[Structured reporting of prostate cancer-self-development of a digital solution for prostate biopsies]. / Strukturierte Befundung am Beispiel des Prostatakarzinoms ­ Selbstentwicklung einer digitalen Lösung für Prostatastanzbiopsien.

BACKGROUND: The challenges in pathology and in structuring of data are increasing. Although considerable amounts of data are generated during the pathological diagnostic process, these data are often not available in a structured form and have to be extracted from the reports through a time-consuming and error-prone manual approach. However, the data are required for various internal and external purposes, such as for audits, tumor organ centers, reporting to cancer registries, different consortia, billing, various aspects within the organization, and for research. OBJECTIVES: The aim of the work was the development of a digital system for the direct and high-quality acquisition of structured pathology data using the example of biopsy-based diagnostics of prostate carcinoma. MATERIALS AND METHODS: A solution was created in cooperation with the pathology laboratory information system (LIS) provider imassense GmbH (Berlin, Germany), whose LIS 'Informationssystem der digitalen Pathologie' (IS-P) is used at the Institute of Pathology at the University Hospital Essen. RESULTS AND CONCLUSION: Over a period of about 1.5 years, a system that is capable of structured reporting according to local, national (S3 guidelines, German Cancer Society) and international (International Collaboration on Cancer Reporting [ICCR]) specifications was developed and subsequently used. The data are stored in readable databases and can easily be generated via IS­P. Apart from the disadvantage of a highly specialized solution adapted to the LIS, the project also shows the feasibility in the local academic environment with the above-mentioned advantages.

Virtual dermatohistopathology at http://www.pathowiki.org.

PATHOWIKI (http://www.pathowiki.org) is a new specialized information system in the form of a web-based wiki with content from all sub-disciplines of human pathology. Essential components are articles and specimens which are located thematically in dermatopathology. The project is presented on the basis of impressive examples and possibilities. The ability to link all kinds of content and integrate pattern analysis theories creates an effective tool for teaching and training in dermatopathology. Collaborative work ensures the effective usage of available resources and a continually growing amount of content, the quality of which depends on the number of users and should be as high as possible. Therefore, all interested colleagues are invited to support the project.

Lossless compression of JPEG2000 whole slide images is not required for diagnostic virtual microscopy.

The use of lossy compression in medical imaging is controversial, although it is inevitable to reduce large data amounts. In contrast with lossy compression, lossless compression does not impair image quality. In addition to our previous studies, we evaluated virtual 3-dimensional microscopy using JPEG2000 whole slide images of gastric biopsy specimens with or without Helicobacter pylori gastritis using lossless compression (1:1) or lossy compression with different compression levels: 5:1, 10:1, and 20:1. The virtual slides were diagnosed in a blinded manner by 3 pathologists using the updated Sydney classification. The results showed no significant differences in the diagnosis of H pylori between the different levels of compression in virtual microscopy. We assume that lossless compression is not required for diagnostic virtual microscopy. The limits of lossy compression in virtual microscopy without a loss of diagnostic quality still need to be determined. Analogous to the processes in radiology, recommendations for the use of lossy compression in diagnostic virtual microscopy have to be worked out by pathology societies.

Improvements in education in pathology: virtual 3D specimens.

Virtual three-dimensional (3D) specimens correspond to 3D visualizations of real pathological specimens on a computer display. We describe a simple method for the digitalization of such specimens from high-quality digital images. The images were taken during a whole rotation of a specimen, and merged together into a JPEG2000 multi-document file. The files were made available in the internet (http://patho.med.uni-magdeburg.de/research.shtml) and obtained very positive ratings by medical students. Virtual 3D specimens expand the application of digital techniques in pathology, and will contribute significantly to the successful introduction of knowledge databases and electronic learning platforms.

Lossy compression in diagnostic virtual 3-dimensional microscopy--where is the limit?

Data compression is inevitable to reduce the huge data amounts of virtual slides, especially in virtual 3-dimensional (3D) microscopy. Lossy compression influences the image quality and leads to recognizable compression artifacts above a compression ratio of 20:1 in JPEG2000 format. To test out whether higher compression ratios are acceptable in diagnostic pathology, we prepared virtual 3D slides of gastric biopsy specimens with or without Helicobacter pylori gastritis using 5 different compression ratios as follows: 20:1, 40:1, 50:1, 75:1, and 200:1. The virtual 3D slides were diagnosed in a blinded manner by 3 pathologists according to the updated Sydney classification. The results showed no significant differences using virtual 3D slides with any compression of up to 200:1. We conclude that compression ratios higher than those commonly used can be applied in virtual microscopy, even in diagnostic applications.

Virtual 3D microscopy using multiplane whole slide images in diagnostic pathology.

To reproduce focusing in virtual microscopy, it is necessary to construct 3-dimensional (3D) virtual slides composed of whole slide images with different focuses. As focusing is frequently used for the assessment of Helicobacter pylori colonization in diagnostic pathology, we prepared virtual 3D slides with up to 9 focus planes from 144 gastric biopsy specimens with or without H pylori gastritis. The biopsy specimens were diagnosed in a blinded manner by 3 pathologists according to the updated Sydney classification using conventional microscopy, virtual microscopy with a single focus plane, and virtual 3D microscopy with 5 and 9 focus planes enabling virtual focusing. Regarding the classification of H pylori, we found a positive correlation between the number of focus planes used in virtual microscopy and the number of correct diagnoses as determined by conventional microscopy. Concerning H pylori positivity, the specificity and sensitivity of virtual 3D microscopy using virtual slides with 9 focus planes achieved a minimum of 0.95 each, which was approximately the same as in conventional microscopy. We consider virtual 3D microscopy appropriate for primary diagnosis of H pylori gastritis and equivalent to conventional microscopy.

Digital workflow management for quality assessment in pathology.

Information systems (IS) are well established in the multitude of departments and practices of pathology. Apart from being a collection of doctor's reports, IS can be used to organize and evaluate workflow processes. We report on such a digital workflow management using IS at the Department of Pathology, University Hospital Magdeburg, Germany, and present an evaluation of workflow data collected over a whole year. This allows us to measure workflow processes and to distinguish the effects of alterations in the workflow for quality assessment. Moreover, digital workflow management provides the basis for the integration of diagnostic virtual microscopy.

Digital pathology: DICOM-conform draft, testbed, and first results.

Hospital information systems are state of the art nowadays. Therefore, Digital Pathology, also labelled as Virtual Microscopy, has gained increased attention. Triggered by radiology, standardized information models and workflows were world-wide defined based on DICOM. However, DICOM-conform integration of Digital Pathology into existing clinical information systems imposes new problems requiring specific solutions concerning the huge amount of data as well as the special structure of the data to be managed, transferred, and stored. We implemented a testbed to realize and evaluate the workflow of digitized slides from acquisition to archiving. The experiences led to the draft of a DICOM-conform information model that accounted for extensions, definitions, and technical requirements necessary to integrate digital pathology in a hospital-wide DICOM environment. Slides were digitized, compressed, and could be viewed remotely. Real-time transfer of the huge amount of data was optimized using streaming techniques. Compared to a recent discussion in the DICOM Working Group for Digital Pathology (WG26) our experiences led to a preference of a JPEG2000/JPIP-based streaming of the whole slide image. The results showed that digital pathology is feasible but strong efforts by users and vendors are still necessary to integrate Digital Pathology into existing information systems.

A composite bone graft substitute for anterior cervical fusion: assessment of osseointegration by quantitative computed tomography.

STUDY DESIGN: An ongoing prospective nonrandomized trial was conducted with 146 patients who underwent anterior cervical fusion with a bone graft substitute. The results for 78 patients followed up a minimum of 2 years are reported by an independent observer. OBJECTIVE: To investigate the clinical efficacy and osseointegration of the implant. SUMMARY OF BACKGROUND DATA: Most of the cervical cages provide an immediate load-bearing capacity, but not necessarily a solid fusion. The bony ingrowth can hardly be evaluated by flexion-extension plain radiographs, especially if a part of the implant is made of titanium. METHODS: The composite bone graft substitute consists of a rectangular fenestrated titanium cage filled with a highly porous hydroxyapatite cylinder soaked with bone marrow aspirated from a vertebra. Altogether, 102 implants were inserted for anterior cervical fusion. The bone ingrowth was measured in 50 patients by quantitative computed tomography of the implant and the adjacent vertebrae after 1 week, then 6 and 12 months after surgery. The investigation was repeated in 24 randomly selected patients 24 months after surgery. RESULTS: The surgery benefited 42 of 48 patients with myelopathy, 27 of 28 patients with radiculopathy, and both patients with anterior horn cell syndrome. No graft substitute-related complications were observed, and no revision surgery was performed. Six months after surgery, quantitative computed tomography showed up to a 14% increase in the hydroxyapatite mass in the core of the implant, which was statistically significant (P < 0.001). At 1 year, the newly formed hydroxyapatite mass increased to 23%, and in 2 years reached 24%. CONCLUSIONS: The composite implant is effective as a bone graft substitute, providing immediate load-bearing capacity, an osteoconductive scaffold, and osteoinductive potency. After surgery, the increase in hydroxyapatite radiodensity was apparent in plain computed tomography scans and confirmed to be significant by quantitative computed tomography.