Enteroclysis and spiral CT examination in diagnosis and evaluation of small bowel Crohn's disease

Iodine Quantification on Spectral Detector-Based Dual-Energy CT Enterography: Correlation with Crohn's Disease Activity Index and External Validation

Objective

To correlate CT parameters on detector-based dual-energy CT enterography (DECTE) with Crohn's disease activity index (CDAI) and externally validate quantitative CT parameters.

Materials and Methods

Thirty-nine patients with CD were retrospectively enrolled. Two radiologists reviewed DECTE images by consensus for qualitative and quantitative CT features. CT attenuation and iodine concentration for the diseased bowel were also measured. Univariate statistical tests were used to evaluate whether there was a significant difference in CTE features between remission and active groups, on the basis of the CDAI score. Pearson's correlation test and multiple linear regression analyses were used to assess the correlation between quantitative CT parameters and CDAI. For external validation, an additional 33 consecutive patients were recruited. The correlation and concordance rate were calculated between real and estimated CDAI.

Results

There were significant differences between remission and active groups in the bowel enhancement pattern, subjective degree of enhancement, mesenteric fat infiltration, comb sign, and obstruction (p < 0.05). Significant correlations were found between CDAI and quantitative CT parameters, including number of lesions (correlation coefficient, r = 0.573), bowel wall thickness (r = 0.477), iodine concentration (r = 0.744), and relative degree of enhancement (r = 0.541; p < 0.05). Iodine concentration remained the sole independent variable associated with CDAI in multivariate analysis (p = 0.001). The linear regression equation for CDAI (y) and iodine concentration (x) was y = 53.549x + 55.111. For validation patients, a significant correlation (r = 0.925; p < 0.001) and high concordance rate (87.9%, 29/33) were observed between real and estimated CDAIs.

Conclusion

Iodine concentration, measured on detector-based DECTE, represents a convenient and reproducible biomarker to monitor disease activity in CD.

Evaluation of bowel distension and bowel wall visualization according to patient positions during administration of oral contrast media for CT enterography

OBJECTIVE

To compare small bowel distension and bowel wall visualization among three different patients' positions (supine, sitting and right decubitus) during administration of oral contrast media in preparation for CT enterography (CTE).

METHODS

A total of 150 consecutive patients (104 males and 46 females; mean age 34.6 years, range 15-78 years) who were scheduled to undergo CTE were recruited. Patients were randomly allocated into the three position groups during oral contrast media administration, and there were 50 patients in each group. Two blinded radiologists independently scored the luminal distension and visualization of the bowel wall using a continuous 5-point scale (1: worst and 5: best) at the jejunum and ileum. The Mann-Whitney U test was used to evaluate differences between any two groups among the three positions for bowel distension and wall visualization.

RESULTS

For ileal distension, the supine and sitting positions performed better than the right decubitus position [for reader 1, mean: 3.4/3.2/2.9 (hereafter, supine/sitting/right decubitus in order), p = 0.002/0.033; for reader 2, 3.3/3.0/2.6, p < 0.001/0.027]. However, there was no significant difference among the three groups for jejunal distension (for reader 1, 2.4/2.3/2.2; for reader 2, 2.4/2.4/2.2, p > 0.05, respectively). For bowel wall visualization, the supine and sitting positions were superior to the right decubitus position for the ileum when scored by one reader (4.0/3.8/3.4, p = 0.001/0.015).

CONCLUSION

Supine and sitting positions during the administration of oral contrast media provided better ileal distension than the right decubitus position in obtaining CTE. Advances in knowledge: The performance of CTE largely depends on adequate luminal distension and wall visualization. As the terminal ileum is the predominant site of small bowel pathology for inflammatory bowel disease, the supine or sitting position would be preferable for patients who are suspected of having small bowel pathology.

Contrast-Enhanced Cross Sectional Imaging and Capsule Endoscopy: New Perspectives for a Whole Picture of the Small Bowel

Small bowel evaluation is a challenging task and has been revolutionized by high-quality contrasted sectional imaging (CT enterography - CTE) and magnetic resonance enterography (MRE) as well as by small bowel capsule endoscopy (SBCE). The decision of which technique to employ during the investigation of small bowel diseases is not always simple or straightforward. Moreover, contraindications may preclude the use of these techniques in some patients, and although they are noninvasive procedures, may present with various complications. SBCE plays a crucial role in the investigation of both obscure gastrointestinal bleeding and Crohn's disease, but it is also useful for surveillance of patients with Peutz-Jeghers syndrome, while CTE is very accurate in small bowel tumours and in established Crohn's Disease, and its use in patients presenting with gastrointestinal bleeding is increasing. MRE, an expensive and not widely available technique, is essential for the study of patients with Crohn's Disease, and presents an attractive alternative to SBCE in Peutz-Jeghers syndrome surveillance. These diagnostic modalities are often not competitive but synergistic techniques. Knowing their characteristics, strengths and limitations, indications, contraindications and potential complications, as well as the adaptation to local availability and expertise, is essential to better select which procedures to perform in each patient, both safely and effectively, in order to optimize management and improve patient outcomes.

Monitoring disease activity and progression in Crohn's disease. A Swiss perspective on the IBD ahead 'optimised monitoring' recommendations

BACKGROUND AND AIMS

The structured IBD Ahead 'Optimised Monitoring' programme was designed to obtain the opinion, insight and advice of gastroenterologists on optimising the monitoring of Crohn's disease activity in four settings: (1) assessment at diagnosis, (2) monitoring in symptomatic patients, (3) monitoring in asymptomatic patients, and (4) the postoperative follow-up. For each of these settings, four monitoring methods were discussed: (a) symptom assessment, (b) endoscopy, (c) laboratory markers, and (d) imaging. Based on literature search and expert opinion compiled during an international consensus meeting, recommendations were given to answer the question 'which diagnostic method, when, and how often'. The International IBD Ahead Expert Panel advised to tailor this guidance to the healthcare system and the special prerequisites of each country. The IBD Ahead Swiss National Steering Committee proposes best-practice recommendations adapted for Switzerland.

METHODS

The IBD Ahead Steering Committee identified key questions and provided the Swiss Expert Panel with a structured literature research. The expert panel agreed on a set of statements. During an international expert meeting the consolidated outcome of the national meetings was merged into final statements agreed by the participating International and National Steering Committee members - the IBD Ahead 'Optimized Monitoring' Consensus.

RESULTS

A systematic assessment of symptoms, endoscopy findings, and laboratory markers with special emphasis on faecal calprotectin is deemed necessary even in symptom-free patients. The choice of recommended imaging methods is adapted to the specific situation in Switzerland and highlights the importance of ultrasonography and magnetic resonance imaging besides endoscopy.

CONCLUSION

The recommendations stress the importance of monitoring disease activity on a regular basis and by objective parameters, such as faecal calprotectin and endoscopy with detailed documentation of findings. Physicians should not rely on symptoms only and adapt the monitoring schedule and choice of options to individual situations.

CT and MR enterography in children and adolescents with inflammatory bowel disease

The term inflammatory bowel disease (IBD) is used to describe multiple idiopathic disorders of the gastrointestinal tract. As many as one-quarter of patients with IBD initially present in childhood or adolescence. Multiple methods can be used to diagnose IBD in this age group, including computed tomographic (CT) enterography, magnetic resonance (MR) enterography, small bowel follow-through examination, ileocolonoscopy, and capsule endoscopy. However, CT enterography and MR enterography have become the imaging modalities of choice due to their exquisite image quality, rapid acquisition time, lack of need for bowel preparation, and ability to help diagnose the extraintestinal complications of IBD. In addition to being radiation free, MR enterography can help evaluate peristalsis, has high contrast resolution, and allows the use of diffusion-weighted imaging. The authors discuss the use of CT enterography and MR enterography in the context of pediatric IBD in terms of advantages and disadvantages, protocol, and imaging findings.

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.

Update imaging in inflammatory bowel diseases

Imaging is a central component of the diagnostic process in inflammatory bowel diseases. This review summarizes the recent progress of various most commonly used imaging modalities including computed tomography enterography, magnetic resonance enterography and capsule endoscopy. Advantages and disadvantages of each imaging protocol in suspected and established inflammatory bowel diseases are reviewed and brought into context in proposed diagnostic algorithms.

Cross-sectional imaging modalities in Crohn's disease

The standard tools assessing the activity of Crohn's disease (CD) measure the severity of symptoms (the Crohn's Disease Activity Index) or the degree of endoscopic lesions (the Crohn's Disease Endoscopic Index of Severity, the Simplified Endoscopy Score), not the global bowel damage. It is necessary to find new instruments able to assess the structural and functional damage to the intestine and the progression over time. We reviewed recent publications on the accuracy of abdominal ultrasound (US), computed tomography enterography (CTE), and magnetic resonance imaging enterography (MRE) for the assessment of CD. US, CTE and MRE have been shown to have a high and comparable diagnostic accuracy for both the diagnosis and complications of CD, but US and MRE have the major advantage of not imparting ionizing radiation. In summary, findings from these imaging modalities with endoscopic lesions and surgical history incorporating into the Lémann score will allow measuring the global bowel damage at specific time and the progression of disease over time and assessing the impact of different strategies.

Resistance index in mural arteries of thickened bowel wall: predictive value for Crohn disease activity assessment in pediatric patients

OBJECTIVE

To define reliable Doppler parameters in mural arteries of affected bowel loops for quantitative assessment of Crohn disease (CD) activity in pediatric population and compare Doppler parameters with Pediatric Crohn Disease Activity Index (PCDAI).

PATIENTS AND METHODS

Thirty-four pediatric patients (7 with inactive, 27 with active disease of different severity; 13 male and 21 female; mean age 13; range 7-18) with CD were prospectively evaluated by Doppler ultrasound (DUS) of affected bowel segments. Using semiquantitative color and power Doppler assessment of vascularization of thickened bowel wall and mesentery, patients were divided in four grades. Spectral measurements (peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI)) of mural arteries were compared with PCDAI.

RESULTS

There was a significant difference in distribution of semiquantitative color values between inactive and active group. PSV and EDV values showed no significant difference between inactive and active group, while mean RI was significantly higher in the inactive group. RI was also significantly negatively correlated with PCDAI.

CONCLUSION

Intensity of color and power Doppler signals and RI measurement of mural arteries in thickened bowel wall is linked to CD activity and therefore might be of use in pediatric patients.

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.

Transmural inflammation is not pathognomonic for Crohn's disease of the pouch

BACKGROUND

Transmural inflammation shown by imaging and histology has been considered a hallmark of Crohn's disease (CD). However, the diagnostic and prognostic value of this feature in CD of the pouch has not been evaluated. This study aimed to evaluate the clinical utility of transmural inflammation in patients with ileal pouch-anal anastomosis (IPAA) using in vivo optical coherence tomography (OCT) and histopathology.

METHODS

All the patients were recruited from the subspecialty Pouchitis Clinic. The study consisted of two parts: (1) a prospective study with in vivo through-the-scope OCT for the evaluation of transmural disease in patients with normal or diseased pouches and (2) a retrospective pathology re-review for transmural inflammation in excised pouch specimens of CD and chronic pouchitis.

RESULTS

This prospective OCT study enrolled 53 patients: 11 (20.8%) with normal pouches or irritable pouch syndrome, 10 (18.9%) with acute pouchitis, 11 (20.8%) with chronic antibiotic-refractory pouchitis (CARP), and 21 (39.6%) with CD of the pouch. Transmural inflammation, characterized by the loss of layered structure on OCT, was detected in 16 patients (30.2%): 4 with chronic pouchitis and 12 with CD of the pouch. None of the patients with normal pouches, irritable pouch syndrome, or acute pouchitis had transmural disease shown on OCT. Of the 26 patients with pouch failure who had pouch excision, the surgical specimens showed transmural disease in 30% of the CARP patients (3/10) and 12.5% (2/16) of those with CD of the pouch.

CONCLUSIONS

Transmural disease in the setting of IPAA is not pathognomonic of CD. Transmural inflammation shown by imaging or histopathology was seen in both CD and CARP. Transmural inflammation of the pouch appeared to be associated with poor pouch outcome.

Development of the Crohn's disease digestive damage score, the Lémann score

Crohn's disease (CD) is a chronic progressive destructive disease. Currently available instruments measure disease activity at a specific point in time. An instrument to measure cumulative structural damage to the bowel, which may predict long-term disability, is needed. The aim of this article is to outline the methods to develop an instrument that can measure cumulative bowel damage. The project is being conducted by the International Program to develop New Indexes in Crohn's disease (IPNIC) group. This instrument, called the Crohn's Disease Digestive Damage Score (the Lémann score), should take into account damage location, severity, extent, progression, and reversibility, as measured by diagnostic imaging modalities and the history of surgical resection. It should not be "diagnostic modality driven": for each lesion and location, a modality appropriate for the anatomic site (for example: computed tomography or magnetic resonance imaging enterography, and colonoscopy) will be used. A total of 24 centers from 15 countries will be involved in a cross-sectional study, which will include up to 240 patients with stratification according to disease location and duration. At least 120 additional patients will be included in the study to validate the score. The Lémann score is expected to be able to portray a patient's disease course on a double-axis graph, with time as the x-axis, bowel damage severity as the y-axis, and the slope of the line connecting data points as a measure of disease progression. This instrument could be used to assess the effect of various medical therapies on the progression of bowel damage.

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.

CT enterography with polyethylene glycol solution vs CT enteroclysis in small bowel disease

OBJECTIVE

The aim of the study is to compare CT enterography with polyethylene glycol solution (PEG-CT) with CT enteroclysis (CT-E) in patients with suspected small bowel disease.

METHODS

145 patients underwent abdominal contrast-enhanced 16-row multidetector CT after administration of 2000 ml of PEG by mouth (n = 75) or after administration of 2000 ml of methylcellulose by nasojejunal tube (n = 70). Small bowel distension, luminal and extraluminal findings were evaluated and compared with small bowel follow-through examination in 60 patients, double contrast enema in 50, surgery in 25 and endoscopy in 35. Statistical evaluation was carried out by χ² testing. For both techniques we have also calculated the effective dose and the equivalent dose in a standard patient.

RESULTS

Crohn's disease was diagnosed in 64 patients, neoplasms in 16, adhesions in 6. Distension of the jejunum was better with CT-E than PEG-CT (p<0.05: statistically significant difference). No significant difference was present for others sites (p>0.05). Evaluation of pathological ileal loops was good with both techniques. The values of sensitivity, specificity and diagnostic accuracy were respectively 94%, 100% and 96% with CT-E, and 93%, 94% and 93% with PEG-CT. The effective dose for PEG-CT was less than the dose for the CT-E (34.7 mSv vs 39.91 mSv).

CONCLUSION

PEG-CT shows findings of Crohn's disease as well as CT-E does, although CT-E gives better bowel distension, especially in the jejunum, and has higher specificity than PEG-CT.

Role of small bowel follow-through in diagnosing inflammation of the terminal ileum in pediatric patients

BACKGROUND

The small bowel follow-through (SBFT) is a noninvasive imaging modality for evaluating terminal ileum (TI) inflammation. The accuracy of this modality in pediatric patients is not well established.

PATIENTS AND METHODS

We retrospectively determined the sensitivity and specificity of SBFT for detecting TI inflammation diagnosed on histology in 93 pediatric patients studied in a single institution.

RESULTS

The mean age at the first study was 12.9 years (range 1.1-20.9 years). Forty-five percent were girls. Twenty-five patients (27%) had abnormal TIs on SBFT. Seventeen patients (18%) had TI inflammation diagnosed by biopsy. The sensitivity of SBFT was 59% and the specificity was 80% for detecting TI inflammation diagnosed on histology. Sensitivity and specificity did not change by demographic factors, final diagnoses, presenting symptoms, or laboratory parameters, reflecting the presence of intestinal inflammation.

CONCLUSIONS

The sensitivity and specificity of SBFT in pediatric patients were poor and did not vary with demographic factors, final diagnoses, presenting symptoms, or laboratory parameters. Prospective longitudinal studies comparing various imaging modalities (SBFT, magnetic resonance enterography, and capsule endoscopy) are required to determine which is the most effective tool for evaluating pediatric patients for TI inflammation.

ACR Appropriateness Criteria on Crohn's disease

In the past decade, new therapeutic agents have been developed that permit gastroenterologists to treat virtually all forms of Crohn's disease. The success of these treatments depends on an accurate diagnosis of the nature and extent of disease. Fortunately, radiologists now possess a powerful arsenal of imaging techniques to guide the choice of therapy. This article discusses the usefulness of both traditional and newer imaging techniques in the management of Crohn's disease and its various clinical presentations.

CT enterography technique: theme and variations

CT enterography has rapidly gained acceptance as a method for visualizing the small bowel lumen, wall and mesentery for a variety of clinical indications. Focusing on the identification of Crohn's disease, and vascular and neoplastic small bowel masses, this review summarizes oral contrast agents and CT acquisition techniques used for CT enterography, alternatives that can be used to tailor the exam for specific indications, and how such variations affect the appearance of a variety of pathologies at CT imaging.

CT findings and clinical activity in Crohn's disease

The aim of this study was to evaluate clinical correlations of CT signs in proven Crohn's disease. Fifty patients were studied by means of multidetector CT. Clinical activity was assessed using Crohn's disease activity index (CDAI) score and some laboratory parameters. All patients with CDAI>150 had CT study scored as pathological. Seventy-nine percent of patients with CDAI<150 showed abnormalities in CT exam. CT findings correlate with some parameters of disease activity, thus underlining the usefulness of performing CT enteroclysis in Crohn's disease patients.

Frequency and nature of incidental extra-enteric lesions found on magnetic resonance enterography (MR-E) in patients with inflammatory bowel diseases (IBD)

Background

The aim of this study was to determine the occurrence of extra-enteric findings in a large cohort of patients undergoing magnetic resonance enterography (MR-E) and to classify the clinical significance of these findings.

Materials and Methods

We retrospectively analyzed 1154 MR-E performed in 1006 patients referred to our radiological department between 1999–2005. The reasons for referral were suspected or proven inflammatory bowel diseases (IBD) (n = 710), further diagnostic work-up for small bowel disease because of non-specific abdominal symptoms (SBD; n = 182) or suspected small bowel malignancies (SBM; n = 114). All extra-enteric findings were reviewed by a radiologist and a gastroenterologist and were classified as having high, moderate, or low significance for further diagnostic or therapeutic procedures.

Results

The average age of all patients was 40±16 (Mean±SD) years (y) (IBD 35±13 y; SBD 49±16 y; SBM 57±15 y). A total of 1113 extra-enteric findings were detected in 600 of 1006 patients (59.6%). Of these findings 180 (16.2%) were judged as having a high, 212 (19.0%) a moderate and 721 (64.8%) a low significance. On a per group basis in patients with IBD 12.0% of the findings were of major clinical significance compared to 13.7% and 33.3% in patients with SBD and SBM, respectively. The most common major findings were abscesses (69.9%) in the IBD group and extraintestinal tumors, metastases or masses in the SBD and SBM groups (41.9% and 74.2%, respectively).

Conclusions

MR-E reveals a substantial number of extra-enteric findings, supporting the role of a cross-sectional imaging method for the evaluation of the small bowel.

Antiglycan antibodies as serological markers in the differential diagnosis of inflammatory bowel disease

BACKGROUND

The objective of the study was to evaluate the diagnostic accuracy of recently developed antiglycan serological tests in clinical practice for the diagnosis of Crohn's disease.

METHODS

This study was a cohort analysis of both clinical and biochemical parameters of patients with diagnosed inflammatory bowel disease compared with those in a control population. Antiglycan antibodies were determined using commercially available enzyme immunoassays. The setting was the outpatient unit of the gastroenterology department of a large, tertiary-care referral academic hospital. Participants were 214 consecutive patients, enrolled over a 5-month period, including 116 with Crohn's disease and 53 with ulcerative colitis, as well as 45 with other gastrointestinal diseases and 51 healthy controls.

RESULTS

Anti-Saccharomyces cerevisiae antibodies showed the best performance (54% sensitivity and 88%-95% specificity for Crohn's disease). Among patients with negative anti-Saccharomyces antibodies, 19 (34%) had high titers of at least another tested antiglycan antibody. Anti-Saccharomyces and anti-laminaribioside antibodies were associated with disease involving the small bowel and with penetrating or stricturing phenotype. Anti-laminaribioside was significantly higher in patients with a familial history of inflammatory bowel disease.

CONCLUSIONS

The new proposed serological markers are significantly associated with Crohn's disease, with low sensitivity but good specificity. About one third of anti-Saccharomyces-negative patients may be positive for at least 1 of those markers. Antiglycan antibodies appear to be associated with characteristic localization and phenotype of the disease.

CT enteroclysis: multidetector technique (MDCT) versus single-detector technique (SDCT) in patients with suspected small-bowel Crohn's disease

PURPOSE

This study was done to evaluate the diagnostic role of enteroclysis with multidetector computed tomography (MDCT) and single-detector CT (SDCT) in patients affected by small-bowel Crohn's disease.

MATERIALS AND METHODS

Forty-five patients underwent abdominal SDCT (n=20) or 16-row MDCT (n=25) after administration of methylcellulose by nasojejunal tube. Each examination was assessed for small-bowel distension and site and characteristics of the diseased loops. The two CT techniques were then compared. Results were compared with double-contrast enteroclysis performed in all patients and with ileoscopy performed in 28 patients.

RESULTS

In comparison with double-contrast enteroclysis, sensitivity, specificity and diagnostic accuracy were 90%, 71% and 89% for SDCT and 92%, 83% and 90% for MDCT. Ileoscopy confirmed the absence of disease in five patients and the presence of Crohn's disease in 20. Compared with SDCT, MDCT reduced scanning time and respiratory artefacts and permitted better multiplanar reconstructions.

CONCLUSIONS

MDCT is superior to SDCT because it allows a better spatial resolution and improves depiction of the pathological patterns of Crohn's disease.

Correlation of CT enteroclysis with surgical pathology in Crohn's disease

BACKGROUND

The response to therapy in Crohn's disease (CD) depends on the inflammatory or fibrostenotic nature of the underlying pathological process. Standard diagnostic tests cannot reliably distinguish between these two entities. Although CT enteroclysis (CTE) has shown promise in the evaluation of small bowel disorders, its accuracy for the differentiation of CD phenotypes is unknown.

AIMS

To determine the accuracy of CTE compared with surgical pathology in patients with CD and to assess the association of CTE variables with inflammatory or fibrostenotic pathological lesions.

METHODS

CTE studies from patients who underwent resective bowel surgery for CD were reviewed and compared with the pathological specimens using a standardized scoring system. Patients were excluded if they had incomplete studies, nonresective surgeries, or a diagnosis of malignancy. CTE variables, such as mucosal and mural enhancement, wall thickness, engorgement of vasa recta (comb sign), adenopathy, and the presence and severity of strictures were compared with the pathology results using Mantel-Haenszel chi2, Spearman's rank coefficient, and logistic regression analyses.

RESULTS

Of the 54 patients enrolled, 10 were excluded. The remaining patients (61% female, 84% white) underwent 44 surgical interventions generating 47 bowel segments that were included in the analysis. The indications for surgery were: bowel obstruction in 21; perforating disease in 13; and refractory, nonobstructive disease in 15. The accuracy of CTE for inflammatory and fibrostenotic lesions was 76.6% and 78.7% using a four- and three-point grading system, respectively. There was good correlation between CTE and pathology in regards to inflammation (Spearman's r = 0.7, P < 0.0001) and fibrostenosis (Spearman's r = 0.6, P < 0.0001) scores. The pathological inflammation score was significantly associated with the CTE variables mucosal enhancement, wall thickness, comb sign, and adenopathy (Mantel-Haenszel chi2 P values 0.04, 0.04, <0.0001, and 0.016, respectively). The pathological fibrostenosis score was significantly associated with the presence and severity of stenosis on CTE (P= 0.001 and 0.007, respectively). By logistic regression analysis, the strongest association was seen with the comb sign (OR 5.52, P < 0.001) for inflammation and the presence of stenosis (OR 5.87, P= 0.006) for fibrostenosis. There was no interaction between the time interval from CTE to surgery and the strength of these associations.

CONCLUSIONS

CTE may reliably differentiate between inflammatory and fibrostenotic lesions and may have an important role in the management of CD. Specific CTE variables correlate with each of these phenotypes and deserve further investigations in prospective studies.

Multidetector CT in small-bowel neoplasms

PURPOSE

The aim of this study was to assess the diagnostic potential of multidetector computed tomography (MDCT) in the evaluation of small-bowel neoplasms.

MATERIALS AND METHODS

We studied 120 patients with suspected small-bowel disease by 16-slice MDCT after oral administration of a polyethylene glycol solution (n=56) or methylcellulose via a nasojejunal tube (n=64). Unenhanced and contrast-enhanced CT was performed. Contrast-enhanced CT images were acquired 40 s after IV injection of 130 ml of iodinated contrast agent at a rate of 3 ml/s. Multiplanar reconstructions were performed at the end of the examinations.

RESULTS

Fifteen patients were found to be affected by small-bowel neoplasm (six had non-Hodgkin's lymphoma, three had carcinoid tumour, two had Peutz-Jeghers syndrome, two had adenocarcinoma, two had melanoma metastases, one had lipoma). In the remaining patients, 58 cases of Crohn's disease and seven miscellaneous diseases were detected. All findings were confirmed by barium studies, surgery or endoscopy.

CONCLUSIONS

MDCT performed after bowel-loop distension with low-density contrast material and IV administration of iodinated contrast agent is a reliable method for diagnosing and staging small-bowel neoplasms.

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.

CT enterography: noninvasive evaluation of Crohn's disease and obscure gastrointestinal bleed

CT enterography (CTE) is a noninvasive imaging test using neutral intraluminal contrast and intravenous contrast to evaluate the small bowel. Multiphasic imaging is used in evaluating obscure gastrointestinal bleeding (OGIB), and single-phase enteric imaging is used for all other indications, including Crohn's disease (CD). CTE findings of CD include bowel wall thickening, mucosal hyperenhancement, and mural stratification. CTE findings of angiodyplasias include a vascular tuft visible during arterial phase and an early draining mesenteric vein. Early studies indicate that CTE is superior to barium examination in the evaluation of CD and is complementary to capsule endoscopy in the evaluation of OGIB.

Imaging of the small bowel in Crohn's disease: A review of old and new techniques

The investigation of small bowel morphology is often mandatory in many patients with Crohn’s disease. Traditional radiological techniques (small bowel enteroclysis and small bowel follow-through) have long been the only suitable methods for this purpose. In recent years, several alternative imaging techniques have been proposed. To review the most recent advances in imaging studies of the small bowel, with particular reference to their possible application in Crohn’s disease, we conducted a complete review of the most important studies in which traditional and newer imaging methods were performed and compared in patients with Crohn’s disease. Several radiological and endoscopic techniques are now available for the study of the small bowel; each of them is characterized by a distinct profile of favourable and unfavourable features. In some cases, they may also be used as complementary rather than alternative techniques. In everyday practice, the choice of the technique to be used stands upon its availability and a careful evaluation of diagnostic accuracy, clinical usefulness, safety and cost. The recent development of innovative imaging techniques has opened a new and exciting area in the exploration of the small bowel in Crohn’s disease patients.

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.

Crohn's disease at the small bowel imaging by the ultrasound-enteroclysis

Crohn's disease is more likely a systemic disease governed by a shift in the immune response, thus affecting the whole MALT system. Its treatment should be as conservative as possible and surgery is usually taking place after complications like indolent fistulations, stenoses, bleeding, or bowel perforation started. Standard radiological methods to check the extent of the disease are loaded either with certain radiation exposure (enteroclysis, CT) or lack standardization (ultrasound). The aim of this small study was to evaluate the worth of ultrasound-enteroclysis in detecting the extent and complications of the Crohn's disease in surgically treated patients.

MATERIAL AND METHODS

Since 1997, when we started with the ultrasound-enteroclysis, 246 surgical performances were involved into our study. Out of them, 181 had conventional abdominal intestinal ultrasound as well as conventional enteroclysis within 1 week. Remaining 65 cases were diagnosed by the ultrasound-enteroclysis. Intestinal ultrasound was performed on the Ultramark 3000 HDI device with autofocussable convex 5 MHz and linear 7.5 MHz probes or nowadays ATL 5000 HDI, 7-12 MHz linear probe. No contrast enhancement was used. Enteroclysis was done with the Micropaque suspension diluted 1:1 with HP-7000 300 ml with its application rate up to 75 ml/min followed by HP-7000 solution 2000 ml, application rate of 120 ml/min. The patients with ultrasound-enteroclysis were applied HP 7000 solution only (2000 ml, rate 100ml/s) via an enteroclysis catheter. All investigations were video-recorded.

RESULTS

Consent with the per-operative finding was reached in 162 from 181 enteroclyses and in 169 of 181 ultrasounds. Ultrasound-enteroclysis was precise in 61 cases from 65. Among these, 60 patients had the recurrence during the treatment proved by clinical and laboratory results. This re-activation was clearly revealed in 38 from 43 cases by enteroclysis, 41 from 43 by US and in 16 from 17 by ultrasound-enteroclysis. From 30 patients that developed acute complication non-responding to the conservative therapy (abscesses, fistulas and intestinal obstructions) there were 18 from 20 accurately diagnosed by enteroclysis, only 12 from 20 by US and 9 from 10 by US-enteroclysis. The differences were either statistically non-significant or there were too small numbers to give sensible statistical results, but low sensitivity of ultrasound in complications (p=0.05).

CONCLUSION

US-enteroclysis seems to became the standard examination of patients with Crohn's disease mainly in those with unclear conventional ultrasound. The most important fact is that this examination significantly decreases the radiation load when maintaining high sensitivity. This is very important namely in patients with Crohn's disease that require life-long observation and repeated examinations. This examination is much more easy to standardize than the conventional US.

Técnicas seccionales de imagen en la enfermedad de Crohn: ecografía, tomografía computarizada y resonancia magnética

Colonoscopy and Barium contrast studies continue to be the techniques of choice for the evaluation of mucosal lesions in Crohn's disease. However, these techniques have limited capacity for demonstrating the transmural and extramural extension of the disease. Although ultrasound, CT, and MRI cannot detect early lesions, these techniques satisfactorily show parietal and extraparietal changes caused by the disease, thus complementing the information provided in conventional studies. These three techniques enable the evaluation of the pathological segments, the presence of stenosis and dilatation, and extramural disease (fibrofatty proliferation, fistulae, phlegmons, and abscesses). This information is essential for classifying each patient into one of the three subtypes of Crohn's disease (inflammatory, stenotic, or fistulating). These techniques also enable the evaluation of signs that indicate inflammatory activity (hyperemia, wall enhancement, and increased mesenteric vascularization), and this information, together with the subtype, will determine the treatment. Ultrasound, CT, and MRI should be included in the complete evaluation of the patient with Crohn's disease, together with clinical examination, laboratory tests, and conventional imaging studies. We review the role of ultrasound, CT, and MRI in the diagnosis and evaluation of Crohn's disease, describing patient preparation and examination protocols, as well as the findings in these three techniques. We also discuss the advantages and limitations of each of these techniques and their current clinical roles in this context.

Active Crohn disease: CT findings and interobserver agreement for enteric phase CT enterography

PURPOSE

To retrospectively evaluate small-bowel enhancement characteristics and the sensitivity, specificity, and interobserver agreement of computed tomographic (CT) findings by using histologic and endoscopic results as a reference standard in patients undergoing enteric phase CT enterography.

MATERIALS AND METHODS

The institutional review board approved this retrospective HIPAA-compliant study, which included patients who consented to having their medical records used for research purposes. Enteric phase CT enterographic and ileoscopic findings with or without ileal histologic results were examined in 42 patients (24 women, 18 men). Enteric phase CT enterography was performed after 150 mL of intravenous contrast material was administered at 4 mL/sec, with a 45-second delay. Mural attenuation was measured in the distended and collapsed jejunal and ileal loops and in the terminal ileum. Two radiologists examined CT images for findings of Crohn disease. Mural attenuation for different bowel loops was compared by using a Student t test, with kappa statistics used to measure interobserver agreement and Pearson correleation coefficients used to compare visual and quantitative measures.

RESULTS

Distended jejunal loops had significantly greater attenuation than distended ileal loops (113 HU vs 72 HU; P < .001). Attenuation of collapsed jejunal (134 HU) and ileal (108 HU) loops was greater than that of distended jejunal and ileal loops (P < .001). Terminal ileal enhancement was the most sensitive visual CT finding of Crohn disease for both radiologists. Mural thickening demonstrated the greatest interobserver agreement (kappa = 0.83). Visual enhancement and quantitative mural attenuation were significantly correlated (P < .003).

CONCLUSION

At enteric phase CT enterography, jejunal attenuation is greater than ileal attenuation and collapsed bowel loops demonstrate greater attenuation than distended bowel loops. Mural hyperenhancement and increased mural thickness are the most sensitive CT findings of active Crohn disease.

CT enterography as a diagnostic tool in evaluating small bowel disorders: review of clinical experience with over 700 cases

Computed tomographic (CT) enterography combines the improved spatial and temporal resolution of multi-detector row CT with large volumes of ingested neutral enteric contrast material to permit visualization of the small bowel wall and lumen. Adequate luminal distention can usually be achieved with oral hyperhydration, thereby obviating nasoenteric intubation and making CT enterography a useful, well-tolerated study for the evaluation of diseases affecting the mucosa and bowel wall. Unlike routine CT, which has been used to detect the extraenteric complications of Crohn disease such as fistula and abscess, CT enterography clearly depicts the small bowel inflammation associated with Crohn disease by displaying mural hyperenhancement, stratification, and thickening; engorged vasa recta; and perienteric inflammatory changes. As a result, CT enterography is becoming the first-line modality for the evaluation of suspected inflammatory bowel disease. CT enterography has also become an important alternative to traditional fluoroscopy in the assessment of other small bowel disorders such as celiac sprue and small bowel neoplasms.

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.

Multidetector CT enteroclysis versus barium enteroclysis with methylcellulose in patients with suspected small bowel disease

The purpose of this study was to evaluate the diagnostic accuracy of multidetector-CT enteroclysis (MDCT-E) versus barium enteroclysis with methylcellulose (BE) in clinically selected patients with suspected small bowel disease. We prospectively studied 52 patients who underwent unenhanced and contrast-enhanced multidetector CT (16 rows) after administration of 2-2.5 l of methylcellulose by naso-jejunal tube. BE was performed after administration of barium 60% w/v (200-250 ml) and methylcellulose (1-2 l). Patients with radiological signs of Crohn's disease were classified into the following subtypes: active, fibrostenotic, fistulising/perforating, reparative or regenerative subtypes. Twenty-eight patients also underwent endoscopy. The radiological prevalent subtype was the active subtype. The sensitivity, specificity and diagnostic accuracy of MDCT-E versus BE was 83%, 100% and 89%, respectively. BE showed five false negative CT cases due to early Crohn's disease; endoscopy confirmed positive cases of the CT and the BE, but showed one false negative case of the BE. Together, MDCT enteroclysis and BE permitted the diagnosis of Crohn's disease in 30 patients, adhesions in one patient, lymphoma in two patients and carcinoid tumours in two patients. In conclusion, MDCT-E permits good representation of pathological patterns. Early stages of Crohn's disease are better evaluated by BE.

Crohn Disease: mural attenuation and thickness at contrast-enhanced CT Enterography--correlation with endoscopic and histologic findings of inflammation

PURPOSE

To determine retrospectively if quantitative measures of small-bowel mural attenuation and thickness at computed tomographic (CT) enterography correlate with endoscopic and histologic findings of small-bowel inflammation and to estimate the performance of these measures in predicting inflammatory Crohn disease.

MATERIALS AND METHODS

The institutional review board approved this HIPAA-compliant retrospective study, which was conducted with patient informed consent. CT enterography data in 96 patients (31 male patients and 65 female patients) who underwent ileoscopy with or without biopsy were examined for CT signs of active Crohn disease. The most highly enhancing segment of terminal ileum and a normal-appearing ileal loop were identified. After it was confirmed that semiautomated software could accurately measure mural attenuation and thickness, the selected terminal ileal and normal-appearing (control) ileal loops were examined (20 automated measurements at each location) to quantify mural attenuation and wall thickness. Results were compared with endoscopy and histology reports by using logistic regression analysis and receiver operating characteristic curves.

RESULTS

Quantitative measures of terminal ileal mural attenuation and wall thickness correlated significantly with active Crohn disease (P < .001). Small-bowel wall thickness was not a significant factor after attenuation was taken into account. A threshold attenuation value with a sensitivity of 90% (18 of 20) for definite Crohn disease (compared with a sensitivity of 80% [16 of 20] for radiologist assessment) was selected. In patients who underwent ileal biopsy, threshold attenuation had a sensitivity identical to that of ileoscopy (81% [26 of 32]; 95% confidence interval: 64%, 93%) in predicting histologic inflammation.

CONCLUSION

Quantitative measures of mural attenuation and wall thickness at CT enterography correlate highly with ileoscopic and histologic findings of inflammatory Crohn disease. Quantitative measures of mural attenuation are sensitive markers of small bowel inflammation.

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.

Multi-detector CT enterography with iso-osmotic mannitol as oral contrast for detecting small bowel disease

AIM: To assess the feasibility and usefulness of multi-detector CT enterography with orally administered iso-osmotic mannitol as negative contrast in demonstrating small bowel disease.

METHODS: Thirteen volunteers and 38 patients with various kinds of small bowel disease were examined. We administered about 1500 mL iso-osmotic mannitol as negative contrast agent and then proceeded with helical CT scanning on a Siemens Sensation 16 scanner. All volunteers and patients were interviewed about their tolerance of the procedure. Two radiologists post-processed imaging data with MPR, thin MIP, VRT and INSPACE when necessary and then interpreted the scans, and adequacy of luminal distention was evaluated on a four-point scale. Demonstration of features of various kinds of small bowel disease was analyzed.

RESULTS: The taste of iso-osmotic mannitol is good (slightly sweet) and acceptable by all. Small bowel distention was excellent and moderate in most volunteers and patients. CT features of many kinds of diseases such as tumors, Crohn’s disease,and small bowel obstruction, etc. were clearly displayed.

CONCLUSION: Multi-detector CT enterography with iso-osmotic mannitol as negative contrast to distend the small bowel is a simple, rapid, noninvasive and effective method of evaluating small bowel disease.

Ex vivo histology-correlated optical coherence tomography in the detection of transmural inflammation in Crohn's disease

BACKGROUND AND AIMS

Distinguishing Crohn's disease (CD) from ulcerative colitis (UC) can be difficult. Transmural inflammation, a key feature of CD, cannot be assessed by conventional colonoscopy with biopsy. Optical coherence tomography (OCT) provides high-resolution, cross-sectional images of the gut wall and might become a new diagnostic tool. The aims of this study were to perform histology-correlated OCT on surgical specimens of CD and UC and to determine its diagnostic accuracy.

METHODS

Colectomy specimens from patients with a preoperative diagnosis of CD (N = 24) or UC (N = 24) were studied with OCT in the operating room. OCT and histopathology were assessed blindly, and diagnostic accuracy of OCT was assessed.

RESULTS

Eight preoperatively identified UC patients (33%) with transmural inflammation on postoperative histology were diagnosed with CD, and all 8 had a disrupted layered structure on OCT, a characteristic feature of transmural disease. Sixteen UC patients (67%) had superficial inflammation on histology; of them, 13 (81%) had an intact layered structure on OCT. All 24 preoperative CD patients had transmural inflammation on histology, and 23 (96%) had a disrupted layered structure on OCT. Of 585 histology-OCT image sets from the 48 patients, 152 sets (26%) had transmural inflammation on histology. The sensitivity and specificity for OCT to detect transmural disease were 86% and 91%, respectively.

CONCLUSIONS

Transmural inflammation, as characterized by disruption of the layered structure of colon wall on OCT, is an accurate marker for the diagnosis of CD. Ex vivo OCT predicted transmural inflammation on postoperative histopathology.

Cross-sectional imaging in Crohn disease

The role of cross-sectional imaging in the diagnosis of Crohn disease has expanded with recent technologic advances in computed tomography (CT) and magnetic resonance (MR) imaging that allow rapid acquisition of high-resolution images of the intestines. To acquire images of diagnostic quality, administration of a fairly large amount of intraluminal contrast agent prior to examination and scanning with intravenous contrast material injection are necessary. Both CT and MR imaging are reported to have a sensitivity of over 95% for the detection of Crohn disease; however, they may not allow early diagnosis. Colonoscopy and conventional enteroclysis studies are indicated for patients with early-stage disease. At more advanced stages, CT and MR imaging can help identify and characterize pathologically altered bowel segments as well as extraluminal lesions (eg, fistulas, abscesses, fibrofatty proliferation, increased vascularity of the vasa recta, mesenteric lymphadenopathy). These modalities can also clearly depict inflammatory lesion activity and conditions that require elective gastrointestinal surgery, thereby aiding in treatment planning. In the clinical setting, CT is currently the imaging modality of choice at most institutions; however, it is expected that MR imaging will soon play a comparable role. CT or MR imaging should be included in a comprehensive evaluation of patients with Crohn disease, along with conventional imaging and clinical and laboratory tests.

Modern imaging using computer tomography and magnetic resonance imaging for inflammatory bowel disease (IBD) AU1

Radiologic imaging--especially of the small bowel--plays an important role in the diagnosis and management of patients with inflammatory bowel disease. The radiographic examination of the small intestine with barium either as enteroclysis or as small bowel follow through are still the mainstays in small bowel imaging. However, abdominal CT or MRI, which has the advantage of not utilizing ionizing radiation, or the techniques of CT- or MR-enteroclysis, are overall comparable with regard to the sensitivity and specificity in detecting intestinal pathologies and have already replaced the conventional techniques in centers dedicated to the management of inflammatory bowel disease. Additionally, these cross-sectional imaging techniques provide, in a sense, a "one stop abdominal imaging workup," the diagnosis of extraluminal disease manifestations or complications. Future developments of CT- or MR-based virtual colonography and endoscopy in patients with inflammatory bowel disease are currently being investigated, but should momentarily be considered as purely experimental approaches.

Imaging of inflammatory bowel disease: CT and MR

Cross-sectional imaging has come to play a central role in the imaging of the abdomen. Concurrent to this, the role of CT and MRI in the imaging of inflammatory bowel disease has also increased in importance. These modalities offer numerous advantages over more traditional methods of radiologic diagnosis, and provide essential information not only for initial diagnosis, but for management, follow-up and detection of potential complications. On the horizon are several derivative techniques involving CT and MRI, potentially in combination with PET imaging; these may further improve the specificity and sensitivity of imaging modalities for diagnosis of inflammatory bowel disease.