Clinical implications of increased fractional anisotropy in meningitis associated with brain abscess.
OBJECTIVE
To look for the clinical implications of increased cortical fractional anisotropy (FA) in meningitis patients associated with brain abscess.


METHODS
Diffusion tensor imaging was performed in 10 patients of meningitis associated with brain abscess and 10 controls. The region of interest analysis was performed to calculate FA and mean diffusivity values from the abscess cavity and cortical regions of patients (enhancing and nonenhancing meninges on postcontrast T1-weighted images) and controls.


RESULTS
Significantly increased FA values with no change in mean diffusivity values were found in enhancing (FA = 0.113 +/- 0.023, P = 0.000) as well as nonenhancing (FA = 0.085 +/- 0.009, P = 0.000) cortical region of patients compared with controls (FA = 0.067 +/- 0.010).


CONCLUSIONS
Increased FA values in the enhancing as well as nonenhancing cortical regions suggest diffuse inflammatory activity in the pia-arachnoid in meningitis patients. It also suggests that FA may be a better indicator of active and diffuse meningeal inflammation than postcontrast T1-weighted images.
Nath
Kavindra
K
Department of Radiodiagnosis, Sanjay Gandhi Postgraduate Institute of Medical Sciences, Lucknow, India.
Husain
Mazhar
M
Trivedi
Richa
R
Kumar
Raj
R
Prasad
Kashi N
KN
Rathore
R K S
RK
Gupta
Rakesh K
RK
D000293:Adolescent; D016880:Anisotropy; D001922:Brain Abscess / Q000134:cerebrospinal fluid / Q000150:complications / Q000175:diagnosis*; D016022:Case-Control Studies; D002540:Cerebral Cortex / Q000473:pathology; D003287:Contrast Media; D038524:Diffusion Magnetic Resonance Imaging / Q000379:methods*; D017352:Echo-Planar Imaging; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D008578:Meninges / Q000473:pathology; D008581:Meningitis / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000209:etiology; D013492:Suppuration
D003287:Contrast Media; D019786:Gadolinium DTPA