Radiol Oncol 2003; 37(2): 67-72.
Dedicated small bowel follow-through -experience of Clinical Institute of Radiology in Ljubljana
Mateja Kropivnik and Breda Jamar
Clinical Institute of Radiology, University Medical Centre, Ljubljana, Slovenia
Background. Small bowel is a difficult part of the alimentary tract to examine. Radiologic modality most commonly used has been the conventional small bowel follow-through (SBFT), which has often been done in a cursory manner, without fluoroscopy and manual palpation. The purpose of our study is to present ded-icated SBFT and to assess its sensibility and specificity.
Patients and methods. We analysed 35 dedicated SBFT, performed from April to September 2002, in pa-tients. Findings were evaluated according to clinical follow-up, endoscopy and surgery. Results. Our findings were consistent with clinical follow-up, endoscopy and surgery in 33 patients. In 2 patients our findings were false negative. Our results show 89.5 % sensitivity and 100 % specifity. Conclusions. An adequate per-oral examination remains the most reliable tool for diagnostic evaluation of the small bowel.
Key words: intestine, small - radiology; barium sulfate; enema; Crohn disease
Introduction
Small bowel is a difficult part of the alimen-tary tract to examine because of its anatomy. Proximal jejunum and the terminal ileum can also be examined by enteroscopy but the mesenteric small intestine is the part of ali-mentary tract in which radiologic examina-tions are dominant diagnostic procedures.1 The radiologic examinations of the small
Received 25 February 2003 Accepted 10 March 2003
Correspondence to: Breda Jamar, M.D., Clinical Institute of Radiology, University Medical Centre, Zaloška 7, 1000 Ljubljana, Slovenia; Email: breda.jamar@kclj.si
bowel include barium studies and newer im-aging methods: ultrasound (US), comput-erised tomography (CT) and magnetic resonance imaging (MRI).
For many years, the radiologic modality most commonly used to evaluate small bowel disease has been the conventional small bow-el follow-through (SBFT). After per oral intake of barium suspension, periodic overhead ra-diographs were made until the barium suspension reached the colon. Spot radiographs were obtained of the terminal ileum and any other areas of abnormality suggested on the overhead radiographs.2 Fluoroscopy and palpation were used sparingly or not at all.
For dedicated SBFT, larger amounts of barium suspension must be taken to fill all seg-
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ments of the small bowel. Careful fluo-roscopy, vigorous manual palpation and ap-propriate spot radiographs are routine com-ponents of the examination.
Enteroclysis, a double contrast examina-tion needs a intubation catheter with a guide-wire positioned just beyond the ligament of Treitz for direct injection of contrast medium into the jejunum.3 The injection should be fast enough to allow moderate distension without completely abolishing peristalsis.4 During the filling phase, the different loops are watched for mobility, distension and in-tegrity. Spot films are taken and an overview made when the whole small bowel is filled. Several variations are possible: single con-trast enteroclysis or air/water or methylcellu-lose insufflation for double contrast.5,6
Newer imaging methods are valuable tools in assessing intestinal wall and extraluminal involvement.
Gastrointestinal-related disease may be an occasional incidental observation on US ex-amination which should lead to appropriate further investigation.7 In experienced hands bowel US is an accurate technique for assess-ing extend and anatomical location of disease within the bowel.8
CT has the ability to depict pathology out-side the intestinal lumen and in this way con-tributes to the imaging of the small bowel dis-ease.7 The accuracy of small-bowel spiral CT studies depends on the presence of well dis-tended loops and  adequate  endoluminal
opacification.5
In spiral CT enteroclysis, the administration of water soluble iodinated contrast agent by intubation during fluoroscopy is needed.9
MR is not a primary imaging method for the small bowel. It is limited by the mobility of the bowel and by the lack of a reliable in-traluminal contrast agent.7 Owing to excel-lent soft tissue contrast and multiplanar im-aging capabilities, MR imaging could be the optimal imaging method for evaluation of small-bowel in the future.10
Radiol Oncol 2003; 37(2): 67-72.
The aim of our study was to assess the sen-sibility and specificity of detailed-dedicated SBFT, as performed at our department.
Patients and methods
From April to September 2002 92 dedicated SBFT were performed at the department of gastrointestinal radiology.
Of these, we analysed 35 consecutive pa-tients who were referred by gastroenterolo-gists because indications were more specific and follow-up was possible.
The average age of the patients was 42 years (range, 23-64 years), 14 were male and 21 female.
The referral diagnoses were: food allergy in 1 patient, abdominal pain in 2, abdominal pain with diarrhoea in 4, coeliac disease in 2, suspected Crohn’s disease in 16 and reactiva-tion of known Crohn’s disease in 10 patients.
Dedicated small bowel follow-through was performed with oral administration of 4x200 ml diluted barium suspension: 600 ml of water added to 200 ml of Micropaque. Fluoroscopy was done during the ingestion of the first 200 ml of barium. The oesophagus and the stomach were examined fluoroscopi-cally. The first spot radiograph was obtained when suspension reached the duodenojeju-nal flexure.
The patient was given the second glass of barium and after 15-20 minutes an overhead film was taken, and compression and palpation of all segments, filled with barium, was done during fluoroscopy. After the ingestion of the third and fourth glasses of barium all segments of small bowel were opacified in most cases, as well as the terminal ileum and the coecum. Motility was observed during flu-oroscopy and careful manual compression of the small bowel was done, before a spot film was taken, to document radiologic findings.
Our findings were evaluated according to clinical follow-up, endoscopy and surgery.
Kropivnik M et al. / Dedicated small bowel follow-through
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Results
We analysed 35 dedicated SBFT. Our results show 89.5% sensitivity and 100% specifity of dedicated SBFT. All of 17 patients with abnormal findings on SBFT were abnormal at confirmation method giving the proportion of correct diagnoses as 17/17 = 100% (positive predictive value). Similarly, among the 18 pa-tients with normal SBFT the proportion of correct diagnosis was 16/18 = 88.8% (negative predictive value) (Table 1).
Table 1. The accuracy of small bowel follow-through (SBFT)
SBFT	Abnormal	Normal   Total	
Abnormal findings Normal findings	17 2	0 16	17 18
Total	19	16	35
The patient with food allergy has normal findings on SBFT. Endoscopic examination and clinical diagnosis was dyspepsia.
In one case of suspected coeliac disease, thickened folds in duodenum were seen on SBFT. Erosive gastritis and duodenitis were found at gastroduodenoscopy. The patient with longstanding coeliac disease had radio-logic findings in the small bowel consistent with coeliac disease and lymphoma both con-firmed by histology.
Four patients with abdominal pain and di-arrhoea had normal radiologic findings. The absence of small bowel pathology was consis-tent with clinical follow-up.
Two patients had pain in the upper abdomen: in one case the compression of the third part of duodenum, caused by superior mesenteric artery, was found; in the second case, a 4 cm large diverticulum in the second part of duodenum was seen (Figures 1, 2).
Among 16 patients with suspicion of Crohn’s disease, the radiologic findings were positive in 5, the diagnosis was later con-firmed by endoscopy and biopsy. In 11 pa-tients with negative radiologic findings, en-
Figure 1. Compression of pars horisontalis duodeni by superior mesenteric artery.
Figure 2. Duodenal diverticulum.
doscopic findings were negative in 9, but in two coloileoscopy with biopsy showed in-flammatory changes in the terminal ileum (Figure3).
Ten patients had known Crohn’s disease and suspected reactivation. Five of them had previous surgery. In 4 ileotransversoanasto-Radiol Oncol 2003; 37(2): 67-72.
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mosis stenosis was found on SBFT, con-firmed by surgery. One patient had a resec-tion of terminal ileum. Inflammatory changes of distal ileum, seen on SBFT, were confirmed endoscopically (Figure 4). In 2 cases the find-ings on SBFT were normal; at coloileoscopy the inflammatory changes were seen in transversal part of large bowel, but terminal ileum
Figure 3. Crohn’s disease of the small bowel.
Figure 4. Crohn’s disease at ileotransverso-anastomot-ic site.
was normal. In 3 cases radiologic changes of Crohn’s disease were found in terminal ileum and our findings were confirmed on en-doscopy.
Discussion
The prevalence of small-bowel disease is low and the clinical diagnosis is difficult by non-specific symptoms and a low index of suspi-cion.1
In patients with non-specific abdominal complaints US is often the first examining method. The main drawback of US is insuffi-cient visualisation of intestinal lumen due to luminal collapse and presence of gas obscur-ing the underlying bowel.
The limitations of the radiologic investiga-tion of the small-bowel with oral contrast material have long been recognized.6
The dilemma between SBFT as more ac-ceptable to the patient, and the uncomfort-able intubation-infusion method (entero-clysis) has not been resolved.6
Disadvantage of the conventional SBFT is a risk of overlooking an important abnormal-ity, predominantly on overhead radiographs, which display the opacified small bowel as closely packed, overlapping loops. The major drawback is insufficient use of fluoroscopy and palpation.
Enteroclysis has been promoted as more accurate in the detection of early mucosal changes. The superiority of enteroclysis is controlled introduction of contrast material into the small bowel, luminal distension, small bowel hypotonia secondary to jejunal distension, relative rapidity of completion of the study, and the use of double contrast ma-terial.6 The disadvantages of enteroclysis is the lack of universal availability, higher radiation dose, discomfort during intubation and inability to examine for gastroduodenal dis-ease.
Carefully performed SBFT with frequent
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fluoroscopy, manual palpation and appropri-ate spot radiographs has been shown to achieve results comparable to enteroclysis.2
It has some advantages over enteroclysis because of its simplicity, near-universal avail-ability, a high level of patient tolerance, the opportunity to assess the gut in a relatively physiologic state of distension and distensi-bility, the possibility to evaluate the duode-num and a relatively low radiation dose to the
patient.11
The sensitivity of enteroclysis in suggested inflammatory bowel disease (IBD) was found to be higher in most of the studies.12 However, the specificity and the positive pre-dictive value was somewhat higher concern-ing dedicated follow through examination. Higher sensitivity of enteroclysis probably re-flects in a tendency to use it more frequently with specific symptoms of IBD. In the same way dedicated follow-through examination was probably used when symptoms were
non-specific.12
No gross differences were found in sensi-tivity, specificity or predictive values, when dedicated follow-through examination and enteroclysis were compared.4,12
In our study specificity was 89.5%, because our findings were false negative in two pa-tients. On retrograde evaluation the missed radiologic signs were attributed in one case to overlapping segments of distal ileum and in-sufficient palpation, in the second case the changes of Crohn’s disease were not specific on coloileoscopy, but confirmed by biopsy.
This indicates that the dedicated follow-through technique may be used for screening
purposes.12
Average skin entry radiation dose for ente-roclysis was 1.5 times greater than that for SBFT with upper gastrointestinal examina-tion and almost 3 times greater than for ded-icated SBFT.10
Enteroclysis is not indicated in young pa-tients with low suspicion of pathology.11
It should be borne in mind that bowel US
is highly operator dependent, requiring expe-rience and time to achieve accuracy rates comparable with those published in the liter-ature.8
The major disadvantages of CT and MRI are that these modalities are expensive and not universally available.
Factors to be considered when selecting the appropriate technique include the reason for the examination, the age of the patient, time and cost involved, patient acceptance, radiation exposure and accuracy.13
Conclusions
An adequate per-oral examination depends largely on the use of a dedicated small bowel technique, emphasising fluoroscopic observa-tion and spot radiographs of compression of all segments of small bowel.
The dedicated SBFT has a number of ad-vantages for use as a screening examination, including the need for less room and radiologist time, less radiation exposure and high sensitivity when the examination is carefully performed.
Conventional SBFT has no role in present-day small bowel radiology.
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