title: Image analysis of the inferior rectus muscle in orbital floor fracture using cine mode magnetic resonance imaging.
abstract: OBJECTIVE
  The main cause of diplopia induced by orbital floor fracture is strangulation or damage of the extraocular muscles, and the outcome varies depending on the severity of trauma. In this study, we evaluated the dynamics of the eyeball and inferior rectus muscle based on cine magnetic resonance (MR) images acquired before surgery. The preoperative images and outcomes were retrospectively investigated.
  
  
  METHODS
  The subjects were 20 patients with orbital floor fracture. The patients repeated upgaze and downgaze, and images of these were acquired using cine mode magnetic resonance imaging (MRI). Image series were obtained in the sagittal direction including the eyeball and long axis of the optic nerve. The eyeball rotation angle, strangulation, and morphology of the inferior rectus muscle were evaluated in each phase.
  
  
  RESULTS
  On cine mode MRI, the outcome was poor in cases with a maximal inferior rectus muscle thickness of 5 mm or greater on extension (two or more times thicker than on the healthy side).
  
  
  CONCLUSIONS
  Our results suggest that the development of sequelae can be predicted by preoperative image analysis using cine MRI, which may be beneficial to help surgeons understand the mechanism of contracture.
authors.affiliation: Department of Plastic and Reconstructive Surgery, Kinki University Faculty of Medicine, 377-2 Ohno-higashi Osakasayama-city, Osaka, Japan. Electronic address: morotomi@med.kindai.ac.jp.
authors.forename: Tadaaki
authors.initials: T
authors.lastname: Morotomi
authors.affiliation: Department of Plastic and Reconstructive Surgery, Kinki University Faculty of Medicine, 377-2 Ohno-higashi Osakasayama-city, Osaka, Japan.
authors.forename: Tomomi
authors.initials: T
authors.lastname: Iuchi
authors.affiliation: Department of Plastic and Reconstructive Surgery, Kinki University Faculty of Medicine, 377-2 Ohno-higashi Osakasayama-city, Osaka, Japan.
authors.forename: Takahiro
authors.initials: T
authors.lastname: Hashimoto
authors.affiliation: Department of Plastic and Reconstructive Surgery, Kinki University Faculty of Medicine, 377-2 Ohno-higashi Osakasayama-city, Osaka, Japan.
authors.forename: Yu
authors.initials: Y
authors.lastname: Sueyoshi
authors.affiliation: Department of Plastic Surgery, Medical School of Kagawa University, Miki-Cho Ikenobe 1750-1, Kagawa Prefecture, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Nagasao
authors.affiliation: Department of Plastic and Reconstructive Surgery, Kinki University Faculty of Medicine, 377-2 Ohno-higashi Osakasayama-city, Osaka, Japan.
authors.forename: Noritaka
authors.initials: N
authors.lastname: Isogai
mesh_terms: D004172:Diplopia / Q000209:etiology; D005133:Eye Movements; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D009801:Oculomotor Muscles / Q000000981:diagnostic imaging*; D009917:Orbital Fractures / Q000000981:diagnostic imaging / Q000601:surgery; D016896:Treatment Outcome
keywords: Blow-out fractures; Diplopia; Eye movement; Inferior rectus muscle; MRI analysis; Orbital floor fractures