Current status of small bowel radiography

Multidetector-row computed tomography and 3-dimensional computed tomography imaging of small bowel neoplasms: current concept in diagnosis

The diagnosis of small bowel neoplasms can present a difficult challenge to the radiologist because the tumors are uncommon, often small, and may be difficult to detect radiographically. The most common small bowel neoplasms include adenocarcinoma, carcinoid, lymphoma, and gastrointestinal stromal tumors. The location and computed tomography (CT) appearance of the small bowel tumors may aid in the diagnosis. For instance, small bowel adenocarcinoma occurs more frequently in the duodenum and may result in obstruction. Carcinoid tumors are more common in the ileum and are typically hypervascular submucosal masses that produce a characteristic mesenteric mass when they spread to the mesenteric nodes. Lymphoma can occur anywhere along the gastrointestinal tract and have a variable CT appearance. It may appear as a single mass, multiple masses, an infiltrating lesion resulting in aneurysmal dilatation of the bowel, or as an exophytic mass. Gastrointestinal stromal tumors are more common in the jejunum and ileum and usually appear exophytic and bulky often with ulceration. Traditionally, small bowel series and enteroclysis have been used for imaging patients with suspected small bowel tumors. More recently, CT is beginning to play a more important role for this clinical indication. The thinner collimation possible with multidetector CT (MDCT) along with water as oral contrast and a good intravenous contrast bolus may improve the sensitivity of CT for detecting small bowel tumors. In addition, MDCT scanners improve the quality of the 3-dimensional CT (3D CT) images that are valuable to the clinicians and surgeons for surgical planning. It is important for the radiologist to be familiar with the CT appearance of these neoplasms and the potential role of MDCT and 3D imaging in their diagnosis and surgical planning.

Initial experience with capsule endoscopy at a major referral hospital

OBJECTIVES

To determine the utility of capsule endoscopy in patients referred for investigation of suspected disease of the small intestine.

DESIGN AND SETTING

Single centre, prospective, cohort study from 4 July 2001 to 8 September 2002.

PATIENTS

Sixty consecutive patients who underwent capsule endoscopy for investigation of suspected disease of the small intestine.

MAIN OUTCOME MEASURES

Abnormal findings at capsule endoscopy.

RESULTS

Examination of the entire small bowel was achieved in 46/60 patients (77%). Thirty-two of 47 patients (68%) referred with obscure gastrointestinal bleeding had positive findings. Seven of nine patients (78%) referred for investigation of suspected Crohn's disease had small bowel erosions or ulcers consistent with Crohn's disease. The capsule was not passed in one patient.

CONCLUSION

Capsule endoscopy is a novel, minimally invasive and useful tool for the investigation of the small intestine.

Wireless capsule endoscopy detects small bowel ulcers in patients with normal results from state of the art enteroclysis

BACKGROUND

Wireless capsule endoscopy (WCE) is a new technology for small bowel imaging.

AIM

To report our initial experience with sensitivity of high quality enteroclysis in patients with small bowel ulcers detected by WCE.

METHODS

Medical records of all patients referred for WCE from December, 2001 to April, 2002 at our institution were reviewed. All patients had negative upper and lower endoscopies and small bowel barium studies before WCE.

RESULTS

There were 40 patients (19 female, mean age 57.3 yr) during this study period. Three patients had multiple small bowel ulcers detected by WCE. One with ileal ulcers and abdominal pain had an enteroclysis at another hospital before WCE. Review of the study at our institution showed that it was of excellent quality and was normal. Two patients with chronic iron deficiency anemia had multiple small bowel ulcers and were referred after WCE for a repeat small bowel barium study by biphasic enteroclysis performed by experienced GI radiologists. The radiologists were told in advance of the WCE findings. Both studies were considered technically to be of perfect quality. Despite this, both studies were negative. All 3 patients improved after therapy for Crohn's disease.

CONCLUSIONS

Our data indicates that WCE may be more sensitive for small bowel ulcers than the best enteroclysis available.

Current concepts in imaging of small bowel obstruction

The diagnosis and treatment of small bowel obstruction continue to evolve. The imaging approach in the work-up of patients with known or suspected small bowel obstruction and the timing of surgical intervention in this disease have undergone considerable changes over the past two decades. This article examines the current concepts related to the use of imaging technology in the diagnosis and management of patients with small bowel obstruction. The meaning of frequently used but poorly defined terms in describing intestinal obstruction is clarified and illustrated.

Technical refinements in enteroclysis

As the primary method of investigating the small bowel, enteroclysis remains a technique in evolution. Technical refinements have made the examination faster to perform, better tolerated by patients, and easier to interpret. More recently, its essential principle of volume challenge has been combined with the tremendous advantage of CT cross-sectional imaging with multiplanar reformatting to give rise to the exciting new techniques of CT enteroclysis and MR enteroclysis (see separate reviews in this issue). Through improvements in methodology and advancements in technology, the future of enteroclysis looks bright indeed.

Multidetector-row helical CT enteroclysis

Currently, CT-E is not recommended as the first-line examination in patients when mucosal detail is required. Double-contrast barium air enteroclysis has advantages in demonstrating small mucosal abnormalities. The authors find CT-E of value in the work-up of patients with symptoms of intermittent small bowel obstruction, particularly those with a history of prior abdominal surgery; in the further work-up of selected patients with high-grade obstruction in whom general surgeons prefer initial conservative management (immediate postoperative small bowel obstruction, patients with history of prior abdominal surgery for malignant tumor, history of radiation treatment, and possible internal extraintestinal fistulae); in looking for complications of small bowel Crohn's disease; and in the patient with unexplained anemia or gastrointestinal bleeding. In a series of patients who had both abdominal CT and barium enteroclysis done, each examination provided unique and complimentary diagnostic information. Because CT-E combines the advantages of both methods of examination, is it the optimum imaging work-up in the investigation of small bowel disease? Further research and clinical experience will define the precise role of CT-E in the investigation of small bowel disease. Experience with this method of examination is limited to a few institutions, performed by investigators with interest in small bowel diseases. The addition of cross-sectional display and multiplanar reformatting made possible by multidetector-row helical CT to enteral volume change and the use of multifunctional nasointestinal catheters make CT-E an important tool in the investigation of small bowel disease. Experience has shown the increased reliability of any method of examining the small bowel that challenges intestinal wall distensibility by fluid enteral volume infusion.

A prospective trial comparing small bowel radiographs and video capsule endoscopy for suspected small bowel disease

BACKGROUND & AIMS

This study was undertaken to prospectively compare the clinical outcomes of small bowel radiographs with the wireless capsule endoscopy.

METHODS

Twenty-two patients were selected consecutively because of suspected small bowel disease. Two patients were excluded owing to ileal stenosis. Thus, the results of barium follow-through and the Given M2A wireless video capsule (Given Imaging Ltd., Yoqneam, Israel) endoscopy were compared in 20 patients (13 men; mean age, 52.5 yr; range, 29-78 yr).

RESULTS

Barium follow-through was normal in 17 patients and showed ileal nodularity in 3 patients. Capsule endoscopy was normal in 3 patients and showed positive findings in the remaining 17 patients. The barium study was considered diagnostic in 4 (20%) patients. The capsule endoscopy was considered diagnostic in 9 (45%) patients, suspicious in 8 (40%) patients, and failed in 3 (15%) patients. For obscure gastrointestinal (GI) bleeding, the diagnostic potential of barium follow-through was much worse as compared with the capsule endoscopy (5% vs. 31%, P < 0.05). Capsule endoscopy was well tolerated and better accepted by patients when compared with the most recently performed endoscopic procedure.

CONCLUSIONS

The video capsule endoscope was found to be superior to small bowel radiograph for evaluation of small bowel diseases. However, this novel wireless endoscope system needs further assessment because of limitations such as difficulties in interpretation of potentially nonspecific findings.

3D modeling and virtual endoscopy of the small bowel based on magnetic resonance imaging in patients with inflammatory bowel disease

RATIONALE AND OBJECTIVES

Small bowel MRI (MR imaging) is a new imaging modality that excellently depicts small intestine pathology in patients with inflammatory bowel disease. Virtual endoscopy based on sectional imaging is a recently introduced technique to create endoscopy like views. The aim of this study was to evaluate the feasibility of virtual small bowel endoscopy based on MR imaging in patients with Crohn disease.

MATERIALS AND METHODS

Thirty consecutive patients with Crohn disease were scanned after oral application of pineapple juice for contrasting the small bowel. Dedicated high resolution T1 weighted 3D-FLASH sequences with fat suppression were used for volume scanning. Volume-rendered 3D models of the small bowel were created and virtual endoscopy was performed. The feasibility and quality of this new visualization method was assessed.

RESULTS

In nine of 30 patients virtual endoscopy was considered as good quality (flight through the entire small bowel was possible, typical folds were revealed). In 18 patients fair quality (at least 4/5 of the small bowel were depicted adequately) was assessed. In three of 30 patients virtual endoscopy was not sufficiently possible because of inadequate bowel filling or breathing artifacts. Three fistulae diagnosed on 2D MRI were visualized on the virtual endoscopic view.

CONCLUSION

Virtual endoscopy of the small bowel is feasible based on high resolution MR imaging. Vivid insight views and 3D models provide an interesting addition to sectional MR findings.

Enteroclysis and computed tomography enteroclysis

Enteroclysis, the most detailed radiologic examination of the small bowel, can be a challenge for both patient and radiologist. This article broadly outlines the principal technical features of the standard enteroclysis procedure and discusses its diagnostic advantages and indications, as well as its limitations and difficulties. A comparative assessment of computed tomography-enteroclysis and the emerging magnetic resonance adaptation complements the survey of current approaches to radiologic small bowel diagnostics.

Preoperative evaluation by magnetic resonance imaging in patients with bowel obstruction

BACKGROUND

Bowel obstruction is a problematic condition because the main clinical issue is to determine whether emergency laparotomy or observation with a long tube is required. The recent development of imaging diagnostic modalities such as magnetic resonance imaging (MRI) is thought to be promising to support therapeutic decisions in patients with bowel obstruction.

METHODS

Twenty-seven patients with bowel obstruction who underwent laparotomy were evaluated by plain x-ray film, computed tomography (CT) scan, and MRI preoperatively with regard to the presence or absence of bowel obstruction, and the site and cause of bowel obstruction. Diagnostic accuracies were compared among these radiological modalities.

RESULTS

The presence of bowel obstruction was detected in 22 (81.5%) of 27 patients by plain abdominal x-ray film, in 24 (92.3%) of 26 patients by CT scan, and in 25 (92.6%) of 27 patients by MRI. The sites of obstruction were consistent with surgical findings in 25 (92.6%) of 27 patients by MRI, and in 15 (57.7%) of 26 patients by CT scan. The causes of bowel obstruction were accurately diagnosed by MRI in 25 (92.6%) of 27 patients, and in 23 (88.5%) of 26 patients by CT scan.

CONCLUSIONS

MRI could identify the presence and the site and cause of bowel obstruction in most of the cases. MRI is assumed to be superior to CT scan in the preoperative diagnosis of bowel obstruction.

Radiologic evaluation and staging of small intestine neoplasms

The small intestine is an uncommon location for neoplasms in either clinical or radiological practice. Because of its anatomic location and morphology, diagnosis of the diseases that affect small intestine pose difficulties. Symptoms are nonspecific and endoscopy is commonly unsatisfactory. Since early and definite diagnosis is crucial for prompt therapy, radiological imaging plays an essential role. Enteroclysis is the primary and effective radiologic modality in the evaluation of small bowel neoplasms. On the other hand, computed tomography should be the complementary radiologic method as well as for staging. In this review, the most common neoplasms of the small intestine and their common radiologic findings have been discussed.

Malignant melanoma: patterns of metastasis to the small bowel, reliability of imaging studies, and clinical relevance

OBJECTIVES

The aims of this study were to determine the frequency of different patterns of melanoma metastases to small bowel on radiological examination, and to assess the reliability of the most commonly used radiological methods for detecting these lesions.

METHODS

The records of cases archived as melanoma metastatic to the small bowel of the Armed Forces Institute of Pathology were reviewed. The clinical information, type of imaging procedure performed, and radiological features were analyzed and compared to the findings at surgery and at autopsy.

RESULTS

A total of 32 patients had clinical and surgical data with pathological confirmation. Seven patients had metastasis involving the duodenum, 22 had jejunal involvement, and 11 had ileal involvement. Metastases were categorized as polypoid, cavitary, infiltrating, or exoenteric. The polypoid pattern was seen in 20 patients (63%), six of whom showed multiple polypoid lesions (>10), referred to as polyposis. The "target lesion," a discrete polypoid mass with a central ulceration, was observed in only three (9%) of the 32 patients. Eight patients (25%) demonstrated a cavitary pattern, a circumferential mass with inner marginal necrosis, and five (16%) showed an infiltrating pattern. One patient (3%) had an exoenteric lesion with a fistulous tract. The small bowel follow-through demonstrated 32 of 55 metastases (sensitivity 58%). Contrast-enhanced CT demonstrated 32 of 48 masses (sensitivity 66%). Of the six cases of malignant polyposis, none were identified using CT, and only two were diagnosed by small bowel follow-through.

CONCLUSIONS

The polypoid pattern, equally distributed between the jejunum and ileum, is the most common manifestation of metastatic melanoma to the small bowel. The target lesion was infrequently seen in this series. Small bowel follow-through and conventional CT seem to be unreliable in demonstrating melanoma metastases to the small bowel.

Jejunoileal Causes of Overt Gastrointestinal Bleeding: Diagnosis, Management, and Outcome

Major bleeding from the small intestine is uncommon and difficult to localize. We examined its etiologies and assessed available diagnostic and therapeutic approaches. The records of all adults undergoing operation for small intestinal hemorrhage over a 10-year period (1/89–12/98) were reviewed. There were eight men and four women with a mean age of 54 years. Six patients presented with arteriovenous malformations. Preoperative diagnosis was by endoscopy (three of six), scintigraphy (two of two), and/or angiography (two of six). Intraoperative panendoscopy was used for localization in 5 cases. Three other patients had tumors (leiomyoma, leiomyosarcoma, and adenocarcinoma) by CT scan (two) and/or scintigraphy (two). All were resected but one patient died of recurrence. Two patients underwent resection of a Meckel's diverticulum, one after angiographic diagnosis. Another patient with Crohn's disease had a positive angiogram and colonoscopy before resection. There were no operative deaths but major morbidity occurred in five patients (42%) and hospitalization averaged 17 days. We conclude that jejunoileal lesions are a rare cause of intestinal bleeding but can be associated with substantial morbidity. Arteriovenous malformations and tumors remain the most common causes. An accurate diagnosis and definitive management depend on selective preoperative imaging and judicious operative exploration.

Role of conventional radiology in the diagnosis and staging of gastrointestinal tract neoplasms

Preoperative diagnosis and staging of primary gastrointestinal (GI) neoplasms are challenges for both clinicians and radiologists. Barium studies are very sensitive in disclosing primary malignancies, even at an early stage. Radiologic signs depend on the evolutional stage of the disease and its appearance on gross pathology. A neoplasm may be manifested on barium studies by a wide spectrum of findings, including mucosal abnormalities, mass presence, ulcerative lesions, submucosal infiltration, and lumen stenosis. Advanced disease can be accurately diagnosed, whereas early cancer should be differentiated from other neoplastic or inflammatory disorders by meticulous analysis of radiologic findings. The extent of GI involvement and multiplicity of the lesions can be assessed on barium studies. In the staging of GI neoplasms, barium studies are of little value. Skeletal survey by conventional radiographs and chest plain films can reveal distant metastases in a short time and with low cost, although they are not that sensitive to the detection of early or subtle lesions. The exact role of conventional radiology in the imaging workup of GI malignancies depends on local expertise and availability of other diagnostic techniques and modalities.

Small-bowel obstruction: optimizing radiologic investigation and nonsurgical management

Small-bowel obstruction is an old and common problem. Like most illnesses, its diagnosis and treatment continue to evolve. The radiologic approach to the investigation of small-bowel obstruction and the timing of surgical intervention have undergone considerable changes during the past decade. In this review, the authors analyze the recently described radiologic techniques used in the examination of patients with suspected mechanical small-bowel obstruction, revisit the controversy of the short versus long decompression tube, and provide insights on how to optimize the radiologic investigation and nonsurgical management of small-bowel obstruction.

Enteroclysis and spiral CT examination in diagnosis and evaluation of small bowel Crohn's disease

INTRODUCTION

During the last few decades introducing many of new radiologic methods, diagnostic conditions and facilities of Crohn's disease has became markedly improved. Appropriate using of these technics definitely modifies the management of patients with known or suspected Crohn's disease serving reliable information about extent, severity and possible complications of disease. Enteroclysis and Computed tomography are the two major and basic methods to disclose or confirme diagnosis of Crohn's disease, obtain appropriate inforination about disease either with mucosal, transmural or extraintestinal manifestation.

METHODS AND PATIENTS

We evaluated 281 patients who were referred in our institution under suspition of Crohn's disease. Enteroclysis and abdominal spiral CT in all cases were carried out usually within 1 week. The 172 patients underwent abdominal spiral CT as the primary examination to evaluate diagnostic value of spiral CT in this entity, while 109 patiens had enteroclysis followed by abdominal CT. In 11 cases we also perforined CT enteroclysis with administration of 0.5% methylcellulose solution thorough nasojejunal tube controlled by electric motor driven contrast pump. Results were compared with final clinical, pathological or surgical data were available.

RESULTS

From the 281 patients eventually 74 proved Crohn's disease; sensitivity and specificity of enteroclysis proved to be 96 and 98%, while spiral CT sensitivity and specificity was 94 and 95%, respectively. Enteroclysis was superior to the spiral CT in demonstration of early lesions and functional disorders, while spiral CT proved to be essential in evaluation of transmural and extraintestinal complications.

CONCLUSIONS

Regarding enteroclysis and spiral CT as complementary methods, they provide excellent results in diagnosis of Crohn's disease.

Balloon-occluded endoscopic retrograde ileography

For diagnostic ileography, the authors developed balloon-occluded endoscopic retrograde ileography and performed 77 studies in 36 consecutive patients with Crohn disease. Balloon-occluded endoscopic retrograde ileography proved to be useful in visualization of minute mucosal lesions such as aphthous ulcers and lymphoid hyperplasia in the distal ileum, and satisfactory ileographic images of Crohn disease were obtained in 54 (70%) studies.

Small bowel polyps in Peutz-Jeghers syndrome: management by combined push enteroscopy and intraoperative enteroscopy

BACKGROUND

Polyps occur throughout the GI tract in Peutz-Jeghers syndrome; the major problem in the management of the syndrome lies in the small bowel.

METHODS

From January 1979 to January 1998, seven patients with Peutz-Jeghers syndrome underwent surveillance. Between 1979 and 1992 they were managed with upper and lower endoscopy every 2 to 3 years and surgery when intestinal obstruction occurred. From 1993 they also underwent enteroclysis and, on the basis of radiologic findings, push enteroscopy and/or intraoperative enteroscopy. Push enteroscopy was then performed every 2 years in all patients.

RESULTS

During the first period, 5 of 7 patients underwent emergency small bowel resection (2 operated twice). The patients were divided into 2 groups based on enteroclysis findings; the first comprised 4 patients with multiple polyps throughout the small bowel, and the second included 3 patients with polyps only in the proximal small bowel. Three of the 4 patients with diffuse polyposis underwent intraoperative enteroscopy during which on average 16 polyps per patient were removed (range 10 to 25 polyps; mean diameter 16 mm, range 3 to 50 mm). The remaining patient with diffuse polyposis had a single 25 mm polyp in the terminal ileum removed by retrograde ileoscopy; the more proximal polyps were removed by push enteroscopy. The patients with diffuse polyposis remained asymptomatic during follow-up (mean 50 months, range 47 to 57 months) and also underwent periodic push enteroscopy (mean 2.25 enteroscopies per patient, range 2 to 3) at which a mean of 8.5 polyps per patient (range 4 to 13 polyps) were removed (mean diameter 7.2 mm, range 3 to 15 mm). The 3 patients of the second group underwent periodic push enteroscopy alone (mean 3 per patient) during which a mean of 11.7 polyps per patient were removed (range 7 to 15 polyps: mean diameter 10.9 mm, range 3 to 40 mm). Enteroclysis was not repeated in these patients, who remained asymptomatic during follow-up (mean 47 months, range 46 to 48 months).

CONCLUSIONS

More effective clearance of small bowel polyps via enteroscopy will help reduce the need for emergency surgery with extensive intestinal resection in patients with Peutz-Jeghers syndrome.

Intestinal obstruction

Intestinal obstruction, a disorder that afflicts both children and adults, is associated with significant morbidity. Early recognition and appropriate management can prevent life-threatening complications; however, considerable controversies exist regarding the ideal method of diagnosis and treatment. This article provides a comprehensive overview of risk factors for small and large bowel obstruction. The pathophysiologic process is related to the clinical findings. A summary of diagnostic methods with an evaluation of their relative merit is presented. Preventive, and medical, surgical, and palliative therapies are described, with an emphasis on the actions that an advanced practice nurse can implement.

The small bowel as a source of gastrointestinal blood loss

The small bowel is a rare but important source of blood loss from the gastrointestinal (GI) tract. In approximately 5% of all patients with GI bleeding, no cause for the bleeding is evident even after an extensive workup. This bleeding is often termed "gastrointestinal bleeding of obscure origin" or "obscure gastrointestinal bleed" (OGIB). Recent advancements in enteroscopy have contributed to a better understanding of the small bowel as a source of bleeding. On average, 27% of patients with OGIB have been shown to have lesions in the small bowel, with common findings including arteriovenous malformations (AVMs) and small bowel tumors. The trend in primary diagnostic workup for obscure GI bleeding or suspected small bowel lesions is shifting toward enteroscopic examination. Availability of an accessory channel now offers the clinician management options such as endoscopic injection therapy, electrocautery, and polypectomy. The "gold standard" for examination of the entire small bowel is intraoperative enteroscopy. A newer technique involving laparascopic assistance may lower the morbidity associated with this examination. Combined hormonal therapy may be an alternative treatment for patients with AVMs or an unknown cause of bleeding after enteroscopic examination.

Malabsorption syndromes

BACKGROUND/AIMS

Malabsorption syndromes commonly result from a pathological interference of the normal digestive process. There have been major advances in the last 4 years. The purpose of this review is to highlight in the form of a brief summary the most outstanding information available.

METHODS

The review was performed based on a medical literature search using MEDLINE (1993-1997), bibliographic reviews of book chapters and review articles. As a consequence of the extensive information incorporated in the period and the limited scope of this review, the review will focus in three aspects: (1) an overview on some clinical aspects of malabsorption; (2) diseases in which predominates the disturbed mucosal phase of the digestive process, and (3) providing information on diagnostic testing regarding malabsorption.

RESULTS

Major advances on celiac disease, Whipple's disease, giardiasis, tropical sprue, malabsorption of oligo- and disaccharides, vitamin B12 and bile salts are discussed. New aspects on diagnostic procedures for malabsorption are also presented.

CONCLUSION

Although major advances have given a great support to the investigation of malabsorption, yet the syndrome remains a major diagnostic dilemma. Based on the limited availability of most diagnostic tests, a simple and practical diagnostic algorithm is presented.