Study of vessel mediated physiological parameters by perfusion magnetic resonance imaging

Student thesis: Doctoral Thesis

Abstract

This study investigates vessel mediated physiological parameters derived from perfusion MR imaging to better understand breast pathology so as to enable more accurate clinical decision making.
Chapter 1 and Chapter 2 provide an overview of the thesis and a brief introduction to the domain of the study. In Chapter 3, the key aspects of acquisition/ post processing strategies of generalized deconvolution based perfusion MR specific for breast pathology are explored. It is demonstrated that the deconvolution of relative enhancement (RE) of the tumors with an inflow corrected arterial input function (AIF) with a 50° inversion prepared Turbo Field Echo (TFE) sequence after a second bolus injection of 20 ml added to a routine breast MRI exam, would enable the quantification of perfusion parameters in human breast tumors
Chapter 4 explains how this optimized sequence is applied in 30 breast tumor patients, to test the feasibility of using a 2nd bolus injection, for the measurement of regional perfusion and permeability in human breast tumors. The preliminary results show that a pixel-by-pixel deconvolution analysis of T1 weighted bolus tracking data is feasible in breast tumors providing useful parametric maps of TBF, TVD, MTT. These data show that even though malignant and benign breast tumors can be characterized with the proposed measurement and post-processing protocol in terms of their perfusion values, the separation between the groups is not clear-cut.
In Chapter 5, the TBF in breast cancers is analyzed according to the classic (age, size, grade, lymph node status) as well as molecular (hormone receptor (HR) status, HER-2 protein and gene status) prognostic markers. It is shown that high TBF in poor prognostic cases (HER-2+ & HR- groups) serves to provide an early and physiologically specific indicator of the biological activity. Thus, TBF and its pattern may provide supporting prognostic information in a non-invasive manner. However, without validating with the existing immunohistochemical parameters such as MVD and VEGF expression, the exact angiogenic potential of TBF measurement cannot be elucidated fully.
However, the mean TBF values from these studies were higher than the results from Positron Emission Tomography (PET) studies. An accurate assessment of the TBF can become crucial in deciding the best management for breast cancer patients. Thus in Chapter 6, the potential causes leading to this overestimation were explored and a prebolus method to overcome these issues were proposed. Finally this prebolus method was successfully implemented in a small cohort of patients and the TBF values fall well within the range of PET literature data.
Date of Award16 Apr 2008
Original languageEnglish
Awarding Institution
  • Vrije Universiteit Brussel
SupervisorTadeusz Stadnik (Promotor), Robert Luypaert (Promotor), Axel Bossuyt (Jury), Jacques De Grève (Jury), Jan Lamote (Jury), Johan De Mey (Jury), Carla Boetes (Jury), Mireille Van Goethem (Jury) & Frank Peeters (Jury)

Keywords

  • breast tumors
  • MRI
  • DCE

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