Contrast for Bone MRI in Fracture Evaluation
For simple fractures without red flags, MRI without contrast is sufficient and preferred, as it effectively detects bone marrow edema to determine fracture acuity and distinguishes benign from pathologic fractures. 1, 2
When Contrast is NOT Needed
Non-contrast MRI alone is appropriate for:
- Acute fracture evaluation - Bone marrow edema on non-contrast sequences (T1-weighted and STIR/fat-suppressed T2) reliably determines fracture acuity and age 1, 3
- Osteoporotic compression fractures - Normal marrow preservation on T1-weighted images is consistent with benign osteoporotic fractures 4
- Occult or stress fractures - MRI without contrast has high sensitivity for detecting radiographically occult fractures through marrow signal changes 3, 5
- Routine fracture assessment - Non-contrast sequences provide excellent visualization of fracture lines, bone contusions, and associated soft tissue injuries 5, 6
The Society of Skeletal Radiology explicitly states that contrast is not recommended for routine trauma or fracture imaging 6.
When to ADD Contrast (MRI Without AND With IV Contrast)
Contrast enhancement is indicated when specific red flags suggest complications:
Infection Concerns
- Suspected osteomyelitis or epidural abscess - Contrast with fat suppression is invaluable for identifying abscesses and distinguishing abscess from phlegmon 3
- Fever, immunosuppression, or IV drug use - These red flags warrant contrast-enhanced imaging 1, 3
Malignancy Concerns
- History of cancer or unexplained weight loss - Contrast helps delineate tumor extent, epidural involvement, and distinguish metastatic from benign fractures 1, 2
- Pathologic fracture features - Pedicle involvement, posterior element extension, convex posterior vertebral body border, or soft tissue mass require contrast evaluation 2, 4
- Multiple level involvement with atypical features - Though multiple fractures can be osteoporotic, contrast helps when malignancy is suspected 4
Complex Clinical Scenarios
- Post-operative complications - Contrast is helpful in complex post-surgical cases 6
- Inflammatory spondyloarthropathy - Suspected inflammatory processes benefit from contrast 1, 3
Critical Decision Algorithm
Step 1: Assess for Red Flags 1, 2
- History of cancer
- Unexplained weight loss
- Fever or signs of infection
- Immunosuppression
- IV drug use
- Pain preceding trauma (suggests pathologic fracture)
Step 2: Choose Imaging Protocol
- Red flags present → MRI without AND with IV contrast 1, 3
- No red flags → MRI without IV contrast 1, 3
Step 3: Evaluate Initial Non-Contrast Images
- If non-contrast MRI is indeterminate for malignancy or infection, add contrast as a subsequent study rather than repeating the entire exam 1
Important Caveats and Pitfalls
Never order contrast-only MRI - Contrast sequences must be correlated with standard non-contrast sequences; ordering contrast alone is inappropriate 1, 3
Radiographs have limitations - Vertebral fractures on plain films are difficult to date without prior comparison studies; MRI is needed to determine acuity 3, 1
CT cannot replace MRI for fracture characterization - While CT provides excellent bone detail for surgical planning, it cannot assess bone marrow edema or reliably distinguish benign from malignant fractures 1, 2
Osteoporotic fractures can occur in cancer patients - The presence of malignancy history alone doesn't confirm pathologic etiology; imaging differentiation is essential 2, 7
Soft tissue injuries - While contrast may improve soft tissue visualization in complex trauma, non-contrast MRI adequately demonstrates most tendon, ligament, and soft tissue injuries associated with fractures 8, 5
Pregnancy considerations - For suspected hip or pelvic fractures in pregnant patients, MRI without contrast is the initial test of choice due to high complication risk and avoidance of ionizing radiation 3