Differential diagnosis

From macroscopic MRI to microscopic malady

In addition to the videos and the alphabetic index, some tables with differential diagnosis of MRI findings and the video number (with link) in superscript. They are hopefully helpful – I do not pretend that they are complete.

T2 hyperintens cortex

Disease	Location	Classification	Cause
Stroke 73	Cortex and white matter; focal and unilateral.	Vascular	Cytotoxic edema
Encephalitis6 17	Cortical involvement in e.g. Rasmussen, MOGAD cortical encephalitis and different types of viral encephalitis.	Inflammation and infection	Perivascular infiltration and edema
Astrocytoma 61 and glioblastoma 62	Most common: focal and infiltrative mass in predominantly white matter, may involve cortex. Sometimes: early cortical involvement.	Tumor	Infiltrative glial tumor cells.
Low grade (or long term) epilepsy associated tumor (LEAT). Including ganglioglioma, DNET, MVNT, ANET, PLNTY and isomorphic astrocytoma.	Majority presents as large cortical mass.	Tumor	Both neuronal and glial tumor cells, some types with cysts or microcysts.
Oligodendroglioma 63	Cortex and subcortical, calcified.	Tumor	Tumor cells arranged in honey comb pattern. Chicken wire vascular network. Little surrounding vasogenic edema
Focal cortical dysplasia type II 3	Cortex thickening with blurring of gray white junction and a transmantle sign towards ventricle.	Developmental	Balloon cells and dysmorphic large neurons, originating from the germinal matrix/ventricular zone
Hypoglykemia 56	Parieto-occipital cortex and insula + hippocampus, basal ganglia.	Metabolic	Aspartate increase in extracellular space -> excitatory receptors (NMDA, AMPA) -> cell membrane breakdown and neuronal death
Hepatic encephalopathy 57	Cingulate and insular gyrus, sparing of perirolandic and occipital lobe.	Metabolic	High ammonia -> lower glutamate reuptake in astrocytes and neurons -> increase intracellular glutamine -> Alzheimer type II astrocytes
Ulegyria 11	Parietal and occipital regions, sometimes anterior watershed area. Typically symmetric, may be asymmetric or unilateral. Cortical thinning and subcortical gliosis, especially in the depth of the sulcus. Apex of gyrus spared.	Vascular	Cortical thinning with neuronal loss and astrogliosis
Postictal changes 74	Variable cortical regions, usually unilateral.	Metabolic	Excitotoxic edema
Creutzfeldt-Jakob disease 55	Cortex with perirolandic sparing + caudate, putamen and thalami	Infectious (prion disease)	“Spongiform changes” with vacuolisation of neurons and astrogliosis

T2 hyperintense white matter lesions

Aspecific white matter abnormalities 71	Subcortical and (patchy) periventricular	Normal = one per decade and exponentially after 60 years	lacunar hypoperfusion, axonal loss
Disease	Location	Classification	Cause
Vascular white matter abnormalities 71	Subcortical and (patchy) periventricular	Vascular	lacunar hypoperfusion, axonal loss
Chronic hypertensive encephalopathy 71	Subcortical and (patchy) periventricular + microbleeds mainly in basal ganglia and thalami	Vascular	Lacunar hypoperfusion, axonal loss, leakage of BBB
Multiple sclerosis 39	Juxtacortical, periventricular, corpus callosum, infratentorial	Inflammatory	Demyelination
Posterior reversible encephalopathy syndrome (PRES)46	Subcortical white matter including U-fibers and cortex	Vascular	Vasogenic edema in the extracellular space
Diffuse astrocytoma, IDH-mutant61, 62	Most common: focal and infiltrative mass in predominantly white matter, may involve cortex. Sometimes: early cortical involvement.	Tumor	Infiltrative glial tumor cells
Oligodendroglioma63	Infiltrative mass, cortical and subcortical. Often calcifications and prediliction for frontal lobe	Tumor	Infiltrative glial tumor cells with “fried egg” appearance and chicken wire vascularity
Amyloid microangiopathy68	White matter lesions without typical pattern, prediliction for posterior region + microbleeds at grey-white matter junction and superficial hemosiderosis (+lobar hemorrhage)	Vascular	Extracellular deposition of amyloid in vessel wall leptomeningeal and cortical -> not only hemorrhage but also disruption BBB and inflammation
Neuromyelitis optica (NMO)40	Periependymal periventricular white matter, corpus callosum + Circumventricular organs (periaqueductal gray, hypothalamus, medial thalamus).	Inflammatory	Demyelination, Aquaporin 4 antibodies
Acute Disseminated Encephalomyelitis41	Multifocal in white matter+ asymmetric basal ganglia, thalami.	Inflammatory	Vasogenic (reversible) and cytotoxic edema
Neurofibromatosis58	Subcortical white matter + globus pallidus, other basal ganglia, thalamus and brainstem.	Genetic: OMG (on the antisense DNA of neurofibromin)	FASI, intramyelinic edema
Progressive multifocal leukencephalopathy36	Bilateral, asymmetric. Involvement of subcortical U-fibers.	Infectious	Virus mainly in oligodendrocytes (spaghetti and meat balls on EM), sometimes also in astrocytes
HIV encephalopathy or HIV dementia35	More or less symmetric, periventricular white matter. Sparing of subcortical U-fibers (low myelin turnover). Atrophy.	Infectious	Virus in microglia, on microscopy microglial nodules
CADASIL70	More or less symmetric, periventricular and deep white matter. Anterior temporal pole most striking, external capsule most often involved.	Vascular, genetic (NOTCH3)	Arteriopathy due to smooth muscle cell dysfunction and BBB dysruption due to pericyte involvement.
Inflammatory CAA69	Asymmetric white matter hyperintensities + microbleeds.	Both vascular and inflammatroy	Vasogenic edema
Lyme borreliosis		Infectious
Lymphoma	Periventricular white matter.	Tumor	Infiltrative small round blue cells
Mild encephalitis with reversible splenial lesion (MERS) or cytotoxic lesion of the corpus callosum (CLOCC)43	Splenium of corpus callosum, sometimes with extensive cerebral white matter involvement.	Inflammatory	Cytotoxic edema
MOGHE (Mild malformation with oligodendroglial hyperplasia and epilepsy)38	Resembles focal cortical dysplasia II, but with mainly white matter hyperintensity	Developmental	Oligodendrocyt hyperplasia
X-linked adrenoleukodystrophy48	Symmetric white matter, posterior > anterior. Most typical presentation: splenium, peritrigonal white matter and then corticospinal tract, other white matter	Metabolic	Peroxisomal enzym defect -> accumulation of VLCFA leading to astrogliosis
Metachromatic leukodystrophy49	Symmetric white matter with posterior > anterior. Most typical presentation: parieto-occipital and splenium involvement, sparing of perivenular myelin (tigroid pattern), initially sparing of subcortical U-fibers	Metabolic	Lysosomal enzym defect -> accumulation of sulfatides in glial cells and neurons. Demyelination without inflammation.
Krabbe or globoid cell leukodystrophy50	Symmetric periventricular white matter and cerebellar white matter	Metabolic	Lysosomal enzym defect with accumulation of GalCer in macrophages (globoid cells) -> destruction of oligodendrocytes
Canavan disease52	Symmetric white matter including subcortical U-fibers. Sparing deep white matter of corticospinal tract and corpus callosum. Macrocephaly.	Metabolic	Mutation in ASPA enzym, mainly present in oligodendrocytes -> myelin vacuolisation ->spongiform white matter. (not caused by high NAA)
Alexander disease	Symmetric white matter involvement anterior > posterior. Periventricular > subcortical white matter	Metabolic	Astrocytic inclusions with GFAP (intermediate filament of cytoskeleton)
Leigh syndrome53	Uncommon white matter involvement. Mainly/usually basal ganglia, thalami and brain stem.	Metabolic	Mitochondrial dysfunction leading to apoptosis
Herpes encephalitis17	White matter + cortex of limbic structures sometimes with microbleeds	Infectious	Initial inflammation with microglia, later hemorrhagic necrosis

T2 HYPERINTENSE BASAL GANGLIA AND/OR THALAMI

Disease	Location	Classification	Cause
Hypoxia, near drowning	Basal ganglia including thalamus+cortex	Vascular	Initially cytotoxic edema, later (if lucky) gliosis
Hypoxic Ischemic Encephalopathy in neonates12	Lentiform, ventrolateral thalamus	Vascular	Initially cytotoxic edema, later gliosis
Osmotic demyelination syndrome45	Basal ganglia, thalamus+central pons, white matter	Metabolic	First astrocyt injury, then oligodendrocyt injury
Acute Disseminated Encephalomyelitis41	Asymmetric basal ganglia, thalami+multifocal in white matter	Inflammatory	Vasogenic (reversible) and cytotoxic edema
Neurofibromatosis58	Basal ganglia (globus pallidus), thalami + brainstem and subcortical white matter	Genetic	FASI, intramyelinic edema
CO poisoning		Metabolic
Leigh syndrome53	Putamen (characteristic), globus pallidus, caudate, thalami, STN +brain stem	Metabolic	Mitochondrial dysfunction leading to apoptosis
Cryptococcosis33	Perivascular spread in basal ganglia, thalami+deep white matter and infratentorial	Infectious (opportunistic)	Gelatinous pseudocysts filled with fungi
Acquired Toxoplasmosis32	Basal ganglia, thalami+gray white junction and cerebellum	Infectious (opportunistic)	Target sign with central necrotic tissue, a hypo intense rim and an outer rim of encysted parasites
Creutzfeldt-Jakob disease55	Sporadic: Caudate, putamen and thalami +cortex Bovine/variant: thalamus (pulvinar)	Infectious (prion disease)	Vacuolisation of neurons and astrogliosis
Status epilepticus75	Pulvinar and hippocampus	Metabolic (glutamate)	Excitotoxic edema

T1 HYPERINTENSE BASAL GANGLIA AND/OR THALAMI

Physiological calcification	Globus pallidus
Disease	Location	Classification	Cause
Hypoxic Ischemic Encephalopathy12	Lentiform, Thalamus	Vascular	Hemorrhage and reactive astrogliosis
Hepatic encephalopathy57	Globus pallidus (most common), other basal ganglia+substantia nigra	Metabolic	Manganese
Wilson54	Putamen (most common), Globus pallidus, Caudate, Thalamus +tegmentum	Metabolic	Copper
Hyperparathyroidism, hypoparathyroidism	Symmetrical basal ganglia, periventricular (corona radiata) and dentate nuclei	Metabolic	Calcification
Japanese encephalitis53	Thalamus	Infectious	Hemorrhage
Neurofibromatosis58	Globus pallidus	Genetic	Mineralisation of FASI

masses in and near the ventricles

Choroid plexus cyst or xanthogranuloma	Trigone of lateral ventricle	Common incidental finding, in elderly patients	Cholesterol and lipid rich cysts with desquamated epithelium
Intrauterine choroid plexus cyst	In choroid plexus	Regresses at birth
Disease	Location	Classification	Cause
Intraventricular meningioma92	Trigone/atrium of lateral ventricle	Tumor: 40-70 yo	Meningothelial inclusion during embryology
Choroid plexus papilloma96	Trigone/atrium of lateral ventricle Fourth ventricle	Tumor: Cauliflower-like very vascular, intense enhancement	Choroid plexus epithelium
Low grade glial tumor: astrocytoma61, oligodendroglioma63	Trigone/atrium of lateral ventricle	Tumor: 10-40 yo	Glial cells
Lymphoma	Trigone/atrium of lateral ventricle	Tumor: Mainly elderly patients	Lymphoid small round blue cells
Subependymoma94	Frontal horn and body of lateral ventricle Fourth ventricle	Tumor: lobulated, cysts, firm tumor, mild or no enhancement in 5th and 6th decade	Subependymal region with ependymal and astrocyte processes; sometimes mixed histology
Central neurocytoma93	Frontal horn and body of lateral ventricle Septum pellucidum	Tumor: Bubbly mass, mixed cystic and solid, calcifications	Radial glial cells in the ventromedial quadrant
Ependymoma95	Fourth ventricle	Tumor: floor of fourth ventricle, squeezes out foramina, “plastic” tumor in children/infants	Ependymal cells derived from embryonic radial glia
Medulloblastoma	Fourth ventricle	Tumor: roof of fourth ventricle, children mainly <10 yo	Small round blue cells, very cellular tumor, different molecular subgroups
Germ cell tumors85	Posterior 3rd ventricle/pineal region	Tumor: in midline; mainly pineal or sellar region, pediatric population, peak 10-15 yo	Problem with migration of primordial germ cells or residual germ cells in midline