In Vivo Magnetic Resonance Imaging to Detect Malignant Melanoma in Adult Zebrafish

Abstract Zebrafish cancer models are fast gaining ground in cancer research. Most tumors in zebrafish develop late in life, when fish are no longer transparent, limiting in vivo optical imaging methods. Thus, noninvasive imaging to track tumor in adult zebrafish remains challenging. In this study, we applied magnetic resonance microimaging (μMRI) to track spontaneous melanomas in stable transgenic zebrafish models expressing an RAS oncoprotein and lacking P53 (mitf:Ras::mitf:GFP X p53−/−). Tumors in live adult zebrafish were observed at various locations using a T2-weighted fast spin echo sequence at 9.4 T. Further, live imaging of tumors at ultrahigh field (17.6 T) revealed significant tumor heterogeneity. This heterogeneity was also confirmed by the significant differences in transverse relaxation time, T2 measured in various regions of tumor. To our knowledge, this is the first report demonstrating the application of μMRI to detect the locations, invasion status, and characteristics of internal melanom...