Simultaneous interpretation of preoperative, working length and post-treatment radiographs is important when attempting to diagnose a C-shaped configuration.

The evaluation of fluorescent in situ hybridization (FISH) images is one of the most widely used methods to determine Her-2/neu status of breast samples, a valuable prognostic indicator. Conventional evaluation is a difficult task since it involves manual counting of dots in multiple images. In this paper, we present a multistage algorithm for the automated classification of FISH images from breast carcinomas. The algorithm focuses not only on the detection of FISH dots per image, but also on combining results from multiple images taken from a slice for overall case classification. The algorithm includes mainly two stages for nuclei and dot detection respectively. The dot segmentation consists of a top-hat filtering stage followed by template matching to separate real signals from noise. Nuclei segmentation includes a nonlinearity correction step, global thresholding to identify candidate regions, and a geometric rule to distinguish between holes within a nucleus and holes between nuclei. Finally, the marked watershed transform is used to segment cell nuclei with markers detected as regional maxima of the distance transform. Combining the two stages allows the measurement of FISH signals ratio per cell nucleus and the collective classification of cases as positive or negative. The system was evaluated with receiver operating characteristic analysis and the results were encouraging for the further development of this method.

Intracoronal bleaching of nonvital, teeth with 30% hydrogen peroxide is occasionally associated with external cervical root resorption. The exact mechanism by which bleaching induced root resorption occurs is not yet fully understood. The relationship of cementum to the enamel at the cementoenamel junction may have clinical significance. Seventeen single rooted human mandibular premolars extracted atraumatically for orthodontic reasons were used. The radicular hydrogen peroxide penetration in each tooth was measured in vitro by an indirect colorimetric method. Thereafter, the teeth were examined with a scanning electron microscope to determine the type of the cementoenamel junction. It was found that the radicular penetration of 30% hydrogen peroxide was related to the type of cementoenamel junction.

The purpose of this study was to evaluate the suitability of a digital radiograph registration and subtraction software for a sensitive and reliable assessment of the progress of chronic apical periodontitis. Ninety cases of teeth with chronic apical periodontitis have been studied. In each case, a preoperative radiograph was taken, root canals were prepared, and a Ca(OH)2 paste was placed in the root canals. Radiographic control and replacement of Ca(OH)2 paste took place at 15-day intervals. The root canals were obturated 1.5 months after the first appointment. Recall radiographs were taken 0.5, 1.5, 3, 6, and 12 months after the obturation. All radiographs were taken for each case under constant conditions by using a direct digital radiography system. In each case, the preoperative, postoperative, and control and recall radiographs were digitally registered and pairwise subtracted. The resulting images were further processed by using contrast enhancement and pseudocoloring methods. Changes to the periapical tissue structure were easily detectable by using the above-mentioned methodology, even during short time intervals.

Fluorescent in-situ hybridization (FISH) and immunohistochemistry (IHC) constitute a pair of complimentary techniques for detecting gene amplification and overexpression, respectively. The advantages of IHC include relatively cheap materials and high sample durability, while FISH is the more accurate and reproducible method. Evaluation of FISH and IHC images is still largely performed manually, with automated or semiautomated techniques increasing in popularity. Here, we provide a comprehensive review of a number of (semi-) automated FISH and IHC image processing systems, focusing on the algorithmic aspects of each technique. Our review verifies the increasingly important role of such methods in FISH and IHC; however, manual intervention is still necessary in order to resolve particularly challenging or ambiguous cases. In addition, large-scale validation is required in order for these systems to enter standard clinical practice. q 2007 International Society for Analytical Cytology Key terms: fluorescent in situ hybridization (FISH); immunohistochemistry (IHC); image analysis techniques; nuclei segmentation; spot detection; antibody staining A variety of methods are available for the detection of gene status in tissue samples, with fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC) being two of the most prominent ones for detecting gene amplification and overexpression, respectively. Both techniques permit the study of small amounts of formalinfixed, paraffin-embedded tissue and the interpretation of the findings on a cell-by-cell basis. FISH allows selective staining of various DNA sequences with fluorescent markers, and thereby the detection, analysis, and quantification of specific numerical and structural abnormalities within nuclei. This procedure has proven to be as accurate as Southern blot analysis, while allowing the measurement of the fraction of amplified cells and the intercellular heterogeneity within a given cell population (1,2). On the other hand, IHC uses specific antibodies to stain proteins in situ, which allows the identification of many cell types that could be visualized by classical microscopy.FISH is a direct in situ technique that is relatively rapid and sensitive. No cell culture is needed to apply this method and results are easier to interpret than karyotype. The FISH technique has the advantages of a more objective scoring system and the presence of a built-in internal control consisting of the two Her-2/neu gene signals present in all nonneoplastic cells of the specimen. Disadvantages of FISH testing include the high cost of each test, long time needed for slide scoring, requirement for a fluorescence microscope, inability to preserve the acquired sample for storage and review, and, occasional difficulty in identifying the invasive tumor cells (3). On the other hand, advantages of IHC testing include its wide availability, relatively low cost, easy and long preservation of stained slides, and use of an ordinary light microscope. Disadvantages of IHC include the...