The right imaging test depends on your symptoms, clinical examination and suspected condition. Not every patient needs an advanced scan. The aim is to choose the investigation that provides the information needed to make the right treatment decision.
Types of diagnostic imaging
1. X-ray
X-rays are usually the first imaging investigation for many orthopaedic conditions. They provide excellent information about bones, joints and alignment.
Commonly used for:
- Arthritis and joint degeneration
- Fractures and dislocations
- Joint alignment
- Bone deformities
- Hip and knee assessment
- Evaluation of joint replacements
- Pre-operative planning
Weight-bearing X-rays can be particularly important for assessing knee arthritis, hip problems and lower-limb alignment.
2. MRI scan
MRI provides detailed images of soft tissues as well as bones and does not use ionising radiation. It is particularly useful for diagnosing:
- ACL and PCL injuries
- Meniscus tears
- Rotator cuff tears
- Shoulder labral injuries
- Cartilage injuries
- Tendon and ligament injuries
- Muscle injuries
- Stress and occult fractures
- Certain causes of persistent joint pain
MRI is especially valuable in sports injuries and shoulder disorders.
3. CT scan
CT provides highly detailed images of bones and is particularly useful when precise information about bone anatomy is required. CT may be recommended for:
- Complex fractures
- Joint fractures
- Bone defects
- Deformities
- Complex hip, knee and shoulder problems
- Assessment of previous implants
- Detailed pre-operative planning
In selected cases, 3D CT reconstruction can provide additional information for surgical planning.
4. Ultrasound
Musculoskeletal ultrasound is a radiation-free investigation that can assess muscles, tendons and other superficial soft tissues. It can be useful for:
- Rotator cuff disorders
- Biceps tendon problems
- Tendinitis
- Bursitis
- Muscle injuries
- Tendon tears
- Joint effusions
One advantage of ultrasound is that certain structures can be assessed dynamically while the joint is moving.
Bone health and metabolic imaging
5. DEXA / DXA scan
A DEXA (dual-energy X-ray absorptiometry) scan is primarily used to measure bone mineral density and assess bone strength. DEXA may be recommended for:
- Suspected osteoporosis
- Previous fragility fracture
- Assessment of fracture risk
- Postmenopausal bone health
- Age-related bone loss
- Monitoring response to osteoporosis treatment
- Patients at increased risk of bone loss
Strong bones are important for preventing fractures and achieving good outcomes after certain orthopaedic procedures. Identifying low bone density allows appropriate bone-health assessment and treatment to be considered.
Nuclear medicine imaging
6. Bone scan
A bone scan is a nuclear medicine investigation that evaluates activity within the bones. A small amount of a radioactive tracer is injected into a vein. Areas of increased or abnormal bone activity can then be identified using a specialised gamma camera.
A bone scan may be useful in selected situations such as:
- Occult or stress fractures
- Unexplained bone pain
- Certain bone infections
- Evaluation of some bone tumours
- Assessment of multiple areas of the skeleton
- Selected cases of painful joint replacement
A bone scan can sometimes identify an abnormal area even when a conventional X-ray is inconclusive.
7. Nuclear medicine scan
Nuclear medicine imaging uses small amounts of radioactive tracers to evaluate the function and activity of tissues rather than simply their structure. Depending on the clinical question, different nuclear medicine scans may be used to assess:
- Bone metabolism
- Bone infection
- Certain painful or loose joint replacements
- Stress injuries
- Certain tumours
- Other causes of unexplained bone or joint symptoms
Specialised techniques such as SPECT or SPECT/CT may sometimes provide both functional and anatomical information.
Imaging is only one part of your diagnosis
An imaging report should always be interpreted alongside your symptoms and clinical examination. An abnormality on an MRI or other scan does not necessarily mean that it is the cause of your pain, and not every abnormal finding requires surgery.
Symptoms + clinical examination + appropriate imaging = better diagnosis and treatment.
