Fluorescein angiography for the detection of metastases of ovarian tumor in the abdominal cavity, a feasibility pilot

Background and Objectives: The growth and progression of ovarian tumor metastases at the peritoneal surfaces of the abdominal cavity are coupled with neovascularization. Newly formed tumor vessels show a more diffuse pattern and are more permeable for macromolecules than normal vessels. We investigated the possibility to detect (small) ovarian metastases in the abdominal cavity by means of fluorescein angiography. Study Design/Patients and Methods: Eighteen patients known with ovarian cancer or with suspicion for this disease received sodium fluorescein intravenously in different doses (0.4-1.6 ml of a 25% solution), whereafter fluorescence detection by laparoscope was carried out. The distribution pattern of fluorescein was gained from 0 to 120 min by pooling the data collected in different patients at various time intervals. Results: Three phases could be discriminated, that is, rapid filling of blood vessels after administration of fluorescein, diffuse extravasation of fluorescein into surrounding tissues, and clearance of fluorescein from vessels and surrounding tissue. Differences in accumulation of fluorescein could be visualized only after 1 hour or more. Fluorescence imaging more then 60 minutes after administration of fluorescein did not give additional information compared to the inspection using white light, which was confirmed by histology. These observations were dose-independent. Conclusions: The concentration gradient differences of fluorescein between healthy and pathological tissue in the abdominal cavity are too small to indicate tumor neovascularization.