title: MRI analysis of chronological changes in free-flap volume in head and neck reconstruction by volumetry.
abstract: OBJECTIVE
  To evaluate changes in flap volumes for head and neck cancer patients by MRI.
  
  
  METHODS
  MRI examinations of a total of 21 head and neck cancer patients (13 males and 8 females; average age, 67 years) were performed after surgery to monitor changes in flap volumes, including muscle and fat content, using volumetric analysis of T2-weighted images at 1, 3, 6, and 12 months after surgery.
  
  
  RESULTS
  Fat-to-muscle ratios of all flaps at 1 month varied (muscle/fat ratio, 0.04-0.96). Flap volumes in all patients decreased at 12 months after surgery. The average final volumes of overall, muscle, and fat volumes reached 76.9% ± 5.2%, 37.1% ± 3.7%, and 85.5% ± 5.7%, respectively. The average fat volume slightly increased between 6 and 12 months, whereas compared with the fat volume, the average muscle volume significantly decreased (p<0.001).
  
  
  CONCLUSIONS
  The final overall flap volume in all patients decreased to approximately 25% of the original volume after surgery, which primarily resulted from muscle atrophy. Therefore fat-rich flaps may maintain flap volumes after surgery. MRI is a useful method to evaluate the size and shape of flaps of the head and neck.
authors.affiliation: Department of Oral and Maxillofacial Surgery, Tokai University School of Medicine, 143 Shimokasuya, Isehara, Kanagawa 259-1193, Japan. yukiyama20@hotmail.com.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Sakamoto
authors.forename: Taro
authors.initials: T
authors.lastname: Takahara
authors.forename: Yoshihide
authors.initials: Y
authors.lastname: Ota
authors.forename: Takayuki
authors.initials: T
authors.lastname: Aoki
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamazaki
authors.forename: Mitsunobu
authors.initials: M
authors.lastname: Otsuru
authors.forename: Miho
authors.initials: M
authors.lastname: Takahashi
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Aoyama
authors.forename: Akihiro
authors.initials: A
authors.lastname: Kaneko
authors.forename: Shunichi
authors.initials: S
authors.lastname: Kawada
authors.forename: Tamaki
authors.initials: T
authors.lastname: Ichikawa
authors.forename: Kotaro
authors.initials: K
authors.lastname: Imagawa
authors.forename: Muneo
authors.initials: M
authors.lastname: Miyasaka
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism; D000368:Aged; D001284:Atrophy; D044964:Cervicoplasty / Q000379:methods*; D005260:Female; D006258:Head and Neck Neoplasms / Q000601:surgery*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009334:Neck Muscles / Q000378:metabolism / Q000473:pathology; D011184:Postoperative Period; D013524:Surgical Flaps / Q000473:pathology*; D013997:Time Factors