Abstract

Thermal ablation is a minimally invasive cancer treatment that aims to
totally eradicate the tumor. Lesions up to 3-5 cm can be eradicated with
lethal heat. The ablation zone is recognized as an absent perfusion zone on
imaging. Reliable imaging for treatment evaluation plays an important role
in improving the efficacy of this approach. In this work, we aimed to
investigate methods which allow for early and reliable evaluation of thermal
ablation of focal tumors.
We analyzed the predictive value of image patterns on ce-CT and PET/CT
scans one day after the RF ablation procedure of liver metastases. The
absence of FDG uptake was found to be indicative of successfully treated
tumors. Early focal nodular enhancement or tracer distribution are very
likely corresponding to residual tumor. The diagnostic performance of ce-CT
and PET/CT were investigated using ROC analysis. PET/CT did not
demonstrate an improved diagnostic performance over ce-CT alone in the
early evaluation of RF ablation of liver metastases.
Dual Energy CT (DECT) technology has a high sensitivity for the detection of
focal lesions. The low keV monochromatic reconstruction images and iodine
maps show an improved delineation of the treated avascular regions after RF
ablation of tumors in liver, lung and kidney from the surrounding
parenchyma. We believe that DECT can be a valuable asset in the
differentiation of residual tumors from benign inflammatory changes,
commonly found after ablation.
We assessed the value of geometric coverage as a predictive factor for local
tumor progression (LTP). The liver on ce-CT before and 24h after RF ablation
was geometrically aligned using an interactive approach. On the fusion
image, the margin between the index tumor and the ablation zone was an
excellent predictive factor for LTP of liver metastases treated with thermal
ablation.
Date of Award4 Jul 2017
Original languageEnglish
Awarding Institution
  • Vrije Universiteit Brussel
SupervisorJohan De Mey (Promotor), J. Vandemeulebroucke (Co-promotor), Nico Buls (Co-promotor), Mark De Ridder (Jury), Mieke Cannie (Jury), Hendrik Reynaert (Jury), Bart Neyns (Jury), Tony Lahoutte (Jury), J.P. Gérard (Jury) & V. Vandecaveye (Jury)

Keywords

  • Thermal ablation
  • cancer
  • treatment
  • tumor
  • PET/CT scan
  • metastase

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