Parametric imaging of tumor perfusion using flow- and permeability-limited tracers.
OBJECTIVE
To quantitatively evaluate the spatial distribution of flow- and permeability-limited perfusion in MCF7 human breast cancer tumors orthotopically implanted in CD1-NU mice.


METHODS
Flow-limited perfusion was derived from (2)H-MRI recorded before and after infusion of deuterated water. Permeability-limited perfusion was evaluated from GdDTPA-enhanced (1)H-MRI.


RESULTS
The dominant processes in tumor perfusion, namely blood flow and capillary permeability, were mapped in orthotopically implanted MCF7 human breast cancer tumors. The dynamic data were processed according to physiological models, yielding parametric maps of intravascular volume fraction, water perfusion rate, GdDTPA permeability rate constant, and extracellular volume fraction accessible to GdDTPA. The maps exhibited the heterogeneous distribution of each perfusion parameter. Most of the tumor tissue (> or =95%) was perfused with HDO, while GdDTPA was perfused in only about 50% of it. In most loci the perfusion rate was limited by capillary permeability to GdDTPA.


CONCLUSIONS
The results demonstrated the instructive value of tracers with different properties used in conjunction to achieve a deeper understanding of tumor perfusion capacity. This study offers tools for the accurate, noninvasive evaluation of drug delivery efficacy.
Department of Biological Regulation, Weizmann Institute of Science, Rehovot, Israel.
Liora
L
Bogin
Raanan
R
Margalit
Joel
J
Mispelter
Hadassa
H
Degani
D000818:Animals; D001943:Breast Neoplasms / Q000098:blood supply / Q000175:diagnosis*; D002199:Capillary Permeability; D003287:Contrast Media; D003903:Deuterium; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010477:Perfusion; D014407:Tumor Cells, Cultured
D003287:Contrast Media; D003903:Deuterium; D019786:Gadolinium DTPA