title: Radiochemotherapy-induced changes of tumour vascularity and blood supply estimated by dynamic contrast-enhanced CT and fractal analysis in malignant head and neck tumours.
abstract: OBJECTIVE
  To investigate radiochemotherapy (RChT)-induced changes of transfer coefficient (K(trans)) and relative tumour blood volume (rTBV) estimated by dynamic contrast-enhanced CT (DCE-CT) and fractal analysis in head and neck tumours (HNTs).
  
  
  METHODS
  DCE-CT was performed in 15 patients with inoperable HNTs before RChT, and after 2 and 5 weeks. The dynamics of K(trans) and rTBV as well as lacunarity, slope of log(lacunarity) vs log(box size), and fractal dimension were compared with tumour behaviour during RChT and in the 24-month follow-up.
  
  
  RESULTS
  In 11 patients, an increase of K(trans) and/or rTBV after 20 Gy followed by a decrease of both parameters after 50 Gy was noted. Except for one local recurrence, no tumour residue was found during the follow-up. In three patients with partial tumour reduction during RChT, a decrease of K(trans) accompanied by an increase in rTBV between 20 and 50 Gy was detected. In one patient with continuous elevation of both parameters, tumour progressed after RChT. Pre-treatment difference in intratumoral heterogeneity with its decline under RChT for the responders vs non-responders was observed.
  
  
  CONCLUSIONS
  Initial growth of K(trans) and/or rTBV followed by further reduction of both parameters along with the decline of the slope of log(lacunarity) vs log(box size) was associated with positive radiochemotherapeutic response. Increase of K(trans) and/or rTBV under RChT indicated a poor outcome.
  
  
  CONCLUSIONS
  The modification of K(trans) and rTBV as measured by DCE-CT may be applied for the assessment of tumour sensitivity to chose RChT regimen and, consequently, to reveal clinical impact allowing individualization of RChT strategy in patients with HNT.
authors.affiliation: 1 Department of Neuroradiology, Medical Faculty and University Hospital Carl Gustav Carus, TU Dresden, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Abramyuk
authors.forename: V
authors.initials: V
authors.lastname: Hietschold
authors.forename: S
authors.initials: S
authors.lastname: Appold
authors.forename: R
authors.initials: R
authors.lastname: von Kummer
authors.forename: N
authors.initials: N
authors.lastname: Abolmaali
mesh_terms: D000368:Aged; D059248:Chemoradiotherapy; D003287:Contrast Media; D005260:Female; D005500:Follow-Up Studies; D017709:Fractals; D006258:Head and Neck Neoplasms / Q000098:blood supply / Q000000981:diagnostic imaging / Q000532:radiotherapy*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D036542:Tomography, Spiral Computed / Q000379:methods*
chemical_list: D003287:Contrast Media