12 results
7 - Hypoxic Ischemic Encephalopathy in Term Neonates
- from Section 1 - Bilateral Predominantly Symmetric Abnormalities
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- By Mariasavina Severino, Children’s Research Hospital, Genoa, Italy
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 15-16
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Summary
Specific Imaging Findings
The findings in Hypoxic Ischemic Encephalopathy (HIE) are variable and depend on brain maturity, severity and duration of insult, and timing of imaging studies. In moderate-to-severe HIE at term, the central gray matter is the most frequently affected with lesions in the lentiform nuclei and thalami, typically adjacent to the posterior limb of the internal capsule (PLIC). Cortical abnormalities are characteristically found in the perirolandic area. These lesions are T1 hypointense and T2 hyperintense in the acute phase (first 2 days), becoming T1 hyperintense after 3–5 days. An early sign is the loss PLIC on conventional MR sequences. The most reliable sign of HIE, which also remains for a long time, is the reversal of normal PLIC T1 hyperintensity compared to the adjacent lentiform nucleus and thalamus.
In severe and prolonged HIE at term, there is diffuse brain swelling and edema, usually sparing the basal ganglia, brainstem, and cerebellum. The lesions rapidly evolve by cavitation, developing into multicystic encephalopathy. In mild HIE, typical MRI features are characterized by parasagittal lesions involving vascular boundary zones (watershed injury pattern). Diffusion imaging shows corresponding bright DWI signal and reduced apparent diffusion coefficient (ADC) values in the first 24 h. These abnormalities peak at 3–5 days and pseudonormalize by about the end of the first week. MR spectroscopy demonstrates lactate peak in the affected regions. A glutamine-glutamate (Glx) peak may also be elevated.
9 - Gangliosidosis GM2
- from Section 1 - Bilateral Predominantly Symmetric Abnormalities
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- By Mariasavina Severino, Children’s Research Hospital, Genoa, Italy
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 19-20
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Summary
Specific Imaging Findings
Imaging findings in Tay–Sachs (Infantile GM2 Gangliosidosis Type B) and Sandhoff diseases (Infantile GM2 Gangliosidosis Type O) are quite similar. The lesion pattern in a macrocephalic infant is highly suggestive and includes symmetrical hyperdensities within the thalami and/or basal ganglia on brain CT. The thalami are typically hyperintense on T1-weighted images and hypointense on T2-weighted images. In Tay–Sachs disease the posterior part of the thalami may be T2 hyperintense. The putamina, caudate nuclei and globi pallidi are swollen and hyperintense on T2-weighted images. Widespread white matter changes within the cerebral hemispheres are also noted with sparing of corpus callosum, anterior commissure, and posterior limbs of the internal capsules. Brain atrophy appears in the final stages of the disease. Diffusion imaging is usually unremarkable. Brain MRS shows decline in the NAA, increased choline and progressive elevation of myo-inositol. In juvenile and adult GM2 gangliosidosis, there is cerebral and cerebellar atrophy, generally in combination with slight white matter signal changes. A decrease in T2 signal intensity of the thalami is also found in a number of other diseases caused by genetic mutations and it seems to be a sign of lysosomal disease.
18 - Bilateral Perisylvian Polymicrogyria (BPP)
- from Section 1 - Bilateral Predominantly Symmetric Abnormalities
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- By Mariasavina Severino, Children’s Research Hospital, Genoa, Italy
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 37-38
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Summary
Specific Imaging Findings
In bilateral perisylvian polymicrogyria (BPP), MRI demonstrates an abnormal configuration of the cortical ribbon and irregular gray-white matter junction suggestive of multiple small gyri bilaterally around the sylvian fissures. The mildest forms of perisylvian polymicrogyria involve part of the perisylvian cortex, usually the posterior region, while the most severe forms extend beyond the perisylvian area to the frontal, occipital, and temporal lobes with a perisylvian gradient (i.e. maximal severity in the perisylvian cortex). The spectrum of cortical morphology is wide: the cortex may be normal to thick with a delicate or coarse appearance, and the cortical surface may range from bumpy and irregular to smooth. Moreover, the appearance of BPP depends on the stage of maturity/myelination of the brain: in unmyelinated regions, the inner surface of the polymicrogyric cortex looks thin and finely undulated, while in myelinated areas it looks thicker and relatively smooth. The underlying white matter usually appears decreased in volume. The sylvian fissures have an abnormally verticalized orientation extending far more posteriorly than normal into the parietal regions and may be abnormally forked along their course. The fronto-temporo-parietal opercula present an abnormally open appearance, which is frequently associated with an overlying large anomalous venous structure. CT may show abnormal sylvian fissures and thickened adjacent cortex.
16 - Glutaric Aciduria Type 1
- from Section 1 - Bilateral Predominantly Symmetric Abnormalities
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- By Mariasavina Severino, Children’s Research Hospital, Genoa, Italy
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 33-34
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Summary
Specific Imaging Findings
MR findings in glutaric aciduria type 1 (GA-1) in addition to macrocephaly include characteristic bilateral small anterior poles of temporal lobes with poor opercularization and widened sylvian fissure, subdural collections, and basal ganglia lesions. Central gray matter abnormalities variably include symmetric T2 hyperintensities and volume loss of the basal ganglia and dentate nucleus, with thalamus occasionally involved. In acutely affected areas there may be reduced diffusivity and MRS reveals elevated lactate with decreased levels of NAA. Abnormalities are often seen within the midbrain with involvement of white matter structures, tegmentum and substantia nigra and sparing of red nuclei, producing the “giant panda face” sign. The white matter may be primarily involved in GA-1, characteristically in the periven-tricular regions with sparing of the U-fibers and optic radiations. Diffusion may be persistently reduced with decreased ADC values within the lesions. Additional findings include subependymal nodules and pseudocysts.
Pertinent Clinical Information
The disease has a variable clinical presentation and severity. Patients may remain asymptomatic or mildly affected, with macrocephaly only, or they may present with encephalopathic crises in infancy or childhood after an initially normal development. These episodic crises typically occur following a trigger event (infection, immunization, surgery) and are characterized by hypotonia, spasticity, dystonia, rigidity, orofacial dyskinesia, seizures, opisthotonic posturing, decreased consciousness, and coma. Recovery is slow and often incomplete.
94 - Microcephaly
- from Section 3 - Parenchymal Defects or Abnormal Volume
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- By Mariasavina Severino, Children’s Research Hospital, Genoa, Italy
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 193-194
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Summary
Specific Imaging Findings
Microcephaly is characterized by a reduced (at least < 30%) cranio-facial ratio compared with age-matched normocephalic children. Primary congenital microcephaly refers to a small head size with relatively preserved brain architecture. Microcephalywith simplified gyral pattern shows a reduced number of gyri and shallow sulci (one-quarter to one-half of normal depth) without thickening of the cerebral cortex (cortical thickness < 4 mm). There is a correlation between the degree of microcephaly, the volume of white matter and the presence of simplified gyral pattern. Reduced white matter bulk and enlarged extra-axial spaces are frequent accompanying features. Other developmental brain anomalies are often associated, including callosal agenesis, dysgenesis or hypoplasia, periventricular nodular heterotopias, pontocerebellar hypoplasia, and abnormal myelination. Cortical malformation such as lissencephaly and polymicrogyria may also be present. Secondary microcephaly may present white matter T2 hyperintensities (consistent with gliosis, cavitations, demyelination), cortical malformations, and calcifications.
Pertinent Clinical Information
Microcephaly is a clinical observation defined as a head circumference over 2 standard deviations below the mean for age and gender; severe microcephaly is characterized by a head circumference over 3 standard deviations below the mean. Microcephaly may be present at birth, or it may become evident in the first few years of life when the head fails to grow while the face continues to develop at a normal rate, producing a child with a small head, a relatively large face, and slanted forehead. Patients may present with mental retardation (50%), epilepsy (40%), cerebral palsy (20%), and ophthalmologic disorders (20-50%).
23 - Megalencephalic Leukoencephalopathy with Subcortical Cysts
- from Section 1 - Bilateral Predominantly Symmetric Abnormalities
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- By Mariasavina Severino, Children’s Research Hospital, Genoa, Italy
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 47-48
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Summary
Specific Imaging Findings
MRI shows diffuse cerebral white matter swelling and T2 hyperintensity with involvement of U-fibers and early appearance of typical subcortical cysts, particularly in the frontotemporal regions, best shown by FLAIR and T1WI. Over time these cysts may increase in size and number. The corpus callosum and internal capsules are relatively preserved. Subtle signal changes may be present within the brainstem, especially along the pyramidal tracts. Cerebellar white matter is usually of a mildly abnormal signal and not swollen. The deep gray matter structures are intact and there is no abnormal contrast enhancement. Brain atrophy develops on follow-up studies. A more benign variant is characterized by milder initial findings with subcortical cysts limited to the temporal region. In this form, the white matter abnormalities and cysts decrease over time. In adults with the disease, atrophy is present instead of brain swelling, with enlargement of the ventricles and other CSF spaces. On ADC maps there is increased diffusivity of the affected white matter. MRS shows decreased levels of all metabolites in cystic areas and decreased NAA within white matter lesions.
Pertinent Clinical Information
Megalencephalic leukoencephalopathy with subcortical cysts (MLC) is characterized by early macrocephaly (developing during the first year of life) and delayedmotor and cognitive deterioration. Mild delay in gross motormilestones is followed by slowly progressive ataxia and spastic paraparesis. Mental deterioration and seizures develop in later stages of the disease. Minor head trauma may induce temporary deterioration. Extrapyramidal disorders (dystonia and athetosis), dysphagia and speech problems can appear in the second and third decades.
10 - Leigh Disease
- from Section 1 - Bilateral Predominantly Symmetric Abnormalities
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- By Mariasavina Severino, Children’s Research Hospital, Genoa, Italy
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 21-22
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Summary
Specific Imaging Findings
MR imaging in Leigh disease (LD) usually reveals bilateral symmetrical T2 hyperintense lesions of the deep gray matter and brainstem. Putamen is typically involved, followed by the caudate nuclei. The globi pallidi and thalami area less frequently affected. Brainstem lesions including the subthalamic nuclei, substantia nigra, red nuclei, colliculi, periaqueductal gray matter, and medulla oblongata are commonly present. Cerebellar dentate nuclei are also a frequent location of T2 hyperintensity. Spinal cord, hemispheric white matter and cerebral cortex involvement may occur. Acutely affected areas may show reduced diffusivity on ADC maps. MRS usually reveals elevated lactate, most prominent within the lesions. Normal MRS, however, does not exclude LD.
Pertinent Clinical Information
Leigh disease is a frequently lethal disorder that usually presents during infancy, and rarely during childhood and later in life. Developmental delay, seizures, and altered consciousness are the most common presenting symptoms. Generalized weakness, hypotonia, nystagmus, ataxia, dystonia, lactic acidosis and respiratory failure with apneas are also frequently present. Visceral manifestations comprise failure to thrive, cardiomyopathy, liver function impairment and proximal renal tubulopathy.
19 - Lissencephaly
- from Section 1 - Bilateral Predominantly Symmetric Abnormalities
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- By Mariasavina Severino, Children’s Research Hospital, Genoa, Italy
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 39-40
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Summary
Specific Imaging Findings
Lissencephaly is characterized by absent (agyria) or decreased (pachygyria) cortical convolutions, resulting in a smooth cerebral surface. The affected cortex is abnormally thick, usually measuring 10-15 mm in agyria with almost no visible sulcation, and 6-9 mm in pachygyria (also called “incomplete lissencephaly”) with the presence of only a few shallow sulci and broad gyri. Complete agyria or pachygyria are unusual, and most cases are a combination of agyria and pachygyria. The thick, smooth cortex characteristically shows a peripheral stripe of high T2 signal and low CT attenuation, corresponding to sparse cell zone. The white matter is very thin and may be reduced to periventricular areas only. Several different patterns of lissencephaly have been described depending on the severity of the gyral simplification and the gradient along the anterior to posterior axis, with good correlation between the phenotypic spectrum and the underlying genetic abnormality. The most severe pattern is characterized by complete agyria with smooth cerebral surface and absent opercularization (“figure eight” configuration of the brain). Children with LISI and TUBA1A mutations have predominant posterior lissencephaly with a posterior to anterior (P>A) gradient. TUBAIA mutations may also show perisylvian pachygyria with typical dysgenesis of the anterior limb of the internal capsules. Children with DCX mutations have predominant anterior lissencephaly, with anterior to posterior (A>P) gradient. Other lissencephaly-associated abnormalities may include microcephaly, commissural abnormalities (in particular callosal anomalies), brainstem abnormalities (such as severe hypoplasia of the pons and medulla) and abnormalities of the cerebellum (in particular hypo/dysplasia of the vermis).
30 - X-Linked Adrenoleukodystrophy (X-ALD)
- from Section 1 - Bilateral Predominantly Symmetric Abnormalities
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- By Mariasavina Severino, Children’s Research Hospital, Genoa, Italy
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 61-62
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Summary
Specific Imaging Findings
The childhood form of X-linked adrenoleukodystrophy (X-ALD) shows the typical parieto-occipital pattern (up to 85% of patients) with symmetric involvement of the white matter, splenium and posterior body of corpus callosum. The progression pattern is centrifugal and postero-anterior starting from the splenium with sparing of subcortical U fibers. Contrast enhancement and reduced diffusion at the advancing lesion margins are characteristic, corresponding to active demyelination, axonal damage and inflammation. CT may show dystrophic calcifications within the affected areas. Brain stem lesions involving the corticospinal, corticobulbar, visual, and auditory tracts are frequently associated. The frontal variant (about 15% of cases) shows involvement of the frontal periventricular white matter, the genu and anterior body of the corpus callosum and the anterior limbs of internal capsules; the outer borders of the lesions may enhance with contrast. The atypical presentation of childhood cerebral X-ALD (2.5% of cases) is characterized by combined but separate involvement of the frontal and parieto-occipital white matter. Central portions of the X-ALD lesions show high ADC and low FA values, correlating with histologic findings. In addition to nonspecific decrease in NAA with increased lactate and choline, MRS shows elevated myo-inositol levels, which correlate with disease severity.
Adrenomyeloneuropathy (AMN) in adults is characterized by spinal cord atrophy often with signal changes in the posterior limbs of the internal capsules, brainstem (with relative sparing of tegmental structures), and cerebellar white matter.
125 - Active Multiple Sclerosis
- from Section 4 - Abnormalities Without Significant Mass Effect
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- By Mariasavina Severino, Children’s Research Hospital, Genoa, Italy
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Book:
- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 257-258
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Summary
Specific Imaging Findings
Active multiple sclerosis (MS) plaques cause breakdown of the blood–brain barrier (BBB) and therefore enhancement on postcontrast MR images. Two enhancement patterns exist: uniform, reflecting the onset of a new lesion, and ringlike, indicating reactivation of an older lesion. Uniform enhancement may be faint, irregular, and with ill-defined margins. Peripheral ring-like enhancement is usually incomplete (“open”); however, it may form a full circle. There is no associated mass effect and no edema surrounding the enhancing area (except for tumefactive MS, which is discussed separately). Hyperacute plaques (first 24 h) may show restricted diffusion due to acute inflammation. On DWI acute lesions frequently show a ring pattern with hyperintense rim, while the center of the lesion has high ADC values. The diffusion findings and contrast enhancement, however, frequently do not coexist. Although MS plaques can be found throughout the brain, they have a predilection for periventricular white matter, corpus callosum, juxtacortical regions, optic radiations, as well as infra-tentorial locations. The enhancing lesions also follow this distribution. Ovoid appearance with orientation perpendicular to the ventricular surface is highly characteristic, but only on axial images. Microbleeds may be seen within MS plaques on T2* MR imaging, primarily with SWI. The detection rate of enhancing lesions is increased by delayed imaging, triple dose of contrast and use of magnetization transfer. The higher contrast dose may have a role in cases of diagnostic doubt following the standard dose.
33 - Alexander Disease
- from Section 1 - Bilateral Predominantly Symmetric Abnormalities
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- By Mariasavina Severino, Children’s Research Hospital, Genoa, Italy
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 67-68
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Summary
Specific Imaging Findings
The most common infantile form of Alexander disease (AD) is characterized by frontotemporal white matter abnormalities (CT hypodense, low T1 and high T2 signal) with typical anteroposterior progression pattern, involvement of U-fibers and possible cystic degeneration. The external and extreme capsules are usually involved. There are characteristic T1 hyperintense and T2 hypointense periventricular frontal rims, hyperdense on CT. The deep gray matter may be swollen and T2 hyperintense showing gradual volume loss. Brainstem abnormalities are primarily involving the medulla and midbrain. Contrast enhancement is seen in ventricular ependyma, periventricular rim, frontal white matter, optic chiasm, fornix, basal ganglia, thalamus, dentate nucleus, and brainstem. Hydrocephalus may occcur due to aqueductal stenosis. Atypical MRI findings are more commonly observed in juvenile and adult AD and include: predominant or isolated involvement of posterior fossa, multifocal tumor-like brainstem lesions, signal abnormalities or atrophy of the medulla or spinal cord and garland-like features along the ventricular wall. MRS may show markedly decreased NAA, with increased myo-inositol, choline, and lactate.
Pertinent Clinical Information
There are three clinical subgroups of AD: infantile (birth to 2 years), juvenile (2–12 years), and adult forms. Infantile AD presents with increasing macrocephaly, failure of normal development, seizures, serious feeding problems, and rapid neurologic deterioration with average survival of 3 years. In juvenile AD, macrocephaly is less frequent and patients usually suffer from progressive signs of bulbar dysfunction, developmental regression, ataxia and spasticity with average survival of 8 years.
72 - Septo-Optic Dysplasia
- from Section 2 - Sellar, Perisellar and Midline Lesions
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- By Mariasavina Severino, Children’s Research Hospital, Genoa, Italy
- Edited by Zoran Rumboldt, Medical University of South Carolina, Mauricio Castillo, University of North Carolina, Chapel Hill, Benjamin Huang, University of North Carolina, Chapel Hill, Andrea Rossi
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- Brain Imaging with MRI and CT
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- 05 August 2013
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- 08 November 2012, pp 147-148
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Summary
Specific Imaging Findings
The wide spectrum of imaging findings in septo-optic dysplasia (SOD) includes variable combinations of defects involving the midline brain structures, pituitary gland, optic nerves and eyes, olfactory bulbs, as well as other brain structures. Midline brain defects classically consist of complete or partial absence of the septum pellucidum with fused midline fornices (60% of cases) and/or corpus callosum abnormalities, such as agenesis, dysplasia or hypoplasia. The presence of a normal septum pellucidum does not rule out SOD. Pituitary gland malformations include anterior pituitary hypoplasia and/or ectopic posterior lobe and/or thin or interrupted pituitary stalk. Another characteristic feature is the hypoplasia of the optic nerves and chiasm, more commonly bilateral than unilateral. Frequently associated ocular anomalies include coloboma, anophthalmia, and microphthalmia. The olfactory bulbs may be absent or hypoplastic. Other brain malformations commonly associated with SOD are schizencephaly (so-called SOD-plus), polymicrogyria, gray matter heterotopia, and hippocampal malformations.
Pertinent Clinical Information
The diagnosis of SOD is clinical and made when two or more features of the classical triad of optic nerve hypoplasia, pituitary hormone abnormalities and midline brain defects are present. Only a third of patients present with all cardinal features of SOD. Visual deficits (nystagmus, diminished visual acuity, color blindness) due to optic nerve hypoplasia and ocular malformations are usually the first presenting feature of the condition, while endocrine dysfunction may become apparent later on. The extent of pituitary–hypothalamic dysfunction (60–80% of cases) is highly variable, ranging from isolated pituitary hormone deficit (in particular growth hormone deficiency) to panhypopituitarism.