Imaging in lameness Flashcards
List the indications for imaging in orthopaedics
- Acute or chronic lameness
- Skeletal or joint pain
- Fracture confirmation/characterisation
- Swelling centred on bones/joints
- Monitoring/screening for inherited musculoskeletal disease
- Metabolic bone disease
- Evaluation of systemic disease
Describe the steps in the diagnostic process of orthopaedic disease
- DDx list formulated on basis of history and clinical examination (other tests)
- Imaging test performed
- Differential list narrowed based on results
- Further tests (imaging?) performed to narrow new differential list
- Diagnosis and treatment plan
What are the 4 main considerations of the imaging examination
Determine the correct region to image
Select the most appropriate modality/modalities
Perform technically competent examination
Accurately interpret results of study
How can you determine the correct region to image?
Thorough general clinical examination and history
Comprehensive orthopaedic exam
Examination under GA/sedation?
How can you select the most appropriate imaging modality - which modalities are available?
Radiographs initially?
Ultrasound
CT or MRI
Scintigraphy
Which features of the imaging exam will ensure the image is technically competent
- Correct region radiographed
- Well-positioned, reproducible views
- Adequate number/orthogonal (at least 2 views)
- Free from significant artefacts
- Awareness of limitations of radiography
What is geometric distortion and when does it occur?
- Occurs if structure is towards edge of collimated area or not truly parallel to film/detector
- GA or sedation and careful positioning required
- Tight collimation can help
What are the limitations of radiography to be aware of for orthopaedic disease?
Oblique projections can create apparent artefactual lesions
Poor soft tissue contrast resolution
Describe the uses/purpose of serial radiography
Monitor progression of disease
Show diseases radiographically occult in their early stages
Assess dynamic component of disease
Can be useful if diagnosis is uncertain
What are the key points of interpreting radiographs which are fundamental to all modalities?
- Deviation from normal appearance recognised
- Lesion(s) accurately described in systematic fashion
- Pertinent aspects of lesion(s) appreciated from their description
- Formulation of differential diagnoses (with integration of other information from signalment etc)
Describe normal variations seen on radiographs
Normal variations in age, breed, and species need to be considered
What are the 5 Rontgen signs?
Number
Size
Shape (including margins)
Location
Opacity
You should consider that a lesions could also be one of which 3 things?
- Artefact of poor positioning or technique
- Feature/variant of normal anatomy
- Composite shadow of superimposed normal structures
Which areas of bones can be assessed through imaging?
- Alignment, shape, length
- Periosteal reaction/cortical lysis/defects
- Endosteal/medullary changes
- Physes
Which areas of joints can be assessed through imaging?
Swelling/effusion
Subchondral bone
Periarticular changes
What are the possible causes of reduced soft tissue size?
- Atrophy (focal)
- Lameness (chronic)
- Neurogenic
- Fibrosis/scarring - Weight loss (general)
What are the possible causes of increased soft tissue size?
Focal
- Trauma
- Abscess/seroma
- Granuloma
- Neoplasia
Diffuse
- Oedema
- Cellulitis/vasculitis
- Diffuse neoplasia