This recent article by Lavaud et al., uses high-frequency ultrasound and spectroscopic photoacoustic imaging as a multimodal non-invasive examination tool for the assessment of melanoma brain tumors in an orthotropic mouse model.
Article Summary:
- B16F10 murine skin melanoma cells were implanted orthotopically into the mouse brain
- Imaging of melanoma cells in tissue mimicking phantoms showed a linear correlation between PA signal and cell concentration, with a detection limit of 625 cells.
- 3D ultrasound and spectroscopic PA imaging were performed, looking at melanin, oxy and deoxy-hemoglobin.
- Both total hemoglobin content (HbT) and Oxygen saturation (SO2) were assessed
- Higher HbT values were observed in tumors compared to heathy brain of the same volume, whereas SO2 values were much lower in the tumors.
- A clear presence of melanin was detected, with 3 times higher PA signal compared to surround brain tissue.
- Further regional analysis showed much higher HbT and SO2 signals at the tumor periphery that decrease when moving towards the core.
Conclusion:
Photoacoustic (PA) imaging combines the advantages of high optical contrast and high ultrasound resolution at depth, to allow for non-invasive evaluations of endogenous contrasts. This enables non-invasive, contrast agent-free characterization of tumor vasculature and hypoxia, providing new opportunities for understanding cancer progression and treatment response.
Reference:
Lavaud, J., Henry, M., Coll, J. L. & Josserand, V. Exploration of melanoma metastases in mice brains using endogenous contrast photoacoustic imaging. Int. J. Pharm. 532, 704–709 (2017).
Avaible from: https://www.sciencedirect.com/science/article/pii/S0378517317308220?via%3Dihub