Small Bowel Imaging Research Articles

MDCT of small bowel tumours.

Primary benign and malignant neoplasm of the small bowel are rare. Malignant tumours often present late symptoms resulting in a poor prognosis. Early detection of small bowel neoplasms is desirable but challenging for both clinicians and radiologists. Conventional double contrast enteroclysis was the method of choice in small bowel imaging but is increasingly being replaced by cross-sectional imaging methods as computed tomography (CT) and magnetic resonance imaging (MRI). Multidetector CT (MDCT) produces high-resolution cross-sectional imaging of the abdomen and the small bowel. It allows multiplanar visualisation of small bowel tumours, demonstrates signs of small bowel obstruction as well as the mural and extramural extent of small bowel malignancies. This aids planning for surgical resection. In addition, liver metastases or peritoneal seeding can be detected with CT. The best visualisation of small bowel neoplasms is achieved with CT enteroclysis or enterography and this review discusses these techniques and MDCT characteristics of small bowel tumours.

Role of capsule endoscopy in inflammatory bowel disease

Capsule endoscopy (CE) is an innovative technological breakthrough that for the first time provides a noninvasive method to obtain high-resolution imaging of the entire small bowel. Since its recent inception, the diagnostic utility of CE has become well established for the evaluation of diverse ulcerative and inflammatory disorders of the jejunum and ileum. The incredible resolution of its lens (0.1 mm) detects focal villous edema or atrophy, denuded, as well as ulcerated mucosal lesions missed by other imaging techniques. CE has been shown by meta-analysis to be a more sensitive method to investigate patients for small bowel Crohn's disease, with an incremental yield above 30% versus other imaging modalities. In patients with indeterminate colitis, CE is useful in distinguishing between ulcerative and Crohn's colitis. Among patients with established Crohn's disease, CE may be employed to determine: (1) the extent and severity of small bowel involvement, (2) postoperative recurrence, (3) post-therapy mucosal healing, and (4) whether active small bowel inflammatory lesions exist in the clinical setting of functional bowel disorder. Complications are rare and include capsule retention at stricture sites. The new patency capsule can diminish the risk of the latter problem in at-risk patients. CE can also serve as a guide to sites that require biopsies or dilatation by push or double-balloon enteroscopy. However, other causes of small bowel lesions may mimic Crohn's disease. A standard terminology system has thus been developed, and a CE Crohn's disease severity scoring index is currently undergoing validation studies.

Darmdiagnostik – Kapselendoskopie

The small bowel has ever since been the "black box" of endoscopy. The long distance from mouth to anus limits the use of conventional endoscopy for the multiple complex looped configurations. For some years now the new technology of wireless capsule endoscopy allows the endoscopic imaging of the complete small bowel. After ingestion of a small pill-size video capsule a continuous series of images is transmitted to an external recorder, whose data can be reviewed after completion of the examination. Compared to other diagnostic tools like push-enteroscopy, capsule endoscopy proves higher diagnostic yield for the detection of bleeding sources in obscure gastrointestinal bleeding. Its results for this task seem to be comparable to those of intraoperative endoscopy, so far considered as gold standard. Capsule endoscopy also opens up new horizons in diagnosing different small-bowel affections like Crohn's disease and polyposis syndromes. Complication rate is low, the main problem being the entrapment of the capsule in a previous unknown stricture which limits its use in Crohn's disease considerably. To date capsule endoscopy needs further evaluation in respect to outcome and cost-effectiveness in order to confirm its role as an important diagnostic tool for the small bowel.

The role of imaging in small bowel disease

A successful small bowel imaging strategy depends on choosing the right investigation to answer the right clinical question. Barium studies are readily available, reproducible, easy to perform, consistent and currently the workhorse in the investigation of small bowel disease. CT enteroclysis (CTE) and MR enteroclysis (MRE) provide both luminal and extraluminal information during a single examination. MRE, in particular, is a low radiation dose study and an attractive imaging option when investigating Crohn's disease in young patients. Wireless capsule endoscopy (WCE) is considered more sensitive than barium and CT for small mucosal lesions and obscure gastrointestinal (GI) bleeding. Radionuclide studies are best employed when a specific diagnosis is suspected. The small bowel represents the most challenging part of the alimentary canal to image. A successful imaging strategy is dependent on using the most appropriate radiology to answer the right clinical question. A number of conventional imaging strategies, such as barium follow-through, have been successfully used to characterize small bowel pathology, but newer techniques, including CT enteroclysis or MR enteroclysis (CTE or MRE) and wireless capsule endoscopy (WCE), have been introduced and are gaining popularity. The purpose of this review is to describe and fully illustrate the different imaging modalities and techniques currently available in the investigation of small bowel disease. We will assess the strengths and weaknesses of each test and highlight their most appropriate use.

Gastrointestinal bleeding

Interest in technical developments related to small-bowel imaging has been reflected in the number of abstracts dealing with the use of capsule endoscopy and double-balloon enteroscopy in gastrointestinal bleeding; the enthusiasm is still growing. For peptic ulcer bleeding, the surprisingly still high rates of recurrent bleeding, in spite of technological advances, still motivates clinicians to study the various factors that may influence the outcome and determine the way in which centers can adhere to practices that are based on the best available evidence. Concerns relating to the outcome of glue injection for bleeding gastric varices appear to be unjustified so far. There are still uncertainties relating to the endoscopic diagnosis and treatment of gastric antral vascular ectasia, as reflected in some studies.

Gradient-enhanced volume rendering: an image processing strategy to facilitate whole small bowel imaging with MRI

MRI of the small bowel with positive contrast from orally administered contrast agent is a promising non-invasive imaging method. The aim of our study was to introduce small bowel MRI in a display format that clinicians are accustomed to and that maximizes the amount of information visualized on a single image. Twelve healthy volunteers, median age 32 years (range 18-49 years) participated in the study. A mixture of 20 ml Gd-DOTA (Dotarem), 0.8 g/kg body weight psyllium fibre (Metamucil) and 1.2 l water were sequentially administered over a period of 4 h. Imaging was performed on a 1.5 T unit (Philips Gyroscan, Intera). Fat-saturated, 3D, gradient echo imaging was performed while the patient was in apnea (30 s). Bowel motion was reduced with 40 mg intravenously administered scopolamine (Buscopan). A 3D, gradient-enhanced, volume rendering technique was applied to the 3D data sets. Standard projections [left anterior oblique (LAO), right anterior oblique (RAO), supine and prone] resembling conventional enteroclysis were successfully generated within fewer than 10 min processing time. Reconstructions were reproducible and provided an entire overview of the small bowel. In addition thin-slab volume rendering allowed an overlap-free display of individual structures. Positive contrast from orally administered contrast agent, combined with a gradient enhanced volume rendering method, allows the reconstruction of the small bowel in a pattern resembling conventional double-contrast enteroclysis. Segmental display without overlay is possible.

Double-balloon endoscopy: Extending the arm of the gastroenterologist

Double-balloon endoscopy: Extending the arm of the gastroenterologist

Capsule endoscopy indications

Commentary Capsule endoscopy (CE) is an exciting new advance in GI-tract imaging. It has expanded our view to include the small bowel, which was historically inaccessible to traditional endoscopes. This unique technology has caught the interest of the public and the lay press. Although its best-defined role is in small-bowel imaging in patients with obscure GI bleeding, other indications are emerging. Dr Glenn Eisen has reviewed the current status of the small-bowel capsule and its newer relative, the esophageal capsule. Current and potential future indications for these exciting technologies are discussed. – Grace H. Elta, MD, Editor

Comparison of Image Quality of Two Different Capsule Endoscopy Systems

Background: Small bowel imaging using the Given Diagnostic System with the Pillcam™ SB Capsule Endoscope is well established. A new capsule Endoscopy system, the Olympus Capsule Endoscope System “Endo Capsule” has recently been launched. There is currently no published data on direct comparison between the 2 systems. Aim: To compare the quality of images obtained from the 2 capsule endoscopy systems. Methods: The 2 systems were compared using images from test charts and images obtained from patients during actual capsule endoscopy. The charts were as follow: (1) Color chart with different tones of red; (2) Resolution chart; (3) 50 Euro bill (small letters at the left lower edge that cannot be read without the help of a magnifying glass); (4) Images of the digestive tract obtained from 2 patients who underwent examination using both systems. All images were reviewed by a gastroenterologist experienced in performing capsule endoscopy (US). Results: 1. Color chart: Olympus “Endo Capsule”: very realistic colors easily obtained due to automatic adjustment of lighting; Pillcam™ SB Capsule Endoscope: very realistic colors could be obtained but was difficult because there was no automatic adaptation of lighting. 2. Resolution chart: The Olympus “Endo Capsule” had at least 5 times more maximum resolution than the Pillcam™ SB Capsule Endoscope. 3. 50 Euro Bill: With the Olympus “Endo Capsule” the letters could be recognized but with the Pillcam™ SB Capsule Endoscope, small letters can not be identified. 4. Images of the digestive tract: Olympus “Endo Capsule”: the appearance of the “landscape” pattern, folds, polypoid lesions, discoloration as well as the visualization of mucosal pattern was excellently; the form of the villi could be distinguished (eg. short and wide vs. long and slim). Pillcam™ SB Capsule Endoscope: the appearance of the “landscape” pattern, folds, polypoid lesions, discoloration was good but the mucosal pattern and villi at the periphery were not always well visualized. Conclusions: Preliminary comparison of the two available capsule endoscopy systems shows equal quality of colors, an effective automatic lighting present in the Olympus system only and a significantly better resolution in the Olympus system. Larger lesions of the digestive tract are shown with a satisfactory quality using both systems. However, the assessment of mucosal pattern was better with the Olympus system.

Effect of Erythromycin On Transit Time in Video Capsule Endoscopy: A Randomized Prospective Placebo Controlled Trial

Purpose: Video Capsule Endoscopy (VCE) has revolutionized the field of small bowel imaging. However, the reported incompletion rate is high, ranging from 23-35%. The majority of incomplete exams are due to failure of the capsule to reach the cecum within the battery life of eight hours. Erythromycin, a motilin agonist, has been shown in previous studies to be effective in treatment of diabetic gastroparesis and reducing orocecal transit time. Several recent reports have revealed conflicting results in the use of erythromycin and improvement of completion rate for VCE. We conducted a randomized prospective placebo controlled trial in evaluating the effect of erythromycin in gastric and small bowel transit time in VCE. Method: 20 consecutive patients underwent VCE in ambulatory setting were randomly assigned into two groups. Patients were excluded if they were allergic to erythromycin, taking coumadin or digoxin, or pregnant. One group received erythromycin 250 mg orally an hour prior to VCE. The other group received placebo. All patients were prepped with 2L golytely 12 hours prior to VCE. The gastric, small bowel, and total transit time were recorded. Patients were requested to fill out a questionnaire immediately after VCE regarding symptoms of nausea, vomiting, and diarrhea, which were recorded in a scoring system (0-10) ranging from none to severe. Results: In the erythromycin group, gastric transit time was significantly shorter compared to the placebo group (mean of 12.1 min vs 37.0 min, p < 0.05). However, the small bowel transit time (262.5 min for erythromycin vs 244.7 min for placebo) and total transit time (274.6 min vs 281.7 min) were not significantly different between the two groups. All patients had completed exam with capsule reaching cecum in time. There was no significant difference in the symptom scores between the two groups. Conclusions: Erythromycin 250 mg orally one hour prior to VCE significantly decreased the gastric transit time, but had no significant effect on small bowel and total transit time. It was overall well tolerated. We therefore suggest a low threshold in the use of erythromycin prior to VCE in patients with risk factors for delayed gastric emptying.

Video capsule endoscopy of the small bowel (PillCam SB)

It is 4 years since capsule endoscopy was first introduced. This disposable 27 mm x 11 mm video capsule containing its own optical dome, light source, batteries, transmitter and antenna is swallowed with water after a 12 h fast. The capsule is propelled via peristalsis through the gastrointestinal tract, capturing about 60 000 digital images and is excreted naturally. In a relatively short period, capsule endoscopy has become an important investigative tool in patients with occult gastrointestinal bleeding, suspected small bowel tumors and other abnormalities. The aim of this review is to update the reader with the main indications, performance and complications of the technique. There are some clear indications for capsule endoscopy: occult gastrointestinal bleeding, suspected small bowel tumor, suspected Crohn's disease, surveillance of inherited polyposis syndromes, drug-induced small bowel injury or any abnormal small bowel imaging. Problematic areas include defining what are normal findings and the inability to take biopsies and thus differentiate between entities. Capsule endoscopy has become a first-line tool to detect abnormalities in the small bowel, and is superior to all other imaging technologies. Its interplay with the new technique of double balloon enteroscopy enables the small bowel to receive proper attention, similar to other gastrointestinal organs.

Enteroclisi-TC multistrato

The authors illustrate the technique for small-bowel imaging using enteroclysis with multidetector-row computed tomography (MDCT), underscoring the important role played by CT in the assessment of the small bowel thanks to the advent of first the spiral and later the multidetector technique. The paper makes a detailed comparison of the various methods that have been used in CT study of the small bowel and proposes a standardised technique to achieve correct distension of bowel loops and adequate evaluation of bowel wall vascularity, making reference to the well-consolidated experiences of the various Italian research groups. The paper accurately describes the different procedures required for CT assessment of the small bowel, from nasojejunal intubation to the selection of the most appropriate acquisition phases for assessment of bowel wall vascularity.

Crohn disease of the small bowel: MR enteroclysis versus conventional enteroclysis

Enteroclysis has been suggested as the technique of choice for the evaluation of Crohn disease of the small intestine. Adequate distention of the entire small bowel with barium suspension allows the radiologic demonstration of mucosal abnormalities and provides functional information by defining distensibility or fixation of the small bowel loops. The principal disadvantage of conventional enteroclysis is the limited indirect information on the state of the bowel wall and extramural extension of Crohn disease, and its effectiveness may be hindered owing to overlapping bowel loops. Moreover, the radiation dose administered to patients, mostly at a young age, should be considered. Magnetic resonance (MR) enteroclysis is an emerging technique for small bowel imaging and was introduced to overcome the limitations of conventional enteroclysis and MR cross-sectional imaging by combining the advantages of both into one technique. MR enteroclysis has the potential to change how the small bowel is assessed because of the functional information, soft tissue contrast, direct multiplanar imaging capabilities, and lack of ionizing radiation.

Internal fistulas in Crohn disease: magnetic resonance enteroclysis

Internal fistulas (IFs) and abscesses are the most common complications of Crohn disease (CD). To reliably diagnose and clearly distinguish inflammatory or fibrostenotic manifestations of CD from its complications is of paramount importance to appropriately guide therapeutic decisions. Magnetic resonance enteroclysis (MRE), a recently introduced technique for small bowel imaging, has proved a high efficacy in the depiction of luminal and extraluminal manifestations of CD and holds great promise as a powerful diagnostic tool in the comprehensive diagnostic workup of this disease. As of yet, the characteristic imaging appearance of IFs on MRE has not been described in detail. This article reviews the performance of conventional imaging techniques and the current potential of MRE in the depiction of IFs in CD. Typical imaging morphology and characteristic imaging findings of IFs on MRE are described in detail and a newly defined and highly indicative imaging finding, the "star-sign," is presented and discussed.

Small bowel imaging- a rapidly changing field and a challenge to radiology

There was a time when the small bowel follow-through (SBFT) was the primary method of diagnosing diseases of the small intestine. Enteroclysis was reinvented in the 70's and with the SBFT remained the dominant methods of investigating the mesenteric small intestine to the late 90's. Since the introduction of the first commercial computed tomography (CT) scanner in 1973, the ability of monoslice CT to diagnose different causes of intestinal obstruction and inflammatory bowel diseases emerged. The introduction of helical CT technology in 1989 and subsequently multichannel CT further changed small bowel imaging. Faster acquisition of a large volume of data with thinner collimation allowed multiplanar reformatting a distinct advantage in evaluating an organ which is longer than wide. The introduction of magnetic resonance (MR) imaging with its increased soft tissue contrast, lack of ionizing radiation, and the ability to acquire ultrafast sequences has made MR imaging an important tool in small bowel imaging (1).

Crohn Disease of the Small Bowel: Preliminary Comparison among CT Enterography, Capsule Endoscopy, Small-Bowel Follow-through, and Ileoscopy

To prospectively compare four diagnostic small-bowel imaging techniques for depiction of abnormal findings in the same patients known to have or suspected of having Crohn disease. Institutional review board approval and informed consent were obtained. Patients known to have or suspected of having nonobstructive Crohn disease were recruited. Each patient underwent capsule endoscopy, computed tomographic (CT) enterography, colonoscopy with ileoscopy, and small-bowel follow-through (SBFT). Findings consistent with Crohn disease were tabulated for each imaging examination (diagnostic yield). The proportions of patients with positive findings at each examination were compared, and any significant differences between the tests were calculated by using the exact McNemar test. Seventeen patients (nine women, eight men; mean age, 49 years; range, 18-78 years) completed the study out of 20 patients enrolled. Crohn disease was depicted by capsule endoscopy in 12 patients (71%), ileoscopy in 11 (65%), CT enterography in nine (53%), and SBFT in four (24%). Ileoscopy was incomplete in four patients, and capsule endoscopy was incomplete in two patients. Capsule endoscopy had the highest diagnostic yield for Crohn disease, and SBFT had the lowest, but these differences were not statistically significant (P = .02). SBFT failed to depict a stricture in one patient, which resulted in surgical removal of the capsule. CT enterography and SBFT depicted extraintestinal findings (eg, mesenteric adenopathy in two patients, perianal and enterocolic fistulas in one patient) not detected endoscopically. This preliminary study demonstrates capsule endoscopy and CT enterography may depict nonobstructive Crohn disease when techniques such as ileoscopy and SBFT have negative or inconclusive findings.

Capsule Endoscopy in Gastrointestinal Lymphomas

Capsule endoscopy (CE) is a new procedure for small-bowel imaging. The potential contribution of this method to the diagnosis and staging of gastrointestinal lymphomas has not yet been evaluated. The aim of this prospective study was to assess the frequency and morphology of different forms of intestinal pathology in patients with gastrointestinal lymphomas. Commercially available capsule video endoscopes were administered to 27 patients (16 men and 11 women, aged 27-77) with known gastrointestinal lymphomas. CE was also carried out in 30 control individuals. All seven patients with primary intestinal lymphomas who were examined were found to have pathological findings on CE--four with ulcerations, four with nodes, three with villous atrophy, and one with plaques/white villi. One patient with severe diarrhea was examined three times before and after chemotherapy, and improvement of the lesions was evident, as well as resolution of diarrhea. Twenty patients with gastric lymphoma were examined (16 with low-grade and four with high-grade B cell lymphomas). The capsule did not leave the stomach in three patients, suggesting impaired motility. The small-bowel transit times were 261+/-41 min for intestinal lymphoma, 245+/-62 min for gastric lymphoma, and 224+/-82 min for controls (P>0.05). Five of the 20 patients with gastric lymphoma had pathological findings in the intestine--three with plaques/white villi, two with nodes, and two with villous atrophy. In two patients, subsequent biopsies revealed secondary follicular lymphoma and high-grade lymphoma, respectively. CE is a valuable diagnostic tool for defining the extent of bowel involvement and assessing the efficacy of treatment in patients with gastrointestinal lymphoma.

CT enteroclysis: technique and clinical applications

CT enteroclysis (CTE) has been gradually evolving with technical developments of spiral and multidetector row CT technology. It has nowadays become a well-defined imaging modality for the evaluation of various small bowel disorders. Volume challenge of 2L of enteral contrast agent administrated to the small bowel via a nasojejunal catheter ensures luminal distension, the prerequisite for the detection of mural abnormalities, also facilitating the accurate visualization of intraluminal lesions. CT acquisition is centered on small bowel loops, reconstructed in thin axial slices and completed by multiplanar views. Image analysis is essentially done in cine-mode on work-stations. CTE is of particular diagnostic value in intermediate or advanced stages of Cohn's disease, including the depiction of extraintestinal complications. It has become the imaging modality of choice for the localization and characterization of small bowel tumors. The cause and degree of low-grade small bowel obstruction is more readily analyzed with the technique of CTE than conventional CT. Limitations of CTE concern the assessment of pure intestinal motility disorders, superficial mucosal lesions and arteriovenous malformations of the small bowel, which are not consistently visualized. CTE should be selectively used to answer specific questions of the small bowel. It essentially contributes to the diagnostic quality of modern small bowel imaging, and therefore deserves an established, well-defined place among the other available techniques.

Capsule Endoscopy 2005: Results of the 2005 International Consensus Conference - Introduction

Capsule endoscopy has now been approved as a diagnostic device in Europe and North America. Over the past 4 years, application of this technology has increased dramatically and at present there are over 2500 systems in service throughout the world. Despite this worldwide acceptance of capsule endoscopy as the state-of-the-art method for small-bowel imaging, numerous issues remain. At the Fourth International Conference on Capsule Endoscopy (ICCE), held in March 2005, 127 leaders in the field from around the world were asked to develop a consensus in six different areas: intestinal preparations and prokinetics; obscure gastrointestinal bleeding; inflammatory bowel disease; celiac disease; esophageal capsule endoscopy; and capsule retention. Of these expert physicians, 48 % were from Europe, 37 % from North America, 10 % from Japan, 3 % from Australia, and 2 % from the rest of the world. Each of the six groups had an advisory panel that worked in advance of the conference to compile the evidence-based material for that particular field. Each of the panel members prepared an address on a topic related to the subject, which was delivered to the group as a whole at the meeting. The issues were then opened to general discussion. The design for the consensus was thus similar to that used by the United States National Institutes of Health for the development of a “white” paper. Over two days, approximately 25 physicians in each group met and discussed in depth the issues presented by each panel. Consensus was built, and the following papers detail each of the six groups’ work and findings.

Conventional enteroclysis with complementary MR enteroclysis: a combination of small bowel imaging

Conventional enteroclysis with complementary MR enteroclysis: a combination of small bowel imaging