Table 1 Strengths and limitations of radiography and magnetic resonance imaging

Strengths

• Inexpensive

• Widely available

• Short examination time

• Sensitive to change

• Specific because it directly shows cartilage

• Positioning is not an issue, since cartilage can be directly visualized

• Treats the joint as a whole organ

Limitations

• Not sensitive to change: minimal progression is not identifiable, so large patient sample size and lengthy studies are required

• Not specific: meniscal extrusion and damage may account for joint space narrowing

• Change in positioning is problematic in multicenter and long-term studies

• Does not show other important structures that account for pain in osteoarthritis

• Expensive

• Limited availability

• Long examination time

• Requires expert knowledge (that is, input of radiologist is essential) for choice of appropriate pulse sequences and imaging protocol

• Difficulties with repositioning

• Challenges of imaging obese patients who do not fit the coil

• Images with identical pulse sequences may not be obtained across all sites in multicenter magnetic resonance imaging studies