title: Terahertz Imaging of Cutaneous Edema: Correlation With Magnetic Resonance Imaging in Burn Wounds.
abstract: In vivo visualization and quantification of edema, or 'tissue swelling' following injury, remains a clinical challenge. Herein, we investigate the ability of reflective terahertz (THz) imaging to track changes in tissue water content (TWC)-the direct indicator of edema-by comparison to depth-resolved magnetic resonance imaging (MRI) in a burn-induced model of edema.
  
  
  
  A partial thickness and full thickness burns were induced in an in vivo rat model to elicit unique TWC perturbations corresponding to burn severity. Concomitant THz surface maps and MRI images of both burn models were acquired with a previously reported THz imaging system and T2-weighted MRI, respectively, over 270 min. Reflectivity was analyzed for the burn contact area in THz images, while proton density (i.e., mobile TWC) was analyzed for the same region at incrementally increasing tissue depths in companion, transverse MRI images. A normalized cross correlation of THz and depth-dependent MRI measurements was performed as a function of time in histologically verified burn wounds.
  
  
  
  For both burn types, strong positive correlations were evident between THz reflectivity and MRI data analyzed at greater tissue depths (>258 μm). MRI and THz results also revealed biphasic trends consistent with burn edema pathogenesis.
  
  
  
  This paper offers the first in vivo correlative assessment of mobile TWC-based contrast and the sensing depth of THz imaging.
  
  
  
  The ability to implement THz imaging immediately following injury, combined with TWC sensing capabilities that compare to MRI, further support THz sensing as an emerging tool to track fluid in tissue.
authors.forename: Neha
authors.initials: N
authors.lastname: Bajwa
authors.forename: Shijun
authors.initials: S
authors.lastname: Sung
authors.forename: Daniel B
authors.initials: DB
authors.lastname: Ennis
authors.forename: Michael C
authors.initials: MC
authors.lastname: Fishbein
authors.forename: Bryan N
authors.initials: BN
authors.lastname: Nowroozi
authors.forename: Dan
authors.initials: D
authors.lastname: Ruan
authors.forename: Ashkan
authors.initials: A
authors.lastname: Maccabi
authors.forename: Jeffry
authors.initials: J
authors.lastname: Alger
authors.forename: Maie A St
authors.initials: MAS
authors.lastname: John
authors.forename: Warren S
authors.initials: WS
authors.lastname: Grundfest
authors.forename: Zachary D
authors.initials: ZD
authors.lastname: Taylor
mesh_terms: D000818:Animals; D002056:Burns / Q000000981:diagnostic imaging*; D004195:Disease Models, Animal; D004487:Edema / Q000000981:diagnostic imaging*; D007090:Image Interpretation, Computer-Assisted; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D012815:Signal Processing, Computer-Assisted; D055069:Terahertz Imaging / Q000379:methods*