How should I analyze a brain MRI report?

How to Analyze a Brain MRI Report

A brain MRI report should be systematically analyzed by examining three core components: the technical parameters, the findings section with standardized terminology, and the radiological conclusion that directly addresses the clinical question. 1

Essential Components of Every MRI Report

1. Technical Parameters Section

Review the MRI technique description first, which must include: 1

• Anatomical area covered (brain, spinal cord, optic nerve)
• Field strength (minimum 1.5T for diagnostic quality)
• Slice thickness (ideally 3mm or less)
• Contrast agent details (type, dose of gadolinium if used)
• Sequence types performed (T1, T2, FLAIR, DWI, etc.)

These technical details are critical for comparing examinations performed at different time points or imaging centers. 1

2. Findings Section - The Core Analysis

The findings section should provide a comprehensive, systematic description using standardized terminology. Look for: 1

Lesion Characteristics:

• Number of lesions on T2-weighted and gadolinium-enhancing T1 sequences 1
• Topography (location: periventricular, juxtacortical, infratentorial, spinal cord) 1
• Size and shape with reference to disease-specific characteristics 1
• Qualitative assessment of T2 and T1 lesion load 1

Additional Key Elements:

• Brain atrophy assessment (semiquantitative visual evaluation) 1
• Positive and negative imaging features that support or argue against specific diagnoses 1
• Active lesions (gadolinium-enhancing, new, or substantially enlarged T2-hyperintense lesions on follow-up scans) 1
• Incidental findings clearly labeled as clinically relevant or irrelevant 1

3. Conclusion Section - Clinical Integration

The conclusion must briefly communicate the radiological interpretation as it relates to the specific clinical problem. 1

Key elements include: 1

• Identification of typical or atypical lesion patterns for suspected diagnoses
• Differential diagnosis considerations
• Fulfillment of diagnostic criteria (e.g., dissemination in space and time for MS)
• Evidence of disease activity or progression

Clinical Context Determines Interpretation Priority

For Suspected Multiple Sclerosis or Demyelinating Disease

Brain MRI is the investigation of choice and powerful predictor of clinical course. 2 When analyzing reports: 1

• Count periventricular, juxtacortical, infratentorial, and spinal cord lesions separately
• Note that four or more MRI lesions at presentation predicts higher progression rates to clinically definite MS 2
• Spinal cord imaging is mandatory with spinal symptoms and helpful when brain findings are equivocal 1
• The spinal cord rarely shows incidental MS-like abnormalities, even in older patients 1

For Acute Neurological Deficits or Altered Mental Status

MRI serves as the second-line test when CT is unrevealing, with superior sensitivity for small infarcts, encephalitis, and posterior fossa lesions. 3, 4

Priority findings to identify: 3, 4

• Small ischemic infarcts (70% of missed stroke diagnoses present with altered mental status) 3, 4
• Posterior fossa abnormalities poorly visualized on CT 3, 4
• Subtle subarachnoid hemorrhage (MRI has 95% sensitivity) 3, 4
• Encephalitis patterns (should be imaged within 24-48 hours of suspected diagnosis) 3, 4

For Subacute or Chronic Head Trauma

MRI is more sensitive than CT for subtle findings and should be the primary modality when rapid detection of acute hemorrhage is not the focus. 1

Look for: 1

• Focal encephalomalacia at inferior frontal or anterior temporal lobes (chronic contusion sequelae)
• Small white matter lesions (microbleeds from traumatic axonal injury)
• Findings that explain persistent cognitive or neurologic deficits

Critical Pitfalls to Avoid

Technical Limitations

MRI can miss extensive cerebral calcifications that are obvious on CT. 5 Even T2 gradient-echo sequences have limited benefit for detecting calcifications. 5 If clinical suspicion exists for:

• Pseudohypoparathyroidism
• Fahr disease
• Other calcification disorders

Request CT imaging regardless of MRI findings. 5

Incidental Findings

Four percent of research brain MRIs reveal potentially clinically significant incidental findings. 6 The most common abnormalities requiring follow-up are: 6

• Vascular (43%)
• Neoplastic (21%)
• Congenital (15%)

Nonradiologists flag less than 1% of abnormalities that neuroradiologists deem concerning. 6 This underscores the importance of formal neuroradiologist interpretation rather than relying on preliminary reads.

Context-Dependent Yield

The diagnostic yield of MRI varies dramatically by clinical presentation: 1, 4

• Very low yield in new-onset psychosis without neurologic deficits 1
• Very low yield in new-onset delirium without focal deficits or recent falls 1, 4
• High yield (76% management changes) in acute disorders of consciousness 3, 4

Structured Reporting Advantages

Structured reporting improves communication efficiency and clinical decision-making compared to conventional narrative reports. 1 Structured formats: 1

• Present information in standardized, organized fields
• Integrate clinical data (symptom onset, disability level, treatment)
• Facilitate research and comparative analysis
• Improve diagnostic confidence

When to Request Additional Imaging

Add contrast-enhanced sequences when the clinical picture suggests: 1

• Autoimmune disorders (multiple sclerosis, neuropsychiatric lupus)
• Intracranial infection or mass
• Inflammatory lesions
• Vascular pathologies requiring characterization

Consider spinal cord MRI when: 1

• Brain findings are equivocal (cerebrovascular disease, autoimmune disorders, age-related changes)
• Brain lesions are suggestive but don't fulfill diagnostic criteria
• Spinal cord symptoms are present at onset