MRI: PROMISING DENTAL APPLICATIONS THAT SUGGEST CLINICAL UTILITY

Abstract

Background Magnetic resonance imaging (MRI) research at the University of Minnesota has resulted in notable advancements, including capture of signal from densely calcified tissues. Application of this technology to address dental questions plus efforts to minimize the cost and size of MRI scanners suggests the potential adoption of MRI in regular clinical dental settings. Objective This abstract reviews advances in the areas that move this technology closer to adoption in dentistry: (1) capture of quickly decaying T2 signal, (2) coil development for dental applications, and (3) redesign of the MRI scanner for cost/size reductions. We present recent data suggesting that existing MRI technology can detect (cracks and blood flow within teeth. Materials and Methods Twenty-nine human teeth extracted after clinical diagnosis of a root crack/fracture were frequency matched to 29 control teeth. Teeth were scanned with MRI and cone beam computed tomography (CBCT). A 4-member panel evaluated the images according to established criteria. Saline was pumped through microtubing inserted into an extracted tooth to resemble pulpal blood flow. Flow rates were controlled within the range of calculated rates of pulpal arterioles. The setup was imaged with a sweep imaging with Fourier transformation (SWIFT)-MRI saturation technique to distinguish the moving fluid from surrounding stationary fluid. Results CBCT and MRI demonstrated similar levels of sensitivity and specificity, despite nonoptimized MRI image processing and limited observer calibration. Images with selective saturation of flowing or still liquids allowed for successful visualization of fluid-flow through the extracted tooth. Discussion Using improved pre- and postprocessing MRI approaches, teeth should be rescanned to enhance sensitivity of detecting cracks. Panelists should be educated and calibrated, and a reliability assessment study should be performed again with a larger sample size. Studies in extracted tooth flow imaging should be conducted to determine the lower limit of flow detection and whole-dentition in vivo images of vascular flow in teeth obtained.