Spatiotemporal quantification of local drug delivery using MRI

Area of Science:

• Biomedical Engineering
• Medical Imaging
• Pharmacology

Background:

• Controlled release drug delivery is crucial for localized treatments.
• In vivo characterization of drug distribution remains challenging.
• Magnetic Resonance Imaging (MRI) offers potential for non-invasive in vivo monitoring.

Purpose of the Study:

• To develop and validate an in vivo MRI method for visualizing and quantifying local drug delivery.
• To assess the spatial and temporal distribution of MRI contrast agents in vivo.
• To compare different image processing techniques for drug delivery quantification.

Main Methods:

• In vivo MRI was used to acquire T1-weighted images with varied repetition times (TR).
• Three-dimensional T1 maps were generated and processed using noise-reducing filters.
• Contrast agent concentration was calculated from T1 maps using a simplified equation, avoiding image registration.

Main Results:

• The developed MRI technique successfully visualized and quantified the time-resolved distribution of contrast agents in vivo.
• A method using a uniform precontrast T1 (T1,0) value proved practical and effective, eliminating the need for image registration.
• Error estimations were performed at each processing step to ensure reliability.

Conclusions:

• This in vivo MRI approach provides a valuable tool for characterizing local drug delivery from controlled release formulations.
• The simplified quantification method enables accurate assessment of drug distribution over time.
• This technique can significantly advance the development and optimization of localized drug delivery systems.