A perfusion phantom with unique features and a wide variety of applications in MR and other imaging modalities is
presented. The phantom is especially suited for tissue perfusion simulation with diffusible and non-diffusible MR
tracers. A network of micro-channels in the scale of actual capillaries replicates the blood flow in tissues. Using
microfabrication techniques, networks with any desired pattern can be generated. Since the geometry of networks is
known, flow rate, delay, dispersion and other fluid parameters can be exactly calculated using finite elements numerical
methods. These calculated results can be used to investigate the accuracy of experimental measurements and the
precision of mathematical models.
Recent efforts in medical imaging have shown that mechanical stimulation of tissues and a suitable imaging modality can be used to interrogate elastic properties of human tissues. Malignant tissues can have elastic properties that allow the physician to separate them from benign counterparts or plaque in arteries can be characterized in regard to its age by measuring its elastic properties. Our system consists of: (1) an acoustic source to induce <i>tissue</i> displacement, (2) a tissue mimicking phantom, and (3) MRI as a method for imaging and measuring the induced shear wave in the phantom. Agar was used to construct a tissue mimicking phantom. A modified spin echo sequence was written to trigger the acoustic system and phase encode the displacement information with magnetic field gradients. A series of images was obtained from the modified multi-slice, spin-echo sequence. Images showed z-axis displacement created by the radiation force. Additional experiments recorded the x and y displacement and allowed for a full 3D vector reconstruction of shear wave propagation. MRI provides a method to record displacements created by radiation force. Acoustical sources can be used to induce shear waves, which in turn can be imaged with MRI methods to quantify and display this wave in a 3D fashion.