MRI of Fluid Flow Inside Teeth using Custom Head Phantom

Objectives: Accuracy of current methods to assess pulpal status of teeth, such as temperature and electricity, is lacking due to variation in patient response and provider interpretation. In this project, magnetic resonance imaging (MRI) is investigated as a potential means to bring objectivity to the pulpal diagnosis. Previous work showed that MRI could be used to detect flow within pulp of an extracted tooth. To further the research, a phantom filled with fluid to resemble the anatomical geometry and tissues of the human head was developed and utilized for closer resemblance to in vivo conditions.
Methods: 0.256 mm polytetrafluoroethylene micro tubing was inserted in U-shape inside extracted teeth, fixed within the 3D-printed head phantom. 0.9% saline was pumped at controlled speed through the tubing, modeling bulk pulpal blood flow. 4T MRI interfaced to Agilent DirectDrive console with the intraoral dental coil was performed on the phantom containing 4 teeth with the inserted tubing through the apical and 4 teeth without. MRI SWeep Imaging with Fourier Transformation (SWIFT) along with blood inflow slab saturation technique was used. All acquisition parameters were identical to those intended to be used for in vivo imaging.
Results: Preliminary result with fluid controlled at velocity 8 times higher than the reported velocity of blood flow within the pulpal arteriole showed distinction between teeth with flowing fluid within the pulp and teeth without such flow. The scanning time was 210 seconds.
Conclusions: Continued refinement of MRI pulse sequence, artifact correction, and other image parameters is anticipated to improve detection of flow velocities similar to the reported velocity of blood flow in teeth. This bulk flow model of fluid flow in teeth mimics in vivo condition.