Thread by @ahkady86

#FOAMneu #FOAMed
#neurorad @vmargar
MRI simplified patterned approach in CNS infection:
Using T1, T2 and Contrast enhancement pattern, CNS infection could be classified into:
Ring enhancing lesion, Basal ganglia SOL, Grey matter hyperintensitie, White matter hyperintensitie.

Ring enhancing lesion:
Abscesses show a thin smooth rim, whereas nodular irregular rim seen in neoplasm. SWI show a smooth complete ring of susceptibility in abscess, whereas incomplete irregular ring in neoplasms. ADC show low values in abscess, whereas high values in neoplasms.

Differentiating of ring enhancing etiologies:
DWI of bacterial & tubercular show central restriction, whereas fungal shows wall & projections restriction, though not core
MR spectroscopy of bacterial shows amino acids peaks, tubercular lipids peaks, whereas fungal multiple peaks

Basal ganglia SOL etiologies:
8:Toxoplasmosis, Gd enhancement, no DWI restriction, decreased perfusion, MRS lipid peaks.
9:Primary CNS lymphoma, Gd enhancement, marked DWI restriction, increased perfusion, MRS choline peak.
10: Cryptococcosis, no Gd enhancement, DWI restriction.

Grey matter hyperintensities:
Infection & infarction showed DWI restriction, whereas infection shows increased perfusion, infarction shows decreased perfusion
Location of lesion highlight etiology, medial temporal >> HSV, Cortex BG & BS >> Japanese virus, pulvinar & BG >> CJD

White matter hyperintensities:
HIV encephalopathy bilateral perventricular symmetrical lesion, isointense in T1, no Gd enhancement.
Progressive multifocal leukoencephalopathy asymmetrical perventricular lesion, peripheral DWI restriction, hypointense in T1, may Gd enhancement.