Is contrast necessary for a knee Magnetic Resonance Imaging (MRI)?

From the Guidelines

Contrast is not routinely necessary for knee MRI examinations, as most knee MRI scans can be performed without contrast to adequately visualize standard structures of interest, including ligaments, menisci, cartilage, bones, and muscles. According to the American College of Radiology Appropriateness Criteria 1, MRI knee without IV contrast is usually appropriate in patients with chronic knee pain when initial radiographs are normal or demonstrate a joint effusion. However, contrast may be recommended in specific situations, such as evaluating for infection, inflammatory arthritis, tumors, synovitis, or following surgery when scar tissue needs to be distinguished from recurrent pathology 1.

The decision to use contrast should be made by the radiologist and referring physician based on the specific clinical question being addressed. Contrast works by enhancing areas with increased vascularity or where the blood-tissue barrier is compromised, which can help identify certain pathologies that might not be apparent on standard imaging. Patients should be aware that contrast administration involves an intravenous injection and carries a small risk of allergic reaction or other complications, particularly in those with kidney problems.

Some studies suggest that contrast-enhanced MRI can be useful in diagnosing specific conditions, such as Hoffa’s disease, deep infrapatellar bursitis, patellofemoral friction syndrome, and adhesive capsulitis 1. However, the use of contrast should be tailored to the individual patient's needs and the specific clinical question being addressed.

In acute knee trauma, MRI can diagnose patterns and severity of bone marrow contusions, predict associated soft-tissue injuries, and facilitate diagnosis of anterolateral ligament injuries and posterolateral corner injuries 1. However, the use of contrast in these situations should be determined on a case-by-case basis, taking into account the patient's clinical presentation and the specific diagnostic question being addressed.

Key points to consider when deciding whether to use contrast in knee MRI examinations include:

• The specific clinical question being addressed
• The patient's clinical presentation and medical history
• The potential benefits and risks of contrast administration
• The availability of alternative diagnostic modalities
• The radiologist's and referring physician's expertise and preferences.

Overall, the decision to use contrast in knee MRI examinations should be made on a case-by-case basis, taking into account the individual patient's needs and the specific clinical question being addressed.

From the Research

Contrast or No Contrast for Knee MRI

The decision to use contrast or not for a knee Magnetic Resonance Imaging (MRI) depends on various factors, including the patient's kidney function and the specific condition being evaluated.

• Kidney Function: Studies have shown that the use of gadolinium-based contrast agents (GBCAs) in patients with severe chronic kidney disease (CKD) or acute kidney injury (AKI) can increase the risk of nephrogenic systemic fibrosis (NSF) 2, 3. However, the risk of NSF is negligible with group II GBCAs, even in patients with advanced CKD or those on dialysis 4.
• Non-Contrast MRI Techniques: Recent studies have explored the use of non-contrast MRI techniques, such as quantitative double-echo in steady-state (qDESS) and fluid-attenuated inversion recovery (FLAIR), for assessing synovitis in the knee 5, 6. These techniques have shown promise in visualizing synovial inflammation without the need for contrast agents.
• Specific Conditions: The use of contrast agents may be necessary for certain conditions, such as evaluating the severity of synovitis or assessing disease activity in rheumatic disorders 6. However, non-contrast techniques may be sufficient for other conditions, such as evaluating joint effusion or Hoffa-synovitis 6.
• Radiologist Preference: The choice of contrast or non-contrast MRI may also depend on the radiologist's preference and experience with different techniques 5, 6.

Key Findings

• Non-contrast MRI techniques, such as qDESS and FLAIR, can visualize synovial inflammation without the need for contrast agents 5, 6.
• Group II GBCAs have a negligible risk of NSF, even in patients with advanced CKD or those on dialysis 4.
• The use of contrast agents may be necessary for certain conditions, such as evaluating the severity of synovitis or assessing disease activity in rheumatic disorders 6.