canis - Articles
Radiography: skull (basic)
Introduction
- Radiography of the skull requires general anesthesia. This is the only way to obtain accurate projections.
- A grid is necessary when patient thickness >10 cm.
- The different skull shapes are treated similarly for the basic projections.
- Specialised projections such as tympanic bullae require adaptation of technique based on the shape of the skull.
- Radiography of the skull for fractures may be of questionable value as the presence of a fracture is considerably less significant than the presence of neurological signs. It may, however, in some cases, be of value in explaining the reason for the signs when trauma is a possibility but has not been observed.
- When using non-screen film for intraoral radiography the increase in exposure required is immense. It is therefore necessary to ensure that the equipment is adequate, that the finger is not removed from the exposure button before completion of the exposure, and, most importantly, that staff do not re-enter the room before termination of the long exposure.
- The objective is to produce well-positioned radiographs which are correctly exposed and developed, free from movement blur and free from artefact.
- The anatomical marker must be clearly visible.
- If manual processing is used then the patient’s identification, the date, and the name of the hospital or practice must also be visible.
Uses
- Fracture
. - Bony neoplasia
. - Soft tissue neoplasia Nasal cavity: neoplasia , eg nasal tumors
. - Temporomandibular joint disease Temporomandibular joint: disease - overview
. - Hydrocephalus Hydrocephalus
. - Nasal foreign body
. - Ear disease
and tympanic bulla involvement Otitis media 
. - Infectious rhinitis Rhinitis.
Alternative techniques
- In patients with neurological signs there is often nothing to be gained by X-raying the skull as it is the brain which needs to be imaged.
- Magnetic Resonance Imaging (MRI) is the modality of choice for most brain imaging.
- CT is available for brain imaging but artifacts from dense skull bone can obscure lesions, and soft tissue contrast with CT is inferior to MRI.
- Ultrasonography can be used to image the brain if fontanelles present.
Decision taking
Criteria for choosing test
Is the examination appropriate?- Can you make the diagnosis without it?
- Can it tell you what you need to know? This is often not the case with skull radiography!
- Will your management be affected by the radiological findings?
- Standard projection.
- May show gross fractures, depending on their position.
- May show skull vault shape abnormalities.
- Will give some information about the nasal chambers and frontal sinus, not withstanding the fact that the two sides are overlying each other.
- May show neoplasms involving the bone.
- Standard projection.
- May give information on skull vault shape. May give misinformation or incomplete information on nasal cavity disease because of overlap of mandible and tongue.
- May show gross fractures, depending on their position.
- Good for fractures of the zygomatic arches.
- Good for productive and destructive bone lesions.
- Good for some mandibular fractures and dislocation of the temporomandibular joints.
- Of some use for tympanic bullae and ear canal disease.
- For suspected depressed fractures and for lumps on the skull the best projection is often an oblique, positioned so that the beam passes tangentially across the lesion or area of interest.
- This is preferable to the alternative ventrodorsal open mouth nasal chambers.
- It gives a high resolution image of both sides of the nasal cavity and the radiological appearances can advance the diagnosis of nasal pathology considerably.
- There is a problem in obtaining the non-screen (direct exposure) film necessary for this technique.
- Rostrocaudal frontal sinus view allows detection of frontal sinus fluid, masses, bone production or bone lysis.
Requirements
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Preparation
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Technique
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Aftercare
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.
Outcomes
Subscribe To View
This article is available to subscribers.
Try a free trial today or contact us for more information.