Head and neck imaging Flashcards
- Which method is least suitable for examining trauma to the orbits? -
USG
- X-ray: semiaxial projection, diagnosis in trauma
- Ultrasound is not commonly used for eye imaging
- CT imaging with contrast is the main method of imaging used: anomalies in the orbit, for example, tumors, expansions and processes behind the eye
- Magnetic resonance imaging gives us the best imaging results for the eye and is best suited for the diagnosis of individual anomalies. Its main disadvantage is worse accessibility.
- Which examinations would you choose for examination of a retrobulbar expansion in an orbit?
- MRI
- Which examination is not suitable for the assessment of the sphenoid sinuses? -
USG
The main imaging modalities for displaying the sinuses are X-ray and CT.
-Semiaxial projection is used: This is a quick and fairly cheap examination.
-Normally, there is air in the cavities which produces a contrast, so it is possible to see a number of pathologies – especially the presence of fluid - which can be either inflammatory fluid or blood.
-This depends on whether the patient has an injury or has inflammation in the sinuses.
This type of imaging is good especially for acute conditions such as acute sinusitis or trauma.
CT
- main method
- performed in low dose settings as there would be sufficient contrast between the air and the bones, and allows us to distinguish between different pathologies, in particular chronic inflammations such as polyps and thickened mucous membranes.
Ultrasound
- an inappropriate method due to the amount of air in the cavity and the bones around them.
MRI
- not usually used for imaging of the sinuses.
- The sphenoid sinuses are best seen on –
A lateral XR projection of the head
- Hydroaeric phenomenon in the sinuses on semiaxial projection of the skull is evident -
In the presence of blood (hemosinus) after trauma
Hydroaeric Phenomenon and this is due to the presence of air and fluid in the cavity.
- What projection is used for the diagnosis of acute sinusitis? –
Semiaxial Projection.
- Which of the following examinations is best for showing facial skeletal trauma?
- A semiaxial XR
- Which examination is best to assess facial skeletal trauma? -
CT
CT is definitely the best choice of imaging for head trauma. It can be performed on large areas and shows fractures very accurately. In addition, 3D reconstructions can also be made. Another important advantage with CT is that we can also observe the brain so we can check for any intracranial hemorrhages. The only disadvantage of the examination is the radiation load, but it is still relatively small for the adults.
- How many projections do we perform when examining C spine using XR?
- 3
C spine is usually X-rayed in three projections – AP, lateral and a specific projection called the Sandberg transoral projection. In this projection the patient opens their mouth so we can see the atlantoaxial region.
Nowadays we only see minor C spine fractures on X-rays. As we discussed earlier for any suspicion of C spine trauma CT is the first choice of imaging.
- The main method for imaging of the salivary glands is -
US
- Ultrasound nicely shows the glands anatomy and shows possible pathologies such as edema, dilatation of the ducts or focuses within the gland.
- If the ultrasound finding is uncertain, CT with contrast can be done. Even though CT is much better for describing the pathology and its surroundings the quality of assessment will not reach the same quality as is achieved with ultrasound.
- MRI can be used to view more extensive and complex expansions of the salivary glands.
In this instance x-rays do not tell us much about glands but may be able to show us large sialolites or in more simple words stones in the glands. A special imaging method for this pathology is called Sialography which is mainly used by ENT to display the ducts and any obstructions via the use of a contrast agent.
- The physiological image of the parotid gland on ultrasound is -
Slightly hyperechogenic, granular and homogeneous
- An inflammatory-activated lymph node on the ultrasound has
– A thicker cortex than in a chronically changed lymph node
Ultrasound can distinguish between reactive inflammatory lymph nodes that have a thick cortex from chronically changed fibrotic lymph nodes. The chronically changed lymph nodes can be seen on the right, they have a large hyperechogenic center and a thin cortex.
Ultrasound can sometimes allow us to investigate and identify malignant tumorous infiltration. The image on the left shows the vascular blood supply of the lymph node
- On which of these examinations you are not able to ses lymph nodes?
- Simple X-ray imaging
CT scans are also very useful in assessing the extent of the process and is better for finding the accurate size of the lymph node and the exact location. CT scans for lymph nodes should always be done with a contrast agent so we can distinguish them from blood vessels
- Which of the following modalities cannot be used to assess the arteries of the neck?
– Native CT
All types of modalities can be used on vessels and the choice depends on the symptoms, severity of patients’ state and availability of given investigations.
- Angiography is a classical X-ray method and for this we put an ionic contrast matter into given vessel. Its main advantage is a possibility of intervention.
- Ultrasound is usually used in patients with chronic problems, for example after brain ischemia etc. We can also visualize the carotid arteries of the neck and also vertebral arteries between vertebrae. The main advantage with ultrasound is the ability to measure velocities in stenotic vessels and no contrast is needed for this.
- CT angiography is widely used today as the new machines work a lot faster. Time plays a key factor when choosing an imaging method especially in emergency situations. As new machines work a lot fast we can use them for viewing the exact filling phase of vessels without causing a delay in treatment. We can easily see closures or stenosis in vessels or any anatomical variants.
- MRI angiography is usually used for brain vessels.
- What is the first-choice method for displaying pathological changes in the thyroid gland? -
US
