Calcium is helpful for people that form calcium oxalate stones. This is because calcium from the food you eat can bind to oxalate in your gut, reducing the amount of oxalate absorbed by the body. 

Aim to have 3-4 of the following high calcium foods each day, and preferably around mealtimes (700-1200mg calcium per day): 

•  Milk: a third of a pint or 200ml).
• Cheese, including cream cheese: 1oz or 30g.
• Yoghurt: 1 individual size pot.

For healthier options, choose lower fat alternatives

If you use non-dairy alternatives, make sure the product contains 120mg calcium per 100g/ 100ml.

Eating plenty of fruits and vegetables is good for our health, and people that eat plenty of fruits and vegetables appear to have a lower risk of forming kidney stones. Fruits and vegetables may help to make your urine more alkaline (less acidic), and eating a diet that helps to make your urine more alkaline (less acidic) is beneficial because calcium oxalate stones are more likely to form in acidic urine.  

Aim to eat at least 5 portions of fruit and vegetables each day (this does not include potato). 

What is a portion?

• Fruit: what you can hold in your hand (like 2 Satsumas or 1 apple).
• Vegetable: 2-3 heaped tablespoons.
• Salad: the amount to fill a breakfast bowl. 

Eating a lot of animal protein can make your urine acidic, and acidic urine may increase your risk of forming calcium oxalate stones. 

Animal protein foods include: 

• Meat (like beef, lamb, pork, minced meat, ham, burgers, sausages)
• Poultry (like chicken, turkey)
• Fish (like cod, tinned tuna, prawns, fish fingers)
• Eggs and cheese.

Animal protein in cow’s milk and yoghurt has a lower acid load than the foods listed above and does not need to be limited unless eaten in large amounts (exceeding the 4 high calcium foods each day as mentioned earlier). 

Try to limit your portions of animal protein to healthy eating amounts, for example: 

• 60g/ 2oz at a snack meal (cold meat/1 large egg in a sandwich).
• 115g/4oz at a main meal. This amount is about the size of a packet of playing cards.

Plant based proteins do not make the urine acid like animal protein does. Many plant based proteins may help make the urine more alkaline. Here are some ideas to include more plant-based proteins:

• Use lentils and beans as the protein source for meals.
• Reduce meat portion and pad meals out with beans or pulses.
• Include meat free days in the week .

You should limit excessive amounts of high oxalate foods in your diet if you form calcium oxalate stones, especially if you have been found to have high levels of oxalate in your urine. Advising on oxalate is hard because not all foods have been tested. The amount of oxalate in a food can also vary depending on where and when it was grown, and how it has been prepared -for example, boiled potato without skin contains a lot less oxalate than a baked potato (oxalate comes out into the water when boiling). 

The below foods have been found to be high in oxalate, so reducing them in your diet (not eliminating them) may be helpful. 

Very high oxalate (more than 100mg per serving)

• Spinach (raw and cooked)
• Rhubarb
• Rice bran
• Roasted buckwheat groats 

High oxalate (50-100mg per serving)

• Haricot/navy beans (canned)
• Baked beans (canned)
• Almonds
• Cashews
• Bulgar wheat
• Quinoa
• Soy flour
• Brown rice flour
• Baked potato
• Baked sweet potato
• Beetroot
• Dark Chocolate
• Miso (soup) 

Nutritional information taken from the Harvard School of Public Health and University of Chicago How To Eat A Low Oxalate Diet | Kidney Stone Program 

If you know you are going to have something high or very high in oxalate, perhaps try and have something high in calcium at the same time. 

High dose vitamin C supplements (1000mg/d or more) have been linked with a higher risk of forming calcium oxalate stones. If you buy vitamins, do not take more than the reference nutrient intake (RNI) or dietary reference value (DRV). The label on the bottle will tell you what percentage of the RNI or DRV the vitamin will give you. Avoid any that will give you more than 100%. 

Overview | Renal and ureteric stones: assessment and management | Guidance | NICE

EAU Guidelines on Urolithiasis - Uroweb

Kidney Stones: Medical Management Guideline - American Urological Association

Not drinking enough can increase your risk of kidney stones. You can try to avoid this by aiming to go through 2.5-3 litres each day (5-6 pints). 

Try to spread drinks evenly through the day. Drink more when it is hot, and during and after exercise. 

Drinks to include: 

• Water (ideal).
• Dilute squash or cordial.
• Carbonated water, carbonated drinks (not sugar sweetened).
• Tea and coffee (limit to 4 mugs day due to caffeine content).
• Fruit tea. 

Drinks to limit: 

• Sugar sweetened drinks.
• Dark carbonated drinks (like cola).
• Large volumes of fruit juices (high fructose content). 

You can get an idea of how big your cups/mugs/glasses by using a measuring jug to measure how much they hold. It may be useful to write this down. 

Am I drinking enough

If you are drinking enough, you will make over 2 litres of urine each day. Your urine urine should be colourless to pale straw coloured (1-3 on the chart below). 

Eating too much salt (or sodium) can increase calcium in your urine, and having higher amounts of calcium in your urine may increase your risk of kidney stones. Too much salt in the diet can also reduce something called citrate in your urine, and low citrate may increase your risk of forming stones. It is recommended that you limit salt in your diet to less than 6g each day (about 1 level teaspoon, or about 6 “pinches” of table salt).

Salt in the diet comes in the form of “added salt” and “hidden salt”. Added salt is what we add at the table or in cooking, and hidden salt is what is found in many shop-bought, processed/ manufactured foods. Around 75% of the salt we eat comes hidden in food, so reading food labels is important when trying to limit the amount we eat. Please see our diet sheet on how to reduce salt in the diet (How to eat less salt | North Bristol NHS Trust). 

Although there may be calcium in your stone, it is important that you have calcium in your diet. If you are not getting enough calcium from your diet, your body will take calcium from your bones. Over time this can weaken your bones. 

Aim to include 3-4 of the following high calcium foods each day (700g-1200g calcium per day): 

• Milk: a third of a pint or 200ml.
• Cheese, including cream cheese: 1oz or 30g.
• Yoghurt: 1 individual size pot.

For healthier options, choose lower fat alternatives.

If you use non-dairy alternatives, make sure they contain 120mg calcium per 100g/100ml. 

Eating plenty of fruits and vegetables is good for our health, and people that eat plenty of fruits and vegetables appear to have lower risk of forming kidney stones.

Aim to eat at least 5 portions of fruit and vegetables each day (this does not include potato). 

What is a portion? 

• Fruit: what you can hold in your hand (for example 2 satsumas or 1 apple).
• Vegetables: 2-3 heaped tablespoons.
• Salad: the amount to fill a breakfast bowl. 

Citrus 

Lemons are high something called citrate, and including lemons in your diet may increase the amount of citrate in your urine. Having good amounts of citrate in your urine is linked with a reduced risk of forming kidney stones. 

Ideas to include more citrus fruit: 

• Try squeezing lemon juice onto food (like Mexican, Thai, fish dishes, and salads).
• Squeeze lemon juice into water to make it more interesting to drink. 

Eating plenty of fruits and vegetables can also increase the amount of citrate in your urine, so it is another reason to reach for at least 5 portions of fruit and vegetables each day. 

Eating too much protein has been linked with an increased risk of forming kidney stones.

Animal proteins include: 

• Meat (like beef, lamb, pork, minced meat, ham, burgers, sausages).
• Poultry (like chicken and turkey).
• Fish (like cod, tinned tuna, prawns, fish fingers).
• Eggs and cheese. 

Try to limit your proteins of animal protein to healthy eating amounts for example: 

• 60g or 2oz at a snack meal (cold meat/1 large egg in a sandwich).
• 115g or 4oz at a main meal. This amount is about the size of a packet of playing cards. 

Animal protein from cow's milk and yoghurt does not need to be limited unless you eat large amounts (more than 4 high calcium foods each day). 

Plant based proteins do not seem to increase the risk of kidney stones. Here are some ideas to include more plant-based proteins: 

• Use lentils and beans as the protein source for meals.
• Reduce meat portion and pad meals out with beans or pulses.
• Include meat free days in the week.

If you buy over the counter vitamins, do not take more than the reference nutrient intake (RNI) or dietary reference value (DRV). The label on the the bottle will will you what percentage of RNI or DRV the vitamin will give you. 

Try to avoid any that give you more than 100%. 

Losing weight if you are overweight may reduce your risk of forming kidney stones. Eating healthily and having smaller portions can help with weight loss. Being more active is also important. 

Keeping good control of your blood sugar levels may help you to reduce your risk of forming kidney stones. Make sure you attend your diabetes appointments at your surgery or hospital. 

Overview | Renal and ureteric stones: assessment and management | Guidance | NICE

EAU Guidelines on Urolithiasis - Uroweb

Kidney Stones: Medical Management Guideline - American Urological Association

Your doctor has requested that you undergo an ultrasound examination with contrast. This examination is usually performed to provide more information about a lesion or blood flow in part of your body.

The procedure involves using an ultrasound machine to view images of the inside of your body. Contrast enhanced ultrasound is like a regular ultrasound, with the addition of the use of small, gas filled bubbles, that are slightly smaller than a cell in the blood. These “microbubbles” are non-toxic and help us to see cavities in the body, large vessels and blood flow to organs. The microbubbles dissolve rapidly and harmlessly in your blood stream.

This type of procedures is safe and easy to perform with no radiation and no risk to the kidneys.

There is a very low risk of minor side effects, including:

• Headache (less than 5%).
• Nausea (0.5%).
• Feeling hot (0.3%).
• Injection site pain (0.3%).

These side effects should settle on the same day as your scan. 

Rarely there have been reactions to the contrast with certain heart diseases such as shunts. We will check your allergies before the procedure to minimise this risk. The doctor may give you medicine if you do have an allergy and we will monitor you after the procedure. 

The only severe side effects have occurred in patients with pulmonary hypertension or serious heart and lungs conditions. You should let us know if you have a severe heart condition, are pregnant or have had a severe allergic reaction in the past.

No special preparation is needed in most cases. However, if you need to starve or fill your bladder, we will inform you of this on your appointment letter.

Yes, you may bring a friend or relative with you. It may not always be possible for them to accompany you into the scanning room but if it is necessary, please do ask and we will try to accommodate your request.

Please go to the Gate 18 reception desk and follow the check-in process in your appointment letter. You will be shown where to wait until a member of staff comes to collect you.

You will be seen by a radiologist (a doctor who specialises in X-rays) or a sonographer (a radiographer who specialises in ultrasound). 

North Bristol NHS Trust is a teaching hospital; there may be a trainee present for some examinations. They will be introduced at the beginning of the examination. If you would prefer them not to be present, please feel free to say to the radiologist or sonographer.

We will tell you if you need to remove any clothes covering the area being examined before your examination. Private cubicles are available if you need to take off your outer garments or put on a hospital gown.

• A member of the team will place an intravenous (IV) catheter for microbubble contrast in one of your arm veins before the scan. A small plastic tube (cannula) may be put into a vein in your arm to allow us to administer during the procedure.
• After this, we will dim the lights so that the images on the screen can be seen more clearly.
• You may be asked to take deep breaths and to hold your breath for a few moments.
• The radiologist or sonographer will move the ultrasound probe over your skin while viewing the images on a screen.
• Ultrasound images will be taken before and after the injection, so that they can be viewed later.
• Occasionally a patient might experience a bitter taste in the mouth or burning or cold sensation in the arm after the injection. The cold sensation is usually the result of the saline (salted water) used to flush the cannula, not the contrast itself.
• After the scan we might ask you to stay in the department for 10-20 minutes to ensure you are well before you leave the department. Before you leave, a member of the team will remove the cannula.

The contrast agent used with ultrasound is approved for use in the UK, Europe and North America.

In the UK, it has been approved for use in the heart and liver lesions. We would like to make you aware however, that it is not specifically approved for examinations of the other organs. This may seem unusual as we will be injecting the same material in the same amount that would be used to examine your heart and liver but scanning over your kidney or other organs. This is known as an “off label use of an approved drug” and is a common practice since often drugs are not specifically approved for every possible use. 

Should you have further questions please feel free to ask the radiologist who, along with the experienced sonographer, will be performing the study.

The process of carrying out a scan usually takes around 20-30 minutes. Unless emergency patients delay you, your total time should be less than an hour.

No. You can drive afterwards and return to work as necessary.

Provided no other investigations are needed, you can eat and drink normally after your scan.

After the scan, we will examine the images further and prepare a report on our findings. This may take some time to reach your referring doctor but is normally less than 14 days. You could ask the radiologist/sonographer how long it might take to get the results. 

This leaflet is based on the NHS England website for Ultrasound scans. Ultrasound scan - NHS (accessed 05.05.2022)

NHS Constitution for England. Information on your rights and responsibilities. NHS Constitution for England - GOV.UK (accessed 05.05.2022)

Guidelines for Professional Ultrasound Practice (2021) Society of Radiographers and British Medical Ultrasound Society, (accessed 05.05.2022)

Sidhu PS, Cantisani V, Dietrich CF, et al (2018) The EFSUMB Guidelines and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound (CEUS) in Non-Hepatic Applications: Update 2017 (Long Version). Ultraschall Med 39:e2-e44.

The EFSUMB Guidelines and Recommendations for the Clinical Practice of Contrast-Enhanced Ultrasound (CEUS) in Non-Hepatic Applications: Update 2017 (Long Version) (accessed 05.05.2022)

S.Weinstein et al.; How to set up a contrast enhanced ultrasound service. Abdom Radiol NY (2018) 43:808-818

Venous vascular malformations are abnormal collections of veins. They are present from before birth, but often not noticeable until much later in life. They grow with the person and may not cause any symptoms at all. 

They most commonly appear as a soft lump and are slightly blue in colour. They may cause pain or be cosmetically disfiguring. These symptoms may worsen after trauma, infection or hormonal changes such as puberty or pregnancy.

Lymphatic malformations are where the lymphatic system (part of the body’s immune system) has failed to form normally in one part of the body and instead forms fluid filled spaces that may occasionally be painful.

Your initial consultation is likely to be with a consultant radiologist, but at North Bristol there are also vascular surgeons, plastic surgeons, and other specialists with experience in vascular malformation management, allowing a multidisciplinary approach to treatment.

Usually, the diagnosis can be made in a clinical examination and by taking a patient history at an outpatient appointment. The area of concern will normally be imaged (scanned) with ultrasound. If the ultrasound does not provide enough information, then an MRI scan may be arranged. 

MRI is particularly useful for assessing larger and deeper malformations, or for providing detail of the anatomy of those malformations near important structures. 

Occasionally imaging cannot provide enough information on its own and then a small piece of tissue (a biopsy) may be needed to analyse the types of cells present in a malformation.

Venous vascular or lymphatic malformations are not dangerous conditions and often require no treatment at all. Treatment is normally only indicated if the malformation causes pain or limits your activity. 

Non-invasive treatments such as compression stockings can be useful for venous vascular malformations and may be tried first before any invasive interventions such as sclerotherapy are discussed.

Sclerotherapy is a treatment for venous vascular or lymphatic malformations. A sclerosant is a powerful chemical that is injected into the vascular or lymphatic spaces within a malformation causing scarring. 

This is performed using imaging guidance to ensure the sclerosant does not affect nearby normal structures. The procedure is performed by a team led by a consultant radiologist. A radiologist is a doctor who has specialist training and experience in the use of imaging to guide treatment.

If sclerotherapy has been proposed for you the consultant radiologist, in agreement with any other doctors involved in your care (consultant surgeon or consultant physician), will have decided that you would be likely to benefit from the treatment. This will have been discussed and agreed with you in clinic. Your opinion will be taken into account and if after discussion with your doctors you do not want the procedure carried out, you can decide against it. 

The procedure uses X-rays and the amount of radiation used is small however if you think you may be pregnant, please inform the Imaging Department before attending the appointment.

You will need to have a blood test a few days before the procedure to check your kidney function, that you are not at increased risk of bleeding, and that it will be safe to proceed. This may be arranged to take place at your GP surgery. 

You can continue taking your normal medication. If you are on any medication which thins the blood (e.g. aspirin, clopidogrel, warfarin, rivaroxaban, dabigatran, apixaban) we ask you to call the Imaging Department using the number on your appointment letter as we may need to adjust your medication before undergoing this procedure.

• You should not eat anything from midnight the night before the procedure. You may drink clear fluids until 7am on the day of the procedure.
• You will arrive at the Imaging Department (Gate 19) and be accompanied into our day case area.
• You may take your normal medication unless instructed otherwise.
• Please inform us if you are allergic to anything.
• The radiologist will discuss the procedure with you. You will be given an opportunity to ask questions. If you want to go ahead with the procedure you will be asked to sign a consent form.
• You will be asked to change into a hospital gown and a small plastic tube (cannula) may be put into your arm.
• Once all the checks have been performed and consent form signed, you will be taken to the procedure room on the trolley. There will be a nurse, radiographer, and a radiologist with you throughout the procedure.
• The radiologist will use an ultrasound machine to look at the vascular malformation to find the correct area to be treated.
• Your skin will be cleaned with an antiseptic solution and covered with sterile drapes.
• The radiologist will then inject local anaesthetic into the area selected, which will briefly sting and then go numb.
• The radiologist will then inject X-ray dye into the malformation to confirm the needle position and that it is safe to inject sclerosant. The sclerosant will then be injected through one or several small needles into the malformation under ultrasound and X-ray guidance. The procedure is likely to take about 30 minutes.
• Once the procedure is complete the needles will be removed, and the radiologist will apply a dressing if necessary. If the malformation is in a limb, the limb may be bandaged, and you may be asked to wear a compression garment for a period of 1 week.

• You will be taken back to the day case area, so that nursing staff may monitor you closely.
• If you are in pain, please tell the nursing staff so you can be given appropriate painkillers.
• You will be required to stay in our day case area for 4 hours.
• You will be able to eat and drink as normal.
• If everything is satisfactory, you will be free to go home.

Sclerotherapy is usually a safe procedure. Potential complications include:

• n In the first 24 hours following sclerotherapy, the area is likely to be very swollen. Painkillers will be administered as necessary to keep the pain under control. The pain will resolve within a few days, but it may take several weeks for the swelling to settle completely.
• You may notice your urine turn red the first time you urinate after the procedure. This is entirely normal after sclerotherapy and should not cause you any concern.
• You may experience a fever during the first 12 hours after the procedure, though this will resolve without further treatment.
• The one serious risk associated with sclerotherapy is if the sclerosant spreads beyond the malformation and causes damage to nearby normal tissues. This is a rare complication but can cause permanent damage to the affected tissues. One example could be damage to the overlying skin which may ulcerate and cause scarring of the area. Other structures that could be affected depend whereabouts in the body the malformation is, but could include muscle or nerve damage which may be permanent.

If you experience any symptoms you are concerned about, please contact the Imaging Department directly on the number on your appointment letter or alternatively contact your GP or the Emergency Department. 

You should check your travel insurance if you wish to travel within 4 weeks of this procedure.

The amount of sclerotherapy that can be performed at a single treatment session is limited by the local pain and swelling caused. Whether or not multiple sessions are required depends in part on the size of the malformation, but most people with a vascular malformation require multiple sessions. This may be 2, 3, or 4 for a successful outcome. 

Because it is rare for a patient to be completely cured of a vascular malformation, the malformation may again start to cause symptoms in the future and further treatment session(s) may be required at that time.

Patients with a vascular malformation suitable for sclerotherapy are likely to have an improved quality of life in the majority of cases following a series of sclerotherapy treatment sessions. However, it would be very unusual for the patient to be completely cured. It is almost never possible to eliminate the malformation completely using sclerotherapy. 

Again, if you experience any symptoms you are concerned about, please contact the Imaging Department directly on the number on your appointment letter or alternatively contact your GP or the Emergency Department. 

Finally, we hope this information is helpful. If you have any questions either before or after the procedure the staff in the Imaging department will be happy to answer them.

Cabrera J et al (2003) “Treatment of venous malformations with sclerosant in microfoam form”. Archives of Dermatology, 139, 1409-1416 

Donnelly LF et al (1999) “Combined sonographic and fluoroscopic guidance a modified technique for percutaneous sclerosis of low flow vascular malformations”. American Journal of Roentgenology, 173, 655-657 

Ogita S et al (1994) “OK-432 therapy in 64 patients with lymphangioma”. Journal of Pediatric Surgery, 29, 784- 785 

Website available at: Birthmark Support Group [accessed April 2024]

The amount of radiation involved is small. We can assure you that all efforts to minimise radiation are taken. The benefit to you of having the scan to help with a diagnosis will outweigh any risk from the radiation. Your referring doctor will have considered this carefully before asking us to carry out this examination.

Each type of nuclear medicine examination will have a different preparation. Please read your appointment letter carefully as it will specify what the preparation for your particular scan will be.

• The isotope is usually injected into a vein in your arm but for some examinations it may be swallowed or breathed in the form of a gas. This depends on the type of examination being performed.
• The injection of the radioactive substance is similar to having a blood sample taken. You will not feel any ill effects, drowsiness or sickness, and it will not affect your ability to drive a car.
• For some examinations scanning begins immediately and for others there is a delay between the injection and the images. Some examinations have both immediate and delayed scans.
• If there is a long period of delay between the injection and the scan you will be able to leave the department during this interval. This can be confirmed with the radiographer or technologist who will be looking after you.
• During the scan you will have to keep still for periods of time, ranging from a few minutes, up to an hour.
• You can normally leave your clothes on but we may ask you to remove any metallic objects.

Some of the radioactive substances are excreted in breast milk. Therefore, if you are breastfeeding it is important to contact us as soon as you receive your appointment letter. We will give you simple guidance about what to do beforehand and written instructions on the day of attendance. For the majority of scans there will be no need to stop feeding your child.

Please ring us as soon as you receive your appointment letter if you are having renal dialysis. It may be necessary to alter the days you have your treatment to fit in with the scan.

For most nuclear medicine examinations, we ask that you avoid prolonged close contact with children or pregnant women for some time following your scan.

If your scan requires specific instructions, these will be discussed with you on the date of the appointment. If you are the sole carer of small children, it may be advisable to ask someone to help you on the day of your examination. If this is difficult, please ring the department for advice. 

Your pets will not be affected.

You will be able to bring someone with you to the appointment (e.g., relative, friend or carer), provided they are not pregnant and are over 18 years old. Due to the radiation used for our scans, we may ask you to attend alone for some parts of the procedure. 

If you would like more information about having someone with you during your procedure, please call us in advance so that we can advise you further.

The radioactive injection required for this examination is ordered especially for you. If you are not able to attend, please let us know at least the day before your appointment to ensure that we have enough notice to cancel the injection or to allocate it to a different patient on our waiting list.

For some nuclear medicine procedures, we may need to get a list of your medications to ensure that we obtain the best results possible, as some medications affect our scans. If the procedure you are scheduled for requires us to check your medication, this will be detailed in your appointment letter.

If you are or if you think you may be pregnant, please contact us before your appointment date by phoning 0117 414 1814. Becoming pregnant soon after a nuclear medicine scan is not a cause for concern.

When you leave the department after your scan you will be given information about the type of radioactive substance you have received and specific precautions to observe following the procedure. You should keep this with you following the scan in case you need to see a doctor or dentist for any reason in the time specified on the information sheet. You should show them the information before you receive any treatment.

We usually recommend you drink plenty of fluids and empty your bladder regularly as this will help your body to clear the radioactivity.

You may also need to avoid prolonged contact with children under 18 and anyone who is pregnant. If you are breastfeeding specific instructions will be given to you.

For most scans, it is advisable that you do not have a blood or urine test following the radioactive injection.

If your work involves close contact with other people and/or you are involved in radiosensitive work, we may advise you not to return to work until the day following your investigation.

It is very unlikely that you will feel any side effects after the scan, but if you do think that you have, please let the Nuclear Medicine department know.

It is perfectly safe for you to travel abroad after your scan, but many airports and sea ports are now equipped with very sensitive detectors. Therefore, the very small amount of radiation left in your body could set off a detector as you pass through security. 

If you intend to travel abroad within the days following your appointment, please let the Nuclear Medicine department know, and additional documentation can be provided to you to facilitate your travel plans. 

The results will not be available at the time of your scan. The images will be examined in detail by a specialist doctor, who will issue a report. This will be sent to the doctor that referred you for the scan. You will hear about the results and any further care plans from their clinic. 

British Nuclear Medicine Society

Information for Patients and Carers.

British Nuclear Medicine Society

Public Health England

Information on Ionising Radiation Exposure of the UK Population.

Welcome to GOV.UK

Royal College of Radiologists

Information for Patients.

Homepage | The Royal College of Radiologists

NHS Constitution

Information on your rights and responsibilities

NHS Constitution for England - GOV.UK