A combination of small bowel imaging methods: conventional enteroclysis with complementary magnetic resonance enteroclysis

Capsule endoscopy is useful diagnostic tool for diagnosing Meckel's diverticulum

OBJECTIVE

Meckel's diverticulum (MD) is the most common congenital anomaly of the gastrointestinal tract. Although a majority of patients remain asymptomatic, complications may occur in a subset of patients. MD is a rare cause of gastrointestinal bleeding (GIB) in adults. We aimed to clarify the possible role of capsule endoscopy (CE) in the identification of Meckel's diverticulum.

PATIENTS AND METHODS

From October 2004 to December 2010, 157 CEs were performed (83 male individuals, mean age 51±20 years; range 3-83 years) for obscure GIB. Before CE, all patients underwent nonconclusive upper and lower endoscopy at least two times and barium follow-through.

RESULTS

CE identified the source of bleeding in 70/157 patients (44.6%). MD was diagnosed in 13/70 (18.6%) patients (11 male individuals, mean age 35±20 years, range, 3-69 years) after CE. Nine patients presented with obscure overt and four with obscure occult bleeding. The mean duration of obscure GIB history was 13 months (range 1-72 months). The mean hemoglobin concentration at the time of the procedure was 115±12 g/l. The findings of MD on CE were double lumen sign (13/13), visible blood (7/13), and diaphragm sign (6/13). All patients were operated upon, and MD histologically verified in 11. In two patients CE was false-positive and in two patients, false-negative. Capsule endoscopy had a positive predictive value of 84.6% for the diagnosis of MD.

CONCLUSION

MD should be considered in the differential diagnosis of obscure GIB in adults. CE is an effective and promising modality for diagnosing MD in patients with obscure GIB.

Magnetic resonance enterography in Crohn's disease: a comparison with the findings at surgery

AIM

Magnetic resonance (MR) enterography is a radiation-free small bowel investigation which identifies luminal and extra-luminal pathology in patients with Crohn's disease. Most studies have validated MR against conventional radiology. We evaluated the results of MR enterography by comparison with findings at elective surgery for patients with Crohn's disease, including complex pathology.

METHOD

Between January 2007 and March 2012 the results of preoperative MR enterography for Crohn's disease in consecutive patients in one unit were compared with the detailed findings at surgery.

RESULTS

Fifty-one patients underwent 55 laparotomies during the study period. MR enterography identified the presence of Crohn's disease in the distal ileum in 33/34 patients, in the proximal ileum in 7/12 patients, in the jejunum in 7/8 patients, in the large bowel in 10/11 patients and in the duodenum in one of two patients. MR enterography identified ileo-enteric fistula in 10/12 patients, ileosigmoid fistula in all of seven patients and other fistulae in 10/11 patients. An abscess was identified on MR enterography in eight of nine patients. Within abnormal distal ileal segments, the mean contrast enhancement ratio of acute inflammation was 2.39 ± 0.59 compared with 1.82 ± 0.63 (P < 0.05) in segments with fibrosis only.

CONCLUSION

Magnetic resonance enterography identifies small bowel Crohn's disease with an accuracy similar to or better than those of previously published series. Fistulation, abscess formation and large bowel disease can be reliably identified and disease activity assessed. Normal, uninvolved small bowel length can also be measured. Discrete proximal small bowel lesions may not always be detected. In our practice, MR enterography has replaced conventional radiology in the assessment of symptomatic patients with Crohn's disease.

Assessment of dynamic contrast enhancement of the small bowel in active Crohn's disease using 3D MR enterography

PURPOSE

To retrospectively compare the dynamic contrast enhancement of the small bowel segments with and without active Crohn's disease at 3D MR enterography (MRE).

MATERIALS AND METHODS

Thirteen patients (five men, eight women; mean age 41.2 years; range 29-56) were imaged on a 1.5-T MR scanner (Sonata, Siemens Medical) with standard MR sequences after having ingested 1000 ml of a 3% mannitol solution. Subsequently, high resolution 3D gradient-echo (volumetric interpolated breath-hold examination=VIBE) data sets were obtained pre-contrast and 20-40s, 60-80s, and 120-140 s after i.v. Gd-DOTA administration (0.2 mmol/kg). Signal enhancement was measured on single slices both in normal and histologically confirmed (12/13) inflamed small bowel wall segments as well as in the aorta, the psoas muscle, and the background to calculate signal-to-noise (SNR) and contrast-to-noise ratios (CNR).

RESULTS

Small bowel wall enhancement was significantly higher (p<0.05) in inflamed compared to normal segments at 20-40s (SNR inflamed: 58.7+/-33.8 vs normal: 36.0+/-19.8; p=0.048; CNR inflamed: 34.8+/-23.4 vs normal: 16.3+/-11.2; p=0.017) and at 60-80s (SNR: 60.3+/-25.1 vs 41.9+/-20.0; p=0.049; CNR: 34.9+/-15.1 vs 19.3+/-13.2; p=0.01) after i.v. contrast administration, respectively. Even at 120-140 s CNR was still increased in inflamed segments (33.7+/-16.0 vs 18.1+/-13.2; p=0.04), while differences in SNR did not attain statistical significance (63.0+/-26.2 vs 45.3+/-23.3; p=0.15).

CONCLUSION

In active Crohn's disease, histologically confirmed inflamed small bowel wall segments demonstrate a significantly increased early uptake of gadolinium on 3D VIBE sequences compared to normal small bowel segments.

Radiological features of Meckel's diverticulum and its complications

Meckel's diverticulum is the most common congenital abnormality of the small bowel. The majority of patients with this anomaly will remain asymptomatic; however, several complications may occur, including obstruction, intussusception, perforation, diverticulitis, and gastrointestinal haemorrhage. These complications may produce a variety of different clinical features and radiological appearances. The purpose of this article is to review the potential imaging manifestations of Meckel's diverticulum and its complications and discuss the advantages and disadvantages of the imaging techniques available.

Is small-bowel radiography necessary before double-balloon endoscopy?

OBJECTIVE

Small-bowel radiography may be replaced by enteroscopy in the diagnosis of small-intestine lesions. We retrospectively elucidated the diagnostic yield of small-bowel radiography performed before double-balloon endoscopy.

MATERIALS AND METHODS

One hundred twenty-four patients who underwent double-balloon endoscopy during the period 2004-2006 were classified into those with abnormal radiographic findings (n = 45), normal radiographic findings (n = 31), and no small-bowl radiographs (n = 48). The classification was based on the use of small-bowel radiography and the diagnosis before double-balloon endoscopy. The indications for, approaches to, and diagnostic yields of double-balloon endoscopy were compared for the three groups. The diagnostic yield of small-bowel radiography was considered positive when any sign of pathologic change in the small bowel was identified. The diagnostic yield of double-balloon endoscopy was considered positive when endoscopic or biopsy findings explained the clinical manifestations.

RESULTS

The group with abnormal findings on small-bowel radiography was younger (15-86 years) and less frequently had obscure bleeding (8.9%) than the group with normal findings on small-bowel radiography (age, 17-84 years; frequency of obscure bleeding, 45.2%) (p = 0.01) or the group without small-bowel radiographs (age, 15-91 years; frequency of obscure bleeding, 64.6%) (p < 0.0001). The positive diagnostic yield of double-balloon endoscopy was highest in the group with abnormal findings on small-bowel radiography (71.1%), followed by the group with no small-bowel radiographs (45.8%) and the group with normal findings on small-bowel radiography (35.5%) (p = 0.0002). Among patients who did undergo small-bowl radiography, the accuracy of the technique was 68.4%, the positive predictive value was 71.1%, and the negative predictive value was 64.5%. The positive diagnostic yields of small-bowel radiography and double-balloon endoscopy were not statistically different (59.2% for small-bowel radiography, 56.6% for double-balloon endoscopy; p > 0.1).

CONCLUSION

The diagnostic accuracy of double-balloon endoscopy seems to improve if the procedure is preceded by small-bowel radiography.

Technology Insight: new techniques for imaging the gut in patients with IBD

Advances in techniques for imaging the gut continue to drive the rapid development of modalities for diagnosing and assessing the activity of IBD. Abdominal ultrasound and magnetic resonance enterography have shown great potential for the diagnosis of IBD and assessment of its distribution, with the benefit of avoiding radiation exposure and serving as a safe option for pregnant patients. CT enterography or CT enteroclysis, with neutral or negative contrast, seems to be a sensitive and specific modality for detecting disease in the small bowel. The role of CT or magnetic resonance colonography in patients with IBD remains uncertain and these modalities are now best reserved for patients who decline or cannot undergo standard endoscopic evaluations. Capsule endoscopy might be the most sensitive modality for the detection of mucosal small bowel disease, but its specificity remains in question. Double-balloon endoscopy is an exciting new tool that has the distinct advantage of enabling biopsy or treatment of lesions detected during the procedure. All these techniques are at the forefront of the rapidly evolving field of imaging the gut in patients with IBD.

Current and future diagnostic approaches: from serologies to imaging

Advances in serologic markers and imaging modalities continue to revolutionize diagnostic approaches to inflammatory bowel disease (IBD). Autoimmune and antimicrobial antibodies demonstrate diagnostic value in those patients with a moderate pretest probability of disease. Emerging data also support the use of antimicrobial antibody levels as a predictive tool for small bowel complications and the need for future surgery. In addition to being a prognostic marker in patients with acute severe colitis, serum C-reactive protein has been shown to correlate with clinical, endoscopic, and radiologic measures of disease activity. Capsule endoscopy and double-balloon endoscopy allow for visualization of the entire small bowel, and double-balloon endoscopy also has the capability to treat lesions. CT enterography is beginning to replace small bowel follow-through because of its high sensitivity and specificity for disease of the small intestine. Both CT and magnetic resonance enterography detect luminal and extraluminal abnormalities, with MRI serving as a safe imaging option in cases of pregnancy and renal insufficiency. These newer modalities add to the armamentarium clinicians can use for evaluation of IBD.