1. Feature Of The Week 9/25/11: University of Maryland and NIH Researchers Investigate Combined OCT and Fluorescence Imaging for Improved Colon Cancer Detection

    Feature Of The Week 9/25/11: University of Maryland and NIH Researchers Investigate Combined OCT and Fluorescence Imaging for Improved Colon Cancer Detection

    Optical Coherence Tomography (OCT) offers high-resolution imaging of the tissue microstructure. But there are numerous limitations to OCT including providing direct molecular imaging capability. A popular recent research thrust has been to combine OCT with other imaging technology such as Raman, Fluorescence, and other molecular imaging techniques to achieve a multi-modality imaging capability. This multi-modality imaging offers improved capabilities including all the normal OCT and molecular imaging benefits as well as allowing the molecular imaging signals to be spatial registered within the tissue microstructure. This can lead to significant improvements in clinical capability including cancer detection. Researchers at the University of Maryland and the National Institute of Health have recently published interesting results on this topic. Below is a summary of their work on “combined optical coherence tomography and fluorescence molecular imaging for colon cancer detection”.

    Mutated adenomatous polyposis coli (APC) genes predispose neoplastic transformations in the bowel, progressing to colorectal carcinoma. Early detection facilitates clinical management and therapy. Novel lectin-mediated polymerized targeted liposomes (Rh-I-UEA-1), with polyp specificity and incorporated imaging agents were fabricated to locate and image adenomatous polyps in APCMin/+ mice. The biomarker α-L-fucose covalently joins the liposomal conjugated lectin Ulex europaeus agglutinin 1 (UEA-1) via glycosidic linkage to the polyp mucin. α-L-fucose has been reported to be over-expressed in the mucin of adenomatous polyps and could be a potential indicator for molecular targeting of polyps. Multispectral optical imaging (MSI) corroborated a global perspective of specific binding of targeted Rh-I-UEA-1 polymerized liposomes (rhodamine B Ex/Em 532/590–620 nm) to polyps with 1.4-fold labeling efficiency over normal mucosa. High-resolution, co-registered optical coherence tomography (OCT) and fluorescence molecular imaging (FMI) revealed the spatial correlation of contrast distribution and tissue morphology. Both modalities offered complimentary information pertaining to polyp detection. Rh-I-UEA-1 polymerized liposomes were applied topically to the lumens of freshly excised APCMin/+ bowels and the bowels were incubated with targeted liposomes (UEA-1 lectin), control liposomes (no lectin), or iohexol (Omnipaque) and imaged by the three techniques. Computed tomographic (CT) quantitative analyses did not confirm that targeted liposomes more strongly bound polyps than nontargeted liposomes or iohexol (Omnipaque) alone. OCT, that is able to reveal the tissue morphology, along with the co-registered FMI, substantiated Rh-I-UEA-1 liposome binding along the mucinous polyp surface. UEA-1 lectin denotes α-L-fucose biomarker carbohydrate expression at the mucin glycoprotein layer. These results suggest that Rh-I-UEA-1 polymerized liposomes bind to and reveal adenomatous polyps in APCMin/+ mice and that it could be a potential targeting agent for detection of colorectal carcinoma. With a multi-modal approach using OCT and FMI, anatomical features of the polyps as well as functional biomarkers can be imaged simultaneously and assessed conjointly for polyp identification at stages earlier than conventional colonoscopy.

    For more information see recent Article. Courtesy Yu Chen.  

     

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