Biomedical subjects

J G Hennessey

Publications and source records attributed to J G Hennessey.

9 recordsLinked to original sources

PubMed1994

Digital video applications in radiologic education: theory, technique, and applications.

Computer-assisted instruction (CAI) has great potential in medical education. The recent explosion of multimedia platforms provides an environment for the seemless integration of text, images, and sound into a single program. This article discusses the role of digital video in the current educational environment as well as its future potential. An indepth review of the technical decisions of this new technology is also presented.

Computer-Assisted Instruction↗

PubMed1993

Development of a computer-assisted instructional tool for evaluation and treatment of renal masses. An experiment in hypermedia.

RATIONALE AND OBJECTIVES: Using a personal computer and a commercially available "authoring" application, the authors constructed an interactive hypermedia teaching tool for the evaluation and management of renal masses. METHODS AND RESULTS: Through a series of questions, images, illustrations, hypertext, and graphical flow charts, the user reviews the spectrum of renal masses, including neoplasms, inflammatory disease, cysts, and "pseudomasses." The various imaging modalities (computed tomography [CT], ultrasound [US], magnetic resonance imaging [MRI], and angiography) are illustrated, with selective advantages and disadvantages to each technique highlighted. Selected algorithms for evaluation and treatment of masses are provided. Text, questions, a teaching file, and algorithms form the major sections of the program. Numerous links within and between the major sections of the program, a capacity unique to hypermedia, allow for nonlinear entry into the program, tailored to the individual user. CONCLUSIONS: Preliminarily, medical students and residents have responded positively to this hypermedia project. Furthermore, their comments and criticism have provided important feedback for future updates and enhancements.

Computer-Assisted Instruction↗

PubMed1993

Detection of focal hepatic lesions with spiral CT: comparison of 4- and 8-mm interscan spacing.

OBJECTIVE: The objective of this study was to determine if spiral CT with 4-mm interscan spacing results in increased confidence in or rate of detection of focal hepatic lesions when compared with spiral CT with 8-mm interscan spacing. MATERIALS AND METHODS: Spiral CT scans of the liver of 42 consecutive patients with suspected hepatic disease were independently reviewed by three senior radiologists in two sets: one set was reconstructed with 8-mm interscan spacing and one set was reconstructed with 4-mm interscan spacing. The slice thickness was 8 mm for both data sets. The number and sizes of focal hepatic lesions were documented. RESULTS: Thirty-three of the 42 patients had least one focal lesion. The lesion size varied from 2 mm to 21 cm. When 8-mm interscan spacing was used, 297 lesions were detected (212 were considered definite). When 4-mm interscan spacing was used, 318 lesions were detected (258 were considered definite). Therefore, 7% more lesions were detected with 4-mm interscan spacing than with 8-mm interscan spacing (p = .05), and 22% more were diagnosed definitively (p < .01). If lesions larger than 4 cm are excluded, 10% more lesions were detected with 4-mm interscan spacing, and 33% more were diagnosed definitively. Of the lesions detected exclusively with 4-mm interscan spacing, 69% were less than 1.0 cm in diameter. CONCLUSION: Spiral CT with smaller interscan spacing (4 instead of 8 mm) results in increased confidence in and rate of detection of focal liver lesions. The additional benefit is most significant with smaller lesions.

Adult↗

PubMed1992

Computer-based radiological teaching programs: the challenge and trauma of development and implementation.

Computers are becoming an invaluable part of the radiologist's environment whether they are used as a source of the patient's clinical or laboratory information, to store x-ray or pathologic reports or as a viewing station for films. The use of computers in the educational environment is but a natural extension of the increased computerization of the radiologic department. This article reviews the use of personal computers in a teaching environment via the construction of the computed tomography teaching program entitled "CT: The Game." The decisions that must be made in terms of hardware and software prior to program development as well as the actual development are discussed. The potential of computers in terms of continuing education as well as in residency training programs is discussed with the potential for the future addressed.

Computer Systems↗

PubMed1991

The use of graphic design in an interactive computer teaching program.

The widespread diffusion of affordable computers into the scientific and educational community has provided the opportunity to design medical and scientific teaching programs illustrated either by hand or by utilizing commercially available software and manipulating existing computer generated images. The medical illustrator can provide the ideal aesthetic link between text format information and the visual representation of such knowledge in a concise presentation format. The availability of interactive multimedia programs has given the medical illustrator an environment to create and enhance Hypermedia designed specifically for the purpose of medical education. This paper will focus on the incorporation of illustration and screen design into "CT The Game," an experimental medical teaching program currently being developed in the Johns Hopkins Body CT Imaging Laboratory. The program is designed to provide an enjoyable approach to learning Computed Tomography (CT), and is directed toward an audience of medical students, residents, and fellows.

Computer Graphics↗

PubMed1991

Data base management in radiology: a simplified approach.

The increasing availability of personal and departmental computers in radiology departments has led to increasing interest in data management. Data base management software must be system compatible, simple, and flexible to insure its acceptance and constant use. Once in place, such a system streamlines the daily documentation of interesting cases for conference, follow-up, research, and quality assurance. The authors have developed such a data base program for tracking computed body tomography cases in their department, which can be run as a portable computer to maximize ease of access and therefore usage.

Database Management Systems↗

PubMed1990

Computer-based learning in radiology: a hypermedia application in CT.

Multimedia is a form of computer data presentation that uses multiple formats (text, illustration, sound, and animation) to enhance attention to and retention of presented information. Hypermedia is a nonlinear, branched access version of this that allows the user to pursue information more freely and variably than a linear format does. We used the hypermedia format to create an interactive medical teaching program that we believe holds the user's interest and attention better than a straight-text style does.

Computer-Assisted Instruction↗

PubMedDate not supplied

Edge complexity and partial volume effects.

PURPOSE: The accuracy of MR brain image segmentation is limited by so-called partial volume effects. We hypothesized that "edge complexity" (i.e., tissue class interface border complexity) significantly influences the magnitude of such effects. METHOD: To investigate partial volume effects and provide a vehicle for validation of segmentation algorithm accuracy in brain MRI. We developed a computer simulation, the "gigabrain." The simulation is based on interpolated (supersampled) data from actual MR studies. The voxels are assigned to one of five compartments (gray matter, white matter, CSF, fat, or "background"), the compartment interfaces are "jittered" to add high frequency "signal" or "edge complexity," and the voxels are populated with appropriate values determined from human data, low pass filtered (based on the MR scanner's point spread function), and subsampled back to the sampling and voxel size of the original MR data set. RESULTS: In comparison studies with actual phantoms and human MR data, our simulation approach was able to produce images whose appearance and quantitative values were comparable with the actual data, but only when edge complexity was added to the original MR data. CONCLUSION: Edge complexity is a significant source of partial volume effects. MR simulations must include edge complexity to adequately test segmentation algorithms.

Adipose Tissue↗

PubMedDate not supplied

Reliability and validity of an algorithm for fuzzy tissue segmentation of MRI.

PURPOSE: A new multistep, volumetric-based tissue segmentation algorithm that results in fuzzy (or probabilistic) voxel description is described. This algorithm is designed to accurately segment gray matter, white matter, and CSF and can be applied to both single channel high resolution and multispectral (multiecho) MR images. METHOD: The reliability and validity of this method are evaluated by assessing (a) the stability of the algorithm across time, rater, and pulse sequence; (b) the accuracy of the method when applied to both real and synthetic image datasets; and (c) differences in specific tissue volumes between individuals with a specific genetic condition (fragile X syndrome) and normal control subjects. RESULTS: The algorithm was found to have high reliability, accuracy, and validity. The finding of increased caudate gray matter volume associated with the fragile X syndrome is replicated in this sample. CONCLUSION: Since this segmentation approach incorporates "fuzzy" or probabilistic methods, it has the potential to more accurately address partial volume effects, anatomical variation within "pure" tissue compartments, and more subtle changes in tissue volumes as a result of disease and treatment. The method is a component of software that is available in the public domain and has been implemented on an inexpensive personal computer thus offering an attractive and promising method for determining the status and progression of both normal development and pathology of the CNS.

Adolescent↗