MRI findings and spreading patterns of necrotizing external otitis: is a poor outcome predictable?
OBJECTIVE
To evaluate spreading patterns of necrotizing external otitis (NEO) by magnetic resonance imaging (MRI) and to identify spreading patterns related to a poor outcome.


METHODS
Fourteen patients with NEO were divided into good and poor outcome groups according to their final clinical outcomes. Initial MRI images were retrospectively reviewed for regional abnormalities, and follow-up MRI images were reviewed for ICA flow void abnormality and for the following five spreading patterns: medial, crossed, anterior, intracranial, and combined. The frequencies of the abnormal flow void or spreading patterns were compared between the good and poor response groups.


RESULTS
Seven (50%) and seven (50%) patients were respectively allocated to the good and poor outcome groups. Retrocondylar fat infiltration was the most commonest finding on initial MRI images (93%). The frequencies of the abnormal flow void and spreading patterns in the good and poor groups, respectively, were: abnormal flow void, 0 and four (57%); anterior, two (29%) and three (43%); medial, six (86%) and seven (100%); crossed, six (86%) and seven (100%); intracranial middle cranial fossa, one (14%) and four (57%); intracranial posterior cranial fossa, four (57%) and six (86%); intracranial foramen magnum, one (14%) and six (86%).


CONCLUSIONS
NEO almost always involves the retrocondylar fat and spreads via various pathways to extracranial or intracranial spaces. The presence of an abnormal flow void and intracranial dural enhancement, particularly in the middle cranial fossa and foramen magnum, may indicate a poor prognosis.
Kwon
B J
BJ
Department of Radiology, Seoul National University College of Medicine, and Clinical Research Institute, Seoul National University Hospital, South Korea.
Han
M H
MH
Oh
S H
SH
Song
J J
JJ
Chang
K-H
KH
D000368:Aged; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D004388:Dura Mater / Q000473:pathology; D004431:Ear, External / Q000473:pathology; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009302:Nasopharyngeal Diseases / Q000473:pathology; D010032:Otitis Externa / Q000188:drug therapy / Q000473:pathology*; D011379:Prognosis
D000900:Anti-Bacterial Agents