Prospective comparison of state-of-the-art MR enterography and CT enterography in small-bowel Crohn’s disease. AJR Am J Roentgenol. 2009;193:113-121. [PMID: 19542402 DOI: 10.2214/ajr.08.2027]

Investigation of small bowel in pediatric Crohn's disease

Investigation of the small bowel has been traditionally a challenge for pediatric gastroenterologists due to its location, anatomical tortuosity, and invasiveness of the available techniques. Recently, there has been a remarkable improvement in imaging and endoscopic tools aimed at exploring successfully the small intestine in inflammatory bowel disease. The former are represented by ultrasonography (either alone or with administration of oral contrast agents) and by magnetic resonance: both have provided accurate methods to detect structural bowel changes, diminishing patient discomfort and precluding radiation hazard. The use of traditional radiologic techniques such as fluoroscopy have been markedly reduced due to radiation exposure and inability to depict transmural inflammation or extraluminal complications. Among the novel endoscopic tools, capsule endoscopy and balloon-assisted enteroscopy have tremendously opened new diagnostic and therapeutic perspectives, by allowing the direct visualization of small intestinal mucosa and, through enteroscopy, histological diagnosis as well as therapeutic interventions such as stricture dilation and bleeding treatment. These endoscopic techniques should always be preceded by imaging of the intestine in order to identify strictures. This review describes the most recent progress with the employment of novel imaging and endoscopic methodologies for investigating the small bowel in children with suspected or established Crohn's disease.

Role of computed tomography enterography/magnetic resonance enterography: is it in prime time?

Today, cross-sectional imaging modalities, such as computed tomography enterography (CTE) and magnetic resonance enterography (MRE), are particularly suited to evaluate small bowel diseases, especially Crohn's disease (CD). It is well known that CTE/MRE can provide excellent assessment of disease activity as well as the macroscopic features, extramural abnormalities, and complications of the small intestine in patients with CD. In general, CTE is considered as the first-line modality for the evaluation of suspected inflammatory bowel disease and for long-term assessment or follow-up of these patients. Because of the advantage of lack of radiation, MRE is being used more frequently, especially in children or young patients with CD.

A look into the small bowel in Crohn's disease

Crohn's disease (CD) is an inflammatory bowel disease that can affect the entire gastrointestinal tract, with the small bowel (SB) being the most commonly affected site. In some patients, refractory inflammation or chronic strictures of the SB are responsible for a debilitating course of the disease that might lead to severely reduced quality of life. Therefore, SB imaging is a crucial element in diagnosing and/or managing SB CD, and continues to evolve because of technologic advances. SB endoscopy (capsule endoscopy and device-assisted enteroscopy) and cross-sectional radiologic imaging (computed tomography enterography and magnetic resonance enterography) have become key players to diagnose and/or manage CD. In everyday practice, the choice of the imaging modalities is based on the presence and availability of the techniques and of experienced operators in each institute, clinical usefulness, safety, and cost. Here, SB endoscopy and radiologic imaging in suspected or known CD patients will be addressed and discussed.

Feasibility of using MR enterography for the assessment of terminal ileitis and inflammatory activity in children with Crohn disease

BACKGROUND AND OBJECTIVE

Radiation exposure increases cancer risk in children with Crohn disease (CD). Magnetic resonance enterography (MRE) can image the gastrointestinal tract without exposure to radiation. The aim of the present study was to determine whether our MRE protocol could diagnose terminal ileitis and the degree of inflammatory activity in children with CD.

METHODS

Retrospective review of patients 18 years of age or younger who underwent MRE for known or suspected CD from June 15, 2007 to April 1, 2010. MRE was performed with Volumen and water as oral contrast and gadolinium-based intravenous contrast. No antiperistaltic agent was used. Each MRE was compared with ileal biopsies obtained within 90 days. Severity of inflammation on MRE was scored and compared with the Pediatric Crohn Disease Activity Index (PCDAI).

RESULTS

Seventy-two patients underwent 80 MREs during the study period. Forty-two of the 72 patients (58.3%) underwent colonoscopy within 90 days of MRE, and the terminal ileum was intubated in 33. Compared with histology, MRE had a sensitivity of 71.4% and a specificity of 100% for terminal ileitis. The positive and negative predictive values were 100% and 70%, respectively. PCDAI was calculated in 39 of the 72 patients (54.2%) and had a statistically significant positive correlation with MRE score of 0.37 (P = 0.020426).

CONCLUSIONS

In children with known or suspected CD, our MRE protocol has a high specificity and positive predictive value for terminal ileitis. Severity of inflammation on MRE had a statistically significant positive correlation with PCDAI.

Cost-effectiveness of imaging strategies to reduce radiation-induced cancer risk in Crohn's disease

BACKGROUND

The aim was to examine the cost-effectiveness of magnetic resonance enterography (MRE) compared with computed tomography enterography (CTE) for routine imaging of small bowel Crohn's disease (CD) patients to reduce patients' life-time radiation-induced cancer risk.

METHODS

We developed a Markov model to compare the lifetime costs, benefits (measured in quality-adjusted life-years [QALYs] of survival and cancers averted) and cost-effectiveness of using MRE rather than CTE for routine disease monitoring in hypothetical cohorts of 100,000 20-year-old patients with CD. We assumed each CT radiation exposure conferred an incremental annual risk of developing cancer using the linear, no-threshold model.

RESULTS

In the base case of 16 mSv per CTE, we estimated that radiation from CTE resulted in 1,206 to 20,146 additional cancers depending on the frequency of patient monitoring. Compared to using CTE only, using MRE until age 30 and CTE thereafter resulted in incremental cost-effectiveness ratios (ICERs) between $37,538 and $41,031 per life-year (LY) gained and between $52,969 and $57,772 per quality-adjusted life-year (QALY) gained. Using MRE until age 50 resulted in ICERs between $58,022 and $62,648 per LY gained and between $84,250 and $90,982 per QALY gained. In a threshold analysis, any use of MRE had an ICER of greater than $100,000 per QALY gained when CT radiation doses are less than 6.0 mSv per CTE exam.

CONCLUSIONS

MRE is likely cost-effective compared to CTE in patients younger than age 50. Low-dose CTE may be an alternative cost-effective choice in the future.

Inflammatory bowel disease in children and adolescents: assessing the diagnostic performance and interreader agreement of magnetic resonance enterography compared to histopathology

RATIONALE AND OBJECTIVES

The purpose of this study was to determine the accuracy of magnetic resonance enterography (MRE) compared to histopathology in the evaluation of pediatric inflammatory bowel disease and to assess interreader reliability for image interpretation.

MATERIALS AND METHODS

All magnetic resonance enterography studies performed for known or suspected inflammatory bowel disease between July 2009 and July 2010 were retrospectively reviewed by two pediatric radiologists. Exams were evaluated for signs of enteric inflammation and extraenteric disease. A five-point, Likert-type scale was used to assess the overall likelihood of active inflammation, with scores ≥ 3 considered positive. Cohen's κ coefficient was calculated to assess interreader agreement. A subset of patients who had undergone ileocolonoscopy or surgery with confirmed histopathology within 45 days of MRE were used to assess the accuracy of MRE for detecting active inflammation in the terminal ileum and large bowel.

RESULTS

A total of 91 magnetic resonance enterography studies were reviewed. Of these, 45 had comparison histopathology within 45 days. The overall sensitivity of MRE for detecting active inflammation compared to ileocolonoscopy was 92% for both readers, while specificity was 100% for reader 1 and 75% for reader 2. Of the individual parameters evaluated, mucosal hyperenhancement and bowel wall thickening were the most sensitive indicators of active inflammation, each having sensitivity of 86% and specificity of 88%. Cohen's κ coefficient was 0.59, indicating moderate agreement between the readers.

CONCLUSIONS

MRE has high overall diagnostic accuracy for detecting active bowel inflammation in pediatric patients compared to ileocolonoscopy and demonstrates moderate interreader reliability.

CT enterography: review of technique and practical tips

CT enterography is a new non-invasive imaging technique that offers superior small bowel visualisation compared with standard abdomino-pelvic CT, and provides complementary diagnostic information to capsule endoscopy and MRI enterography. CT enterography is well tolerated by patients and enables accurate, efficient assessment of pathology arising from the small bowel wall or surrounding organs. This article reviews the clinical role of CT enterography, and offers practical tips for optimising technique and accurate interpretation.

Health supervision in the management of children and adolescents with IBD: NASPGHAN recommendations

Ulcerative colitis (UC) and Crohn disease (CD), collectively referred to as inflammatory bowel disease (IBD), are chronic inflammatory disorders that can affect the gastrointestinal tract of children and adults. Like other autoimmune processes, the cause(s) of these disorders remain unknown but likely involves some interplay between genetic vulnerability and environmental factors. Children, in particular with UC or CD, can present to their primary care providers with similar symptoms, including abdominal pain, diarrhea, weight loss, and bloody stool. Although UC and CD are more predominant in adults, epidemiologic studies have demonstrated that a significant percentage of these patients were diagnosed during childhood. The chronic nature of the inflammatory process observed in these children and the waxing and waning nature of their clinical symptoms can be especially disruptive to their physical, social, and academic development. As such, physicians caring for children must consider these diseases when evaluating patients with compatible symptoms. Recent research efforts have made available a variety of more specific and effective pharmacologic agents and improved endoscopic and radiologic assessment tools to assist clinicians in the diagnosis and interval assessment of their patients with IBD; however, as the level of complexity of these interventions has increased, so too has the need for practitioners to become familiar with a wider array of treatments and the risks and benefits of particular diagnostic testing. Nonetheless, in most cases, and especially when frequent visits to subspecialty referral centers are not geographically feasible, primary care providers can be active participants in the management of their pediatric patients with IBD. The goal of this article is to educate and assist pediatricians and adult gastroenterology physicians caring for children with IBD, and in doing so, help to develop more collaborative care plans between primary care and subspecialty providers.

Imaging for luminal disease and complications: CT enterography, MR enterography, small-bowel follow-through, and ultrasound

The advent of cross-sectional enterography has revolutionized small-bowel imaging, providing comprehensive, reproducible evaluation of CD and its complications. Continued collaboration between radiologists and gastroenterologists is critical to ensure further progress toward the common goals of classifying disease activity, predicting response to treatment, and appropriate triage to medical versus surgical therapy.

Obscure and occult gastrointestinal bleeding: comparison of different imaging modalities

Patients with persistent, recurrent, or intermittent bleeding from the gastrointestinal (GI) tract for which no definite cause has been identified by initial esophagogastroduodenoscopy, colonoscopy, or conventional radiologic evaluation are considered to have an obscure GI bleeding (OGIB). The diagnosis and management of patients with OGIB is challenging, often requiring extensive and expensive workups. The main objective is the identification of the etiology and site of bleeding, which should be as rapidly accomplished as possible, in order to establish the most appropriate therapy. The introduction of capsule endoscopy and double balloon enteroscopy and the recent improvements in CT and MRI techniques have revolutionized the approach to patients with OGIB, allowing the visualization of the entire GI tract, particularly the small bowel, until now considered as the "dark continent" . In this article we review and compare the radiologic and endoscopic examinations currently used in occult and OGIB, focusing on diagnostic patterns, pitfalls, strengths, weaknesses, and value in patients' management.

Accuracy of imaging for predicting operative approach in Crohn's disease

Background

The aim of this study was to assess the accuracy of preoperative imaging in detecting the extent of disease and predicting the operative approach in patients with Crohn's disease.

Methods

Patients with Crohn's disease who were scheduled to undergo operation were evaluated before operation using computed tomography enteroclysis (CTE) and magnetic resonance enterography (MRE). Preoperative imaging findings were correlated with intraoperative and pathological findings to estimate the capabilities of preoperative imaging in detecting lesions due to Crohn's disease. The operative approach determined before surgery was compared with the procedure actually performed, which was based on intraoperative findings.

Results

Fifty-two patients with Crohn's disease were studied; 26 were evaluated before surgery with CTE and 26 with MRE. Eighty-nine lesions due to Crohn's disease were confirmed surgically (60 small bowel stenoses, 21 fistulas and 8 abscesses). CTE confirmed the presence of 38 of 41 lesions (sensitivity 93 per cent) and MRE 48 of 48 lesions (sensitivity 100 per cent); a correct estimation of the disease with an exact prediction of the operative approach was obtained in 49 (94 per cent) of 52 patients. Discrepant findings between preoperative imaging and operative findings were observed in three patients (6 per cent), who had CTE.

Conclusion

Preoperative imaging using CTE or MRE is highly accurate for assessing Crohn's disease lesions before operation, allowing correct prediction of the operative approach.

Computed tomographic enteroclysis with air and virtual enteroscopy: protocol and feasibility for small bowel evaluation

BACKGROUND AND AIMS

We describe our optimized protocol for computed tomographic enteroclysis using air as the contrast material and report an early assessment of its clinical performance.

METHODS

Thirty-one examinations of computed tomographic enteroclysis with air were performed in 30 patients in our hospital from September 2008 to September 2010. The volume of injected air and intra-intestinal pressure were monitored in 16 cases. The data were reviewed for ratios of successful whole small bowel depictions out of the total number of examinations for patients without stenosis. Efforts were made to confirm depicted abnormal findings when possible by other imaging techniques, intra-operative findings, histopathological findings, and subsequent history.

RESULTS

The injected air volume and final intra-intestinal pressure were 2925 ± 686 ml and 24.5 ± 7.1cm H₂O in cases without stenosis. In 19 examinations with anterograde air injection for patients without stenosis, whole small bowel depiction was achieved in 16 (84.2%). Computed tomographic enteroclysis with air was useful for detecting strictures (in Crohn's disease, malignant lymphoma, metastatic carcinoma), Meckel's diverticulum, and for excluding other obstructive conditions in ileus.

CONCLUSIONS

Computed tomographic enteroclysis with air has a potential to enable the exploration of the whole small bowel, thereby providing information of small bowel lesions that complements other techniques.

MR enterography correlates highly with colonoscopy and histology for both distal ileal and colonic Crohn's disease in 310 patients

BACKGROUND AND AIMS

To evaluate the efficacy of MR enterography (MRE) in patients with known or suspected Crohn's disease without the use of anti-peristaltic pharmacologic agents compared to colonoscopy and histology.

METHODS

A retrospective review of 850 consecutive patients who underwent routine MRE to evaluate known or suspected Crohn's disease was performed. Of these, 310 patients also underwent colonoscopy with biopsy(s) within 90 days. The results of the MRE were compared to the colonoscopy and pathology reports to determine the presence or absence of disease in evaluable bowel segments. Individual imaging parameters (including wall thickening, enhancement, T2 signal, mesenteric vascular prominence and adenopathy) were also separately analyzed to determine their independent predictive value.

RESULTS

In 310 patients, the overall sensitivity and specificity of MRE (using endoscopy as a gold standard) were 85% and 80% respectively (kappa=0.65). The sensitivity of MRE for detection of pathologically severe disease was 87% in the terminal ileum (TI) and 88% in the colon. In the subset of 162 patients who underwent colonoscopy within 30 days of MRE, the overall sensitivity remained 85% but the specificity increased to 85% (kappa=0.69). Wall thickening and abnormal enhancement were sensitive indicators of Crohn's disease (75% and 78%), while abnormal T2 signal, mesenteric vascular prominence and adenopathy were specific (86%, 91% and 93%).

CONCLUSION

MRE compares favorably to colonoscopy for evaluation of known or suspected Crohn's disease noninvasively and without the exposure to ionizing radiation associated with CT enterography (CTE).

Evaluation of inflammatory activity in Crohn’s disease and ulcerative colitis

Crohn’s disease and ulcerative colitis evolve with a relapsing and remitting course. Determination of inflammatory state is crucial for the assessment of disease activity and for tailoring therapy. However, no simple diagnostic test for monitoring intestinal inflammation is available. Noninvasive markers give only indirect assessments of disease activity. Histopathological or endoscopical examinations accurately assess inflammatory activity, but they are invasive, time consuming and expensive and therefore are unsuitable for routine use. Imaging procedures are not applicable for ulcerative colitis. The usefulness of ultrasound and Doppler imaging in assessing disease activity is still a matter of discussion for Crohn’s disease, and an increased interest in computed tomography enterograph (CTE) has been seen, mainly because it can delineate the extent and severity of bowel wall inflammation, besides detecting extraluminal findings. Until now, the available data concerning the accuracy of magnetic resonance enterography in detecting disease activity is less than CTE. Due to this, clinical activity indices are still commonly used for both diseases.

Diagnostic workup of paediatric patients with inflammatory bowel disease in Europe: results of a 5-year audit of the EUROKIDS registry

OBJECTIVE

In 2005, the Inflammatory Bowel Disease (IBD) Working Group of the European Society for Pediatric Gastroenterology, Hepatology, and Nutrition published consensus guidelines on the diagnostic workup of paediatric IBD, the Porto criteria. According to these guidelines, children suspected of having IBD should undergo an oesophagogastroduodenoscopy (OGD), ileocolonoscopy, and (except in cases of definitive ulcerative colitis) adequate imaging of the small bowel. To audit and evaluate the diagnostic workup of paediatric patients with IBD in Europe, the Working Group created EUROKIDS, a prospective, Web-based registry of newly diagnosed paediatric patients with IBD.

METHODS

Patients with IBD (ages 0-18 years) were registered in 44 centres in 18 countries. Data on diagnostic workup were analysed according to the year of diagnosis, type of IBD, and centre size. Diagnostic yield of OGD and ileal intubation were evaluated.

RESULTS

Between 2004 and 2009, 2087 newly diagnosed patients were correctly registered. Both OGD and ileocolonoscopy had been performed in 64% of all of the patients and increased significantly from year 1 (52 %) to 5 (71%, P  <  0.001). Small-bowel follow-through use decreased during the years (year 1 n = 213, year 5 n = 108; P < 0.001), whereas magnetic resonance imaging use increased (year 1 n  = 25, year 5 n  = 171; P < 0.001). Patients diagnosed as having Crohn disease (CD, 59%) and ulcerative colitis (58%) were more likely to have had a complete diagnostic workup than patients diagnosed as having IBD unclassified (45%). In CD, the diagnostic yield of OGD was 7.5% and the yield of ileal intubation was 13%.

CONCLUSIONS

The quality of diagnostic workup in paediatric patients with IBD increased steadily between 2004 and 2009. Small-bowel imaging by magnetic resonance imaging superseded the use of small-bowel follow-through. OGD and ileal intubation contributed to a definitive diagnosis of CD.

MR enterography of extraluminal manifestations of inflammatory bowel disease in children and adolescents: moving beyond the bowel wall

OBJECTIVE

The purpose of this review is to describe the extraintestinal manifestations of inflammatory bowel disease at MR enterography of children and adolescents.

CONCLUSION

MR enterography excellently depicts a variety of extraluminal manifestations of inflammatory bowel disease affecting a variety of organ systems. Because many of these findings can be clinically important, it is critical that radiologists look beyond the bowel wall when interpreting these images.

Benefit of computed tomography enterography in Crohn's disease: effects on patient management and physician level of confidence

BACKGROUND

Computed tomographic enterography (CTE) has been shown to have a high sensitivity and specificity for active small bowel inflammation. There are only sparse data on the effect of CTE results on Crohn's disease (CD) patient care.

METHODS

We prospectively assessed 273 patients with established or suspected CD undergoing a clinically indicated CTE. Providers were asked to complete pre- and postimaging questionnaires regarding proposed clinical management plans and physician level of confidence (LOC) for the presence or absence of active small bowel disease, fistula(s), abscess(es), or stricturing disease. Correlative clinical, serologic, and histologic data were recorded. Following revelation of CTE results, providers were questioned if CTE altered their management plans, and whether LOC changes were due to CTE findings (on a 5-point scale).

RESULTS

CTE altered management plans in 139 cases (51%). CTE changed management in 70 (48%) of those with established disease, prompting medication changes in 35 (24%). Management changes were made post-CTE in 69 (54%) of those with suspected CD, predominantly due to excluding CD (36%). CTE-perceived changes in management were independent of clinical, serologic, and histologic findings (P < 0.0001). Clinically meaningful LOC changes (2 or more points) were observed in 212 (78%).

CONCLUSIONS

CTE is a clinically useful examination, altering management plans in nearly half of patients with CD, while increasing physician LOC for the detection of small bowel inflammation and penetrating disease. These findings further support the use of CTE in CD management algorithms.

Advances in small bowel imaging

The small intestine has been difficult to examine by traditional endoscopic and radiologic techniques. Within the past 10 years, advances have led to an explosion of technologies that facilitate examination of the entire small intestine. Wireless video capsule endoscopy, deep enteroscopy using balloon-assisted or spiral techniques, computer tomography (CT) and magnetic resonance (MR) enterography have facilitated the diagnosis, monitoring, and management of patients with small intestinal diseases. These technologies are complementary, each with its advantages and limitations. Capsule endoscopy provides a detailed view of the mucosal surface and has excellent patient acceptance, but does not allow therapeutics. Deep enteroscopy allows careful inspection of the mucosa and therapeutics, but is time consuming and invasive. Enterography (CT or MR) allows examination of the small bowel wall and surrounding structures. The initial best test for detecting small intestinal disease depends on clinical presentation and an astute differential diagnosis.

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.

Diagnostic accuracies of MR enterography and CT enterography in symptomatic Crohn's disease

OBJECTIVE

In patients, with symptomatic Crohn's disease (CD), valid information about the presence or absence of small bowel disease activity and stenosis is clinically important. Such information supports decisions about medical or surgical therapy and can be obtained with MR enterography (MRE) or CT enterography (CTE).

MATERIALS AND METHODS

A total of 50 patients with symptomatic pre-existing CD and a demand for small bowel imaging to support changes in treatment strategy were included in this prospective and blinded study. MRE and CTE were performed on the same day in alternating order and subsequently compared with the gold standard: pre-defined lesions at ileoscopy (n = 30) or surgery with (n = 12) or without (n = 3) intra-operative enteroscopy.

RESULTS

A total of 35 patients had active small bowel CD (jejunum 0, ileum 1, (neo)-terminal ileum 34) and 20 had small bowel stenosis. The sensitivity and specificity of MRE for detection of small bowel CD was 74% and 80% compared to 83% and 70% with CTE (p ≥ 0.5). MRE and CTE detected small bowel stenosis with 55% and 70% sensitivities, respectively (p = 0.3) and 92% specificities.

CONCLUSIONS

MRE and CTE have comparable diagnostic accuracies for detection of small bowel CD and stenosis. In symptomatic patients with CD and high disease prevalence, positive predictive values are favorable but negative predictive values are low. Consequently, MRE and CTE can be relied upon, if a positive result is obtained whereas a negative enterography should be interpreted with caution.

MRI in Crohn's disease--current and future clinical applications

Crohn's disease is a chronic, disabling disease that, over time, can lead to irreversible bowel damage. MRI can be used to diagnose and assess the activity, severity and complications of Crohn's disease; however, the role of MRI in therapeutic monitoring of changes in disease-related intestinal damage is still to be defined. Objective, validated MRI-based scores have been developed to assess the activity of Crohn's disease; these indices are based on the extent and severity of intestinal inflammation, postoperative recurrence and perianal disease. MRI is accurate, safe, reproducible and can allow repeated evaluations of patients without radiation exposure. Evidence that MRI might be valuable in the therapeutic monitoring of patients with Crohn's disease is increasing and, in combination with endoscopy and surgical history, this imaging technique could enable clinicians to assess Crohn's-disease-related intestinal damage. MRI could, therefore, have a crucial role in a future 'damage-driven' treatment paradigm--in which imaging is used to monitor intestinal damage and medication use is targeted to prevent the accumulation of further damage. This damage-driven therapeutic approach could potentially change the course of Crohn's disease.

MRI in Crohn's disease--current and future clinical applications

Crohn's disease is a chronic, disabling disease that, over time, can lead to irreversible bowel damage. MRI can be used to diagnose and assess the activity, severity and complications of Crohn's disease; however, the role of MRI in therapeutic monitoring of changes in disease-related intestinal damage is still to be defined. Objective, validated MRI-based scores have been developed to assess the activity of Crohn's disease; these indices are based on the extent and severity of intestinal inflammation, postoperative recurrence and perianal disease. MRI is accurate, safe, reproducible and can allow repeated evaluations of patients without radiation exposure. Evidence that MRI might be valuable in the therapeutic monitoring of patients with Crohn's disease is increasing and, in combination with endoscopy and surgical history, this imaging technique could enable clinicians to assess Crohn's-disease-related intestinal damage. MRI could, therefore, have a crucial role in a future 'damage-driven' treatment paradigm--in which imaging is used to monitor intestinal damage and medication use is targeted to prevent the accumulation of further damage. This damage-driven therapeutic approach could potentially change the course of Crohn's disease.

Performance of the patency capsule compared with nonenteroclysis radiologic examinations in patients with known or suspected intestinal strictures

BACKGROUND

The patency capsule (PC) is used before capsule endoscopy (CE) in patients with known or suspected small-bowel (SB) strictures or obstruction (SBO) to avoid CE retention. False-positive PC examination results can occur in patients with delayed transit without obstruction, precluding the use of CE. Radiological tests are another option to evaluate the presence of SBO before CE.

OBJECTIVES

Comparison of the PC and radiological examinations to detect clinically significant SB strictures.

MAIN OUTCOME MEASUREMENTS

Sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the PC, and radiological tests for detecting significant strictures.

RESULTS

Forty-two patients underwent a PC study and radiological examinations. Both of the examinations showed similar sensitivity (57% vs 71%; P = 1.00) and specificity (86% vs 97%; P = .22). The receiver-operating characteristic curves evaluating combined sensitivity and specificity were also similar in both the PC and radiological examinations (0.71 vs 0.84, respectively; P = .46). Pooling results from both the PC and radiological tests had the highest sensitivity and NPV (100%, 100%). False-positive results occurred in 5 PC examinations and 1 radiological examination. The PC examination had 3 false-negative results (9%), whereas radiological tests had 2 (6%).

LIMITATIONS

Retrospective study.

CONCLUSIONS

The NPV for the PC and radiological tests were not significantly different, suggesting that if findings on either test are negative before CE, the patient will most likely pass the capsule without incident. Radiological tests can be used to minimize PC study false-positive results by confirming or excluding the presence of a significant stricture suspected by the PC and to localize the PC if passage is delayed.

Magnetic resonance enterography: safe and effective imaging for stricturing Crohn's disease

BACKGROUND

Symptomatic Crohn's disease (CD) patients often undergo diagnostic imaging studies for evaluation of disease activity or complications including bowel strictures and obstruction. Magnetic resonance enterography (MRE) provides information regarding disease activity, chronicity, and stricture formation without using ionizing radiation.

AIM

Examine the use of MRE among CD patients presenting with symptoms suggesting obstruction in a tertiary care practice setting.

METHODS

We performed a retrospective study of all CD patients undergoing MRE at a tertiary IBD referral center over a 3-year study period including a subgroup analysis of patients presenting obstructive symptoms. Positive and negative findings from MRE were correlated with medical and surgical decision outcomes over the subsequent 90-day period.

RESULTS

In the study, 119 CD patients underwent 133 MRE scans, including 40 scans on individuals presenting with obstructive symptoms. Positive findings of CD including active inflammation, stricturing, and penetrating disease were more frequent in MREs ordered to evaluate obstructive symptoms (87.5%) compared other indications (58.1%, p = 0.001). In patients presenting with obstructive symptoms, MRE findings assisted in directing a change of clinical management towards escalation of medical therapy in 55% and surgery in 32.5%. Review of surgical resection specimens corroborated MRE findings of disease activity and fibrosis in 92% of cases going to surgery.

CONCLUSIONS

In practice-based use at a tertiary IBD referral center, MRE provided an effective, radiation-free alternative to computed tomography by providing valuable diagnostic information for evaluating and directing care in Crohn's disease, particularly for patients presenting with obstructive symptoms.

Gastroenterology review and perspective: the role of cross-sectional imaging in evaluating bowel damage in Crohn disease

OBJECTIVE

This article will review the performance and limitations of cross-sectional imaging methods to detect and display critical features of Crohn disease (CD)-related bowel damage, including stenosis and penetrating complications (i.e., fistula, abscess). International efforts to incorporate cross-sectional imaging findings along with endoscopic and surgical findings to create a global bowel damage score over the length of the gastrointestinal tract are summarized along with the rationale for these efforts.

CONCLUSION

The first digestive damage score, the Lémann score, will incorporate surgical history, endoscopic findings, and imaging findings of stenosis and penetrating complications to provide a global assessment of CD-related destruction of the gastrointestinal tract. It is anticipated that the score will permit better understanding of the impact of modern therapeutics on the natural history of CD. Because CT is a technique that involves ionizing radiation and accuracy of ultrasound is highly related to CD location, MRI is proposed as first choice for nonemergent follow-up of CD patients.

Prospective evaluation of MR enterography as the primary imaging modality for pediatric Crohn disease assessment

OBJECTIVE

The objectives of this study were prospective evaluation of MR enterographic accuracy for detecting Crohn disease imaging features in pediatric patients, compared with a CT reference standard, as well as determination of MR enterographic accuracy for detecting active bowel inflammation and fibrosis using a histologic reference standard.

SUBJECTS AND METHODS

The study group for this blinded prospective study included 21 pediatric subjects with known Crohn disease scheduled for clinical CT and histologic bowel sampling for symptomatic exacerbation. All subjects and their parents gave informed consent to also undergo MR enterography. CT and MR enterography examinations were independently reviewed by two radiologists and were scored for Crohn disease features. All bowel histology specimens were reviewed by a single pathologist for the presence of active mucosal inflammation and mural fibrosis, followed by correlation of imaging and histologic findings.

RESULTS

All 21 subjects underwent MR enterography and histologic sampling, 18 of whom also underwent CT. MR enterography had high sensitivity for detecting Crohn disease imaging features (e.g., bowel wall thickening, mesenteric inflammation, lymphadenopathy, fistula, and abscess) compared with CT, with individual sensitivity values ranging from 85.1% to 100%. Of a total of 53 abnormal bowel segments with correlation of MRI and histologic findings, MR enterography showed 86.7% accuracy (90.0% sensitivity and 82.6% specificity) for detecting active inflammation (p < 0.001). The accuracy of MR enterography for detecting mural fibrosis overall was 64.9%, compared with histology, but increased to 83.3% (p < 0.05) for detecting fibrosis without superimposed active inflammation.

CONCLUSION

MR enterography can substitute for CT as the first-line imaging modality in pediatric patients with Crohn disease, on the basis of its ability to detect intestinal pathologic abnormalities in both small and large bowel as well as extraintestinal disease manifestations. Additionally, MR enterography provides an accurate noninvasive assessment of Crohn disease activity and mural fibrosis and can aid in formulating treatment strategies for symptomatic patients and assessing therapy response.

A prospective comparison of standard-dose CT enterography and 50% reduced-dose CT enterography with and without noise reduction for evaluating Crohn disease

OBJECTIVE

The purpose of this study was to prospectively compare standard-dose CT enterography (CTE) and 50% reduced-dose CTE, obtained with and without an image noise reduction method, in the evaluation of Crohn disease.

SUBJECTS AND METHODS

Ninety-two patients (69 men and 23 women; mean age [± SD], 31.2 ± 9.5 years) with Crohn disease underwent CTE. Using a dual-source scanner equipped with a proprietary noise reduction method (iterative reconstruction in image space [IRIS]), three sets of CTE images were obtained: standard-dose filtered back projection (FBP) (i.e., weighted FBP), low-dose (i.e., 50% reduction) FBP, and low-dose IRIS CTE. Image noise was measured. Two independent radiologists evaluated subjective image quality (1 [worst] to 4 [best]) and findings of active Crohn disease in the terminal small-bowel segment, including mural hyperenhancement, thickening and stratification, comb sign, and increased perienteric fat attenuation (1 [definitely absent] to 5 [definitely present]).

RESULTS

The mean (± SD) volume CT dose index (CTDI(vol)) was 7.0 ± 0.9 mGy and 3.5 ± 0.5 mGy for standard-dose and low-dose CTE examinations, respectively. The mean (± SD) image noise for standard-dose FBP, low-dose FBP, and low-dose IRIS CTE was 10.6 ± 1.7 HU, 13.9 ± 2.1 HU, and 9.7 ± 1.7 HU, respectively (p < 0.001 for all comparisons). Both assessors found that image quality was poorer with low-dose (mean grade (± SD), 2.3 ± 0.4-2.7 ± 0.5) than in standard-dose (3 ± 0) CTE (p < 0.01), and one found that image quality was poorer with low-dose IRIS (2.3 ± 0.4) than with low-dose FBP (2.7 ± 0.5) CTE (p < 0.01). Low-dose (with or without IRIS) and standard-dose CTE showed ≥ 85% agreement (one-sided 95% CI ≥ 77%) in interpretation of bowel findings.

CONCLUSION

Low-dose CTE using 50% reduced-dose performed similarly to standard-dose CTE in identifying findings of enteric inflammation of Crohn disease. Although a noise reduction method markedly reduced image noise in half-dose examinations, its effect on image quality was not as great and was reader dependent.

Newer CT applications and their alternatives: what is appropriate in children?

Innovations in image acquisition and reconstruction technologies have greatly expanded the range of CT applications available in the routine clinical setting. CT images of sub-millimeter resolution can now be acquired of entire body regions in a few seconds or even sub-second time, allowing depiction of fine anatomical detail uncompromised by motion artifact. With sophisticated visualization software, image data can be processed into multiplanar, volume-rendered, cine and other formats to better display anatomical abnormalities and facilitate newer applications such as CT angiography, enterography, urography, tracheobronchography and cardiac CT. Newer applications including dual-energy material decomposition CT are furthering the transition of CT from a purely morphological to a combined anatomical, functional and metabolic imaging technique. These newer applications have largely been pioneered in adult populations, and heightened concern of the risk of carcinogenesis from ionizing radiation tempers dissemination of their use in children. Similar information can often be gleaned from alternative imaging modalities without ionizing radiation exposure, such as MRI and US, and what is most appropriate in children will depend on relative diagnostic efficacy, cost, availability and local expertise.

Noninvasive imaging of the small bowel in Crohn's disease: the final frontier

The substantial morbidity and mortality associated with Crohn's disease underlines the importance of accurate assessment at presentation, during follow-up, when investigating complications, and when evaluating the response to therapeutic interventions. Accurate methods are required to quantify the severity and extent of disease.

MRI in patients with inflammatory bowel disease

Inflammatory bowel disease (IBD) affects ≈1.4 million people in North America and, because of its typical early age of onset and episodic disease course, IBD patients often undergo numerous imaging studies over the course of their lifetimes. Computed tomography (CT) has become the standard imaging modality for assessment of IBD patients because of its widespread availability, rapid image acquisition, and ability to evaluate intraluminal and extraluminal disease. However, repetitive CT imaging has been associated with a significant ionizing radiation risk to patients, making MRI an appealing alternative IBD imaging modality. Pelvic MRI is currently the imaging gold standard for detecting perianal disease, while recent studies indicate that MRI bowel-directed techniques (enteroclysis, enterography, colonography) can accurately evaluate bowel inflammation in IBD. With recent technical innovations leading to faster and higher resolution body MRI, the role of MRI in IBD evaluation is likely to continue to expand. Future applications include surveillance imaging, detection of mural fibrosis, and early assessment of therapy response.

Active Crohn's disease in the small bowel: evaluation by diffusion weighted imaging and quantitative dynamic contrast enhanced MR imaging

PURPOSE

To determine relative diagnostic value of MR diffusion and perfusion parameters in detection of active small bowel inflammation in patients with Crohn's disease (CD).

MATERIALS AND METHODS

We reviewed 18 patients with active CD of terminal ileum (TI) who underwent MR enterography (MRE; including dynamic contrast enhanced MRI and diffusion-weighted MRI). Conventional MRI findings of TI were recorded. Regions of interest were drawn over TI and normal ileum to calculate apparent diffusion coefficient (ADC), the volume transfer constant (K(trans)) and the contrast media distribution volume (v(e)). Receiver operating characteristic analysis was used to determine their diagnostic performance.

RESULTS

Among conventional MR findings, mural thickening and increased enhancement were present in all actively inflamed small bowel. K(trans), v(e), and ADC values differed significantly between actively inflamed TI and normal ileum (0.92 s(-1) versus 0.36 s(-1); 0.31 versus 0.15 ± 0.08; 0.00198 mm(2)/s versus 0.00311 mm(2)/s; P < 0.001). Area under the curve (AUC) for K(trans), v(e), and ADC values ranged from 0.88 to 0.92 for detection of active inflammation. Combining K(trans) and ADC data provided an AUC value of 0.95.

CONCLUSION

Dynamic contrast-enhanced MRI (DCE-MRI) and diffusion-weighted imaging (DWI) provide quantitative measures of small bowel inflammation that can differentiate actively inflamed small bowel segments from normal small bowel in CD. DWI provides better sensitivity compared with DCE-MRI and combination of ADC and K(trans) parameters for analysis can potentially improve specificity.

Magnetic resonance imaging for evaluation of Crohn's disease: validation of parameters of severity and quantitative index of activity

BACKGROUND

The use of magnetic resonance imaging (MRI) for assessment of Crohn's disease (CD) is expanding. The aim of this study is to define and provide an external validation of the MRI predictors of active CD, severe CD, and a quantitative Magnetic Resonance Index of Activity (MaRIA).

METHODS

In all, 48 patients with clinically active (n = 29) or inactive (n = 19) CD underwent ileocolonoscopy (reference standard) and MRI. T2-weighted and pre- and postcontrast-enhanced T1-weighted sequences were acquired. Endoscopic activity was evaluated by the Crohn's Disease Endoscopic Index of Severity (CDEIS), and also classified as absent, mild (inflammation without ulcers), or severe (presence of ulceration).

RESULTS

In complete agreement with a previous derivation study, independent predictors of disease severity using CDEIS as a reference were wall thickness, relative contrast enhancement (RCE), presence of edema, and ulcers on MRI. Estimation of activity in each segment using this regression model, or another with simplified coefficients (MaRIA(S) = 1.5*wall thickness + 0.02*RCE + 5*edema + 10*ulceration) correlated with CDEIS (r = 0.798, P< 0.001; r = 0.80 P < 0.001, respectively). In the validation cohort both indexes had a high and equal accuracy for diagnosis of active disease: receiver operator characteristic (ROC) area 0.93, sensitivity 0.87, specificity 0.87 using a cutoff point ≥ 7, and for diagnosis of severe disease: ROC area 0.96, sensitivity 0.92, specificity 0.92 using a cutoff point ≥ 11. The total of segment values (MaRIA(T)) correlated with global CDEIS (r = 0.83, P< 0.001).

CONCLUSIONS

The MRI variables that should be evaluated in clinical practice to diagnose active CD and severe CD are validated, as well as the quantitative index of activity for use in research studies.

Computed tomography enterography detects intestinal wall changes and effects of treatment in patients with Crohn's disease

BACKGROUND & AIMS

The use of computed tomography enterography (CTE) in patients with Crohn's disease has increased. However, there is little data available on how radiologic parameters of active disease change during treatment with infliximab and whether these changes correspond to symptoms, serum biomarkers, or endoscopic appearance.

METHODS

We performed a retrospective study of patients with Crohn's disease who had undergone serial CTE imaging while receiving infliximab. Lesions were defined as improved if their enhancement or length decreased without worsening of other parameters. Patients were grouped as responders (all lesions improved), partial responders (some lesions improved), and nonresponders (worsening or no changes in all lesions). Of the 63 patients identified (47% female), the median age was 37.7 years, the median disease duration was 7.6 years, and the median time between initial and first follow-up CTE was 356 days (interquartile range, 215-630).

RESULTS

Of 105 lesions, 52 (49.5%) improved, 11 (10.5%) remained unchanged, and 42 (40.0%) worsened. Per patient, 28 (44.4%) were responders, 12 (19.0%) were partial responders, and 23 (36.5%) were nonresponders. The radiologic response had poor-to-fair agreement with symptoms, endoscopic appearance, and levels of C-reactive protein at time of second CTE (κ = 0.26, 0.07, and 0.30 respectively).

CONCLUSIONS

Radiologic improvement was observed in 63.4% of patients with Crohn's disease who received infliximab therapy, despite a study design that was likely biased toward nonresponders. Radiologic response was not in good agreement with clinical symptoms, serum biomarkers, or endoscopic appearance; CTE might be used as a complementary approach to identify mural healing or inflammation not detected by other methods.

Systematic review: the use of ultrasonography, computed tomography and magnetic resonance imaging for the diagnosis, assessment of activity and abdominal complications of Crohn's disease

BACKGROUND

Cross-sectional imaging techniques, including ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI), are increasingly used for evaluation of Crohn's disease (CD). Aim  To perform an assessment of the diagnostic accuracy of cross-sectional imaging techniques for diagnosis of CD, evaluation of disease extension and activity and diagnosis of complications, and to provide recommendations for their optimal use.

METHODS

Relevant publications were identified by literature search and selected based on predefined quality parameters, including a prospective design, sample size and reference standard. A total of 68 publications were chosen.

RESULTS

Ultrasonography is an accurate technique for diagnosis of suspected CD and for evaluation of disease activity (sensitivity 0.84, specificity 0.92), is widely available and non-invasive, but its accuracy is lower for disease proximal to the terminal ileum. MRI has a high diagnostic accuracy for the diagnosis of suspected CD and for evaluation of disease extension and activity (sensitivity 0.93, specificity 0.90), and is less dependent on the examiner and disease location compared with US. CT has a similar accuracy to MRI for assessment of disease extension and activity. The three techniques have a high accuracy for identification of fistulas, abscesses and stenosis (sensitivities and specificities >0.80), although US has false positive results for abscesses. As a result of the lack of radiation, US or MRI should be preferred over CT, particularly in young patients.

CONCLUSIONS

Cross-sectional imaging techniques have a high accuracy for evaluation of suspected and established CD, reliably measure disease severity and complications; they may offer the possibility to monitor disease progression.

Detection of Crohn's disease: Comparison of CT and MR enterography without anti-peristaltic agents performed on the same day

OBJECTIVE

To directly compare CT enterography (CTE) and MR enterography (MRE) without antiperistaltic agents.

MATERIALS/METHODS

26 patients referred for CTE underwent CTE immediately followed by MRE without use of an anti-peristaltic agent. Each study was evaluated on a 10 point scale for exam quality, level of diagnostic confidence, and presence of Crohn's disease. Kappa analysis was performed to determine the degree of agreement between the CTE and MRE of each patient.

RESULTS

25 patients completed the MRE. The quality of the CTEs was judged as excellent by both readers (reader 1=average 9.5/10, reader 2=average 9.1/10). The quality of the MREs was ranked lower than the CTEs by both readers (reader 1=average 8.9/10, reader 2=average 7.2/10), which was statistically significant (p<0.05). The level of confidence in interpretation was not significantly different between CTE and MRE for reader 1 or 2 (p=0.3). There was substantial agreement between readers for the presence or absence of Crohn's disease on both CTE (kappa=0.75) and MRE (kappa=0.67).

CONCLUSION

MR enterography without anti-peristaltic agents results in high diagnostic confidence and excellent agreement for the presence of Crohn's disease.

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.

Interobserver and intermodality agreement for detection of small bowel Crohn's disease with MR enterography and CT enterography

BACKGROUND

Magnetic resonance enterography (MRE) and computed tomography enterography (CTE) visualizes small bowel Crohn's disease (CD) and its complications with high accuracy. The aim of this study was to determine the interobserver and intermodality agreement for detection of small bowel CD.

METHODS

Fifty patients with suspected or known CD were included in the study and all patients underwent MRE and CTE on the same day. Four radiologists with experience in MRE and CTE techniques participated. Observers were blind to patient histories, results of ileocolonoscopies, and other small bowel examinations. Readers assessed the image quality, the presence of small bowel CD, and seven findings consistent with CD.

RESULTS

The image quality was better with CTE than MRE (P < 0.001) but the diagnostic yields were comparable (P = 0.4). For detection of small bowel CD, the interobserver agreement was substantial in CTE (κ = 0.64) and moderate in MRE (κ = 0.48). The intermodality agreement was fair to substantial (κ = 0.40-0.64) for different observers. Two abscesses were detected and confirmed at subsequent surgery. One abscess was not detected with MRE and only recorded by two observers in CTE. A total of 10 fistulas were detected: three were confirmed at subsequent surgery and four were false-positive findings.

CONCLUSIONS

MRE and CTE have comparable diagnostic yields in patients with suspected or known CD. However, CTE provides better image quality and interobserver agreement. In a substantial number of patients the diagnosis of small bowel CD is observer- and modality-dependent.

New concepts in intestinal imaging for inflammatory bowel diseases

In the last decade, multiple imaging technologies have been developed that improve visualization of the mucosal, mural, and perienteric inflammation associated with inflammatory bowel diseases. Whereas these technologies have traditionally been used to detect and stage suspected enteric inflammation, we review new, emerging roles in detecting clinically occult inflammation (in asymptomatic patients) and inflammatory complications, predicting response prior to therapy, assessing response after therapy, and enteric healing. We compare the relative performance of these technologies in detecting inflammation, focusing on their advantages and disadvantages and how they might complement each other. We also discuss their potential benefits for patients and clinical trials, reviewing technologic developments and areas of research that could provide important insights into the pathophysiology of inflammatory bowel diseases-related enteric inflammation.

Guide to magnetic resonance in Crohn's disease: from common findings to the more rare complicances

Considering that multiple imaging examinations are often necessary for monitoring Crohn's disease (CD) activity and severity in order to guide and monitor appropriate treatment, the ideal imaging test would be reproducible, well tolerated by patients, and free of ionizing radiation. For these reasons recent studies have highlighted the role of a magnetic resonance imaging (MRI) technique optimized for small bowel imaging in the evaluation of small bowel disorders. In this regard there are two main methodological approaches represented by MR enterography, following administration of an oral contrast medium, and MR enteroclysis, following administration of contrast medium through a nasojejuneal tube. MRI may be used to demonstrate the pathologic findings and complications of CD. In particular, MR has excellent sensitivity and specificity, ranging from 88%-98% and 78%-100%, respectively, for the detection of active inflammation, wall thickening, ulcerations, increased wall enhancement, increased vascularity, perienteric inflammation, and reactive adenopathy. MR also allows more accurate identification of associated complications including penetrating and fibrostenotic disease as well as the more rare extraintestinal manifestations that are usually associated with severe and longstanding intestinal inflammation, the latter often guiding the therapeutic approach. In the progression of CD some rare complications can occur that, to our knowledge, were only briefly or never mentioned in the radiological literature regarding MR enterography or enteroclysis and in which the application of these techniques play a key role.

Which magnetic resonance imaging findings accurately evaluate inflammation in small bowel Crohn's disease? A retrospective comparison with surgical pathologic analysis

BACKGROUND

The aim was to evaluate the value of magnetic resonance imaging (MRI) findings in Crohn's disease (CD) in correlation with pathological inflammatory score using surgical pathology analysis as a reference method.

METHODS

CD patients who were to undergo bowel resection surgery underwent MR enterography before surgery. The CD pathological inflammatory score of the surgical specimens was classified into three grades: mild or nonactive CD, moderately active CD, and severely active CD; fibrosis was also classified into three grades: mild, moderate, and severe. Mural and extramural MRI findings were correlated with pathological inflammatory and fibrosis grades.

RESULTS

Fifty-three consecutive patients were included retrospectively. The mean delay between MRI and surgery was 24 days (range 1-90, median 14). The CD pathological inflammatory score was graded as follows: grade 0 (11 patients, 21%), grade 1 (15 patients, 28%), and grade 2 (27 patients, 51%). MRI findings significantly associated with pathological inflammatory grading were wall thickness (P < 0.0001), degree of wall enhancement on delayed phase (P < 0.0001), pattern of enhancement on both parenchymatous (P = 0.02), and delayed phase, (P = 0.008), T2 relative hypersignal wall (P < 0.0001), blurred wall enhancement (P = 0.018), comb sign (P = 0.004), fistula (P < 0.0001), and abscess (P = 0.049). The inflammation score correlated with the fibrosis score (r = 0.63, P = 0.0001).

CONCLUSIONS

Our study identified MRI findings significantly associated with surgical pathological inflammation. These lesions are considered potentially reversible and may be efficiently treated medically. We also showed that fibrosis was closely and positively related to inflammation.

CT enterography: principles, trends, and interpretation of findings

Computed tomographic (CT) enterography is an emerging alternative to traditional fluoroscopy for the assessment of disorders of the small bowel. The greatly improved spatial and temporal resolution provided by multidetector CT scanners, combined with good luminal distention provided by negative oral contrast agents and with good bowel wall visualization, have made CT enterography the main imaging modality not only for investigating proved or suspected inflammatory bowel disease but also for detecting occult gastrointestinal tract bleeding, small bowel neoplasms, and mesenteric ischemia. CT enterography is particularly useful for differentiating between active and fibrotic bowel strictures in patients with Crohn disease, thus enabling selection of the most appropriate treatment (medical management or intervention) for an improved outcome. CT enterography allows excellent visualization of the entire thickness of the bowel wall and depicts extraenteric involvement as well, providing more detailed and comprehensive information about the extent and severity of the disease process.