Can microplastics be visualised with MRI?

PURPOSE: Nanoplastics and microplastics (NMPs) are increasingly detected in human tissues. Currently, NMP tissue concentrations can only be detected using post-mortem, destructive techniques, severely limiting research into possible effects on the human body. Whether NMPs are MR-visible, and what implications NMPs have for medical imaging, remains unknown.

METHOD: The impact of NMPs on MR imaging was investigated by utilising a phantom containing several concentrations of NMPs, suspended in agar solution, as well as a phantom containing 3D-printed plastic (PETG) plastic flakes, similarly suspended in agar.

RESULTS

While NMPs were not apparent on clinical T1 and T2 weighted scans, NMP aggregates were observed on magnetic susceptibility (T2∗ weighted) scans, appearing as hypointensities. Susceptibility-weighted imaging and computational modelling show that NMP aggregates create localised magnetic field inhomogeneities, acting as magnetic susceptibility dipoles and appearing as millimetre-sized hypointensities on T2∗ images.

CONCLUSIONS

NMP aggregates are detectable on T2∗ MR imaging and may potentially complicate the clinical interpretation of MR images.