Porous-coated anatomic total hip prostheses: radiographic analysis and clinical correlation.

The radiographic changes of 46 bone-ingrowth, porous-coated anatomic total hip prostheses were reviewed and compared to the clinical outcome. The average postoperative follow-up was 32 months. The radiographic features that were assessed included subsidence; periprosthetic lucencies; periosteal, endosteal, and heterotopic new bone; loose beads; implant position; and tightness of fit. Clinical results were based on the Harris hip score. All acetabular components fared well. Three of the femoral stem components needed revision. The radiographic finding that correlated best with outcome was subsidence of more than 10 mm, especially if it continued to increase more than 1 year after surgery. Other findings related to failure were loosely placed femoral stems and the presence of loose beads. However, subsidence was such a powerful predictor of clinical outcome, and the other features were so weak, that combinations of variables did not improve the assessment of outcome. Close attention should be paid to subsidence in follow-up studies.

Radiology systems of the nineties: meeting the challenge of change.

Digital imaging technology, particularly reconstructed images such as computed tomography and magnetic resonance imaging, has fueled the increased demand for radiologic services but has intensified storage and communications problems. Today more than 25% of radiologic examinations are digital in origin and, with progressive replacing of film images by digital images likely through the introduction of imaging plate technology, the radiology profession is undertaking the massive effort of evolving a new system where digital images will be transmitted, stored, retrieved and displayed by a multicomponent system connected by a local area network. Through this system, images will be nearly instantly accessible to anyone who needs them. A leading hypothesis is that when the volume of digital examinations reaches 50% of the whole, cost and efficiency considerations will lead to a massive conversion to the digital image management system, which will progress spontaneously. This conversion, unless planned for in today's equipment acquisitions, could lead to great economic stress in hospitals. The 50% point may be reached by the early 1990s.

ACR-NEMA digital imaging and communications standards: minimum requirements.

The purposes, implications, and history of development of the American College of Radiology-National Electrical Manufacturers Association (ACR-NEMA) Digital Imaging and Communication Standard and its contents are briefly described, and the minimum requirements of the ACR-NEMA Digital Imaging and Communication Standard are described with a concise introduction of each layer. The usefulness, validity, current status, and future development of the standard are also discussed.

Radiology systems of the 1990s--meeting the challenge of change.

Digital imaging technology, particularly reconstructed images such as computed tomography and magnetic resonance imaging, has fueled the increased demand for radiologic services but has intensified storage and communications problems. Today more than 25% of radiologic examinations are digital in origin and, with progressive replacing of film images by digital images likely through the introduction of imaging plate technology, the radiology profession is undertaking the massive effort of evolving a new system where digital images will be transmitted, stored, retrieved and displayed by a multicomponent system connected by a local area network. Through this system, images will be nearly instantly accessible to anyone who needs them.A leading hypothesis is that when the volume of digital examinations reaches 50% of the whole, cost and efficiency considerations will lead to a massive conversion to the digital image management system, which will progress spontaneously. This conversion, unless planned for in today's equipment acquisitions, could lead to great economic stress in hospitals. The 50% point may be reached by the early 1990s.

The digital computer in medical imaging: a critical review.

The present use of computers in radiology is reviewed. The major functions of a fully digital radiology department are described as (a) control and management, (b) image acquisition, (c) image distribution, (d) image interpretation, (e) image redisplay, and (f) image archiving. In addition, the benefits of a fully digital department and the problems that must be solved before it can be achieved are discussed.

The radiologist's role in the management of chondrosarcoma.

The decision whether to call a slowly growing chondrosarcoma of a long bone benign or malignant is difficult for the pathologist, who must consider the location of the biopsy sample as well as the microscopic findings. The radiologist examining the mineralization of the lesion may also have a difficult time arriving at a prognosis. The author suggests that calcific rings within a cartilaginous tumor may be a sign of a low-grade lesion. On observing such a finding, it is necessary to determine whether or not the lesion is invading the surrounding bone or cartilage. If the lesion is unmistakably malignant, or even if there is any question, it must be excised in its entirety, as curettage is not sufficient to halt the spread of tumor. In most cases the radiologist will have a better chance of assessing possible malignancy than the pathologist, particularly if distinction between benign and low-grade malignant tumor is involved.

Estimating rate of growth in bone lesions: observer performance and error.

In an experimental study of reader experience in identifying the variables essential to grading bone neoplasms, reader error is measured against book grade, a human consensus of the presence or absence of key variables. The average accuracy for classifying focal lesions into slow or fast categories is 83.4% for 890 readings as compared with average diagnostic accuracy of 53.7%. Analyses of human error have provided insight into how to improve the grading algorithm without significant loss of its ability to separate lesions into meaningful categories.

Determining growth rates of focal lesions of bone from radiographs.

Rate of growth divides focal lesions of bone into two classes which are largely mutually exclusive. Not all focal lesions require biopsy, and grading is especially helpful in deciding which should be biopsied and which may be safely followed. The statistical proof and logic of grading as an expression of growth rate are presented with a set of rules establishing each of the five grades in the presence of bone destruction. The radiologic signs necessary to establish rates are described and illustrated.

Towards computer analysis of pulmonary infiltration.

A feasibility study is described to provide quantitative texture measures to distinguish between normal lung, alveolar infiltrates and interstitial infiltrates. Advanced computer imaging technology and decision making processes were applied to distinguish between these textural patterns. The results, based on computer extracted quantitative measures, show an excellent separation of the three classes considered with 95% accuracy in the training phase and 90% accuracy in the testing phase.

General purpose digital display system for computed tomography images.

The authors describe a microprocessor-based digital image display system utilizing a solid-state image memory with a high quality television-type monitor for display of computed tomography images. It is an alternative to a commercially available display system, and offers the potential for research in digital image display. It is now under clinical evaluation. Image input to the stand-alone display system is via 9-track magnetic tape common to almost all CT machines, and it may be programmed to accept digital tapes from any type of CT machine and display them in a common format.

Missouri Automated Radiology System: a dynamic, interactive diagnostic and management system for radiant images.

Missouri Automated Radiology System has functioned in full support of the Department of Radiology for more than 7 years. For the past 5 years, MARS has functioned as a minicomputer system on a DEC (Digital Equipment Corporation) PDP-15 computer. While continuing to effectively support the department, in daily use by 20 staff and 15 resident physicians, MARS has continued to function in a research and development mode. With the continuous development of new applications, MARS is now essential to the function of the department and has again proven the point that physicians and computers can function symbiotically in the medical environment.