Intra-cranial infections - imaging of CNS TB in HIV infected and un-

infected populations

Savvas Andronikou

The Children’s Hospital of Philadelphia

Neuro-radiologist ‘freshman’ in a developing country

Where are you working?

Have a CT scanner? Have an MRI scanner?

Two CNS Tuberculous Pathologies to Diagnose

A. Tuberculous Meningitis - TBM B. Tuberculous granuloma - Tuberculoma

TB Meningitis - Is it an emergency?

Presentation of TB Meningitis

• Altered level of consciousness

• Irritability

• Poor feeding

• Meningism

• Bulging fontanelle

• Neurologic deficits

• Cranial nerve palsies

• +/- Fever

YES this is an emergency

• For diagnosis

• Preceding CSF tapping

• Detect treatable complications

TBM Full-house for the novice

TBM Triad

• Basal Enhancement

• Infarction of deep nuclei

• Hydrocephalus

Andronikou S et al. Definitive neuroradiological diagnostic features of tuberculous meningitis in children. Pediatr Radiol. 2004 Nov;34(11):876-85

Bacterial meningitis

Most diagnostic feature - meningeal enhancement

Przybojewski S, Andronikou S, Wilmshurst J. Objective CT criteria todetermine the presence of abnormal basal enhancement in children with suspectedtuberculous meningitis. Pediatr Radiol. 2006 Jul;36(7):687-96

This is CT: normal vessels vs. meningeal enhancement

Normal Vessel Enhancement Double Lines of Abnormal Meningeal Enhancement

Enhancement of the cranial nerves

Patterns of basal enhancement - cranial nerves

What if we have no IVI contrast?

Andronikou S, Smith B, Hatherhill M, Douis H, Wilmshurst J. Definitive neuroradiological diagnostic features of tuberculous meningitis in children.Pediatr Radiol. 2004 Nov;34(11):876-85

Does the cisternal density enhance?

Variations on cisternal density

TBM triad without contrast

1. Hyperdense exudate

2. Infarction deep nuclei

3. Hydrocephalus

Treatable Complication of TBM: Hydrocephalus

TBM HydrocephalusMinority:

Non-communicating - DrainMajority:

Communicating - no drain

Non -Communicating vs. Communicating H/C

Minority: Non-communicating - DrainMajority:

Communicating - no drain

Not possible to predict which it is without air encephalography

Complications: Infarction

Brainstem infarctions - not visible on CT…

van der Merwe DJ, Andronikou S, Van Toorn R, Pienaar M. Childs Nerv Syst. 2009 Aug;25(8):949-54

Complications: border-zone infarction

How does HIV affect your diagnostic ability?

• HIV makes for a higher likelihood of a child with TB getting TB Meningitis

BUT

• Less able to mount an immune response

• Less pronounced inflammatory exudate

• Less visible basal density or enhancement

• Less basal ganglia infarctions

• Less likely to get hydrocephalus

• More often atrophy – and hydrocephalus more likely communicating

Both these patients have TB meningitis

Dekker G, Andronikou S, van Toorn R, Scheepers S, Brandt A, Ackermann C. MRI findings in children with tuberculous meningitis: a comparison of HIV-infected and non-infected patients. Childs Nerv Syst. 2011 Apr 15.

Is there basal enhancement?Are there infarctions?Is there hydrocephalus?

Is there basal enhancement?Are there infarctions?Is there hydrocephalus?

Non-emergency: first time focal seizure

Ring-enhancing lesions: TB granuloma TB abscess Neurocysticercosis

Tuberculoma is CT Iso-dense and T2 black

10 points for novice outreach radiologists:

• TBM requires urgent imaging - radiologist is critical • Diagnosis• Complications • Prior to CSF sampling

• Use CT – it may be your only tool• Work without contrast – you may not have any• Diagnostic TBM triad: basal enhancement; BG Infarcts; HC• Double lines and chiasm to detect mild basal enhancement• Hyperdense exudates are diagnostic • Avoid committing to communicating vs. non-communicating HC• BG and borderzone infarcts – CT can miss these• HIV dampens basal enhancement• TB granuloma causes seizure: CT Iso-dense and T2 black