HRCT of temporal bone :
An HRCT scan of the temporal bone is an imaging test that can help visualize the internal structures of the temporal bone. The temporal bone is the part of the skull that surrounds the ear. It also includes the inner ear, middle ear and outer ear bone.
HRCT scan is an advanced form of CT scan. Thinner slices are prepared in HRCT as compared to CT scan. While the slice size in CT scan is 1.25 mm, it can be up to 0.625 mm in HRCT. These slices are converted into images with the help of a computer algorithm (system of rules for solving problems).
This is done in two notices:
• Coronal (view obtained from the front),
HRCT scan is an advanced form of CT scan . Let us tell you, in HRCT, thinner slices are prepared than in CT scan. While in CT scan the slice size is 1.25 mm, in HRCT it can be up to 0.625 mm. With the help of a computer algorithm (system of rules for solving problems), these slices are converted into images. This scan can be done in two positions: coronal (view obtained from the front) and axial (view obtained from below).
Contrast dye is usually not needed during the test , but it may be used in some situations. It is used to get more clear and detailed images. HRCT scan can help to look for normal variations and pathological conditions such as congenital disease or temporal bone infection .
Why is temporal bone HRCT done?
The HRCT temporal bone test is done to check for cochlear implants or to diagnose the following conditions that affect the temporal bone:
Deafness
trauma
tumor
infection
HRCT temporal bone may be suggested if the doctor notices the following symptoms or signs:
Hearing loss (Read more - Home remedies for hearing loss )
Headache
ear ache
ear discharge
facial nerve weakness (weakness of the nerve that affects taste, speech, and hearing)
tinnitus (ringing in the ears)
fever
Vomiting
Vertigo (feeling like the environment is spinning)
ataxia (degenerative nervous system disorder characterized by loss of control over body movements)
Who should not have temporal bone HRCT?
Generally, there are no contraindications to this scan. However, this scan should be avoided in the following situations:
Pregnancy (especially in the first trimester, as the radiation used in this test can cause developmental defects in the baby)
young people
claustrophobic _
contrast dye allergy
Preparation before temporal bone HRCT
If non-contrast dye HRCT is performed, no special preparation is required, but if contrast dye is to be used, it is recommended not to eat or drink for at least 4-6 hours before the test. Are being given.
Inform the doctor if you are pregnant or expect to become pregnant.
Leave jewellery, hair accessories, glasses and dentures at home before going in for the test, as these will not be allowed in the scanning room. All of these things can affect the test results.
When you go to the hospital, you may also be given a gown to wear before the test. Hearing aids, dentures and piercings may also be asked to be removed before going in for the scan.
Note when contrast dye HRCT is performed:
Also inform the doctor if you have diabetes or kidney disease , as the use of contrast dye may require special precautions.
Inform the doctor if you have allergies or are taking any medications .
Just before the test, the radiographer will insert a plastic tube called a cannula into a vein in your arm , through which the dye will be injected into the body.
How is a temporal bone HRCT scan performed?
The procedure for performing an HRCT scan of the temporal bone is as follows:
First you will be asked to lie down on a scanning table, which will slide inside the machine once you are comfortable.
The table will move in and out of the machine several times during the scan.
The radiographer may ask you to lie still during the scan, as any movement can distort the photos.
If contrast dye is to be used, it will be injected through a vein in your arm and then images of the temporal bone will be taken.
Once the test is done, the radiographer will help you get off the scanning table.
This scan usually takes half an hour.
How will it feel during temporal bone HRCT?
There is no pain during this test , but you may feel a little uncomfortable due to continuous lying down. If contrast dye is used, you may have a slight metallic taste in your mouth and a feeling of warmth in your body. Also, you may feel the urge to urinate. These are all side effects of the contrast dye, which gradually heals on their own. Also during the scan, you may hear buzzing, clicking and whistling sounds from the machine.
What do temporal bone HRCT results mean?
An HRCT scan can help diagnose the following conditions:
infection :
Mastoiditis (inflammation of the mastoid bone, located behind the ear)
cholesteatoma (abnormal growth of skin behind the eardrum)
External malignant otitis (pseudomonas infection in the temporal bone)
otitis media and inner ear infections
Neuritis (inflammation of the peripheral nervous system)
Break:
Acoustic neuroma (noncancerous tumor that usually grows slowly)
facial nerve tumor
the strokes :
fracture
congenital conditions
Hearing loss due to infection, trauma, congenital condition or tumor, any cause
Risks and benefits of HRCT of the temporal bone? - Temporal Bone HRCT risks and benefits?
Advantages of HRCT Scan:
High-resolution images are obtained in HRCT
details the microscopic structures inside the auditory canal (the narrow passageway from the outer ear to the eardrum)
It is painless, precise and non-invasive
Can simultaneously take pictures of different tissues such as bone, blood vessels and soft tissues
This test can also be done if you have ever had an implant (although some metal objects may also show up in the result).
Radiation is no longer present in the body after the test
Risks of HRCT :
This procedure is generally safe. However, in pregnant women, this test can cause harm to the fetus.
Contrast dye may cause allergic reactions in some people
Children are more sensitive to radiation and hence this test is less recommended for them.
What happens after HRCT of the temporal bone?
You can go home and return to your regular activities after the scan is complete. Apart from this, you can also take diet normally. However, if contrast dye is used, you need to watch for side effects like itching , difficulty in breathing , swelling or rash for some time. If this happens, consult a doctor immediately. Apart from this, there may be mild pain or swelling at the injection site.
Other tests that can be done with a Temporal Bone HRCT?
Other tests with temporal bone HRCT may vary depending on the situation. For example, some conditions of the middle ear may be better diagnosed by otoscopy. To diagnose acoustic neuroma , tests such as MRI , audiogram , auditory brainstem response, and electronystagmography may be done.