Rahul Anil Sheth BS, Presenter: Nothing to Disclose

Rabi Upadhyay BS, Abstract Co-Author: Nothing to Disclose

Ralph Weissleder MD, PhD, Abstract Co-Author: Board of Directors, VisEn Medical, Inc

Umar Mahmood MD, PhD, Abstract Co-Author: Consultant, VisEn Medical, Inc Stockholder, VisEn Medical, Inc

To determine the efficacy of a novel quantitative fiberoptic fluorescence imaging system for the detection and characterization of ovarian cancer metastases during laparoscopic evaluation of the abdomen.

A fiber optic catheter-based intravital imaging system that allows for the simultaneous and real-time visualization of white light (WL) and near infrared fluorescence (NIRF) was used to laparoscopically evaluate the abdomen of mice after orthotopic implantation of a murine ovarian cancer cell line (OVCAR3). Multiple foci of disease were visualized after administration of the protease-activatable probe ProSense (ViSen Medical, Woburn, MA), and fluorescence was quantified in real-time using a novel correction method that accounts for variations in signal intensity due to positional changes between the catheter and target lesion.

Primary and metastatic disease was visualized by NIRF imaging with high target to background ratios (> 4:1), including lesions not readily apparent by conventional WL evaluation. Moreover, whereas raw NIRF signal collected from individual lesions demonstrated a large (>200%) change from mean as the distance between the catheter tip and lesion was varied during the procedure, the corrected NIRF values remained relatively invariant (<10%) over the distance changes.

We have demonstrated the utility of NIRF imaging using protease-activatable probes towards the minimally invasive detection of ovarian cancer metastases. Moreover, we have applied a novel correction algorithm to account for a major drawback to intravital fluorescence imaging, namely, the inability to quantitate NIRF signal.

These results suggest optical imaging with molecular probes will play an important role in the improved detection and staging of ovarian cancer.

Sheth, R, Upadhyay, R, Weissleder, R, Mahmood, U, Quantitative Fiberoptic Fluorescence Imaging of Ovarian Cancer Metastases.  Radiological Society of North America 2007 Scientific Assembly and Annual Meeting, November 25 - November 30, 2007 ,Chicago IL. http://archive.rsna.org/2007/5014806.html