MRI applications often require high spatial and/or temporal resolution within a region of interest (ROI) such as for perfusion studies.
In theory, both spatial resolution and temporal resolution can be significantly improved using a ROI-focused MRI data acquisition
scheme. However, in radial MRI, there is no such acquisition-based solution available. Traditional reconstruction methods to image
the ROI by reducing the field of view produce aliasing artifacts when the dataset becomes truncated. Here we propose an interior
MRI methodology to perform ROI reconstruction without artifacts. Methods: In contrast to the conventional wisdom that the interior
problem does not have a unique solution, interior tomography has been recently proposed as an exact and stable solution to this longstanding
problem. In this project, a ROI-focused radial MRI data acquisition scheme was developed, aided by a dedicated digital
filter. We implemented this method in a 4T 90 cm bore Oxford magnet with a GE phantom and a transceiver TEM head coil. The
parameters were 4 gauss/cm sonata gradients, 5 mm slice thickness, TE=30 ms, TR=200 ms, FOVs of 40 cm and 12 cm respectively.
Results: Both numerical simulation and phantom experiments have demonstrated that the proposed interior MRI method can exactly
reconstruct a ROI with increased spatial resolution (~4 fold) while keeping the same temporal resolution. The image artifacts from
truncated projections are effectively eliminated. No crosstalk with the outside ROI region is involved using the proposed method.
Conclusions: Our interior radial MRI method can be used for zoomed-in and fast