Evaluation of an MRI-based score of disease activity in perianal fistulizing Crohn's disease

The role of MRI in perianal fistulizing disease: diagnostic imaging and classification systems to monitor disease activity

Perianal fistulizing disease, commonly associated with Crohn's disease, poses significant diagnostic and therapeutic challenges due to its complex anatomy and high recurrence rates. Radiological imaging plays a pivotal role in the accurate diagnosis, classification, and management of this condition. This article reviews the current radiological modalities employed in the evaluation of perianal fistulizing disease, including magnetic resonance imaging (MRI), endoanal ultrasound, and computed tomography (CT). MRI, recognized as the gold standard, offers superior soft tissue contrast and multiplanar capabilities, facilitating detailed assessment of fistula tracts and associated abscesses. CT, although less detailed than MRI, remains valuable in acute settings for detecting abscesses and guiding drainage procedures. This article discusses the advantages and limitations of each modality, highlights the importance of standardized imaging protocols, and underscores the need for interdisciplinary collaboration in the management of perianal fistulizing disease. Future directions include advancements in imaging techniques and the integration of artificial intelligence to enhance diagnostic accuracy and treatment outcomes.

Scoring Indices for Perianal Fistulising Crohn's Disease: A Systematic Review

BACKGROUND AND AIMS

In this systematic review we summarise existing scoring indices for assessing disease activity and quality of life in perianal fistulising Crohn's disease [PFCD], and highlight gaps in the literature.

METHODS

MEDLINE, EMBASE, and CENTRAL were searched from August 24, 2022, to identify studies evaluating clinical, radiological, or patient-reported outcome measures [PROMS] in PFCD. The primary objective was to identify all available scoring indices and describe the operating properties of these indices.

RESULTS

A total of 53 studies reported on the use of one clinical index [Perianal Disease Activity Index: PDAI], three PROMs, and 10 radiological indices; 25 studies evaluated the operating properties of these indices. The PDAI demonstrated content validity, construct validity, and responsiveness but criterion validity or reliability were not assessed. The Van Assche Index [VAI], modified VAI, and the Magnetic Resonance Index for Assessing Fistulas in Patients with CD [MAGNIFI-CD] were the most studied radiological indices. These indices demonstrated responsiveness and reliability. The VAI and MAGNIFI-CD demonstrated construct validity; criterion and content validity and feasibility have not been assessed. Among the three PROMs, the Crohn's Anal Fistula Quality of Life index demonstrated content and construct validity, inter-observer reliability, and responsiveness; criterion validity, intra-observer reliability, and feasibility have not been assessed for this index.

CONCLUSIONS

There are no fully valid, reliable, and responsive clinical disease or radiological indices for PFCD. Although the radiological indices demonstrated responsiveness and reliability, well-defined cut-offs for response and remission are lacking. Future research should focus on establishing standardised definitions and thresholds for outcomes.

Management of Perianal Fistulizing Crohn's Disease

Perianal fistulizing Crohn's disease (CD) represents a severe phenotype of CD that is associated with significant morbidity and reduction in quality of life. Perianal fistulizing CD is caused by a complex interplay of genetic predisposition, immune dysregulation, gut dysbiosis, and various unknown physiological and mechanical factors. A multidisciplinary approach is hence required for optimal management . A detailed anatomical description and classification of perianal fistula, including comprehensive clinical, endoscopic, and radiological diagnostic workup, is an important prerequisite to treatment. For simple perianal fistulas, use of antibiotics and immunomodulators, with or without fistulotomy, are appropriate measures. The medical management of complex perianal fistula, on the other hand, requires adequate control of infection before initiation of therapy with immunomodulators. In active complex perianal fistula, anti-tumor necrosis factors remain the most accepted therapy, with concomitant use of antibiotics or immunomodulators enhancing the efficacy. For patients refractory to anti-tumor necrosis factors, treatment with anti-integrins, anti-interleukins, and small molecules is being evaluated. Mesenchymal stem cells, hyperbaric oxygen therapy, and exclusive enteral nutrition have also been investigated as adjunct therapies. Despite the expansion of the medical armamentarium, a large proportion of the patients require surgical interventions. In this review, we provide an up-to-date overview of the pathophysiology, clinical presentation, diagnosis, and medical management of perianal fistulizing CD. A brief overview of the surgical management of perianal fistulizing CD is also provided.

The relationship between perianal fistula activity and abdominal adipose tissue in Crohn’s disease: an observational study

Objective

The aim of this study was to analyze the relationship between abdominal adipose tissue and perianal fistula activity in patients with Crohn's disease (CD) using cross-sectional imaging.

Methods

Patients with perianal fistulizing CD who underwent pelvic magnetic resonance imaging (MRI) and abdominal computed tomography (CT) were retrospectively enrolled. We scored the fistulas in each patient's MRI images based on Van Assche's classification. The area and density of subcutaneous adipose tissue (SAT) and visceral adipose tissue (VAT) (at the third, fourth, and fifth lumbar (L3, L4, and L5) levels were measured by averaging five slices of measurements at each vertebral level in CT images, and areas were further standardized by the lumbar height2 (heightL1-5). The VAT/SAT ratio (VSR) and VAT/Total adipose tissue (VA/TA) index were calculated. Based on MRI scores, patients were divided into two groups with low and high activity, and their clinical, MRI features, and CT parameters were compared. We evaluated patients with follow-up MRI and compared the differences in clinical and radiological indicators among patients with different outcomes.

Results

Overall, 136 patients were included, 77 in the low-activity group and 59 in the high-activity group. Patients in the high activity group had lower subcutaneous adipose index (all levels, p < 0.05) and visceral adipose index (L3 level, p < 0.01), but higher SAT and VAT density (all levels, p < 0.01), VSR (L5 level, p = 0.07) and VA/TA index (L5 level, p < 0.05).

Conclusion

There were differences in adipose tissue composition among CD patients with different active perianal fistulas.

Tools for the Diagnosis and Management of Crohn's Disease

Numerous tools have emerged over recent decades to aid in the increasingly complex management of patients with Crohn's disease (CD) beyond endoscopy, including video capsule endoscopy, magnetic resonance enterography, computed tomography enterography, a variety of biomarkers, and even wearable biosensors and smartphone applications. These tools have allowed for a more sophisticated and less invasive complementary approach to the evaluation of disease activity and treatment response in patients with CD. This article details the characteristics, practical application, and limitations of these various modalities and discusses how updated guidelines are now incorporating many of them into a treat-to-target strategy.

ECCO-ESGAR Topical Review on Optimizing Reporting for Cross-Sectional Imaging in Inflammatory Bowel Disease

BACKGROUND AND AIMS

The diagnosis and follow up of patients with inflammatory bowel disease [IBD] requires cross-sectional imaging modalities, such as intestinal ultrasound [IUS], magnetic resonance imaging [MRI] and computed tomography [CT]. The quality and homogeneity of medical reporting are crucial to ensure effective communication between specialists and to improve patient care. The current topical review addresses optimized reporting requirements for cross-sectional imaging in IBD.

METHODS

An expert consensus panel consisting of gastroenterologists, radiologists and surgeons convened by the ECCO in collaboration with ESGAR performed a systematic literature review covering the reporting aspects of MRI, CT, IUS, endoanal ultrasonography and transperineal ultrasonography in IBD. Practice position statements were developed utilizing a Delphi methodology incorporating two consecutive rounds. Current practice positions were set when ≥80% of the participants agreed on a recommendation.

RESULTS

Twenty-five practice positions were developed, establishing standard terminology for optimal reporting in cross-sectional imaging. Assessment of inflammation, complications and imaging of perianal CD are outlined. The minimum requirements of a standardized report, including a list of essential reporting items, have been defined.

CONCLUSIONS

This topical review offers practice recommendations to optimize and homogenize reporting in cross-sectional imaging in IBD.

Development and Validation of a Pediatric MRI-Based Perianal Crohn Disease (PEMPAC) Index-A Report from the ImageKids Study

BACKGROUND

As part of the prospective multicenter ImageKids study, we aimed to develop and validate the pediatric MRI-based perianal Crohn disease (PEMPAC) index.

METHODS

Children with Crohn disease with any clinical perianal findings underwent pelvic magnetic resonance imaging at 21 sites globally. The site radiologist and 2 central radiologists provided a radiologist global assessment (RGA) on a 100 mm visual analog scale and scored the items selected by a Delphi group of 35 international radiologists and a review of the literature. Two weighted multivariable statistical models were constructed against the RGA.

RESULTS

Eighty children underwent 95 pelvic magnetic resonance imaging scans; 64 were used for derivation and 31 for validation. The following items were included: fistula number, location, length and T2 hyperintensity; abscesses; rectal wall involvement; and fistula branching. The last 2 items had negative beta scores and thus were excluded in a contending basic model. In the validation cohort, the full and the basic models had the same strong correlation with the RGA (r = 0.75; P < 0.01) and with the adult Van Assche index (VAI; r = 0.93 and 0.92; P < 0.001). The correlation of the VAI with the RGA was similar (r = 0.77; P < 0.01). The 2 models and the VAI had a similar ability to differentiate remission from active disease (area under the receiver operating characteristic curve, 0.91-0.94). The PEMPAC index had good responsiveness to change (area under the receiver operating characteristic curve, 0.89; 95% confidence interval, 0.69-1.00).

CONCLUSIONS

Using a blended judgmental and mathematical approach, we developed and validated an index for quantifying the severity of perianal disease in children with CD. The adult VAI may also be used with confidence in children.

Patient-Reported Outcomes Measures in Perianal Fistulizing Crohn's Disease

Perianal fistulizing Crohn's disease (PFCD) is a disabling complication of Crohn's disease (CD) that can significantly impact on patients' quality of life (QoL) and often requires multidisciplinary care. Clinical trials assessing the efficacy of medical and surgical interventions for fistulas usually evaluate outcomes such as closure of fistula tracts or radiologic healing. However, these traditional outcome assessments fail in capturing the impact of the disease from patients' perspectives. In this context, regulatory authorities have increasingly encouraged the inclusion of validated patient-reported outcomes (PRO) that assess disease activity and reveal how a patient functions and feels. This recent trend towards patient-centered care aims to ensure that improvements in efficacy outcomes are accompanied by meaningful benefits to patients. The aim of this review is to discuss currently available PRO measures (PROMS) for the assessment of PFCD to provide to physicians appropriate tools aiming to optimize patient care and disseminate the use of these instruments in clinical practice.

Quantitative Magnetic Resonance Imaging in Perianal Crohn's Disease at 1.5 and 3.0 T: A Feasibility Study

Perianal Crohn's Disease (pCD) is a common manifestation of Crohn's Disease. Absence of reliable disease measures makes disease monitoring unreliable. Qualitative MRI has been increasingly used for diagnosing and monitoring pCD and has shown potential for assessing response to treatment. Quantitative MRI sequences, such as diffusion-weighted imaging (DWI), dynamic contrast enhancement (DCE) and magnetisation transfer (MT), along with T2 relaxometry, offer opportunities to improve diagnostic capability. Quantitative MRI sequences (DWI, DCE, MT and T2) were used in a cohort of 25 pCD patients before and 12 weeks after biological therapy at two different field strengths (1.5 and 3 T). Disease activity was measured with the Perianal Crohn's Disease Activity index (PDAI) and serum C-reactive protein (CRP). Diseased tissue areas on MRI were defined by a radiologist. A baseline model to predict outcome at 12 weeks was developed. No differences were seen in the quantitative MR measured in the diseased tissue regions from baseline to 12 weeks; however, PDAI and CRP decreased. Baseline PDAI, CRP, T2 relaxometry and surgical history were found to have a moderate ability to predict response after 12 weeks of biological treatment. Validation in larger cohorts with MRI and clinical measures are needed in order to further develop the model.

Development and initial psychometric validation of a patient-reported outcome measure for Crohn's perianal fistula: the Crohn's Anal Fistula Quality of Life (CAF-QoL) scale

INTRODUCTION

Crohn's perianal fistulas are challenging for patients and clinicians. Many do not respond to available treatments and despite recommendations by a global consensus, there are currently no specific patient-derived quality of life tools to measure response to treatment. We present a new validated patient-reported outcome measure (PROM) for this complicated disease phenotype.

METHODS

A draft questionnaire was generated using unstructured qualitative patient interviews on the experience of living with Crohn's perianal fistula, a nationwide multidisciplinary consensus exercise, a systematic review of outcomes assessing medical/surgical/combined treatment and a patient and public involvement day. Psychometric properties were assessed including construct validity (by comparison with the Hospital Anxiety and Depression Scale (HADS) and the UK Inflammatory Bowel Disease Questionnaire (UK-IBDQ)), and reliability and responsiveness was assessed by test-retest analysis.

RESULTS

Data from 211 patients contributed to development of a final 28-item questionnaire. The Crohn's Anal Fistula Quality of Life (CAF-QoL) demonstrated good internal consistency (Cronbach's alpha 0.88), excellent stability (intraclass correlation 0.98) and good responsiveness and construct validity, with positive correlation with the UK-IBDQ and HADS.

CONCLUSION

The CAF-QoL scale is ready for use as a PROM in research and clinical practice. It complements objective clinical evaluation of fistula by capturing impact on the patient.

Endpoints for Perianal Crohn's Disease Trials: Past, Present and Future

BACKGROUND AND AIMS

Since the 1980s, many studies have evaluated the efficacy of therapies to improve the outcomes of patients with perianal Crohn's disease. We performed a systematic review to describe the evolution of endpoints in perianal fistulizing Crohn's disease. Efficacy outcomes, definitions and measurement tools were assessed.

METHODS

Electronic databases were searched up to November 1, 2020. All published randomized placebo-controlled trials enrolling patients with perianal fistula and Crohn's disease were eligible for inclusion. Ongoing randomized clinical trials were also described.

RESULTS

Nineteen randomized controlled trials were included. Clinical efficacy endpoints were reported in all trials. Clinical response was the most frequent primary endpoint [6/19 studies, 31.6%], followed by clinical remission in four studies [21%]. Clinical response was defined as closure of at least 50% of fistulas, while remission was defined as closure of all fistulas. A combined clinical and radiological primary endpoint was used to assess fistula healing in four studies [21%]. The Perianal Disease Activity Index was a primary endpoint in only one study [5.5%]. In addition, eight ongoing controlled trials were identified. Combined clinical and radiological remission was the most frequent primary endpoint in these studies [4/8, 50%].

CONCLUSION

In this systematic review, significant changes in outcomes used in randomized clinical trials of perianal Crohn's disease were observed. Radiological endpoints are increasingly used in perianal fistulizing Crohn's disease trials.

Approach to medical therapy in perianal Crohn's disease

Perianal Crohn's disease remains a challenging condition to treat and can have a substantial negative impact on quality of life. It often requires combined surgical and medical interventions. Anti-tumor necrosis factor (anti-TNF) therapy, including infliximab and adalimumab, remain preferred medical therapies for perianal Crohn's disease. Infliximab has been shown to be efficacious in improving fistula closure rates in randomized controlled trials. Clinicians can be faced with a number of questions relating to the optimal use of anti-TNF therapy in perianal Crohn's disease. Specific issues include evaluation for the presence of perianal sepsis, the treatment target of therapy, the ideal time to commence treatment, whether additional medical therapy should be used in conjunction with anti-TNF therapy, and the duration of treatment. This article will discuss key studies which can assist clinicians in addressing these matters when they are considering or have already commenced anti-TNF therapy for the treatment of perianal Crohn's disease. It will also discuss current evidence regarding the use of vedolizumab and ustekinumab in patients who are failing to achieve a response to anti-TNF therapy for perianal Crohn's disease. Lastly, new therapies such as local injection of mesenchymal stem cell therapy will be discussed.

Long-term outcomes of perianal fistulizing Crohn's disease in the biologic era

Background and Aim

While the advent of biologic therapy has led to improved outcomes in perianal fistulizing Crohn's disease (pfCD), loss of response is common. Previous studies suggest that patients who achieve radiological healing (with healing of underlying tracts on magnetic resonance imaging [MRI]) have a longer duration of response. The aim of this study was to characterize MRI outcomes of pfCD at a specialist inflammatory bowel disease (IBD) unit and compare the long-term clinical outcomes between patients achieving MRI and clinical healing.

Methods

A retrospective analysis of perianal fistulizing Crohn's patients treated at one specialist IBD unit was performed. Records were reviewed for patient demographics, disease history, clinical assessments, investigation results, and disease flares. Clinical remission was defined as closure of all baseline fistula openings. Radiological healing was defined as the absence of any T2-hyperintense sinuses, tracts, or collections. The primary end-point was rate of MRI healing. The secondary outcome was defined as flare-free period (time between clinical or radiological healing and patients' first signs/symptoms requiring therapy escalation).

Results

A total of 93 patients were included, with a median follow-up of 4.8 years (interquartile range, 2.4-6 years). Of 44 patients, 22 (50%) achieved clinical remission, while 15 of 93 (16%) achieved radiological healing. Of 22 patients, 10 (45%) with clinical remission had a subsequent disease flare (median time of 7 months) compared with 3 of 15 (20%) patients with MRI healing (median time of 3.6 years). Radiological healing was associated with a significantly longer flare-free period (P = 0.01).

Conclusion

Radiological healing occurs less commonly but represents a deeper form of healing, associated with improved long-term clinical outcomes.

Modified Van Assche magnetic resonance imaging-based score for assessing the clinical status of anal fistulas

The modified Van Assche magnetic resonance imaging (MRI)-based score is a feasible system to assess the clinical status of anal fistulas in Crohn disease. In this study, we evaluated this score's association with clinical status in patients with anal fistulas (AFs).We included all patients with AF who underwent contrast-enhanced pelvic MRI and surgery between January 2011 and December 2016. The score was evaluated retrospectively preoperatively and 1, 3, and 6 months postoperatively. Univariate and multivariate analyses of the risk factors for AF recurrence were also performed.We retrospectively analyzed data for 104 patients. Twelve (11.5%) patients developed AF recurrence. We classified patients' preoperative clinical status into three grades: 52 (50.0%) grade A, 31 (29.8%) grade B, and 21 (20.2%) grade C. The preoperative MRI-based score was significantly correlated with patients' preoperative clinical status grade (Pearson correlation: 0.547; P < .001). The 3 preoperative clinical status grades showed significant (F = 23.303, P < .001) tendencies for associations with lower respective MRI-based scores. The incidence of AF recurrence decreased with the MRI-based score to 1-month postoperatively, then gradually increased (F = 60.863, P = .000). Long duration of disease, prior interventions, and high MRI-based score were independent risk factors for AF recurrence.The MRI-based score objectively assessed the clinical status and disease activity of patients with AFs, with a high score being associated with severe clinical status and long recovery time.

ESGAR consensus statement on the imaging of fistula-in-ano and other causes of anal sepsis

Objectives

To develop imaging guidelines for patients with fistula-in-ano and other causes of anal sepsis.

Methods

An expert group of 13 members of the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) used a modified Delphi process to vote on a series of consensus statements relating to the imaging of patients with potential anal sepsis. Participants first completed a questionnaire to gather practice information and to help frame the statements posed.

Results

In the first round of voting, the expert group scored 51 statements of which 45 (88%) achieved immediate consensus. The remaining 6 statements were redrafted following input from the expert group and consensus achieved for all during a second round of voting, including an additional statement drafted. No statement was rejected due to a lack of consensus. After redrafting to improve clarity, 53 individual statements were presented.

Conclusion

These expert consensus statements can be used to guide appropriate indication, acquisition, interpretation and reporting of medical imaging for patients with potential fistula-in-ano and other causes of anal sepsis.

Key Points

• Medical imaging, notably magnetic resonance imaging, is used widely for the diagnosis and monitoring of fistula-in-ano and other causes of anal and perianal sepsis.

• While the indexed medical literature is clear that diagnostic accuracy is potentially excellent, this depends on competent image acquisition and interpretation.

• In order to facilitate this, the European Society of Gastrointestinal and Abdominal Radiology (ESGAR) has produced expert consensus guidelines regarding the imaging of fistula-in-ano and related conditions.

Electronic supplementary material

The online version of this article (10.1007/s00330-020-06826-5) contains supplementary material, which is available to authorized users.

Predictors of long-term outcomes of radiologically defined perianal fistulizing Crohn's disease treated with antitumor necrosis factor-alpha agents based on Parks' classification

BACKGROUND AND AIMS

Perianal fistulizing Crohn's disease (PFCD) leads to significant disability. Data assessing healing of complex PFCD based on pelvic MRI using Parks' classification remains sparse. We aimed to assess the frequency of closure of fistula tract on MRI in patients treated with antitumor necrosis factor alpha antagonists and identify predictors of poor response.

MATERIALS AND METHODS

We retrospectively identified patients registered in the Saudi Inflammatory Bowel Disease Information System registry, who were diagnosed as PFCD based on MRI and treated with infliximab or adalimumab. Fistulae were classified based on Parks' classification and response to treatment was determined as full, partial, or no response, after at least 12 months of treatment.

RESULTS

Out of 960 patients, 61 had complex PFCD that required treatment with an anti-TNF agent. The median age was 27 years (range: 14-69 years) and the median duration of disease was 6.2 ± 5.8 years. A full response to treatment was achieved in 27 (44.4%), whereas 10 patients (16.3%) had partial response and 24 (39.3%) had no response. On univariable analysis, a statistically significant association was observed between poor fistula response and low BMI, rectal involvement, fistulae classification, and the presence of an abscess. According to multivariable regression, only low BMI predicted poor fistulae outcome (odds ratio = 1.37, 95% confidence interval: 0.69-0.98).

CONCLUSION

Less than half of this cohort of patients with PFCD achieved complete radiological fistula healing with anti-TNF therapy. Low BMI appears to be the only predictor of poor outcome.

Radiological outcomes in perianal fistulizing Crohn's disease: A systematic review and meta-analysis

Perianal fistulas are a common and debilitating manifestation of Crohn's disease. Since the advent of biological agents, patient outcomes appear to have improved. While rates of clinical response and remission are well characterized in literature, magnetic resonance imaging (MRI) outcomes remain less so. This is despite previous studies demonstrating the persistence of fistula tracts on MRI, in spite of clinical healing, suggesting radiological markers of improvement may be more accurate. The aims of this study were to systematically review the literature for all studies reporting on MRI outcomes following biological therapy and to compare rates of radiological healing to clinical remission. A search was performed according to the Preferred Reporting Items For Systematic Reviews and Meta‐Analysis (PRISMA) guidelines. Nine articles were included, with a total sample size of 259 patients. Of these 259 patients, 47% achieved clinical remission following induction therapy and 42% following a median of 52 weeks' maintenance therapy. Out of the 259 patients, 7% achieved radiological healing in the short term and 25% in the long term. The odds ratio of MRI versus clinical healing was 0.10 (95% confidence interval [CI], 0.02–0.39) and 0.43 (95% CI, 0.26–0.71), respectively, at those corresponding time points. MRI healing of perianal fistulizing Crohn's, while arguably a more accurate assessment of treatment response, is significantly less common than clinical remission. Heterogeneity exists in the definition of radiological and clinical response, leading to variation in reported rates. Further studies, directly comparing the long‐term outcomes of patients achieving clinical remission and MRI healing are required, to better inform the role of MRI follow up in clinical practice.

Evaluation of the modified Van Assche index for assessing response to anti-TNF therapy with MRI in perianal fistulizing Crohn's disease

BACKGROUND

Structured evaluation of magnetic resonance imaging (MRI) is important to guide clinical decisions of perianal fistulas in Crohn's disease (CD) patients.

PURPOSE

To evaluate the recently developed modified Van Assche index to assess clinical responses to anti-tumor necrosis factor (TNF) therapy in patients with perianal fistulizing CD.

METHODS

A search of medical records identified patients with fistulizing perianal CD who underwent baseline and follow-up MRI while receiving anti-TNF treatment. Patients were divided into clinical responders and non-responders based on physician's assessment. MRI-scans were scored using the original and modified Van Assche index and scores between baseline and follow-up were compared within clinical responders and non-responders.

RESULTS

Thirty cases were included (48% female, median age 27 years). Clinical responders (n = 16) had a median modified Van Assche score of 9.6 (IQR 5.8-12.7) at baseline and 5.8 (IQR 3.5-8.5) at follow-up (p = 0.008). In non-responders (n = 14), corresponding scores were 7.7 (IQR 5.8-13.5) and 8.2 (IQR 5.8-11.5) (p = 0.624). In clinical responders, 6/16 showed no drop in modified Van Assche score at follow-up. Scores obtained with the original Van Assche index dropped between baseline and follow-up in clinical responders (13.0 vs. 9.6, p = 0.011), whereas no decrease was observed in non-responders (11.5 vs. 11.5, p = 0.324).

CONCLUSIONS

While the modified Van Assche index overall decreases significantly in patients with perianal fistulas responding to anti-TNF treatment, one third of responders had unaltered scores at follow-up. Also, outcomes were comparable to the original Van Assche index. Further optimization of the modified Van Assche index is needed before application in larger studies.

Development and Validation of a Magnetic Resonance Index for Assessing Fistulas in Patients With Crohn's Disease

BACKGROUND & AIMS

There is no validated magnetic resonance imaging (MRI) index for assessment of perianal fistulas in patients with Crohn's disease (CD). We developed and internally validated a new instrument.

METHODS

We used paired baseline and week-24 MRI scans from 160 participants in a randomized placebo-controlled trial of stem cell therapy for patients with perianal fistulizing CD. Four radiologists scored disease activity using index items identified during previous studies and exploratory items. Reliability was assessed using intraclass correlation coefficients. We developed an index using backward elimination linear regression analysis, in which potential independent variables were items having intraclass correlation coefficients of at least 0.4 and the dependent variable was perianal fistulizing disease activity, measured on a 100-mm visual analogue scale. The final model was internally validated using the .632 bootstrap method to correct model optimism and quantify calibration accuracy. We evaluated responsiveness of the index by assessing longitudinal validity and estimating standardized effect sizes.

RESULTS

We developed the magnetic resonance novel index for fistula imaging in CD (MAGNIFI-CD) using 6 items. The optimism-corrected R² of the model was 0.71, which was comparable to R² for the original sample (0.74). The calibration slope for the model was 0.98. Compared with the original and modified versions of the Van Assche Index, the MAGNIFI-CD had improved operating characteristics. Estimates of intraclass correlation coefficients for MAGNIFI-CD, the modified Van Assche Index, and Van Assche Index were 0.85 (95% confidence interval [CI], 0.77-0.90), 0.81 (95% CI, 0.74-0.86), and 0.81 (95% CI, 0.71-0.86) for intra-rater reliability, and 0.74 (95% CI, 0.63-0.80), 0.67 (95% CI, 0.55-0.75) and 0.68 (95% CI, 0.56-0.77) for inter-rater reliability. Corresponding standardized effect size estimates were 1.02 (95% CI, 0.65-1.39), 0.84 (95% CI, 0.48-1.21), and 0.68 (95% CI, 0.33-1.03).

CONCLUSIONS

We developed an index called the MAGNIFI-CD, which is based on 6 items. It assesses MRI data and determines perianal fistulizing CD activity with improved operating characteristics compared to previous indices. This index may be used as an outcome measure in clinical trials comparing treatment effects in patients with perianal fistulizing CD. Although the performance of the MAGNIFI-CD indicates its stability and reasonable external validity, external validation is needed.

The treatment of anal fistula: second ACPGBI Position Statement - 2018

It is over 10 years since the first ACPGBI Position Statement on the management of anal fistula was published in 2007. This second edition is the result of scrutiny of the literature published during this time; it updates the original Position Statement and reviews the published evidence surrounding treatments for anal fistula that have been developed since the original publication.

Role of magnetic resonance imaging in the management of perianal Crohn's disease

Perianal fistulas are a major problem in many patients with Crohn's disease. These are usually complex fistulas that adversely affect patients' quality of life, and their clinical management is difficult. Medical treatment sometimes achieves cessation of discharge and closure of the external opening; however, it is difficult to assess the status of the rest of the fistula tract. Magnetic resonance imaging is the method of choice with which to evaluate the condition of perianal fistulas and allows for assessment of the status of inaccessible areas. Magnetic resonance imaging also allows the clinician to evaluate other perianal manifestations of Crohn's disease that differ from the fistulas. This imaging technique is therefore a fundamental means of patient monitoring. When used in conjunction with assessment of the patient's morphological findings, it provides information that allows for both quantification of disease severity and evaluation of the response to treatment. New types of magnetic resonance sequences are emerging, such as diffusion, perfusion, and magnetisation transfer. These sequences may serve as biomarkers because they provide information reflecting the changes taking place at the molecular level. This will help to shape a new scenario in the early assessment of the response to treatments such as anti-tumour necrosis factor drugs.

TEACHING POINTS

• MRI is the method of choice with which to evaluate perianal fistulas. • In perianal Crohn's disease, MRI is a fundamental means of patient monitoring. • The usefulness of the Van Assche score for patient monitoring remains unclear. • New MRI sequences' diffusion, perfusion, and magnetisation transfer may serve as biomarkers.

Diagnostic performance of intravoxel incoherent motion diffusion-weighted imaging and dynamic contrast-enhanced MRI for assessment of anal fistula activity

Objective

To evaluate intravoxel incoherent motion (IVIM) diffusion-weighted imaging (DWI) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) sequences for quantitative characterization of anal fistula activity.

Methods

This retrospective study was approved by the institutional review board. One hundred and two patients underwent MRI for clinical suspicion of anal fistula. Forty-three patients with demonstrable anal fistulas met the inclusion criteria. Quantitative analysis included measurement of DCE and IVIM parameters. The reference standard was clinical activity based on medical records. Statistical analyses included Bayesian analysis with Markov Chain Monte Carlo, multivariable logistic regression, and receiver operating characteristic analyses.

Results

Brevity of enhancement, defined as the time difference between the wash-in and wash-out, was longer in active than inactive fistulas (p = 0.02). Regression coefficients of multivariable logistic regression analysis revealed that brevity of enhancement increased and normalized perfusion area under curve decreased with presence of active fistulas (p = 0.03 and p = 0.04, respectively). By cross-validation, a logistic regression model that included quantitative perfusion parameters (DCE and IVIM) performed significantly better than IVIM only (p < 0.001). Area under the curves for distinguishing patients with active from those with inactive fistulas were 0.669 (95% confidence interval [CI]: 0.500, 0.838) for a model with IVIM only, 0.860 (95% CI: 0.742, 0.977) for a model with IVIM and brevity of enhancement, and 0.921 (95% CI: 0.846, 0.997) for a model with IVIM and all DCE parameters.

Conclusion

The inclusion of brevity of enhancement measured by DCE-MRI improved assessment of anal fistula activity over IVIM-DWI only.

Perianal fistulizing Crohn's disease: pathogenesis, diagnosis and therapy

Perianal fistulizing Crohn's disease has a major negative effect on patient quality of life and is a predictor of poor long-term outcomes. Factors involved in the pathogenesis of perianal fistulizing Crohn's disease include an increased production of transforming growth factor β, TNF and IL-13 in the inflammatory infiltrate that induce epithelial-to-mesenchymal transition and upregulation of matrix metalloproteinases, leading to tissue remodelling and fistula formation. Care of patients with perianal Crohn's disease requires a multidisciplinary approach. A complete assessment of fistula characteristics is the basis for optimal management and must include the clinical evaluation of fistula openings, endoscopic assessment of the presence of proctitis, and MRI to determine the anatomy of fistula tracts and presence of abscesses. Local injection of mesenchymal stem cells can induce remission in patients not responding to medical therapies, or to avoid the exposure to systemic immunosuppression in patients naive to biologics in the absence of active luminal disease. Surgery is still required in a high proportion of patients and should not be delayed when criteria for drug failure is met. In this Review, we provide an up-to-date overview on the pathogenesis and diagnosis of fistulizing Crohn's disease, as well as therapeutic strategies.

The development of a magnetic resonance imaging index for fistulising Crohn's disease

BACKGROUND

Magnetic resonance imaging (MRI) is the gold standard for assessment of perianal fistulising Crohn's disease (CD). The Van Assche index is the most commonly used MRI fistula index.

AIMS

To assess the reliability of the Van Assche index, and to modify the instrument to improve reliability and create a novel index for fistulising CD.

METHODS

A consensus process developed scoring conventions for existing Van Assche index component items and new items. Four experienced radiologists evaluated 50 MRI images in random order on three occasions. Reliability was assessed by estimates of intraclass correlation coefficients (ICCs). Common sources of disagreement were identified and recommendations made to minimise disagreement. A mixed effects model used a 100 mm visual anologue scale (VAS) for global severity as outcome and component items as predictors to create a modified Van Assche index.

RESULTS

Intraclass correlation coefficients (95% confidence intervals) for intra-rater reliability of the original and modified Van Assche indices and the VAS were 0.86 (0.81-0.90), 0.90 (0.86-0.93) and 0.86 (0.82-0.89). Corresponding ICCs for inter-rater reliability were 0.66 (0.52-0.76), 0.67 (0.55-0.75) and 0.58 (0.47-0.66). Sources of disagreement included number, location, and extension of fistula tracts, and rectal wall involvement. A modified Van Assche index (range 0-24) was created that included seven component items.

CONCLUSIONS

Although "almost perfect" intra-rater reliability was observed for the assessment of MRI images for fistulising CD using the Van Assche index, inter-rater reliability was considerably lower. Our modification of this index should result in a more optimal instrument.

Magnetic resonance imaging may predict deep remission in patients with perianal fistulizing Crohn's disease

AIM

To evaluate the imaging course of Crohn’s disease (CD) patients with perianal fistulas on long-term maintenance anti-tumor necrosis factor (TNF)-α therapy and identify predictors of deep remission.

METHODS

All patients with perianal CD treated with anti-TNF-α therapy at our tertiary care center were evaluated by magnetic resonance imaging (MRI) and clinical assessment. Two MR examinations were performed: at initiation of anti-TNF-α treatment and then at least 2 years after. Clinical assessment (remission, response and non-response) was based on Present’s criteria. Rectoscopic patterns, MRI Van Assche score, and MRI fistula activity signs (T2 signal and contrast enhancement) were collected for the two MR examinations. Fistula healing was defined as the absence of T2 hyperintensity and contrast enhancement on MRI. Deep remission was defined as the association of both clinical remission, absence of anal canal ulcers and healing on MRI. Characteristics and imaging patterns of patients with and without deep remission were compared by univariate and multivariate analyses.

RESULTS

Forty-nine consecutive patients (31 females and 18 males) were included. They ranged in age from 14-70 years (mean, 33 years). MRI and clinical assessment were performed after a mean period of exposure to anti-TNF-α therapy of 40 ± 3.7 mo. Clinical remission, response and non-response were observed in 53.1%, 20.4%, and 26.5% of patients, respectively. Deep remission was observed in 32.7% of patients. Among the 26 patients in clinical remission, 10 had persisting inflammation of fistulas on MRI (T2 hyperintensity, n = 7; contrast enhancement, n = 10). Univariate analysis showed that deep remission was associated with the absence of rectal involvement and the absence of switch of anti-TNF-α treatment or surgery requirement. Multivariate analysis demonstrated that only the absence of rectal involvement (OR = 4.6; 95%CI: 1.03-20.5) was associated with deep remission.

CONCLUSION

Deep remission is achieved in approximately one third of patients on maintenance anti-TNF-α therapy. Absence of rectal involvement is predictive of deep remission.

New horizons in the imaging of perianal Crohn's disease: transperineal ultrasonography

perianal disease, most commonly manifest as fistula or abscess formation, affects up to 40% of patients with crohn's disease. perianal crohn's disease is disabling, associated with poor outcomes, and represents a therapeutic challenge for physicians. correct diagnosis and classification of perianal disease is the first crucial step for appropriate multidisciplinary management. Areas covered: A literature search was performed of the PubMed database using the terms 'transperineal ultrasonography', 'transperineal ultrasound', 'perianal disease', 'perianal fistula', 'perianal abscess', 'magnetic resonance', 'endoanal ultrasonography', 'endoscopic ultrasound' in combination with 'Crohn's disease'. A comprehensive review of the relative advantages and disadvantages of the various methods of evaluation of perianal Crohn's disease is provided. A particular focus is placed on transperineal ultrasonography, including historical and technical factors, advantages and limitations, and its current role in practice. An algorithm for integration of transperineal ultrasound into the management of perianal Crohn's disease into clinical practice is proposed, along with future areas research. Expert commentary: Transperineal ultrasound is a simple, safe, cheap and reliable imaging technique for evaluation of perianal Crohn's disease, which should be used more frequently in clinical practice.

Advances in Use of Endoscopy, Radiology, and Biomarkers to Monitor Inflammatory Bowel Diseases

Crohn's disease and ulcerative colitis are heterogeneous inflammatory bowel diseases, and therapeutic requirements vary among patients. We have a limited capacity to predict disease progression for individual patients, therefore it is important that they are evaluated for the presence of active disease when symptoms are mild or even absent, when patients are more likely to respond to new treatment interventions. It then is important to monitor responses to treatment, to quickly identify those therapies that are ineffective, modify or change therapy, and avoid disease complications. Studies are underway to assess the effects of different monitoring strategies. Because of the heavy burden of severe inflammatory bowel disease on patients' health and quality of life, and the association between intestinal healing and disease progression in high-risk patients, a treat-to-target strategy (based on tissue healing) is likely to be optimal.

Evolving Concepts in Phases I and II Drug Development for Crohn's Disease

The highest attrition rates during drug development programmes occur at the proof of concept stage. Given the large number of molecules under development for Crohn's disease, a need exists to improve the efficiency of early drug development by fast-tracking promising agents and terminating ineffective ones. Multiple opportunities are available to achieve these goals, including the use of more responsive outcome measures, and the incorporation of sophisticated pharmacokinetic modelling and/or highly specific pharmacodynamic markers into exposure-based dosing regimens and novel trial designs. In this article we review these strategies and propose an integrated paradigm of early drug development in Crohn's disease.

MRI characteristics of proctitis in Crohn's disease on perianal MRI

Purpose

Multiple features have been described for assessing inflammation in Crohn’s disease (CD) in MR enterography, but have not been validated in perianal magnetic resonance imaging (MRI). Retrospectively, we studied which MRI features are valuable in assessing proctitis.

Materials and methods

CD patients (≥18 years) who underwent colonoscopy (reference standard) and perianal fistula MRI within 8 weeks were included. Seventeen MRI features were blindly scored by three observers and correlated to endoscopy (regression analysis). Reproducibility (multirater kappa, intraclass correlation coefficient) was determined for all three observer pairs. MRI features were considered relevant when significantly correlated to endoscopy for ≥2 observers, and reproducibility was ≥0.40 for ≥2 observer pairs.

Results

Perianal MRI of 58 CD patients were included. Wall thickness, rectal mural fat, creeping fat, and size of mesorectal lymph nodes showed a significant correlation with endoscopy for ≥2 observers (p = 0.000–0.023, p = 0.011–0.172, p = 0.007–0.011 and p = 0.000–0.005, respectively) with a kappa/intraclass correlation coefficient of ≥0.60 for ≥2 observer pairs. Perimural T2 signal and perimural enhancement significantly correlated to endoscopy (all p values ≤0.05) for all three observers and the reproducibility was ≥0.40 for ≥2 observer pairs. Mural T2 signal and degree and pattern of T1 enhancement showed significant correlation to endoscopy for two observers, but with poor to moderate reproducibility.

Conclusion

Wall thickness, mural fat, and mesorectal features (perimural T2 signal, perimural enhancement, creeping fat, and size of mesorectal lymph nodes) had significant correlation to endoscopy and were reproducible in diagnosing proctitis. Some established luminal features in MRE were considered not useful.

Results of the Fifth Scientific Workshop of the ECCO [II]: Clinical Aspects of Perianal Fistulising Crohn's Disease-the Unmet Needs

BACKGROUND AND AIMS

Perianal fistulas affect up to one-third of Crohn's patients during the course of their disease. Despite the considerable disease burden, current treatment options remain unsatisfactory. The Fifth Scientific Workshop [SWS5] of the European Crohn's and Colitis Organisation [ECCO] focused on the pathophysiology and clinical impact of fistulas in the disease course of patients with Crohn's disease [CD].

METHODS

The ECCO SWS5 Working Group on clinical aspects of perianal fistulising Crohn's disease [pCD] consisted of 13 participants, gastroenterologists, colorectal surgeons, and a histopathologist, with expertise in the field of inflammatory bowel diseases. A systematic review of literature was performed.

RESULTS

Four main areas of interest were identified: natural history of pCD, morphological description of fistula tracts, outcome measures [including clinical and patient-reported outcome measures, as well as magnetic resonance imaging] and randomised controlled trials on pCD.

CONCLUSIONS

The treatment of perianal fistulising Crohn's disease remains a multidisciplinary challenge. To optimise management, a reliable classification and proper trial endpoints are needed. This could lead to standardised diagnosis, treatment, and follow-up of Crohn's perianal fistulas and the execution of well-designed trials that provide clear answers. The prevalence and the natural history of pCD need further evaluation.

Management of perianal fistulas in Crohn’s disease: An up-to-date review

Perianal disease is one of the most disabling manifestations of Crohn’s disease. A multidisciplinary approach of gastroenterologist, colorectal surgeon and radiologist is necessary for its management. A correct diagnosis, based on endoscopy, magnetic resonance imaging, endoanal ultrasound and examination under anesthesia, is crucial for perianal fistula treatment. Available medical and surgical therapies are discussed in this review, including new local treatment modalities that are under investigation.

Magnetic resonance imaging and clinical assessments for perianal Crohn's disease: gain and limits

BACKGROUND

Assessment of perianal Crohn's disease remains challenging. European Crohn's and Colitis Organisation (ECCO) recommend magnetic resonance imaging (MRI) as a gold standard, but both accuracy and advantages remain limited compared to systematic clinical assessment. The aim of this study was to define their actual diagnostic value.

METHODS

We performed a retrospective analysis of a prospective database of consecutive patients with perianal Crohn's disease assessed by magnetic resonance imaging and clinical examination from 2006 to 2012. At each outpatient visit, perianal activity (Perianal Disease Activity Index) and perianal phenotype (Cardiff-Hughes classification) were noted. MRI was interpreted according to Cardiff-Hughes and Van Assche classifications.

RESULTS

Overall, 122 combined evaluations were assessed in 70 patients. Radiological imaging failed to show superficial ulcerations in 20/21 patients (95%) and severe ulcerations in 13/15 patients (87%). It consistently failed to diagnose anal stenosis (n=21, 100%). For fistulising lesions, the global agreement between the two methods was 71/122 (58%) in assessing complex fistulas. Clinical assessment underestimated 44/68 (65%) of multiple or ramified fistula tracts. Clinical examination failed to diagnose half of the radiological abscesses.

CONCLUSIONS

Current ECCO guidelines should be applied with some caution because of the low sensitivity of MRI for the diagnosis of non-fistulising perianal disease. Combining clinical and MRI assessments improves diagnostic accuracy.

A global consensus on the classification, diagnosis and multidisciplinary treatment of perianal fistulising Crohn's disease

OBJECTIVE

To develop a consensus on the classification, diagnosis and multidisciplinary treatment of perianal fistulising Crohn's disease (pCD), based on best available evidence.

METHODS

Based on a systematic literature review, statements were formed, discussed and approved in multiple rounds by the 20 working group participants. Consensus was defined as at least 80% agreement among voters. Evidence was assessed using the modified GRADE (Grading of Recommendations Assessment, Development, and Evaluation) criteria.

RESULTS

Highest diagnostic accuracy can only be established if a combination of modalities is used. Drainage of sepsis is always first line therapy before initiating immunosuppressive treatment. Mucosal healing is the goal in the presence of proctitis. Whereas antibiotics and thiopurines have a role as adjunctive treatments in pCD, anti-tumour necrosis factor (anti-TNF) is the current gold standard. The efficacy of infliximab is best documented although adalimumab and certolizumab pegol are moderately effective. Oral tacrolimus could be used in patients failing anti-TNF therapy. Definite surgical repair is only of consideration in the absence of luminal inflammation.

CONCLUSIONS

Based on a multidisciplinary approach, items relevant for fistula management were identified and algorithms on diagnosis and treatment of pCD were developed.

Magnetic resonance imaging of perianal fistulas

Perianal fistulization is the result of a chronic inflammation of the perianal tissues. A wide spectrum of clinical manifestations, ranging from simple to complex fistulas, can be seen, the latter especially in patients with Crohn disease. Failure to detect secondary tracks and hidden abscesses may lead to therapeutic failure, such as insufficient response to medical treatment and relapse after surgery. Currently, magnetic resonance (MR) imaging is the preferred technique for evaluating perianal fistulas and associated complications. Initially used most often in the preoperative setting, MR imaging now also plays an important role in evaluating the response to medical therapy.

MRI-based score helps in assessing the severity and in follow-up of pediatric patients with perianal Crohn disease

OBJECTIVES

The radiologic healing of perianal fistulizing Crohn disease (PfCD) lags behind the clinical healing. Contrast-enhanced pelvic magnetic resonance imaging (MRI) is the radiologic study of choice used to diagnose PfCD in children. The aim was to study whether the various MRI-based radiologic parameters and score can help in staging and follow-up of patients with PfCD.

METHODS

We performed a retrospective chart review of children with PfCD who underwent contrast-enhanced MRI of the pelvis. The demographic profile, clinical status, and laboratory data of the patients at the time of each MRI examination were noted. Based on the clinical status of the patient at the time of MRI examinations, the MRIs were classified into 3 groups: severe disease, mild-to-moderate disease, and asymptomatic. Each MRI examination was reviewed by a radiologist, who was blinded to the clinical status of the patient.

RESULTS

Of the radiologic parameters, the number of fistulas, the complexity of fistulas, and the number of abscesses were significantly lower in the asymptomatic group compared with the mild-to-moderate and severe disease groups. The Van Assche MRI-based score was significantly lower in the asymptomatic group compared with the mild-to-moderate disease (P = 0.01) and the severe disease group (P = 0.002). The percentage increase in fistula activity after gadolinium administration was significantly lower in the asymptomatic group compared with the mild-to-moderate disease (P = 0.026) and severe disease (P = 0.019) groups. The MRI-based scores were significantly higher in the MRI examinations performed at diagnosis compared with those that were performed while the patients were receiving the treatment (P = 0.017).

CONCLUSIONS

The Van Assche MRI score and the percentage increase in fistula activity after gadolinium administration help in assessing the severity perianal Crohn disease. The Van Assche MRI score may be helpful in documenting healing during therapy of perianal Crohn disease.

Investigation of small bowel in pediatric Crohn's disease

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