Migration of central lines from the superior vena cava to the azygous vein.

AIM: To report 11 cases of central venous access catheters migrating from the superior vena cava to the azygos vein in order to raise radiologists' awareness of this possibility. MATERIALS AND METHODS: This is a retrospective review of the clinical history and imaging of 11 patients whose central line migrated from the superior vena cava to the azygos vein. The time course of migration, access route of the catheters, outcome, and depth of placement in the superior vena cava were evaluated. RESULTS: All of these catheters were placed from the left; six through the subclavian vein, four as PICC lines, and one from the left internal jugular vein. Seven of the catheters were originally positioned in the superior vena cava. Four of the catheters were originally positioned in the azygos vein and were repositioned into the superior vena cava at the time of placement. The time to migration ranged from 2 to 126 days, average 43 days. In three cases, the migration was not reported at the first opportunity, resulting in a delay in diagnosis ranging from 10 to 27 days. All but one of the catheters extended at least 3.5 cm (range 1.8-7 cm) below the top of the right mainstem bronchus when in the superior vena cava. CONCLUSION: Risk factors for migration into the azygos vein include placement from a left-sided approach and original positioning in the azygos vein with correction at placement. The depth of placement in the superior vena cava was not a protective factor. It is important to recognize migration because of the elevated risk of complications when central lines are placed in the azygos vein.

RadStation: client-based digital dictation system and integrated clinical information display with an embedded Web-browser.

RadStation is a digital dictation system having an integrated display of clinical information. The three-tiered system architecture provides robust performance, with most information displayed within one second after a request. The multifunctional client tier is a unique client/browser hybrid. A Web browser display window functions as the client application's data display window for clinical information, radiology reports, and laboratory and pathology results. RadStation provides a robust platform for digital dictation functionality. The system's internal status checks ensure operational integrity in a clinical environment. Also, the programmable dictation microphone and bar-code reader supplant the mouse as the system's primary input device. By merging information queries into existing work flow, radiologist's interpretation efficiency is maintained with instant access to essential clinical information. Finally, RadStation requires minimal training and has been enthusiastically accepted by our radiologists in an active clinical practice.

Radiologist's clinical information review workstation interfaced with digital dictation system.

Efficient access to information systems integrated into the radiologist's interpretation workflow will result in a more informed radiologist, with an enhanced capability to render an accurate interpretation. We describe our implementation of radStation, a radiologist's clinical information review workstation that combines a digital dictation station with a clinical information display. radStation uses client software distributed to the radiologist's workstation and central server software, both running Windows NT (Microsoft, Redmond, WA). The client system has integrated digital dictation software. The bar-code microphone (Boomerang, Dictaphone Corp, Stratford, CT) also serves as a computer input device forwarding the procedure's accession number to the server software. This initiates multiple queries to available legacy databases, including the radiology information system (RIS), laboratory information system, clinic notes, hospital discharge, and operative report system. The three-tier architecture then returns the clinical results to the radStation client for display. At the conclusion of the dictation, the digital voice file is transferred to the dictation server and the client notifies the RIS to update the examination status. The system is efficient in its information retrieval, with queries displayed in about 1 second. The radStation client requires less than 5 minutes of radiologist training in its operation, given that its control interface integrates with the well-learned dictation process. The telephone-based dictation system, which this new system replaced, remains available as a back-up system in the event of an unexpected digital dictation system failure. This system is well accepted and valued by the radiologists. The system interface is quickly mastered. The system does not interrupt dictation workflow with the display of all information initiated with examination bar-coding. This system's features could become an accepted model as a standard tool for radiologists.

Integration of radiologist peer review into clinical review workstation.

Professional peer review of random prior radiologist's interpretations is mandated by the Joint Commission on Accreditation of Healthcare Organizations (JCAHO). The JCAHO expects documentation of 5% rate of random peer-review cases. Countless hours are spent in departments fulfilling these requirements. The integration of the peer-review process into the radiologist's interpretation workflow was expected to increase the percentage of documented peer review, yet decrease the time and effort for this documentation. radStation clinical review workstations are deployed at every reading station. When a requisition is bar-coded, radStation retrieves the patient's clinical information and automatically displays the prior comparison report. If the radiologist agrees with the prior report, a single click on a "quality assurance' agree box documents the agreement. In the case of a discordance, an additional dialog box automatically appears and the radiologist enters the reason for disagreement and then submits the case as a discrepancy. The system holds the discordance for 3 to 5 working days, then notifies the original radiologist via E-mail that a prior interpretation has been submitted for peer review, lists the submitted discrepancy reason, and provides a link to display the discordant report. The peer-review database is separate from the existing radiology information system (RIS). At the end of every month, summary reports of all peer-review activity are generated automatically. Initial benchmarks of our deployed system anticipate documentation of long-term random peer-review rate at greater than 50% of interpreted cases. The system enhances the peer-review process by integrating it with the normal interpretation workflow. The time to complete peer review using radStation is less than 1 second per normal case and less than 60 seconds for a discordant case. The E-mail notification system is fully automated, eliminating the need for secretarial involvement in the data collection. This system has completely replaced a manual paper-based system. The integration of peer review directly into the radiologist's interpretation workstation greatly enhances the capability to easily exceed JCAHO standards. The overall increase in peer-review documentation should continue to improve the ability to document a consistent high quality of patient care.

E-mail access to NetCME: implementation of server push paradigm.

We describe the implementation of a Continuing Medical Education project which utilizes e-mail delivery of HTML documents to facilitate participant access to case material. HTML e-mail is displayed directly within the e-mail reader of the Netscape browser. This system of proactive educational content delivery ensures simultaneous distribution to all participants. Although a more effective method of content distribution, the system preserves user confidentiality and maintains security. HTML e-mail is non-proprietary and could be integrated into existing Internet-based educational projects to facilitate user access.

A 40-year-old man with "stabbing" right-side chest pain.

The following case is presented to illustrate the roentgenographic and clinical findings of a condition of interest to orthopedic surgeons. The initial history, physical findings, and roentgenographic examination are found on the first page. The final clinical and roentgenographic diagnosis is presented on the following pages.

Radiology CME on the Web using secure document transfer and internationally distributed image servers.

We describe the implementation of a World Wide Web-based Continuing Medical Educational (CME) program in Diagnostic Radiology which allows accumulation of Category I credit. The program implements an unknown case presentation format which includes multiple choice questions, didactic information, and literature references with links to abstracts. Physician participation is anticipated to occur in brief sessions during which the program automatically tracks CME credit accumulation. To allow an interactive presentation, HTML electronic form documents are created "on the fly" by a Common Gateway Interface (CGI) application interfacing with several relational databases. The system is scalable with bandwidth intensive image transfers distributed over multiple internationally distributed image servers. For CME participants, the system utilizes documents encryption to ensure confidential physician interactions.

An analysis of sagittal spinal alignment in 100 asymptomatic middle and older aged volunteers.

STUDY DESIGN: A radiographic evaluation of 100 adult volunteers over age 40 and without a history of significant spinal abnormality was done to determine indices of sagittal spinal alignment. OBJECTIVES: To determine the sagittal contours of the spine in a population of adults older than previously reported in the literature and to correlate age and overall sagittal balance to other measures of segmental spinal alignment. SUMMARY OF BACKGROUND DATA: Previous studies of sagittal alignment have focused on adolescent and young adult populations before the onset of degenerative changes that may affect sagittal alignment. METHODS: Radiographic measurements were collected and subjected to statistical analysis. RESULTS: Mean sagittal vertical axis fell 3.2 +/- 3.2 cm behind the front of the sacrum. Total lumbar lordosis (T12-S1) averaged -64 degrees +/- 10 degrees. Lordosis increased incrementally with distal progression through the lumbar spine. Lordosis at L5-S1 and the position of the apices of the thoracic and lumbar curves were most closely correlated to sagittal vertical axis. Increasing age correlated to a more forward sagittal vertical axis with loss of distal lumbar lordosis but without an increase in thoracic or thoracolumbar kyphosis. CONCLUSIONS: The majority of asymptomatic individuals are able to maintain their sagittal alignment despite advancing age. Loss of distal lumbar lordosis is most responsible for sagittal imbalance in those individuals who do not maintain sagittal alignment. Spinal fusion for deformity should take into account the anticipated loss of lordosis that may occur with age.

Anterior fresh frozen structural allografts in the thoracic and lumbar spine. Do they work if combined with posterior fusion and instrumentation in adult patients with kyphosis or anterior column defects?

STUDY DESIGN: This was a prospective study of 24 adult patients with kyphosis or anterior column spinal defects treated with anterior fresh frozen allograft for anterior column defects and posterior instrumentation and autogenous grafting. OBJECTIVES: The objectives of the study were to assess the effectiveness of the anterior allograft in maintaining sagittal correction and to assess anterior incorporation. SUMMARY OF BACKGROUND DATA: Twenty-four patients were followed for a minimum of 2 years (range, 2 + 0-5 + 4 years). METHODS: Upright radiographs were analyzed before surgery, immediately after surgery, and at the final follow-up examination to assess success of anterior fusion and maintenance of correction. A strict four-point grading system was used. Two independent observers analyzed the radiographic results. RESULTS: Only two patients showed some collapse of their anterior allograft. The other 22 patients maintained correction, attaining a Grade I or Grade II fusion. Semiconstrained instrumentation ws used posteriorly in the two patients who had graft collapse. CONCLUSIONS: Anterior structural allograft worked effectively to maintain correction of kyphosis if combined with posterior instrumentation and autogenous grafting. Rigid forms of posterior instrumentation were preferred.

Principles and imaging of spinal instrumentation.

This articles focuses on the principles of spinal surgery, the basic types of spinal instrumentation, and imaging of the postoperative spine. It is the first of three articles in this issue that discuss the spine. Complications are discussed and illustrated throughout. This article should assist radiologists in the review of spinal, chest, and abdominal films of spinal surgery patients.

Fixation techniques and instrumentation used in the cervical spine.

This article emphasizes the techniques and instrumentation used in the cervical spine to provide insight into the identification and function of the fixation, grafting, and wiring techniques used for stabilization and fusion. Fracture reduction and stabilization in degenerative disease, the most common reasons for spinal fixation in the cervical spine, are discussed, as are infections, spinal stenosis, and tumors.

Fixation techniques and instrumentation used in the thoracic, lumbar, and lumbosacral spine.

The radiologist is faced with continual changes in both surgical techniques and instrumentation for the spine. To properly evaluate radiographic and special imaging studies, it is necessary to have a working knowledge of the devices used and the principles that direct their use. This article discusses the identification and function of the most common instrumentation in the thoracic, lumbar, and lumbosacral spine.

The Internet, World-Wide Web, and Mosaic: an overview.

Technology is revolutionizing education. Global networks, powerful personal computers, and user friendly, graphically oriented software are creating a new infrastructure that promotes rapid, efficient access to information. Images, text, audio, and video can be integrated into interactive multimedia presentations, providing a hierarchy of knowledge that can be traversed by the click of a mouse. The extensive use of images in our arena makes radiologic education a major beneficiary. Because the components (text, images) of educational presentations are stored electronically on a network rather than on the printed page, an individual component can be linked and bundled into as many different presentations as desired. Furthermore, components of information can exist on different computers throughout the world and yet be linked by software into a single presentation.

A method for interactive medical instruction utilizing the World Wide Web.

We describe the implementation of interactive medical teaching programs in radiology and histology which utilize the Internet's World Wide Web (WWW). The WWW standard hypertext interface allows for simple navigation between related documents but does not provide a method for student tracking or question queries. Electronic forms, a recent feature of the WWW, provide the means to present question documents to remote clients and track student performance. A feature of our approach is dynamic creation of HTML documents based upon interaction with database applications. The approach allows multiple simultaneous, yet asynchronous interactions by geographically dispersed students upon the same instructional database and is scalable, providing the capability for multiple image/document servers. The security of the database is assured given that it is not accessible through the Internet.

Evaluation of the injured cervical spine: comparison of conventional and storage phosphor radiography with a hybrid cassette.

PURPOSE: To compare conventional and storage phosphor radiography of the injured cervical spine. MATERIALS AND METHODS: Sixty-five patients underwent imaging in a supine position while wearing a cervical collar. Matched storage phosphor and conventional lateral cervical spine radiographs were obtained with an 18 x 24-cm hybrid cassette. Edge-enhanced and nonenhanced copies of each computed radiograph were printed on film, and the images were sent via a computer network to a remote imaging workstation. Four radiologists read the conventional radiographs, the two hard-copy computed radiographs, and the soft-copy images and used a binary scale to score the visibility of bone and soft-tissue structures. RESULTS: All readers scored better in all areas with computed radiographs, and a statistically significant (P = .030) improvement in performance was seen for soft-tissue structures. CONCLUSION: Storage phosphor imaging offers advantages over conventional radiography, and digital images may be a viable alternative to film.

Fractures of the tibial plateau: value of spiral CT coronal plane reconstructions for detecting displacement in vitro.

OBJECTIVE: The purpose of this in vitro study was to determine the value of spiral CT for detecting displacement of fractures of the tibial plateau. The exact amount of inferior plateau depression, if any, is a primary criterion for deciding between surgical management and conservative management. MATERIALS AND METHODS: An artificial fracture was produced in a cadaveric tibial plateau. Inferior displacements of 0, 1, 3, and 5 mm were created at the fracture. Spiral CT scans of each displacement were obtained with table speeds of 2, 3, and 5 mm/sec. Section collimation equaled table increment. Coronal image reconstructions were produced by use of standard scanner software. The images were interpreted by six musculoskeletal radiologists. RESULTS: Interpretation accuracy was greatest with coronal images created from the 2 mm/sec scans. For distinguishing 5-mm fracture displacements, the average diagnostic sensitivity and specificity were 96% and 93%, respectively; when a 2-mm depression was used as the criterion for clinical significance, the sensitivity was 100% and the specificity was 69%. CONCLUSION: When minimal table increment and collimation are used, spiral CT can detect clinically important inferior depressions of tibial plateau fractures. On the basis of the results of this study, when spiral CT is used for tibial plateau fracture assessment, we recommend 2-mm section collimation, 2-mm table speed, and reconstruction of images at 1-mm increments.

Comparison of spiral computed tomography versus conventional computed tomography multiplanar reconstructions of a fracture displacement phantom.

PURPOSE: The capabilities of spiral computed tomography (CT) versus conventional CT to represent minimal fracture displacements on multiplanar reconstruction images in a phantom model were evaluated. MATERIALS AND METHODS: A displacement phantom was created from Teflon and was scanned with conventional and spiral CT, at slice collimations of 2 mm, 3 mm, and 5 mm. Three Z-axis interpolation algorithms (360_LI, 180_LI and 180_HI) were employed to process the spiral image data into planar images. Displacements of 5 mm or less were represented in the phantom, and the resultant multiplanar reconstructions were analyzed for the precision of displacement representation. Specifically, the edge profiles of the reconstructed images were measured and compared. RESULTS: Spiral CT reconstruction edge profiles were similar to those of conventional CT when minimal table increments (3 mm/sec or less), and an advanced interpolation algorithm (180_LI) was employed. Images obtained with 360_LI interpolation manifested the effect of widened slice profile even when employing minimal table speeds. CONCLUSIONS: With minimal table increment (3 mm/sec or less) and a high-order interpolation algorithm (180_LI), spiral-CT-derived reconstructions demonstrate similar edge profile resolution to reconstructions obtained from conventional CT.

Helical CT: principles and technical considerations.

The performance of helical CT requires several user-defined parameters that exceed the requirements of conventional CT. One needs to carefully select the collimation, table increment, and reconstruction interval. Minimizing these parameters maximizes longitudinal resolution but with various trade-offs. Decreasing the collimation decreases the effective section thickness but increases pixel noise. Limiting the table increment to a pitch of 1 limits the broadening of the effective section thickness associated with the helical technique but also limits the coverage that can be achieved with a given helical scan. Our general practice is to minimize the collimation to cover the volume of interest and to accept a pitch up to 2, provided that we are using 180 degree interpolation. The reconstruction interval is also minimized to maximize longitudinal resolution but with trade-offs of increased image processing time, data storage requirements, and physician time for image review. For routine diagnosis, we recommend reconstruction of one to two sections per table increment, and, for multiplanar and three-dimensional imaging, we recommend at least three sections be reconstructed per table increment. The scan duration is dictated by both patient and machine factors.