Ordering MRI of the Knee and Ankle Simultaneously
Yes, it is technically possible to order and perform MRI scans of both the knee and ankle at the same time, though this is not standard practice and requires specific clinical justification for each anatomical region.
Technical Feasibility
MRI technology supports simultaneous imaging of multiple body regions:
- Bilateral imaging capability has been demonstrated for knee MRI using dual-coil-array configurations, allowing both knees to be scanned simultaneously with comparable image quality and scan times similar to single-knee acquisitions 1
- Multiple anatomical regions can be imaged in sequence during a single MRI session, though this extends total scan time 2
Clinical Appropriateness Considerations
The decision to order imaging of both regions should be driven by specific clinical indications for each anatomical area, not convenience:
When Imaging Both Regions May Be Justified
- Polytrauma scenarios where significant injury affects multiple lower extremity joints 3
- Suspected knee dislocation where comprehensive evaluation of ligamentous, vascular, and soft tissue injury is needed, and concomitant ankle pathology is clinically suspected 4
- Specific clinical findings at both the knee and ankle that independently meet criteria for advanced imaging 3
Important Caveats
Avoid unnecessary imaging. The ACR Appropriateness Criteria emphasize that in ankle trauma with inversion injury or fracture, knee radiographs should not be performed owing to low yield 3. This principle extends to MRI—imaging should be targeted to the symptomatic region unless there is specific clinical concern for pathology at both sites.
MRI overutilization is a documented problem. Studies show that 87% of pre-referral foot and ankle MRI scans obtained before specialist evaluation were unnecessary, with specialists ordering MRI in only 5.9% of cases 5. This underscores the importance of appropriate clinical indication rather than screening multiple regions.
Practical Approach
Order imaging based on anatomical regions with specific clinical indications:
- If both knee and ankle have independent clinical findings warranting MRI evaluation, separate orders for "MRI knee" and "MRI ankle" can be placed
- The imaging facility will determine the most efficient scanning protocol (sequential vs. simultaneous if equipment permits)
- Each region requires its own clinical justification and appropriate positioning with specialized coils 2, 6
Initial imaging should typically be radiographs for both knee and ankle trauma before considering MRI, unless there are specific indications for advanced imaging as the initial study 3.