title: MRI of postoperative maxillary cysts.
abstract: OBJECTIVE
  The purpose of this study is to review the MR characteristics of postoperative maxillary cysts (POMC).
  
  
  METHODS
  The MR findings in 24 patients with 38 surgically confirmed POMC were retrospectively reviewed.
  
  
  RESULTS
  Of 32 cysts detected by MRI, 31 cysts (96.9%) were well demarcated. Nineteen cysts (59.4%) were smooth and the others (40.6%) were irregular. Thirty cysts (93.8%) had signal intensities ranging from that of muscle to that of subcutaneous fat on T1-weighted imaging. On T2-weighted imaging 16 homogeneous (50.0% and 5 inhomogeneous (15.6%) cysts showed signal intensities equal to or higher than subcutaneous fat. The peripheral rims of 11 ring-like cysts (34.4%) also showed signal intensities equal to or higher than subcutaneous fat on T2-weighted imaging. Nine patients (37.5%) had multiple cysts. Their characteristic high signal intensities or ring-like patterns on T2-weighted imaging and well-demarcated margins enabled them to be discriminated from other tumors of the maxillary sinus, such as carcinoma.
  
  
  CONCLUSIONS
  MR imaging is useful for diagnosis of POMC.
authors.affiliation: Department of Radiology, Hamamatsu University School of Medicine, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Isoda
authors.forename: Y
authors.initials: Y
authors.lastname: Takehara
authors.forename: T
authors.initials: T
authors.lastname: Masui
authors.forename: A
authors.initials: A
authors.lastname: Seki
authors.forename: M
authors.initials: M
authors.lastname: Takahashi
authors.forename: M
authors.initials: M
authors.lastname: Kaneko
mesh_terms: D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D007570:Jaw Cysts / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008439:Maxillary Diseases / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D008443:Maxillary Sinus / Q000601:surgery; D008875:Middle Aged; D011183:Postoperative Complications / Q000175:diagnosis*