title: Non-invasive in vivo mapping of tumour vascular and interstitial volume fractions.
abstract: Non-invasive measurement of haemodynamic parameters and imaging of neovasculature architecture is of importance in determining tumour prognosis, in directing tissue sampling and in assessing treatment efficacy. In the current research we investigated a dual tracer nuclear magnetic resonance (NMR) technique to map the tumour vascular (VVF) and interstitial volume fraction (IVF) non-invasively in vivo. We hypothesised that a NMR signal emanating after intravenous administrations of a vascular paramagnetic probe (MPEG-PL-GdDTPA) can be maximised so that additional signal after administration of a second interstitial probe (GdDTPA) would only reflect the IVF but not the VVF. The method and its assumptions were verified and experimental conditions optimised both in phantoms and in C6 glioma bearing rats. Data derived from in vivo studies show tumoral VVF and IVF values that are consistent with histology data and literature values; the relative ranking order of values was tumour > muscle > brain. Image maps showed intratumoral and intertumoral heterogeneity of both parameters at submillimetre pixel resolution. The method is applicable to a wide variety of tumour models and can theoretically be performed repeatedly to study tumour growth or involution during therapy.
authors.affiliation: Center for Molecular Imaging Research, Massachusetts General Hospital, Charlestown 02129, USA.
authors.forename: R
authors.initials: R
authors.lastname: Weissleder
authors.forename: H C
authors.initials: HC
authors.lastname: Cheng
authors.forename: E
authors.initials: E
authors.lastname: Marecos
authors.forename: K
authors.initials: K
authors.lastname: Kwong
authors.forename: A
authors.initials: A
authors.lastname: Bogdanov
mesh_terms: D000818:Animals; D001932:Brain Neoplasms / Q000098:blood supply*; D002199:Capillary Permeability / Q000502:physiology; D003287:Contrast Media; D005260:Female; D019786:Gadolinium DTPA; D005910:Glioma / Q000098:blood supply*; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D009368:Neoplasm Transplantation; D009389:Neovascularization, Pathologic / Q000175:diagnosis*; D051381:Rats
chemical_list: D003287:Contrast Media; D019786:Gadolinium DTPA