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Biomedical subjects

N J Mankovich

Publications and source records attributed to N J Mankovich.

At least 19 recordsLinked to original sources
PubMed1998

Security for the digital information age of medicine: issues, applications, and implementation.

Privacy and integrity of medical records is expected by patients. This privacy and integrity is often mandated by regulations. Traditionally, the security of medical records has been based on physical lock and key. As the storage of patient record information shifts from paper to digital, new security concerns arise. Digital cryptographic methods provide solutions to many of these new concerns. In this article we give an overview of new security concerns, new legislation mandating secure medical records and solutions providing security.

Computer Security↗
PubMed1998

PACS/information systems interoperability using Enterprise Communication Framework.

Interoperability among healthcare applications goes beyond connectivity to allow components to exchange structured information and work together in a predictable, coordinated fashion. To facilitate building an interoperability infrastructure, an Enterprise Communication Framework (ECF) was developed by the members of the Andover Working Group for Healthcare Interoperability (AWG-OHI). The ECF consists of four models: 1) Use Case Model, 2) Domain Information Model (DIM), 3) Interaction Model, and 4) Message Model. To realize this framework, a software component called the Enterprise Communicator (EC) is used. In this paper, we will demonstrate the use of the framework in interoperating a picture archiving and communication system (PACS) with a radiology information system (RIS).

Computer Communication Networks↗
PubMed1997

Security for the digital information age of medicine: issues, applications, and implementation.

Privacy and integrity of medical records is expected by patients. This privacy and integrity is often mandated by regulations. Traditionally, the security of medical records has been based on physical lock and key. As the storage of patient record information shifts from paper to digital, we find new security concerns. Digital cryptographic methods provide solutions to many of these new concerns. In this paper we discuss the new security concerns, new legislation mandating secure medical records, and solutions providing this security.

Computer Security↗
PubMed1997

Method for segmenting chest CT image data using an anatomical model: preliminary results.

We present an automated, knowledge-based method for segmenting chest computed tomography (CT) datasets. Anatomical knowledge including expected volume, shape, relative position, and X-ray attenuation of organs provides feature constraints that guide the segmentation process. Knowledge is represented at a high level using an explicit anatomical model. The model is stored in a frame-based semantic network and anatomical variability is incorporated using fuzzy sets. A blackboard architecture permits the data representation and processing algorithms in the model domain to be independent of those in the image domain. Knowledge-constrained segmentation routines extract contiguous three-dimensional (3-D) sets of voxels, and their feature-space representations are posted on the blackboard. An inference engine uses fuzzy logic to match image to model objects based on the feature constraints. Strict separation of model and image domains allows for systematic extension of the knowledge base. In preliminary experiments, the method has been applied to a small number of thoracic CT datasets. Based on subjective visual assessment by experienced thoracic radiologists, basic anatomic structures such as the lungs, central tracheobronchial tree, chest wall, and mediastinum were successfully segmented. To demonstrate the extensibility of the system, knowledge was added to represent the more complex anatomy of lung lesions in contact with vessels or the chest wall. Visual inspection of these segmented lesions was also favorable. These preliminary results suggest that use of expert knowledge provides an increased level of automation compared with low-level segmentation techniques. Moreover, the knowledge-based approach may better discriminate between structures of similar attenuation and anatomic contiguity. Further validation is required.

Computer Simulation↗
PubMed1995

Structured knowledge representation: an improved methodology for communication of hospital policy.

The optimal operational integrity of a health care facility depends upon the correct interpretation of an adherence to well designed and written policies. Memos describing policy and procedures can be ambiguous, hindering their comprehension rather than helping it. Two alternative methods have been developed for communicating policy: the algorithmic flow chart and a computer decision support program. To determine the best means of communicating policy, the written memo, flow chart, and computer program were compared in scenario presentation interviews. The average time required to complete the test scenarios was five minutes for the traditional memo, two minutes for the algorithm, and two minutes for the computer program. Accuracy improves markedly from the traditional memo to the computer program. ANOVA reveals that the flow chart and computer program are significantly superior to memos as methods for communicating hospital policy.

Algorithms↗
PubMed1994

Absence of radiometric differentiation between periapical cysts and granulomas.

A recent study reported that the mean density of periapical cysts was greater than that of periapical granulomas. This study, which used a larger sample size and a robust method for standardization of density and contrast between images, found no difference between the radiographic density of cysts and granulomas classified by microscopic evaluation. Cysts tend to be larger than granulomas, but there was wide variation in size of both types of lesions. There was no significant correlation between the density of a lesion and its size.

Absorptiometry, Photon↗
PubMed1994

Surgical planning using three-dimensional imaging and computer modeling.

The acquisition, processing, and use of three-dimensional (3D) imaging provide new insights into normal and abnormal craniofacial anatomy. In this article, characteristics of CT and MRI scanning are reviewed along with the methods used to delineate tissues and produce 3D patient displays, including contouring, shaded surface, and volumetric processing. The use of 3D model fabrication for surgical planning is discussed with examples of the production of a custom CT-based auricle model and the use of rapid prototyping technology to create models for custom alloplastic implant surgery. The review concludes with some speculation about the future of 3D medical imaging as it will influence surgical training and practice over the coming decades.

Diagnostic Imaging↗
PubMed1994

Stereolithographic model construction from CT for assessment and surgical planning in congenital aural atresia.

Surgical planning for the treatment of congenital aural atresia has depended greatly on the use of high resolution computerized tomography (CT) and, recently, three-dimensional CT for visual representation of the complex anatomy associated with this condition. Computerized plastic model construction, stereolithography, allows the digital data obtained through CT scanning to produce a life-size anatomically accurate plastic model of the structure scanned. When this technique is applied to congenital aural atresia there is good bony surface rendering as well as complete representation of the deeper structures contained within the temporal bone, including the middle ear cleft, ossicular mass, and fallopian canal. The surgeon can use this model to augment imaging in becoming familiar with the patient's unique anatomy and to practice a planned surgical procedure.

Adolescent↗
PubMed1993

Teleconferencing for cost-effective sharing of radiology educational resources: potential and technical development.

To develop a cost-effective method of sharing educational resources, a dial-up teleconferencing network was implemented between three radiologic sites for a 30-day period of evaluation. By means of standard dial-up telephone channels, compressed video and audio signals displayed radiologic images, slides, and text, allowing residents and faculty from the three sites to participate in sight and sound interactions. Each of the three sites used compressed video/audio coder-decoders (codecs) conforming to the Consultative Committee on International Telegraphy and Telephony H.261 standard. Four video cameras were used at each site, and the audio was run in full duplex mode. A multipoint video bridge was used to broadcast codec output signals to the input lines of the other codecs. Our evaluation found audio quality to be suboptimal, but capable of being improved; diagnostic image quality was adequate when a video zoom mode was used; the digital-archive mode of the codec proved advantageous; the H.261 codec permitted participation from all sites; and all conference lecturers were able to conduct their conferences as they were accustomed. Although audio quality and spatial resolution need to be improved, the results of this pilot study imply that dial-up compressed video conferencing has the potential to become a practical, cost-effective method of sharing educational resources by means of interactive radiologic multisite educational programs.

Computer Communication Networks↗
PubMed1992

Stereolithographic models for surgical planning: preliminary report.

Recent application of computer graphics, using standardized cephalometric analyses, have allowed the surgeon to visualize the predicted surgical outcome on the computer video monitor. Stereolithographic models constructed from digital image data (computed tomography and magnetic resonance) will allow the surgeon to view the external and internal anatomy prior to surgery. This article describes the development of such technology and reports its use in one case.

Adult↗
PubMed1992

Three-dimensional CT scan reconstruction for the assessment of congenital aural atresia.

Major advances in medical computer graphics workstations have provided the capability to produce high quality three-dimensional image reconstructions from conventional thin-section computerized tomography (CT) scans with the ability to observe the imaged structure from any angle, with views and dimensions that are comparable to actual dissections. We have applied this technique to the temporal bone to assess congenital aural atresia in surgical planning for hearing reconstruction in six patients. The digital information produced by thin-section CT scanning allowed for the re-creation of multiplanar reformatted, shaded surface, and volumetric images. With this technique the surface landmarks of the temporal bone were readily visualized, the configuration of the atretic plate and middle ear in relation to the tegmen and glenoid fossa could be precisely assessed and the structure of the ossicular mass was easily analyzed. Most significantly, the facial nerve could be accurately and easily envisioned in its entire intratemporal course. Three-dimensional imaging is a highly desirable means for observing CT scan data to facilitate the surgical planning for correction of congenital aural atresia.

Adolescent↗
PubMed1991

Exposure rates in high-level-control fluoroscopy for image enhancement.

High-level fluoroscopic boost options that exceed conventional exposure limits are available as a means of reducing quantum mottle during angiography. Federal law does not specify exposure limits for such high-level controls but requires specific means of activation to safeguard against inadvertent use. The American Association of Physicists in Medicine recently recommended that high-level exposure rates not exceed 2.58 mC/kg/min (10R/min). At six institution surveyed, maximum exposure rates ranged from 5.42 to 24 mC/kg/min (21-93 R/min). Activation of high-level capability varied from a simple foot switch to a keyed interlock requiring a second operator to engage. There appears to be no industry coherence in high-level control exposure limits as yet, although the Center for Devices and Radiological Health recently initiated an investigatory program.

Environmental Exposure↗
PubMed1991

NMINT--introductory courseware for nuclear medicine: database design.

Computer-Aided Instruction (CAI) provides a dynamic and self-paced learning experience to the medical trainee. Microcomputer based hypermedia systems integrate text, graphics, and image information. We present the design of an introductory CAI course for nuclear medicine called NMINT and elaborate on the underlying relational database that contains clinically relevant information and links to local or remote image storage over high speed networks. The IBM PS/2 Windows system uses Toolbook software augmented by C language modules for image and image-overlay database access. The current implementation stores text, graphical lesson material, and image index information on microcomputer magnetic disk; image data are stored on the attached optical disk. The storage architecture is described in detail. We emphasize its multi-access methods and its expandability into department-wide image networks.

Computer Graphics↗
PubMed1990

The display of three-dimensional anatomy with stereolithographic models.

Stereolithography, a new technique of prototype fabrication developed for the aerospace industry, offers a unique way to display patient anatomy. Like current computer aided design (CAD) systems, it uses digital image data from computed tomography (CT) and magnetic resonance (MR) to produce a physical model. Unlike conventional CAD it does not require a cutting tool and, therefore, CAD toolpath limitations do not exist. The stereolithography apparatus uses an ultraviolet laser to selectively polymerize and solidify a polymeric liquid plastic solution under computer control. The device was used to produce a model of cranial bony anatomy from CT image data, providing full internal detail in the constructed model, including encased sinuses, foramen, and potentially complete internal anatomy within a closed skull. The advantages and disadvantages of this technology are reviewed with an emphasis on future development.

Computer Graphics↗
PubMed1990

Three-dimensional image display in medicine.

This article is a tutorial on the methods used to create three-dimensional (3-D) images for use in displaying patient anatomy. This new view into anatomy has developed over the last 10 years from the need of surgeons, radiation therapists, and radiologists to integrate the many images resulting from the recent growth in tomographic imaging including computed tomography (CT) and magnetic resonance imaging (MRI). CT and MRI studies result in 30 to 100 images. 3-D imaging processes and integrates this image data volume and extracts more meaningful, derivative images via multiplanar reconstruction (MPR), shaded surface processing, or volumetric processing. MPR reslices the image volume to produce novel views of patient anatomy while retaining the image voxel intensities. Realistic shaded surface display of 3-D objects can involve extensive processing of the images to create computer representations of objects rendered into a displayable 3-D scene. Volumetric imaging combines the voxel processing of MPR with the techniques of tissue classification and surface shading to produce novel projections of the image data volume that allow automated creation of 3-D scenes without recourse to the complexities of object delineation. As the ultimate 3-D display, recent advances in computer-aided design (CAD) and computer-aided manufacturing (CAM) allow the fabrication of physical models of anatomy using computer-controlled milling machines. New technology that actually builds the model layer by layer from a liquid plastic offers the possibility of complete models with intact internal anatomy. The growth in 3-D is certain as hardware and software costs decrease and medical professionals find further applications for this technology.

Humans↗
PubMed1988

Local area networks for radiology.

This article is a tutorial on local area networks (LAN) for radiology applications. LANs are being implemented in radiology departments for the management of text and images, replacing the inflexible point-to-point wiring between two devices (computer-to-terminal). These networks enable the sharing of computers and computer devices, reduce equipment costs, and provide improved reliability. Any LAN must include items from the following four categories: transmission medium, topology, data transmission mode, and access protocol. Media for local area networks are twisted pair, coaxial, and optical fiber cables. The topology of these networks include the star, ring, bus, tree, and circuit-switching. Data transmission modes are either analog signals or digital signals. Access protocol methods include the broadcast bus system and the ring system. A performance measurement for a LAN is the throughput rate as a function of the number of active computer nodes. Standards for LANs help to ensure that products purchased from multiple manufacturers will operate successfully.

Humans↗