Talk abstracts

Talk on Wednesday 04:15-04:30pm submitted by Wenbo Wei

Evaluation of Eye Metastatic Melanoma with Dynamic Contrast Enhanced-MRI

Wenbo Wei (Department of Radiology, The Ohio State University), Guang Jia (Department of Radiology, The Ohio State University), Frederick H. Davidorf (Department of Ophthalmology, The Ohio State University), Michael V. Knopp (Department of Radiology, The Ohio State University)

Abstract:
Malignant melanoma of the choroid is the most common intraocular malignancy in adults. Following treatment, by five years 30% of these patients will have died from metastasis. It is assumed that metastasis is via hematogenous spread. DCE MRI provides characteristic pharmacokinetic behavior of tumor vasculature. This study is to explore the capability of DCE MRI to determine patients with metastatic melanoma.7 patients with melanoma were scanned in a 3T MRI system. Biopsy was done after the scan. For dynamic analysis, a 3D fast field echo sequence was used. Magnevist was administered in a dose of 0.2ml/kg bodyweight with a rate of 0.6ml/s. The total acquisition time was 6:02 mins. The slice that centrally cut through the tumor was picked up for each patient. ROIs were drawn on the entire tumors. Brix two-compartment model was chosen and standardized AIF was used. Ktrans was calculated and compared between metastatic and non-metastatic melanoma using one-tailed unpaired t-tests. Results were considered to be significantly different when p<0.05. 3 patients were diagnosed with metastatic melanoma and 4 without from biopsy results. All tumors show measurable sizes in images (>5mm). A significant difference in Ktrans between patients with (0.5±0.2 min-1) and without (0.9±0.2 min-1) metastatic melanoma (p<0.05) was identified. The DCE-MRI data shows that the metastatic melanoma has lower blood transfer rate than the non-metastatic melanoma. Although the aggressive melanoma may produce more blood vasculature, it has fewer functional blood vessels and thus appears to be more poorly perfused with an overall decrease in blood exchange. It was shown that DCE-MRI can differentiate the tumor characterization between metastatic and non-metastatic melanoma. Thus, DCE-MRI has the potential to be an in-vivo imaging technique to predict early on which patients are prone to metastatic disease.

References:
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[7] Leenders W et. al. Int J Cancer 2003; 105:437-43.

Keywords: DCE-MRI, Metastatic Melanoma