Type:
Educational Exhibit
Keywords:
Contrast agent-intravenous, Biopsy, Ablation procedures, Ultrasound, Percutaneous, Interventional non-vascular, Contrast agents, Abdomen, Cancer
Authors:
A. Gonzalez Lopez1, J. Puig Domingo2, X. Serres3, F. Novell Teixidó1, N. Roson3, B. Consola1, M. Sola Garcia1, J. M. Escudero Fernandez3; 1Sabadell/ES, 2Sabadell, Barcelona/ES, 3BARCELONA/ES
DOI:
10.26044/ecr2019/C-2110
Background
Ultrasound contrast agents contain microbubbles that increase the signal after they are administered into the bloodstream or into a body cavity.
To evaluate the liver,
the most common ultrasound contrast agent is sulfur hexafluoride stabilized with different surfactants (phospholipids and palmitic acid),
commercialized under the name SonoVue® and administered intravenously.
The microbubbles are similar to or smaller than red blood cells in size (1-10 µm),
allowing them to circulate through the capillary bed without crossing the endothelium; thus,
unlike the contrast agents used in computed tomography (CT) or magnetic resonance imaging (MRI),
the contrast agents used for CEUS are purely intravascular.
When the ultrasound beam comes into contact with the microbubbles,
they oscillate,
contracting during the compression part of the cycle and expanding during the rarefaction part of the cycle,
emitting sound.
The most commonly used method of detecting the signal from microbubbles is pulse inversion.
Main advantages:
-
Real-time evaluation of lesion hemodynamics: lesion uptake can be evaluated in real time,
ensuring that the study includes true arterial and venous phases (unlike in CT and MRI,
where this cannot be guaranteed).
-
Quantitative assessment: although most studies are qualitative,
commercial software enables quantitative evaluation,
increasing objectivity and precision.
Quantitative assessment of the response to anti-angiogenic drugs is especially useful in some oncologic patients.
-
Evaluation of the macro- and micro-circulation: since ultrasound contrast agents are purely intravascular,
they circulate through all blood vessels,
from the great vessels to the capillaries.
-
Very few secondary effects: ultrasound contrast agents are very safe and can be used in patients in whom CT and MRI contrast agents are contraindicated.
-
Multiple administration in a single session: thanks to their excellent safety and tolerability,
ultrasound contrast agents can be administered multiple times in a single study,
if necessary.
Main disadvantages:
-
It is difficult to study more than one lesion at a time,
which limits staging.
-
CEUS is not recommended for very deep lesions or for those that cannot be seen in B mode.
-
The technique is operator-dependent; there is a learning curve not only for interpreting images,
but also for acquiring them.
The ACR’s LIRADS® and the EFSUMB’s guidelines help standardize image acquisition and interpretation and minimize variability.
Contraindications:
-
Hypersensitivity
-
Some heart conditions: recent (<6 months) acute myocardial infarction,
NYHA grade III-IV heart failure,
or severe arrhythmias.
-
Severe pulmonary hypertension.
-
Acute respiratory distress
-
Pregnancy or lactation (because no safety information is available).