Brain infection protocol (MRI)

MRI protocol for brain infection assessment is a group of MRI sequences put together to best approach CNS infections in general.

Note: This article is intended to outline some general principles of protocol design. The specifics will vary depending on MRI hardware and software, radiologist's and referrer's preference, institutional protocols, patient factors (e.g. allergy) and time constraints.

Sequences

A good protocol for this purpose involves at least:

• T1
  • sequence: axial and sagittal
• T2
  • sequence: axial
• FLAIR
  • sequence: axial
• DWI/ADC
  • purpose: relevant for showing restriction in brain abscesses
• T1 C+ (Gd)
  • sequence: axial and coronal ​
  • Gadolinium based contrast agents (GBCAs) for CNS :
    • gadoterate meglumine (Dotarem®)
    • gadobutrol  (Gadavist®)
    • gadopentetate dimeglumine (Magnevist®)
    • gadobenate dimeglumine (MultiHance®)
    • gadodiamide (Omniscan®)
    • gadoversetamide (OptiMARK®)
    • gadoteridol (ProHance®)
  • all these GBCAs are approved by FDA at identical administered total doses of 0.1mmol/kg body weight
• FLAIR C+ (Gd)
  • sequence: axial
  • purpose: more sensitive and specific than T1 C+ (Gd) in the diagnosis of meningitis
• SWI

Advanced MRI techniques may be helpful to exclude some differential diagnosis and thus they may be considered as part of the protocol.

• MR perfusion
  • purpose: rCBV is commonly reduced in the surrounding edema of an infectious process such as an abscess
• MR spectroscopy
  • purpose: useful to exclude tumor metabolites peaks