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Gastrointestinal Imaging |
1 From the Department of Radiology, Hospital of the University of Pennsylvania, 3400 Spruce St, Philadelphia, PA 19104. Received June 4, 2003; revision requested August 14; revision received September 22; accepted October 22. Address correspondence to M.S.L. (e-mail: marc.levine@uphs.upenn.edu).
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ABSTRACT |
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 TOP ABSTRACT INTRODUCTIONMATERIALS AND METHODSRESULTS DISCUSSIONREFERENCES |
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MATERIALS AND METHODS: The survey consisted of questions about small-bowel follow-through (SBFT) examinations, including frequency of overhead radiographs, use of fluoroscopic spot images, personnel performing fluoroscopy, practice settings, and degree of specialization. By using a standard sampling technique, the country was divided into nine regions, and one state from each region was randomly selected. The survey was mailed to 452 full-time chief technologists. The responses were tabulated, and statistical analysis of the data was performed with the 
2 test.
RESULTS: Completed questionnaires were returned by 236 (52%) of 452 chief technologists; 219 (93%) respondents, 176 (80%) in private and 43 (20%) in academic groups, indicated that their group performed SBFT studies. The studies were performed by general radiologists in 205 (94%) of the 219 groups and by gastrointestinal or abdominal radiologists in 11 (5%). Studies included overhead radiographs in all 219 groups, with spot images of the terminal ileum in 201 (92%). Thirty (14%) of 219 groups routinely obtained spot images of the remaining small bowel, 104 (48%) obtained spot images only if there were questionable findings on overhead radiographs, and 82 (37%) obtained no spot images. Eighteen (8%) of 219 groups performed peroral pneumocolon examinations and 80 (37%) performed enteroclysis.
CONCLUSION: The majority of radiology groups perform SBFT studies. Regardless of the practice setting, these studies usually consist of a series of overhead radiographs, with routine spot images of the terminal ileum but not of the remaining small bowel. This approach may need to be reassessed in light of the American College of Radiology standards that all accessible small-bowel loops be visualized at fluoroscopy with representative radiographs to optimize the diagnostic yield of the examination.
© RSNA, 2004
Index terms: Intestines, radiography, 74.1271 • Radiologic Technologists • Radiology and radiologists
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INTRODUCTION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTS DISCUSSIONREFERENCES |
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The small-bowel follow-through (SBFT) study consists of a series of overhead abdominalradiographs obtained at regular intervals after the patient ingests a large volume of barium sulfate. Leading experts on radiologic examination of the small bowel recommend that this study include routine fluoroscopic imaging of the small bowel, with manual palpation to better visualize abnormal segments of the small bowel that might otherwise be hidden by overlapping loops on the overhead radiographs (3–5). The American College of Radiology (ACR) also recommends routine fluoroscopy with compression of all accessible small-bowel loops (6). Nevertheless, our impression has been that many radiologists rely primarily on overhead radiographs, with fluoroscopic spot imaging only of the terminal ileum after the colon has filled with barium.
To our knowledge, there are no available data about the practice patterns for radiographic examination of the small bowel in the United States. In 1987, findings of a survey of gastrointestinal radiologists revealed that the overall volume of barium studies of the small bowel has gradually declined during a 12-year period, but the authors did not evaluate the actual techniques used to perform these examinations (7). Thus, the purpose of our study was to survey academic and private radiology groups in the United States to obtain an understanding of the current practice patterns for radiographic examination of the small bowel.
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MATERIALS AND METHODS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTS DISCUSSIONREFERENCES |
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Site Selection
We conducted an anonymous mail survey of chief radiology technologists from different parts of the United States during the fall of 2002. For the purposes of the survey, we used a standard sampling technique in which the country was divided into nine regions, as determined by the Census Bureau (www.census.gov. Accessed August 21, 2002), with one state selected randomly from each region. The states selected were California, Colorado, Georgia, Indiana, Kentucky, Massachusetts, Minnesota, New York, and Texas. A search of the database of the American Registry of Radiologic Technologists from these nine states revealed a total of 452 full-time chief technologists certified in radiography. After reviewing our survey protocol, the American Registry of Radiologic Technologists released the names and addresses of these 452 chief technologists, but no other data about their radiologic practices were provided.
We chose to survey chief technologists rather than radiologists with the assumption that they are more likely to have a detailed working knowledge of the overall practice patterns of their groups and are also more likely to provide unbiased data about these practice patterns. Although some chief technologists may not have been personally familiar with all of the techniques discussed in the survey, they had the opportunity to consult with radiologists in their practices if they had questions. Also, we assumed that chief technologists with little or no working knowledge of the logistic details of performing radiologic examinations of the small bowel would be less likely to complete the questionnaires.
Survey
All of the authors contributed to the construction of the one-page questionnaire for the chief technologists about the practices of their groups concerning barium studies of the small bowel. If the surveyed technologists indicated in response to the first question that their groups did not perform barium studies of the small bowel, they were asked to return the surveys without responding to any of the remaining questions. If their groups did perform barium studies of the small bowel, however, they were asked to complete the entire questionnaire.
The major portion of the survey consisted of a series of questions about SBFT studies, including the frequency of acquisition of overhead radiographs (every 30 minutes or more or less often than every 30 minutes), the timing of the interpretation of the overhead radiographs (while the study was in progress or after the study was completed), the use of fluoroscopic spot images of the terminal ileum or the remaining small bowel (routine, selective, or not at all), the type of fluoroscopic equipment (conventional vs digital), the personnel who performed the fluoroscopy (radiologists vs technologists), and whether the upper gastrointestinal tract was also evaluated as part of the SBFT examination. Respondents were also asked to estimate whether the volume of SBFT examinations performed by their groups had changed compared with the volume 5 years earlier and whether their groups performed enteroclysis examinations (small-bowel enemas) or peroral pneumocolon examinations. Finally, the surveys included demographic questions about the nature of the practice settings (academic vs private practice) and the degree of specialization of the radiologists (general radiology vs gastrointestinal or abdominal imaging). The overall design of the survey was based on published recommendations on the optimal methods for preparing mailed surveys (8).
The surveys were mailed by one author (A.S.H.) to all 452 chief technologists with an accompanying introductory letter and a stamped self-addressed return envelope containing first-class postage. One month after the first mailing, a second round of surveys was mailed by the author to those chief technologists who failed to respond to the initial mailing. Each survey had a numbered identification tag that was used to formulate the repeat mailing list for nonrespondents. These identification tags were separated from the survey on receipt of the questionnaires to ensure anonymity of the participants.
Data Tabulation
The returned questionnaires were tabulated (A.S.H.) to determine the frequency of various responses to our survey questions. Any responses that were not clearly marked or did not precisely follow the directions were excluded from the analysis. For the question about the personnel performing the fluoroscopy, some respondents indicated that fluoroscopic spot images were obtained by both radiologists and technologists, so we included this option as a possible response.
Statistical Analysis
The data were analyzed (A.S.H.) for all of the respondents and then stratified and reanalyzed for academic versus private practice. A statistical analysis of the latter data was performed by using the 2 test (Excel; Microsoft, Bellevue, Wash) (9). P values of less than .05 were considered to indicate a significant difference.
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RESULTS |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTS DISCUSSIONREFERENCES |
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Radiographic Techniques for Small-Bowel Examination
The practice patterns of the respondents for radiographic examination of the small bowel are summarized in Table 2. All 219 respondents whose groups practiced small-bowel radiology indicated that SBFT studies were performed. One hundred thirty-one (60%) of the 219 respondents indicated that the upper gastrointestinal tract was routinely evaluated during SBFT examination, 84 (38%) indicated that it was not, and four (2%) left this question blank. Eighteen (8%) of the 219 respondents indicated that their groups performed peroral pneumocolon examinations as an adjunct to SBFT examination, 190 (87%) indicated that their groups did not, five (2%) left this question blank, and six (3%) placed a question mark in the designated space, presumably to denote lack of familiarity with this technique. Sixty-three (29%) of the 219 respondents indicated that the volume of SBFT studies performed by their groups had increased compared with the volume 5 years earlier, 73 (33%) indicated that the volume had decreased, 72 (33%) indicated that the volume was unchanged, and 11 (5%) indicated they were uncertain or left this question blank. Finally, 80 (37%) of the 219 respondents indicated that their groups performed enteroclysis examinations (small-bowel enemas), and 139 (63%) indicated that their groups did not.
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One hundred thirty-six (62%) of the 219 groups performed fluoroscopy of the small bowel only with digital equipment; 72 (33%), only with conventional equipment; and 11 (5%), with a combination of digital and conventional equipment. The spot images were obtained by radiologists in 155 (71%) of the 219 groups, by technologists in 34 (15%), and by a combination of radiologists and technologists in 28 (13%). No spot images were obtained in the remaining two (1%) groups.
Comparison of Academic and Private Groups
When the responses were stratified on the basis of the practice setting, we found significant or near significant differences between academic and private groups for the following parameters: Eight (19%) of 43 respondents from academic groups indicated that the studies were performed by radiologists specializing in gastrointestinal or abdominal imaging versus three (2%) of 176 from private groups (P < .001); 34 (79%) of 43 respondents from academic groups indicated that fluoroscopy was performed only with digital equipment versus 102 (58%) of 176 respondents from private groups (P = .013); and 31 (74%) of 42 respondents from academic groups indicated that the upper gastrointestinal tract was routinely evaluated during SBFT studies versus 100 (58%) of 173 from private groups (P = .057). We found no significant or near significant differences between academic and private groups for any of the other surveyed parameters, including the percentage of groups who obtained routine fluoroscopic spot images of the small bowel other than the terminal ileum versus the percentage who obtained spot images only if there were questionable findings on the overhead radiographs and the percentage who obtained no spot images.
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DISCUSSION |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTS DISCUSSIONREFERENCES |
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All respondents in our survey whose group practiced small-bowel radiology indicated that SBFT studies were performed as the primary technique for radiographic examination of the small bowel. Two hundred one (92%) of the 219 respondents whose group performed SBFT studies indicated that the overhead radiographs from such studies were routinely supplemented with fluoroscopic spot images of the terminal ileum, but 186 (85%) indicated that their group did not routinely obtain spot images of the small bowel other than the terminal ileum. When the responses were stratified on the basis of the practice setting, we found no significant differences between academic and private groups in the frequency of small-bowel fluoroscopy during this procedure. Our findings conflict sharply with the recommendations of the leading experts in small-bowel radiology that SBFT studies routinely include fluoroscopic spot imaging (with thorough compression of accessible small-bowel loops) to improve the detection of a variety of small-bowel abnormalities that may not be demonstrated on overhead radiographs (3–5). Our findings also diverge from the ACR standards for performing SBFT studies, which call for fluoroscopic compression of all accessible small-bowel loops with representative radiographs (6).
In a retrospective study by Maglinte et al (10) of lesions missed at SBFT examination, most such cases were found to result from technical errors in which the lesions could not be visualized on overhead radiographs and no spot images of the diseased small-bowel segments were obtained. The authors concluded that such errors could be decreased with intermittent fluoroscopic imaging of the small bowel with manual palpation to visualize diseased small-bowel segments hidden by overlapping loops on the overhead radiographs (10). Additional investigation is needed to determine the validity of this claim and to further elucidate the usefulness of fluoroscopic spot imaging for SBFT studies. If such study findings confirm the value of fluoroscopy, radiologists may need to reassess their policy of relying primarily on overhead radiographs for the evaluation of the small bowel without the benefit of fluoroscopic spot images.
Of the 216 respondents who provided information about the degree of specialization of the radiologists performing SBFT studies in their groups, 205 (94%) indicated that these studies were performed by general radiologists rather than by radiologists specializing in gastrointestinal or abdominal imaging. This finding may be partly explained by the demographics of our survey, as 176 (80%) of the 219 surveyed groups were in private practice, and it would be unusual to have such a high degree of specialization for radiologists in the private sector. However, only eight (19%) of the 43 respondents whose group was in academic practice indicated that SBFT studies were performed by radiologists specializing in gastrointestinal or abdominal imaging. This surprising observation could reflect a growing shortage of gastrointestinal or abdominal radiologists at academic medical centers. Whatever the explanation, it should be recognized that most SBFT studies are not being performed by radiologists who specialize in gastrointestinal or abdominal imaging.
Our survey revealed that SBFT studies are being performed almost twice as frequently with digital fluoroscopic equipment as with conventional equipment. Digital equipment has increasingly been preferred over conventional equipment, presumably because of such advantages as rapid image acquisition, electronic storage of images, and integration with a computerized workstation and picture archiving and communication system (11).
The peroral pneumocolon examination is sometimes used as an adjunctive technique for SBFT studies when the distal ileum has not been adequately visualized with these examinations. After intravenous administration of 1.0 mg of glucagon, a catheter is inserted into the rectum, and air is insufflated as the patient is rotated to reflux air from the colon into the distal ileum via the ileocecal valve (12). The peroral pneumocolon examination has been shown to improve the detection of aphthoid ulcers in Crohn disease or other abnormalities in the terminal ileum that might otherwise be missed at SBFT examination (12,13). Nevertheless, only 18 (8%) of the 219 respondents in our survey whose group performed SBFT studies indicated that peroral pneumocolon examinations were performed. It is unclear whether the low utilization of this technique is related primarily to a lack of technical skills for performing the procedure, a low demand for the procedure, or both. In any case, we believe that in selected cases, it would be beneficial for radiologists to take greater advantage of the peroral pneumocolon examination as an adjunct to SBFT examination. Technical information for performing this procedure is readily available in current textbooks of gastrointestinal radiology (4,5).
Results of our survey also revealed that enteroclysis examinations (small-bowel enemas) were being performed by only 80 (37%) of the 219 groups performing barium studies of the small bowel, and no significant difference was found between academic and private groups in the performance of enteroclysis. The infrequent use of enteroclysis both in academic and private practice settings may be related to several factors, including inadequate training of radiologists in the technical aspects of enteroclysis and the reluctance of some patients to undergo this procedure. Whatever the reason, enteroclysis has not been utilized to nearly the extent advocated by some experts in small-bowel radiology (3–5,14).
It is important to consider the limitations of this investigation. The response rate for our survey was 52%. Although this rate may seem low, a review of published surveys in medical journals found that the mean response rate for mail surveys to health-care workers other than physicians was 56% (SD ± 24%) (15). Our survey therefore had a response rate comparable to that of other mail surveys of this type. Nevertheless, we cannot rule out potential nonresponder bias among those who failed to return either mailing of the survey.
We recognize that there may be a subset of radiologists who perform intermittent fluoroscopy of the small bowel other than the terminal ileum without obtaining spot images unless abnormalities are seen. This represents another potential limitation of our survey, as we specifically asked whether SBFT examinations included fluoroscopic spot images rather than fluoroscopy per se in the absence of spot images. In any case, the ACR standard for the performance of SBFT studies indicates that "representative radiographs" of the small bowel should be obtained even "if no abnormality is identified" (6).
It should also be recognized that this was a self-reported survey, so some respondents could have modified their responses about preferred techniques for radiographic examination of the small bowel to place their practices in the best possible light. We tried to minimize such self-reporting bias by selecting chief radiologic technologists rather than radiologists as our target audience. This decision was based on the assumption that chief technologists were more likely to provide unbiased data about the practice patterns of their groups because of less familiarity with the ACR standards or published guidelines of experts for performing SBFT studies. On the other hand, some chief technologists may have been less familiar with the technical aspects for performing these studies than others, potentially leading to inaccurate responses.
We also compared respondents from practice settings that were disproportionately represented in our survey (176 [80%] private groups vs 43 [20%] academic groups). However, we believe that these proportions reflect the breakdown of private and academic groups practicing small-bowel radiology in the United States. Finally, our failure to observe significant differences between academic and private groups in some aspects of the practice of small-bowel radiology could have been related to inadequate sample sizes, a common methodological limitation in studies of this type (16).
In conclusion, the majority of radiology groups perform SBFT studies. Regardless of the practice setting, these studies usually consist of a series of overhead radiographs, with routine spot images of the terminal ileum but not of the remaining small bowel. This approach may need to be reassessed in light of the ACR standards that all accessible small-bowel loops be visualized at fluoroscopy with representative radiographs to optimize the diagnostic yield of this examination.
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ACKNOWLEDGMENTS |
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FOOTNOTES |
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Author contributions: Guarantor of integrity of entire study, M.S.L.; study concepts, A.S.H., M.S.L., I.L.; study design, A.S.H., M.S.L.; literature research, A.S.H.; data acquisition, A.S.H.; data analysis/interpretation, A.S.H., M.S.L.; statistical analysis, A.S.H.; manuscript preparation, A.S.H.; manuscript definition of intellectual content, A.S.H., M.S.L.; manuscript editing, revision/review, and final version approval, all authors
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REFERENCES |
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TOPABSTRACTINTRODUCTIONMATERIALS AND METHODSRESULTS DISCUSSIONREFERENCES |
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This article has been cited by other articles:
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  M. S. Levine, S. E. Rubesin, and I. Laufer Pattern Approach for Diseases of Mesenteric Small Bowel on Barium Studies Radiology, November 1, 2008; 249(2): 445 - 460. [Abstract] [Full Text] [PDF]
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