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A contrast echocardiogram is a heart ultrasound performed with a tiny injection of ultrasound contrast — either microbubble contrast to sharpen views of the left ventricle, or agitated saline to detect a hole in the heart (patent foramen ovale) with a bubble study. Delivered in Marylebone by BSE-accredited consultant cardiac sonographers, from £495, with a written report within 24 hours. No GP referral required.
Most patients do not need contrast — start with our standard echocardiogram overview, or learn about stress echocardiography and transoesophageal echocardiography (TOE).
A standard transthoracic echocardiogram produces excellent images in most patients, but in a minority the view of the left ventricle is limited by body habitus, lung disease, or post-surgical chest anatomy. In other cases, the clinical question is specifically whether a tiny channel exists between the right and left sides of the heart. Both situations are solved by adding a small intravenous injection of ultrasound contrast during the scan.
Two quite different contrast protocols are used, and they answer different clinical questions. Microbubble contrast agents (for example SonoVue) make the blood in the left ventricle highly reflective, sharpening the endocardial border so that ejection fraction, wall motion, and apical structures can be seen with diagnostic clarity. Agitated saline — a bubble study — introduces a bolus of small air bubbles into the right heart, and the cardiologist watches whether any bubbles appear on the left side, which would indicate a right-to-left shunt such as a patent foramen ovale.
Contrast echocardiography at Sonoworld is performed by BSE-accredited consultant cardiac sonographers with specific training in cannulation and ultrasound contrast administration, supported by a second clinician for patient monitoring during the scan.
Contrast is added to an echocardiogram for one of two reasons: to rescue an otherwise non-diagnostic scan in a patient whose chest anatomy limits image quality, or to answer a specific question about intracardiac or pulmonary shunts. Most standard cardiac questions do not need contrast.
| Clinical Question | Protocol |
|---|---|
| Poor image quality on plain TTE | Microbubble contrast for LV opacification — NICE DG5 recommends this when two or more segments are not adequately visualised |
| Accurate ejection fraction in poor windows | Microbubble contrast — particularly valuable in obese, COPD, and post-cardiac-surgery patients |
| Suspected left ventricular thrombus | Microbubble contrast — after anterior myocardial infarction, in dilated cardiomyopathy, or in atrial fibrillation with apical dyskinesis |
| Cryptogenic stroke or TIA | Agitated saline bubble study — to identify a patent foramen ovale as a possible embolic route |
| Migraine with aura | Agitated saline bubble study — association with PFO is recognised, though closure is selective |
| Decompression illness in divers | Agitated saline bubble study — PFO increases risk of nitrogen bubble passage to the arterial circulation |
| Suspected apical hypertrophic cardiomyopathy | Microbubble contrast — apical thickening is very easy to miss without contrast enhancement |
| Suspected pulmonary AV malformation | Agitated saline bubble study — late crossover (after 4–5 beats) suggests a pulmonary rather than cardiac shunt |
Certain patients have chest walls that make plain ultrasound views of the heart technically limited — notably those with obesity, significant COPD, previous heart or lung surgery, chest deformities, or large breast tissue. When two or more left ventricular segments are not adequately visualised, NICE diagnostic guidance DG5 recommends the addition of microbubble contrast rather than repeating the scan or proceeding to cardiac MRI.
After an anterior myocardial infarction, the apex of the left ventricle is at risk of forming a thrombus in the dyskinetic wall. Detecting or ruling out this clot is essential because it changes anticoagulation decisions. Contrast dramatically improves the sensitivity and specificity of that assessment compared with plain imaging.
In younger patients with an unexplained stroke or TIA, a patent foramen ovale can provide a route for a clot from the leg veins to reach the brain. An agitated saline bubble study — often with a Valsalva manoeuvre to provoke shunting — is the first-line non-invasive screening test. Positive studies are usually followed by a transoesophageal echocardiogram to characterise the defect before any closure decision.
A PFO is more common in divers who have experienced unexplained decompression illness, because nitrogen bubbles forming during ascent can cross the septum and enter the arterial circulation. A bubble study is the standard screening test and informs decisions about diving practice, equipment, and fitness to dive.
"Contrast echo" is an umbrella term for two quite different studies. They use different contrast agents, they answer different clinical questions, and they are not interchangeable. Your referring clinician or our triage team will decide which protocol you need before the appointment is confirmed — and some patients need both during the same visit.
A licensed ultrasound contrast agent (such as SonoVue) is injected slowly through an intravenous cannula during the echocardiogram. The microbubbles fill the left ventricular cavity and produce a bright, clearly defined endocardial border. The result is a diagnostic-quality assessment of ejection fraction, wall motion, and apical anatomy in patients whose plain scan was limited.
Sterile saline is mixed with a small volume of air, agitated between two syringes to produce a cloud of tiny bubbles, and injected rapidly through a cannula. The bubbles immediately fill the right side of the heart. The cardiologist watches for any bubbles appearing on the left side, typically while you perform a Valsalva manoeuvre to provoke a right-to-left shunt.
At the time of booking, our clinical team asks about the reason for the scan. A patient wanting to investigate whether they have a hole in the heart after a stroke needs a bubble study. A patient whose previous echo was reported as "suboptimal image quality" needs microbubble LV opacification. A patient who has had a large heart attack and is being investigated for possible apical clot needs microbubble contrast. Very occasionally we run both protocols in the same appointment if two questions need answering — this is decided case-by-case.
Contrast echocardiography is not a replacement for any other cardiac test — it is an enhancement of standard ultrasound when the plain scan cannot answer the question. The table below summarises where contrast echo fits among the other cardiac imaging modalities.
| Test | What It Shows | IV Access | Best For |
|---|---|---|---|
| Contrast echocardiogram | Enhanced LV imaging or shunt detection using ultrasound contrast | IV cannula | Poor acoustic windows, apical thrombus, PFO/ASD detection |
| Standard echocardiogram (TTE) | Heart structure, valves, ejection fraction at rest | None | First-line for almost all cardiac imaging |
| Stress echocardiogram | Heart function under physical or pharmacological stress | None (IV for dobutamine) | Inducible ischaemia, exertional symptoms, valve disease under load |
| Transoesophageal echo (TOE) | High-resolution valve, left atrial, and aortic imaging from inside the oesophagus | IV cannula + sedation | Endocarditis, prosthetic valves, pre-cardioversion LAA assessment, PFO characterisation |
| Cardiac MRI | Detailed heart anatomy, perfusion, and scar quantification | IV contrast (gadolinium) | Cardiomyopathy workup, myocardial viability, complex congenital |
Note that contrast is sometimes added to stress echo or TOE when image quality is limited — these are combined protocols rather than separate tests. For a full side-by-side of echo modalities, read our echocardiogram comparison guide, or call 020 3633 4902 if you are unsure which test matches your symptoms.
Preparation for a contrast echo is only slightly more involved than for a standard echocardiogram. You do not need to fast, you can take your usual medications, and you can drive home afterwards. The one additional element is that a small intravenous cannula is placed in your arm or hand for the contrast injection.
No fasting is required. Eat and drink normally. A small snack an hour or two before the appointment is fine. Being well hydrated makes cannulation easier, so a glass of water on arrival is encouraged.
Take all regular medications as normal. There is no need to stop any medication — including blood thinners such as warfarin, apixaban, rivaroxaban, dabigatran, or edoxaban. Antiplatelet agents such as aspirin and clopidogrel are also continued.
Wear comfortable clothing that is easy to remove from the upper body. You will undress from the waist up, lie on a couch, and a sleeve can be rolled up for the cannula. Avoid lotions and oils on the chest because they prevent ECG electrodes from sticking.
Let the clinical team know at the time of booking if you have ever had an allergic reaction to an ultrasound contrast agent, to any medicine, or to latex. Serious reactions are rare but the team needs to know in advance so the right precautions are in place.
You can eat, drink, drive, return to work, and resume all normal activities immediately after the appointment. There is no sedation, no post-procedure restriction, and no monitoring period beyond the scan itself. You may have a very small plaster over the cannula site — you can remove it after an hour. Mild bruising on the hand or forearm for a day or two is common and settles without treatment.
The appointment takes 45 to 60 minutes from arrival to discharge. The scan itself combines a standard echocardiogram with a short additional period during which the contrast is administered and imaged. Here is what to expect at each stage.
We confirm your clinical history, medications, allergies, and the reason for the scan. The sonographer explains which contrast protocol is being used — microbubble, bubble study, or both — and you sign a consent form.
A small intravenous cannula is placed in a vein in your arm or the back of your hand. This is used only for the contrast injection — nothing else goes through it. You may feel a brief scratch; most patients describe cannulation as a momentary discomfort only.
A complete transthoracic echocardiogram is performed first — imaging the chambers, valves, and function of your heart from the chest wall. This establishes the baseline and identifies whether contrast is needed for all the views or only some.
For microbubble LVO, the contrast is injected slowly through the cannula while the sonographer images the left ventricle in multiple views. For a bubble study, agitated saline is pushed through the cannula as a rapid bolus, often during a Valsalva manoeuvre (bearing down as if blowing into a closed straw) to provoke any right-to-left shunt.
The cannula is removed, a small plaster is applied, and the sonographer shares initial observations with you in plain English. This is not a formal report but gives you an immediate sense of the findings and any next steps.
Your formal written report — including measurements, contrast findings, Doppler data, and clinical interpretation — is typically delivered within 24 hours. With your consent we send a copy directly to your GP, cardiologist, or referring clinician.
Ultrasound contrast agents have an excellent safety record. Licensed microbubble agents such as SonoVue have been in routine clinical use for over twenty years, and published series consistently report serious adverse event rates below 1 in 10,000 studies — a profile considerably better than iodinated CT contrast or gadolinium-based MRI contrast. Agitated saline is ordinary saline with a small volume of air and has been used for bubble studies for decades.
Crucially, ultrasound contrast contains no iodine, no gadolinium, and no radiation. It is cleared from the body through normal breathing within a few minutes. It is safe in patients with any level of kidney function, can be used in patients with shellfish or iodine allergies, and does not interact with medications.
Common (not serious): brief warm sensation, metallic taste, or mild headache that resolves within a few minutes. Mild bruising at the cannula site. Uncommon: transient nausea, flushing, or lightheadedness. Rare (well under 1 in 10,000): allergic reactions to microbubble contrast, which can range from mild rash to anaphylactoid reactions. The clinical team is trained in resuscitation and emergency medication is immediately available throughout the appointment.
Most patients are suitable for contrast echo. At triage, we will ask about:
Many of these are relative rather than absolute. Each case is reviewed individually before booking is confirmed.
Chest pain at rest, sudden severe breathlessness, new one-sided weakness or facial droop, sudden speech difficulty, or any symptoms suggestive of stroke or heart attack need urgent hospital assessment. Do not book a private contrast echo — call 999 or go to your nearest A&E. A contrast echo is a planned investigation for stable clinical questions, not a test for acute events.
Appointments are available Monday to Saturday. A member of the clinical team will call you to confirm which protocol (microbubble LVO or agitated saline bubble study) is appropriate for your clinical question before the booking is finalised.
Choose your preferred date and time on our secure booking page. A member of the clinical team will call you to confirm which protocol is suitable, answer questions about preparation, and arrange any final details.
Price includes full echocardiogram, IV cannulation, ultrasound contrast agent, verbal feedback, and a written report within 24 hours. Insurance patients: please bring your authorisation code. See the full echocardiogram cost breakdown.
Insurance patients are welcome. Sonoworld is recognised by most major insurers including Bupa, AXA Health, Aviva, and Vitality. If you are unsure whether you need a contrast echo, a standard transthoracic echocardiogram is almost always the right first step — contrast can be added later if the plain scan is technically limited or the clinical question requires it.
A standard echocardiogram uses an ultrasound probe on the chest wall to image the heart without any injections. A contrast echo adds a small intravenous injection — either a licensed microbubble contrast agent to sharpen the view of the left ventricle, or agitated saline to detect a right-to-left shunt. The probe and scanning technique are the same; contrast is used only when the clinical question requires the extra information.
Both are called "contrast echo" but they answer different questions. A bubble study uses agitated saline — ordinary saline mixed with a small amount of air — to look for a patent foramen ovale or other right-to-left shunt. A microbubble contrast echo uses a licensed medicine such as SonoVue to sharpen the view of the left ventricle when the plain scan has poor image quality. Some patients need both during the same appointment; most need only one. Our clinical team decides which protocol is appropriate before booking.
No — ultrasound contrast is completely different from CT or MRI contrast, and it has a better safety profile than either. Microbubble agents such as SonoVue contain tiny bubbles of sulphur hexafluoride gas and are cleared from the body through normal breathing within a few minutes. There is no iodine, no gadolinium, no radiation, and no kidney risk. Published safety data consistently report serious adverse event rates below 1 in 10,000 studies. Patients with shellfish allergies, iodine allergies, poor kidney function, and those who cannot have MRI contrast can all safely receive ultrasound contrast.
Yes — a small intravenous cannula is placed in your arm or the back of your hand to administer the contrast. Most patients describe cannulation as a brief scratch, similar to a routine blood test. The contrast injection itself is painless. Some patients notice a very brief warm sensation or metallic taste when the microbubble contrast is given; this passes within a few minutes.
No. Unlike stress echocardiography or transoesophageal echo, contrast echo requires no fasting and no change to your routine. Eat and drink normally. Being well hydrated makes cannulation easier, so a glass of water when you arrive is encouraged.
Yes. Ultrasound contrast agents are not filtered by the kidneys — they are cleared through normal breathing. This makes contrast echo safe at any level of kidney function, and it is often the test of choice in patients who cannot receive CT or MRI contrast for renal reasons.
A Valsalva manoeuvre means bearing down and holding, as if trying to blow through a closed straw. This briefly raises the pressure in the right side of the heart, which can open a patent foramen ovale and allow bubbles to cross from right to left — making a small shunt that would otherwise be undetectable visible on the scan. The sonographer will coach you through it. Most patients find it easy after a practice attempt or two.
Yes. No sedation is used and the contrast wears off within minutes. You can drive, return to work, and resume all normal activities immediately after the appointment. Mild bruising around the cannula site for a day or two is common and does not require any treatment.
Microbubble contrast agents are not licensed for use in pregnancy and we would not perform a microbubble contrast echo on a pregnant patient unless there was a very specific clinical indication reviewed by a cardiologist. Agitated saline bubble studies are considered on an individual basis. Please let the clinical team know at the time of booking if you are pregnant or might be pregnant — a standard echocardiogram without contrast is safe at any stage of pregnancy and is usually the right first step.
Verbal feedback is given immediately after the scan. A formal written report — including all echocardiographic measurements, contrast findings, and clinical interpretation — is typically issued within 24 hours. With your consent, a copy is sent directly to your GP, cardiologist, neurologist, or referring clinician.
A positive bubble study means a right-to-left shunt has been detected — usually a patent foramen ovale. The next step depends on why the test was requested. In patients investigated for cryptogenic stroke, a positive bubble study typically leads to a transoesophageal echocardiogram to characterise the defect in detail, followed by a specialist discussion about whether percutaneous closure would be appropriate. The written report will explain the finding and recommend next steps.
Yes. Appointments can be cancelled or rescheduled up to 24 hours before the appointment time without charge. Cancellations made within 24 hours may be subject to a fee. Call 020 3633 4902 or email info@sonoworld.co.uk to make changes.
29 Weymouth Street
London W1G 7DB
Nearest stations: Regent's Park (Bakerloo) · Great Portland Street (Circle, H&C, Metropolitan) · Baker Street (Jubilee, Bakerloo, Metropolitan)
Open in Google MapsContrast echo appointments run as scheduled clinic sessions — call for the next available slot.
Contrast echo enhances a standard transthoracic study. These are the other echo modalities available at Sonoworld.
Non-invasive first-line heart ultrasound.
Heart function under exercise or dobutamine.
High-resolution imaging from inside the oesophagus.
Heart rhythm & electrical conduction. 5–10 min.
Condition explainers and follow-up reading from our cardiovascular patient library.
What a PFO is, how it's detected with a bubble study, and when closure is considered.
What EF means, why contrast matters when image quality is limited, and how to read your number.
How heart failure is diagnosed, why accurate ejection fraction matters, and what treatment changes with it.
Why contrast echo is used to check for apical thrombus after an anterior MI, and what the findings mean.
How unexplained stroke is investigated, and where bubble studies fit in the diagnostic pathway.
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