Trauma of the facial bones and skull

Facial trauma is frequent and mainly caused by motor vehicle accidents. Due to this main etiologic factor, trauma to the facial skeleton is often associated with serious injuries, commonly involving the brain, chest or abdomen. As a consequence, the initial clinical management of these patients includes control of hemorrhage and immediate assessment of life-threatening injuries, including the maintenance of the airways. Patients presenting with facial trauma are initially evaluated with a systematic clinical examination because many fractures can be accurately diagnosed by inspection and palpation alone. In these cases plain film radiographs serve only for confirmation and documentation of the diagnosis. In many other cases accompanying and extensive soft tissue swelling may clinically obscure fractures. A complete and accurate evaluation of these patients requires additional radiological imaging methods. A series of plain films may be generally sufficient but in most of the cases they can be regarded as initial screening methods for more thorough diagnosis with computed tomography (CT). In trauma patients CT is the imaging method of choice because it shows more fracture lines and displaced fragments than any other imaging modality. CT delineates soft tissue and bony structures and can localize and even characterize foreign bodies. A complete and accurate characterization of the fracture type and potentially associated complications in mandatory for the appropriate treatment and can only be achieved by careful radiological (CT) evaluation.     

Trends of twinning rates in ten countries, 1972-1996

The data quality and completeness of acquired images, which we refer to as integrity, is considered as the most important requirement in the image acquisition design of the Picture Archiving and Communication System (PACS). The Digital Imaging and Communications in Medicine (DICOM) standard significantly simplifies the task of acquiring radiological images from a DICOM compliant imaging system into the PACS. However, human interaction with the imaging system by changing the DICOM communication settings can result in missing images during the PACS image acquisition. A scheme based on the DICOM Query and Retrieve (Q/R) service class was developed to automatically identify and recover missing images. In addition, grouping sequential scanned images such as a CT and MR image series is another potential process that can miss images because of no indication of the end of series. Two methods are presented for determining the end of series and the pros and cons of each method are discussed in detail. Two experiments in a real clinical environment were conducted; one with and one without the Q/R implementation. The statistical results indicate two highlights from this work. First, the Q/R scheme faithfully recovered all missing images caused by human interaction with the DICOM compliant imaging system. Second, there was no single image slice missed when grouping slices into a series using the presented grouping algorithm in the two experimental periods.     

European standardization efforts: an important framework for medical imaging

For several years now, users have been waiting for standards allowing medical images to be exchanged, managed, stored and manipulated. Standards are prerequisites for the development of PACS and IMACS systems. It is because of the lack of standards that PACS have not yet widely been implemented. The ACR-NEMA committee (American College of Radiology--National Electronical Manufactures Association) are developing an image communication standard: DICOM 3.0. This should allow interconnection of different imaging modalities and other PACS nodes. Part of the DICOM 3.0 work will be demonstrated at RSNA 93 with involvement of Europe. In the European Standardization Committee (CEN), the technical committee responsible for the standardization activities in Medical Informatics (CEN TC 251), has agreed upon the directions and the scopes to be followed in this field. They are described in the directory of the European standardization requirements for health care informatics and programme for the development of standard adopted on 28 February 1991 by CEN TC 251. Top-down objectives describe the common framework and items like terminology, security, while the more bottom-up oriented items describe fields like medical imaging and multi-media. Since CEN TC 251 started working, an important coordination took place between Europe and the US and Japan, resulting in a common future approach. CEN TC 251 is setting the scene for a more technologically independent standard on a mid term basis. This standard will first have to be proto-typed before it can be published, because it must be possible to implement the standard, too much complexity will not be accepted by the industry. The European imaging standardization work based on the ISO/IPI standard, will be briefly explained; as well as the general framework model and object oriented model; the interworking aspects, and the relation to ISO standards. One should realize be realised that a standard is needed, which is not too ambitious. Because DICOM 3.0 will be ready soon, Europe has decided to support these activities and will concentrate on the next step to be taken.     

The SNOMED DICOM microglossary: controlled terminology resource for data interchange in biomedical imaging

This paper describes an authoritative, non-proprietary information resource that provides an efficient mechanism for embedding specialized clinical knowledge into the design of healthcare telecommunications systems. The resource marries two types of data interchange standards, a message/electronic-document standard and a terminology standard. In technical terms, it is part protocol and part database. Industry, academia, professional specialty societies, and the federal government participated in its development. The development of multi-specialty content has broadly engaged biomedical domain experts to an unprecedented degree in voluntary, non-proprietary message/document-standards development. The resource is the SNOMED DICOM Microglossary (SDM), a message-terminology (or document-content) mapping resource. The message/electronic-document standard is DICOM (Digital Imaging and Communications in Medicine). The terminology standard is SNOMED, (Systematized Nomenclature of Human and Veterinary Medicine). The SDM specifies the mapping of multi-specialty imaging terminology from SNOMED to DICOM data elements. DICOM provides semantic constraints and a framework for discourse that are lacking in SNOMED. Thus the message standard and the computer-based terminology both depend upon and complete each other. The combination is synergistic. By substitution of different templates of specialty terminology from the SDM, a generic message template, such as the DICOM Visible Light (Color Diagnostic) Image or the DICOM Structured Reporting specification can be reconfigured for diverse applications. Professional societies, with technical assistance from the College of American Pathologists, contribute and maintain their portions of the terminology, and can use SDM templates and term lists in clinical practice guidelines for the structure and content of computer-based patient records.     

An evaluation of the signal and noise characteristics of four CCD-based film digitizers

Film digitizers are common devices in radiology departments involved with picture archive and communication systems (PACS) and teleradiology. In this paper, we studied the performance of film digitizers based on charge-coupled device detectors (CCD digitizers), and compared this with the performance of a laser digitizer (the de facto standard). Our focus was on the assessment of signal, noise and useful optical density range performance. A function (L* delta D) derived from the Rose model was used to evaluate these parameters in absolute terms, based their predicted ability to detect objects of specific size and optical density difference with respect to background. We studied CCD digitizers from four different vendors and found that none was able to reliably operate up to the maximum density of 3.0 required to digitize plain radiographs, while the laser digitizer was capable of this task. Our analysis also indicated that two of the four CCD digitizers were adequate for digitizing laser-printed cross-sectional images in certain cases. Finally, our analysis indicated that digitization of SMPTE pattern films along with visual assessment of the 5% and 95% contrast patches was not sufficient for determining the utility of film digitizers for clinical tasks. Computation of the L* delta D function provides a useful means of assessing the performance of film digitizers (e.g., for acceptance testing and quality control), and this technique may be adaptable for evaluation of other digital imaging modalities.     

Integration of occupational health and safety, environmental and quality management system standards

Occupational health and safety, environmental, and quality (SEQ) issues are commonly managed by three separate departments within organizations. Because of a number of commonalities in the three management systems, there could be a degree of overlap that might lead to inefficiencies. By integrating these three management systems into one SEQ system, the duplication of effort could be minimized and the health and safety, environmental, and quality issues could be managed by one common proactive approach. The draft Australian standard for an occupational health and safety (OHS) management system and the internationally accepted standards for environmental (ISO 14001) and quality (ISO 9001) management systems were analyzed to identify all requirements of the three management systems and integrate this into one SEQ management system standard.     

Rapid detection of traumatic effusion using surgeon-performed ultrasonography

BACKGROUND: In the injured patient, rapid assessment of the thorax can yield critical information for patient management and triage. OBJECTIVES: The objectives of this prospective study were (1) to determine if experienced surgeon sonographers could successfully use a focused thoracic ultrasonographic examination to detect traumatic effusion, and (2) to compare the accuracy and efficiency of ultrasonography with supine portable chest radiography. METHODS: Surgeon-sonographers performed thoracic ultrasonographic examinations on patients with blunt and penetrating torso injuries during the Advanced Trauma Life Support secondary survey. All patients also underwent portable chest radiography. Performance times for ultrasonography and chest radiography were recorded. Comparisons were made of the performance times and accuracy of both tests in detecting traumatic effusion. RESULTS: In 360 patients, there were 40 effusions, 39 of which were detected by ultrasonography and 37 of which were detected by chest radiography. The 97.5% sensitivity and 99.7% specificity observed for thoracic ultrasonography were similar to the 92.5% sensitivity and 99.7% specificity for portable chest radiography. Performance time for ultrasonography was significantly faster than that for chest radiography (1.30 +/- 0.08 vs. 14.18 +/- 0.91 minutes, p < 0.0001). CONCLUSION: Surgeons can accurately perform and interpret a focused thoracic ultrasonographic examination to detect traumatic effusion. Surgeon-performed thoracic ultrasonography is as accurate but is significantly faster than supine portable chest radiography for the detection of traumatic effusion.     

Benign fibrous mesothelioma successfully treated by thoracoscope-assisted surgery: report of a case

We report herein the case of an 84-year-old man in whom a benign fibrous mesothelioma (BFM) was successfully treated by thoracoscope-assisted surgery. In September 1996, the patient underwent a sigmoidectomy for colon cancer, soon after which a followup examination disclosed a coin lesion on his chest X-ray film. The patient was readmitted to our hospital in November 1996 for further investigation of this tumor. A chest computed tomography scan revealed a 3.5 x 3.0 cm homogeneous tumor arising from the pleura. A needle biopsy was performed under ultrasonographic guidance, and the specimen was histopathologically diagnosed as a BFM. In view of his poor respiratory function, the tumor was excised by thoracoscope-assisted surgery. This case report serves to demonstrate the benefits of thoracoscope-assisted surgery for such patients.     

The role of CT and MR in imaging the complications of sickle cell disease

Sickle cell disease is the most common inherited haemoglobinopathy described. Complications of sickle cell disease (SCD) are due to chronic haemolysis of fragile red cells or secondary to vascular occlusion by sickled red cells with subsequent tissue infarction. Traditionally plain film radiography has been the mainstay in the assessment of patients with SCD, but increasingly magnetic resonance (MR) imaging and computed tomography (CT) are being used. In this review the imaging features of a range of complications of SCD are demonstrated with particular emphasis on CT and MR.     

Modelling of radiological services in the context of a hospital information system: does the DICOM standard meet the requirements?

PROBLEM: The data model given in the DICOM standard is examined under the aspect of system integration. Semantic properties of the IODs (information object definitions) and their relationships are investigated. METHOD: Starting from the entities defined in Part 3 of the DICOM standard, we explored how the classes defined there can be integrated into a common data model of the electronic patient record implemented by the HIS (Hospital Information System). Based on the IODs we investigated the definitions and semantics of entities being relevant for structured recording of image data. RESULTS: Because semantic definitions are incomplete, a proposal is made for the core domain of structured radiologic service recording. Its definition of semantics goes beyond the application domain of radiologic imaging to avoid structural conflicts during HIS/RIS/PACS integration. Differentiation between treatment and billing provides an independent temporal mapping of services concerning medical and billing aspects. Two groups of radiologic services are distinguished: radiologic imaging and additional services. CONCLUSION: The incomplete definition of IOD semantics leads to potential conflicts during system integration. Complete covering of this topic is necessary for implementation of the electronic patient record.     

Contrast mapping and evaluation for electronic X-ray images on CRT display monitor

Simple chest X rays on film are the most common type of image in medical diagnosis. However, amongst the various types of medical X-ray images, they require the highest level of display quality due to the fact that the body structures they capture on film have varying degrees of permeability to X rays. Conventional high-definition digital display technology has not always been able to match the quality of such film images. This has been a major impediment against progress toward the complete digitization of simple chest X rays. The intent of this paper is to examine that, when applied to medical diagnosis of chest X rays, super-high-definition (SHD) images (digital images with resolution exceeding that of HDTV) are capable of producing a level of quality of diagnostic accuracy on a par with conventional film images. We will start out by seeking out the overall transmission characteristics of a system that uses digital radiography and a film digitizer to digitize images. We will then derive gray-scale transform characteristics based on the luminance linear method for approximating, as closely as possible on a CRT, film images on a light box that have wide dynamic range and high luminance. Finally, we will present the results of image evaluation experiments using high-definition CRT monitors. These results indicate that conventional film images and those on super-high-definition CRT monitors have nearly the same quality. They will also show that the contrast mapping selected by radiologists and theoretical luminance linear characteristics were almost the same except in low-luminance regions. We will also discuss radiologists' comments on CRT monitors after they participated in the evaluation experiment.     

Simultaneous leukaemic infiltrate and cholesteatoma in the same temporal bone

An otherwise healthy 37-year-old man came to the emergency room with left-sided dull chest pain of 4 weeks' duration. Physical examination, laboratory studies, and electrocardiogram were all unremarkable. A chest x-ray film revealed calcified pulmonary nodules. Computed tomography of the chest confirmed bilateral parenchymal cavitary lesions. Via limited thoracotomy, a tan nodule measuring 2.5 to 3.0 cm in diameter was excised from the left upper lobe. Histopathologic examination revealed a well circumscribed lesion and extensive lamellar hyalinization. A few foci of finely granular calcification were present within the hyalinizing areas. After surgery and short-term use of nonnarcotic analgesics, the chest pain resolved. Although pulmonary hyalinizing granuloma (PHG) is known to produce cavitating lesions, calcification at multiple sites is also consistent with this diagnosis. Clinicians should remember to include PHG in the differential diagnosis of multiple pulmonary nodules.     

A model for calculating the costs of in vivo dosimetry and portal imaging in radiotherapy departments

The costs of in vivo dosimetry and portal imaging in radiotherapy are estimated, on the basis of a detailed overview of the activities involved in both quality assurance techniques. These activities require the availability of equipment, the use of material and workload. The cost calculations allow to conclude that for most departments in vivo dosimetry with diodes will be a cheaper alternative than in vivo dosimetry with TLD-meters. Whether TLD measurements can be performed cheaper with an automatic reader (with a higher equipment cost, but lower workload) or with a semi-automatic reader (lower equipment cost, but higher workload), depends on the number of checks in the department. LSP-systems (with a very high equipment cost) as well as on-line imaging systems will be cheaper portal imaging techniques than conventional port films (with high material costs) for large departments, or for smaller departments that perform frequent volume checks.     

Computed tomography, magnetic resonance imaging, and digital radiography

There are three milestones in the history of thoracic radiology. Thoracic radiology started in 1897 when Williams developed thoracic fluoroscopy and introduced the basic concepts of roentgenologic interpretation. At the same time, the first chest films were performed allowing decisive improvement in the diagnosis of many chest diseases. Continuous technical improvement is responsible for the fact that, even today, the conventional chest film remains a highly accurate and frequently used imaging modality. A third milestone was the development of digital radiography and its use in the chest. Computerised tomography changed thoracic imaging dramatically; in a first step mainly as a tool to visualise soft tissue abnormalities and, later on, also as a modality to study lung disease. The recent development of the digital chest radiograph has again added new perspectives to the approach and diagnosis of chest disease.     

The radiographic evaluation of sinonasal tumors: an overview

It is axiomatic that advances in head and neck imaging improve our understanding of head and neck diseases. Dramatic improvements in radiologic imaging in recent years have, as a corollary, dramatically improved our understanding of sinonasal tumors. Older techniques such as plain film radiography and multidirectional tomography poorly delineate normal anatomy and pathologic changes in the craniofacial region. Modern imaging modalities depict sinonasal tumors and their metastases in detail, yielding information that allows treatment planning to proceed rationally. The radiologic examination is commonly employed as a precise "map" for implementation of therapy, and imaging studies are essential in the follow-up evaluation for tumor residual or recurrence. This article provides an overview of the current contributions made by head and neck radiology to the understanding and clinical management of sinonasal tumors.     

Evaluation of a high-density scintillating glass for portal imaging

One of the main factors that limits the performance of T.V. camera-based portal imaging systems is the poor light-collection efficiency of the lens and T.V. camera. An x-ray detector that produces more light per incident x ray would help overcome this limitation. We have been evaluating a high-density (3.8 g/cm3), thick (12 mm) glass scintillator for its suitability as an x-ray detector for T.V. camera-based portal imaging systems. The light output and spatial resolution of the glass scintillator has been compared to that of a copper plate/phosphor screen detector using radiographic film and the T.V. camera of our portal imaging system. The film measurements show that the light output of the glass scintillator is 82% of that of the copper plate/phosphor screen, while the T.V. camera measurements show that this value is 48%. A theoretical model of light transport described in this paper suggests that this discrepancy is due to refraction at the glass-air interface. Our measurements of the modulation transfer function (MTF) show that the spatial resolution obtained with the glass scintillator is similar to that obtained with the copper plate phosphor screen. However, the spatial resolution obtained with the glass scintillator decreases as the angle of x-ray incidence increase; this decrease, which is not observed for the copper plate/phosphor screen detector, is due to the large thickness of the glass scintillator. Due to the limited light output and the variable spatial resolution, the transparent glass scintillator, in its current form, is not suitable for portal imaging.     

Diagnostic considerations in patients with suspected coronary artery anomalies

The diagnosis of coronary artery anomalies requires a high index of suspicion during the history and physical examination. Nonspecific presentations are common, although dramatic presentations such as myocardial infarction or aborted sudden death will occur. Typically the results of the physical examination and ECG and the chest x-ray film are normal except with ALCAPA or coronary-artery fistulas. Screening studies such as exercise stress testing have low sensitivity, and a negative evaluation does not rule out the presence of a significant anomaly. These important limitations must be considered. Echocardiography is a practical and frequently diagnostic test if specific attention is paid to the coronary arteries. This examination should be performed in most patients with suspect symptoms. Other noninvasive techniques such as nuclear and cine MRI cardiac imaging may become increasingly important, but their current use is anecdotal. Cardiac catheterization remains the gold standard; however, recognition of important clues and specific angiographic views are required to fully delineate many anomalies.     

Localised carcinoma of the prostate: a paradigm of uncertainty

The incidence and prevalence of prostate cancer is increasing. A number of aetiological factors including age, race, family history and diet have been implicated. The majority of patients present with disease which is amenable only to palliation. Digital rectal examination, serum prostate-specific antigen and transrectal ultrasound can lead to a prostatic biopsy. Transrectal ultrasound, magnetic resonance imaging, bone scan and a chest X-ray are used for staging. The management of localised cancer is shrouded in uncertainty. Three options exist, watchful waiting, radiotherapy, and radical total prostatectomy. The published data are inadequate for a valid comparison of these, and none has been shown to offer an advantage. Surgery, and to a lesser degree radiotherapy, have a significant morbidity. It is hoped that through better understanding our management of this disease will improve.     

MRI and ultrasound in rheumatology

Technical innovations and software improvements in magnetic resonance imaging (MRI) and high-resolution sonography (US) have definitely influenced the diagnostic imaging of rheumatic diseases. For MRI, improvements in surface coils, dedicated low-field systems (0.2 T), and software improvements (shorter acquisition times and refinements of fat suppressing techniques) must be mentioned. For sonography, the main innovations concern the development of higher transducer frequencies (7-15 Mhz) and power Doppler imaging. Clinical evaluations have shown that MRI and US are most useful in cases of suspected rheumatic disease with negative plain film radiographs and for documenting the course of the disease, diagnosing of early rheumatoid arthritis, making a differential diagnosis in clinically unclear rheumatic diseases, investigating vascularization, and quantifying pannus formation. In order to improve diagnostic efficacy the role of MRI and US in the management of patients with rheumatic disease should be reconsidered.