Subdural empyema in 10 infants: US characteristics and clinical correlates.
OBJECTIVE
To investigate the ultrasonographic (US) characteristics of subdural empyema (SDE) and its differentiation from reactive subdural effusion (RSE) in infants with meningitis.


METHODS
Images in 10 infants with SDE with or without RSE complicating meningitis were retrospectively reviewed and correlated with clinical findings and compared with US and magnetic resonance (MR) images in four infants with meningitis and RSE.


RESULTS
At US, 15 of 16 SDEs in the 10 infants were seen as heterogeneous to hyperechoic convexity collections. Hyperechoic strands were seen in 12 SDEs. Other findings included a thick, echogenic inner membrane (n = 9), increased echogenicity of pia-arachnoid and exudates in the subarachnoid space (n = 16), mass effect (n = 16), and loculated extraaxial collections (n = 2). MR imaging findings correlated well with US and surgical results. At computed tomography, SDE was misinterpreted as RSE in one patient, due to the absence of inner membrane contrast material enhancement. Clinical outcome was related to the degree of brain damage consequent to meningitis and the chronicity of SDE. RSEs in seven infants (three with concurrent SDE) were anechoic; an inner membrane was seen in six, and increased pia-arachnoid echogenicity was seen in four.


CONCLUSIONS
SDE has complex US features that are helpful for differentiation from anechoic RSE in infants with meningitis.
Chen
C Y
CY
Department of Radiology, Tri-Service General Hospital and National Defense Medical Center, Taipei, Taiwan.
Huang
C C
CC
Chang
Y C
YC
Chow
N H
NH
Chio
C C
CC
Zimmerman
R A
RA
D003937:Diagnosis, Differential; D004453:Echoencephalography / Q000295:instrumentation / Q000379:methods; D013354:Empyema, Subdural / Q000000981:diagnostic imaging*; D005260:Female; D006801:Humans; D007223:Infant; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D016920:Meningitis, Bacterial / Q000175:diagnosis; D012189:Retrospective Studies; D013353:Subdural Effusion / Q000000981:diagnostic imaging; D013355:Subdural Space / Q000000981:diagnostic imaging / Q000473:pathology; D014057:Tomography, X-Ray Computed / Q000379:methods