Mapping local orientation of aligned fibrous scatterers for cancerous tissues using backscattering Mueller matrix imaging.

Polarization measurements are sensitive to the microstructure of tissues and can be used to detect pathological changes. Many tissues contain anisotropic fibrous structures. We obtain the local orientation of aligned fibrous scatterers using different groups of the backscattering Mueller matrix elements. Experiments on concentrically well-aligned silk fibers and unstained human papillary thyroid carcinoma tissues show that the m22 , m33 , m23 , and m32 elements have better contrast but higher degeneracy for the extraction of orientation angles. The m12 and m13 elements show lower contrast, but allow us to determine the orientation angle for the fibrous scatterers along all directions. Moreover, Monte Carlo simulations based on the sphere-cylinder scattering model indicate that the oblique incidence of the illumination beam introduces some errors in the orientation angles obtained by both methods. Mapping the local orientation of anisotropic tissues may not only provide information on pathological changes, but can also give new leads to reduce the orientation dependence of polarization measurements.

Immunohistochemical assessment of peroxidase-like immunoreactivity in the thyroid gland and its correlation with biochemical assay.

BACKGROUND: Peroxidase content has been recently evaluated in normal thyroid and in different thyroid disorders by biochemical, histochemical, ultrastructural and immunocytochemical methods. Nevertheless immunocytochemical detection of thyroid peroxidase in thyroid samples conventionally processed for histology has never been done using a commercially available antibody, neither its correlation with the biochemical activity on adjacent samples. METHODS: In this study we have analyzed normal thyroid tissue (3 patients), follicular adenoma (2 patients) and multinodular goiter (2 patients) conventionally processed for histology and stained by immunocytochemistry (Avidin Biotin System) using a polyclonal (rabbit) antibody for horseradish peroxidase (Serotec). Biochemical assay was performed on adjacent samples according to Hosoya method. RESULTS: Normal thyroid showed peroxidase immunoreactivity in the majority of follicular cells; neoplastic cells of adenomas were variably stained. Biochemical assay showed positive correlation with ICC ranging from 20.4 micrograms/mg/prot a in multinodular goiter to 42.12 in normal thyroid, up to 122 of follicular adenoma. CONCLUSIONS: Peroxidase content in the thyroid gland may be of clinical interest in several thyroid diseases, and in this study we have demonstrated that thyroid peroxidase can be detected by ICC in routinely processed thyroid samples using a commercially available antibody.

Cost-effectiveness analysis of somatostatin receptor scintigraphy.

UNLABELLED: We analyzed the results of conventional imaging and somatostatin receptor scintigraphy in 150 patients with neuroendocrine tumors. METHODS: The outcomes of combinations of imaging modalities were compared in terms of tumor localization, effect on patient management and financial costs. RESULTS: In patients with carcinoids, a combination of somatostatin receptor scintigraphy, chest radiograph and ultrasound of the upper abdomen had a high sensitivity for tumor localization, and detected lesions in patients in whom no tumor was found with conventional imaging, justifying the greater cost. In patients with medullary thyroid carcinoma, somatostatin receptor scintigraphy adds little to the information obtained with conventional imaging and therefore should not be used as a screening method. In patients with paraganglioma, CT scanning of the region where a paraganglioma is suspected, followed by somatostatin receptor scintigraphy to detect multicentricity has the best cost effectiveness ratio. In patients with gastrinomas, the combination of somatostatin receptor scintigraphy and CT scanning of the upper abdomen had the highest sensitivity. The relatively high cost of this process is outweighed by its demonstrating a resectable tumor. In patients with insulinomas, the highest yield against the lowest cost is obtained if somatostatin receptor scintigraphy is only performed if CT scanning fails to demonstrate the tumor. CONCLUSIONS: Somatostatin receptor scintigraphy should be performed in patients with small-cell lung carcinoma because it can lead to a change of stage and may demonstrate otherwise undetected brain metastases. The cost increase is outweighed by the omission of unnecessary treatment for some of the patients and by the possibility of irradiating brain metastases at an early stage, which may lead to a better quality of life.