Fluoroscopy: Image Quality and Analysis

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Fluoroscopy: Image Quality and Analysis

Anne Scott, BSRS, R.T.(R)

The diagnostic quality After completing this article, readers should be able to: of radiographic images  Describe the role of the radiographer and radiologist assistant in image quality and analysis. obtained during fluoroscopy  Identify the factors used to evaluate image quality. studies depends on multiple  Summarize the importance of proper positioning. factors, including patient  Discuss the effects of patient preparation on the resulting radiographic image. positioning, selection of  Differentiate between technical factors, procedural factors and equipment malfunctions that exposure technique, patient affect image quality. preparation, removal of artifacts and appropriate luoroscopic imaging typically is equipment, imaging standards have been use of image processing used to demonstrate real-time, developed to help ensure diagnostically equipment and software. dynamic processes; however, fluo- useful studies are produced, regardless roscopy equipment also can of the equipment configuration or image Fluoroscopy operators, F acquire static images if necessary to cap- recording device used. Standards pertain- including radiographers ture a permanent record of an anatomical ing to medical image quality are necessary and radiologist assistants, area or abnormality. Several types of to optimize the diagnostic usefulness of must be able to distinguish image recording technologies are available radiographs and to minimize radiation sources of error during for fluoroscopy, including spot film devic- exposure caused by repeat imaging exami- image acquisition and es, automatic film changers, photofluo- nations.2 Each imaging facility has its own determine ways to improve rography, digital fluorography, cine fluo- standards for acceptability; therefore, flu- image production and rography and video recording. Each oroscopy operators must be aware of their quality. Radiology personnel recording method has different character- individual organization’s requirements should follow established istics that affect image quality in terms of for performing repeat examinations, even departmental standards spatial resolution, contrast and noise.1 as they work to produce the best possible for image acceptance to Additionally, there are different images.3 prevent unnecessary repeat fluoroscopy equipment configurations High-quality images demonstrate the exposures and to provide designed for specific uses, including stan- following characteristics: the radiologist with the dard radiography/fluoroscopy combina-  Maximum recorded detail. most useful images for tion units, fixed C-arm units and portable  Optimum patient positioning. interpretation. C-arm equipment. Because each type  Excellent penetration, contrast and of equipment has distinct limitations, density. imaging personnel should receive specific  No motion or removable artifacts.3 training for their fluoroscopy systems and The radiographer or radiologist assis- the use of postprocessing tools to produce tant (RA) should examine all images for the best possible images.1 quality before they are submitted to the Despite the variety of fluoroscopy radiologist for interpretation.

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The Role of the Radiographer The Role of the Radiologist Assistant Radiographers may perform noninterpretive fluo- The ASRT Radiologist Assistant Practice Standards roscopic procedures and assist licensed practitioners defines an RA as, “an advanced-practice radiographer with fluoroscopic and specialized interventional who practices under the supervision of a radiologist imaging procedures, when appropriate and in accor- and enhances patient care in radiology service.”7 The dance with state statutes.4 The American College of RA exercises independent professional judgment when Radiology (ACR) suggests that technologists receive performing patient assessment, patient management and formal training in radiation management and complete procedures in medical imaging and interventional radiol- a formal credentialing process administered by the ogy, including fluoroscopy.7 facility for assisting with interventional procedures.5 According to the American Registry of Radiologic In the United Kingdom, radiographers frequently are Technologists (ARRT), a registered radiologist assistant trained to perform double contrast barium enema (R.R.A.) is responsible for evaluating images for com- examinations, and research reports that radiographers pleteness and diagnostic quality, as well as recommend- produce studies that are comparable to radiologist- ing additional images when necessary, as long as they are managed studies.6 obtained using the same modality. An RA also assesses According to the American Society of Radiologic images for diagnostic utility and reports clinical findings Technologists (ASRT) Radiographer Scope of Practice, and initial observations to the supervising radiologist. the technologist is responsible for the following parts of If there are exceptions to the expected outcome of a the medical imaging procedure: procedure, the RA must document those exceptions in  Reviewing the patient’s clinical history to ensure a timely, accurate and comprehensive manner and may the proper imaging procedure has been ordered. be required to devise a new plan of action to reach the  Preparing the patient for the procedure. intended outcome. If the RA develops a revised action  Selecting the proper imaging equipment and asso- plan, the RA must share the plan with the appropriate ciated accessories. radiology team members.7  Positioning patients to best demonstrate the anato- Part of the RA’s responsibility for ensuring image my of interest. quality is to confirm that equipment performance and  Immobilizing patients as necessary. maintenance meets the manufacturer’s specifications.8  Preparing and administering medications, such The RA may perform quality assurance activities as contrast agents, prescribed by a licensed to assess equipment performance and radiology practitioner. department processes. RAs also may be required to  Determining the radiographic exposure technique, document these activities and request equipment repair while applying principles of radiation protection to or maintenance.8 the patient and staff.4 In the United Kingdom, the trend for advanced Following image acquisition, the radiographer should radiographers has been to interpret diagnostic imaging evaluate the images before submitting them to the studies and report their impressions. One study found radiologist. Images should demonstrate proper patient that radiographers reported results of film-screen radi- positioning, appropriate anatomy and overall satisfactory ography in 46% of hospitals and barium enemas in 45% image quality, and the technologist should determine if of hospitals.9 It is important to note that the ACR, the additional images might improve the overall diagnostic ARRT and the ASRT do not support this trend.9 value of the procedure. If additional images are obtained, The ACR maintains that the RA may make initial the technologist must record the justification for the observations of diagnostic studies and forward those repeated images. Radiographers also should develop remarks only to the supervising radiologist,5 but RAs and maintain a technique chart for imaging equipment, may not perform interpretations of radiological exams.10 including fluoroscopy systems, to minimize repeats RAs, however, can communicate the radiologist’s find- caused by exposure error.4 ings to the referring physician.9,10

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