Non-invasive characterization of intracranial tumors by magnetic resonance elastography

Abstract

Presurgical, non-invasive methods of differentiating brain tumors
\nhave remained unsatisfactory even for specialized academic hospitals. Despite
\nmajor advances in clinical and neuroradiological diagnostic techniques, the
\nmajority of neurooncology patients still need to undergo a brain biopsy for
\ndiagnosis. Recent single cell experiments suggested that biomechanical cell
\nproperties might be very sensitive in detecting cellular malignancy. Accordingly,
\nwe investigated magnetic resonance elastography (MRE) as an investigative tool
\nfor the clinical routine diagnostic work-up of intracranial neoplasm. In order
\nto obtain sufficient spatial resolution for the biomechanical characterization of
\nintracranial tumors, we modified a recently introduced least-squares solution of
\nthe stationary wave equation, facilitating stable solutions of the magnitude |G_|
\nand the phase angle ' of the complex shear modulus G_. MRE was added to a
\nroutine diagnostic or presurgical neuroradiological magnetic resonance imaging
\nwork-up in 16 prospective patients and it was well tolerated in all cases. Our
\npreliminary tumor MRE data revealed alterations in viscoelastic constants, e.g. a
\nloss of stiffness in malignancies compared to healthy reference tissue, or benign
\nvariants. Based on larger studies on selected tumor entities to establish threshold
\nand reference values for future diagnostic purposes, MRE may thus provide a
\npredictive marker for tumor malignancy and thereby contribute to an early noninvasive clinical assessment of suspicious cerebral lesions.