Contrast-enhanced flair imaging in the evaluation of infectious leptomeningeal diseases.
OBJECTIVE
The purpose of our study was to compare contrast-enhanced fluid-attenuated inversion recovery (FLAIR) images with contrast-enhanced T1 weighted images for infectious leptomeningitis.


METHODS
We studied twenty-four patients with a clinical suspicion of infectious meningitis with unenhanced FLAIR, contrast-enhanced T1 weighted and contrast-enhanced FLAIR MR sequences. Twelve patients had cytologic and biochemical diagnosis of meningitis on cerebrospinal fluid (CSF) examination obtained 48 h before or after the MR study. Sequences were considered positive if abnormal signal was seen in the subarachnoid space (cistern or sulci) or along pial surface.


RESULTS
Twenty-seven examinations in 24 patients were performed. Of the 12 patients (thirteen studies) in whom cytology was positive, unenhanced FLAIR images were positive in six cases (sensitivity 46%), contrast-enhanced FLAIR images were positive in 11 (sensitivity 85%), and contrast-enhanced T1 weighted MR images were positive in 11 patients (sensitivity 85%). Of the 12 patients (14 studies) in whom cerebrospinal fluid study was negative, unenhanced FLAIR images were negative in 13, contrast-enhanced FLAIR images were negative in 11, and contrast-enhanced T1 weighted MR images were negative in eight. Thus, the specificity of unenhanced FLAIR, contrast-enhanced FLAIR and contrast-enhanced T1 weighted images was 93, 79 and 57%, respectively.


CONCLUSIONS
Our results suggest that post-contrast FLAIR images have similar sensitivity but a higher specificity compared to contrast-enhanced T1 weighted images for detection of leptomeningeal enhancement. It can be a useful adjunct to post-contrast T1 weighted images in evaluation of infectious leptomeningitis.
Parmar
Hemant
H
Department of Neuroradiology, National Neuroscience Institute, 11 Jalan Tan Tock Seng, Singapore 308433, Singapore. parurad@hotmail.com
Sitoh
Yih-Yian
YY
Anand
Pooja
P
Chua
Violet
V
Hui
Francis
F
D000293:Adolescent; D000328:Adult; D000368:Aged; D002648:Child; D002675:Child, Preschool; D003287:Contrast Media / Q000008:administration & dosage; D005260:Female; D006801:Humans; D007089:Image Enhancement / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008581:Meningitis / Q000134:cerebrospinal fluid / Q000175:diagnosis*; D008875:Middle Aged; D012680:Sensitivity and Specificity
D003287:Contrast Media