Evidence-Based Review of Current Cross-Sectional Imaging of Inflammatory Bowel Disease

CT and MR enterography are cross-sectional imaging examinations used in the assessment of inflammatory bowel disease. Consistent reporting and standardized nomenclature are important for clear communication with referring clinicians. Enterography has not only been used to depict inflammation in the small bowel, but it has also been used to quantify disease activity, assess distribution of disease, and detect complications including penetrating disease. This article reviews cross-sectional imaging findings in inflammatory bowel disease, including the current literature focusing on small bowel Crohn's disease and ulcerative colitis, with evidence-based guidelines on appropriate protocols and imaging procedures.

Bowel preparation after mid-gut tubing enhanced the efficacy and compliance of magnetic resonance enterography in Crohn's disease: a randomized controlled trial

Background

Magnetic resonance enterography (MRE) has become a routine intestinal imaging examination for Crohn's disease (CD). Sufficient bowel preparation is fundamental for MRE.

Objectives

To compare the efficacy and compliance of bowel preparation between through a mid-gut tube and oral administration for MRE in CD.

Design

This was an open-label, prospective, multicenter, randomized controlled trial.

Methods

Eligible patients were randomized at a 1:1 ratio into an oral group (bowel preparation by oral administration) and a tubing group (bowel preparation through a mid-gut tube). Bowel preparation for MRE included bowel cleaning and bowel distention. The primary outcomes were the degree of discomfort and grade of bowel distention. The secondary outcomes were diagnostic accuracy rate through MRE, mental stress, and bowel preparation method preference.

Results

A total of 95 CD patients were included in the final analysis. Subjects in the tubing group complained of less vomiting during bowel preparation than those in the oral group (p < 0.05). The degree of nausea and bloating during bowel cleaning for MRE was lower in the tubing group than in the oral group (all p < 0.05). The distention grade was higher in the tubing group compared to the oral group in the splenic flexure of the colon and rectosigmoid colon. The tubing group demonstrated a higher overall diagnostic sensitivity in ulcers compared to the oral group (p = 0.048). Additionally, bowel preparation via the mid-gut tube ameliorated mental stress (p = 0.020) and increased bowel preparation preference (p < 0.001).

Conclusion

Bowel preparation through the mid-gut tube enhanced the efficacy and compliance for MRE in CD. This study highlighted the concept of physician-patient satisfaction using mid-gut tube for proper bowel preparation for MRE, enteral nutrition and microbial therapy.

Trial registration

ClinicalTrials.gov, NCT03541733, registered 5 May 2018.

Exploring the Use of Computed Tomography Enterography in the Evaluation of Small Bowel Disease: A Prospective Study

Background A major development in noninvasive imaging modalities, computed tomographic enterography (CTE) has a number of benefits over conventional computed tomography (CT) and capsule endoscopy. Through the utilization of multidetector computed tomography (MDCT) technology, CTE expedites the assessment of small bowel diseases, especially in those segments that are not accessible through traditional endoscopy. This study's main goal is to thoroughly evaluate CTE's diagnostic accuracy for a range of small intestinal conditions. Methodology In this investigation, which is a prospective observational study, 40 patients, 25 men and 15 women, with suspected small intestinal disorders and ages ranging from 10 to 70 underwent CTE. To evaluate diagnosis accuracy, a combination of clinical symptoms, imaging data, and histopathological/ultrasonography findings were evaluated. Throughout the research procedure, ethical issues and statistical analysis were incorporated to guarantee validity and adherence to ethical norms. Results The most frequent findings on CTE were bowel thickening and mucosal hyperenhancement, which were seen in 25 (62.5%) and 20 (50%) of the patients, respectively. The majority of patients (65%) exhibited both the ileal and jejunal loops to be adequately distended in grade III. In 35% of the patients, grade II distensibility of the ileal and jejunal loops was seen. Conclusion When it comes to accurately detecting small intestinal disorders, CTE is superior. It evaluates extraintestinal, mural, and intraluminal diseases with efficacy, particularly in places that are difficult to reach. It is essential for directing clinical decisions because of its capacity to assess disease activity prior to endoscopy and see consequences.

Comparison of the Efficacy of Diluted Polyethylene Glycol and Low-Density (0.1% w/v) Barium Sulfate Suspension for CT Enterography

PURPOSE

To compare small bowel distension and side effects between a diluted polyethylene glycol (PEG) solution and a low-density (0.1% w/v) barium sulfate suspension (LDBSS) for CT enterography (CTE) preparation.

MATERIALS AND METHODS

Total 173 consecutive patients who underwent CTE were enrolled in this study. The LDBSS (1 L) was used in 50 patients, and the diluted iso-osmotic PEG solution (1 L) was used in 123 patients. Two blinded radiologists independently scored jejunal and ileal distensions on a 5-point scale. To compare side effects between the two groups, the patients reported whether they had immediate complications after the administration of the oral contrast media.

RESULTS

For ileal and jejunal distension, the diluted PEG solution showed no difference from the LDBSS for either reader (ileum: reader 1, median, 4; 4, interquartile range, 3-4; 3-4, p = 0.997; reader 2, median, 4; 4, interquartile range, 3.3-4.0; 3-4, p = 0.064; jejunum: reader 1, median, 2; 2, interquartile range, 2-3; 2-3, p = 0.560; reader 2, median, 3; 2, interquartile range, 2-3; 2-3, p = 0.192). None of the patients complained of immediate complications following administration of either of the oral contrast media.

CONCLUSION

The diluted PEG solution showed comparable bowel distension compared to LDBSS and no immediate side effects; thus, it can be a useful alternative.

A novel food-based foam as oral contrast agent with negative Hounsfield units for demarcation of small bowel loops on abdominal CT: tolerability and bowel distension in 25 volunteers

BACKGROUND

Diseases of the bowel are not always displayed on conventional abdominal computed tomography (CT). The studied oral contrast agent aims to improve this.

PURPOSE

To investigate whether the use of a novel oral contrast for abdominal CT enables the same diagnostic advantages as seen in magnetic resonance imaging (MRI).

MATERIAL AND METHODS

Twenty-five consented volunteers drank up to 1400 mL of a stable, drinkable foam. Comments on acceptance and side effects were noted immediately and 24 h later. Foam palatability was documented through interviews, and distribution in the small bowel by Hounsfield units from the CT software. The CT results were compared with age- and sex-matched controls, pretreated according to routine. A non-enhanced abdominal CT protocol of lowest possible radiation dose was used. External referees evaluated all data obtained.

RESULTS

Foam was considered odd to swallow, and fullness was reported by all volunteers after 950 mL. Five had difficulties in drinking the last 320 mL and two abstained from it. All adverse symptoms were mild. The distribution in the small bowel was on par with standard agents. Foam density revealed stability with intraluminal values of around -550 HU from stomach to terminal ileum, satisfying the requirement of a great bowel lumen-to-wall contrast. External reviewers re-evaluated all our data, and one predicted the foam to offer a potential for improved diagnostics.

CONCLUSION

A CT true-negative bowel filling agent was formulated, with high acceptance, few side effects, and a potential to mimic T1-weighted MRI images.

COMPARATIVE ANALYSIS OF TWO ORAL CONTRAST AGENT VOLUMES FOR COMPUTED TOMOGRAPHY ENTEROGRAPHY IN CROHN'S DISEASE PATIENTS

BACKGROUND

Crohn's disease (CD) is an inflammatory bowel disease characterized by a chronic and recurrent inflammation of the gastrointestinal tract caused by an interaction of genetic and environmental factors.

OBJECTIVE

To compare the quality and acceptance of two different oral contrast volumes for computed tomography enterography in Crohn's disease patients.

METHODS

A cross-sectional study was conducted in 58 consecutive Crohn's disease patients who randomly received an oral contrast agent composed of 78.75 g polyethylene glycol diluted in either 1,000 mL or 2,000 mL of water. An examination was performed to evaluate the presence of inflammation or complications in the small bowel. The variables included the quality of intestinal segment filling and luminal distension, and oral contrast agent acceptance and tolerance in the patients. Statistical analysis included descriptive statistics and association tests.

RESULTS

A total of 58 patients were assessed, in which 58.6% were female, 34.5% exhibited clinically-active disease, and 63.8% were receiving biologic therapy. As for comparative analysis between the two different volumes of oral contrast, no statistically significant difference was found regarding bowel loop filling (P=0.58) and adequate luminal distension (P=0.45). Patients who received a larger volume (2,000 mL) exhibited side-effects more frequently (51.7% vs 31.0%; P=0.06) and had greater difficulty ingesting the agent (65.5% vs 37.9%; P=0.07) compared with a volume of 1,000 mL.

CONCLUSION

The quality of computed tomography enterography was not influenced by the contrast volume. However, acceptance and tolerance were better in the 1,000 mL group.

State of the Art MR Enterography Technique

ABSTRACT

Magnetic resonance enterography (MRE) is a well-established imaging technique that is commonly used for evaluating a variety of bowel diseases, most commonly inflammatory bowel disease which is increasing in prevalence. Inflammatory bowel disease is composed of 2 related, but distinct disease entities: Crohn disease (CD) and ulcerative colitis. In ulcerative colitis, inflammation is generally limited to the mucosa and invariably involves the rectum, and often the more proximal colon. CD is typified by transmural inflammation with skip lesions occurring anywhere from the mouth to anus, but characteristically involves the terminal ileum. The transmural involvement of CD may lead to debilitating ulceration and, ultimately, development of sinus tracts, which can be associated with abscesses and fistulae as extraenteric manifestations of the disease. Because much of the small bowel and extraenteric disease cannot be adequately assessed with conventional endoscopy, imaging plays a crucial role in initial diagnosis and follow-up. MRE does not use ionizing radiation which is important for these patients, many of which present earlier in life and may require multiple imaging examinations. In this article, we review the clinical indications, patient preparation, and optimal technique for MRE. We also discuss the role and proper selection of intravenous gadolinium-based contrast material, oral contrast material, and antiperistaltic agents, including pediatric considerations. Finally, we review the recommended and optional pulse sequence selection, including discussion of a "time-efficient" protocol, reviewing their utility, advantages, and limitations. Our hope is to aid the radiologist seeking to develop a robust MRE imaging program for the evaluation of bowel disease.

Elimination of oral contrast leads to faster scans in the workup of abdominal pain in the emergency setting without compromising diagnostic accuracy

INTRODUCTION

The aim of this study was to study how the effect of eliminating oral contrast for computed tomography of the abdomen and pelvis (CTAP) in the workup of abdominal pain in the emergency department (ED) would affect the time from patient review to scan and time from review to discharge.

METHODS

In this retrospective study, we analysed all ED presentations with abdominal pain to our university affiliated tertiary hospital before and after a protocol that eliminated oral contrast-enhanced CTAPs were implemented in September 2018. Two equivalent periods between September and November of 2017 and 2018 were analysed. Patients were excluded if they had a history of anatomy-altering gastrointestinal surgery, history of inflammatory bowel disease, trauma, suspicion of foreign body ingestion or suspected gastrointestinal bleeding.

RESULTS

A total of 176 pre-protocol and 197 post-protocol patients were included in the study. We found that the elimination of oral contrast was associated with a decrease in mean time between ED review and scan by 110 min (379 vs. 269 min). We also found that the elimination of oral contrast did not significantly alter the pattern of radiological diagnoses seen between the two study periods, suggesting the absence of oral contrast does not affect diagnostic accuracy.

CONCLUSION

Thus, eliminating the use of oral contrast in the workup of abdominal pain in the ED can lead to increased throughput and more timely patient care.

Which MRI Score and Technique Should Be Used for Assessing Crohn's Disease Activity?

Magnetic resonance (MR) enterography is assuming an increasingly important and central role in the management of patients with Crohn’s disease, as it is not only involved in diagnosis and staging of the disease but also allows for patients’ follow-up, evaluating the response to therapy, and predicting disease outcomes. Several MR scores have been developed but unfortunately there is no globally accepted score. The most widely used scores are the Magnetic Resonance Index of Activity (MaRIA) score, the London score, the Nancy score, and the Clermont score; however, there are multiple differences between these tools in terms of the assessed radiological items, fasting, administration of oral or intravenous contrast, and the use of diffusion-weighted images. Here we reviewed the main characteristics of each MR scoring system to clarify which is the most appropriate score for monitoring disease activity in both clinical practice and clinical trials.

Comparison of two small bowel distending agents for enterography in pediatric small bowel imaging

OBJECTIVE

To evaluate the ability of pediatric patients with known or suspected inflammatory bowel disease to ingest a new oral distending agent at CT or MR enterography (CTE/MRE), and to determine the impact on small bowel (SB) distension and diagnostic confidence.

MATERIALS AND METHODS

The study design is that of retrospective review of pediatric patients who underwent CTE or MRE from January 2014 to June 2016. Patients ingested low-concentration barium suspension or flavored beverage containing sorbitol and mannitol. The need for nasogastric tube (NGT) administration, amount ingested, emesis, distal extent of contrast, SB distension, terminal ileum (TI) transverse dimension, and diagnostic confidence in TI disease were assessed. Three radiologists each blindly reviewed a subset of the studies.

RESULTS

Of the total 591 scans in 504 patients, 316 scans used low-concentration barium suspension and 275 scans flavored beverage. Nearly all consumed the entire amount (97% vs. 96%). Low-concentration barium suspension exams required NGT more often (7% [23/316] vs. 1% [3/275]; p < 0.0003), and tended to have more emesis (3% [9/316] vs. 1% [3/275]; p = 0.13). Diagnostic confidence score was nearly identical (p = 0.94). Qualitative and quantitative analyses showed no difference in SB distension, except for distension of mid-ileum (flavored beverage > low-concentration barium suspension; p = 0.02). Flavored beverage exams demonstrated a slight increase in distal extent of luminal distension (p = 0.02).

CONCLUSIONS

A new flavored beverage distends small bowel as well as low-concentration barium suspension, with decreased requirement for NGT insertion and improved distal extent of luminal distension, and without any decrease in diagnostic confidence in the presence or the absence of TI disease.

The Influence of Bowel Preparation on ADC Measurements: Comparison between Conventional DWI and DWIBS Sequences

Background and objectives: The aim of the study was to assess whether there were differences between apparent diffusion coefficient (ADC) values of diffusion-weighted imaging (DWI) and diffusion-weighted imaging with background body signal suppression (DWIBS) sequences in non-prepared and prepared bowels before and after preparation with an enteric hyperosmolar agent, to assess whether ADC measurements have the potential to avoid bowel preparation and whether ADC-DWIBS has advantages over ADC-DWI. Materials and Methods: 106 adult patients without evidence of inflammatory bowel disease (IBD) underwent magnetic resonance (MR) enterography before and after bowel preparation. ADC-DWI and ADC-DWIBS values were measured in the intestinal and colonic walls demonstrating high signal intensity (SI) at DWI tracking images of b = 800 s/mm² before and after preparation. Results: There were significant difference (p < 0.0001) in both ADC-DWI and ADC-DWIBS results between non-prepared and prepared jejunum for DWI being 1.09 × 10⁻³ mm²/s and 1.76 × 10⁻³ mm²/s, respectively, and for DWIBS being 0.91 × 10⁻³ mm²/s and 1.75 × 10⁻³ mm²/s, respectively. Both ADC-DWI and DWIBS also showed significant difference between non-prepared and prepared colon (p < 0.0001), with DWI values 1.41 × 10⁻³ mm²/s and 2.13 × 10⁻³ mm²/s, and DWIBS—1.01 × 10⁻³ mm²/s and 2.04 × 10⁻³ mm²/s, respectively. No significant difference between ADC-DWI and ADC-DWIBS was found in prepared jejunum (p = 0.84) and prepared colon (p = 0.58), whereas a significant difference was found in non-prepared jejunum and non-prepared colon (p = 0.0001 in both samples). Conclusions: ADC between DWI and DWIBS does not differ in prepared bowel walls but demonstrates a difference in non-prepared bowel. ADC in non-prepared bowel is lower than in prepared bowel and possible overlap with the ADC range of IBD is possible in non-prepared bowel. ADC-DWIBS has no advantage over ADC-DWI in regard to IBD assessment.

Comparison of three oral contrast preparations for magnetic resonance enterography in pediatric patients with known or suspected Crohn disease: a prospective randomized trial

BACKGROUND

Oral contrast preparation is fundamental to ensuring diagnostic examination quality for magnetic resonance enterography (MRE), yet little is known about the relative palatability and tolerability of various oral contrast agents in pediatric patients with known or suspected inflammatory bowel disease.

OBJECTIVE

We prospectively compared three MRE oral preparations in pediatric patients with known or suspected Crohn disease with respect to patient-reported tolerability and radiologist-determined small-bowel distension and opacification.

MATERIALS AND METHODS

Seventy-five pediatric patients (mean age 14.8 years, 55% female) with known or suspected Crohn disease referred for MRE were randomized to an oral preparation with a sugar alcohol-based flavored beverage (Breeza), polyethylene glycol preparation (MiraLAX), or low-concentration barium sulfate suspension (VoLumen). Patients were instructed to consume oral contrast agent (using a weight-based protocol) beginning 60 min prior to MRE imaging. Following MRE, patients completed a questionnaire regarding their oral preparation solution including: taste (1-5 scale), feeling of well-being (1-5 scale) and willingness to consume again (yes/no). Two radiologists reviewed all MRE exams and rated exams for global features (active disease, overall small-bowel distention [1-4 scale]) and features specific to individual small-bowel segments (extent of distention, maximal luminal diameter, opacification, and susceptibility artifact). Statistical methods included one-way analysis of variance (ANOVA) with Tukey honest difference and Fisher exact tests.

RESULTS

The overall rate of completion of the entire prescribed contrast volume was 53% (40/75), with a significantly higher rate of completion for MiraLAX than for VoLumen (70% vs. 30%, P=0.007). Crossover to a different preparation occurred in nine patients (12%) and was significantly more frequent when the initial preparation was VoLumen versus MiraLAX (29% vs. 0%, P=0.005). Mean subjective taste ratings for both MiraLAX (3.4, P<0.0001) and Breeza (2.8, P=0.006) were superior to those of VoLumen (1.9), which persisted in the subset of patients with MRE evidence of active Crohn disease. Patients who consumed MiraLAX were more likely to be willing to drink it again compared to those consuming VoLumen (82% vs. 46%, P=0.009). Overall small-bowel distention and bowel-segment-specific metrics (distention, maximal diameter, opacification and susceptibility) did not significantly differ among groups.

CONCLUSION

In pediatric patients with known or suspected Crohn disease, MiraLAX and Breeza were rated as more palatable than VoLumen, and all three preparations achieved a similar degree of small-bowel distension and opacification on MRE. Imaging centers performing MRE should stock multiple oral contrast preparations because a sizable proportion of children require more than one agent to ingest the requisite oral contrast volume.

Comparison of Positive Oral Contrast Agents for Abdominopelvic CT

OBJECTIVE. The objective of our study was to compare the quality of bowel opacification from three different positive oral contrast agents-barium sulfate, diatrizoate, and iohexol-at abdominopelvic CT. MATERIALS AND METHODS. Abdominopelvic CT examinations with three different oral contrast agents (each contrast agent: n = 300 patients) of 900 patients were retrospectively evaluated by two independent readers. For four segments of the gastrointestinal tract (i.e., the stomach, jejunum, ileum, and colon), readers recorded qualitative data (grade of nonuniform lumen opacification, types of inhomogeneous opacifications, presence of artifacts, and distribution of contrast agent) and quantitative data (CT attenuation of lumen [in Hounsfield units]). The results were compared among the three contrast agents using the Mann-Whitney U test and repeated-measures ANOVA with a post hoc Bonferroni correction. RESULTS. Fewer artifacts were detected with iohexol (4.3%) as the oral contrast agent than with diatrizoate (13.0%) and barium sulfate (14.3%) (each, p < 0.05). Barium showed a greater frequency of bowel lumen heterogeneity (388/831 segments, 47%) than iohexol (155/679, 23%) and diatrizoate (185/763, 24% segments) (p < 0.001). Barium showed higher CT attenuation than iohexol and diatrizoate in the stomach but lower CT attenuation in the ileum (each, p < 0.05). CONCLUSION. The frequency of inhomogeneous bowel opacification was lower for iohexol than for diatrizoate or barium sulfate. Barium showed the highest frequency of bowel lumen heterogeneity. The iodinated agents showed greater increases in mean CT attenuation from the proximal bowel segments to the distal bowel segments than barium sulfate.

Iopamidol as an oral contrast media for computed tomography: a taste comparison to iohexol, diatrizoate sodium, and barium sulfate

OBJECTIVES

The objective of this study is to compare the palatability of iopamidol and iohexol.

METHODS

This was a blinded and randomized trial in which fifty healthy subjects taste tested iopamidol (Isovue, Bracco Diagnostics), iohexol (Omnipaque, GE Healthcare), diatrizoate meglumine and diatrizoate sodium solution (Gastrografin, Bracco Diagnostics), and barium sulfate suspension 2.1% w/v, 2.0% w/w (READI-CAT2, E-Z-EM). Participants scored palatability on a continuous scale from 0 to 40 (0 = intolerable, 10 = unpleasant but tolerable, 20 = neutral, 30 = kind of like, 40 = strongly like).

RESULTS

Mean scores (SD/SEM) for the contrast agents (n = 50) were iopamidol = 21.0 (8.4/1.2); iohexol = 21.8 (7.1/1.0); Gastrografin = 16.8 (9.6/1.4); and barium = 23.7 (9.1/1.3). One-way ANOVA equality of means test shows rejection of the hypothesis that the means are equal (F* = 6.550, p = .000). Post hoc testing demonstrates Gastrografin to be significantly less preferred to barium (p = .000) and iohexol (p = .012). No difference was found between iopamidol and iohexol (p = .959). One-way ANOVA equality of means test of just iopamidol, iohexol, and barium does not reject the hypothesis that means are equal (F* = 1.778 and p = .174).

CONCLUSION

There is no significant difference in palatability between iopamidol and iohexol, supporting the use of iopamidol as a viable alternative to iohexol as an oral contrast agent.

Small Bowel Imaging: Computed Tomography Enterography, Magnetic Resonance Enterography, Angiography, and Nuclear Medicine

Radiology examinations play a major role in the diagnosis, management, and surveillance of small bowel diseases and are complementary to endoscopic techniques. Computed tomography enterography and magnetic resonance enterography are the cross-sectional imaging studies of choice for many small bowel diseases. Angiography still plays an important role for catheter-directed therapies. With the emergence of hybrid imaging techniques, radionuclide imaging has shown promise for the evaluation of small bowel bleeding and Crohn disease and may play a larger role in the future. This article reviews recent advances in technology, diagnosis, and therapeutic options for selected small bowel disorders.