Advanced magnetic resonance imaging biomarkers of cerebral metastases

Abstract

There are a number of magnetic resonance imaging techniques available for use in the diagnosis and management of patients with cerebral metastases. This article reviews these techniques, in particular, the advanced imaging methodologies from which quantitative parameters can be derived, the role of these imaging biomarkers have in distinguishing metastases from primary central nervous system tumours and tumour mimics, and metrics that may be of value in predicting the origin of the primary tumour.

Figure 1

Imaging appearances of a solitary mucinous metastases from a colonic carcinoma primary on (a) non-contrast CT (hyper-attenuating lesion); (b) T₂-weighted imaging (markedly hypointense); (c) T₁-weighted pre-contrast imaging (isointense); (d) post-gadolinium contrast T₁-weighted imaging (rim enhancement).

Figure 2

Imaging characteristics of melanoma metastases. (a) T₂; (b) pre-contrast T₁; (c) post-contrast T₁.

Figure 3

Perfusion imaging in (a) solitary cerebral metastasis and (b) GBM (axial imaging on the left and sagittal reformats on the right). Top row: T₂-weighted imaging. Middle row: post-contrast T₁-weighted imaging. Bottom row: CBV maps. Magnified images of CBV maps and corresponding T₂-weighted images. (a) The peri-lesional non-enhancing tissue surrounding the metastasis exhibits a very low relative CBV (white arrowhead) and represents vasogenic oedema; (b) the peri-lesional non-enhancing tissue surrounding the GBM has a slightly higher relative cerebral blood volume (white arrow) and represents infiltrating glioma.

Figure 4

Restricted diffusion in cerebral metastases. (a) T₂-weighted imaging; (b) post-contrast T₁-weighted imaging; (c) DWI; (d) ADC map. There is restricted diffusion within the medial aspect of the tumour which demonstrates restriction in the more solid, T₂ hypointense, non-enhancing component.