Additional contents from webparts:The particular properties of these three agents are detailed in the table below:
|Mean bubble size||2-8 µm||3.0-4.5 µm||1.1 – 2.5 µm|
|Shell composition||Predominantly phospholipid||Human albumin||Predominantly phospholipid|
|Most frequent side effects in clinical trials||Headache; nausea; chest pain; injection site reaction; parasthesia; vasodilation||Headache; nausea and / or vomiting; warm sensation or flushing; dizziness||Headache; flushing; back pain|
|Manufacturer||Bracco||GE Healthcare||Bristol-Myers Squibb|
The most widely used UCA in Europe is Sonovue, whilst Optison and Luminity (marketed in America as Definity) are more frequently used in the US. These contrast agents are administered intravenously and can be given as a bolus or as a continuous infusion. The contrast agents come in their separate constituents and Sonovue®, for example, is ‘made up’ by mixing saline with a dry powder to make a suspension of the contrast agent. ‘Making up’ the contrast agent when needed takes no more than 2-3 minutes and the steps are illustrated in the diagram below.
Method of preparation of ultrasound contrast
Saline is drawn into a syringe (top left) – both provided in the pack – and then injected into a vial (top right) containing the dry powder constituting the shell and also containing the inner gas.
The vial is then agitated / shaken for 30-60s (bottom left) to mix the contents effectively and the contrast suspension is then ready to be drawn up into a syringe (bottom right) ready for intravenous injection.
A continuous infusion can also be used to produce a steady concentration of contrast within the heart and Bracco, manufacturers of Sonovue®, offer a specific Vueject® pump designed to administer an intravenous infusion. The syringe of contrast agent is placed in the pump, as shown below, and this syringe is then constantly rotated to agitate the mixture (to prevent settling / separation of contents). The infusion line is then connected to a cannula and is ready for administration. The rate at which the contrast is infused obviously determines how long the contrast lasts before it is used up.