ABSTRACT
BACKGROUND AND AIMS: Specialised intestinal metaplasia and its dysplastic transformation, which precedes cancer in Barrett's oesophagus cannot be differentiated in standard gastroscopy. The aim of this study was to investigate whether laser induced protoporphyrin IX fluorescence permits the detection of specialised intestinal metaplasia and dysplasia during endoscopy and to take biopsy specimens in a guided rather than random manner. METHODS: In 53 patients with Barrett's oesophagus 5-aminolaevulinic acid was sprayed on the mucosa. Approximately 60 to 120 minutes later, biopsy specimens were taken based on point-like measurements of delayed fluorescence intensity ratios of protoporphyrin IX in vivo. Two independent pathologists examined the 596 biopsy specimens taken, 168 of which were selected to be investigated by a third pathologist. Among these specimens only those (n=141) with a consensus diagnosis by at least two pathologists and p53 expression as additional marker were included in the analysis. RESULTS: The median of normalised fluorescence intensity (ratio of delayed PpIX fluorescence intensity to immediate autofluorescence intensity) in non-dysplastic specialised intestinal metaplasia (0.51, 68% CI 0.09 to 1.92) and low grade dysplasia (1.89, 68% CI 0.55 to 3.92) differed significantly (p<0.005). Dysplasia was detected at a rate 2.8-fold higher compared with screening endoscopy despite taking fewer specimens. In addition, three early cancers were detected for the first time. Moreover, this method permitted differentiation of specialised intestinal metaplasia from junctional or gastric-fundic type epithelium (p<0.013). CONCLUSIONS: For the first time it was possible to differentiate low grade dysplasia from non-dysplastic Barrett's mucosa during endoscopy based on delayed laser induced fluorescence endoscopy of PpIX. Furthermore, the method helps to detect specialised intestinal metaplasia in short Barrett's oesophagus.
Subject(s)
Adenocarcinoma/pathology , Barrett Esophagus/pathology , Esophageal Neoplasms/pathology , Esophagus/pathology , Precancerous Conditions/pathology , Adenocarcinoma/metabolism , Adult , Aged , Aged, 80 and over , Aminolevulinic Acid , Barrett Esophagus/metabolism , Biomarkers, Tumor/analysis , Biopsy/methods , Diagnosis, Differential , Esophageal Neoplasms/metabolism , Esophagus/chemistry , Female , Humans , Intestines/pathology , Male , Metaplasia/pathology , Middle Aged , Photosensitizing Agents , Precancerous Conditions/metabolism , Protoporphyrins/analysis , Signal Processing, Computer-Assisted , Spectrometry, Fluorescence/instrumentation , Spectrometry, Fluorescence/methods , Tumor Suppressor Protein p53/analysisABSTRACT
Optical mammography with near-infrared (NIR) light using time-domain, frequency-domain, or continuous-wave techniques is a novel imaging modality to locate human breast tumors. By investigating excised specimens of normal and diseased mamma tissue we were able to demonstrate that differences in their scattering properties are a poor predictive parameter for normal and diseased mamma tissue. This paper describes the application of a NIR dye to improve the differentiation between breast tumors and normal tissue in a rat model. The NIR dye furnished a high tumor-to-tissue contrast ratio (6:1) in fluorescence images. Furthermore, this dye was used to develop liquid scattering phantoms with absorbing and fluorescent inhomogeneities. Using frequency-domain and time-domain instrumentation these inhomogeneities were localized at sufficient contrast by their increased absorption and fluorescence. Contrast between inhomogeneities and surrounding medium could be improved by combining fluorescence and transmittance images.
Subject(s)
Breast Neoplasms/diagnosis , Carbocyanines , Contrast Media , Fluorescent Dyes , Infrared Rays , Mammography/methods , Optics and Photonics , Female , Humans , Phantoms, Imaging , Reference Values , Scattering, RadiationABSTRACT
We report here the in vivo diagnostic use of a peptide-dye conjugate consisting of a cyanine dye and the somatostatin analog octreotate as a contrast agent for optical tumor imaging. When used in whole-body in vivo imaging of mouse xenografts, indotricarbocyanine-octreotate accumulated in tumor tissue. Tumor fluorescence rapidly increased and was more than threefold higher than that of normal tissue from 3 to 24 h after application. The targeting conjugate was also specifically internalized by primary human neuroendocrine tumor cells. This imaging approach, combining the specificity of ligand/receptor interaction with near-infrared fluorescence detection, may be applied in various other fields of cancer diagnosis.
Subject(s)
Carbocyanines/metabolism , Carbocyanines/pharmacokinetics , Diagnostic Imaging/methods , Fluorescent Dyes/metabolism , Ligands , Microscopy, Fluorescence/methods , Neoplasms/pathology , Spectroscopy, Near-Infrared/methods , Animals , Cells, Cultured , Endocytosis , Flow Cytometry/methods , Humans , Mice , Mice, Nude , Microscopy, Confocal/methods , Neoplasm Transplantation , Plasmids/metabolism , Protein Binding , Rats , Time Factors , Tumor Cells, CulturedABSTRACT
Macromolecules accumulate in solid tumors and can thus be used as carriers for the delivery of attached contrast agents to tumors. We report the synthesis and use of serum protein-dye conjugates consisting of transferrin (Tf) or human serum albumin (HSA) and an indotricarbocyanine (ITCC) derivative as contrast agents for the optical imaging of tumors. The compounds were characterized with respect to their photophysical properties and tested in vitro for their ability to bind to tumor cells and in vivo for their potential to delineate experimental tumors. In contrast to HAS-ITTC, Tf-ITCC showed receptor-mediated uptake by HT29 human colon cancer cells in vitro. After intravenous injection into HT29 tumor-bearing nude mice both compounds induced increased fluorescence contrast of tumors in vivo. After 24 h the contrast between tumor and normal tissue was significantly higher for Tf-ITCC than for HAS-ITCC. Dye-induced fluorescence was found to be predominantly located in perinecrotic areas of the tumor. Furthermore, Tf-ITCC produced fluorescence of viable tumor cells, whereas HAS-ITCC fluorescence was recorded along connective tissue. We conclude that ITCC-labeled Tf and HSA can serve as macromolecular contrast agents for the optical imaging of tumors, with Tf-ITCC showing higher efficiency.
Subject(s)
Carbocyanines , Colonic Neoplasms/diagnosis , Animals , Contrast Media , Fluorescent Dyes , Humans , Macromolecular Substances , Mice , Mice, Nude , Serum Albumin , TransferrinABSTRACT
We have developed diffusely scattering solid phantoms with optical (scattering) properties amenable to theoretical calculations. Monodisperse quartz glass spheres were used as scatterers embedded in polyester resin. An infrared dye was added to simulate absorption by biological tissue. Solid phantoms were tested for their macroscopic homogeneity. Several phantoms were built with well-defined spatial variations in their transport scattering and absorption coefficients to be used for optical tomography. Scattering, transport scattering, and absorption coefficients of solid, homogeneous phantoms and of aqueous suspensions of monodisperse quartz glass spheres were derived from measurements of time-integrated collimated transmittance and time-resolved diffuse transmittance. For aqueous suspensions of monodisperse quartz glass spheres at known number density scattering and transport scattering coefficients calculated by Mie theory are in quantitative agreement with experimentally derived values. In addition, diffuse reflectance and diffuse transmittance of aqueous suspensions at various number densities were measured and found to be in excellent agreement with results of Monte Carlo calculations using theoretical values for the scattering coefficients and anisotropy parameters.
