title: Monitoring targeted therapy using dual-energy CT: semi-automatic RECIST plus supplementary functional information by quantifying iodine uptake of melanoma metastases.
abstract: OBJECTIVE
  Supplementary functional information can contribute to assess response in targeted therapies. The aim of this study was to evaluate semi-automatic RECIST plus iodine uptake (IU) determination in melanoma metastases under BRAF inhibitor (vemurafenib) therapy using dual-energy computed tomography (DECT).
  
  
  METHODS
  Nine patients with stage IV melanoma treated with a BRAF inhibitor were included. Contrast-enhanced DECT was performed before and twice after treatment onset. Changes in tumor size were assessed according to RECIST. Quantification of IU (absolute value for total IU (mg) and volume-normalized IU (mg/ml)) was based on semi-automatic tumor volume segmentation. The decrease compared with baseline was calculated.
  
  
  RESULTS
  The mean change of RECIST diameter sum per patient was -47% at the first follow-up (FU), -56% at the second FU (P < 0.01). The mean normalized IU per patient was -21% at the first FU (P < 0.2) and -45% at the second FU (P < 0.01). Total IU per patient, combining both normalized IU and volume, showed the most pronounced decrease: -89% at the first FU and -90% at the second FU (P < 0.01).
  
  
  CONCLUSIONS
  Semi-automatic RECIST plus IU quantification in DECT enables objective, easy and fast parameterization of tumor size and contrast medium uptake, thus providing 2 complementary pieces of information for response monitoring applicable in daily routine.
authors.affiliation: Department of Radiology, German Cancer Research Center, Im Neuenheimer Feld 280, Heidelberg, D-69120, Germany. m.uhrig@dkfz-heidelberg.de
authors.forename: M
authors.initials: M
authors.lastname: Uhrig
authors.forename: M
authors.initials: M
authors.lastname: Sedlmair
authors.forename: H P
authors.initials: HP
authors.lastname: Schlemmer
authors.forename: J C
authors.initials: JC
authors.lastname: Hassel
authors.forename: M
authors.initials: M
authors.lastname: Ganten
mesh_terms: D000328:Adult; D000368:Aged; D003287:Contrast Media; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D007211:Indoles / Q000627:therapeutic use*; D007455:Iodine / Q000378:metabolism*; D008297:Male; D008545:Melanoma / Q000000981:diagnostic imaging / Q000188:drug therapy* / Q000473:pathology / Q000556:secondary*; D008875:Middle Aged; D048493:Proto-Oncogene Proteins B-raf / Q000037:antagonists & inhibitors*; D013449:Sulfonamides / Q000627:therapeutic use*; D014057:Tomography, X-Ray Computed / Q000379:methods*; D000077484:Vemurafenib
chemical_list: D003287:Contrast Media; D007211:Indoles; D013449:Sulfonamides; D000077484:Vemurafenib; D007455:Iodine; D048493:Proto-Oncogene Proteins B-raf