Crohn disease of the small intestine: accuracy and relevance of enteroclysis

Duodenal Crohn's disease: Case report and systematic review

BACKGROUND

Inflammatory bowel disease, including ulcerative colitis, microscopic colitis, and Crohn's disease (CD), has a global impact. This review focuses on duodenal CD (DCD), a rare subtype affecting the duodenum. DCD's rarity and asymptomatic nature create diagnostic challenges, impacting prognosis and patient well-being. Delayed diagnosis can worsen DCD outcomes.

AIM

To report a rare case of DCD and to discuss the diagnostic challenges and its implications on prognosis.

METHODS

A systematic literature search, following the PRISMA statement, was conducted. Relevant studies were identified and analysed using specific Medical Subject Terms (MeSH) from PubMed/MEDLINE, American Journal of Gastroenterology, and the University of South Wales database. Data collection included information from radiology scans, endoscopy procedures, biopsies, and histopathology results.

RESULTS

The review considered 8 case reports and 1 observational study, involving 44 participants diagnosed with DCD, some of whom developed complications due to delayed diagnosis. Various diagnostic methods were employed, as there is no gold standard workup for DCD. Radiology scans [magnetic resonance imaging (MRI), computed tomography (CT), and upper gastrointestinal X-ray], endoscopy procedures (colonoscopy and esophagogastroduodenoscopy), biopsies, and clinical suspicions were utilized.

CONCLUSION

This review discusses DCD diagnosis challenges and the roles of CT, MRI, and fluoroscopy. It notes their limitations and compares findings with endoscopy and histopathology studies. Further research is needed to improve diagnosis, emphasizing scan interpretation, endoscopy procedures, and biopsies, especially in high-risk patients during routine endoscopy.

Crohn's disease at radiological imaging: focus on techniques and intestinal tract

Over recent years, inflammatory bowel diseases have become an issue of increased attention in daily clinical practice, due to both a rising incidence and improved imaging capability in detection. In particular, the diagnosis of Crohn's disease is based on clinical picture, laboratory tests and colonoscopy with biopsy. However, colonoscopic evaluation is limited to the mucosal layer. Thus, imaging modalities play a pivotal role in enriching the clinical picture, delivering information on intestinal and extraintestinal involvement. All the imaging modalities can be employed in evaluation of Crohn's disease patients, each of them with specific strengths as well as limitations. In this wide selection, the choice of a proper diagnostic framework can be challenging for the clinician. Therefore, the aim of this work is to offer an overview of the different imaging techniques, with brief technical details and diagnostic potential related to each intestinal tract.

Ingestible Contrast Agents for Gastrointestinal Imaging

Gastrointestinal (GI) ailments cover a wide variety of diseases involving the esophagus, stomach, small intestine, large intestine, and rectum. They bring about many inconveniences in daily life in chronic diseases and can even be life threatening in acute cases. Rapid and safe detection approaches are essential for early diagnosis and timely management. Contrast agents for GI imaging can enhance contrast to distinguish abnormal lesions from normal structures. Computed tomography and magnetic resonance imaging are two important diagnostic tools for the evaluation of GI conditions. This review mainly involves several common GI diseases, including inflammatory diseases, intestinal tumors, diarrhea, constipation, and gastroesophageal reflux diseases. Selected contrast agents, such as barium sulfate, iodine-based agents, gadolinium-based agents, and others, are summarized. Going forward, continued endeavors are being made to develop more emerging contrast agents for other imaging modalities.

Magnetic resonance enterography predicts the prognosis of Crohn's disease

Background/Aims

Magnetic resonance enterography (MRE) has emerged as an important tool in the diagnosis and follow-up of Crohn's disease (CD). The aim of this study was to evaluate whether MRE findings could predict the prognosis of CD.

Methods

In this retrospective study, a total of 173 patients with clinical remission of CD (n=61) or active CD (n=112) were identified. The outcomes of clinical relapse, admission, surgery, and need for other medications according to the MRE findings were evaluated.

Results

The presence of active inflammation on MRE was observed in 93 (83%) patients with clinically active CD and in 44 (72.1%) patients with clinical remission of CD, without a statistically significant difference (P=0.091). In multivariate analysis, active inflammation on MRE increased the risk for clinical relapse (hazard ratio [HR], 6.985; 95% confidence interval [CI], 1.024–47.649) in patients with clinical remission of CD. In patients with clinically active CD, active inflammation on MRE increased the risk for CD-related hospitalization (HR, 2.970; 95% CI, 1.006–8.772).

Conclusions

The presence of active inflammation on MRE was significantly associated with poor prognosis both in patients with clinical remission of CD and in those with active CD.

Imaging in the evaluation of the young patient with inflammatory bowel disease: what the gastroenterologist needs to know

Imaging plays a pivotal role in the diagnosis and management of children and young adults with inflammatory bowel disease. The clinician is presented with numerous imaging options, and it can be challenging to decide which test is the best option. In this article we review the present imaging techniques available in the evaluation of inflammatory bowel disease, with emphasis on the advantages, disadvantages, and radiation burden of each test. Finally, we highlight a few common clinical scenarios and propose an imaging algorithm to approach these diagnostic challenges.

Diagnostic imaging in Crohn's disease: what is the new gold standard?

Historically Barium and isotope studies been used for imaging of inflammatory bowel disease (IBD) but carry risk of radiation exposure. Use of Barium is declining resulting in fewer radiologists that have the necessary expertise. Isotopes studies lack anatomical definition but 18F - fludeoxyglucose (FDG) positron emission tomography (PET) shows promise in accurate assessment of disease compared to endoscopy. Computerised tomography (CT) is particularly useful in assessment of complications of Crohn's disease (CD) but radiation exposure is high. CT enterography (CTE) has improved visualisation of small bowel mucosal disease and allows assessment of disease activity. Ultrasound is increasingly used for preliminary assessment of patients with potential IBD. Although widely available and economically attractive, the expertise required is not widespread. Finally magnetic resonance imaging (MRI) is proving to be the most accurate tool for assessment of disease extent and distribution. MRI of the pelvis has superseded other techniques in assessment of peri-anal fistulation.

Intraoperative enteroscopy detects more lesions but is not predictive of postoperative recurrence in Crohn’s disease

BACKGROUND

The aim of this investigation was to elucidate the clinical value of intraoperative enteroscopy (IOE) for Crohn's disease, and to determine the value of IOE in predicting recurrent disease.

METHODS

In this study 27 patients requiring surgery were examined by both preoperative radiography and IOE. The findings obtained by these procedures in the remnant small intestine were compared. In 19 patients, the clinical course and colonoscopic or radiographic findings after surgery were analyzed.

RESULTS

Intestinal lesions were identified in 23 patients by IOE, and in 19 patients by radiography. Longitudinal ulcers were equivalently detected by IOE (63%) and radiography (56%), whereas small ulcers and inflammatory polyps were less frequently detected by radiography than by IOE (37% vs 74% and 19% vs 33%, respectively). Neither the presence nor the distribution of IOE findings was related to postoperative recurrence.

CONCLUSIONS

Whereas IOE demonstrates small intestinal lesions in detail, the procedure alone cannot predict postoperative recurrence in Crohn's disease.

Imaging techniques for assessment of inflammatory bowel disease: joint ECCO and ESGAR evidence-based consensus guidelines

The management of patients with IBD requires evaluation with objective tools, both at the time of diagnosis and throughout the course of the disease, to determine the location, extension, activity and severity of inflammatory lesions, as well as, the potential existence of complications. Whereas endoscopy is a well-established and uniformly performed diagnostic examination, the implementation of radiologic techniques for assessment of IBD is still heterogeneous; variations in technical aspects and the degrees of experience and preferences exist across countries in Europe. ECCO and ESGAR scientific societies jointly elaborated a consensus to establish standards for imaging in IBD using magnetic resonance imaging, computed tomography, ultrasonography, and including also other radiologic procedures such as conventional radiology or nuclear medicine examinations for different clinical situations that include general principles, upper GI tract, colon and rectum, perineum, liver and biliary tract, emergency situation, and the postoperative setting. The statements and general recommendations of this consensus are based on the highest level of evidence available, but significant gaps remain in certain areas such as the comparison of diagnostic accuracy between different techniques, the value for therapeutic monitoring, and the prognostic implications of particular findings.

Imaging of pediatric patients with inflammatory bowel disease

OBJECTIVE

The goal of this review is to examine the current imaging literature and develop basic imaging guidelines for evaluation of children with inflammatory bowel disease (IBD). The three following typical clinical scenarios in the imaging evaluation of IBD are considered: patient with an initial diagnosis of suspected IBD, the goals being to determine disease extent and severity and to differentiate Crohn disease from ulcerative colitis; patient with known IBD presenting with new acute symptoms (fever, peritonitis, leukocytosis) requiring urgent evaluation; and patient with known IBD presenting with nonacute symptomatic recurrence (abdominal pain, diarrhea), the goals being to assess the efficacy of the current treatment and to evaluate the possible need for additional medical or surgical intervention.

CONCLUSION

Imaging of pediatric patients with IBD must balance considerations of diagnostic accuracy against concerns about patient exposure to ionizing radiation and tolerance of the imaging technique. The imaging modality chosen depends on the clinical presentation and expected pathologic finding.

Small bowel imaging in Crohn's disease

Imaging of Crohn's disease of the small bowel is gradually moving away from barium fluoroscopy and towards cross-sectional modalities. This review explores the strengths and limitations of various techniques, and focuses on several current questions in small bowel imaging, such as the comparison between oral ingestion or nasojejunal intubation and enteroclysis for introduction of contrast, the use of computerised tomography (CT) versus magnetic resonance (MR) and the likely changes over the next decade.

Small intestine contrast ultrasonography (SICUS) for the detection of small bowel complications in crohn's disease: a prospective comparative study versus intraoperative findings

BACKGROUND

In Crohn's disease (CD) patients, small intestine contrast ultrasonography (SICUS) accurately assesses small bowel lesions. Its diagnostic role is not known in the assessment of intraabdominal CD complications. The aim was to assess the value of SICUS to detect intestinal complications in patients with CD.

METHODS

Forty-nine CD patients (21 female, mean age 37.7 years; range 12-78 years) underwent resective bowel surgery and were included in this study. The accuracy of SICUS to preoperatively detect number, site, and length of strictures, fistulas, and abscesses was compared with surgical and pathological findings by kappa statistics.

RESULTS

SICUS identified at least one stricture in 39/40 and excluded it in 9/9 (97.5% sensitivity, 100% specificity, k = 0.93); two or more strictures in 9/12 (75% sensitivity, 100% specificity, k = 0.78). The agreement by k-statistics between SICUS and surgery in identifying proximal and distal small intestine site of stricture was 1 and 0.92, respectively. The extension of strictures was 6.8 ± 5.4 cm at surgery, 6.6 ± 5.4 cm at SICUS (NS). Fistulas were correctly identified in 27/28 patients and excluded in 19/21 patients (96% sensitivity, 90.5% specificity, k = 0.88). Intraabdominal abscesses were correctly detected in 10/10 patients and excluded in 37/39 patients (100% sensitivity, 95% specificity, k = 0.89).

CONCLUSIONS

SICUS is an accurate method for the detection of small intestinal complications in CD. Noninvasive SICUS is valuable as a primary investigative method for evaluating and planning proper treatment in patients with severe CD of the small bowel.

Recent advances in intestinal imaging

In recent years, advances in scanner technology and competition from other specialties have produced rapid changes in the way the intestines are imaged. MRI and CT scan along with the traditional enteroclysis examination have emerged at the forefront of intestinal imaging. Functional modalities such as diffusion and perfusion imaging are also changing the way tumors and inflammatory bowel diseases are evaluated. CT colonography is now a valid alterative to optical colonoscopy. Contrast-enhanced USG is being used for the assessment of inflammation and post-treatment changes. In this review, recent advances in intestinal imaging are described.

Diffusion-weighted MRI: role in detecting abdominopelvic internal fistulas and sinus tracts

PURPOSE

To retrospectively determine the incremental value of diffusion-weighted MR-imaging (DW-MRI) to T2-weighted (T2w) images in diagnosis of internal fistulas (IFs) and sinus tracts (STs).

MATERIALS AND METHODS

Fourteen patients with 25 IFs and STs arising from the small bowel (20), colon (4) and biliary tract (1) were included. Two independent observers reviewed T2w images, T2w+DW-MRI images and T2w+contrast enhanced T1-weighted (CE T1w) images at three sessions to detect IF/ST based on a confidence scale of five. Sensitivity and confidence score of each session was compared.

RESULTS

10/25 (40%) and 9/25 (36%) IFs and STs were detected on T2w images by observer 1 and 2, respectively. Both observers detected 19/25 (76%) and 24/25(96%) IFs and STs on T2w+DW-MRI and T2w+CE T1w images, respectively. Detection rate and confidence score improved significantly by combining T2w images with DW-MRI or CE T1w images (reader 1 + 2: P ≤ 0.01). There was no significant difference between the IF/ST detection rate of T2w+DW-MRI and T2w+CE T1 image combinations. Confidence scores with T2w+CE T1w images were significantly greater than DW-MRI+T2w images (reader 1:P = 0.01; reader 2: P = 0.03).

CONCLUSION

DW-MRI showed additional value to T2w imaging for diagnosis of IF and ST. DW-MRI can be a useful adjunct, especially for patients with renal failure.

Prospective comparison of computed tomography enterography and magnetic resonance enterography for assessment of disease activity and complications in ileocolonic Crohn's disease

BACKGROUND

Studies comparing magnetic resonance enterography (MRE) and computerized tomography enterography (CTE) for Crohn's disease (CD) are scarce.

METHODS

The aim of this study was to prospectively compare the sensitivity, specificity, and accuracy of abdominal MRE and CTE to assess disease activity and complications (fistulas, strictures) in ileocolonic CD. A total of 44 patients (23 male; 21 female; mean age 44) with ileocolonic CD underwent both MR and CT in a short time interval (mean 5 days). A 16-slice CT with intravenous contrast and an MRI with oral and paramagnetic intravenous contrast were performed. Ileocolonoscopy was used as the reference standard. Sensitivity values of CT and MR for detection of extraenteric signs of disease were compared with the McNemar test, with results of imaging studies, surgery, and physical examination as reference standards.

RESULTS

No significant differences in sensitivity, specificity, and accuracy were observed between MRE and CTE regarding the following parameters at the patient level: localization of CD (P = 1.0), bowel wall thickening (P = 1.0), bowel wall enhancement (P = 1.0), enteroenteric fistulas (P = 0.08), detection of abdominal nodes (P = 1.0), and perivisceral fat enhancement (P = 0.31). MR was significantly superior compared to CT in detecting strictures (P = 0.04). Per segment analysis showed that MRE was significantly superior to CTE in detecting ileal wall enhancement (P = 0.02).

CONCLUSIONS

MR and CT are equally accurate to assess disease activity and bowel damage in CD. MR may be superior to CT in detecting intestinal strictures and ileal wall enhancement. MR may represent an alternative technique to CT in assessing ileocolonic CD.

The role of nasoenteric intubation in the MR study of patients with Crohn's disease: our experience and literature review

PURPOSE

The aim of this study was to compare magnetic resonance (MR) enteroclysis with MR enterography to verify whether nasoenteric intubation in patients affected by Crohn's disease can provide supplementary information to that afforded by MR study of the small bowel.

MATERIALS AND METHODS

In a 12-month period, 40 patients (28 women and 12 men, mean age 35 years) affected by Crohn's disease underwent MR imaging. Distension of the small-bowel loops was obtained by administering polyethylene glycol: 15 patients were given the mixture by mouth (MR enterography), whereas the remaining 25 received it via nasoenteric intubation (MR enteroclysis). Our study protocol included morphological sequences taken before and after intravenous injection of contrast medium and real-time functional sequences. Accuracy criteria for the execution of the examinations were designed according to 11 bands.

RESULTS

Complete distension of the small-bowel loops was obtained in the 25 patients who underwent MR enteroclysis, with the additional advantage of a suitable assessment of those segments involved in the pathological process. This was not the case for the 15 patients who underwent MR enterography, because both the jejunum and the small-bowel loops appeared partially collapsed.

CONCLUSIONS

MR enteroclysis is the most effective technique for studying the small bowel in Crohn's disease, as it not only provides a suitable morphological assessment but also supplies functional information.

CT enterography and fistulizing Crohn's disease: clinical benefit and radiographic findings

BACKGROUND

To estimate the clinical benefit of CT enterography (CTE) in patients with fistulizing Crohn's disease and describe the appearance of fistulas at CTE.

METHODS

Crohn's patients who had undergone CTE, which diagnosed an abscess or fistula, were identified. A gastroenterologist reviewed clinical notes prior to and following CTE to assess the pre-CTE clinical suspicion for fistula/abscess, and post-CTE alteration in patient management. A radiologist reassessed all fistula-positive cases, which were confirmed by a non-CT reference standard, to describe their radiologic appearance.

RESULTS

Fifty-six patients had CT exams identifying 19 abscesses and 56 fistulas. There was no or remote suspicion of fistula or abscess at pre-imaging clinical assessment in 50% of patients. Thirty-four patients (61%) required a change in or initiation of medical therapy and another 10 (18%) underwent an interventional procedure based on CT enterography findings. Among 37 fistulas with reference standard confirmation, 30 (81%) were extraenteric tracts, and 32 (86%) were hyperenhancing compared to adjacent bowel loops. Most fistulas (68%) contained no internal air or fluid.

CONCLUSION

CTE detects clinically occult fistulas and abscesses, resulting in changes in medical management and radiologic or surgical intervention. Most fistulas appear as hyperenhancing, extraenteric tracts, usually without internal air or fluid.

Enteroscopy and its relationship to radiological small bowel imaging

The field of radiological small bowel imaging is changing rapidly, as is small bowel enteroscopy. New techniques allow the depiction of intraluminal, mural, and extraintestinal features of various small bowel disorders, such as Crohn disease, small bowel polyposis syndromes, small intestinal malignancies, and celiac disease. For patients requiring repeated small bowel imaging, modalities that do not use ionizing radiation, such as ultrasound or magnetic resonance imaging, should be considered.

Free-breathing diffusion-weighted imaging for the assessment of inflammatory activity in Crohn's disease

PURPOSE

To investigate the application of free-breathing diffusion-weighted MR imaging (DWI) to the assessment of disease activity in Crohn's disease.

MATERIALS AND METHODS

Thirty-one patients with Crohn's disease were investigated using free-breathing DWI without special patient preparation or IV or intraluminal contrast agent. The bowel was divided into seven segments, and disease activity was assessed visually on DWI. For quantitative analysis, the apparent diffusion coefficient (ADC) was measured in each segment. The findings of a conventional barium study or surgery were regarded as the gold standard for evaluating the diagnostic ability of DWI to assess disease activity.

RESULTS

Upon visual assessment, the sensitivity, specificity, and accuracy for the detection of disease-active segments were 86.0, 81.4, and 82.4%, respectively. In the quantitative assessment, the ADC value in the disease-active area was lower than that in disease-inactive area in small and large bowels (1.61 +/- 0.44 x 10(-3) mm(2)/s versus 2.56 +/- 0.51 x 10(-3) mm(2)/s in small bowel and 1.52 +/- 0.43 x 10(-3) mm(2)/s versus 2.31 +/- 0.59 x 10(-3) mm(2)/s in large bowel, respectively, P<0.001).

CONCLUSION

Free-breathing DWI is useful in the assessment of Crohn's disease. The accuracy of DWI is high in evaluating disease activity, especially in the small bowel, and the ADC may facilitate quantitative analysis of disease activity.

Crohn disease of the small bowel: comparison of CT enterography, MR enterography, and small-bowel follow-through as diagnostic techniques

PURPOSE

To prospectively compare the accuracy of computed tomographic (CT) and magnetic resonance (MR) enterography and small-bowel follow-through (SBFT) examination for detection of active small-bowel inflammation and extraenteric complications in patients with Crohn disease (CD).

MATERIALS AND METHODS

The institutional review board approved the study protocol; informed consent was obtained from all participants. Thirty-one consecutive patients who had CD or who were suspected of having CD underwent CT and MR enterography, SBFT, and ileocolonoscopy. Two independent readers reviewed CT and MR enterographic and SBFT images for presence of active terminal ileitis and extraenteric complications. Accuracy values of CT and MR enterography and SBFT for identification of active terminal ileitis were evaluated with the receiver operating characteristic method, with ileocolonoscopic findings as the reference standard. Sensitivity values of CT and MR enterography and SBFT for detection of extraenteric complications were compared by using the McNemar test, with results of imaging studies, surgery, and physical examination as reference standards.

RESULTS

The study population included 30 patients (17 men, 13 women; mean age, 29.0 years) with CD. Differences in areas under the receiver operating characteristic curves for CT enterography (0.900 and 0.894), MR enterography (0.933 and 0.950), and SBFT (0.883 and 0.928) for readers 1 and 2, respectively, in the detection of active terminal ileitis were not significant (P > .017). Sensitivity values for detection of extraenteric complications were significantly higher for CT and MR enterography (100% for both) than they were for SBFT (32% for reader 1 and 37% for reader 2) (P < .001).

CONCLUSION

Because MR enterography has a diagnostic effectiveness comparable to that of CT enterography, this technique has potential to be used as a radiation-free alternative for evaluation of patients with CD.

Assessment of Crohn's disease activity in the small bowel with MR-enteroclysis: clinico-radiological correlations

BACKGROUND

The aim of our study was to evaluate the accuracy of magnetic resonance imaging (MRI) in evaluating Crohn's disease (CD) activity compared to clinical/laboratory data.

METHODS

Ninety-three consecutive patients with CD were prospectively studied by MR imaging, before and after Gadolinium chelates administration, with use of a biphasic endoluminal contrast agent. MR image analysis included: number of lesions, presence/absence of bowel stenosis, upstream bowel dilation, wall thickness, presence of enhancement, enhancement pattern, presence/absence of comb sign, lymph nodes, and perianal fistulas/abscesses. Clinical evaluation was performed by means of Harvey & Bradshaw Index. Acute-phase reactants were considered standard of reference to monitor biological activity (BA). MR imaging findings were compared with clinical and laboratory data.

RESULTS

MR image analysis detected: In 96 exams multiple lesions in 16, 1 in 50; no lesions in 30; stenosis in 52; dilatation in 28; wall thickening in 59; significant enhancement in 57; layered pattern in 50; comb sign in 37; enlarged lymph nodes in 16; fibro-fatty proliferation in 40; fistulas in 9.

CONCLUSIONS

MRI is able to depict morphological changes and is helpful in assessing Crohn's inflammatory disease.

Role of MRI in Crohn's disease

The traditional imaging of Crohn's disease has relied on barium and computed tomography (CT) examinations. In recent years magnetic resonance imaging (MRI) has emerged as an imaging method that can be used in the diagnosis and assessment of Crohn's disease. The advantages of MRI include lack of ionizing radiation and its superior tissue contrast resolution. The clinical progression of Crohn's disease can be variable, and MRI can be used to assess inflammatory status, disease progression, and complications of Crohn's disease. MRI of the small bowel is an evolving technique and it has the potential to become the preferred technique for imaging of small bowel Crohn's disease in the future.

Detection of inflammatory bowel disease: diagnostic performance of cross-sectional imaging modalities

Different cross-sectional imaging techniques can be used as a diagnostic tool for the evaluation of inflammatory bowel disease (IBD). In this report the diagnostic performances of ultrasonography, magnetic resonance imaging and computed tomography in the detection of IBD and the evaluation of known IBD are described, together with a short update on patient preparation and imaging technique of the respective modalities discussed.

MRI of the small bowel: can sufficient bowel distension be achieved with small volumes of oral contrast?

Sufficient luminal distension is mandatory for small bowel imaging. However, patients often are unable to ingest volumes of currently applied oral contrast compounds. The aim of this study was to evaluate if administration of low doses of an oral contrast agent with high-osmolarity leads to sufficient and diagnostic bowel distension. Six healthy volunteers ingested at different occasions 150, 300 and 450 ml of a commercially available oral contrast agent (Banana Smoothie Readi-Cat, E-Z-EM; 194 mOsmol/l). Two-dimensional TrueFISP data sets were acquired in 5-min intervals up to 45 min after contrast ingestion. Small bowel distension was quantified using a visual five-grade ranking (5 = very good distension, 1 = collapsed bowel). Results were statistically compared using a Wilcoxon-Rank test. Ingestion of 450 ml and 300 ml resulted in a significantly better distension than 150 ml. The all-over average distension value for 450 ml amounted to 3.4 (300 ml: 3.0, 150 ml: 2.3) and diagnostic bowel distension could be found throughout the small intestine. Even 45 min after ingestion of 450 ml the jejunum and ileum could be reliably analyzed. Small bowel imaging with low doses of contrast leads to diagnostic distension values in healthy subjects when a high-osmolarity substance is applied. These findings may help to further refine small bowel MRI techniques, but need to be confirmed in patients with small bowel disorders.

Bowel ultrasound in Crohn's disease: surgical perspective

BACKGROUND

Bowel ultrasound has been proven to be a useful tool in the management of Crohn's disease, particularly in the assessment of intra-abdominal complications, most of which require surgery.

MATERIALS AND METHODS

The National Library of Medicine has been searched for articles on the use of bowel ultrasound in Crohn's disease focusing on aspects of interest to the surgeon.

RESULTS AND CONCLUSIONS

Several studies have demonstrated that bowel ultrasound may be useful to reduce the risk of unnecessary laparotomy in patients presenting acute abdomen with suspected chronic inflammatory bowel disease. Bowel ultrasound has been proven to be of value in the follow-up of Crohn's disease patients since allowing early diagnosis of intra-abdominal complications and, therefore, optimising the diagnostic and surgical approach. At followup, bowel ultrasound may accurately diagnose early postoperative complications and long-term disease recurrence. In patients submitted to conservative surgery, ultrasonography reveals changes in diseased bowel walls that may be predictive of recurrence of the disease, and hence determinant in the choice of medical treatment.

CT enterography for Crohn's disease: accurate preoperative diagnostic imaging

PURPOSE

CT enterography (CTE) is a technique that provides detailed images of the small bowel by using a low Hounsfield unit oral contrast media. This study was designed to correlate CTE findings with operative findings in patients with Crohn's disease.

METHODS

We performed a retrospective study of all patients with Crohn's disease of the small bowel or colon, who had CTE and subsequent small bowel or colon surgery within three months after the CT examination. CTE findings of stricture, fistula, inflammatory mass, abscess, and combinations of these abnormalities were compared with operative findings. Specialist radiologists and fellowship-trained colorectal surgeons participated in the study. The Fisher's exact test or chi-squared tests were used with respect to categorical data, and the Wilcoxon's rank-sum test was used for quantitative data.

RESULTS

In 36 patients, the presence or absence of stricture, fistula, abscess, or inflammatory mass was correctly determined by CTE in 100, 94, 100, and 97 percent, respectively. The accuracy for stricture or fistula number was 83 and 86 percent, respectively. There were nine patients with multiple disease phenotypes identified on CTE of which eight were confirmed at surgery. CTE overestimated or underestimated the extent of disease in 11 patients (31 percent).

CONCLUSIONS

CTE is an accurate preoperative diagnostic imaging study for small-bowel Crohn's disease. The ability of this imaging study to detect both luminal and extraluminal pathology is a distinct advantage of CTE compared with small-bowel contrast studies.

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.

Forty-slice MDCT enteroclysis: evaluation after oral administration of isotonic solution in Crohn's disease

OBJECTIVE

The aim of this study was to evaluate the accuracy of multidetector computed tomography (MDCT) enteroclysis after oral hyperhydration with isotonic solution in detecting bowel wall alterations in patients with Crohn's disease.

MATERIALS AND METHODS

Twenty-eight patients with a diagnosis of Crohn's disease established by ileocolonoscopy and histology were enrolled in the study; 15 patients with negative ileocolonoscopy served as controls. In all cases, MDCT enteroclysis was performed after oral administration of 2,000 ml of isotonic solution and intravenous administration of N-butylscopolamine. Axial, isotropic multiplanar and volume-rendered reconstructions were used to evaluate bowel wall thickness, ulceration, contrast enhancement, extraparietal involvement and possible complications.

RESULTS

MDCT enteroclysis identified the typical signs of Crohn's disease in 26 patients (92.8%), with sensitivity of 92.8%, specificity of 100%, positive predictive value 100% and negative predictive value 75%.

CONCLUSIONS

MDCT enteroclysis after oral hyperhydration with isotonic solution showed a high level of accuracy in detecting small bowel changes in patients with Crohn's disease. It can be considered a safe and effective alternative to conventional radiography and small-bowel spiral computed tomography enema, especially in patients who refuse nasojejunal intubation.

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.

Possible small-bowel neoplasms: contrast-enhanced and water-enhanced multidetector CT enteroclysis

PURPOSE

To prospectively evaluate the sensitivity and specificity of contrast material-enhanced and water-enhanced multidetector computed tomographic (CT) enteroclysis in depicting small-bowel neoplasms in symptomatic patients, with endoscopic, tissue, and follow-up findings as reference standards.

MATERIALS AND METHODS

The study protocol was approved by the Human Research Committee of the institution, and all patients gave written informed consent. Two hundred nineteen patients (108 male, 111 female; age range, 17-98 years; mean, 53.1 years) with clinical suspicion of small-bowel neoplasm underwent contrast- and water-enhanced multidetector CT enteroclysis after normal findings of upper and lower gastrointestinal endoscopy. The prospective interpretations of CT enteroclysis results include evaluation of focal bowel wall thickening, small-bowel masses, small-bowel stenosis, mesenteric stranding, enlarged mesenteric lymph nodes, and visceral metastasis. Positive enteroclysis findings were compared with results of pathologic examination after surgical (n = 35) or endoscopic (n = 20) procedures. Negative results were compared with results of surgery (n = 8), enteroscopy (n = 15), capsule endoscopy (n = 14), and clinical follow-up (n = 127). Sensitivity, specificity, accuracy, and positive and negative predictive values were calculated on a per-patient basis with 95% confidence intervals.

RESULTS

Findings of CT enteroclysis were positive in 55 cases and negative in 164. The overall sensitivity and specificity in identifying patients with small-bowel lesions were 84.7% and 96.9%, respectively. The negative and positive predictive values were 94.5% and 90.9%, respectively. Findings of pathologic examination confirmed small-bowel tumor in 50 patients with carcinoid tumor (n = 19), adenocarcinoma (n = 7), lymphoma (n = 5), jejunal adenoma (n = 9), stromal tumor (n = 5), ectopic pancreas (n = 2), angiomatous mass (n = 2), or metastasis (n = 1). Five examinations resulted in false-positive findings.

CONCLUSION

Contrast- and water-enhanced multidetector CT enteroclysis had an overall accuracy of 84.7% for depiction of small-bowel neoplasms.

Hydro-MRI of the small bowel: effect of contrast volume, timing of contrast administration, and data acquisition on bowel distention

OBJECTIVE

The purpose of this study was to assess oral contrast agents, volumes of the agents, and time points of data acquisition in regard to small-bowel distention and patient acceptance.

SUBJECTS AND METHODS

Six healthy volunteers underwent imaging on 16 different days. Four volumes (450, 900, 1,350, and 1,800 mL) of each of the four contrast compounds (0.2% locust bean gum plus 2.5% mannitol, VoLumen containing 2.0% sorbitol, VoLumen containing 1.4% sorbitol, and tap water) were used. Two-dimensional true fast imaging with steady-state free precession data sets were acquired at 5-minute intervals after contrast ingestion. Distention values for small-bowel segments (duodenum, proximal and distal jejunum, ileum) and occurrence of side effects were documented.

RESULTS

Analysis of bowel distention revealed significantly greater distention for all carbohydrate sugar alcohol-containing solutions compared with water but no significant difference among the three contrast agents. Sufficient duodenal distention was achieved with 900 mL of any of the contrast agents, but imaging had to be performed soon after ingestion. For MRI of the distal jejunum and ileum, a volume of 1,350 mL is preferable, and the time point of data acquisition plays a minor role. Ingestion of 1,800 mL of the carbohydrate sugar alcohol solutions led to a significantly higher rate of side effects such as abdominal cramps than did ingestion of smaller volumes.

CONCLUSION

The data indicate that sufficient contrast consumption and optimal timing of data acquisition are essential to distention of the small bowel. Oral contrast agent protocols should be adapted to the bowel region in question.

Assessment of Crohn's disease in the small bowel: Prospective comparison of magnetic resonance enteroclysis with conventional enteroclysis

Our objective was to assess the diagnostic value of magnetic resonance enteroclysis (MRE) compared with conventional enteroclysis (CE) in patients with Crohn's disease. A secondary objective was to evaluate the diagnostic accuracy of each different MR sequence. Sixty-six consecutive patients with known Crohn's disease underwent MRE and CE. Fast imaging employing steady-state acquisition (FIESTA), single-shot fast spin-echo (ssFSE), and contrast-enhanced T1-weighted sequences were assessed by two radiologists who reached a consensus about the following findings: visualization of wall ulcers, pseudopolyps, fistulae, mural stenosis, and mesenteric abnormalities. Standard descriptive statistics and the McNemar test were used. The sensitivity, specificity and accuracy of MRE were 90-87% and 83% for the depiction of parietal ulcers, 84%-88% and 86% for pseudopolyps, 100-94% and 96% for mural stenosis, 93-100% and 94% for fistulae. The number of detected extraluminal findings was significantly higher with MRE (P < 0.01). The accuracy of FIESTA sequence was statistically higher in the depiction of wall ulcers and fistulae than that of three-dimensional fast spoiled gradient echo (3D-FSPGR) (P < 0.01) and ssFSE (P < 0.05) sequences. Contrast-enhanced 3D-FSPGR was superior for mural stenosis visualization compared to ssFSE (P < 0.05) and FIESTA (P < 0.05). MRE correlates accurately with CE in the detection of superficial and transmural abnormalities and has the advantage of assessing the mesenteric manifestations.

Obscure gastrointestinal bleeding

Obscure GI bleeding is a relatively common problem facing internists, gastroenterologists, and surgeons in a typical clinical practice. The etiology is occasionally suggested by the patient's age, history, and medications. Management is complicated and typically requires a team-oriented approach, with input from the internist, gastroenterologist, radiologist, and surgeon alike. SBFT and enteroclysis seem to have a limited role, unless there is a high suspicion of a small bowel mass lesion or Crohn's disease. Scintigraphy may be performed in patients with active bleeding in whom endoscopy has failed oris contraindicated. Angiography may be used in patients with an early positive nuclear imaging or failed endoscopic therapy. Provocative angiography probably has a lower diagnostic yield than previously reported, and should be performed only in experienced centers. Helical CT is a new and potentially important option in patients with obscure bleeding, but is currently considered experimental. All patients with obscure GI bleeding should undergo repeat upper endoscopy and perhaps colonoscopy to rule out missed lesions. SBE seems to be complementary to capsule endoscopy, and it is unknown whether this should be performed before capsule endoscopy or only if capsule endoscopy yields a positive proximal small bowel finding. Double balloon enteroscopy seems promising, but the technique requires further study. Surgery should be reserved for patients who have a positive capsule endoscopy requiring surgical therapy or patients who have persistent GI bleeding requiring recurrent blood transfusions in whom all other modalities have failed. Treatment for vascularectasias, the most common cause of obscure GI bleeding, is currently inadequate,and typically requires a combination of multiple management approaches.

A prospective comparison study of MRI versus small bowel follow-through in recurrent Crohn's disease

BACKGROUND

We aimed to determine the utility of magnetic resonance imaging (MRI) compared with small bowel follow-through (SBFT) in the assessment of known Crohn's disease.

METHODS

Subjects, over age 18 yr who were to undergo SBFT investigations to assess for complications or extent of Crohn's disease were eligible. SBFT was performed by a single radiologist (IB), and within 4 wk MRI was performed by a single radiologist (HG) who was blinded to the SBFT results. For MRI, oral contrast was 2% barium sulfate (1,350 mL). After unenhanced T1 weighted images and single shot fast spin echo T2 imaging, intravenous (IV) glucagon and gadolinium were given. Fast multiplanar spoiled-gradient recalled T1 coronal sequences were obtained followed by abdominal and pelvic axial images. MRI and SBFT were compared for extent of disease, presence of complications, and for identification of extraintestinal disease.

RESULTS

Paired studies were undertaken within a mean of 22 days in 30 subjects. Ten studies were normal by both modalities and 8 studies showed similar extent of Crohn's disease. SBFT revealed additional information in 4, including a stricture in 1 and ileosigmoid fistulas in 2. MRI provided enhanced information in 8, including identifying active inflammation in strictured areas based on wall enhancement patterns, vasa recta changes, and lymphadenopathy.

CONCLUSIONS

On the basis of cost and accessibility, SBFT may still be a first line procedure of choice in some centers without MRI, but MRI's advantages of no radiation and the potential to identify active inflammation in strictured areas, extraintestinal, and colorectal disease make it an attractive alternative.

MRI in Crohn's disease

Technological developments have extended the role of MRI in the evaluation of the gastrointestinal tract. The potential of MRI to evaluate disease activity in Crohn's disease has been investigated extensively, as MRI has intrinsic advantages over other techniques, including noninvasiveness and the absence of ionizing radiation. For perianal fistulizing disease MRI has become a mainstay in evaluation of disease, as localization and extent of disease can be very well appreciated using both T2-weighted and T1-weighted sequences, fat suppression, and intravenous contrast medium. Imaging of the small bowel and colon in Crohn's disease is more complicated due to bowel peristalsis and respiratory movement. However, using fast breathhold sequences and intravenous spasmolytic medication, images of good diagnostic quality can be acquired. To obtain sufficiently distended bowel, which in our estimation is a prerequisite for evaluation of the bowel, MR enteroclysis can be performed. However, applicability of different oral contrast media has been studied, as a noninvasive method for bowel distension would be preferable. Abdominal MRI is a valuable imaging technique for evaluation of luminal, transmural, and extraintestinal manifestations of Crohn's disease as degree of disease activity, presence of luminal pathology (e.g., stenoses), and extraintestinal manifestations of disease (e.g., abscesses, fistulas) can be accurately assessed.

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.

Diagnosing Crohn's disease: an economic analysis comparing wireless capsule endoscopy with traditional diagnostic procedures

The purpose of this study was to review economic considerations related to establishing a diagnosis of Crohn's disease, and to compare the costs of a diagnostic algorithm incorporating wireless capsule endoscopy (WCE) with the current algorithm for diagnosing Crohn's disease suspected in the small bowel. Published literature, clinical trial data on WCE in comparison to other diagnostic tools, and input from clinical experts were used as data sources for (1) identifying contributors to the costs of diagnosing Crohn's disease; (2) exploring where WCE should be placed within the diagnostic algorithm for Crohn's; and (3) constructing decision tree models with sensitivity analyses to explore costs (from a payor perspective) of diagnosing Crohn's disease using WCE compared to other diagnostic methods. Literature review confirms that Crohn's disease is a significant and growing public health concern from clinical, humanistic and economic perspectives, and results in a long-term burden for patients, their families, providers, insurers, and employers. Common diagnostic procedures include radiologic studies such as small bowel follow through (SBFT), enteroclysis, CT scans, ultrasounds, and MRIs, as well as serologic testing, and various forms of endoscopy. Diagnostic costs for Crohn's disease can be considerable, especially given the cycle of repeat testing due to the low diagnostic yield of certain procedures and the inability of current diagnostic procedures to image the entire small bowel. WCE has a higher average diagnostic yield than comparative procedures due to imaging clarity and the ability to visualize the entire small bowel. Literature review found the average diagnostic yield of SBFT and colonoscopy for work-up of Crohn's disease to be 53.87%, whereas WCE had a diagnostic yield of 69.59%. A simple decision tree model comparing two arms--colonoscopy and SBFT, or WCE--estimates that WCE produces a cost savings of 291dollars for each case presenting for diagnostic work-up for Crohn's. Sensitivity analysis varying diagnostic yields of colonoscopy and SBFT vs. WCE demonstrates that WCE is still less costly than SBFT and colonoscopy even at their highest reported yields, as long as the diagnostic yield of WCE is 64.10% or better. Employing WCE as a first-line diagnostic procedure appears to be less costly, from a payor perspective, than current common procedures for diagnosing suspected Crohn's disease in the small bowel. Although not addressed in this model, earlier diagnosis with WCE (due to higher diagnostic yield) also could lead to earlier management, improved quality of life and workplace productivity for people with Crohn's disease.

Noninvasive diagnosis of small bowel Crohn's disease: combined use of bowel sonography and Tc-99m-HMPAO leukocyte scintigraphy

BACKGROUND

Crohn's disease (CD) is frequently localized in the small bowel, with the diagnosis of disease and the assessment of its extension made by ileo-colonoscopy (IC) and small bowel enteroclysis (SBE). Transabdominal bowel sonography (BS) and Tc-99m-HMPAO leukocyte scintigraphy (LS) are increasingly used for the diagnosis of CD because of their minimal invasiveness, reproducibility, and acceptable costs.

METHODS

From March 2000 to July 2003, we performed IC, SBE, BS, and LS in 84 patients with either suspected or known small bowel CD.

RESULTS

Small bowel CD was present in 50 patients, whereas the other 34 patients received a different diagnosis. Sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy were, respectively, 98%, 97%, 98%, 97%, and 0.97 for SBE; 92%, 97%, 98%, 88%, and 0.94 for BS; and 90%, 93%, 96%, 85%, and 0.92 for LS. In addition, the combined use of BS and LS led to overall sensitivity, specificity, positive and negative predictive values, and diagnostic accuracy of 100%, 93%, 96%, 100%, and 0.97, respectively. BS showed a fair concordance with SBE in terms of location (k = 0.71) and a correlation with the extension of the disease (r = 0.67, P < 0.001). LS showed a concordance with SBE with regard to location in about one-half the population (k = 0.54), whereas it was less effective than SBE in defining disease extension.

CONCLUSIONS

BS and LS are 2 accurate techniques for the diagnosis of small bowel CD, and their combined use can be recommended as an early diagnostic approach to patients in which the disease is suspected. SBE remains the best procedure for the definition of the location and extension of the disease.

Oral contrast agents for small bowel distension in MRI: influence of the osmolarity for small bowel distention

To assess the effect of the osmolarity for small bowel distension in MRI, ten volunteers ingested at two separate occasions negative oral contrast agents with different quantity and osmolarity: (1) a water solution combined with 2.0% sorbitol and 0.2% locus bean gum (LBG) with a quantity of 1500 ml and an osmolarity of 148 mOsmol/l, (2) a water solution combined with 2.0% sorbitol and 2.0% barium sulphate with a quantity of 1000 ml and an osmolarity of 194 mOsmol/l. Small bowel distension was quantified on coronal 2D-TrueFISP images by measuring the small bowel diameters. There were no statistically significant differences in mean small bowel diameter between both contrast agents. The mean small bowel distension was 19.2 mm after ingestion of 1500 ml of sorbitol-LBG solution and 19.0 mm after ingestion of 1000-ml sorbitol-barium sulphate solution. Furthermore, all volunteers found the ingestion of 1000-ml solution more pleasant than the 1500-ml solution. The ingestion of 1000 ml of sorbitol-barium sulphate solution led to a sufficient small bowel distension compared to 1500 ml of sorbitol-LBG solution. The side effect rate of both solutions was low. Based on these data, we recommend a quantity of 1000 ml of sorbitol-barium sulphate solution as an alternative for 1500-ml sorbitol-LBG solution for optimal bowel distension.

Dose optimization of mannitol solution for small bowel distension in MRI

PURPOSE

To optimize the dose of a hydro solution containing 2.5% mannitol and 0.2% locust bean gum (LBG) for small bowel MRI in terms of bowel distension and patient acceptance.

MATERIALS AND METHODS

A total of 10 healthy volunteers ingested a hydro solution containing 2.5% mannitol and 0.2% LBG. Four different volumes (1500, 1200, 1000, and 800 ml) were assessed on four different examination days. Small bowel distension was quantified on coronal two-dimensional TrueFISP images by measuring the diameter of eight bowel loops throughout the jejunum and the ileum. In addition, volunteer acceptance was evaluated for every single examination by using a questionnaire.

RESULTS

Optimal distension was obtained with either, 1000, 1200, or 1500 ml, with no statistically significant differences in distension between these groups. Administration of 800 ml led to significantly less distension of the small bowel. Significantly less side effects were noted using either 800 or 1000 ml compared to using larger volumes.

CONCLUSION

We recommend a dose of 1000 ml mannitol/LBG solution as an oral contrast agent for optimal bowel distension and minimal side effects.

Small intestine contrast ultrasonography: an alternative to radiology in the assessment of small bowel disease

BACKGROUND

Radiology and transabdominal ultrasonography (TUS) are used in the evaluation of the small bowel; however, the former technique is limited by radiation exposure, and the latter by its inability to visualize the entire small bowel.

AIM

To evaluate the diagnostic accuracy of small intestine contrast ultrasonography (SICUS) to assess the presence, number, site, and extension of small bowel lesions.

SUBJECTS AND METHODS

TUS, SICUS, and small bowel follow-through (SBFT) were performed in 148 consecutive patients (78 women; age range, 12 to 89 yr), 91 with undiagnosed conditions, and 57 with previously diagnosed Crohn's disease (CD).

RESULTS

In the undiagnosed patients, the sensitivity and specificity of TUS and SICUS were 57% and 100%, and 94.3% and 98%, respectively. In the CD patients, the sensitivity of TUS and SICUS was 87.3% and 98%, respectively. In comparison with SBFT, the extension of lesions was correctly assessed with SICUS and greatly underestimated with TUS. The concordance index between SBFT and SICUS for the number and site of lesions was 1 and 1 (P < 0.001), respectively, in undiagnosed patients, and 0.81 and 0.83 (P < 0.001), respectively, in CD patients. Between SBFT and TUS, the concordance index was 0.28 and 0.27 (not significant), respectively, in undiagnosed patients, and 0.28 and 0.31 (not significant), respectively, in CD patients.

CONCLUSIONS

The diagnostic accuracy of SICUS is comparable to that of a radiologic examination, and is superior to that of TUS in detecting the presence, number, extension, and sites of small bowel lesions. These findings support the use of noninvasive SICUS for an initial investigation when small bowel disease is suspected and in the follow-up of CD patients.

Small bowel hydro-MR imaging for optimized ileocecal distension in Crohn's disease: Should an additional rectal enema filling be performed?

PURPOSE

To assess the impact of an additional rectal enema filling in small bowel hydro-MRI in patients with Crohn's disease.

MATERIALS AND METHODS

A total of 40 patients with known Crohn's disease were analyzed retrospectively: 20 patients only ingested an oral contrast agent (group A), the other 20 subjects obtained an additional rectal water enema (group B). For small bowel distension, a solution containing 0.2% locust bean gum (LBG) and 2.5% mannitol was used. In all patients, a breathhold contrast-enhanced T1w three-dimensional volumetric interpolated breathhold examination (VIBE) sequence was acquired. Comparative analysis was based on image quality and bowel distension as well as signal-to-noise ratio (SNR) measurements. MR findings were compared with those of conventional colonoscopy, as available (N = 25).

RESULTS

The terminal ileum and rectum showed a significantly higher distension following the rectal administration of water. Furthermore, fewer artifacts were seen within group B. This resulted in a higher reader confidence for the diagnosis of bowel disease, not only in the colon, but also in the ileocecal region. Diagnostic accuracy in diagnosing inflammation of the terminal ileum was 100% in group B; in the nonenema group there were three false-negative diagnoses of terminal ileitis.

CONCLUSION

Our data show that the additional administration of a rectal enema is useful in small bowel MRI for the visualization of the terminal ileum. The additional time needed for the enema administration was minimal, and small and large bowel pathologies could be diagnosed with high accuracy. Thus, we suggest that a rectal enema in small bowel MR imaging be considered.

MRI for small bowel diseases

The role of radiologic studies has been well established in the diagnosis and management of patients with small bowel diseases. While small bowel follow-through examination or enteroclysis is widely accepted as the primary imaging method for small bowel investigation, additional cross-sectional imaging studies are often required for an accurate diagnosis and the precise evaluation of the extraluminal disease. Since fast magnetic resonance imaging (MRI) sequences have become available, there is increasing interest in the use of MRI for small bowel evaluation, attributed to its inherent advantages such as the lack of radiation exposure, excellent soft tissue contrast, and direct multiplanar capabilities. In this article, we review the current techniques, clinical applications, and limitations of MRI for the evaluation of patients with small bowel diseases.