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Radiology. 2012 Aug;264(2):436-44. Epub 2012 Jun 12.

Colon tumor growth and antivascular treatment in mice: complementary assessment with MR elastography and diffusion-weighted MR imaging.

Author information

1
Université Paris Diderot, Centre de Recherche Biomédicale Bichat Beaujon, Clichy, France. lauriane.juge@inserm.fr

Abstract

PURPOSE:

To investigate the potential value of magnetic resonance (MR) elastography and diffusion-weighted (DW) MR imaging in the detection of microstructural changes of murine colon tumors during growth and antivascular treatment.

MATERIALS AND METHODS:

The study was approved by the regional ethics committee for animal care. Sixty Balb-C mice, bearing ectopic and orthotopic colon tumors, were monitored for 3 weeks with high-resolution T2-weighted MR imaging, three-dimensional steady-state MR elastography, and DW MR imaging at 7 T. The same imaging protocol was performed 24 hours after injection of combretastatin A4 phosphate (CA4P) in 12 mice. The absolute value of the complex shear modulus (|G*|) and the apparent diffusion coefficient (ADC) were measured in the viable zones of tumors and compared with microvessel density (MVD), cellularity, and micronecrosis by using the Pearson correlation coefficient.

RESULTS:

During tumor growth, |G*| increase was correlated with MVD (r = 0.70 [P = .08] and r = 0.78 [P = .002], for both the ectopic and orthotopic models, respectively). Moreover, the ectopic tumors displayed decreased ADC, which correlated with increased cellularity (r = 0.77, P = .04), whereas no changes in ADC and cellularity were observed in orthotopic tumors. After CA4P administration, |G*| decreased in the ectopic model (P < .0001), similar to the MVD evolution (P = .03), whereas no significant changes in |G*| (P = .7) and MVD (P = .6) were observed in the orthotopic model. ADC increased in both models (P = .047 and P = .01 for the ectopic and the orthotopic models, respectively) in relation to increased micronecrosis.

CONCLUSION:

Imaging of mechanical properties and diffusivity provide complementary information during tumor growth and regression that are respectively linked to vascularity and tumor cell alterations, including cellularity and micronecrosis.

PMID:
22692038
DOI:
10.1148/radiol.12111548
[Indexed for MEDLINE]

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