title: Arterial input function calculation in dynamic contrast-enhanced MRI: an in vivo validation study using co-registered contrast-enhanced ultrasound imaging.
abstract: OBJECTIVE
  Developing a method of separating intravascular contrast agent concentration to measure the arterial input function (AIF) in dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) of tumours, and validating its performance in phantom and in vivo experiments.
  
  
  METHODS
  A tissue-mimicking phantom was constructed to model leaky tumour vasculature and DCE-MR images of this phantom were acquired. An in vivo study was performed using tumour-bearing rabbits. Co-registered DCE-MRI and contrast-enhanced ultrasound (CEUS) images were acquired. An independent component analysis (ICA)-based method was developed to separate the intravascular component from DCE-MRI. Results were validated by comparing the time-intensity curves with the actual phantom and in vivo curves.
  
  
  RESULTS
  Phantom study: the AIF extracted using ICA correlated well with the true intravascular curve. In vivo study: the AIFs extracted from DCE-MRI using ICA were very close to the true AIF. Intravascular component images were very similar to the CEUS images. The contrast onset times and initial wash-in slope of the ICA-derived AIF showed good agreement with the CEUS curves.
  
  
  CONCLUSIONS
  ICA has the potential to separate the intravascular component from DCE-MRI. This could eliminate the requirement for contrast medium uptake measurements in a major artery and potentially result in more accurate pharmacokinetic parameters.
  
  
  CONCLUSIONS
  • Tumour response to therapy can be inferred from pharmacokinetic parameters.                         • Arterial input function (AIF) is required for pharmacokinetic modelling of tumours.                         • Independent component analysis has the potential to measure AIF inside the tumour.                         • AIF measurement is validated using contrast enhanced ultrasound and phantoms.
authors: Department of Medical Biophysics, Sunnybrook Research Institute, University of Toronto, 2075 Bayview Avenue, Toronto, ON M4N 3M5, Canada. hatef.mehrabian@sri.utoronto.ca
authors: Hatef
authors: H
authors: Mehrabian
authors: Chaitanya
authors: C
authors: Chandrana
authors: Ian
authors: I
authors: Pang
authors: Rajiv
authors: R
authors: Chopra
authors: Anne L
authors: AL
authors: Martel
mesh_terms: D000465:Algorithms; D000818:Animals; D001158:Arteries / Q000473:pathology*; D003198:Computer Simulation; D003287:Contrast Media / Q000494:pharmacology*; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008279:Magnetic Resonance Imaging / Q000379:methods*; D015233:Models, Statistical; D019047:Phantoms, Imaging; D011817:Rabbits; D013997:Time Factors; D014463:Ultrasonography / Q000379:methods*
chemical_list: D003287:Contrast Media