Radiography: pelvis

• Attention to detail in radiographing the pelvis is important, as high standards of positioning are vital for accurate radiological assessment.
• A good supply of the appropriate positioning aids is needed.
• It is particularly important that the patient is highly compliant; GA or heavy sedation with analgesia is usually required.
• The image should include the whole pelvis, the proximal femora, and the soft tissues surrounding the femora, as any muscle wastage should be noted.
• The film should be checked for correct positioning, exposure and processing and should be free from movement blur and artifact.
• The anatomical marker must be clearly visible, along with the patient's identification, the date, and the name of the hospital or practice.

Print off the Owner factsheetXrays and ultrasound - why they help my vet  Xray and Ultrasound  to give to your clients.

• Advanced 3D modeling techniques have been used to describe sexual differences in pelvic parameters - this information may be of use when interpreting 2D images.

Uses

• Fractures of the pelvis.
• Fractures   Limb fracture  of the proximal femur     .
• Dislocation of the coxofemoral joint.
• Neoplastic disease.
• Hip dysplasia.
• Investigation of hindlimb lameness.
• Follow-up to assess progression of healing or disease.

Advantages

• Non-invasive.
• Straightforward.

Disadvantages

• Radiography provides 2D images only. Some cases may benefit from 3D imaging.
• Other imaging modalities such at CT or MRI may be necessary to further evaluate some patients.

Technical problems

• Poor attention to positioning may lead to non-diagnostic radiographs.

Time required

Preparation

• Dependent upon method of chemical restraint: GA or sedation.
• Collapsed animals may be radiographed without chemical restraint, with judicious use of small sandbags (avoiding obscuring the area of interest) and foam wedges - but not with tying tapes.

Procedure

• 10-15 min, or longer, dependent upon skill of radiographer.

The patient should be left in position while the film is processed, if possible, so that any inaccuracies in the projection can be corrected from the original position.

Decision taking

Criteria for choosing test

• Can you make the diagnosis without it?
• Can it tell you what you need to know?
• Will your management be affected by the radiological findings?

Choosing the right projections

Ventrodorsal

• The standard and most useful projection     .
• Enables detection of most fractures and assessment of the coxofemoral joints.

The frog-legged ventrodorsal projection may be useful to demonstrate some femoral neck and head fractures and is usually more comfortable for the rabbit if there is pain and extension of the hips.

Lateral pelvis

• Shows direction of displacement in hip dislocation.
• Necessary for assessment of fracture displacement.
• Not suitable for assessing the femoral head and neck.

Lateral of one hip

• Important for assessing fractures     or neoplasia involving the femoral head and neck.

Risk assessment

• Perform a clinical examination before administration of chemical restraint.
• If pathology such as a fracture is suspected on clinical examination, be careful not to over-manipulate the site and worsen the injury.