leukodystrophies imaging

7/22/2019 Leukodystrophies Imaging

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Leukodystrophies


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Metachromatic leukodystrophy

Metachromatic leukodystrophy. (a)T2-weighted MR image demonstrates bilateral

confluent areas of high signal intensity in the periventricular white matter. Note theclassic sparing of the subcortical U fibers (arrowheads). (b)Contrast material-

enhanced MR image shows lack of enhancement in the demyelinated white matter, a

finding that is characteristic of metachromatic leukodystrophy.


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Metachromatic leukodystrophy. (a)T2-weighted MR image shows numerous linear

tubular structures with low signal intensity in a radiating (tigroid) pattern within the

demyelinated deep white matter. (b)T2-weighted MR image shows a punctate (leopard

skin) pattern in the demyelinated centrum semiovale, a finding that suggests sparing ofthe white matter. (c)On a contrast-enhanced T1-weighted MR image, the tigroid

pattern seen in aappears as numerous punctate foci of enhancement (arrows) within

the demyelinated white matter, which is unenhanced and has low signal intensity

(leopard skin pattern).


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Krabbes

disease

Krabbe disease in a 2-year-old boy.

T2-weighted MR image

demonstrates symmetric high-

signal-intensity areas in the deep

white matter. The internal andexternal capsules are also involved

(arrowheads). Note the bilateral

areas of abnormal signal intensity in

the thalami (arrows).


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MucopolysaccharidosisMucopolysaccharidosis in a 4-year-old boy with Hurler disease. (a)T1-weighted MR

image shows multiple well-defined areas of low signal intensity in the central and

subcortical white matter. (b)T2-weighted MR image demonstrates multiple well-defined

areas of high signal intensity in the deep and subcortical white matter.


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X-linked

Adrenoleukody

strophy

T2-weighted MR image

shows symmetric confluentdemyelination in the

peritrigonal white matter and

the corpus callosum.


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On a T1-weighted MR image, the

peritrigonal lesions appear

hypointense.

Gadolinium-enhanced T1-weighted MR image

reveals a characteristic enhancement pattern

in the intermediate zone (arrows) representing

active demyelination and inflammation.


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Atypical ALD(a)T2-weighted MR image shows involvement predominantly of the frontal lobe white

matter, genu of the corpus callosum, and anterior limbs of the internal capsule

(arrows). (b)Gadolinium-enhanced T1-weighted MR image shows linear enhancement

within the involved white matter and the anterior limbs of the internal capsule (arrows).


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Zellweger syndromeZellweger syndrome in a 5-month-old girl. (a)T2-weighted MR image shows extensive

areas of diffuse high signal intensity in the white matter. The gyri are broad, the sulci are

shallow, and there is incomplete branching of the subcortical white matter, findings that

suggest a migration anomaly with pachygyria. (b)On a T1-weighted MR image, the white

matter abnormalities demonstrate low signal intensity.


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MELASMELAS syndrome in a 10-year-old boy with migrating infarction.(a)Initial T2-

weighted MR image shows a high-signal-intensity lesion in the left occipital lobe

(arrows). Prominent cortical sulci are seen in the right occipital lobe, a finding that

suggests cortical atrophy. (b)On a contrast-enhanced T2-weighted MR image, the

lesion demonstrates no enhancement. (c)Follow-up MR image obtained 15 months

later shows another lesion in the left temporal area (arrowheads).


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Leigh diseaseLeigh disease in a 2-year-old boy. (a)T2-weighted MR image shows bilateral high-

signal-intensity areas in the putamen and globus pallidus (arrows). (b)On a T1-

weighted MR image, the lesions demonstrate low signal intensity (arrows).


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Canavan diseaseCanavan disease in a 6-month-old boy with macrocephaly. (a)T2-weighted MR image shows

extensive high-signal-intensity areas throughout the white matter, resulting in gyral expansion

and cortical thinning. Striking demyelination of the subcortical U fibers is also noted. (b)T1-

weighted MR image shows demyelinated white matter with low signal intensity.


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Pelizaeus-

Merzbacher

disease

PMD in a 7-month-old boy. T2-

weighted MR image reveals

almost no myelination of the

cerebral white matter. The

subcortical white matter is also

involved, as are the internal and

external capsules (arrowheads).


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Alexanderdisease

Alexander disease in a

5-year-old boy withmacrocephaly. (a)T2-

weighted MR image

shows symmetric

demyelination in the

frontal lobe white

matter. The internal andexternal capsules and

parietal white matter

are also involved.


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The MRI criterion for a diagnosis of hypomyelination is anunchanged pattern of deficient myelination on two successive MRIscans at least 6 months apart. One of the MRI scans should havebeen obtained at the age of more than 1 year.

Fully myelinated white matter has high T1 signal and low T2 signal.

The T1 shortening occurs before T2 shortening and is moreprominent. Consequently, deposition of some myelin may result inlow, intermediate or high T1 signal of the white matter, dependingon the amount of myelin deposited, whereas the white mattersignal is still high on T2-weighted images.

At first glance, all hypomyelinating disorders have a similar

appearance on MRI with mild T2 hyperintensity of much or almostall cerebral hemispheric white matter and a variable T1 signalintensity.


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The diagnosis of 4H syndrome is based on hypomyelination on MRI,

hypogonadotropic hypogonadism and hypodontia. T2 hypointensity of optic radiation, pyramidal tracts at the level of the

posterior limb of the internal capsule and anterolateral part of the thalamus .The cerebellar white matter often has a mild T2 hyperintensity and the dentatenucleus stands out as relatively dark.

Another dominant feature is cerebellar atrophy, usually already seen before

the age of 10, a feature uncommon in other hypomyelinating disorders.

The sagittal T1-weighted image

shows cerebellar atrophy (A).

The axial

T2-weighted image (B) shows

relatively lower signal of theanterolateral part of the

thalamus (white arrow),

pyramidal tract at the

level of the posterior limb of the

internal capsule (black arrow)

and the optic radiation (white

open arrow).

4H Syndrome


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Hypomyelination with

atrophy of brainstem and

cerebellum

A, Axial T2W image, patient aged 18months. The cerebral white mattercontains little myelin. The putamenis mildly reduced in size(arrowhead). The thalamus, caudatenucleus, and globus pallidus (arrow)have a normal size.

B, Sagittal T1W image, patient aged18 months. The cerebellar vermis isslightly atrophic.

C, Axial T2W image, patient aged 6years. At 6 years, thehypomyelination of the cerebralwhite matter is unchanged. The

putamen is no longer visible. Thehead of the caudate nucleus ismildly reduced in size. The thalamusand globus pallidus (arrow) arenormal.

D, Sagittal T1W image, patient aged6 years. The cerebellar atrophy has

increased.


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Fucosidosis

Axial T2-weighted images of a 1-year-old female with fucosidosis demonstrate pronounced

T2 hypointensity of the globus pallidus (white open arrow, A) and substantia nigra (white

arrow, B). The optic radiation has a lower signal than the adjacent white matter

(black arrow, A).

Characteristic MRIfeatures include a

dark globus pallidus

and often also

substantia nigra on

T2-weighted images.


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Infantile GM1/2 Gangliosidosis

Characteristic MRI features are mild T2 hyperintensity of the caudate

nucleus and putamen with signs of diffuse hypomyelination,

contrasting with a normal T2 signal intensity of the corpus callosum,

indicating more complete myelination of this structure. The

anterolateral part of the thalamus was slightly abnormal in signal in a

few patients.

Axial T2-

weighted

images of a 1-

year-old

female with

GM2

gangliosidosis

display

hypointensity

of the corpus

callosum

(white arrow,

A) and T2

hyperintensity

of the basal

ganglia (black

arrow, B).


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Hypomyelination with congenital cataract

MRI of a 3-year-old malewith HCC. The axial T2-

weighted image shows

prominent T2

hyperintensity (black arrow,

A) and the

sagittal T1-weighted imagedisplays T1 hypointensity

(white arrow, B) of the

periventricular and deep

white matter.

Hypomyelination is combined with areas of prominent T2 hyperintensity andT1 hypointensity in the periventricular and deep cerebral white matter, indicating focal

lesions. Other hypomyelinating disorders, such as 4H syndrome and GM1 and GM2

gangliosidosis may also display some additional

T1 hypointensity of the deep cerebral white matter, but it is the contrast with the more

normal appearance of the subcortical white matter on T1-weighted images that makes HCC

distinct from other disorders.


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PMD

The majority of patients with PMD have a strikingly homogeneous T2 signal of the

cerebral white matter, often in combination

with hypointensity on T1-weighted images. It is striking that the tigroid pattern of

myelin deposition described in the histopathology of PMD is not observed on MRI

scans.

The axial T2-weighted

image in a 1-year-old

male with PMD shows

a strikingly

homogeneous T2

signal intensity of thecerebral

white matter (A) as

compared to a 5-year-

old male with 4H

syndrome (B).


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PMLD

An MRI feature of PMLD patients consists of prominent T2 signal

hyperintensity of the pons. The pontine abnormalities either consist of a

global T2 hyperintensity often associated with T1 hypointensity of the pons

or of T2 hyperintensity and T1 hypointensity confined to the pyramidal

tracts at this level.

Axial T2-weighted

images of two male

patients with PMLD

(age 39 years in A, age

6 years in B) at the

level of the pons showT2

hyperintensity, either

in the pyramidal tracts

alone (white arrow, A)

or in the entire pons

(black arrow, B).


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Salla disease

Classical Salla disease has no distinct MRI features .The pattern of T2

hyperintensity of the subcortical white matter contrasting with T2 hypointensity of

the remaining cerebral white matter, seen in several PMLD patients, was also seen

in two patients with Salla disease, however, without the typical pons

abnormalities of PMLD. MRSN

The axial T2-weighted

image of a 16-year-old

male with Salla disease

demonstrates

hyperintensity of the

subcortical white

matter, characteristic of

patients in Clusters 7 and8 (A), as compared to

more diffuse

hyperintensity of the

cerebral white matter in

a 19-year-old female with

hypomyelination (B).


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MRI study of brain shows:

Diffuses cerebral white matter

involvement. Early

involvement of sub cortical

white matter. Sub corticalwhite matter cysts iso intense

to Csf representing white

matter paucity in temporal

regions. Basal ganglia and

internal capsules spared.

Cerebral cortical atrophy.Minimal involvement of

Cerebellar white matter. On

MRS reduced NAA and slightly

raised Choline peak.


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Vander Knaap Leukoencephalopathy

Imaging findings of bilateral diffuse white matter disease,involvement sub cortical white matter with cysts, sparingbasal ganglia and internal capsules with Macrocephalyclinically goes in favour of Van der Knaap disease.

Abbreviations and Syn:

1. MLC: Megaloencephalic leukoencephalopathy withsubcortical cysts, formerly known as Vacuolatingmegaloencephalic leukoencephalopathy with benign,slowly progressive course.2. VWM: Leukoencephalopathy with Vanishing white

matter (WM), Alternatively called CACH (Childhood ataxiacentral hypomyelination)3. WML: White matter disease with lactate.4. H-ABC: Hypomyelination with atrophy of the basalganglia (BG) and cerebellum.

leukodystrophies imaging

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