MRI Findings: Understanding Magnetic Resonance Imaging Results
MRI findings are abnormalities or characteristics detected on magnetic resonance imaging that provide diagnostic information about tissues, organs, and pathological conditions through the visualization of anatomical structures and physiological processes.
Components of MRI Findings
MRI findings are derived from several key imaging sequences and parameters:
- T1-weighted images: Show anatomical detail with fat appearing bright and fluid appearing dark
- T2-weighted images: Show pathology with fluid appearing bright and fat appearing intermediate
- FLAIR (Fluid-Attenuated Inversion Recovery): Suppresses cerebrospinal fluid signal to highlight lesions adjacent to fluid spaces
- DWI (Diffusion-Weighted Imaging): Detects restricted water diffusion, critical for identifying acute stroke and certain infections
- Contrast enhancement: Reveals areas of blood-brain barrier disruption, inflammation, or abnormal vascularity
Common MRI Findings by System
Neurological Findings
- Brain: Infarcts, hemorrhage, tumors, demyelination, atrophy
- Spine: Disc herniation, spinal stenosis, cord compression, syringomyelia
- Specific patterns: "Hockey stick" or "pulvinar" sign in prion diseases like CJD 1
Musculoskeletal Findings
- Joints: Cartilage defects, ligament/tendon tears, bone marrow edema
- Bone: Fractures, osteonecrosis, bone marrow abnormalities
- Soft tissue: Muscle tears, tendinopathy, synovitis 1
Abdominal/Pelvic Findings
- Organs: Masses, inflammation, infection, congenital anomalies
- Vasculature: Aneurysms, stenosis, thrombosis, malformations
Interpretation Framework
The American College of Radiology recommends a systematic approach to analyzing MRI findings 2:
- Verify technical adequacy: Field strength (minimum 1.5T recommended), slice thickness, and sequences performed
- Establish normal anatomy: Identify normal structures as baseline
- Look for asymmetry: Compare bilateral structures
- Assess signal characteristics: Evaluate abnormalities across multiple sequences
- Correlate findings: Compare findings across different planes and sequences
Clinical Applications and Examples
Neurological Applications
- Dementia: MRI can detect specific atrophy patterns and exclude treatable causes 1
- Multiple sclerosis: New or enlarging T2 lesions and gadolinium-enhancing lesions are key markers of disease activity 3
- Rapidly progressive dementia: Diffusion-weighted imaging can differentiate CJD from other causes 1
Spine Imaging
- Back pain: MRI is the modality of choice for assessing spinal cord, nerve roots, thecal sac, and vertebral bodies 1
- Pediatric back pain: MRI can detect spinal dysraphism, syringomyelia, and tethered cord syndrome 1
- Ataxia: MRI can evaluate for cord edema, abnormal signal/enhancement, compression, and vascular lesions 1
Safety Considerations
- Contraindications: Certain implanted devices, pacemakers
- Gadolinium risks: Potential for deposition in tissues with repeated exposure
- Field strength effects: Higher field strengths improve detection capabilities but may increase certain artifacts 4
Common Pitfalls in MRI Interpretation
- Incidental findings: Not all abnormalities are clinically significant
- Artifacts: Motion, metal, chemical shift, and susceptibility artifacts can mimic pathology
- Technical limitations: Some pathologies (e.g., small calcifications) are better visualized with CT than MRI 2
MRI findings must always be interpreted in the context of clinical presentation, as the same finding may have different significance depending on patient symptoms and history.