We wanted to show various MR and correlated pathologic images of retinoblastoma in nude mousewith a new human retinoblastom cell line (SNUOT-Rb1), which was inoculated into the intravitreous cavity.

The established cell line was inoculated into the intravitreous cavity of 36 eyeballs of 18 mice and the transplanted retinoblastoma was examined for 3 months. The T1-weighted (T1WI), T2-weighted (T2WI), and contrast enhanced (Gd-DTPA) T1-weighted images were obtained with using a small loop coil. After scanning, the mice's eyeballs were extracted and the hematoxylin & eosin stained specimens were examined with a microscope. We compared the MR imagings with pathologic findings and evaluated the character of the tumors.

The innoculated cells in the eyeballs of the mice grew into retinoblastoma (23/36, 64%). The eyeballs with retinoblastoma protruded externally and showed focal hemorrhage. Most tumors showed iso-signal intensity on TIWI (13/23, 57%), high signal intensity on T2WI (17/23, 74%), and good enhancement (21/23, 91%) with contrast. Almost all of the tumors (n=21) were located in the retina and three extraretinal tumors were confirmed by pathology. Involvement of the optic nerve was suspected on MRI and this was confirmed by pathology in 6 cases and 5 cases, respectively.

We could demonstrate various MR imagings of transplanted retinoblastoma by using the new tumor cell line in vivo.