows detection of contrast-enhancement of ___ ___ and organs with gray-scale US.

blood flow

Vascular contrast agents significantly increase the ability to visualize ___ ___ using color flow imaging and improve the intensity of spectral Doppler flow signals.

blood flow

Vascular or ___ ___ ultrasound contrast agents enhance Doppler (color and spectral) flow signals by adding more and better acoustic ____ to the bloodstream.

blood-pool; scatterers

Several different enhancement phases are observed following the ___ ___ of a contrast agent.

bolus injection

Harmonic imaging uses the same ___ ___ used for conventional sonography (the ultrasound system is configured to receive only echoes at the second harmonic frequency, which is twice the transmit frequency). ( e.g. 7.0 MHz for 3.5 MHz transducer)

broadband transducers;

In the future, liver lesion characterization may prove to be one of the most clinically valuable radiological applications of___ ___ ___.

contrast enhanced sonography

Over time, the presence of ___ ___ within or attached to the tissue changes its sonographic appearance.

contrast microbubbles

The clinical use of ___ ___ ___ has been shown to reduce or eliminate some of the current limitations of ultrasound imaging and Doppler blood flow detection.

contrast-enhanced sonography (CES)

Ingestion of ___ ___ has been used to improve sonographic examinations of the upper abdominal and retroperitoneal structures such as the pancreas.

degassed water

Vascular Ultrasound Contrast Agents: Sonographic detection of blood flow is limited by many factors, including: 1. the ___ __ ___ of a vessel 2. the ___ properties of intervening tissue 3. or ___ ___ flow.

depth and size; attenuation; low-velocity

The reflected echoes from the oscillating microbubbles contain ___ ___ at the fundamental frequency as well as at the higher and lower harmonics (subharmonics).

energy components

Limitations of ultrasound ___ ___ and the ___ ___ of Doppler are also factors that may impact the results of a vascular examination.

equipment sensitivity; operator dependence

Contrast-enhanced sonography also has been used effectively in the assessment of ____ ____ transjugular intrahepatic portosystemic shunts (TIPSs).

flow through

Vascular ultrasound contrast agents have been shown to ____ the detection of hepatic blood flow in normal subjects as well as patients with liver disease and ___ ___.

improve; portal hypertension

In most cases the benefits of using GSHI for CES (e.g., higher frame rates, ____ ___ ____, reduced artifacts) are so great that conventional (non-HI) color flow imaging is neither necessary nor advised.

improved contrast resolution

However, water simply displaces gas and traverses the gastrointestinal tract in an ____ and ____ manner

inconsistent; unpredictable

These phases can vary somewhat according to the ___ ___ ___ of the patient.

individual circulatory status

Other studies suggest that contrast-enhanced sonography is useful for evaluation of ____ ___ ___.

liver transplant recipients

Hepatic ultrasound blood flow studies are limited by _________ or for the detection of flow in the intrahepatic artery branches.

low-velocity blood flow

Other common abdominal/retroperitoneal applications of ultrasound include: ~Assessment of flow in the ___ ___ for mesenteric ischemia. ~The ___ ___ ___ arteries to evaluate suspected aneurysms, stenosis, or dissections. ~ IVC for evaluation of ____ ___ ___.

mesenteric arteries; aorta and iliac; filters or thromboses

In general, when a vascular agent's microbubbles are ruptured or otherwise destroyed the microbubble shell products are ____ or eliminated by the body, and the gas is ___.

metabolized; exhaled

That makes them smaller than red blood cells, which allows them to flow easily through the circulation as well as the _____.

microcirculation

For an agent to be clinically useful it should be: Have microbubbles or ___ that are small enough to traverse the___ ___ ___ (i.e., less than 8 microns in size);

microparticles; pulmonary capillary beds

For an agent to be clinically useful it should be:

nontoxic

When using a microbubble -based UCA, the microbubbles ____ (i.e., they get larger and smaller) when subjected to the acoustic energy present in the ultrasound field.

oscillate

If an appropriate level of acoustic energy is applied to the tissue, the microbubbles first ____ (emitting harmonic signals that can be detected with grayscale harmonic imaging) and then ___.

oscillate; rupture

Parenchymal injuries included ___ ___ that were not identified on baseline ultrasound, but were identified with contrast-enhanced sonography.

posttraumatic infarctions

The rupture of the microbubbles results in ___ ___ ___, appearing as a transient ___ of colors on a color Doppler display

random Doppler shifts; mosaic

When insonated after uptake, the stationary contrast microbubbles increase the ___ of the contrast-containing tissue.

reflectivity

The intact microbubbles may ___ ___ in the tissue for several hours.

remain stationary

Currently, tissue-specific agents that are taken up by the _____ system appear to be most useful in the assessment of patients with suspected ___ abnormalities (including the ability to both detect as well as characterize liver tumors using contrast-enhanced sonography).

reticuloendothelial; liver;

By changing the ___ ___ (or other acoustic characteristics) of normal and abnormal tissues, these agents improve the ___ of abnormalities and permit more specific sonographic diagnoses.

signal impedance; detectability;

Although ultrasound is usually sensitive for the detection of medium to large hepatic lesions, it is limited in its ability to detect ____(less than 10 mm), isoechoic, and/or ____ located lesions, particularly in obese patients or those with diffuse liver disease

small; peripherally;

For an agent to be clinically useful it should be: Be ___ enough to provide multiple recirculations

stable

Because tissue-specific ultrasound contrast agents target specific types of ___ and their behavior is ____, they can be considered in the category of ___ ___ ___.

tissue; predictable; molecular imaging agents

While the use of Doppler and power-Doppler imaging has improved the differential diagnosis of intrahepatic lesions over conventional B-mode imaging, _____ ___ ___ can provide crucial help in problem cases.

ultrasound contrast agents

Regardless of the shell or gas core composition, microbubble size is fairly ____.

uniform

Contrast-enhanced sonography may be useful for evaluating the ____ of autoimmune pancreatitis lesions and the therapeutic efficacy of steroid therapy.

vascularity;