sulfur hexafluoride at a glance
Medicine class
Ultrasound contrast medium
Purpose
Diagnostic imaging only; it does not treat the condition being investigated
Administration
Given by trained staff into a vein in adults or through a bladder catheter for licensed paediatric urinary-tract imaging
After administration
Medical observation is required because serious allergic reactions can occur shortly afterwards
What is sulfur hexafluoride used for?
Licensed uses apply when ultrasound without contrast has not answered the clinical question.
In adults, improving views of the heart chambers and the inner border of the left ventricle during echocardiography.
In adults, improving Doppler assessment of cerebral, carotid and peripheral arteries and the portal vein.
In adults, displaying blood flow within liver and breast lesions to support more specific characterisation.
In children from birth to 18 years, intravesical ultrasound of the urinary tract to detect vesicoureteral reflux.
Some NHS services use sulfur hexafluoride microbubbles for sentinel lymph-node mapping in breast cancer; this is not covered by the selected licence.
How does sulfur hexafluoride work?
The gas is enclosed in microscopic bubbles. Their gas–liquid surfaces strongly reflect ultrasound waves, increasing contrast between blood or urinary fluid and surrounding tissues. After intravenous use, dissolved gas is rapidly removed through the lungs in exhaled air.
How to take sulfur hexafluoride
This is administered during an imaging procedure rather than taken at home. Trained staff prepare the microbubble dispersion immediately before use and give it through a peripheral vein in adults, or through a urinary catheter for licensed paediatric reflux imaging.
Tell staff about previous reactions to sulfur hexafluoride, polyethylene glycol or injectable contrast agents.
Remain available for the required observation period after administration.
Report new symptoms immediately rather than waiting for the examination to finish.
sulfur hexafluoride side effects
Common or expected effects
- Headache, reported uncommonly in clinical trials but among the most frequently reported effects
- Injection-site reaction, reported uncommonly
- Nausea, reported uncommonly
Get urgent medical advice
- Breathing difficulty, marked swelling, widespread redness or rash, collapse or loss of consciousness suggesting severe hypersensitivity
- Severe dizziness or faintness associated with low blood pressure or a vasovagal reaction
- New chest pain or other symptoms suggesting reduced blood flow to the heart
sulfur hexafluoride in pregnancy
There are no clinical data from exposed pregnancies. Although animal studies did not indicate reproductive harm, use during pregnancy is preferably avoided as a precaution. Tell the imaging team if you are pregnant or may be pregnant.
sulfur hexafluoride while breastfeeding
It is unknown whether sulfur hexafluoride enters human milk. The product information states that breastfeeding can resume two to three hours after administration because the gas is rapidly cleared in exhaled air. Confirm the practical plan with the imaging team.
sulfur hexafluoride interactions
Formal interaction studies have not been performed. The following situations are specifically relevant to safe use.
Dobutamine
Do not combine with sulfur hexafluoride in patients with cardiovascular instability where dobutamine is contraindicated.
Beta blockers
If anaphylaxis occurs, beta blockers may reduce the response to adrenaline and contribute to unwanted hypertension or bradycardia.
Common questions about sulfur hexafluoride
Answers are fully visible for fast scanning and source review.
Why is sulfur hexafluoride used only when an ordinary ultrasound is inconclusive?
It adds reflected ultrasound signals from blood or urinary fluid, which may reveal structures or flow that were not clear on the original scan.
Is sulfur hexafluoride an iodine-based contrast agent?
No. It is a gas-filled microbubble ultrasound contrast agent and is not an iodine-based X-ray contrast medium.
How is sulfur hexafluoride administered?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.