Small bowel

MR imaging, using modern equipment and a rigorous technical approach, can offer detailed morphologic information and functional data on the small bowel. The optimal study technique is debatable, although the oral administration of contrast material as a first-line approach is less expensive, faster, easier to perform, and better tolerated by patients. MR enteroclysis might be reserved for selected cases as a second-line study. The major clinical indication is the evaluation of patients who have suspected or known Crohn's disease. The absence of ionizing radiation, considering the young age of most of the patients and the frequency of the examinations, is an important advantage over other techniques (radiograph and CT enteroclysis).     

Small bowel obstruction

Gallstone ileus is a rare complication of cholelithiasis, but an established cause of mechanical small bowel obstruction in elderly patients. It is associated with high morbidity and mortality as most patients are elderly with multiple comorbidities. Surgery of choice is enterolithotomy.     

Small bowel tuberculosis

We describe the radiologic appearances of small bowel tuberculosis as shown by enteroclysis. A total of 265 patients with proven small bowel tuberculosis seen over a period of more than one decade was evaluated. All patients had positive radiologic findings as shown on enteroclysis examination. Of the 265 patients with small bowel tuberculosis, 174 had isolated small bowel involvement with a normal ileocecal region, whereas 91 had associated noncontiguous involvement of the ileocecal region. The most common radiologic finding was the presence of strictures, noted in 62.7% of cases. Most strictures were short, concentric, and smooth in outline. These strictures were solitary or multiple and located mainly in the jejunum. Other radiologic findings were adhesions (21.8%), ulcerations (9.1%), and diffuse thickening of folds (6.4%). Complications noted were in the form of enteroliths, perforations, and fistulae. The radiographic findings of small bowel tuberculosis, although nonspecific, may indicate tuberculosis in a high-risk population.     

Small bowel volvulus

Two cases of small bowel volvulus with mild clinical symptoms in which upper gastrointestinal series, computed tomography, and magnetic resonance imaging were performed are reported. Angiography was also performed in one case. Neither patient received laparotomy and the diagnosis was based on imaging findings.     

Small bowel endoscopy

Video capsule endoscopy continues to be the major focus in papers dealing with diagnostic small-bowel endoscopy. Although capsule endoscopy is used for a variety of indications, its major field of application is still obscure bleeding from the small intestine, where it can be regarded as a first-line test. There is increasing evidence that capsule endoscopy for suspected Crohn's disease may be diagnostic in individual cases after inconclusive conventional tests. Push enteroscopy is the clinical reality for biopsy and treatment in the proximal small bowel, whereas intraoperative enteroscopy is used for distal or diffuse small-intestinal disorders. Further reports on double-balloon enteroscopy suggest that this method may be able to replace at least intraoperative enteroscopy in many circumstances. The availability of specific antibody tests for celiac disease is leading to recurrent interest in endoscopy and histology, showing that villous atrophy and lymphocytic infiltrates are typical, but not specific, findings.     

Small bowel transplantation

Small bowel transplantation has become the treatment of choice for patients with chronic gut failure whose illness cannot be maintained on home parenteral nutrition. Outcomes have improved as a result of refinements in patient selection, surgical techniques, and the prevention, diagnosis, and treatment of graft rejection. Early listing is important because of the shortage of organ donors. Rejection rates are still 50% or more, despite the use of potent immune suppression. Sepsis rates are also higher for patients who have had small bowel transplantation than for those who have received other organs because of bacterial translocation from the gut secondary to preservation injury and graft rejection. Graft and patient survival rates after small bowel transplantation are comparable to rates after lung transplantation. Successful transplant recipients resume unrestricted oral diets.     

Small bowel transplantation

Early attempts of small bowel transplantation (SBTx) were unsuccessful as a result of uncontrolled rejection and infection. Introduction of tacrolimus in the early 1990s improved the outcome, but results were not satisfactory comparing those after the other organ transplants. Recently, improved long-term graft survivals were reported from several centers. According to Intestine Transplant Registry (ITR), a multivariate analysis of cases within the last 5 years revealed that transplantation of patients waiting at home, recipient age, antibody induced immune suppression, and center experience with at least 10 cases were associated with improved patients survival. One-year graft survival rate of 90% were achieved in patients who were treated with antithymocyte globulin and maintained on tacrolimus.     

Small bowel tumors

WCE is a noninvasive diagnostic technique that visualizes the entire small intestine and identifies lesions in parts of the small bowel not reached by traditional endoscopy. Although further studies are needed to define the exact role of WCE for diagnosing and managing small bowel tumors, its sensitivity has been shown to be superior to PE and small bowel follow-through in regard to diagnosing patients who have obscure GI bleeding, the most common indication for capsule endoscopy in the authors' series of patients with documented small bowel tumors. As more material is published, capsule endoscopy likely will be confirmed to be the diagnostic procedure of choice in patients with suspected small bowel tumors.