Image filtering techniques for medical image post-processing: an overview.
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Algorithms↗
Biomedical subjects
F J Leong
Publications and source records attributed to F J Leong.
Fusion of contrast-enhanced breast MR and mammographic imaging data.
Increasing use is being made of Gd-DTPA contrast-enhanced MRI (CE-MRI) for breast cancer assessment since it provides three-dimensional (3D) functional information via pharmacokinetic interaction between contrast agent and tumour vascularity, and because it is applicable to women of all ages as well as patients with post-operative scarring. CE-MRI is complementary to conventional X-ray mammography, since it is a relatively low-resolution functional counterpart of a comparatively high-resolution 2D structural representation. However, despite the additional information provided by MRI, mammography is still an extremely important diagnostic imaging modality, particularly for several common conditions such as ductal carcinoma in situ (DCIS) where it has been shown that there is a strong correlation between microcalcification clusters and malignancy. Pathological indicators such as calcifications and fine spiculations are not visible in CE-MRI and therefore there is clinical and diagnostic value in fusing the high-resolution structural information available from mammography with the functional data acquired from MRI. This article is a clinical overview of the results of a technique to transform the coordinates of regions of interest (ROIs) from the 2D mammograms to the spatial reference frame of the contrast-enhanced MRI volume. An evaluation of the fusion framework is demonstrated with a series of clinical cases and a total of 14 patient examples.
Breast Neoplasms↗
Automated complete slide digitization: a medium for simultaneous viewing by multiple pathologists.
Developments in telepathology robotic systems have evolved the concept of a 'virtual microscope' handling 'digital slides'. Slide digitization is a method of archiving salient histological features in numerical (digital) form. The value and potential of this have begun to be recognized by several international centres. Automated complete slide digitization has application at all levels of clinical practice and will benefit undergraduate, postgraduate, and continuing education. Unfortunately, as the volume of potential data on a histological slide represents a significant problem in terms of digitization, storage, and subsequent manipulation, the reality of virtual microscopy to date has comprised limited views at inadequate resolution. This paper outlines a system refined in the authors' laboratory, which employs a combination of enhanced hardware, image capture, and processing techniques designed for telepathology. The system is able to scan an entire slide at high magnification and create a library of such slides that may exist on an internet server or be distributed on removable media (such as CD-ROM or DVD). A digital slide allows image data manipulation at a level not possible with conventional light microscopy. Combinations of multiple users, multiple magnifications, annotations, and addition of ancillary textual and visual data are now possible. This demonstrates that with increased sophistication, the applications of telepathology technology need not be confined to second opinion, but can be extended on a wider front.
Analog-Digital Conversion↗
Practical applications of Internet resources for cost-effective telepathology practice.
Telepathology is the interpretation of digital microscopy images on a computer monitor at a significant distance from the location of original histology slides. Its use has proliferated globally and is part of routine practice in many laboratories. Even so, many perceive telepathology as requiring heavy initial capital expenditure. However, telepathology may be implemented in a wide variety of ways, some inexpensive. The limiting factor is often the technical knowledge and skill of the pathologist, not the technology or economics. The Internet is a versatile medium that may act as a repository of information in telepathology or as a communication conduit for either real-time (dynamic or robotic) or store-and-forward (static) methods. PubMed is an excellent starting point for literature research, with many journals providing full versions of their articles online to subscribers. However, these are largely in other fields of medicine and good online resources dedicated to telepathology techniques and information are less easily found. As a conduit for communication, the Internet can be the most economical option. Nearly every form of telepathology may use the Internet, provided there is sufficient bandwidth. Several techniques applied to general imaging may be used in store-and-forward telepathology. This article outlines some examples and discusses their relative merits.
Cost Control↗
Clinical trial of telepathology as an alternative modality in breast histopathology quality assurance.
Telepathology is a potential alternative to conventional histopathology. A clinical trial using a robotic telepathology system was conducted to assess the clinical and technical utility and effectiveness of telepathology in the U.K. breast screening pathology quality assurance program. Eighty-seven cases of breast disease were chosen at random from a series of 192 cases from the U.K. Breast Screening Pathology National Quality Assurance Scheme (NEQAS) collection. There were 20 benign, 23 carcinoma in situ (CIS), and 44 invasive malignant cases. The diagnostic accuracy of telepathology (TP) compared with conventional light microscopic (LM) diagnosis was 98.8%; this included a single case deferred for LM examination. The figure was similar when compared with expert consensus diagnosis (CD). In invasive tumor typing, TP accuracy was 95.4% (42/44 cases), the difference being attributable to slide color fading and would have had no impact on patient management. The accuracy of TP versus LM and expert consensus in tumor grading was 91.3% for carcinoma in situ (21/23 cases), a discordance with no relevance to patient management. TP grading of invasive tumor compared with LM diagnosis, had an accuracy of 86.4% (38/44) with a clinically significant accuracy of 97.7% (43/44). The time taken for TP diagnosis averaged 3.9 minutes per case by the end of the study. This data demonstrates that telepathology diagnostic accuracy is comparable to conventional microscopy and may therefore be envisaged as an alternative to conventional light microscopy for more rapid proficiency testing in breast screening (and perhaps other) quality assurance schemes.
Biopsy↗
What we need to know about cancer genes.
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Cell Adhesion Molecules↗
Verruciform xanthoma of the vulva. A case report.
Verruciform xanthoma is a benign lesion of the oral cavity and skin, which is characterized by aggregates of bland foamy histiocytes (xanthoma cells) within the connective tissue and underlying acanthotic, parakeratotic hyperplastic epithelium with elongated rete ridges. We describe a rare case of vulval verruciform xanthoma in an 84-year-old, which was clinically mistaken for malignant tumor. Immunohistochemistry confirmed the histiocytic nature of the foamy cells and electron microscopy showed the cytoplasmic vacuoles to contain lipid. A finding as yet undocumented in the literature was the presence of foamy histiocytes within the draining lymph nodes. This case highlights clinical mimicry of a malignant tumor by anogenital verruciform xanthoma.
Aged↗
Malignant rhabdoid tumor in adults--heterogenous tumors with a unique morphological phenotype.
Five cases of malignant rhabdoid tumors in adult patients are described. The tumors were characterized by sheets of poorly cohesive cells with distinctive hyaline cytoplasmic inclusions and eccentrically placed large vesicular nuclei with prominent nucleoli. A variety of lineage differentiation was shown by immunohistochemistry and electron microscopy, the lesions representing leiomyosarcoma, gastric carcinoma, epithelioid sarcoma, Merkel cell carcinoma and desmoplastic small round cell tumor. Previously reported cases of rhabdoid tumors in adults support the contention that such tumors, although of distinctive morphologic phenotype, are of heterogenous lineage differentiation, and do not represent a distinct clinicopathologic entity.
Adult↗
Signet-ring carcinoma of the prostate.
A case of prostatic signet-ring adenocarcinoma is described in a man with a history of open prostatectomy for prostate carcinoma (18 years previously). Immunostaining confirmed the prostatic origin of the signet-ring tumor which stained for prostatic acid phosphatase (PSAP) and prostate specific antigen (PSA). Cytokeratin immunostaining showed the vacuoles to be true lamina with clear and distinct outlines, the feature confirmed by ultrastructural examination. This aggressive tumor is an uncommon but distinct variant of primary prostatic carcinoma which should be distinguished from artefactual vacuolation of tumor, inflammatory and stromal cells, and metastatic disease.
Aged↗
Digital photography in anatomical pathology.
Digital imaging has made major inroads into the routine practice of anatomical pathology and replaces photographic prints and Kodachromes for reporting and conference purposes. More advanced systems coupled to computers allow greater versatility and speed of turnaround as well as lower costs of incorporating macroscopic and microscopic pictures into pathology reports and publications. Digital images allow transmission to remote sites via the Internet for consultation, quality assurance and educational purposes, and can be stored on and disseminated by CD-ROM. Total slide digitisation is now a reality and will replace glass slides to a large extent. Three-dimensional images of gross specimens can be assembled and posted on websites for interactive educational programmes. There are also applications in research, allowing more objective and automated quantitation of a variety of morphological and immunohistological parameters. Early reports indicate that medical vision systems are a reality and can provide for automated computer-generated histopathological diagnosis and quality assurance.
Humans↗