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),