More imaging yay yatta desu ne

Question 1

Whats CNS Imaging for? and NOT for?

Answer 1

NOT for diagnosis; Neither for excluding Meningitis
- Meningitis diagnosis is by LP

FOR:

• Cx which needs surgical stuff
• • eg abscess; Raised ICP

Question 2

General principles of

• Bacterial
• Viral
• Fungal

Answer 2

Bacterial - think abscesses, meningitis
Viral - encephalitis
Fungal - think Immunocompromised

Question 3

Whats needed to determine safety of LP?

Why LP need check safety?

Answer 3

Ask

• History of CNS infection
• Immunocompromised
• Papilloedema (optic disc swelling)
• • Do CT scan for raised ICP

Cx
Coning: cerebellar tonsils move downward through the foramen magnum possibly causing compression of the lower brainstem and upper cervical spinal cord as they pass through the foramen magnum.

Question 4

If got history of stuffies then how to proceed?

Answer 4

Blood Culture
AB, Dexamethasone,

CT scan
then LP

Question 5

How does abscess and infraction present as on MRI?

and whats the diff between abscess and infraction presentation?

Answer 5

Both have restricted diffusion
- hence DWI is BRIGHT; and ADC is dark

Abscess has REL
infract no REL

Question 6

REL need think what

- and also think more of what

Answer 6

Abscess - nocardia; toxoplasmosis; fungus for IC
Tumor - lymphoma, glioblastoma multiforme

• differentiate by onset of disease
• HIV px w REL need split btw toxoplasmosis and lymphoma

Question 7

Herpes Simplex

- MRI properties?

Answer 7

Bilateral, Symmetrical
Medial frontal lobes
(from lecture notes)

In the immunocompetent adult patient, the pattern is quite typical and manifests as a bilateral asymmetrical involvement of the limbic system, medial temporal lobes, insular cortices and inferolateral frontal lobes. The basal ganglia are typically spared, helping to distinguish it from a middle cerebral artery infarct.
(from google)

Question 8

Strep Pneumonia

- MRI properties?

Answer 8

Micro abscesses
REL
no encephalitis

Question 9

TB

• MRI properties?
• then how?

Answer 9

• Nodular leptomeningeal enhancement in basal systems – typical of TB;
• Check CXR

Question 10

What are the TORCHes

which is the most LITTY

Answer 10

Toxoplasmosis
Others (Zika, Hep B)
Rubella
CMV (most common)
HSV

Question 11

CMV effects

• MRI presentation like 5???
• abit of pathogenesis; others like 5 also

Answer 11

Periventricular ICC
Microcephaly
Cerebral/Cerebellum atrophy
- Gyri v broad, Sulci v shallow
White matter disease (too bright, fluid)
- predominantly in posterior parietal

Anterior Temporal Cyst;

Ventriculomegaly - CMV is neurotropic and replicates in the ependyma, germinal matrix and capillary endothelium

Hearing loss
Chorioretinitis
HSmegaly

Question 12

How to diagnose congenital CMV infection and why need

Answer 12

PCR

- to give ganciclovir to decrease hearing loss;

Question 13

What TORCH infections give ICC on CT and their differing locations

Answer 13

CMV - Periventricular
Zika - periphery
Toxoplasmosis - Basal Ganglia

Question 14

How to differentiate time of CMV infection

• isit better or worse at the start?
• what the diffs

Answer 14

Worse at start

• SEVERE microcephaly
• lissencephaly - smooth brain - form of neuronal migration

2nd trimester:

• polymicrogyria - many small gyri
• schizencephaly - slits/cleft in brain filled w CSF

Otherwise all 3 trimesters have

• ICC
• ventriculomegaly
• WM disease // leukoencephalopathy (leuko means white)

Question 15

Zika presentations

Answer 15

Cortical/Periventricular calcifications
- more of near periphery cos Zika to grey white matter junction while CMV is to ependymal lining
Ventriculomegaly
Cerebral Atrophy
micropthalmia

and others

Craniofacial disproportion
Redundant scalp skin (in occipital region)
Microcephaly + Prominent external occipital protuberance

Question 16

Diff between abscess and tumor in MRI

Answer 16

Tumor no central restricted diffusion hence
in MRI DWI: tumor is black

• some tumors may be Restricted diffusion though hence DWI black as well;

Epidermoid cysts; Meningiomas; Chordomas; Lymphomas; Glial tumors; Abscess

Question 17

Note demyelination also causes REL
- but is perivenular
- OPEN ring enhancement // horse shoe enhancement
also no central RD cos no pyogenic material

Answer 17

okie

Question 18

Neonates CNS infection

• suspect what
• • why suspect that lmao
• flow of infection
• • why

Answer 18

Bacteria

• E. Coli, L.MCG, GBS Strep Agalacticae
• neonates NO AB against COLIFORMS from mother cos cannot pass through placenta

Choroid Plexus in neonate no BBB

• hence start w vasculitis in choroid plexus
• then spread CSF, meningitis, encephalitis, abscess
• note staph aureus can also w entry lines;