MRI findings of the middle ear in infants.
CONCLUSIONS
While infants under the age of 1 year exhibited a high rate of abnormal intensities in the middle ear and mastoid cavities, older infants showed no abnormal intensities in these regions. From the signal intensity on T1- and T2-weighted MRI, the abnormal intensities in the middle ear cavity were considered to represent liquid effusion. Taken together with the findings of temporal bone CT, the abnormal intensities in the mastoid cavity were considered to represent bone marrow.


OBJECTIVE
Histopathological studies of the temporal bone and tympanometry investigations have reported the presence of mesenchyme and liquid effusion in the middle ear cavity of infants. However, very few CT or MRI middle ear cavity findings of newborns and infants have been published, and none have included the mastoid cavity. We therefore performed an MRI study of the middle ear and mastoid cavities of infants under 2 years old (83 cases, 88 imaging series).


METHODS
MRI (1.5 T) was originally performed on suspicion of brain disorders in infants aged under 2 years. All MRI slices were studied and classified on the basis of the distribution of abnormal intensities in the middle ear and mastoid cavities.


RESULTS
All the abnormal imaging appeared in infants under 1 year old, in particular, 74.24% (n=49) of abnormal imaging appeared in the first 20 weeks after birth.
Sano
Masaki
M
Department of Otorhinolaryngology and Head & Neck Surgery, Graduate School of Medicine and Faculty of Medicine, University of Tokyo, and Division of Radiology, University of Tokyo Hospital, Tokyo, Japan. neurootolsano@ybb.ne.jp
Kaga
Kimitaka
K
Mima
Kazuo
K
D002675:Child, Preschool; D003937:Diagnosis, Differential; D004432:Ear, Middle / Q000473:pathology*; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008416:Mastoid / Q000473:pathology; D010034:Otitis Media with Effusion / Q000175:diagnosis*; D012189:Retrospective Studies; D012720:Severity of Illness Index