White Matter and Neurodegenerative diseases Flashcards
(165 cards)
1
Q
gray matter are composed of
A
neuronal cell bodies
2
Q
white matter is composed of
A
long processes of neurons
3
Q
white matter is named white matter because of the
A
axonal processes wrapped by the myelin sheaths, and it is the lipid composition of these sheaths for which white matter is named
4
Q
cerebral white matter diseases are classified into two broad categories, namely
A
demyelination and dysmyelination
5
Q
an acquired disorder that affects normal myelin
A
demyelination
6
Q
an inherited disorder affecting the formation or maintenance of myelin and thus is typically encountered in the pediatric population
A
dysmyelination
7
Q
four main categories of demyelinating diseases
A
primary/immune-mediated, ischemic, infectious and toxic and metabolic
8
Q
classic example of a primary or immune-mediated demyelinating disease and is the most common nontraumatic cause of neurologic disability in young adults
A
Multiple sclerosis
9
Q
it is an autoimmune disorder affecting the CNS and is a disease characterized by immune dysfunction with the production of abnormal immunoglobulins and T cells, which are activated against myelin and mediate the damage associated with the disease
A
Multiple sclerosis
10
Q
age of onset of MS and gender predilection
A
between 20 and 40 years, with 10% of cases presenting in individuals older than 50 years, female predominance
11
Q
tx for MS that suppress the activity of the T cells, B cells and macrophages that are thought to lead the attack on myelin sheath
A
B-interferon and antineoplastic drugs
12
Q
Important characteristic of MS symptoms
A
multiplicity and tendency to vary over time
13
Q
key differentiating feature between MS and other white matter conditions, such as osmotic myelinolysis and PRES
A
inflammation
14
Q
this MR sequence provides the best visualization of supratentorial white matter lesions
A
FLAIR
15
Q
MR sequence that provides better visualization of infratentorial white matter lesions aside from FLAIR that is used in supratentorial lesions
A
STIR or PD
16
Q
active MS lesions have imaging appearance of
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enhancing lesions with restricted diffusion on DWI
17
Q
chronic MS lesions have imaging appearance of
A
abnormal high SI T2, persists, reflecting residual scarring /gliosis
18
Q
focal proliferation of astroglia at the site of injury is termed
A
gliosis
19
Q
dark lesions of MS are seen in
A
severe cases, where there is actual loss of neuronal tissue that shows dark signal on T1
20
Q
although many white matter lesions are nonspecific in nature, these lesions are suggestive of certain white matter disease when they are seen in the periependymal (abutting the ependyma, juxtacortical (gray-white cortical junction) or lesions involving the posterior fossa structures
A
MS
21
Q
periventricular lesions that are ovoid and aligned perpendicular to long axis of ventricles are suggestive of
A
MS
22
Q
areas wherein ischemic changes are rare and if lesions are seen in these regions, a primary demyelination condition should be considered
A
cerebellar and cerebral peduncles as well as the corpus callosum, medulla and spinal cord
23
Q
how to differentiate MS lesions from ischemic changes in the brainstem
A
MS lesions are more peripheral, in contrast to ischemic changes which tend to be centrally located
24
Q
characteristic flame-shaped configuration with a periependymal or juxtacortical location
A
MS
25
form of MS that may present as a large, conglomerate, deep white matter mass that can be mistaken fro neoplas,
Tumefactive MS or Tumefactive demyelinating lesions
26
imaging characteristics of Tumefactive MS that may help differentiate them from neoplasm
peripheral crescentic rim of contrast enhancement which represents the advancing leading edge of active demyelination. there is also paucity of perilesional edema as well as relative lack of mass effect for lesion size
27
whenever there is a focal abnormality of the spinal cord detected, this must be in the differential diagnosis
Demyelinating MS plaque
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spinal cord MS plaques typically appears as
well defined, less than one to two vertebral segments in the craniocaudal dimension, and less than 50% of the cross-sectional area of the spinal cord often affecting the peripheral white matter
29
small-vessel ischemic changes within the deep cerebral white matter that are seen with such frequency in middle age (>50 to 60 years). this represents an arteriosclerotic vasculopathy of the penetrating cerebral arteries
Age-related demyelination
30
more susceptible to ischemic injury because it is supplied by long, small-caliber penetrating end arteries without significant collateral supply
deep white matter
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Represents an arteriosclerotic vasculopathy of the penetrating cerebral arteries
Age-related demyelination
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These areas are usually spared from ischemia because of dual blood supply, which decreases their vulnerability to hypoperfusion
cortex, subcortical “U” fibers, central corpus callosum, medulla, midbrain and cerebellar peduncles
33
Histologically, areas of infarction demonstrate _____ in age-related demyelination
Axonal atrophy with diminished myelin
34
Multi-infarct dementia is called
Binswanger disease
35
Refers to small infarcts (5 to 10mm)
Lacunar infarcts
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Lacunar infarcts are commonly seen in
Basal ganglia, typically upper 2/3 of putamen
37
Involvement of the callosal-septal interface is quite specific for what white matter disease
MS
38
These white matter lesions are more prominent in any patient with a vasculopathy, such as related to atherosclerosis and vascular risk factors(hpm, dm, hyperlipidemia, coronary artery disease, smoking); hypercoagulable conditions; vasculitis (lupus, sarcoid, polyarteritis nodosa, Behcet syndrome) or drug related vasculopathy
Nonspecific punctate white matter lesions (small bright lesions on T2)
39
A young adult female with prior miscarriages presenting with headaches/migraines and ischemic white matter changes are suggestive findings of _______. It is where circulating antiphospholipid antibodies (cardiolipin or lupus anticoagulant antibodies) lead to hypercoagulable state with resultant white matter and ischemic changes
Antiphospholipid syndrome
40
Condition with proliferation of tiny collateral vessels presenting a a “puff of smoke”
Moyamoya disease or syndrome
41
Moyamoya disease refers to
Idiopathic form
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Moyamoya syndrome refers to
When the underlying etiology is known, such as fibromuscular dysplasia, marfan syndrome, NF1, SLE, down syndrome
43
Drug induced vasculopathy is most commonly seen with what drugs
Methamphetamine and sympathomimetic drugs
44
Normal anatomic finding that may mimic pathology. Consists of an area of high signal on T2 along the tips of frontal horns. Histologic studies show a loose network of axons with low myelin count. This allows transependymal flow of CSF, resulting in a focal area or T2 prolongation
Ependymitis granularis
45
With age as well as significant vascular risk factors, prominent periventricular T2 hyperintensity may be noted along the entire length of the lateral ventricles, and this may be referred to as
Senescent periventricular hyperintensity or periventricular halo
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These structures may mimic deep white matter or lacunar infarcts. They are blood vessels that penetrate into the brain parenchyma, that are enveloped by CSF and a thin sheath of pia
Prominent perivascular spaces/Virchow-Robin spaces
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Virchow-Robin spaces are commonly located in the
Centrum semiovale, lower basal ganglia at the level of anterior commisure, where the lenticulostriate arteries enter the brain parenchyma
48
Important means for differentiating a periventricular space from a parenchymal lesion is the use of
PDW or FLAIR
49
Difference between perivascular space and ischemic lesions in FLAIR and PDW
Perivascular spaces- CSF signal on all sequences
| Ischemia- unless cavitated with cystic change, will be bright as a result of presence of associated gliosis
50
Difference in the location of lacunar infarcts and perivascular spaces
Lacunar infarcts- upper 2/3 of corpus striatum, bec they reflect end-arteriole infarcts in the vascular distribution
Perivascular spaces- smaller, bilateral, often symmetric within the inferior 3rd of striatum, where vessels enter the anterior perforated substance
51
If a cystic lacunae has proteinaceous content, it may appear
Hyperintense on FLAIR
52
Inheritable condition relating to Notch 3 mutation on chromosome 19. This condition presents with ischemic changes, often in middle age. Presence of subcortical anterior temporal and medial frontal lesions is relatively specific for this condition
CADASIL disease (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy)
53
Heterogeneous group of disorders which are associated with inflammation of blood vessels leading to a variety of ischemic manifestations ranging from ischemic brain lesions, cerebral perfusion deficits, intracerebral or subarachnoid hemorrhage to vessel stenosis
CNS vasculitis
54
Laboratory tests to support diagnosis of vasculitis
ESR, C-reactive protein level, rheumatoid factor and compliment level
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idiopathic vasculitis limited to the brain and spinal cord typically observed in the 5th and 6th decades of life. this condition is associated with an elevation in ESR. Angiography may show segmental irregularity and narrowing of both small and medium-sized parenchymal and leptomeningeal blood vessels
Primary angiitis of the CNS (PACNS)
56
Autoimmune disorder which presents with white matter lesions (75%) as well as spectrum of neurologic and neuropsychiatric manifestations such as psychosis, stroke, headaches, and neurocognitive deficits. Peak age onset in second to fourth decades of life
SLE
57
half of SLE patients, aside from white matter lesions, have
cerebral atrophy
58
Large perivascular spaces are occasionally noted within the _____ and referred to as giant perivascular spaces
caudal aspect of the basal ganglia
59
progressive occlusive condition of the supraclinoid or terminal aspects of the internal cerebral arteries. It is a condition of children and young adults with a bimodal age distribution (first peak 4 years of age and second peak 30 to 40 years of age)
Moyamoya disease
60
characteristic findings include marked narrowing and occlusion of the terminal internal cerebal arteris (usually bilateral, but may be asymmetric and occassionally unilateral), with formation of a diffuse extensive network of tiny collateral vessels throughout the deep gray matter structures
Moyamoya disease
61
On angiography, Moyamoya disease shows enhancement of the tiny collateral vessels in the deep gray matter structures resulting in a dense blush of contrast, giving rise to the term ____
"puff of smoke"
62
Various infectious agents may result in white matter disease, either directly or indirectly, and most of them are
viral
63
most common fatal encephalitis
Herpes encephalitis
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form of herpes encephalitis which occurs in children and adults is caused by
HSV type 1 (oral type)
65
neonatal herpes encephalitis is usually caused by
HSV type 2 (genital herpes)
66
this viral encephalitis has a particular predilection for the limbic system, with localization of infection to temporal lobes, insular cortex, subfrontal area and cingulate gyrus. Imaging reveals primarily T2 hyperintensity of the involved cortex and subcortical structures, presenting as encephalitis with variable contrast enhancement. hemorrhage within the area is strongly supportive of the diagnosis
HSV type 1
67
a postinfectious and postvaccinal encephalomyelitis, typically occurs after a viral illness or vaccination, with measles, rubella, varicella, and mumps being the most common agents. this condition is considered an immune-mediated inflammatory demyelinating disease, but sometimes it has no recognized antecedent infection or inciting malady
Acute disseminated encephalomyelitis (ADEM)
68
theory behind ADEM
body's antiviral immune reaction cross-reacts with myelin sheaths, resulting in an acute, aggressive form of demyelination. this unintended antiviral response against myelin is a result of shared molecular homology between viral proteins and normal human CNS proteins
69
Demyelinating lesions associated with ADEM typically begin approximately how man weeks after a viral infection
2 weeks
70
lesions in ADEM primarily involve white matter, but gray matter may also be affected. MRI demonstrates multifocal or confluent white matter lesions similar to those of MS. A differential feature of ADEM is
a monophasic illness, unlike MS, which has a remitting and relapsing course. if the majority of the identified white matter lesions enhance, this suggests a monophasic demyelinating process
71
represents a reactivated, slowing progressive infection caused by measles virus. children between the ages of 5 to 12 years who have had measles, usually before the age of 3 years are typically affected. MRI demonstrates patchy areas of periventricular demyelination as well as lesions of the basal ganglia
Subacute sclerosing panencephalitis
72
seen in a wide range of immune-compromised individuals, ranging from those treated with immunosuppressants and cytotoxic agents to patients with AIDS. Represents a reactivation of a latent JC polyomavirus, which infects the oligodendrocytes, resulting to widespread demyelination. this usually involves the deep cerebral white matter, with subcortical U-fiber involvement, but spares the cortex and deep gray matter. lesions are characterized by lack of mass effect, contrast enhancement and hemorrhage and are typically located in the parietooccipital region
Progressive multifocal leukoencephalopathy (PML)
73
HIv involvement of the brain presents as
subacute encephalitis, referred to as AIDS dementia complex or diffuse HIV encephalopathy
74
characterized clinically by a progressive dementia without focal neurologic signs. It does not appear to be the result of a direct infection of the neurons or macroglia (CNS support cells, astrocytes, oligodendrocytes), instead, the active infection develops in the micoglia (brain macrophages). the cytokines and excitatory compounds that are produced as a result of this infection have a toxic effect on adjacent neurons
HIV encephalopathy
75
HIV encephalopathy most often results in
mild cerebral atrophy without a focal abnormality. occasionally, it causes focal or diffuse white matter hyperintensities on T2. typically, HIV white matter involvement presents as subtle, diffuse T2 hyperintensity that often is bilateral and relatively symmetric. this supratentorial white matter signal abnormality is ill-defined and often involves a large area, in contrast to the dense lesions that are characteristic of PML. they do not demonstrate contrast enhancement
76
idiopathic white matter lesions in younger patients are usually idiopathic, some have correlated it with
post viral infection
77
disorder that results in characteristic demyelination of the central pons. most commonly seen in patients with electrolyte imbalance, particularly involving the hyponatremia, that are rapidly corrected, giving rise to the term "osmotic demyelination syndrome". This condition occurs most commonly in children and alcoholic with malnutrition
Central pontine myelinolysis (CPM)
78
clinical course of CPM is classically described as biphasic, beginning with a generalized encephalopathy caused by hyponatremia, which usually transientrly improves, following initial correction of sodium. this is followed by a second neurologic syndrome, which occurs 2 to 3 days following correction or overcorrection of hyponatremia caused by myelinolysis. this latter phase is characterized by a rapidly evolving corticospinal syndrome with quadriplegia, acyte changes in mental status and a ____ in which a patient is mute, unable to move, and occasionally comatoise
"Locked-in" state
79
characteristic features of this demyelinating process include minimal to no mass effect, even when very large, and essentially no contrast enhancement or hemorrhage. A very low T-cell count reflecting an ICC status is also key to diagnosis
Progressive multifocal leukoencephalopathy
80
in an immunocompetent patient, differential consideration for PML lesions would include ____, which can have a similar imaging appearance, but without such defined subcortical U-fiber extension
posterior reversible encephalopathy syndrome
81
pathophysiology of CPM relates to a _______ with the distribution of CPM changes paralleling the distribution of oligodendroglial cells within the central pons, thalamus, globus pallidus, putamen, lateral geniculate body and other extrapontine sites termed extrapontine myelinolusis
disturbance in the physiologic balance of osmolality within the brain tissue. Oligodendroglial cells are most susceptible to CPM-related osmotic stresses. There is intramyelinic splitting, vacoulization and rupture of myelin sheaths, presumably because of osmotic effects. However, there is preservation of neurons and axons
82
Difference between MS and osmotic demyelination
no inflammatory reaction associated with osmotic demyelination, unlike MS, with marked perivascular inflammation
83
condition characterized by signal changes within the brain parenchyma, primarily involving the posterior vascular distribution. MRI reveals relatively symmetric areas of bilateral subcortical and cortical vasogenic edema within the parietoocipital lobes
Posterior reversible encephalopathy syndromes (PRES)
84
leading theory behind PRES
temporary failure of the autoregulatory capablities of the cerebral vessels, leading to hypoperfusion, breakdown of BBB, and consequent vasogenic edema, but no acute ischemic changes. increased perfusion pressure is sufficient to overcome the BBB, allowing extravasation of fluid, macromolecules and even RBCs into the brain parenchyma
85
preferential involvement of the parietal and occipital lobes in PRES is thought to be related to the
relatively poor sympathetic innervation of the posterior circulation
86
Conditions that leads to characteristic clinical and radiologic presentation of PRES
tx with cyclosporin A or tacrolimus (FK506), acute renal failure/uremia, hemolytic uremic syndrome, eclampsia, thrombotic thrombocytopenia purpura and tx with a wide variey of chemotherapeutic agents, including interferon, tx of Alzheimer disease
87
When the imaging findings of PRES are noted in the setting of tx with an amyloid removing agent, the condition is termed
amyloid-related imaging abnormalities (ARIAs)
88
True or false: hypertensionis often associated with PRES but may be relatively mild and is not universally present, especially in the setting of immunosuppresion.
true
89
rare form of demyelination seen most freq in alcoholics. characterized by demyelination involving the central fibers (medial zone) of corpus callosum, although other white matter tracts may be involved, including anterior and posterior commisures, the centrum semiovale, and the middle cerebral peduncles. this is felt to reflect a form of osmotic demyelination
Marchiafava-Bignami disease
90
Most common symptom of Marchiafava-Bignami disease
Nonspecific dementia
91
metabolic disorders caused by thiamine (B1 vitamin) deficiency secondary to poor oral intake in severe chronic alcoholics (most common association), hematologic malignancies or recurrent vomiting in pregnant patients
Wernicke encephalopathy and Korsakoff syndrome
92
Wernicke encephalopathy and Korsakoff syndrome may occur in many different non-alcoholic related pathologic conditions that share the common denominator of
malnutrition
93
characteristic lesions in Wernicke encephalopathy and Korsakoff syndrome include
lesions of the deep gray matter and periaqueductal gray matter
94
clinical triad of Wernicke encephalopathy and Korsakoff syndrome
acute onset of ocular movement abnormalities, ataxia and confusion
95
if persistent learning and memory deficits are present in patients with Wernicke encephalopathy, the symptom complex is termed
Wenicke-Korsakoff syndrome
96
Typically, PRES is not associated with cytotoxic edema or parenchymal hemorrhage. However, in more severe cases, this condition may go on to result in
varying degree of hemorrhage (micropetechial to frank parenchymal hemorrhage) and ischemia
97
In the acute stage of Wernicke encephalopathy and Korsakoff syndrome, findings in MRI include
T2 hyperintensity or contrast enhancement of the mammillary bodies, basal ganglia, thalamus, and brainstem, with periaqueductal involvement
98
chronic stage of Wernicke encephalopathy and Korsakoff syndrome may include
atrophy of mamillary body involvement
99
chronic stage findings of Wernicke encephalopathy and Korsakoff syndrome is very similar to what condition, which supports the notion that enzymatic deregulation in Leigh disease is tied in some fashion to thiamine metabolism
Leigh disease
100
radiation may result in damage to the white matter secondary to a radiation-induced vasculopathy. this condition usually follows a cumulative dose in excess of 40 Gy delivered to the brain and occurs 6 to 9 months after treatment
radiation leukoencephalitis
101
appearance of radiation leukoencephalitis
abnormal high T2 signal, involving confluent areas of white matter extending to involbe the subcortical U finvers in the distribution of the irradiated brain
102
major hazards related to CNS radiation
radiation necrosis and radiation arteritis
103
radiation necrosis may occur when after radiation
several weeks to years after radiation, but is most commonly occurs between 6 and 24 months after radiation
104
radiation necrosis is rarely noted at less than 6 months after tx unless this was employed
gamma knife
105
radiation necrosis typically presents as
enhancing lesion with mass effect and ring enhancement or as multiple foci of enhancement, mimicking recurrent neoplasm
106
radiation may also induce ____ within the radiation field, which may appear similar to cryptic vascular malformations
telangiectasia
107
valuable in distinguishing between tumor recurrence and radiation necrosis
PET and MR spectroscopy
108
MRS findings in necrosis
small lactate and lipid peak (0.9 to 1.3 ppm) with reduction in all other major metabolites
109
large vessels included with the radiation port ay undergo
radiation-induced endothelial hypertrophy, medial hyalinization and fibrosis. net result is progressive vascular narrowing that may be obliterative in nature
110
progressive vascular narrowing in radiation-induced endothelial hypertrophy often involves the _____ in children who have undergone irradiation of the parasellar regions for tx of tumors
cavernous and supraclinoid portions of the carotid arteries
111
when this chemotherapeutic drug (intrathecal or systemic) is administerd in combination with CNS radiation, these agents may have a synergistic effect in causing marked white matter abnormalities. it is theorized that low-dose radiation alters the BBB, alowing increased penetration of this drug to neurotoxic levels
Methotrexate
112
Methotrexate neurotoxicity combined with radiation therapy are most freq seen in children being treated for
leukemia
113
this condition of leukemic patients with methotrexate and radiation therapy results in diffuse destructive changes to the brain characterized by symmetric corticomedullary junction and basal ganglia calcifications
mineralizing microangiopathy
114
more serious but less common complication of methotrexate and radiation therapy is ____. this process results in widespread damage to the white matter, consisting of demyelination, necrosis and gliosis
necrotizing leukoencephalopathy
115
also referred to as leukodystrophies, are disorders in which myelin is abnormally formed or cannot be maintained in its normal state because of an inherited enzymatic or metabolic disorder
Dysmyelinating diseases
116
these conditions are characterized by the progressive destruction of myelin owing to the accumulation of varous catabolites, depending on the specific enzyme deficiency. children often present clinically with progresive mental and motor deterioration
Dysmyelinating diseases
117
most common of the leukodystrophies. it is transmitted by an autosomal recessive pattern and is the result of a deficiency of the enxyme arylsulfatase A. MRI demonstrares progressive symmetric areas of nonspecific white matter involvment with sparing of the subcortical U fibers
Metachromatic leukodystrophy
118
a sex-linked recessive condition (peroxisomal enzyme deficiency) occuring only in boys. Typical age of onset is between 5 and 10 years of age. these patients often have symptoms related to the adrenal gland, such as adrenal insufficiency or abnormal skin pigmentation
adrenal leukodystrophy
119
adrenal leukodystrophy has a striking predilection for the
visual and auditory pathways, presenting with symmetric involvement of the periatrial white matter and extension into the splenium of the corpus callosum
120
aka subacute necrotizing encephalomyelopathy, is a mitochondrial enzyme defect that commonly manifests in infancy or childhood (usually younger than 5 years). It has histopathologic findings similar to those of Wernicke encephalopathy
Leigh disease
121
characteristic finding in leigh disease is
involvement of the periaqueductal gray matter. in contrast to Wernicke encephalopathy, there is sparing of the mamillary bodies
122
these inherited mitochondrial abnormalities are caused by point mutations of mitochondrial DNA or mitochondrial RNA and represent progressive neurodegenerative disorders characterized clinically by strokes, stroke-like events, nausea, vomiting, enephalopathy, seizures, short stature, headaches, muscle weakness, exercise intolerance, neurosensory hearing loss and myopathy
MELAS (mitochondrial myelopathy, encephalopathy, lactic acidosis, stroke-like episodes) and MERRF (myoclonic epilepsy and ragged fibers)
123
white and gray matter involvement in metachromatic leukodystrophy
WM: diffusely affected
GM: none
124
white and gray matter involvement in adrenoleukodystrophy
WM: symmetric occipital and splenium of corpus callosum
GM: none
125
white and gray matter involvement in Leigh disease
WM: focal areas of subcortical white matter
GM: basal ganglia and periaqueductal gray
126
white and gray matter involvement in Alexander disease
WM: frontal
GM: none
127
white and gray matter involvement in Canavan disease
WM: diffusely affected
GM: Vacuolization of cortical gray matter
128
rarest of the leukodystrophies adn may appear as early as the first few weeks of life. Patients have an enlarged brain and have mircocephaly on examination. typically, these patients present with seizures, spasticity and delayed developmental milestones
Alexander and Canavan disease
129
this leukodystrophy is caused by a deficiency of the enzyme aspartoacylase, which leads to the buildup of NAA in the brain and subsequent myelin destruction. this results in the pathognomonic MRI spectra consisting of a giant NAA peak
Canavan disease
130
CSF is produced predominantly by
choroid plexus of lateral, third and fourth ventricle
131
CSF flow
from lateral ventricles --> foramen of monroe --> third ventricle --> cerebral aqueduct --> fourth venricle --> foramen of Lushcka to lateral fourth ventricular foramina and foramen of Magendie to medial fourth ventricular foramina --> basal cisterns and over the surfaces of the cerebral hemispheres
132
principal site of absorption of CSF
into the venous circulation through the arachnoid vili, which projects into the dural sinuses, primarily the superior sagittal sinus, and in the ependymal lining of the ventricles
133
mitochondrial enzyme deficiencies associated with Leigh disease include ____ which results in elevated blood CSF and CNS lactate, and pyruvate levels
pyruvate dehydrogenase complex, pyruvate carboxylase and electron transport chain
134
type of hydrocephalus that refers to an obstruction occurring within the ventricular system that prevents CSF from exiting the ventricles
noncommunicating hydrocephalus
135
type of hydrocephalus wherein the level of obstruction is beyond the ventricular system, located instead within the subarachnoid space. CSF is able to exit the ventricular system but fails to undergo normal respiration by the arachnoid villi
communicating hydrocephalus
136
in assessing for the presence of hydrocephalus, specific attention should be directed to the
third ventricle and the temporal ventricular horns
137
characteristic finding for hydrocephalus
convex bowing of the lateral walls and inferior recesses of the third ventricle
138
why is third ventricle and temporal ventricular horns are particularly helpful in making the distinction between hydrocephalus and ex vacuo ventriculomegaly
both of these ventricular spaces are surrounded by tissue that is not typically subject to significant atrophy. third ventricle is surrounded by thalamus and there is relative paucity of white matter within the temporal lobes
139
most freq cause of acute hydrocephalus
subarachnoid hemorrhage and meningitis
140
these congenital lesions may form across the cerebral aqueduct, resulting in aqueductal stenosis
benign congenital webs
141
these congenital conditions are believed to represent adhesions occurring during CNS development, at the outlet foramina of the fourth ventricle and posterior fossa
Chiari and Dandy-walker malformations
142
diagnosis of aqueductal stenosis is achieved by
check the normal pulsatile flow void in routine axial and sagittal MRI images
143
chronic, low-level form of hydrocephalus. clinical triad is dementia, gait disturbance and urinary incontinence. In this condition, the CSF pressure is within normal limits, but a slight gradient exists between the ventricular system and the subarachnoid space because of an incomplete subarachnoid hemorrhage or meningeal infection. result is diffuse ventriculomegaly that is out of proportion to the degree of sulcal prominence
normal pressure hydrocphalus
144
most common neurodegenerative disease and the most common cause of dementia, histopathology of the disease is characterized by two structures in the brain: neuritic plaques and neurofibrillary tangles
Alzheimer disease
145
component of Alzheimer disease composed of tortuous neuritic processes surrounding a central amyloid core, which consists primarily of small peptide known as V-amyloid, derived froma larger amyloid precursor protein
neuritic plaques
146
component of Alzheimer disease that contain abnormal tau protein that is associated with microtubulues.
neurofibrillary tangles
147
neuroimaging of patients with AD demonstrates
diffuse atrophy, with a predilection for the hippocampal formation, temporal lobes, and parietotemporal cortices
148
useful findings in discriminating AD from normal age-related atrophy
enlargement of the temporal horns, suprasellar cisterns and Sylvian fissures
149
risk factors in AD include
advanced age and apolipoprotein E e4 allele carrier status
150
most common basal ganglia disorder and one of the leading causes of neurologic disability in individuals older than age 60. disease is characterized clinically by tremor, muscular rigidity and loss of postural reflex. about 25% of these patients develop dementia
Parkinson disease
151
results from a deficiency of the neurotransmitter dopamine caused by the dysfunction of the dopaminergic neuronal system, specifically the pars compacta of the substantia nigra. loss of these nerve cells results in a decreased concentration of the endogeneous striatal dopamine, and after approximately 80% of these cells die, the patient begins to develop symptoms
Parkinsonism
152
True or false: MRI is relatively insensitive in the detection of the loss of pars compacta of the substantia nigra
true
153
MRI may occasionally these findings in parkinson disease
thinning of pars compacta thru loss of high SI band between pars reticularis and red nuclei. pars compacta is sandwiched between pars reticulata anteriorly and red nucleus posteriorly
154
more sensitive imaging tool for the study of diseases of the dopaminergic system
PET, specifically 18F- labelled PET ligands have been developed for imaging postsynaptic dopamine D1 and D2 receptor system. with 18F-levodopa (DOPA), parkinsion patients show a characteristic deficit in putaminal DOPA uptake
155
idiopathic parkinson disease is referred to as ____ and affects 2 to 3 % of the population at some time dring their life
paralysis agitans
156
degenerative diseases of extrapyramidal nuclei include
Huntington disease and Wilson disease
157
this is a progressive hereditary disorder that appears in the fourth and fifth decades of life. this is characterized by movement disoder (typically choreoathetosis), dementia and emotional disturbance. It is inherited in autosomal dominant pattern with complete penetrance
Huntington disease
158
imaging findings in Huntington disease
diffuse cortical atrophy, caudate nucleus and putamen are most severely affected. atrophy of the caudate nucleus results in characteristic enlargement of the frontal horns, which take on a heart-shaped configuration
159
involvement of the gray structures in huntington disease results in this movement disorder ______, with typical onset in the 5th decade of life
choreoathetosis
160
also known as the hepatolenticular degeneration, as an inborn error of copper metabolism that is associated with hepatic cirrhosis and degenerative changes of the basal ganglia. A deficiency of ceruloplasmin results in deposition of toxic levels of copper in various organs
Wilson disease
161
in this degenerative disease, patients present with varied neurologic and psychiatric findings, including dystonia, tremor, and rigidity. Kayser-Fleischer ring, an intracorneal deposit of copper is virtually diagnostic of the disease
Wilson disease
162
MRI findings of Wilson disease
diffuse atrophy, with signal abnormalities involving the deep gray matter nuclei and deep white matter
163
these toxins may result in signal abnormalities of the basal ganglia, characteristically the globus pallidus and putamen, respectively
carbon monoxide and methanol poisoning
164
these infectious conditions may present with areas of signal abnormality within the basal ganglia, showing High SI on T1, associated with hepatic dysfunction, such as hepatic encephalopathy as well as hyperalimentation
West nile virus (via mosquito) and Creutzfeldt- Jakob disease (via consumption of infected beef products)
165
iron deposition within the globus pallidus
Hallervorden-Spatz diease
