How we do it: MR enterography

Preoperative Magnetic Resonance Enterography to Predict Pathological Specimen Length in Crohn's Disease

BACKGROUND

The European Crohn's and Colitis Organization guidelines have highlighted the importance of the preoperative evaluation of the affected segment length in patients with ileocolic Crohn's disease to determine the best surgical approach.

OBJECTIVE

This study aimed to evaluate the accuracy of preoperative magnetic resonance enterography in assessing the length of the affected segment in patients with ileocolic Crohn's disease.

DESIGN

This observational study was conducted with a prospectively maintained database and retrospective analysis.

SETTINGS

This study was conducted in a tertiary center.

PATIENTS

This study included consecutive patients undergoing ileocolic resection for Crohn's disease between August 2014 and June 2020. All patients underwent a preoperative magnetic resonance enterography.

MAIN OUTCOME MEASURES

The correlation between the length measured on magnetic resonance enterography and pathological examination was evaluated.

RESULTS

A total of 96 patients were included. The median time between magnetic resonance enterography and surgery was 65.5 (3-331) days. The length of the affected segment on magnetic resonance enterography was correlated with the length assessed on pathological evaluation ( R = 0.48, p < 0.001). No correlation was found between the 2 measurements when imaging was performed >6 months before surgery ( R = 0.14, p = 0.62). The presence of an abscess underestimated the length affected by Crohn's disease on imaging compared to pathology, whereas the presence of a fistula was associated with magnetic resonance enterography overestimation of the length of the affected segment.

LIMITATIONS

Limitations included single-center study and retrospective analysis.

CONCLUSION

In Crohn's disease, preoperative magnetic resonance enterography is a highly reliable tool for predicting the length of the affected segment compared to pathology examination in the absence of an abscess or fistula. See Video Abstract at http://links.lww.com/DCR/C26 .

ENTEROGRAFA POR RESONANCIA MAGNTICA PREOPERATORIA PARA PREDECIR LA LONGITUD DE MUESTRAS PATOLGICAS EN LA ENFERMEDAD DE CROHN

ANTECEDENTES:Las guías de la Organización Europea de Crohn y Colitis han resaltado la importancia de la evaluación preoperatoria de la longitud del segmento afectado para determinar el mejor abordaje quirúrgico.OBJETIVO:Evaluamos la precisión de la enterografía por resonancia magnética preoperatoria para evaluar la longitud del segmento afectado en pacientes con enfermedad de Crohn ileocólica.DISEÑO:Realizamos un estudio observacional con una base de datos mantenida prospectivamente y un análisis retrospectivo.CONFIGURACIÓN:Este estudio se realizó en un centro terciario.PACIENTES:Se incluyeron pacientes consecutivos sometidos a resección ileocólica por enfermedad de Crohn entre Agosto de 2014 y Junio de 2020. A todos los pacientes se les realizó una enterografía por resonancia magnética preoperatoria.PRINCIPALES MEDIDAS DE RESULTADO:Se evaluó la correlación entre la longitud medida en la enterografía por resonancia magnética y el examen patológico.RESULTADOS:Se incluyeron un total de 96 pacientes. El tiempo mediano entre la enterografía por resonancia magnética y la cirugía fue de 65,5 (3-331) días. La longitud del segmento afectado en la enterografía por resonancia magnética se correlacionó con la longitud evaluada en la evaluación patológica ( R = 0,48, p < 0,001). No hubo correlación entre las 2 mediciones cuando las imágenes se realizaron más de 6 meses antes de la cirugía ( R = 0,14, p = 0,62). La presencia de un absceso subestimó la longitud afectada por la enfermedad de Crohn en las imágenes en comparación con la patología, mientras que la presencia de una fístula se asoció con una sobrestimación de la longitud del segmento afectado por enterografía por resonancia magnética.LIMITACIONES:Las limitaciones incluyeron un estudio de un solo centro y un análisis retrospectivo.CONCLUSIÓNES:En la enfermedad de Crohn, la enterografía por resonancia magnética preoperatoria es una herramienta altamente confiable para predecir la longitud del segmento afectado en comparación con el examen de patología, en ausencia de absceso o fístula. Consulte el Video Resumen en http://links.lww.com/DCR/C26 . (Traducción-Dr. Yesenia Rojas-Khalil ).

Role of abbreviated non-contrast-enhanced MR-enterography in the evaluation of Crohn's disease activity and complications as an alternative for full protocol contrast-enhanced study: A systematic review and meta-analysis

Background

Crohn's disease (CD) is a chronic disorder that often starts at a young age and involves periods of remission and relapse. Prompt diagnosis of relapses through screening is crucial due to the potential morbid complications of untreated active inflammation. Magnetic resonance enterography (MRE) is a noninvasive technique to screen for active inflammation. The standard protocol involves intravenous injection of contrast agents with potential side effects. Some abbreviated non-contrast-enhanced MRE protocols are proposed as alternatives for conventional MRE to identify active inflammation. Currently, there is controversy regarding the applicability and accuracy of these protocols. This study aims to describe and compare these protocols and evaluate their accuracy in detecting active inflammation and CD complications.

Methods

Results from a systematic search of three databases in August 2022 were queried and screened by abstract and full text. Eligible studies were qualitatively and quantitatively analyzed by diagnostic test accuracy meta-analysis.

Results

59 studies entered the systematic review, and 37 were eligible for meta-analysis. Diffusion-weighted imaging (DWI) and fast T2-weighted (T2w) sequences were most frequently used in abbreviated protocols and showed non-inferior accuracy compared to the full protocol in detecting active inflammation. ADC and qualitative DWI had pooled sensitivity of 90% (CI: 82-95%) and 89% (CI:82-93%) and pooled specificity of 94% (CI: 88-97%) and 89% (CI: 79-94%), respectively for detecting active inflammation. Moreover, T2w and combined T2w+DWI sequences had pooled sensitivity of 80% (CI: 64-90%) and 76% (CI: 61-86%) and pooled specificity of 90% (CI: 80-95%) and 87% (CI: 74 - 94%), respectively. Unenhanced protocols show relatively poor diagnostic accuracy in detecting penetrating complications of CD. Magnetization transfer imaging (MTI) has demonstrated excellent accuracy in detecting fibrosis. High heterogeneity was observed in all subgroups, and accuracy was reported to be highly operator dependent in most studies.

Conclusion

An abbreviated protocol consisting of DWI and fast T2w imaging can potentially replace the full protocol MRE. Full protocol MRE will still have its role in identifying penetrating complications. MTI should be indicated in case of suspected fibrostenotic disease.

ACR Appropriateness Criteria® Crohn Disease-Child

Crohn disease is an inflammatory condition of the gastrointestinal tract with episodes of exacerbation and remission occurring in children, adolescents, and adults. Crohn disease diagnosis and treatment depend upon a combination of clinical, laboratory, endoscopic, histological, and imaging findings. Appropriate use of imaging provides critical information in the settings of diagnosis, assessment of acute symptoms, disease surveillance, and therapy monitoring. Four variants are discussed. The first variant discusses the initial imaging for suspected Crohn disease before established diagnosis. The second variant pertains to appropriateness of imaging modalities during suspected acute exacerbation. The third variant is a substantial discussion of recommendations related to disease surveillance and monitoring of Crohn disease. Finally, panel recommendations and discussion of perianal fistulizing disease imaging completes the document. The American College of Radiology Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision include an extensive analysis of current medical literature from peer reviewed journals and the application of well-established methodologies (RAND/UCLA Appropriateness Method and Grading of Recommendations Assessment, Development, and Evaluation or GRADE) to rate the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where evidence is lacking or equivocal, expert opinion may supplement the available evidence to recommend imaging or treatment.

Overview of the Large Bowel Assessment Using Magnetic Resonance Imaging: Different Techniques for Current and Emerging Clinical Applications

Radiological assessments of the small and large bowel are essential in daily clinical practice. Over plain film X-ray and ultrasound, cross-sectional techniques are considered the most comprehensive imaging modalities. In fact, computed tomography and magnetic resonance imaging take great advantage of the three-dimensional appraisal and the extensive evaluation of the abdominal cavity, allowing intestinal evaluation as well as detection of extra-intestinal findings. In this context, the chief advantage of computed tomography is the fast scan time, which is crucial for emergency cases. Nonetheless, it is undeniably impaired using ionizing radiation. As the awareness of radiation exposure is a topic of increasing importance, magnetic resonance imaging is not only becoming a mere alternative but also a primary imaging technique used in assessing intestinal diseases. Specifically, the evaluation of the large bowel through MRI can be still considered relatively uncharted territory. Although it has demonstrated superior accuracy in the assessment of some clinical entities from inflammatory bowel disease to rectal carcinoma, its role needs to be consolidated in many other conditions. Moreover, different technical methods can be applied for colonic evaluation depending on the specific disease and segment involved. This article aims to provide a thorough overview of the techniques that can be utilized in the evaluation of the large bowel and a discussion on the major findings in different colonic pathologies of primary interest.

Gentle Touch: Noninvasive Approaches to Improve Patient Comfort and Cooperation for Pediatric Imaging

Pediatric imaging presents unique challenges related to patient anxiety, cooperation, and safety. Techniques to reduce anxiety and patient motion in adults must often be augmented in pediatrics, because it is always mentioned in the field of pediatrics, children are not miniature adults. This article will review methods that can be considered to improve patient experience and cooperation in imaging studies. Such techniques can range from modifications to the scanner suite, different ways of preparing and interacting with children, collaborating with parents for improved patient care, and technical advances such as accelerated acquisition and motion correction to reduce artifact. Special considerations for specific populations including transgender patients, neonates, and pregnant women undergoing fetal imaging will be described. The unique risks of sedation in children will also be briefly reviewed.

Clinical-stage Approaches for Imaging Chronic Inflammation and Fibrosis in Crohn's Disease

The number of imaging-based indices developed for inflammatory bowel disease as research tools, objectively measuring ileocolonic and perianal activity and treatment response, has expanded in the past 2 decades. Created primarily to assess Crohn's disease (CD), there is increasing adoption of these indices into the clinical realm to guide patient care. This translation has been facilitated by validation in adult and pediatric populations, prompted by simplification of score calculations needed for practical application outside the research environment. The majority of these indices utilize magnetic resonance imaging (MRI), specifically MR enterography (MRE) and pelvic MRI, and more recently ultrasound. This review explores validated indices by modality, anatomic site and indication, including for documentation of the presence and extent of CD, disease progression, complications, and treatment response, highlighting those in clinical use or with the potential to be. As well, it details index imaging features used to quantify chronic inflammatory activity, severity, and to lesser extent fibrosis, in addition to their reference standards and any modifications. Validation in the pediatric population of indices primarily developed in adult cohorts such as the Magnetic Resonance Index of Activity (MaRIA), the Simplified Magnetic Resonance Index of Activity (MARIAs), and the MRE global score (MEGS), together with newly developed pediatric-specific indices, are discussed. Indices that may be predictive of disease course and investigational techniques with the potential to provide future imaging biomarkers, such as multiparametric MRI, are also briefly considered.

Fast Magnetic Resonance Enterography Protocol for the Evaluation of Patients with Crohn's Disease: A Pilot Study

Objective

Magnetic resonance enterography has achieved an increasingly importance in the evaluation of patients with Crohn's disease, although it is limited by high costs and prolonged scanning times. The aim of our work was to design a "fast" abbreviated MRE protocol and to compare it with the standard one.

Materials and Methods

A single-center retrospective study was performed on 73 patients with Crohn's disease who underwent MRE with standard protocol over a 7-month period. The images of the standard protocol were separated from those included in the proposed abbreviated one and independently evaluated by two radiologists with different years of experience in MRE imaging. Statistical analysis was performed with the Cohen kappa (κ) value, used to assess the agreement in case of categorical variables, the Lin's concordance correlation coefficient and Bland-Altman plot, in assessing the degree of agreement between numerical measurements, while the non- parametric Mann-Whitney U-test was used in comparing the evaluation times of the two protocols.

Results

The intraobserver evaluation showed a perfect agreement between the two protocols for presence, number and extension of lesions, abdominal complications, and excellent/perfect in identification of active inflammation.The interobserver reproducibility was excellent for overall presence and number of lesions, for the presence and number of lesions in any abdominal quadrant, inflammation, intestinal and extraintestinal complications, and lesions extension.

Conclusion

The proposed protocol achieves comparable performance with standard MRE. Furthermore, it would carry potential benefits in terms of patient's comfort, time, and health-care costs savings.

Autoinflammatory diseases in childhood, part 2: polygenic syndromes

Autoinflammatory diseases are a family of disorders characterized by aberrant stimulation of inflammatory pathways without involvement of antigen-directed autoimmunity. They can be further divided in monogenic and polygenic types. Those without an identified genetic mutation are known as polygenic and include systemic-onset juvenile idiopathic arthritis, idiopathic recurrent acute pericarditis, Behçet syndrome, chronic recurrent multifocal osteomyelitis and inflammatory bowel disease among others. Autoinflammatory diseases are characterized by recurrent flares or persistent systemic inflammation and fever, as well as lymphadenopathy and cutaneous, abdominal, thoracic and articular symptoms. Although these syndromes can mimic infections clinically, the inflammatory lesions in autoinflammatory disorders are aseptic. However, because of their infrequency, varied and nonspecific presentation, and the new genetic identification, diagnosis is usually delayed. In this article, which is Part 2 of a two-part series, the authors review the main polygenic autoinflammatory diseases that can be seen in childhood, with special emphasis wherever applicable on imaging features that may help establish the correct diagnosis. However, the major role of imaging is to delineate organ involvement and disease extent.

Magnetic resonance enterography evaluation of Crohn disease activity and mucosal healing in young patients

MR enterography (MRE) has become the primary imaging modality for assessing Crohn disease in young patients because of its lack of ionizing radiation, superior soft-tissue contrast, and cross-sectional capability to evaluate disease activity as well as extraluminal and extra-intestinal complications. MRE has been extensively validated against both histological and endoscopic references as a noninvasive imaging biomarker of Crohn disease activity. More recent studies have also validated MRE as a noninvasive biomarker of mucosal healing, an important endpoint of Crohn disease therapy. In this review, we summarize the current evidence supporting the use of MRE features as imaging biomarkers of Crohn disease activity and treatment response.

Paediatric magnetic resonance enterography in inflammatory bowel disease

Paediatric magnetic resonance enterography (MRE) has been increasingly employed in the evaluation of inflammatory bowel disease (IBD) in the past decade. This is in parallel with a global rise in paediatric-onset IBD, greater recognition of the hazards of ionizing radiation, especially in children, and improved treatment options. MRE is now the reference standard for assessing the small bowel in suspected or proven paediatric IBD, and is central to the diagnosis of Crohn's disease (CD), helping distinguish it from ulcerative colitis. This review will discuss the standard and advanced techniques applied in paediatric MRE to define the presence, extent and severity of intestinal IBD, and increasingly colonic and perianal disease. Its role in demonstrating enteric and extra-enteric disease and characterizing this as active inflammation and/or damage will be explored, including the utility of cinematic, diffusion weighted and magnetization transfer imaging. While MRE is increasingly used to guide medical versus surgical management, considerable overlap exists between conventional MRE imaging features for inflammation and damage, as reflected pathologically, which is driving ongoing research. Paediatric MRE-based scoring systems for CD are currently under development that will further consolidate the role of MRE in paediatric IBD, reinforced by implementation of standardized analysis, interpretation and reporting. As an imaging biomarker, MRE performs well when referenced against endoscopy and clinical biomarkers for evidence of mucosal healing, the current treatment goal. MRE is anticipated to have even greater impact as an imaging biomarker through demonstration of transmural disease and healing, not amenable to endoscopic assessment.

Comparison of Conventional Ultrasound and Contrast Enhanced Magnetic Resonance (MR) Enterography in Evaluation Patients with Crohn's Disease

Introduction

The small intestine is a challenging organ for clinical and radiological evaluation, and by introducing imaging radiological techniques, not significantly disturbing the comfort and safety of patients, it attempts to obtain adequate diagnosis and valuable information.

Aim

The research was conducted with the aim of checking the comparability and potential of diagnostic modality of ultrasound and dynamic contrast enhanced MR Enterography (DCE-MR) in patients with Crohn's disease.

Methods

55 patients were examined prospectively, and ultrasound examination of the abdomen was performed for all patients before the MR enterography. They were subsequently endoscopically examined or treated surgically, which was taken as a reference. Four parameters characterizing the disease itself were analyzed: bowel wall thickening, presence of abscess, fistula and lymphadenopathy.

Results

Comparing the accuracy of the results of ultrasound findings and findings of MR enterography, it was found that there is a significant difference in the results obtained. The study found that the sensitivity for MR enterography for bowel wall thickening was 97.8%, and the specificity was 70%, while the sensitivity for ultrasound for the bowel wall thickening was 51% and the specificity was 100%. In the diagnosis of abscess, there was no significant difference between the results obtained by ultrasound and magnetic resonance imaging (MRI) findings, while in fistula and lymphadenopathy there was a significant difference.

Conclusion

Conventional ultrasound is a good orientation method in the initial evaluation of patients with Crohn's disease, while contrast enhanced MR enterography provides an excellent assessment for disease activity as well as the complications that accompany it.

The role of imaging in the preoperative assessment of children with inflammatory colitis

BACKGROUND

Accurate diagnosis of Crohn's disease or ulcerative colitis is essential for surgical planning. This study compared the accuracy, safety, and utility of small bowel follow-through (SBFT) and magnetic resonance enterography (MRE) for detecting small bowel (SB) involvement preoperatively.

METHODS

A retrospective review of children who underwent colectomy for inflammatory bowel disease (2000-2014) was performed. Preoperative SBFT and MRE were independently reviewed by two radiologists blinded to clinical data. Gold standard for diagnosis was surgical pathology.

RESULTS

68 patients (36 female) were included. 45 patients had SBFT prior to colectomy, 17 patients had MRE, and 6 both. Interrater reliability for radiologic interpretation was 90% (SBFT) and 91% (MRE). Mean study durations were 190min (SBFT) and 59min (MRE). Median effective dose for SBFT was 1.5mSv, while MRE involved no ionizing radiation. Specificities for diagnosing SB involvement were 87.5% (SBFT) and 94% (MRE). 54 patients underwent subtotal colectomy and ileostomy, 12 restorative proctocolectomy, and 2 colectomy with ileorectal anastomosis. Preoperative imaging correlated with surgical pathology in 83% (SBFT) and 90% (MRE).

CONCLUSION

MRE is at least as effective as SBFT for assessing SB disease in children with colitis prior to colectomy. MRE requires less time and does not expose children to ionizing radiation. Retrospective Case Series, Level 4 Evidence.