Crohn disease with endoscopic correlation: single-shot fast spin-echo and gadolinium-enhanced fat-suppressed spoiled gradient-echo MR imaging

Influence of diffusion weighted imaging and contrast enhanced T1 sequences on the diagnostic accuracy of magnetic resonance enterography for Crohn's disease

OBJECTIVES

To evaluate the additional diagnostic benefit of diffusion weighted imaging (DWI) and contrast enhanced (CE) images during MR enterography (MRE) of Crohn's disease.

METHODS

Datasets from 73 patients (mean age 32; 40 male) (28 new-diagnosis, 45 relapsed) were read independently by two radiologists selected from a pool of 13. Radiologists interpreted datasets using three sequential sequence blocks: (1) T2 weighted and steady state free precession gradient echo (SSFP) images alone (T2^); (2) T2 weighted and SSFP images with DWI (T2 + DWI^) and; (3) T2 weighted images, SSFP, DWI and post-contrast enhanced (CE) T1 images (T2 + DWI + CE^), documenting presence, location, and activity of small bowel disease. For each sequence block, sensitivity and specificity (readers combined) was calculated against an outcome-based construct reference standard.

RESULTS

59/73 patients had small bowel disease. Per-patient sensitivity for disease detection was essentially identical (80 % [95 % CI 72, 86], 81 % [73,87], and 79 % [71,86] for T2^, T2 + DWI^and T2 + DWI + CE^respectively). Specificity was identical (82 % [64 to 92]). Per patient sensitivity for disease extent was 56 % (47,65), 56 % (47,65) and 52 % (43 to 61) respectively, and specificity was 82 % (64 to 92) for all blocks. Sensitivity for active disease was 97 % (90,99), 97 % (90,99) and 98 % (92,99), and specificity was also comparable between all sequence combination reads. Results were consistent across segments and newly diagnosed/relapse patients.

CONCLUSION

There is no additional diagnostic benefit of adding either DWI or CE to T2 FSE and SSFP sequences for evaluating small bowel Crohn's disease, suggesting MRE protocols can be simplified safely.

Effectiveness of transabdominal ultrasonography in predicting clinical relapse of Crohn's disease

BACKGROUND/AIMS

Transabdominal ultrasonography (US) helps evaluate Crohn's disease (CD) activity. We investigated whether the US could predict subsequent adverse outcomes for patients with CD in clinical remission.

METHODS

This single-center retrospective study included patients with CD in clinical remission who underwent US between April 2011 and April 2021, focusing on the predictability of subsequent adverse outcomes within 5 years. We used the US-CD, which was calculated using multiple US findings. Predictive variables were assessed using Cox proportional hazards regression analysis, and the predictive value was evaluated using receiver operating characteristic curves.

RESULTS

Seventy-three patients were included. During a median follow-up of 1,441 days (range, 41-1,825 days), 16.4% (12/73) experienced clinical relapse, 9.6% (7/73) required endoscopic balloon dilation (EBD), 58.9% (43/73) required enhanced treatment, and 20.5% (15/73) underwent surgery. In the multivariate analysis, US-CD was significantly associated with clinical relapse (P= 0.038) and the need for enhanced treatment (P= 0.005). The area under the receiver operating characteristic curve for predicting clinical relapse and the need for EBD was 0.77 and 0.81, respectively, with US-CD (cutoff value = 11), and that for requiring enhanced treatment was 0.74 with US-CD (cutoff value = 6). Patients with US-CD ≥ 11 demonstrated a significantly higher occurrence of clinical relapse (P= 0.001) and EBD (P= 0.002) within 5 years. Patients with US-CD ≥ 6 experienced a significantly higher likelihood of requiring enhanced treatment (P< 0.001) within 5 years.

CONCLUSIONS

High US-CD is associated with subsequent adverse outcomes in patients with CD.

LAVA HyperSense and deep-learning reconstruction for near-isotropic (3D) enhanced magnetic resonance enterography in patients with Crohn's disease: utility in noise reduction and image quality improvement

PURPOSE

This study aimed to compare near-isotropic contrast-enhanced T1-weighted (CE-T1W) magnetic resonance enterography (MRE) images reconstructed with vendor-supplied deep-learning reconstruction (DLR) with those reconstructed conventionally in terms of image quality.

METHODS

A total of 35 patients who underwent MRE for Crohn's disease between August 2021 and February 2022 were included in this retrospective study. The enteric phase CE-T1W MRE images of each patient were reconstructed with conventional reconstruction and no image filter (original), with conventional reconstruction and image filter (filtered), and with a prototype version of AIRTM Recon DL 3D (DLR), which were then reformatted into the axial plane to generate six image sets per patient. Two radiologists independently assessed the images for overall image quality, contrast, sharpness, presence of motion artifacts, blurring, and synthetic appearance for qualitative analysis, and the signal-to-noise ratio (SNR) was measured for quantitative analysis.

RESULTS

The mean scores of the DLR image set with respect to overall image quality, contrast, sharpness, motion artifacts, and blurring in the coronal and axial images were significantly superior to those of both the filtered and original images (P < 0.001). However, the DLR images showed a significantly more synthetic appearance than the other two images (P < 0.05). There was no statistically significant difference in all scores between the original and filtered images (P > 0.05). In the quantitative analysis, the SNR was significantly increased in the order of original, filtered, and DLR images (P < 0.001).

CONCLUSION

Using DLR for near-isotropic CE-T1W MRE improved the image quality and increased the SNR.

The Role of Magnetic Resonance Enterography in Crohn’s Disease: A Review of Recent Literature

Inflammatory bowel disease (IBD) is the term used to identify a form of chronic inflammation of the gastrointestinal tract that primarily contemplates two major entities: ulcerative colitis (UC) and Crohn’s disease (CD). The classic signs are abdominal pain and diarrhoea that correlate with the localization of gastro-enteric disease, although in this pathology extraintestinal symptoms may coexist. The diagnosis of CD relies on a synergistic combination of clinical, laboratory (stool and biochemical), cross-sectional imaging evaluation, as well as endoscopic and histologic assessments. The purpose of this paper is to prove the role of imaging in the diagnosis and follow-up of patients with CD with particular focus on recent innovations of magnetic resonance enterography (MRE) as a pivotal diagnostic tool, analysing the MRE study protocol and imaging features during the various phases of disease activity and its complications.

Comparison of Sensitivity Encoding (SENSE) and Compressed Sensing-SENSE for Contrast-Enhanced T1-Weighted Imaging in Patients With Crohn Disease Undergoing MR Enterography

Please see the Editorial Comment by Tyler J. Fraum discussing this article. Background: Long acquisition times for breath-hold contrast-enhanced T1-weighted (CE-T1W) imaging in MR enterography (MRE) protocols result in reduced image quality. Objective: To compare CE-T1W imaging performed using sensitivity encoding (SENSE) and compressed-sensing SENSE (CS-SENSE) in terms of image quality and diagnostic performance for active inflammation in Crohn disease (CD). Methods: This retrospective study included 41 patients (31 men, 10 women; mean age, 34±12 years) who underwent MRE for known or suspected CD between June 2020 and September 2020. MRE was performed in one of two scanning rooms based on scheduling availability. Per institutional protocol, in one room, the enteric phase was acquired using SENSE (acceleration factor 3), and the portal phase was acquired using CS-SENSE (acceleration factor 5); this order was reversed in the other room. Two radiologists independently assessed sequences for subjective image quality measures at the patient level and for active inflammation at the bowel-segment level. Mean image quality scores between readers were computed. Diagnostic performance for active inflammation was compared using generalized estimating equations; a separate experienced radiologist reviewed the full MRE protocol to establish the reference standard. Results: The mean acquisition time of CE-T1W imaging was 17.2 ± 1.1 seconds for SENSE versus 11.5 ± 0.8 seconds for CS-SENSE (P<.001). CS-SENSE was significantly better than SENSE in overall image quality (4.2±0.7 vs 3.7±1.1; P=.02), motion artifacts (4.0±0.8 vs 3.6±1.2; P=.006), and aliasing artifacts (4.8±0.4 vs 4.2±0.6; P<.001). CSSENSE was significantly worse than SENSE in synthetic appearance (4.6±0.5 vs 4.8±0.4; P=.003). Contrast, sharpness, and blurring were not different between sequences (P>.05). For reader 1, CS-SENSE, compared with SENSE, demonstrated sensitivity of 86% versus 81% (P=.09), specificity of 88% versus 83% (P=.08), and accuracy of 87% versus 82% (P=.56). For reader 2, CS-SENSE, compared with SENSE, demonstrated sensitivity of 92% versus 80% (P=.006), specificity of 91% versus 98% (P=.16), and accuracy of 91% versus 86% (P=.002). Conclusion: Use of CS-SENSE for CE-T1W imaging in MRE protocols results in reduced scan times with reduced artifact and improved image quality. Clinical impact: The benefits of CS-SENSE in MRE protocols may improve the diagnostic performance for active inflammation in CD.

Evaluation of Crohn's Disease Activity: Development of an Ultrasound Score in a Multicenter Study

OBJECTIVE

Our goal in this multicentric prospective study was 2-fold: first, to test the diagnostic accuracy of ultrasound, color Doppler imaging (CDI), and contrast-enhanced ultrasound (CEUS) in identifying disease activity in patients with Crohn's disease (CD) compared with endoscopy as the reference standard; and, second, to construct a sonographic score that allows disease activity to be detected.

MATERIALS AND METHODS

Seventy-two patients with CD from 3 hospitals underwent within a 30-day period both colonoscopy and ultrasound (US), including mural thickness, CDI, and CEUS, prospectively as part of clinical care. A multivariate analysis was carried out to assess the influence of each of the ultrasound variables in predicting endoscopic activity. We then developed a predictive ultrasound score for disease activity, and a receiver operating characteristic (ROC) curve was constructed to determine the area under the ROC curve (AUC) and the best cut-off score value to discriminate between active and inactive disease.

RESULTS

Sonographic findings that were independent predictors of the presence of active disease at endoscopy were wall thickness, color grade, and contrast parameters. A score based on those variables showed high accuracy in predicting active disease, with an area under the ROC curve of 0.972. A simpler index, without contrast parameters, also showed high accuracy in detecting disease activity (AUC, 0.923).

CONCLUSION

A score based on wall thickness, color Doppler grade, and contrast parameters showed high accuracy in predicting active disease. A score without including the use of contrast agent had practically similar results and is easier to use in monitoring response to treatment.

Dynamic contrast-enhanced magnetic resonance imaging and diffusion-weighted imaging in the activity staging of terminal ileum Crohn's disease

BACKGROUND

The activity staging of Crohn’s disease (CD) in the terminal ileum is critical in developing an accurate clinical treatment plan. The activity of terminal ileum CD is associated with the microcirculation of involved bowel walls. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and diffusion-weighted imaging (DWI) can reflect perfusion and permeability of bowel walls by providing microcirculation information. As such, we hypothesize that DCE-MRI and DWI parameters can assess terminal ileum CD, thereby providing an opportunity to stage CD activity.

AIM

To evaluate the value of DCE-MRI and DWI in assessing activity of terminal ileum CD.

METHODS

Forty-eight patients with CD who underwent DCE-MRI and DWI were enrolled. The patients’ activity was graded as remission, mild and moderate-severe. The transfer constant (K^trans), wash-out constant (K_ep), and extravascular extracellular volume fraction (V_e) were calculated from DCE-MRI and the apparent diffusion coefficient (ADC) was obtained from DWI. Magnetic Resonance Index of Activity (MaRIA) was calculated from magnetic resonance enterography. Differences in these quantitative parameters were compared between normal ileal loop (NIL) and inflamed terminal ileum (ITI) and among different activity grades. The correlations between these parameters, MaRIA, the Crohn’s Disease Activity Index (CDAI), and Crohn’s Disease Endoscopic Index of Severity (CDEIS) were examined. Receiver operating characteristic curve analyses were used to determine the diagnostic performance of these parameters in differentiating between CD activity levels.

RESULTS

Higher K^trans (0.07 ± 0.04 vs 0.01 ± 0.01), K_ep (0.24 ± 0.11 vs 0.15 ± 0.05) and V_e (0.27 ± 0.07 vs 0.08 ± 0.03), but lower ADC (1.41 ± 0.26 vs 2.41 ± 0.30) values were found in ITI than in NIL (all P < 0.001). The K^trans, K_ep, V_e and MaRIA increased with disease activity, whereas the ADC decreased (all P < 0.001). The K^trans, K_ep, V_e and MaRIA showed positive correlations with the CDAI (r = 0.866 for K^trans, 0.870 for K_ep, 0.858 for V_e, 0.890 for MaRIA, all P < 0.001) and CDEIS (r = 0.563 for K^trans, 0.567 for K_ep, 0.571 for V_e, 0.842 for MaRIA, all P < 0.001), while the ADC showed negative correlations with the CDAI (r = -0.857, P < 0.001) and CDEIS (r = -0.536, P < 0.001). The areas under the curve (AUC) for the K^trans, K_ep, V_e, ADC and MaRIA values ranged from 0.68 to 0.91 for differentiating inactive CD (CD remission) from active CD (mild to severe CD). The AUC when combining the K^trans, K_ep and V_e was 0.80, while combining DCE-MRI parameters and ADC values yielded the highest AUC of 0.95.

CONCLUSION

DCE-MRI and DWI parameters all serve as measures to stage CD activity. When they are combined, the assessment performance is improved and better than MaRIA.

Magnetic resonance enterography compared with ultrasonography in newly diagnosed and relapsing Crohn's disease patients: the METRIC diagnostic accuracy study

BACKGROUND

Magnetic resonance enterography and enteric ultrasonography are used to image Crohn's disease patients. Their diagnostic accuracy for presence, extent and activity of enteric Crohn's disease was compared.

OBJECTIVE

To compare diagnostic accuracy, observer variability, acceptability, diagnostic impact and cost-effectiveness of magnetic resonance enterography and ultrasonography in newly diagnosed or relapsing Crohn's disease.

DESIGN

Prospective multicentre cohort study.

SETTING

Eight NHS hospitals.

PARTICIPANTS

Consecutive participants aged ≥ 16 years, newly diagnosed with Crohn's disease or with established Crohn's disease and suspected relapse.

INTERVENTIONS

Magnetic resonance enterography and ultrasonography.

MAIN OUTCOME MEASURES

The primary outcome was per-participant sensitivity difference between magnetic resonance enterography and ultrasonography for small bowel Crohn's disease extent. Secondary outcomes included sensitivity and specificity for small bowel Crohn's disease and colonic Crohn's disease extent, and sensitivity and specificity for small bowel Crohn's disease and colonic Crohn's disease presence; identification of active disease; interobserver variation; participant acceptability; diagnostic impact; and cost-effectiveness.

RESULTS

Out of the 518 participants assessed, 335 entered the trial, with 51 excluded, giving a final cohort of 284 (133 and 151 in new diagnosis and suspected relapse cohorts, respectively). Across the whole cohort, for small bowel Crohn's disease extent, magnetic resonance enterography sensitivity [80%, 95% confidence interval (CI) 72% to 86%] was significantly greater than ultrasonography sensitivity (70%, 95% CI 62% to 78%), with a 10% difference (95% CI 1% to 18%; p = 0.027). For small bowel Crohn's disease extent, magnetic resonance enterography specificity (95%, 95% CI 85% to 98%) was significantly greater than ultrasonography specificity (81%, 95% CI 64% to 91%), with a 14% difference (95% CI 1% to 27%). For small bowel Crohn's disease presence, magnetic resonance enterography sensitivity (97%, 95% CI 91% to 99%) was significantly greater than ultrasonography sensitivity (92%, 95% CI 84% to 96%), with a 5% difference (95% CI 1% to 9%). For small bowel Crohn's disease presence, magnetic resonance enterography specificity was 96% (95% CI 86% to 99%) and ultrasonography specificity was 84% (95% CI 65% to 94%), with a 12% difference (95% CI 0% to 25%). Test sensitivities for small bowel Crohn's disease presence and extent were similar in the two cohorts. For colonic Crohn's disease presence in newly diagnosed participants, ultrasonography sensitivity (67%, 95% CI 49% to 81%) was significantly greater than magnetic resonance enterography sensitivity (47%, 95% CI 31% to 64%), with a 20% difference (95% CI 1% to 39%). For active small bowel Crohn's disease, magnetic resonance enterography sensitivity (96%, 95% CI 92% to 99%) was significantly greater than ultrasonography sensitivity (90%, 95% CI 82% to 95%), with a 6% difference (95% CI 2% to 11%). There was some disagreement between readers for both tests. A total of 88% of participants rated magnetic resonance enterography as very or fairly acceptable, which is significantly lower than the percentage (99%) of participants who did so for ultrasonography. Therapeutic decisions based on magnetic resonance enterography alone and ultrasonography alone agreed with the final decision in 122 out of 158 (77%) cases and 124 out of 158 (78%) cases, respectively. There were no differences in costs or quality-adjusted life-years between tests.

LIMITATIONS

Magnetic resonance enterography and ultrasonography scans were interpreted by practitioners blinded to clinical data (but not participant cohort), which does not reflect use in clinical practice.

CONCLUSIONS

Magnetic resonance enterography has higher accuracy for detecting the presence, extent and activity of small bowel Crohn's disease than ultrasonography does. Both tests have variable interobserver agreement and are broadly acceptable to participants, although ultrasonography produces less participant burden. Diagnostic impact and cost-effectiveness are similar. Recommendations for future work include investigation of the comparative utility of magnetic resonance enterography and ultrasonography for treatment response assessment and investigation of non-specific abdominal symptoms to confirm or refute Crohn's disease.

TRIAL REGISTRATION

Current Controlled Trials ISRCTN03982913.

FUNDING

This project was funded by the National Institute for Health Research (NIHR) Health Technology Assessment programme and will be published in full in Health Technology Assessment; Vol. 23, No. 42. See the NIHR Journals Library website for further project information.

Magnetic resonance enterography

Crohn's disease is a condition of chronic inflammation that may involve any part of the gastrointestinal tract, although it more frequently affects the terminal ileum. Longstanding inflammation may lead to several bowel complications including obstruction, stricture, fistula and abscesses which often necessitate surgery. Cross-sectional imaging methods such as computed tomography and magnetic resonance imaging are being utilized more frequently to assess mural and extramural inflammatory bowel disease manifestations. Magnetic resonance enterography (MRE) for assessment of small bowel is optimal because of absence of ionizing radiation, better soft tissue contrast, development of motion-free sequences and high resolution images. A typical protocol includes pre and postcontrast sequences utilizing an enteric contrast agent for adequate bowel distention and an antiperistaltic agent. Overall, MRE allows the evaluation of disease activity, extraenteric complication and response to therapy with a great impact on patient management. In this review we discuss the features of MRE from patient's preparation and exam protocol to pathological findings.

Utility of MR Imaging in Abdominopelvic Emergencies

Acute abdominopelvic pain, a common symptom in emergency department patients, is challenging given the spectrum of differential diagnoses encompassing multiple organ systems, ranging from benign self-limiting to life-threatening and emergent. Diagnostic imaging is critical given its high accuracy and management guidance. A contrast-enhanced computed tomography (CT) scan is preferred given its widespread availability and speed of acquisition. MR imaging may be appropriate, usually performed for specific indications with tailored protocols. It is accurate for diagnosis and may be an alternative to CT. This article discusses the advantages and disadvantages, protocols, and appearances of MR imaging of common diagnoses.

Comparison of contrast-enhanced and diffusion-weighted MRI in assessment of the terminal ileum in Crohn's disease patients

PURPOSE

The purpose of the study was to compare the performance of contrast-enhanced (CE)-MRI and diffusion-weighted imaging (DW)-MRI in grading Crohn's disease activity of the terminal ileum.

METHODS

Three readers evaluated CE-MRI, DW-MRI, and their combinations (CE/DW-MRI and DW/CE-MRI, depending on which protocol was used at the start of evaluation). Disease severity grading scores were correlated to the Crohn's Disease Endoscopic Index of Severity (CDEIS). Diagnostic accuracy, severity grading, and levels of confidence were compared between imaging protocols and interobserver agreement was calculated.

RESULTS

Sixty-one patients were included (30 female, median age 36). Diagnostic accuracy for active disease for CE-MRI, DW-MRI, CE/DW-MRI, and DW/CE-MRI ranged between 0.82 and 0.85, 0.75 and 0.83, 0.79 and 0.84, and 0.74 and 0.82, respectively. Severity grading correlation to CDEIS ranged between 0.70 and 0.74, 0.66 and 0.70, 0.69 and 0.75, and 0.67 and 0.74, respectively. For each reader, CE-MRI values were consistently higher than DW-MRI, albeit not significantly. Confidence levels for all readers were significantly higher for CE-MRI compared to DW-MRI (P < 0.001). Further increased confidence was seen when using combined imaging protocols.

CONCLUSIONS

There was no significant difference of CE-MRI and DW-MRI in determining disease activity, but the higher confidence levels may favor CE-MRI. DW-MRI is a good alternative in cases with relative contraindications for the use of intravenous contrast medium.

Anoperineal lesions in Crohn's disease: French recommendations for clinical practice

BACKGROUND

Anoperineal lesion (APL) occurrence is a significant event in the evolution of Crohn's disease (CD). Management should involve a multidisciplinary approach combining the knowledge of the gastroenterologist, the colorectal surgeon and the radiologist who have appropriate experience in this area. Given the low level of evidence of available medical and surgical strategies, the aim of this work was to establish a French expert consensus on management of anal Crohn's disease. These recommendations were led under the aegis of the Société Nationale Française de Colo-Proctologie (SNFCP). They report a consensus on the management of perianal Crohn's disease lesions, including fistulas, ulceration and anorectal stenosis and propose an appropriate treatment strategy, as well as sphincter-preserving and multidisciplinary management.

METHODOLOGY

A panel of French gastroenterologists and colorectal surgeons with expertise in inflammatory bowel diseases reviewed the literature in order to provide practical management pathways for perianal CD. Analysis of the literature was made according to the recommendations of the Haute Autorité de Santé (HAS) to establish a level of proof for each publication and then to propose a rank of recommendation. When lack of factual data precluded ranking according to the HAS, proposals based on expert opinion were written. Therefore, once all the authors agreed on a consensual statement, it was then submitted to all the members of the SNFCP. As initial literature review stopped in December 2014, more recent European or international guidelines have been published since and were included in the analysis.

RESULTS

MRI is recommended for complex secondary lesions, particularly after failure of previous medical and/or surgical treatments. For severe anal ulceration in Crohn's disease, maximal medical treatment with anti-TNF agent is recommended. After prolonged drainage of simple anal fistula by a flexible elastic loop or loosely tied seton, and after obtaining luminal and perineal remission by immunosuppressive therapy and/or anti-TNF agents, the surgical treatment options to be discussed are simple seton removal or injection of the fistula tract with biological glue. After prolonged loose-seton drainage of the complex anal fistula in Crohn's disease, and after obtaining luminal and perineal remission with anti-TNF ± immunosuppressive therapy, surgical treatment options are simple removal of seton and rectal advancement flap. Colostomy is indicated as a last option for severe APL, possibly associated with a proctectomy if there is refractory rectal involvement after failure of other medical and surgical treatments. The evaluation of anorectal stenosis of Crohn's disease (ARSCD) requires a physical examination, sometimes under anesthesia, plus endoscopy with biopsies and MRI to describe the stenosis itself, to identify associated inflammatory, infectious or dysplastic lesions, and to search for injury or fibrosis of the sphincter. Therapeutic strategy for ARSCD requires medical-surgical cooperation.

Accuracy of magnetic resonance enterography in the preoperative assessment of patients with Crohn's disease of the small bowel

AIM

To assess the accuracy of magnetic resonance enterography in predicting the extension, location and characteristics of the small bowel segments affected by Crohn's disease.

METHOD

This is a prospective study including a consecutive series of 38 patients with Crohn's disease of the small bowel who underwent surgery at a specialized colorectal unit of a tertiary hospital. Preoperative magnetic resonance enterography was performed in all patients, following a homogeneous protocol, within the 3 months prior to surgery. A thorough exploration of the small bowel was performed during the surgical procedure; calibration spheres were used according to the discretion of the surgeon. The accuracy of magnetic resonance enterography in detecting areas affected by Crohn's disease in the small bowel was assessed. The findings of magnetic resonance enterography were compared with surgical and pathological findings.

RESULTS

Thirty-eight patients with 81 lesions were included in the study. During surgery, 12 lesions (14.8%) that were not described on magnetic resonance enterography were found. Seven of these were detected exclusively by the use of calibration spheres, passing unnoticed at surgical exploration. Magnetic resonance enterography had 90% accuracy in detecting the location of the stenosis (75.0% sensitivity, 95.7% specificity). Magnetic resonance enterography did not precisely diagnose the presence of an inflammatory phlegmon (accuracy 46.2%), but it was more accurate in detecting abscesses or fistulas (accuracy 89.9% and 98.6%, respectively).

CONCLUSION

Magnetic resonance enterography is a useful tool in the preoperative assessment of patients with Crohn's disease. However, a thorough intra-operative exploration of the entire small bowel is still necessary.

The first joint ESGAR/ ESPR consensus statement on the technical performance of cross-sectional small bowel and colonic imaging

Objectives

To develop guidelines describing a standardised approach to patient preparation and acquisition protocols for magnetic resonance imaging (MRI), computed tomography (CT) and ultrasound (US) of the small bowel and colon, with an emphasis on imaging inflammatory bowel disease.

Methods

An expert consensus committee of 13 members from the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) and European Society of Paediatric Radiology (ESPR) undertook a six-stage modified Delphi process, including a detailed literature review, to create a series of consensus statements concerning patient preparation, imaging hardware and image acquisition protocols.

Results

One hundred and fifty-seven statements were scored for agreement by the panel of which 129 statements (82 %) achieved immediate consensus with a further 19 (12 %) achieving consensus after appropriate modification. Nine (6 %) statements were rejected as consensus could not be reached.

Conclusions

These expert consensus recommendations can be used to help guide cross-sectional radiological practice for imaging the small bowel and colon.

Key points

• Cross-sectional imaging is increasingly used to evaluate the bowel

• Image quality is paramount to achieving high diagnostic accuracy

• Guidelines concerning patient preparation and image acquisition protocols are provided

Diagnostic imaging advances in murine models of colitis

Inflammatory bowel diseases (IBD) such as Crohn’s disease and ulcerative colitis are chronic-remittent inflammatory disorders of the gastrointestinal tract still evoking challenging clinical diagnostic and therapeutic situations. Murine models of experimental colitis are a vital component of research into human IBD concerning questions of its complex pathogenesis or the evaluation of potential new drugs. To monitor the course of colitis, to the present day, classical parameters like histological tissue alterations or analysis of mucosal cytokine/chemokine expression often require euthanasia of animals. Recent advances mean revolutionary non-invasive imaging techniques for in vivo murine colitis diagnostics are increasingly available. These novel and emerging imaging techniques not only allow direct visualization of intestinal inflammation, but also enable molecular imaging and targeting of specific alterations of the inflamed murine mucosa. For the first time, in vivo imaging techniques allow for longitudinal examinations and evaluation of intra-individual therapeutic response. This review discusses the latest developments in the different fields of ultrasound, molecularly targeted contrast agent ultrasound, fluorescence endoscopy, confocal laser endomicroscopy as well as tomographic imaging with magnetic resonance imaging, computed tomography and fluorescence-mediated tomography, discussing their individual limitations and potential future diagnostic applications in the management of human patients with IBD.

Magnetic resonance enterography or video capsule endoscopy - what do Crohn's disease patients prefer?

BACKGROUND

Despite differences in the information obtained by capsule endoscopy (CE) and magnetic resonance enterography (MRE), one of these modalities is usually needed when evaluating disease activity. There are no data on patients' preference that would help guide the choice between these two modalities in these instances.

AIM

To compare patients' tolerance and preference to MRE versus CE.

PATIENTS AND METHODS

Patients with known small bowel Crohn's disease (CD) in clinical remission (Crohn's disease activity index [CDAI] <150) or with mild symptoms (CDAI <220) were prospectively recruited. All patients underwent MRE followed by CE. Patients were asked to fill out a questionnaire addressing specific points regarding inconvenience during the preparation for the procedures, the procedures, and postprocedures. Side effects and procedure preference were addressed. Questionnaires were included for analysis only when more than 95% of the items were addressed.

RESULTS

Fifty-six patients fulfilled inclusion criteria. Pre-exam discomfort, during-exam discomfort, nausea, vomiting, bloating, and abdominal pain were all significantly more prominent in MRE as compared to CE (P<0.0001, P<0.0001, P<0.0001, P=0.009, P=0.0002, P<0.0001, respectively). MRE was perceived as a more difficult procedure (P<0.0001). Furthermore, MRE was associated with a specific adverse event - claustrophobia. Seventy-eight percent of patients (44 patients) preferred to repeat CE as compared to 22% (P<0.0001) who preferred MRE.

CONCLUSION

CE was better tolerated by CD patients compared to MRE and was preferred by 78% of patients. The superior tolerability of CE should be considered along with the diagnostic features, and more data sought when choosing between these two modalities for CD patients for long-term follow-up.

Pediatric Magnetic Resonance Enterography: Focused on Crohn's Disease

Crohn's disease is a chronic idiopathic inflammatory disease of the intestines characterized by frequent relapse and remission. It often develops in children and adolescents, who are vulnerable to repeated exposure to ionizing radiations. Magnetic resonance enterography (MRE) is an increasingly important radiation-free imaging modality that is used to evaluate pediatric patients with Crohn's disease. MRE can evaluate extraluminal and extraintestinal abnormalities as well as the status of the bowel wall. In addition, MRE has an advantage in the evaluation of the small bowel involvement. MRE can be used for the initial diagnosis of Crohn's disease, and can aid in the assessment of disease activity and complications such as penetrating and fibrostenotic diseases. The aims of this article are to review the MRE technique for obtaining diagnostic and high-quality images and to discuss interpretations of imaging findings in patients with Crohn's disease.

Detection of Crohn disease lesions of the small and large bowel in pediatric patients: diagnostic value of MR enterography versus reference examinations

OBJECTIVE

The purpose of this article is to prospectively determine the accuracy of MR enterography in detecting Crohn disease lesions from the jejunum to the anorectal region in pediatric patients, in comparison with main reference investigations.

SUBJECTS AND METHODS

Fifty consecutive children with known Crohn disease underwent MR enterography with oral contrast agent and gadolinium-chelate intravenous injection. Two radiologists detected and localized lesions by dividing the bowel into nine segments (450 analyzed segments in 50 patients). Ileocolonoscopy, barium studies, intestinal ultrasound, and capsule endoscopy were considered as first- and second-level reference examinations and were performed within 15 days of MR enterography.

RESULTS

MR enterography detected lesions in 164 of 450 segments, with 155 true-positive and nine false-positive findings; overall sensitivity, specificity, and positive and negative predictive values for small- and large-bowel lesions were 94.5%, 97%, 94.5%, and 97%, respectively (ĸ = 0.93; 95% CI, 0.89-0.97). Sensitivity and specificity values were 88% and 97%, respectively, for the jejunum, 100% and 97% for the proximal-to-mid ileum, 100% and 100% for the distal ileum, 93% and 100% for the cecum, 70% and 97% for the ascending colon, 80% and 100% for the transverse colon, 100% and 92% for the descending colon, 96% and 90% for the sigmoid colon, and 96% and 88% for the rectum. From jejunum to rectum, the AUC value ranged between 0.916 (jejunum) and 1.00 (distal ileum). Perianal fistulas were diagnosed in 15 patients, and other complications were found in 13 patients.

CONCLUSION

MR enterography showed an accuracy comparable to that of reference investigations, for both small- and large-bowel lesions. Because MR enterography is safer and more comprehensive than the reference examinations, it should be considered the primary examination for detecting Crohn disease lesions in children.

Utility of the diffusion-weighted imaging for activity evaluation in Crohn's disease patients underwent magnetic resonance enterography

Background

Cross-sectional imaging techniques as magnetic resonance enterography (MRE) may offer additional information on transmural inflammation, stricturing and fistulising complications in Crohn’s disease (CD). The purpose of our study was to evaluate the diagnostic accuracy of Magnetic Resonance Imaging (MRI) combined with Diffusion-weighted Imaging (DWI) and MRE for determination of inflammation in small bowel CD.

Methods

MR imaging examination was performed with a GE Signa EXCITE 3.0 T MRI scanner. The optimal b value in DWI with a learning cohort of patients was determined. The diagnostic accuracy for active lesions and disease activity were accessed by MRE combined with DWI.

Results

The b value 800 s/mm² group showed the highest diagnostic sensitivity (74.19%) for diagnostic assessment of active Crohn’s lesions on DWI. MRE combined with DWI showed the highest sensitivity (93.55%), specificity (89.47%) and diagnostic accuracy (92%) compared with MRE or DWI alone. The segmental MR score (MR-score-S) showed a significantly positive correlation with the Capsule Endoscopy Crohn’s Disease Activity Index Score (CECDAI-S) (r = 0.717, p < 0.01). The total MR score (MR-score-T) showed significant association with C-reactive protein (CRP) (r = 0.445, p = 0.019) and erythrocyte sedimentation rate (ESR) (r = 0.688, p < 0.01).

Conclusions

MRE combined with DWI improves the diagnostic accuracy for active lesions and correlates the endoscopic disease activity. MRE with DWI could represent a non-invasive tool in assessing active inflammation in CD.

Contrast-enhanced ultrasound in the diagnosis of patients suspected of having active Crohn's disease: meta-analysis

This meta-analysis was aimed at assessing the performance of oral/microbubble contrast-enhanced ultrasound (CEUS) in the detection of active Crohn's disease (CD). A literature search of PubMed, Medline, the China National Knowledge Infrastructure and the Cochrane Library was conducted. Published articles that evaluated the diagnostic potency of CEUS in CD were included in the study. A total of eight articles, which included 428 patients, were finally analyzed. Sensitivity, specificity, positive likelihood ratio, negative likelihood ratio and area under the curve were calculated to examine the diagnostic accuracy of CEUS. The pooled sensitivity and specificity of CEUS for active CD were 93% (95% confidence interval: 89%-95%) and 87% (81%-91%), respectively. The summary diagnostic odds ratio was 80.35 (30.93-208.73), and the area under the curve was 0.9633. In conclusion, this meta-analysis pooled results from previous studies to evaluate the accuracy of CEUS in the detection of CD. We found that CEUS has high accuracy in the detection of active CD using endoscopy/biopsy or clinical index as the reference standard. In the future, CEUS may also be widely used in other diseases, reducing the necessity for invasive diagnostic procedure.

An overview of magnetic resonance enterography for Crohn's disease

Magnetic resonance enterography (MRE) is a relatively new imaging modality that has shown promise for diagnosing, staging, and monitoring Crohn's disease (CD) and its complications while avoiding exposure to ionizing radiation. In addition to clinical implications, MRE has the potential to be used as an objective measure of disease activity for clinical trials. We provide the rationale for MRE, indications for its use, and an overview of the typical procedure and common findings for institutions who want to begin or refine the use of MRE for CD.

Gastrointestinal imaging-practical magnetic resonance imaging approach

Over the past two decades, advances in cross-sectional imaging such as computed tomography and magnetic resonance imaging (MRI) have dramatically changed the concept of gastrointestinal imaging. MR is playing an increasing role in the evaluation of gastrointestinal disorders. MRI combines the advantages of excellent soft-tissue contrast, noninvasiveness, functional information and lack of ionizing radiation. Furthermore, recent developments of MRI have led to improved spatial and temporal resolution as well as decreased motion artifacts. In this article we describe the technical aspects of gastrointestinal MRI and present a practical approach for a well-known spectrum of gastrointestinal disease processes.

Comparison of magnetic resonance and balloon enteroscopic examination of the small intestine in patients with Crohn's disease

BACKGROUND & AIMS

Magnetic resonance (MR) enterography is a recommended imaging technique for detecting intestinal involvement in Crohn's disease (CD). However, the diagnostic accuracy of MR enterography has not been compared directly what that of enteroscopy of the jejunum and proximal ileum. We evaluated the usefulness of MR enterocolonography (MREC) by comparing its findings with those from balloon-assisted enteroscopy.

METHODS

In a prospective study, MREC and enteroscopy were performed within 3 days of each other on 100 patients. Ulcerative lesions and all mucosal lesions were evaluated. Physicians and radiologists were blinded to results from other studies. Findings from MREC were compared directly with those from enteroscopy; the sensitivity and specificity with which MREC detected CD lesions were assessed.

RESULTS

MREC detected ulcerative lesions and all mucosal lesions in the small intestine with 82.4% sensitivity (95% confidence interval [CI], 75.4%-87.7%) and 67.5% sensitivity (95% CI, 63.1%-70.0%); specificity values were 87.6% (95% CI, 83.7%-90.6%) and 94.8% (95% CI, 90.1%-97.5%). MREC detected major stenosis with 58.8% sensitivity (95% CI, 37.6%-77.2%) and 90.0% specificity (95% CI, 88.4%-91.5%) and all stenoses with 40.8% sensitivity (95% CI, 30.8%-49.4%) and 93.7% specificity (95% CI, 91.1%-95.9%).

CONCLUSIONS

MREC is useful for detecting active lesions in the small intestine. However, MR imaging is less sensitive for detecting intestinal damage, such as stenoses. Enteroscopy is preferred for identifying intestinal damage. Suitable imaging approaches should be selected to assess CD lesions in deep small intestine.

Intestinal lesions in pediatric Crohn disease: comparative detectability among pulse sequences at MR enterography

BACKGROUND

Variable sequences can be used in MR enterography, and no consensus exists for the best protocol in children with Crohn disease.

OBJECTIVE

To compare the lesion detectability of various MR enterography sequences and to correlate the findings of these sequences with the Pediatric Crohn's Disease Activity Index (PCDAI) in children with Crohn disease.

MATERIALS AND METHODS

Children with clinically or pathologically confirmed Crohn disease underwent MR enterography, including a single-shot fast spin-echo (SSFSE) sequence, motility imaging (coronal 2-D balanced fast field echo), diffusion-weighted imaging (DWI), and dynamic contrast enhancement imaging (including arterial, portal and delayed phases). The lesion detectability of each sequence was graded 0-2 for each involved bowel segment. The lesion detectability and PCDAI result on different sequences were compared using the weighted least squares method and Student's t-test, respectively.

RESULTS

Fifteen children (11 boys, 4 girls, mean age 13.7 ± 1.4 years) with a total of 41 lesions were included in this study. All lesions detected in more than two sequences were visible on the single-shot fast spin-echo (SSFSE) sequence. The relative lesion detection rate was 78.1% on motility imaging, 90.2% on DWI, and 92.7% on arterial, 95.1% on portal and 95.1% on delayed phase imaging. Compared to the SSFSE sequence, motility imaging (P < 0.001) and DWI (P = 0.039) demonstrated lower detectability. The mean PCDAI result in the detected lesions was statistically higher only on dynamic enhancement imaging (P < 0.001).

CONCLUSION

All MR enterography sequences were found to have relatively high lesion detectability in children with Crohn disease, while motility imaging showed the lowest lesion detectability. Lesions detected on dynamic enhancement imaging showed a higher PCDAI result, which suggests that this sequence is specific for active inflammation.

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.

Evolving role of MRI in Crohn's disease

MR enterography is playing an evolving role in the evaluation of small bowel Crohn's disease (CD). Standard MR enterography includes a combination of rapidly acquired T2 sequence, balanced steady-state acquisition, and contrast enhanced T1-weighted gradient echo sequence. The diagnostic performance of these sequences has been shown to be comparable, and in some respects superior, to other small bowel imaging modalities. The findings of CD on MR enterography have been well described in the literature. New and emerging techniques such as diffusion-weighted imaging (DWI), dynamic contrast enhanced MRI (DCE-MRI), cinematography, and magnetization transfer, may lead to improved accuracy in characterizing the disease. These advanced techniques can provide quantitative parameters that may prove to be useful in assessing disease activity, severity, and response to treatment. In the future, MR enterography may play an increasing role in management decisions for patients with small bowel CD; however, larger studies are needed to validate these emerging MRI parameters as imaging biomarkers.

CT and MR enterography in evaluating small bowel diseases: when to use which modality?

MR and CT techniques optimized for small bowel imaging are playing an increasing role in the evaluation of small bowel disorders. Several studies have shown the advantages of these techniques over traditional barium fluoroscopic examinations due to improvements in spatial and temporal resolution combined with improved bowel distending agents. The preference of MR vs. CT has been geographical and based on expertise and public policy. With the increasing awareness of radiation exposure, there has been a more global interest in implementing techniques that either reduce or eliminate radiation exposure. This is especially important in patients with chronic diseases such as inflammatory bowel disease who may require multiple studies over a lifetime or in studies that require sequential imaging time points such as in assessment of gastrointestinal motility. MRI has many properties that make it well suited to imaging of the small bowel: the lack of ionizing radiation, the improved tissue contrast that can be obtained by using a variety of pulse sequences, and the ability to perform real time functional imaging. Moreover, MR modalities allow visualization of the entire bowel, without overlapping bowel loops, as well as the detection of both intra- and extraluminal abnormalities.The intra- and extraluminal MR findings, combined with contrast enhancement and functional information, help to make an accurate diagnosis and consequently characterize small bowel diseases.

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

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

Small Bowel Imaging: Clinical Applications of the Different Imaging Modalities—A Comprehensive Review

In the last years, MR and CT techniques have been optimized for small bowel imaging and are playing an increasing role in the evaluation of small bowel disorders. In comparison to traditional barium fluoroscopic examinations, spatial and temporal resolution is now much more improved partially thanks to modern bowel distending agents. However, there is a global interest in implementing techniques that either reduce or eliminate radiation exposure. This is especially important in patients with chronic diseases such as inflammatory bowel disease who may require multiple studies over a lifetime. Owing to the excellent soft tissue contrast, direct multiplanar imaging capabilities, new ultrafast breath-holding pulse sequences, lack of ionizing radiation, and availability of a variety of oral contrast agents, MR is well suited to play a critical role in the imaging of small bowel disorders.

Value of T2-weighted magnetic resonance imaging in the assessment of wall inflammation and fibrosis in Crohn's disease

This review focuses specifically on the diagnostic value of T2-weighted imaging in the assessment of Crohn's disease (CD) inflammation. In general, T2-weighted imaging has been less extensively investigated than T1-weighted gadolinium-enhanced imaging, even if it may offer similar information on disease activity. Furthermore, T2-weighted imaging allows CD characterization, which is crucial in the management of the disease when differentiating intestinal edema from fibrosis. Technical aspects, morphological findings and signs of active intestinal inflammation and fibrosis detectable on T2-weighted images will be reviewed and shown. Correlation between T2-weighted imaging findings, clinical activity indexes and histopathology features will be discussed. Since T2-weighted imaging is essential in the evaluation of CD activity, it should always complement with T1-weighted imaging, although it could also be used alone in the assessment of CD.

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.

MR imaging of the small bowel

Small-bowel radiology has undergone dramatic changes in the past 2 decades. Despite important recent advances in small-bowel endoscopy, radiologic imaging remains important for patients suspected of having or with established small-bowel disease. Cross-sectional imaging techniques (computed tomography and magnetic resonance [MR] imaging), used to investigate both extraluminal abnormalities and intraluminal changes, have gradually replaced barium contrast examinations, which are, however, still used to examine early mucosal disease. MR imaging techniques clearly highlight endoluminal, mural and extramural enteric details and provide vascular and functional information, thereby enhancing the diagnostic value of these techniques in small-bowel diseases. Two MR imaging based techniques are currently utilized: MR enteroclysis and MR enterography. In enteroclysis, enteric contrast material is administered through a nasoenteric tube, whereas in enterography, large volumes of enteric contrast material are administered orally. MR enteroclysis ensures consistently better luminal distention than does MR enterography in both the jejunum and the ileum and more accurately depicts endoluminal abnormalities and early disease, particularly at the level of the jejunal loops. Moreover, MR enteroclysis provides a high level of accuracy in the diagnosis and exclusion of small-bowel inflammatory and neoplastic diseases and can be used for the first radiologic evaluation, while MR enterography may effectively be used to follow up both Crohn disease patients without jejunal disease and in pediatric patients where nasogastric intubation might be a problem. MR enteroclysis may also reveal subtle transition points or an obstruction in the lower small bowel, which may escape detection when more routine methods, including enterography, are used. MR imaging offers detailed morphologic information and functional data of small-bowel diseases and provides reliable evidence of normalcy, thereby allowing the diagnosis of early or subtle structural abnormalities and guiding treatment and decisions in patient care.

Development of a numerical index quantitating small bowel damage as detected by ultrasonography in Crohn's disease

Small intestine contrast ultrasonography (SICUS) has emerged as a valuable tool in the detection of intestinal damage in Crohn's disease (CD). Our aim was to develop a numerical index quantitating small bowel damage as detected by SICUS in patients with an established diagnosis of CD. One hundred and ten patients with ileal or ileocolonic CD were prospectively enrolled and followed up for one year. Disease activity was assessed by CDAI and CRP levels. Study variables included bowel wall thickness, lumen diameter, lesion length and number of lesion site. Fistula, mesenteric adipose tissue alteration, abscess and lymphnodes were also considered. Bowel segments were considered as a hollow cylinder. Standardized variations of variables were combined into a statistical and mathematical model to create an algorithm scoring an index value ranging from 0 to 200. Index was subdivided into a severity scale with 5 classes from the lower (A) to the higher score (E). Median lesion index value was significantly higher (p<0.005) in patients with a CDAI>150 and in patients with CRP>5 mg/l (p=0.003). Patients classified in class E and D at SICUS underwent surgery within one year follow up more frequently than those in class C, B and A (p<0.0001). We propose a new index for assessment of small bowel lesions in CD (SLIC: sonographic lesion index for CD) developed by using SICUS. This index may turn ultrasonography in CD from a descriptive qualitative assessment to a quantitative numerical index suitable for comparison studies.

Differences in the location and activity of intestinal Crohn's disease lesions between adult and paediatric patients detected with MRI

OBJECTIVES

To prospectively compare paediatric patients (PP) and adult patients (AP) affected by Crohn's disease (CD) in terms of the location and activity of intestinal lesions.

METHODS

Forty-three children (mean age 15 years) and 43 adults (mean age 48 years) with proven CD underwent magnetic resonance enterography (MRE) to localise lesions and detect their activity in 9 segments of the small and large bowel. The results were analysed on a per patient and per segment basis. Ileo-colonoscopy was performed in all patients. P values less than 0.05 were considered statistically significant.

RESULTS

Involvement of terminal ileum was significantly different in the two groups: observed in 100 % of AP (43/43) versus 58 % (23/43) of PP (P < 0.0001). Conversely, the colon was diseased in 84 % of PP versus 64 % of AP. In particular, left colonic segments were significantly more involved in PP (descending colon 53 % versus 21 %, P < 0.01; rectum 67 % versus 23 %, P < 0.0001; sigmoid colon 56 % versus 37 %, not significant), whereas caecal involvement was equal in both groups. In children the maximal disease activity was found in left colonic segments, whereas in adults it was in the terminal ileum.

CONCLUSIONS

MRE detected significant differences between the two populations, showing a more extensive and severe involvement of the left colon in children but the distal ileum in adults.

KEY POINTS

• MRI is useful for assessing Crohn's disease in adult and paediatric patients. • Adult and paediatric patients show different intestinal involvement on MRI. • The distal ileum is maximally involved in adults vs. the left colon in children. • The causes of the severe left colonic disease in children are unknown. • The extensive colonic involvement in children has clinical-diagnostic implications.

Assessment of activity of Crohn's disease of the ileum and large bowel: proposal for a new multiparameter MR enterography score

PURPOSE

We evaluated the diagnostic accuracy of magnetic resonance enterography (MR-E) in assessing Crohn's disease (CD) activity by differentiating acute, chronic and remission stages of disease through a quantitative MR-E assessment.

MATERIALS AND METHODS

One hundred patients with a histological diagnosis of CD were studied with MR-E. Intestinal distension was obtained by oral administration of approximately 2 L of a polyethylene glycol solution (PEG). In all cases, the ileum and large bowel were imaged with morphological sequences (heavily T2-weighted single-shot, dual fast-field echo, balanced fast-field echo) and a postcontrast dynamic sequence (T1-weighted high-resolution isotropic volume excitation). Disease activity was assessed according to a multiparameter score (0-8) based on lesion morphology, signal intensity and contrast enhancement. MR-E findings were compared with clinical-laboratory data and disease activity indices [Crohn's Disease Activity Index (CDAI); Inflammatory Bowel Disease Questionnaire (IBDQ)]. Multiple regression analysis was performed by correlating MR-E score, CDAI and IBDQ. Frequencies were then compared using the χ (2) test.

RESULTS

MR-E identified inactive disease in 9% of cases, chronic disease in 57% and active disease in the remaining 34%. The most frequently involved bowel segment was the terminal ileum (52%). A statistically significant correlation was found between MR-E score and CDAI (R=0.86; p<0.001) and between MR-E score and IBDQ (R=-0.83; p<0.001). The most suggestive parameter for disease activity was layered bowel-wall enhancement, a finding predominantly present in patients with increased CDAI (≥ 150) and/or local complications (χ (2)=7.13; p<0.01).

CONCLUSIONS

MR-E is a noninvasive and diagnostic imaging modality for CD study and follow-up. The MR-E score proposed in this study proved to be useful in assessing disease severity and monitoring response to treatment.

Small bowel Crohn's disease MRI pictorial essay

The focus of this article includes 1 Revision of normal small bowel anatomy on sequences performed at our institution, with advantages and disadvantages. 2 Brief summary of the disease. 3 Appearance of acute active disease. 4 Usefulness of ancillary findings of active disease. 5 Appearance of chronic disease both active and inactive. 6 Complications of Crohn's disease. 7 Pitfalls and limitations of interpretation. 8 Clinically relevant reporting through clinician feedback.

Nontraumatic abdominal pain in pregnancy: imaging considerations for a multiorgan system problem

Nontraumatic abdominal pain in the pregnant patient can present a clinician with a variety of diagnostic possibilities. The overlap between signs and symptoms expected in normal pregnancy and these many pathologic possibilities does little to help focus the clinician's diagnostic efforts. Fear of ionizing radiation's effects on the fetus has driven efforts to refine medical imaging algorithms in such a way as to attempt to eliminate its use at all cost. In today's world, we are nearly there. In this review the differential diagnosis of nontraumatic abdominal pain in the pregnant patient will be explored. Of note is the recurring theme that much of what can be done today with regard to diagnostic imaging, both in general and with regard to this specific subset of patients, centers on the use of the non-ionizing modalities of ultrasound and magnetic resonance imaging.

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.

Radiological imaging of the small bowel

Recently introduced endoscopy-based imaging methods such as double-balloon endoscopy or wireless capsule endoscopy can visualize the complete small bowel. These approaches are quite invasive diagnostic methods. Therefore, radiological small bowel imaging is also still considered as the primary imaging approach to diagnose pathological changes of the small bowel. In this review article the most important small bowel imaging modalities such as conventional fluoroscopy, computed tomography, magnetic resonance imaging and ultrasound are discussed. Additionally the most important diseases, which can affect the small bowel, are evaluated and the optimal imaging modalities are pointed out, respectively.