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Skull Base investigations

Your consultant may recommend that you have some tests done in order to help correctly diagnose what is causing your symptoms.

You will receive detailed information about any tests and investigations you need. You may require one or more of the investigations explained below.

The professional conducting the investigation will make sure you are aware of the procedure and have had the risks and benefits involved with any investigations explained to you. Sometimes, tests need to be repeated to ensure the correct diagnosis is made.

The following tests and investigations are carried out during Outpatient clinics:

Blood tests

Blood tests are usually done to assess your general state of heath, checking things like whether you are anaemic and how organs such as your liver and kidneys are working.

Chest X-ray

A chest X-ray will be performed to assess your general fitness and to check your heart and lungs.

Hearing test

Hearing assessments are done by audiologists. The test involves you pressing a button every time you hear a tone. A wide range of tones are played through headphones. The quietest tones you can hear are recorded and from this any hearing loss, its type and nature are determined. This will enable your consultant to diagnose your condition.

The appointment can last up to an hour. It is recommended to bring hearing aids or mould if you already use them. 

Ear examination

Your consultant may choose to examine your ear if necessary. The examination can be done using an ‘otoscope’, which is like a pen torch. It has its own magnification, which gives a good view of the tympanic membrane. The technique involves gently holding the pinna and pulling it up and backwards, which helps to straighten the ear canal. This also helps with the inspection of the ear.


Nasendoscopy is a small procedure to examine your nose and sinuses. It is a thin telescope with a light at the end that is inserted through your nostrils. This may be uncomfortable but will only last a few minutes. This can make you sneeze.

The endoscopic examination looks into all areas of the nose, showing the exact location of any narrowing, bony deformities, polyps and the source of any concerns. This helps with the development of a treatment plan.


Sometimes, in order to reach a diagnosis, the consultant may need to examine a tissue sample under a microscope. To do this, it is necessary to remove a small piece of the ulcer or lump. This can be done as a minor procedure under local or general anaesthetic. Your consultant will be able to discuss the options and risks.

Ultrasound scan

Ultrasound scans use sound waves to build up a picture of the inside of your body. The procedure is painless, easy and fast. You will be asked to lie flat on your back on the examining table. A gel is put onto the skin in the area to be scanned and a probe is passed over the area.

For some scans you may be asked to avoid eating or drinking for up to 12 hours prior to your appointment. The scan can last for 10 to 20 minutes, in order to perform a full examination.

Ultrasound may be used to guide a biopsy or fine needle aspiration if it is needed for diagnosis. 

Computerised tomography (CT) scan

A CT scanner is shaped like a doughnut. You will be required to lie on a couch that will move you through the machine. This test uses a rotating X-ray beam to create a series of pictures of the body from many different angles.

Sometimes you will be given an injection of dye called ‘contrast’ which allows particular areas to be seen more clearly. Please inform your doctor before the scan if you are diabetic or suffer from any kidney problems. The injection may make you feel hot all over for a few minutes.

Before the scan it is important to tell your doctor or the person performing the scan if you are allergic to iodine or have asthma.

A CT scan is painless and takes between 10 and 30 minutes. You will be able to go home when the scan is over and will be able to drive home.

CT scans offer a detailed view of many types of tissues such as organs or bones.

Magnetic resonance imaging (MRI) scan

MRI scans use magnetism to build up a picture of the organs inside the body. It is completely painless, rather noisy and takes approximately 30 to 45 minutes.

Before the scan, you may be injected with a special dye to help make the pictures clearer. You should tell the doctor if you have a pacemaker or any metal inside your body, including joint replacements, surgical clips, screws, or implants as this may mean you cannot have this type of scan.

During the scan you will be asked to remain as still as possible, in a confined space. In a small number of cases patient can find this claustrophobic. If this is a concern for you, then please discuss this with your consultant.

MRI during pregnancy is avoided where possible due to the risks involved.

Positron emission tomography (PET) scan

PET uses low-dose radioactive drug glucose (a type of sugar) that is injected into your arm to measure the activity of cells in different parts of the body. It may help find out if a tumour is cancerous (malignant) or non-cancerous (benign). They can also find out if it has spread to other parts of the body.

PET scans can also be used to examine any lumps that remain after treatment to see if they are scar tissue or whether cancerous cells are still present. In this way, the PET scanner can make 3D images that show where the radioactive drug went to in your body.

On the day of your scan you will be advised not to eat or drink anything for six hours prior to your appointment (except water). You will be given an injection into a vein that will feel similar to a blood test. There are no side effects from the injection and it will not make you feel any different. After receiving the injection you will need to rest and remain lying down for one hour while the injection is absorbed into your body. Once the radioactive tracer has been absorbed into your body you will be ready for the scan.

In the scanning room, you will be asked to lie on your back on the scanning bed. The bed will move through the ring of the scanner and collect images for between 30 to 60 minutes, depending on the type of scan. Because the radioactivity is short lived, your radiation exposure is low. The substance amount is so small that it does not affect the normal processes of the body.

It is strongly recommend that you don’t have close contact with any pregnant women or young children for eight hours following the scan. If you are pregnant or breast feeding, you should inform the staff as the baby or foetus may be exposed to radiation. 

Dental assessment

You may be advised to have a dental assessment and treatment before having surgery or radiotherapy (X-ray treatment that uses high radiation energy to damage or kill cancer cells). This is because radiotherapy can adversely affect the teeth, gums and bones supporting the teeth and saliva which protects the teeth and moistens the mouth.

It is important to check whether your teeth are in their best possible condition before receiving radiotherapy.

If you have any questions please ask your consultant, oncologist or a nurse. It may help to write down questions as you think of them and bring them to your appointment.

It is important to bring the list of all your current medication with you to all your follow up clinic appointments.

It may also help to bring someone with you when you attend your outpatient appointments.

Last reviewed: 31 October 2022