27/08/2025
🧠 MRI Brain Pathologies in the Image (Axial FLAIR images mostly)
1. ADEM (Acute Disseminated Encephalomyelitis)
Demyelinating disease, often post-infectious/vaccine.
MRI: Patchy, asymmetric, poorly defined white matter hyperintensities.
2. Adrenoleukodystrophy
Genetic metabolic disorder affecting white matter.
MRI: Symmetric parieto-occipital white matter lesions, sometimes with enhancing rim.
3. CADASIL (Cerebral Autosomal Dominant Arteriopathy with Subcortical Infarcts and Leukoencephalopathy)
Genetic small-vessel disease.
MRI: White matter lesions in anterior temporal poles and external capsule.
4. CNS Lymphoma
Primary brain tumor.
MRI: Hyperintense lesion, often deep periventricular, may restrict diffusion, homogeneous enhancement.
5. High-Grade Glioma (e.g., Glioblastoma Multiforme)
Aggressive infiltrating brain tumor.
MRI: Irregular, ring-enhancing mass with necrosis and surrounding edema.
6. HIV Encephalopathy
Viral infection–related brain damage.
MRI: Symmetric, diffuse white matter hyperintensity (non-enhancing).
7. Low-Grade Glioma
Slow-growing brain tumor.
MRI: T2/FLAIR hyperintense, ill-defined, usually non-enhancing.
8. Metastases
Secondary spread of cancer to brain.
MRI: Multiple ring-enhancing lesions with surrounding vasogenic edema.
9. Migraine
Usually normal, but some patients show small punctate white matter hyperintensities, especially in subcortical regions.
10. MS (Multiple Sclerosis): Active
Demyelinating plaques with enhancement.
MRI: Ovoid periventricular lesions, "Dawson’s fingers," with active enhancing plaques.
11. MS: Inactive
Chronic plaques.
MRI: Non-enhancing, T2 hyperintense lesions, hypointense on T1 (“black holes”).
12. MS: Tumefactive
Atypical, large MS lesion that mimics tumor.
MRI: Large >2 cm, mass-like lesion with open-ring enhancement.
13. NMO (Neuromyelitis Optica)
Autoimmune demyelinating disorder (optic nerves + spinal cord mainly).
MRI: Brain lesions can occur, often around ventricles, hypothalamus, area postrema.
14. PRES (Posterior Reversible Encephalopathy Syndrome)
Caused by hypertension, eclampsia, drugs.
MRI: Symmetric vasogenic edema in parieto-occipital regions.
15. PML (Progressive Multifocal Leukoencephalopathy)
JC virus infection in immunocompromised.
MRI: Asymmetric, non-enhancing white matter lesions, without mass effect.
16. Small Vessel Ischemic Disease
Chronic microvascular changes.
MRI: Punctate periventricular and deep white matter hyperintensities.
17. Susac Syndrome
Rare autoimmune microangiopathy (brain, retina, ear).
MRI: Corpus callosum "snowball" lesions.
18. Toxic Leukoencephalopathy
Caused by toxins/chemotherapy.
MRI: Symmetric confluent white matter hyperintensities.
19. Vascular Ischemia (Stroke)
Infarction due to blocked artery.
MRI: Cortical or subcortical restricted diffusion (acute), hyperintensity in vascular territory.
🔑 Key Differentiating Points
MS → Ovoid periventricular lesions, Dawson’s fingers, active vs inactive plaques.
ADEM → Asymmetric, post-infectious, pediatric/young.
CADASIL → Anterior temporal/external capsule lesions.
PRES → Posterior symmetric parieto-occipital vasogenic edema.
PML → Asymmetric non-enhancing lesions in immunocompromised.
Gliomas vs Metastases → Glioma = infiltrative, single; Metastases = multiple, ring-enhancing.
HIV encephalopathy → Diffuse symmetric white matter change.
