IDS/DEMY Flashcards
Toxoplasmosis, rubella, CMV, and HIV all cause _______
parenchymal calcifications
__________ causes periventricular cysts, clefts, schizencephaly, and migrational defects
CMV
_______ and _____ cause lobar destruction and encephalomalacia
Rubella and herpes simplex virus (HSV)
Congenital syphilis is relatively rare but when it occurs, it causes _________
basilar meningitis
_______ should be considered in newborns and infants with microcephaly, parenchymal calcifications, chorioretinitis, and intrauterine growth restriction.
TORCH infections
Early gestational __________infection causes germinal zone necrosis with subependymal dystrophic calcifications
CMV
Imaging features of congenital ______include microcephaly with ventriculomegaly, intracranial calcifications, white matter disease, and neuronal migration disorders. As a general rule, the earlier the infection, the more severe the findings.
CMV
NECT scans show extensive parenchymal calcifications that are predominantly cortical and subcortical . MR scans show multiple subcortical cysts and moderate to severe ventriculomegaly.
Congenital Toxo
The most characteristic gross finding is generalized brain volume loss with symmetric enlargement of the ventricles and subarachnoid spaces. Multiple foci of microglia, macrophages, and multinucleated giant cells containing viral particles are typical. Patchy myelin pallor and vacuolization are common
Congenital (Perinatal) HIV
MC MRI finding of Congenital HIV
The most striking and consistent finding is atrophy, particularly in the frontal lobes. Bilaterally symmetric basal ganglia calcifications are common
3 patterns of neonatal HSV
(1) skin, eye, and mouth disease, (2) encephalitis, and (3) disseminated disease with or without CNS disease
MRI findings of Neonatal HSV
Hyperintensity in the cortex, subcortical white matter, and basal ganglia is typical. Hemorrhagic foci are uncommon in early stages but may develop later and are best seen on T2* (GRE, SWI) sequences.
_________is key to the diagnosis of congenital HSV encephalitis
DWI
In some cases, HSV causes watershed distribution ischemic injury in areas remote from the primary herpetic lesions and may be difficult to distinguish from ______
hypoxicischemic injury (HII)
Imaging findings for congenital rubella
parenchymal calcifications on NECT scans to multiple foci of T2/FLAIR hyperintensity and volume loss with mildly enlarged ventricles and sulci
Imaging findings for congenital syphilis
The most common imaging findings in CS are hydrocephalus and meningitis with leptomeningeal enhancement
CAUSES OF HYPERINTENSE CSF ON FLAIR
Common Blood o Subarachnoid hemorrhage Infection o Meningitis Artifact o Susceptibility o Flow Tumor o CSF metastases
Although myriad organisms can cause abscess formation, the most common agents in immunocompetent adults are ____________, ________ and ________. _______ is a common agent in neonates
Streptococcus species, Staphylococcus aureus, and pneumococci. Citrobacter
Proinflammatory molecules such as _______ and ___________ induce various cell adhesion molecules (CAMs) that facilitate extravasation of peripheral immune cells and promote abscess development
tumor necrosis fac-tor-α (TNF-α) and interleukin-1-β (IL1-β)
In Abscess formation __________ is hypo- to isointense on T1WI and hyperintense on T2/FLAIR. T2* GRE may show punctate “blooming” hemorrhagic foci. Patchy enhancement may or may not be present. DWI shows diffusion restriction
Early cerebritis
DWI and MRS of Late cerebritis
Late cerebritis restricts strongly on DWI. MRS shows cytosolic amino acids (0.9 ppm), lactate (1.3 ppm), and acetate (1.9 ppm) in the necrotic core
What is seen in early abscess capsule formation
A “double rim” sign demonstrating two concentric rims, the outer hypointense and the inner hyperintense relative to cavity contents, is seen in 75% of cases (
Classic CT findings of ventriculitis
Ventriculomegaly with a debris level in the dependent part of the occipital horns together with periventricular hypodensity is the classic finding on NECT scans
FLAIR and DWI findings of ventriculitis
A “halo” of periventricular hyperintensity is usually present on both T2WI and FLAIR scans. DWI shows diffusion restriction of the layered debris
MRI findings of subdural empyema
T1 scans show an extraaxial collection that is mildly hyperintense relative to CSF. SDEs are typically crescentic and lie over the cerebral hemisphere. The extracerebral space is widened and the underlying sulci are compressed by the collection. SDEs often extend into the interhemispheric fissure but do not cross the midline.
For Cerebral Empyema Bone CT: Look for __________ ________ is focal, biconvex, can cross midline SDE is crescentic, covers hemisphere, may extend into interhemispheric fissure SDEs_______ on DWI; EDEs variable
sinus, ear infection EDE restrict strongly
In HSV Enceph ________ is the most sensitive sequence and may be positive before signal changes are apparent on either T1- or T2WI
FLAIR
In Varicella enceph, Children may develop _________ with patchy foci of T2/FLAIR hyperintensity. VZV________ causes multifocal cortical, basal ganglia, and deep white matter hyperintensities
multifocal leukoencephalopathy vasculopathy with stroke
Uncontrolled proliferation of EBV-infected B cells results in ________
post-transplant lymphoproliferative disease (PTLD)
EBV has a predilection for _________. Bilateral diffuse T2/FLAIR hyperintensities in the basal ganglia and thalami are common
deep gray nuclei
________ is a more severe, life-threatening form of IAE characterized by high fever, seizures, and rapid clinical deterioration within two or three days after symptom onset. The disease is often fatal. Most cases occur in children or young adults
Acute necrotizing encephalopathy (ANE)
_________is also called chronic focal (localized) encephalitis. RE is a rare progressive chronic encephalitis characterized by drug-resistant epilepsy, progressive hemiparesis, and mental impairment.
Rasmussen encephalitis (RE)
Imaging of Rasmusen
The disease is characterized by unilateral progressive cortical atrophy. Basal ganglia atrophy is seen in the majority of cases. MRS findings are nonspecific with
Describe the features of Congenital CMV
Congenital CMV is shown with periventricular parenchymal calcifications , damaged white matter
, dysplastic cortex
What is your dx?
NECT in a newborn with CMV shows microcephaly, large ventricles, shallow sylvian fissures ,
striking periventricular Ca
What is shown in this pt with CMV?
Coronal T2WI in the same patient shows periventricular WM hyperintensities , anterior temporal
lobe cysts
What is your dx?
Axial NECT scan through the cerebral convexities shows the peripheral nature of the calcifications in this child with congenital toxoplasmosis. The linear “tram-track” calcification pattern described in some cases is nicely demonstrated here .
Axial T2WI in the same child with congenital toxoplasmosis
shows normal sulcation and gyration without evidence of the cortical malformations typically seen with
CMV
What is your dx?
Axial T2WI MR in an 11 year old demonstrates late manifestations of congenital HIV. Note prominent
ventricles and sulci as well as multifocal white matter hyperintensities. 12-6B. Submentovertex view of an
MRA obtained in the same patient shows striking fusiform arteriopathy in both middle cerebral arteries
What is your dx?
DWI in a 2-week-old infant with seizures, bulging fontanelles
DWI in a 2-week-old infant with seizures, bulging fontanelles demonstrates extensive foci of
restricted diffusion in both hemispheres . HSV2 encephalitis.
What is your dx?
T2WI in the same infant obtained 1 month later shows dramatic interval changes of multicystic encephalomalacia with blood-fluid levels .
Note extensive areas of ribbonlike T2 shortening in the
cortex secondary to hemorrhage. 12-9D. More cephalad scan in the same patient illustrates extensive cystic encephalomalacia underlying more foci of gyral T2 shortening
This case illustrates both early
and late changes of congenital HSV.
What is shown in this pt with congenital rubella
T2WI in the same patient shows striking delayed myelination, symmetric periventricular
hyperintensities
What is shown in this pt with LCM
NECT in an infant with congenital lymphocytic choriomeningitis shows scattered parenchymal ,
basal ganglia calcifications
What is your dx?
T1 C+ FS scan in the same patient shows diffuse, intense enhancement of the basal cisterns, sulci
. 12-20C. Scan through the corona radiata in the same patient shows that the enhancement covers the
pial surfaces of the gyri and fills the convexity sulci . Classic findings of pyogenic meningitis
What is shown in this pt with abscess?
T2WI in the same patient shows a mixed iso- and hyperintense mass .DWI shows mild restricted diffusion at the periphery and center of the lesion, not what would be expected for a
late acute cerebral infarct.
What stage of abscess formation?
T1 C+ scan shows a tiny enhancing focus in the center of the largely nonenhancing mass. The
enhancement corresponds to the center of the diffusion restriction noted on DWI image. 12-28F. Slightly
delayed coronal T1 C+ scan shows the enhancing focus as well as a faint rim of peripheral enhancement
around the lesion . Typical imaging findings of early cerebritis
DWI and MRS findings of abscess?
DWI shows that the center of the lesion restricts strongly . 12-29F. MRS of the cavity TR 2,000 TE 35. Amino acids (valine, leucine, isoleucine) at 0.9 ppm , acetate at 1.9 ppm , lactate at 1.3 ppm , and succinate at 2.4 ppm (double straight arrows). Imaging findings are those of an abscess at the late cerebritis/early capsule stage.
Describe the DWI and ADC
The mass restricts strongly on DWI .
ADC shows that the mass is very hypointense compared to normal brain parenchyma, confirming that the hyperintensity seen on DWI is true diffusion restriction. The hyperintensity surrounding the mass is edema
What is your dx?
Autopsy case of IVRBA shows ependymal infection , choroid plexitis , pus adhering to
ventricular walls
Dsecribe findings of abscess with rupture
Axial NECT in a 28-year-old female drug abuser with severe headache shows enlarged ventricles with indistinct (“blurred”) margins, possible fluid-debris levels in both occipital horns .
12-33B. FLAIR scan in the same patient shows transependymal CSF migration , thickened hyperintense ependyma with distinct fluid-debris levels
What is your dx?
Axial NECT in a 28-year-old female drug abuser with severe headache
Sagittal T2WI in a child with frontal sinusitis causing scalp cellulitis , epidural empyema
What is the dx?
T1 C+ FS scan shows that the EDE crosses the midline, displacing the thickened dura posteriorly . The SDE is seen positioned between the thickened dura on the outside and the enhancing arachnoid on the inside.
DWI shows that both the EDE and the SDE restrict strongly and equally. Note the small subdural empyema in the interhemispheric fissure . Combined EDEs and SDEs occur in 15% of cases.
What are the lobes involved in HSV?
Coronal graphic shows the classic features of herpes encephalitis with bilateral but asymmetric
involvement of the limbic system. There is inflammation involving the temporal lobes, cingulate gyri, and
insular cortices
Describe the FLAIR and DWI
68-year-old man presented to the emergency department with viral prodrome, confusion. Initial
NECT scan (not shown) was negative. MR was obtained emergently.
Some motion artifact is present, but FLAIR scan shows hyperintensity in both insular cortices . 12-46B. DWI shows marked diffusion
restriction in both insular cortices . Somewhat less striking hyperintensity is seen in both anterior
temporal lobes
What is the dx?
DWI demonstrates restricted diffusion in the left temporal lobe . The right temporal lobe appears normal. 12-48F. T1 C+ scan shows no evidence of enhancement. HHV-6 encephalopathy was subsequently documented. Exclusive involvement of the mesial temporal lobe without evidence for abnormalities outside the hippocampus and amygdala helps differentiate HHV-6 encephalopathy from HSE.
What is the dx?
VZV vasculitis with basal ganglia infarct in a 4-year-old girl. NECT and FLAIR scans show putaminal infarct that restricts as shown on DWI and ADC .
What is the dx?
Typical findings of WNV encephalitis include bilateral but asymmetric nonenhancing lesions in the
basal ganglia and midbrain . DWI may demonstrate restriction
What is the dx?
16-year-old male with deteriorating school
performance and behavioral changes shows gross atrophy with bifrontal and bioccipital hypointensities .
CSF was positive for measles antibodies.
Autopsy of SSPE shows grossly enlarged ventricles and sulci with striking volume loss in the basal ganglia and cerebral white matter. In the occipital poles, the white matter is so thin the ventricles almost contact the cortical gray matter.12-58. Axial T1WI in a
23 yo with medically refractory epilepsy
Axial FLAIR in a 23 yo with medically refractory epilepsy secondary to RE shows left frontotemporal lobe volume loss with left lateral ventricle, sulcal enlargement. Note hyperintensity in the WM, basal
ganglia, insula, cortex
Imaging features of Tuberculoma
o Iso-/hyperdense parenchymal mass(es)
o Round, lobulated > irregular margins
o Variable edema
o Punctate, solid, or ring enhancement
o May cause focal enhancing dural mass
o Chronic, healed may calcify
MRI findings of Tuberculoma
Tuberculoma
o Hypo-/isointense with brain on T1WI
o Most are hypointense on T2WI
o Rim enhancement
o Rare = dural-based enhancing mass
o Large lipid peak on MRS
CNS fungal infections are also called cerebral mycosis. A focal “fungus ball” is also called a_______ or ______
mycetoma or fungal granuloma.
Aside from ____________most fungal infections are initially acquired by inhaling fungal spores in contaminated dust and soil.
C. albicans (a normal constituent of human gut flora),
______occurs in areas with low rainfall and high summer temperatures (e.g., Mexico, southwestern United States, some parts of South America) whereas _______ and ___________occur in watershed areas with moist air and damp, rotting wood (e.g., Africa, around major lakes and river valleys in North America
Coccidioidomycosis
histoplasmosis and blastomycosis
Sinonasal disease with intracranial extension (rhinocerebral
disease) is the most common pattern of ______ and _______
Aspergillus and Mucor CNS infection
CNS mycoses have four basic pathologic manifestations:
Diffuse meningeal disease (most common),
solitary or multiple focal parenchymal lesions (common),
disseminated nonfocal parenchymal disease (rare),
and focal durabased masses (rarest
______in the paranasal sinuses is usually seen as a single opacified hyperdense sinus that contains fine round to linear calcifications
Mycetoma
Fungal meningitis appears as _______T1WI. Parenchymal lesions are typically hypointense on T1WI but
demonstrate T1 shortening if subacute hemorrhage is present (13-23). Irregular walls with nonenhancing
projections into the cavity are typical.
“dirty” CSF on
________scans in patients with fungal cerebritis show bilateral but asymmetric cortical/subcortical and basal
ganglia hyperintensity
. Focal lesions (mycetomas) show high signal foci that typically have a peripheral hypointense rim, surrounded by vasogenic edema. T2* scans may show “blooming” foci caused by________ and _______
T2/FLAIR
hemorrhages or calcification
MRS findings of CNS Fungal infection
MRS shows mildly elevated Cho and decreased NAA. A lactate peak is seen in 90% of cases, while lipid and amino
acids are identified in approximately 50%.
________s the most common parasitic infection in the world, and CNS lesions eventually develop in 60-90% of
patients with cysticercosis
Cysticercosis
Imaging features of Neurocystersorcosis
o _______Cyst with “dot” (scolex), no edema, no enhancement
o ________Ring enhancement, edema striking
o ________Faint rim enhancement, edema decreased
o __________: CT Ca++, MR “black dots”
Vesicular:
Colloidal vesicular:
Granular nodular:
Nodular calcified
Two basic types of CNS amebic infection occur:
Primary amebic meningoencephalitis (PAM) and granulomatous amebic encephalitis (GAE).
Findings of Primary amebic encephalitis
leptomeningitis with sulcal obliteration and enhancement, especially along the perimesencephalic cisterns. Multifocal parenchymal lesions with involvement of posterior fossa structures,
Typical imaging findings of ___________are single or multiple conglomerated heterogeneous lesion(s) with
edema and mass effect. A central linear enhancement surrounded by multiple punctate nodules (an “arborized”
appearance) on T1 C+ MR
neuroschistosomiasis
TRIAD OF LYME
aseptic meningitis, cranial neuritis, and radiculoneuritis
What are the findings of Lyme Disease on MRI
The most common MR finding is multiple small (two to eight millimeters) subcortical and periventricular white matter hyperintensities on T2/FLAIR .
These are identified in approximately half of all patients with LNB. Large “tumefactive” lesions are uncommon.
______________may cause a vasculopathy with lacunar or territorial infarcts that are indistinguishable from thromboembolic strokes
Meningovascular syphilis
Syphilitic _____________are hypo- or mixed-density lesions on NECT that enhance intensely on CECT. A ring-like or diffuse enhancement pattern is typical.
gummata
MR shows the gummata are hypointense on T1 and heterogeneously hyperintense on T2WI. Marked enhancement on T1 C+ is seen, and a _________is present in one-third of cases
dural “tail”
What is shown in this pt with TBM
Axial section through the suprasellar cistern in another autopsied case of TBM shows thick exudate filling the suprasellar cistern and coating the pons. Note the extremely small diameter of the supraclinoid ICAs due to TB vasculitis.
Surgically resected TB gumma shows the solid “cheesy” appearance of a caseating granuloma.
Describe CSF findings of pt with TBM
TBM with “dirty” CSF , hydrocephalus , basilar meningeal enhancement , restricted diffusion.
Describe the hypointensities
Axial T2WI shows hypointense caseating tuberculomas , edema . Central liquefaction is
hyperintense
MRS of TBM
MRS with TE = 35 msec shows decreased NAA, prominent lipid lactate peak
Describe what is shown
Gross autopsy case shows TB as a focal dural mass . Appearance is indistinguishable from that of meningioma.
13-12A. CECT scan in a case of proven dura-based TB inflammatory pseudotumor shows extensive “en plaque” enhancing right frontotemporal mass
What is shown?
Corona-like arrays of Aspergillus penetrate the wall of a leptomeningeal blood vessel
What is the dx?
Axial NECT scan in an immunocompetent patient shows a hypodense mass with a faint rim of hyperdensity surrounded by significant edema .
13-18B. CECT scan in the same patient shows an irregular, crenelated enhancing rim with edema, adjacent ventriculitis . Aspergilloma was found at surgery.
What could be the dx?
Aspergillus abscesses in an immunosuppressed patient. Axial T1WI shows punctate and ring-like hyperintense foci with “blooming” on T2* .
Nodular and rim enhancement is seen on T1 C+ FS . Most of the lesions restrict on DWI
What is the dx
Axial T2WI FS shows normal right cavernous ICA “flow void” with left cavernous sinus mass, occluded ICA . 13-28C.
T1 C+ FS scan in the same patient shows the left cavernous sinus invasion ,occluded carotid artery
What figure is shown?
Low-power photomicrograph of cysticercus shows the invaginated scolex lying within the thinwalled cyst , also known as the bladder.
Close-up view shows a nodular calcified NCC cyst . Note the lack of inflammation and lack of mass effect.
What is shown?
T2WI shows disseminated vesicular NCC with “salt and pepper brain” appearance. Innumerable tiny hyperintense cysticerci with scolices (seen as small black “dots” inside the cysts) are present. Perilesional edema is absent.
What stages of NCC are shown?
T2* GRE scan shows multiple “blooming black dots” characteristic of nodular calcified NCC. 13- 36D. T1 C+ FS scan shows faint ring-like and nodular enhancement of healing granular nodular NCC cysts. “Shaggy” enhancement with adjacent edema is characteristic of degenerating larvae in the colloidal vesicular stage. Multiple lesions in different stages of evolution are characteristic of NCC
What is the dx?
“Racemose” NCC. Multiple small cysts without visible scolices fill the suprasellar cistern . Note
hydrocephalus, meningeal reaction with moderate rim enhancement around the “bunch of grapes” cysts
What is the dx
Autopsy case shows brain after the removal of a huge unilocular hydatid cyst. Note the welldemarcated
border between the cyst cavity and the brain. There is no surrounding edema, and the mass
effect relative to the size of the cyst is minimal. 13-39B. Photograph of the external cyst wall with cut
view of the cyst shows the typical thin wall of a classic hydatid cyst
What is the dx?
Axial T1WI shows a unilocular hydatid cyst . Mass effect relative to the overall cyst size is only
moderate. 13-40B. T2WI in the same patient nicely demonstrates the typical threelayered cyst wall
What is the dx?
Classic “slate gray” edematous cortex of cerebral malaria (left) compared to normal brain (right)
What is the dx
In cerebral malaria, parasites convert metabolized hemoglobin to hemozoin (“malarial pigment”),
seen here as tiny black “dots” in sequestered red blood cells . (Courtesy B. K. DeMasters, MD.) 13-52.
Scans in a patient with malaria show T2 basal ganglia hyperintensities that “bloom” on T2* GRE ,
restrict on DWI
What CN are affected?
T1 C+ FS scans in a patient with Lyme disease and multiple cranial nerve palsies show enhancement
of the right fifth and sixth CNs as well as both oculomotor nerves
MRI Image of HIV Enceph
Volume loss with ↑ sulci, ventricles
T2/FLAIR “hazy” WM symmetric hyperintensity
o Spares subcortical U-fibers
No mass effect
Usually no enhancement
o Possible exception = acute fulminant HIVE
MC Imaging findings on Toxoplasmosis
The most common finding on NECT scan is multiple ill-defined hypodense lesions in the basal ganglia
or thalamus with moderate to marked peripheral edema.
T or F
In patients with counts under 50, enhancement is absent
or faint on Congenital Toxo
T
Disseminated toxoplasmosis encephalitis, also called ________________, produces multifocal T2
hyperintensities in the basal ganglia and subcortical white matter. Enhancement may be absent or minimal despite
fulminant disease
microglial nodule encephalitis
What are the phases of PML Infection
Three phases in the development of PML have been identified.
The first phase is the primary but clinically inapparent infection.
In the second phase, the virus persists as a latent peripheral infection, primarily in the kidneys, bone marrow, and lymphoid tissue.
The third phase is that of reactivation and dissemination with hematogenous spread to the CNS.
MRI findings of PML
Multifocal WM lesions
o Bilateral but asymmetric
o Involve subcortical U-fibers
o Spare cortex
Usually no mass, no enhancement (unless iPML)
____________occurs when antiretroviral therapy reveals a subclinical, previously undiagnosed opportunistic
infection. Immune restoration leads to an immune response against a living pathogen. Here brain parenchyma is
damaged by both the replicating pathogen and the incited immune response
“Unmasking” IRIS
___________occurs when a patient who has been successfully treated for a recent opportunistic infection
unexpectedly deteriorates after initiation of antiretroviral therapy. Here there is no newly acquired or reactivated
infection. The recovering immune response targets persistent pathogen-derived antigens or self-antigens and
causes tissue damage
“Paradoxical” IRIS
Natalizumab-related PML is managed by discontinuation of the drug and instituting
_________
plasmapheresis/immunoadsorption (PLEX/IA).
Imaging of HIV associated lymphoma
Imaging
o Hemorrhage, necrosis common
o Supratentorial (90%)
o Basal ganglia, deep WM (often crosses corpus callosum)
o Often ring-enhancing
o ↑ rCBV
What is shown?
Coronal autopsy of HIVE shows generalized volume loss with enlargement of the lateral ventricles,
sylvian fissures. “Hazy,” poorly defined abnormalities are present in the WM but spare the subcortical
U-fibers
What is shown?
shows striking enhancement around the deep
medullary veins of both hemispheres . 14-5D. T1 C+ scan through the corona radiata shows striking
linear and punctate enhancement suggesting acute inflammatory changes around the medullary veins.
Findings probably represent acute demyelination in fulminant HIVE.
dx?
Submentovertex 2D TOF MRA in another child with HIV/AIDS and HIV vasculopathy shows marked
fusiform enlargement of both middle cerebral arteries and less dramatic enlargement of the left ACA
What is shown?
Axial T1 C+ FS through the third ventricle shows multiple punctate enhancing lesions . 14-15D.
Axial T1 C+ FS shows that the hyperintense layer seen on the T2WI enhances whereas the center and
periphery of the lesion remain unenhanced. Multifocal toxoplasmosis.
dx?
demonstrates that the lentiform nuclei and the heads of
both caudate nuclei are grossly expanded by innumerable hyperintense cysts characteristic of cryptococcal gelatinous pseudocysts
What is shown?
Close-up coronal view of autopsied brain from a patient with severe advanced PML shows coalescent,
spongy-appearing, demyelinated foci along the cortical gray-white matter junction extending into the
subcortical and deep WM
What structures are shown?
Dark infected oligodendrocytes are concentrated at the edge of the pink-appearing
demyelinated foci in this classic microscopic image
`What is the dx?
MR in a clinically deteriorating 46-year-old HIV-positive patient with a CD4 count < 10 shows a
confluent nonenhancing left occipital lesion that crosses the corpus callosum . CSF was PCR-positive
for JCV.
What are ddx?
Axial T1 C+ FS scan shows an irregular rim of enhancement around the central necrotic area. Note eccentric enhancing nodule within the necrotic mass. 14-40D. Coronal T1 C+ shows the “eccentric target” appearance of the lesion. Because of the “target” sign, the imaging diagnosis was toxoplasmosis (even though a solitary lesion is statistically more likely to be PCNSL). The patient did not respond to antitoxo therapy. Biopsy showed diffuse large B-cell lymphoma
Microscopic features of MS
Active: Hypercellular with robust inflammation, myelin destruction
Chronic active: Inflammation around borders
Chronic silent: Glial scarring, no active inflammation
The first attack of MS (most commonly optic neuritis, transverse myelitis, or a brainstem syndrome) is known as a
_________
clinically isolated syndrome
Most MS plaques are hypo- or isointense on T1WI. The hypointensity (“black holes”) correlates with______
axonal destruction.
Findings of MS in T2 FLAIR
T2WI shows multiple hyperintense linear, round, or ovoid lesions surrounding the medullary veins that
radiate centripetally away from the lateral ventricles. Larger lesions often demonstrate a very hyperintense center
surrounded by a slightly less hyperintense peripheral area and variable amounts of perilesional edema
MS plaques often assume a distinct triangular shape with the base adjacent to the ventricle on sagittal FLAIR or T2WI images. One of the earliest findings is alternating areas of linear hyperintensity along the ependyma on sagittal FLAIR, known as the________ sign
“ependymal ‘dot-dash’” sign
T1 C+. MS plaques demonstrate transient enhancement during the active stage of demyelination. Punctate, nodular, and rim patterns are seen. A prominent incomplete rim (“horseshoe”) of enhancement with the “open” nonenhancing segment facing the cortex can be present , especially in__________
large “tumefactive” lesions
DWI findings of MS
The overwhelming majority of acute plaques show normal or increased diffusivity, not restricted diffusion.
While a few acute MS plaques can demonstrate restriction on DWI, such an appearance is atypical and should not
be considered a reliable biomarker of active plaques
MRS may allow early distinction between relapsing-remitting and secondary-progressive MS. Secondary progressive MS shows _______in normal-appearing gray matter consistent with axonal/neuronal loss or dysfunction
decreased NAA
Rare acute fulminate MS variant
o Rapid neurologic deterioration
o Monophasic, relentless progression
o Death usually within 1 year
Usually young adults
What disease?
MARBURG DISEASE
MRI findings of Marburg dse
Imaging shows diffusely disseminated disease
o Large cavitating lesions
o Incomplete (“open”) enhancing rim
o Multiple other patchy enhancing foci
__________—also known as myelinoclastic diffuse sclerosis—is a rare disorder characterized by one or more inflammatory demyelinating white matter plaques. It is typically a disease of childhood and young adults. Median age at presentation is 18 years, with a slight female predominance
Schilder disease (SD)
MRI findings for Schilders
Imaging shows a subcortical hypodense lesion on NECT scans. MR shows a hypointense lesion on T1WI that
is hyperintense on T2/FLAIR. Rim enhancement—often the incomplete or “open ring” pattern—is seen during the
acute inflammatory stage
The pathologic hallmark of ________is a
peculiar pattern of concentric rings that resembles a tree trunk or onion bulb.
Large demyelinated plaques with
alternating rims of myelin preservation and destruction give the lesion its characteristic appearance
Balo concentric sclerosis
Recent studies suggest that the therapeutic options in NMO should be___________
rather than immunomodulatory drug
immunosuppressive
What is the NMO diagnostic criteria
Required
Optic neuritis
Acute myelitis
Hyperintense, enhancing cord lesion ≥ 3 segments
Plus Two or More Supportive Criteria
Disease-onset MR imaging nondiagnostic for MS
Contiguous spinal cord lesions on MR ≥ 3 vertebral segments
NMO-IgG seropositivity
What is SUSAC syndrome
Susac syndrome (SS) is also known as retinocochleocerebral vasculopathy, RED-M (for retinopathy, encephalopathy,
and deafness-associated microangiopathy), and SICRET (small infarcts of cochlear, retinal, and encephalic tissue
Classic presentation of Susac’s disease
The classic clinical triad in SS consists of acute or subacute encephalopathy, sensorineural hearing
loss, and branch retinal artery occlusions
MRI findings of Susac
Sagittal T1WI in patients with chronic SS may show typical “punched-out” hypointense lesions in the middle layers of the corpus callosum. T2/FLAIR shows multiple periventricular and deep white matter
hyperintensities in over 90% of cases
Acute disseminated encephalomyelitis (ADEM) is a post-infection, post-immunization disorder that is also called
_____________.Once considered a purely monophasic illness, recurrent and multiphasic forms
of ADEM are now recognized.
parainfectious encephalomyelitis.
Types of ADEM
o Monophasic ADEM: Most common
o Recurrent ADEM: Second episode, same site
o Multiphasic ADEM: Multiple episodes, different sites
MRI findings of ADEM
Multifocal T2/FLAIR hyperintensities
o Bilateral but asymmetric WM lesions
o Subcortical, periventricular
o Small round/ovoid to flocculent “cotton balls”
o Basal ganglia, posterior fossa, cranial nerves often involved
Other names for
Acute hemorrhagic leukoencephalitis (AHLE)
Acute hemorrhagic leukoencephalitis (AHLE) is also known as acute hemorrhagic leukoencephalopathy, acute
hemorrhagic encephalomyelitis (AHEM), and Weston Hurst disease.
Findings of AHLE in MRI
Multifocal punctate and linear “blooming” hypointensities in the corpus callosum that extend through the full thickness of the hemispheric white matter to the subcortical U-fibers are typical findings on T2*. Striking sparing of the overlying cortex is common. Additional lesions are frequently present in the basal ganglia, midbrain, pons, and
cerebellum.
What is shown?
Close-up view of autopsied MS shows several cavitated, chronic inactive lesions with their welldefined margins and scarred excavated depressed centers as well as 2 grayish chronic active lesions
Luxol fast blue myelin stain shows relatively normal “robin’s-egg blue” tissue on the right, pinkish demyelinated tissue on the left in classic MS
What findings of MS is shown?
(Not Dawson)
Sagittal T1WI in a 19-year-old woman with longstanding MS shows findings of chronic “burned out”
disease. Volume loss with multiple hypointense ovoid and triangular lesions in the deep periventricular WM
is present. 15-8B. Axial T1WI shows the ill-defined hyperintense rims surrounding the plaques ,
giving the distinct “lesion-within-a-lesion” appearance.
Describe the orientation of MS plaques
FLAIR shows the characteristic triangle configuration of typical deep white matter MS plaques seen
in the sagittal plane. The broad bases of the triangles are oriented toward the ventricular surface with
the apices pointing toward the cortex. 15-8D. T2WI shows the ovoid perivenular plaques that are
oriented perpendicular to the lateral ventricles as seen in the axial plane
What sign is shown?
Sagittal FLAIR shows small triangle-shaped hyperintensities at the callososeptal interface . Note alternating areas of hyper- and isointensity along the undersurface of the corpus callosum , the “dot-dash” sign of early MS.
15-10D. Axial T1 C+ FS shows multiple enhancing lesions in the posterior fossa , including an incomplete rim-enhancing lesion and an infiltrating lesion at the root entry zone of the left trigeminal nerve
What type of MS?
Series of images demonstrates “tumefactive” MS. Axial T1WI shows large heterogeneously
hypointense lesions in both cerebral hemispheres with significant perilesional edema . 15-12B.
T2WI shows that the lesions are very hyperintense and surrounded by a thin hypointense rim and
perilesional edema
DWI findings for MS
The hypointense rims of the lesion show striking but incomplete ring enhancement . 15-12D.
DWI shows that the enhancing rims restrict moderately
What MS variant?
T1 C+ FS through the ventricles shows the necrotic, cavitating, acutely enhancing right parietal
“tumefactive” mass . Other enhancing foci are present . 15-16D. Coronal T1 C+ scan shows
extension around the left ventricle in addition to other enhancing foci . Marburg variant of MS.
What is shown?
Acute Balo concentric sclerosis is illustrated by the fluffy-appearing confluent WM lesions on FLAIR . The lesions restrict on DWI , show concentric laminated (“onion bulb”) enhancement . 15- 19B. Follow-up scans after acute symptoms subsided show alternating rings of isoand hyperintensity on T1 scans and iso-/hyperintensity on T2WI . No enhancement is seen on T1 C
What is shown?
Axially sectioned spinal cord in the same case shows cavitating central cord lesions
What is the lesion?
Axial T1 C+ FS in a patient with serologically proven NMO shows optic chiasm enhancement .. Coronal T1 C+ scan in the same patient confirms the optic chiasm enhancement. T2/FLAIR scans (not shown) showed no evidence of other lesions
These are classic findings of what disease?
Classic findings of Susac syndrome with middle callosal “holes” on sagittal T1WI , multifocal ovoid callosal and WM hyperintensities on FLAIR, diffusion restriction on DWI
What type of ADEM is shown?
“Flocculent” ADEM lesions are illustrated in this case. Axial T2WI shows bilateral brachium pontis lesions with a “fluffy” appearance and “fuzzy” margins .
15-28B. Axial T2WI in the same patient shows classic subcortical “fluffy” hyperintensities of ADEM. The cortex overlying the lesions appears intact. Note the right frontal lesion with a very hyperintense center , slightly less hyperintense periphery
What is the dx?
FLAIR scan in a patient of acute “tumefactive” MS shows a large confluent hyperintense mass that exclusively involves the white matter , sparing the cortex . No other lesions were present. 15-30B. T1 C+ FS in the same patient shows partial rim enhancement around the mostly nonenhancing mass . Biopsy disclosed acute demyelinating disease without evidence of neoplasm or infection.
Which vessels are affected?
Multiphasic ADEM is illustrated in this case of a 52-year-old woman who presented with left-sided headache, retroorbital pain, and visual loss. Axial FLAIR scan shows enlarged hyperintense perivenular spaces in the deep cerebral white matter.
15-31B. Axial T1 C+ scan in the same patient shows striking linear enhancement along the deep medullary veins and perivascular spaces
What is the dx?
Coronal autopsy of AHLE shows innumerable bilaterally symmetric petechial WM hemorrhages extending into subcortical U-fibers. Note lesions in corpus callosum . The cortex is completely spared but not the deep gray nuclei
What is the possible diagnosis?
Coronal T1 C+ scan shows enhancing thickened pia . Extensive dura-arachnoid thickening is readily apparent on this image, as is enhancement in the underlying parenchyma . Biopsy disclosed neurosarcoid with brain invasion.
15-43. Photomicrograph of another case shows extensive pial infiltration by noncaseating sarcoid granulomas. Note extension along the penetrating perivascular spaces into the brain parenchyma
What structures are enhanced?
Coronal T2WI with fat saturation in a 50-year-old man with progressive vision loss shows thickened hypointense dura extending along the planum sphenoidale, anterior clinoid processes. Both optic nerves appear compressed .
15-48B. Coronal T1 C+ FS shows striking enhancement . Both optic nerves show abnormal enhancement . Biopsy-proven idiopathic inflammatory pseudotumor without evidence of neoplasm, infection, or noncaseating granulomas
