Retinoblastoma: Value of Dynamic Contrast-Enhanced MR Imaging and Correlation with Tumor Angiogenesis

BACKGROUND AND PURPOSE: Noninvasive evaluation of retinoblastoma treatment response has become more important due to increased use of eye-sparing treatments. We evaluated the relation between DCE-MR imaging and histopathologic parameters to determine the value of DCE-MR imaging in assessing tumor angiogenesis and prognostic features.

MATERIALS AND METHODS: Fifteen consecutive patients with retinoblastoma (mean age, 24 months; range, 2–70 months) undergoing enucleation as the primary treatment (15 eyes) were scanned at 1.5T by using dedicated surface coils. Pretreatment DCE-MR imaging of the most affected eye was evaluated by 2 observers by using curve-pattern analysis, with the first 5 minutes of each curve and the full time-series described as κ_5min and κ_17min, respectively. Assessed histopathologic and immunologic parameters included optic nerve invasion, choroid invasion, MVD, tumor necrosis, and expression of VEGF and Flt-1.

RESULTS: The median value of κ_5min was 1.28 (range, 0.87–2.07) and correlated positively with MVD (P = .008). The median value of κ_17min was 1.33 (range, 0.35–3.08) and correlated negatively with tumor necrosis (P = .002). Other histopathologic and immunohistopathologic parameters did not correlate with DCE-MR imaging parameters. Interobserver agreement was 0.53 for κ_5min and 0.91 for κ_17min.

CONCLUSIONS: In retinoblastoma, the early phase of the DCE time curve positively correlates with MVD, while the presence of late enhancement is correlated with necrosis. Thus, the potential for DCE-MR imaging to noninvasively assess tumor angiogenesis and necrosis in retinoblastoma is promising and warrants further investigation.