title: Application of a biodegradable macromolecular contrast agent in dynamic contrast-enhanced MRI for assessing the efficacy of indocyanine green-enhanced photothermal cancer therapy.
abstract: OBJECTIVE
  To investigate the effectiveness of a polydisulfide-based biodegradable macromolecular contrast agent, (Gd-DTPA)-cystamine copolymers (GDCC), in assessing the efficacy of indocyanine green-enhanced photothermal cancer therapy using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI).
  
  
  METHODS
  Breast cancer xenografts in mice were injected with indocyanine green and irradiated with a laser. The efficacy was assessed using DCE-MRI with GDCC of 40 kDa (GDCC-40) at 4 hours and 7 days after the treatment. The uptake of GDCC-40 by the tumors was fit to a two-compartment model to obtain tumor vascular parameters, including fractional plasma volume (f(PV)), endothelium transfer coefficient (K(PS)), and permeability surface area product (PS).
  
  
  RESULTS
  GDCC-40 resulted in similar tumor vascular parameters at three doses, with larger standard deviations at lower doses. The values of f(PV), K(PS), and PS of the treated tumors were smaller (P < 0.05) than those of untreated tumors at 4 hours after the treatment and recovered to pretreatment values (P > 0.05) at 7 days after the treatment.
  
  
  CONCLUSIONS
  DCE-MRI with GDCC-40 is effective for assessing tumor early response to dye-enhanced photothermal therapy and detecting tumor relapse after the treatment. GDCC-40 has a potential to noninvasively monitor anticancer therapies with DCE-MRI.
authors.affiliation: Department of Pharmaceutics and Pharmaceutical Chemistry, University of Utah, Salt Lake City, Utah, USA.
authors.forename: Yi
authors.initials: Y
authors.lastname: Feng
authors.forename: Lyska
authors.initials: L
authors.lastname: Emerson
authors.forename: Eun-Kee
authors.initials: EK
authors.lastname: Jeong
authors.forename: Dennis L
authors.initials: DL
authors.lastname: Parker
authors.forename: Zheng-Rong
authors.initials: ZR
authors.lastname: Lu
mesh_terms: D000818:Animals; D004396:Coloring Agents / Q000494:pharmacology*; D016001:Confidence Intervals; D003287:Contrast Media / Q000493:pharmacokinetics*; D003538:Cystamine / Q000494:pharmacology*; D005260:Female; D019786:Gadolinium DTPA / Q000493:pharmacokinetics*; D007089:Image Enhancement / Q000379:methods*; D007091:Image Processing, Computer-Assisted; D007208:Indocyanine Green / Q000494:pharmacology*; D028022:Low-Level Light Therapy / Q000379:methods*; D046911:Macromolecular Substances / Q000493:pharmacokinetics; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008325:Mammary Neoplasms, Experimental / Q000473:pathology*; D051379:Mice; D008819:Mice, Nude; D011108:Polymers / Q000494:pharmacology
chemical_list: D004396:Coloring Agents; D003287:Contrast Media; D046911:Macromolecular Substances; D011108:Polymers; D007208:Indocyanine Green; D019786:Gadolinium DTPA; D003538:Cystamine