title: Magnetization transfer-based 3D visualization of foot peripheral nerves.
abstract: OBJECTIVE
  To investigate magnetization transfer (MT) effects as a new source of contrast for imaging and tracking of peripheral foot nerves.
  
  
  METHODS
  Two sets of 3D spoiled gradient-echo images acquired with and without a saturation pulse were used to generate MT ratio (MTR) maps of 260 μm in-plane resolution for eight volunteers at 3T. Scan parameters were adjusted to minimize signal loss due to T2 dephasing, and a dedicated coil was used to improve the inherently low signal-to-noise ratio of small voxels. Resulting MTR values in foot nerves were compared with those in surrounding muscle tissue.
  
  
  RESULTS
  Average MTR values for muscle (45.5 ± 1.4%) and nerve (21.4 ± 3.1%) were significantly different (P < 0.0001). In general, the difference in MTR values was sufficiently large to allow for intensity-based segmentation and tracking of foot nerves in individual subjects. This procedure was termed MT-based 3D visualization.
  
  
  CONCLUSIONS
  The MTR serves as a new source of contrast for imaging of peripheral foot nerves and provides a means for high spatial resolution tracking of these structures. The proposed methodology is directly applicable on standard clinical MR scanners and could be applied to systemic pathologies, such as diabetes.
authors.affiliation: Laboratory of Functional and Metabolic Imaging (LIFMET), Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland. ralf.mekle@gmail.com
authors.forename: Ralf
authors.initials: R
authors.lastname: Mekle
authors.forename: Benedicte
authors.initials: B
authors.lastname: Mortamet
authors.forename: Cristina
authors.initials: C
authors.lastname: Granziera
authors.forename: Gunnar
authors.initials: G
authors.lastname: Krueger
authors.forename: Nicolas
authors.initials: N
authors.lastname: Chevrey
authors.forename: Nicolas
authors.initials: N
authors.lastname: Theumann
authors.forename: Guilio
authors.initials: G
authors.lastname: Gambarota
mesh_terms: D000328:Adult; D000465:Algorithms; D005260:Female; D005528:Foot / Q000033:anatomy & histology* / Q000294:innervation*; D006801:Humans; D007089:Image Enhancement / Q000379:methods; D007090:Image Interpretation, Computer-Assisted / Q000379:methods*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D010525:Peripheral Nerves / Q000033:anatomy & histology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult