- This work describes a method for incorporating patient data into a nutrient transport model of the intervertebral disc.This data was collected using MRI diffusion weighted imaging (DWI), and was converted into an apparent diffusion coefficient map (ADC map). This map was used to define the diffusion behavior of water within the nucleus pulposus (NP), a value which was then scaled to yield the diffusivities of the three primary solutes selected for this model: glucose, oxygen, and lactate. The results show distinct diffusion behavior between patients, even within discs of the same Pfirrmann grade. The importance of the distinct disc morphologies and physiological environments of each patient to the diffusion gradients in the disc is readily apparent. Patient-specific models could allow clinicians look for critical concentrations and pH’s in the patient’s discs (i.e. levels below which cells cannot survive). If levels are already low enough to indicate cell death, these patients would not be candidates for cell injection-based therapies. For patients without a dead zone -who are therefore candidates for cell therapy –the model can be used to determine proper dosing via iteratively increasing cell concentration until the patient develops a dead zone. This functionality indicates that patient-specific models could prove valuable in a clinical setting when predicting patient outcomes or treatment options.
- KEY WORDS: Intervertebral Disc (IVD), back pain, transport modeling, diffusion weighted imaging (DWI)