title: 11.7 Tesla magnetic resonance microimaging of laryngeal tissue architecture.
abstract: OBJECTIVE
  High-resolution imaging of vocal folds that distinguishes vocal fold (VF) layered microstructure and VF implants would provide a key experimental tool for translational research investigating biomaterial-based interventions to treat vocal fold scar. To establish proof of concept, we studied whether 11.7 Tesla (T) magnetic resonance (MR) microimaging provides the needed resolution to resolve vocal fold tissue architecture.
  
  
  METHODS
  We performed ex vivo MR microimaging of fixed ferret and canine larynges to determine whether changes in the layered architecture can be detected in the presence of scar and subsequent to biomaterial injections into the vocal folds. Serial section histological analyses were done to corroborate MR microimaging findings.
  
  
  METHODS
  Multiple axial and transverse/coronal 300-microm slices were obtained using an 11.7 T MR spectrometer/500 MHz for proton with gradient-recalled echo and rapid acquisition with relaxation enhancement imaging sequences.
  
  
  RESULTS
  High-resolution (39 microm/pixel) MR microimages distinguished VF epithelium, lamina propria, muscle, and cartilage in ferret and canine larynges. In ferret scarred VFs (n = 25), collagen-rich dense scar tissue was distinguishable from contralateral nonscarred VFs and from normal ferret VFs (n = 25), as confirmed on histology. MR microimaging accurately detected injected autologous fat, hyaluronic acid-based and polyethylene glycol (PEG)-based implants injected into both ferret and canine VFs. Importantly, MRI accurately showed resorption of PEG implants in ferrets and canines, as confirmed on histology. Additionally, ex vivo MR spectroscopy distinguished fat from PEG-based implants.
  
  
  CONCLUSIONS
  Ex vivo 11.7 T MR microimaging provided high-resolution images of ferret and canine laryngeal tissue microstructure, although the superficial lamina propria could not be distinguished. Histology confirmed MR microimaging findings, indicating utility of MR microimaging of modeled scar, implant residence time, and tissue responses, thus providing integrative insight relevant to translational research.
authors.affiliation: Department of Medicine, Boston University School of Medicine Boston, Massachusetts 02118, USA. vherrera@bu.edu
authors.forename: Victoria L M
authors.initials: VL
authors.lastname: Herrera
authors.forename: Jason C
authors.initials: JC
authors.lastname: Viereck
authors.forename: Gerardo
authors.initials: G
authors.lastname: Lopez-Guerra
authors.forename: Yoshihiko
authors.initials: Y
authors.lastname: Kumai
authors.forename: James
authors.initials: J
authors.lastname: Kobler
authors.forename: Sandeep
authors.initials: S
authors.lastname: Karajanagi
authors.forename: Hyoungshin
authors.initials: H
authors.lastname: Park
authors.forename: Robert
authors.initials: R
authors.lastname: Hillman
authors.forename: Steven M
authors.initials: SM
authors.lastname: Zeitels
mesh_terms: D000818:Animals; D004285:Dogs; D005289:Ferrets; D007830:Larynx / Q000033:anatomy & histology* / Q000601:surgery; D008279:Magnetic Resonance Imaging / Q000379:methods*