Optical coherence tomography for rapid tissue screening and directed histological sectioning

In pathology, histological examination of the tissue is the "gold standard" to diagnose various diseases. It has contributed significantly toward identifying the abnormalities in tissues and cells, but has inherent drawbacks when used for fast and accurate diagnosis. These limitations include the lack of in vivo observation in real time and sampling errors due to limited number and area coverage of tissue sections. Its diagnostic yield also varies depending on the ability of the physician and the effectiveness of any image guidance technique that may be used for tissue screening during excisional biopsy. In order to overcome these current limitations of histology-based diagnostics, there are significant needs for either complementary or alternative imaging techniques which perform non-destructive, high resolution, and rapid tissue screening. Optical coherence tomography (OCT) is an emerging imaging modality which allows real-time cross-sectional imaging with high resolutions that approach those of histology. OCT could be a very promising technique which has the potential to be used as an adjunct to histological tissue observation when it is not practical to take specimens for histological processing, when large areas of tissue need investigating, or when rapid microscopic imaging is needed. This review will describe the use of OCT as an image guidance tool for fast tissue screening and directed histological tissue sectioning in pathology.

Prospective evaluation of optimal number of biopsy specimens and brush cytology in the diagnosis of cancer of the colorectum

We prospectively studied the diagnostic accuracy of endoscopic biopsy and cytology in the diagnosis of colorectal cancer and sought to ascertain the optimal number of biopsy specimens that should be taken. Seventy consecutive patients with colorectal masses or polypoid lesions that could not be removed by endoscopic polypectomy and which were referred for surgery were studied. Lesions were first brushed for cytology. A series of 10 biopsies were then obtained from each lesion; the first four were placed into the first container, and two were placed into each of three other containers. Cytology and biopsies were read blindly by one pathologist. Findings were compared with the resection specimen results. Ten lesions were benign; all had negative biopsies and cytology. Sixty lesions were malignant: cytology was positive in 77.2% and biopsies in 78.3%. The yield was increased to 91.7% when both were done (cytology plus six biopsies). Cytology detected seven cancers that were missed by biopsy. Biopsy detected eight cancers not diagnosed by cytology. Five cancers were missed by both. Of the 47 cancers detected by biopsy, the first four biopsies made the diagnosis in 41 cases. Taking two more biopsies (six total) identified six more cancers. No additional cancers were identified by taking more biopsies (eight or 10 total). When six different biopsy-cytology strategies were examined: 1) cytology alone, 2) four biopsies (Bx), 3) six Bx, 4) 10 Bx, 5) cytology + four Bx, and 6) cytology + six Bx, the yield was 77.2%, 68.3%, 78.3%, 78.3%, 90.0%, and 91.7%, respectively. We conclude that biopsy and cytology are complementary in the diagnosis of colorectal cancer. The combination of cytology and four to six biopsies is recommended. There appears to be little additional yield to taking more than six biopsies. Even combined biopsy and cytology will miss 8-10% of cancers.

Logical classifiers for image analysis in medicine

A simple, intuitive procedure for the stepwise classification of objects in n-dimensional feature spaces is presented. Each classification step is based on a single feature decision and provides an optimal separation of the objects of only one class from the objects of all other classes. The algorithm of this procedure is implemented on a minicomputer of an image-analysis system. Testing of the classifiers on biomedical data (213 slides of diseased and normal liver tissue) yielded good results requiring few decisions and threshold parameters: 152 correct classifications, 16 incorrect classifications and 45 rejections.

[Possibility of using cytofluorometers to determine the ratio between normal and neoplastic cells]

Principal possibility to use the pulsatile flowtype cytofluorometers for recording nontypical cells in biopsy material and the whole blood is considered.

[The cytocentrifuge in cerebrospinal fluid cytodiagnosis]

Cytocentrifugation enables high-quality liquor preparations rich in cells to be obtained, offering certain advantages over Sayk's sediment chamber method.

High-quality cell block preparation from scraping of conventional cytology slide: a technical report on a modified cytoscrape cell block technique

BACKGROUND

Immunocytochemistry (ICC) on formalin-fixed paraffin embedded cell blocks is an ancillary tool commonly recruited for differential diagnoses of fine needle aspiration cytology (FNAC) samples. However, the quality of conventional cell blocks in terms of adequate cellularity and evenness of distribution of cytologic material is not always satisfactory for ICC. We introduce a modified agarose-based cytoscrape cell block (CCB) technique that can be effectively used for the preparation of cell blocks from scrapings of conventional FNAC slides.

METHODS

A decoverslipped FNAC slide was mounted with a small amount of water. The cytological material was scraped off the slide into a tissue mold by scraping with a cell scraper. The cytoscrape material was pelleted by centrifugation and pre-embedded in ultra-low gelling temperature agarose and then re-embedded in conventional agarose. The final agarose gel disk was processed and embedded in paraffin.

RESULTS

The quality of the ICC on the CCB sections was identical to that of the immunohistochemical stains on histological sections. By scrapping and harvesting the entirety of the cytological material off the cytology slide into a compact agarose cell button, we could avoid the risk of losing diagnostic material during the CCB preparation.

CONCLUSION

This modified CCB technique enables concentration and focusing of minute material while maintaining the entire amount of the cytoscrape material on the viewing spot of the CCB sections. We believe this technique can be effectively used to improve the level of confidence in diagnosis of FNAC especially when the FNAC slides are the only sample available.

[Evaluation of capability of cell count and detection of tumor cells in cerebrospinal and body fluids by automated hematology analyzer]

Sysmex XE-5000 offers the body fluid modus which provides the opportunity to count and differentiate leukocytes in body fluids and cerebrospinal fluid (CFS). In this study, we evaluated the basic performance of this application using routinely obtained samples in comparison with manual counting. Reproducibility study yielded good results in samples with a high white blood cell (WBC) count, whereas relatively high imprecision was observed at low WBC counts. Linearity was established up to 1,500 cells/microL in CFS and 5,600 cells/microL in body fluid. The cell count by XE-5000 was highly correlated with that of the microscopic reference method. Highly fluorescent body fluid cells percent (HF-BF%) was observed in samples with tumor cells or activated macrophages, which provides information about the possible presence of tumor cells. In conclusion, total and differential WBC counts in body fluid and CFS can be reliably determined by XE-5000 in samples with increased cell counts. XE-5000 also provides screening information about the presence of tumor cells for further manual examination.

Real-time pathology through in vivo microscopy

Miniature microscopes are being developed to examine tissue in situ for early anatomic and molecular indicators of disease, in real time, and at cellular resolution. These new devices will lead to a shift from the current diagnostic paradigm of biopsy followed by histopathology and recommended therapy, to one of non-invasive point-of-care diagnosis with the possibility of treatment in the same session. This potential revolution in disease management may have a major impact on the training of future physicians to include the use and interpretation of real-time in vivo microscopic data, and will also affect the emerging fields of telepathology and telemedicine. Implementation of new technologies into clinical practice is a complex process that requires multidisciplinary communication and collaboration among clinicians, engineers and scientists. As such, our aim is to provide a forward-looking view of the critical issues facing the development of new technologies and directing clinical education. Here, we focus on the use of in vivo microscopy for detection of malignant and pre-malignant lesions as well as for guiding therapy. We will highlight some of the areas in which in vivo microscopy could address unmet clinical needs, and then review the technological challenges that are being addressed, or need to be addressed, for in vivo microscopy to become an effective clinical tool.

Replica cytology in cancer of the larynx: an evaluation of a replica method in the diagnosis of laryngeal malignancy

A series of 38 cytological samples from the larynx, obtained with a replica method, is presented. The method is described in detail. Conclusive material was obtained in 34 cases. Fourteen per cent false negative evaluations were found. However, when more strict criteria were used for accepting the cytological specimen as suitable for evaluation, no false negative was encountered. It is therefore concluded that this replica method for obtaining cytological samples from the larynx could become a valuable tool as a screening method during indirect laryngoscopy in search of laryngeal malignancy provided very strict criteria are used for accepting the cytological specimen as suitable for evaluation.

Ontology-based lymphocyte population description using mathematical morphology on colour blood images

Despite modern technologies (immunophenotyping, molecular probing, etc.) cytomorphologic examination of stained peripheral blood smears by microscopy remains the main way of diagnosis in a large variety of diseases (e.g. leukaemic disorders). Using tools from mathematical morphology for processing peripheral blood colour images, we have developed an image-based approach, to provide an objective and understandable description of lymphocyte populations according to a specifically designed ontology. This ontology-based framework needs a conceptualisation of the problem from a morphological viewpoint, the introduction of an adapted language, the generation of representative image databases, the development of image processing and data classification algorithms to automate the procedure and the validation of the system by human expertise. In this paper we present the main concepts, algorithms and some results to illustrate the high-performance of the approach. The aim of our work is to reconcile the automatisation with the medical expertise, so that they can reinforce each other.