Table 1 Advantages and limitations of musculoskeletal ultrasound (MSUS) compared to magnetic resonance imaging (MRI) and conventional radiology in children with juvenile idiopathic arthritis
Imaging modality | Advantages | Limitations |
|---|---|---|
MSUS | Lack of exposure to ionizing radiation Rapidity of performance Ease of repeatability High patient acceptability Demonstration of soft tissue inflammation Direct visualization of cartilage Early detection of bone erosions Ability to scan multiple joints in a single session Support in guidance of procedures (e.g. intra- articular corticosteroid injections) Relatively inexpensive | Difficulties in carrying out in case of severe joint limitation Relatively small field of view Inability to assess the whole joint space Acoustic shadowing from overlying bones Limited value in the assessment of axial skeleton and temporomadibular joints Dependency on the properties and sensitivity of the ultrasound equipment Need of continuous practice after appropriate training Reliability, standardization and validation in children under investigation |
MRI | Lack of exposure to ionizing radiation Multiplanar tomographical imaging Ability to assess the whole joint space Demonstration of soft tissue inflammation Direct visualization of cartilage Early detection of bone erosions Visualization of bone marrow oedema High tissue contrast Suitable for assessment of axial skeleton and temporomadibular joints | Intravenous contrast agent often required Possible allergic reaction to contrast agents General anesthesia required in younger children Long examination time Evaluation limited to one target joint Reliability, standardization and validation in children under investigation High cost Variable availability worldwide |
Conventional radiology | Rapidity of performance Applicability to all joints Demonstration of joint space narrowing, disturbances of bone growth and maturation Detection of bone erosions Validated scoring methods in children Suitable for longitudinal evaluation of damage progression Low cost Widespread availability | Exposure to ionizing radiations Inability to directly visualize cartilage and soft tissue inflammation Late detection of bone erosions and joint space narrowing Projectional superimposition |