Bowel Wall Thickening Research Articles

P676 Intestinal ultrasound accurately predicts therapy failure in Crohn's disease patients during a biologics-induced remission

Abstract Background Intestinal Ultrasound (IUS) is a non-invasive modality that can assess disease activity, complications, and treatment follow-up in Crohn's disease (CD) patients. IUS is reliable, patient-friendly, and allows frequent monitoring of disease activity. While 3mm bowel wall thickness (BWT) was repeatedly found to correlate with intestinal inflammation, whether this threshold also best predicts clinically relevant future outcomes is still largely unknown. We aim to investigate the role of IUS to predict the risk of therapy failure in biologics-treated CD patients in clinical remission. Methods Our analysis included a retrospective cohort of CD patients in clinical remission (HBI≤4) induces by biologic drugs, who underwent IUS 12 (±2) months after induction. We examined the correlation of IUS activity parameters with future therapy failure (defined as drug discontinuation, dose escalation, new corticosteroid use, CD-related hospitalization, or surgery). Results A total of 57 patients (58% male), with ileal (65%) or ileocolonic (35%) CD, on biological therapy (28% infliximab, 51% adalimumab, 10.5% vedolizumab, 10.5% ustekinumab) were included. Therapy failure occurred in 54.3% (32.2% drug discontinuation, 45.2% dose escalation, 16.2% corticosteroid use and 6.4% hospitalization) during a median follow-up of 12 (IQR 5-22) months after IUS. Of all IUS parameters examined, therapy failure was associated only with increased BWT; BWT > 5mm (hazard ratio (HR) 2.3 [confidence interval (CI) 1.03-5.3], p= 0.041). Interestingly, there was risk plateauing with increased BWT above this cutoff (>5.5 mm (HR 2.2 [CI 1-5.10], p=0.048); >6mm (HR 2.6 [CI 1.17-6.12], p=0.019); >6.5 mm (HR 2.5 [CI 1.08-5.83], p=0.032)) (Figure 1). A BWT cutoff of 3mm could not discriminate patients with future treatment failure. Conclusion Our findings suggest that BWT of > 5 mm during clinical remission can predict subsequent treatment failure in CD patients treated with biologics. Our results support the use of IUS in monitoring CD during remission, and may point to a novel threshold predicting disease reactivation.

P594 Bowel ultrasound is useful in predicting relapse in patients with Ulcerative Colitis in remission

Abstract Background Endoscopic remission is associated with better long-term outcomes of ulcerative colitis (UC), and therefore, it is considered a treatment target. However, endoscopy is invasive and frequent monitoring is not feasible. We have reported that bowel ultrasound (BUS) is useful in predicting endoscopic and histologic severity and in determining response to treatment (Sagami S et al, APT 2020 & 2022). However, it is unclear whether BUS can predict the relapse of UC in remission. Methods We conducted a retrospective cohort study enrolling UC patients who underwent BUS from Jul 2018 to Jul 2021 during clinical remission (Patient Reported Outcome-2 ≦ 1 and no rectal bleeding) for at least 3 months and followed for 1 year. Spearman rank correlation coefficient was used to analyse the correlation between BUS and Mayo endoscopic subscore (MES) (evaluation of the most severe part of the colon). The association between BUS findings (bowel wall thickness (BWT), bowel wall flow (BWF), bowel wall stratification (BWS), enlarged lymph nodes), Milan Ultrasound Criteria (MUC = 1.4 × colonic BWT + 2 × colonic BWF (0 = absence, 1 = presence of colour Doppler signal)) (Allocca M et al, UEGJ 2021), MES, CRP and faecal calprotectin (FC) and subsequent clinical relapse was evaluated. Relapse was defined as rectal bleeding score ≧ 1, stool frequency score ≧ 2, or treatment intensification for symptoms. Results A total of 58 patients were included in the study. The median age was 46 years, 37 (63.8%) were male, 39 (67.2%) were pancolitis, and the median disease duration was 116 months. BWT and BWF were moderately correlated with MES but MUC showed a numerically highest coefficiency (0.61) when evaluated for the colon. Overall, 18 patients (31.0%) relapsed within 1 year. Neither BWT, BWF, BWS, enlarged lymph nodes, nor CRP was predictive for relapse. The log-rank test showed MUC > 6.2 (p = 0.019), MES ≥ 1 (p = 0.013), and FC ≥ 250 μg/g (p = 0.040) were associated with a shorter time to relapse. Cox proportional hazards model showed MUC > 6.2 (HR 3.22: 95%CI 1.14-9.08, p = 0.027), MES ≥1 (HR 8.70: 95%CI 1.11-68.1, p = 0.040) had a higher risk of relapse in 1 year. Sensitivity, specificity, PPV, and NPV of MUC > 6.2 for relapses of different time points (3, 6, and 12 months) showed high specificity of 0.90-0.91 and NPV of 0.74-0.90. Interestingly, 4 out of 9 patients with MUC > 6.2 relapsed within 3 months, suggesting MUC > 6.2 is a risk of short-term relapse. Conclusion BUS in UC patients in remission can predict relapse using MUC. In particular, the MUC score ≤ 6.2 is associated with a lower risk of relapse and could be a treatment-target alternative to endoscopic healing.

P499 Exclusive enteral nutrition induces transmural healing in adults with active Crohn’s disease

Abstract Background Exclusive enteral nutrition (EEN) is a nutrition-based therapy for active Crohn’s Disease (CD). Transmural healing is a novel therapeutic paradigm in CD, holding benefit beyond endoscopic mucosal healing. There are limited data exploring EEN and transmural healing in CD. We aimed to examine the effect of EEN on inducing transmural response and healing as assessed by intestinal ultrasonography (IUS). Methods This was a prospective, multi-centre, open-label cohort study. Adults ≥18 years with active CD were enrolled between March to September 2022. Eligible, consenting participants were nutritionally assessed by a specialised IBD dietitian and prescribed 6 weeks of EEN therapy. A 1.5kcal/ml polymeric, low lactose, fibre-free formula was used and EEN prescriptions were personalised to 25-30kcal/kg IBW and 1.2-1.5g protein/kg IBW/day. Patients were allowed concurrent tapering corticosteroid therapy and biological therapy. Participants completed clinical, biochemical and nutritional assessments at weeks 0, 3 and 6 and IUS at weeks 0 and 6. This included Harvey Bradshaw Index (HBI), C-Reactive protein, faecal calprotectin (FCP), body mass index (BMI). IUS assessment was conducted at baseline and at week 6 and images were centrally read by a blinded, IUS-trained gastroenterologist. Transmural response was defined by ≥25% bowel wall thickness (BWT) reduction from baseline. Transmural healing was defined as BWT≤3mm, Doppler signal score≤1, normal bowel wall stratification, and absence of inflammatory fat. Results Fourteen patients, 9 were female (64.3%) and mean age of 44.4 years, were consecutively enrolled and completed 6-weeks of EEN therapy. Ten patients (71.4%) had ileal disease (L1), 4/10 had ileocolonic (L3) and predominant phenotype was inflammatory (B1, 7/14) and stricturing (B2, 6/14) disease. Mean disease activity was HBI 5.1±4.0.Two patients had perianal disease (14.3%). Nine patients (64.3%) reported 100% adherence and 4 patients (28.6%) reported 75-99% adherence to the exclusive diet by predefined adherence categories. At week 6, 11/14 (78.6%) of patients achieved clinical remission with 12/14 (85.7%) showing clinical response. Reductions in CRP and FCP were not statistically significant. Numerical reduction in BWT was observed 5.6±1.4mm vs 4.8±2.1mm (95% CI -1.94, 0.265, p = 0.124). Transmural response was achieved in 8/14 (57.1%) and transmural healing was reached in 2 (14.3%) patients. Most common side effect was constipation (42.9%). Conclusion EEN was identified to induce early transmural response and healing in patients with active CD. Further studies are required to evaluate the capacity for EEN to induce transmural healing and the role of IUS as an early assessment tool in monitoring therapeutic response in CD.

P357 Intestinal ultrasound as a promising non-invasive monitoring tool in patients with Ulcerative Colitis

Abstract Background Intestinal ultrasound (IUS) is an established non-invasive tool for monitoring disease activity in Crohn’s disease, however its value in ulcerative colitis (UC) is still less clear. Our goal was to correlate IUS features with well-established disease targets in UC. Methods Prospective study including patients with left-sided (E2) or extensive (E3) UC. Simple Clinical Colitis Activity Index (SCCAI), patient reported outcomes (PRO-2), C-reactive protein (CRP), fecal calprotectin (FCal) and endoscopic activity (Mayo endoscopic subscore - sMayo) were evaluated. IUS features included bowel wall thickness (BWT) and color Doppler flow (CDF), assessed by modified Limberg score. The most affected segment was selected for analysis. Clinical remission was defined by SCAAI ≤ 2, endoscopic remission by sMayo of 0 and IUS remission by BWT ≤ 3 mm and CDF=0. Results 17 UC patients (59% males, median age 44 (20-68) years, 53% E3) were included and evaluated in 46 different time-points, with concomitant endoscopic assessment in 31 cases. Overall, 55% were in clinical remission, 30% in endoscopic remission and 22% in IUS remission. The sigmoid colon was the most affect segment by IUS (46%) and endoscopy (39%). Median BWT in the most affected segment was 4.28 (3.08-6.25) mm and 83% had a Limberg score ≥ 1. Median CRP was 0.41 (0.06-18.55) mg/dL and FCal 80 (3-8000) ug/g. There was a moderate agreement between IUS and endoscopy regarding the most affected segment (k=0.43, p<0.001). BWT showed a strong correlation with sMayo and CRP and a moderate correlation with FCal, SCCAI and PRO-2. CDF showed no significant correlations with clinical, biochemical and endoscopic features (Table 1). Patients with IUS remission presented higher rates of endoscopic remission (78% vs 10%, p<0.001) and lower sMayo scores (0 vs 2, p<0.001), together with lower FCal (21 vs 133 ug/g, p=0.01) and CRP levels (0.08 vs 0.54, p<0.01). Conclusion IUS features showed a significant correlation with endoscopic activity, clinical activity and biomarkers. IUS remission was associated with endoscopic remission and lower biomarker activity, suggesting that IUS is an accurate method to evaluate UC patients both with active disease and in remission.

P370 Correlation of the IBD Disk with intestinal ultrasound in patients with inflammatory bowel disease

Abstract Background The Inflammatory Bowel Disease (IBD) Disk represents a self-administered questionnaire that can facilitate, in real time, assessment of IBD related disability, and IBD-related daily life burden. Surrogate markers of IBD activity tend to associate with increased disability. Intestinal ultrasound (IUS) is a non-invasive tool that can objectively and accurately define disease activity and complications in IBD patients. We investigated the correlation between IBD-Disk and IUS in IBD patients. Methods We performed a cross-sectional study that included formally diagnosed IBD patients who underwent IUS and subsequently completed the IBD-Disk questionnaire. Active disease on IUS was defined as bowel wall thickness (BWT) >3 mm at the most affected bowel segment. The overall IBD-Disk score was calculated as the sum of its 10 components, ranging from 0 to 100 (best score: 0, worst score: 100). We explored the correlation between IBD-Disk and its components with IUS. We additionally investigated the correlation of IBD-related daily life burden with IUS. (IBD-Disk total score > 40: high IBD related daily life burden vs IBD-Disk total score ≤ 40: low IBD related daily life burden). Results We included 49 patients (table 1), who underwent IUS for disease monitoring (59.2%) and symptoms suggestive of disease flare (40.8%). Median IBD-Disk total score in our cohort was 48 (IQR 18-58). Median IBD-Disk total score was 52 (IQR 47.3-61.5) in IUS active vs 16 (IQR 5-25) in IUS inactive patients (p<0.001). The area under the ROC curve of IBD-Disk total score in predicting IUS activity was 0.88 (95% C.I: 0.77-0.99, p<0.001, Figure 1). IBD-Disk score >31 predicted disease activity in IUS with 90.6% sensitivity and 88.2% specificity. We observed a moderate correlation between IBD-Disk score and BWT (ρ=0.61, p<0.001) as well as between IBD-Disk score and C-reactive protein (ρ=0.66, p<0.001). Among the components of the IBD-Disk, 8/10 manifested a moderate correlation with BWT (table 2). IBD-Disk score > 40 was found in 27/32 (84.4%) of IUS active and 2/17 (11.8%) of IUS inactive patients, while IBD-Disk score ≤ 40 was found in 5/32 (15.6%) of IUS active and 15/17 (88.2%) of IUS inactive patients respectively (p<0.001). Median BWT was 1.95 mm (IQR 1.53-4.40) in patients with IBD-Disk score ≤ 40 and 5.9 mm (IQR 4.8-6.8) in patients with IBD-Disk score > 40 (p<0.001). Conclusion IBD-Disk displayed a significant correlation with IUS evidence of disease activity in IBD patients. Active disease in IUS was significantly correlated with a high IBD-related daily life burden as expressed by IBD-Disk total score > 40. IBD-Disk could be used in clinical practice to evaluate disease activity and severity in IBD patients.

P587 Intestinal ultrasound (IUS) and magnetic resonance imaging (MRI) for monitoring of response to therapy in luminal Crohn’s disease – a systematic review.

Abstract Background Mucosal and transmural healing are associated with better outcomes in Crohn’s disease. Magnetic resonance imaging (MRI) and intestinal ultrasound (IUS) provide non-invasive cross-sectional assessment of disease activity and transmural healing. This systematic review addresses the utility of MRI and IUS in the assessment of disease activity and transmural healing in response to drug therapy when compared to endoscopy in patients with luminal Crohn’s disease. Methods Database searches were undertaken (Medline, Embase, Emcare, APA PsycInfo, CINAHL, Cochrane Library) following the PRISMA statement. Studies with ≥10 luminal Crohn’s disease patients with paired endoscopy and imaging (MRI or IUS) following treatment initiation were included. Records were screened on title and abstract, then full text by two independent reviewers. Results 5760 records were identified, 1707 duplicates removed, 1468 excluded; 2585 screened on title and abstract, 65 underwent full text review, resulting in 24 studies meeting inclusion criteria. 10 studies examined IUS, 12 examined MRI and 2 compared both. There was good correlation between IUS and endoscopic remission with biologic and or thiopurine treatment (k = 0.63, P<0.001; k = 0.73, P<0.001), and good correlation for IUS score and Simple Endoscopic score-Crohn’s disease (SESCD) at baseline and reassessment (r=0.521; P<0.001). Early reduction in bowel wall thickness (BWT) at 4-8 weeks of anti-TNF therapy predicted endoscopic response at 12-38 weeks (AUROC 0.77; OR 10.80 P=0.012). Significant reductions in BWT after 2 weeks of anti-TNF therapy was associated with clinical and endoscopic response at 14 weeks. A significant reduction in BWT as early as 4 weeks with ustekinumab therapy correlated with endoscopic response at 48 weeks (k = 0.21; 95%CI 0.04-0.38). IUS transmural remission rates were higher in colonic disease than terminal ileal disease (OR 2.59; 95%CI 1.43-4.70, P<0.05). MRI MaRIA score had a high accuracy for predicting endoscopic remission (AUROC 0.967; sensitivity 93%, specificity 77%, P<0.05). Intestinal healing detected by MRI and endoscopy after 1 year of anti-TNF was predictive of long-term clinical remission (sensitivity 75%, specificity 72%; P=0.02). The simplified MaRIA score correlates with endoscopic response and was responsive to change after drug therapy (r=0.72; 95%CI 0.53-0.85). Conclusion Intestinal ultrasound and magnetic resonance imaging are reliable non-invasive modalities for assessing transmural healing in Crohn’s disease and accurate in monitoring response to drug therapy. Early changes in ultrasound are predictive of response to treatment. Intestinal ultrasound can monitor response to biologic induction.

P641 Bowel Doppler Signal, the most important ultrasonographic feature in clinical practice in managing Inflammatory Bowel Diseases patients

Abstract Background IBD are chronic diseases that require multiple endoscopic and imaging assessments, being diseases that not only involve a multitude of medical resources but patient compliance too. Bowel ultrasound (BUS) is a useful imaging tool in monitoring inflammatory bowel diseases (IBD) patients. Current guidelines recommend BUS altogether with other cross-sectional imaging methods to diagnose, monitor IBD patients and also for detecting complications and post-surgery recurrence. A multitude of ultrasonographic features are used to describe pathologic findings related to IBD but not all of them are easy to integrate in clinical practice, especially in unexperienced hands. Methods Our study included 117 IBD patients of which 28 were diagnosed with ulcerative colitis and 89 with Crohn’s disease. Diagnosis was established endoscopically and histologically and both patients with active and inactive disease were included. Exclusion criteria consisted in patients with other causes of inflammatory syndrome, patients with solely rectal localization of the disease or a surgical history. Subjects were prospectively evaluated using BUS and several sonographic aspects of the bowel wall were monitored: bowel wall thickness, bowel echo pattern, Doppler signal (DS) presence, hypertrophic mesenteric fat, and the presence of lymph nodes. Biological markers of inflammation were obtained including faecal calprotectin. Patients were followed up for the next 6 months and data regarding treatment intensification was noted. All patients signed an informed consent, and the study was approved by the Ethics Committee of the Fundeni Clinical Institute. Results Significantly higher values of clinical and biological markers were associated with the presence of parietal DS (p<0.0001) suggesting that this BUS feature is an important bowel wall inflammation surrogate. Higher Limberg scores (a subjective Doppler signal score used in BUS) correlated with increased values of biological markers of inflammation (p=0.002). A multivariate analysis showed that DS and a thicker than 5 mm bowel wall were independent predictors of step-up therapy. The presence of parietal DS raised the patient risk of switching therapy 7.6 times, while bowel wall thickness only 2.4 times, making DS the most useful BUS feature in evaluating inflammatory activity and predicting the need for step-up therapy. Conclusion DS is one of the most important BUS features to use in evaluating and monitoring IBD patients and could have a role in disease decision making. This finding should advocate for this imaging method in clinical practice, and even low BUS-experience practitioners are encouraged to use it.

P388 Shear wave elastography predicts short-term response to induction therapy in patients with Crohn’s disease

Abstract Background Endoscopy has been used to assess the disease activity of Crohn's disease (CD) but may not be sufficient considering the transmural nature of its inflammation. Bowel ultrasonography (BUS) has been reported to reflect disease activity of CD and long-term outcomes. We performed a prospective study to determine whether BUS can predict short-term clinical response to induction therapy. Methods Consecutive CD patients with active ulcers in endoscopy requiring induction therapy (Anti-TNF antibody, IL-12/23 p40 antibody, integrin inhibitor, prednisolone) were prospectively enrolled at a single center from October 2018 to July 2022. Short-term clinical response was defined by a reduction of Crohn’s disease activity index > 70 at week 8. Ultrasonographic findings (bowel wall thickness (BWT), colour Doppler signal (CDS), and shear wave elastography (SWE) were recorded for the most severely affected segment at baseline, week 1, and 8 and compared between responders and non-responders. Results Seventeen out of 29 patients were classified as responders at week 8. There was no difference in BWT and CDS at baseline, week 1, and 8 between responders and non-responders (Table 1). In contrast, responders had lower baseline SWE compared with non-responders (2.7±0.3 vs. 3.8±0.3, p=0.02). Adjusted by the prior exposure to biologics, the lower SWE at baseline was associated with clinical response at week 8 (adjusted odds ratio associated with 0.1 m/s increase: 0.9, p=0.018) (Table 2). SWE did not change over time regardless of response for 8 weeks. Conclusion Lower intestinal wall stiffness as measured by SWE is an independent predictor of short-term clinical response.

P246 2D Shear Wave Elastography as novel tool for the assessment of disease severity in patients with IBD

Abstract Background Intestinal Ultrasound (IUS) is a non-invasive modality capable of assessing disease activity in IBD. IUS is reliable, patient-friendly, and allows frequent monitoring of disease activity. Elastography is a measure of tissue stiffness, that is usually studied for the evaluation of intestinal fibrosis in previous studies. However, the addition of elastography to standard IUS for assessing disease severity is still limited. Here we present novel data on the diagnostic value of 2D shear-wave elastography (SWE) in the evaluation of disease severity in patients with IBD. Methods In this prospective descriptive study performed in a single center, consecutive 38 patients with UC and 22 CD were included. Disease activities of UC patients were evaluated by Mayo score and Endoscopic Activity Index (EAI) while Crohn’s Disease Activity Index (CDAI) and Harvey-Bradshaw Index (HBI) evaluated disease activation of CD patients. The bowel wall thickness (BWT) and Limberg score were also measured. The intestinal segment held by an experienced single operator with the 2D-SWE technique was estimated, and its value in kilopascal (kPa) was recorded. Results A statistically significant correlation was found between the stiffness values obtained with SWE, BWT and disease activity scores. Tissue stiffness (kPa) was correlated with HBI (r=0.772, p<0.01), CDAI (r=0.817, p<0.01), C-reactive protein (r=0.503, p=0.02) in CD. In UC, tissue stiffness was correlated with Mayo score (r=0.491, p=0.002), EAI (r=0.481, p=0.003) and C-reactive protein (r=0.423, p=0.009). The correlation of BWT and tissue stiffness was (r=0.797, p<0.05 and 0.698, p<0.05 in CD and UC, respectively). Limberg score was correlated with tissue stiffness values (r=0.743, p<0.05 and r=801, p<0.01 in CD and UC, respectively). The duration of illness was correlated with tissue stiffness values in patients with UC (r=0.665, p<0.05), however it was not correlated in CD patients. Conclusion 2D-SWE is a promising tool in assessing disease activity in patients with CD and UC. Further studies are needed to understand the additive value of elastography in the clinical assessment of patients with IBD.

P225 The accuracy of different intestinal ultrasound parameters in detecting endoscopic activity in patients with inflammatory bowel disease

Abstract Background Intestinal ultrasound (IUS) is considered an accurate tool for assessment of disease activity in inflammatory bowel disease (IBD) patients. We investigated the accuracy of IUS to detect active disease as compared to ileocolonoscopy. Methods We performed a two-center international cross-sectional study that included formally diagnosed IBD patients who underwent IUS and ileocolonoscopy, within a 4 weeks interval. Active disease on IUS was defined as bowel wall thickness (BWT) >3 mm in the most affected bowel segment. Additional IUS parameters evaluated included increase in Doppler color flow in the bowel wall (modified Limberg score > 0), presence of inflammatory fat (FW) and loss of bowel wall stratification (BWS). Active disease at endoscopy was defined as Simple Endoscopic Score for Crohn’s Disease (SES-CD) >2 and Mayo endoscopic score >0. The accuracy of IUS compared to ileocolonoscopy was estimated using sensitivity, specificity, and Cohen’s kappa coefficient analyses. Results We included 85 patients (table 1) performing IUS for disease monitoring (69.4%) and symptoms suggestive of IBD flare (30.6%). Disease was active in IUS in 38/42 (90.5%) of clinically active [Harvey Bradshaw index (HBI) ≥5, Simple Clinical Colitis activity index (SCCAI) >2] and 22/43 (51.2%) of clinically inactive patients (kappa coefficient 0.391, p<0.001). C-reactive protein (CRP) level was 6.95 mg/dl [IQR 2.19-17.75] vs 1.8 mg/dl [IQR 0.85-3.75] in active vs inactive disease on IUS respectively (p<0.001). All patients underwent both endoscopy and IUS, with 63/85 (74.1%) exhibited endoscopic activity. IUS demonstrated 92.1% sensitivity, 90.9% specificity, 96.7% PPV, 80% NPV and kappa coefficient 0.79 in detecting endoscopically active disease (p<0.001). IUS detected 58/63 (92.1%) of endoscopically active cases, and identified the most affected bowel segment in 50/63 (79%) of them. Inability of IUS to identify the most affected bowel segment at endoscopy included rectal involvement (53.8%), complex surgical history (15.38%), stenosis of ileocecal valve (7.69%) and limitations due to obesity (23.07%). Mean BWT of the most affected segment was 4.49 (±1.16) vs 2.33 mm (± 0.63) in endoscopically active vs inactive patients respectively (p<0.001). We furthermore evaluated the accuracy of additional IUS parameters (increased color Doppler flow, FW and loss of BWS) in predicting endoscopic activity (table 2). Conclusion IUS represents a non-invasive tool that can accurately identify disease activity both in Crohn’s disease and ulcerative colitis, when compared to ileocolonoscopy. The most sensitive parameter to detect endoscopic activity was an increased BWT.

P425 The utility of intestinal ultrasound to inform clinical decision making

Abstract Background Inflammatory bowel disease (IBD) is a chronic, immune-mediated disease leading to progressive bowel damage. Objective monitoring is essential to improve outcomes. Intestinal ultrasound (IUS) is an accurate, repeatable modality preferred by patients. The aim of this study was to evaluate changes in medical therapy and further tests requested, when IUS is used routinely to follow patients in an expert centre. Methods This is a single centre, prospective observational cohort study. All recruited provided informed consent with ethics approval through the University of Calgary. Patients over the age of 18 years were recruited via convenience sampling from October 1, 2020 to September 31, 2022. Patients were part of a registry where clinic-based IUS is standard of care. Patient demographics, medical treatment changes and further investigations were recorded. IUS were performed by an IBD gastroenterologist trained in advanced IUS. Patients were classified as symptomatic (Harvey Bradshaw Index [HBI] ≥5) or asymptomatic (HBI<5). IUS were categorised as inactive if the bowel wall thickness (BWT) was <3mm without colour Doppler and inflammatory mesenteric fat) or active (BWT ≥3mm, colour Doppler ≥2 and presence of inflammatory fat). Data were reviewed regarding management: medication changes were defined as dose change, addition of corticosteroids or other medication and medication change. Referral for surgical opinion was recorded. Further outcomes included faecal calprotectin, stool for infection, blood tests, endoscopy, imaging or hospital admission. Results 138 episodes of care were logged including 103(74%) with Crohn’s disease, 16(12%) with ulcerative colitis, 2(1.4%) with IBD-unclassified, 13(9.4%) without IBD investigated for symptoms and 4(2.9%) not recorded. Figure 1 shows symptomatic and active episodes compared to asymptomatic and inactive. IUS were performed: for flare symptoms in 22(16%); for monitoring in 107(78%); or to investigate symptoms in 9(6.5%). IBD medication was escalated in 22(52%) patients with active IUS disease plus symptoms and in 9(39%) asymptomatic patients with active IUS. Medication escalation was performed in 4(16%) symptomatic patients with inactive IUS and 2(4.2%) asymptomatic patients with inactive IUS based on low drug level or adverse events. One patient had medication reduced in frequency due to the IUS findings(Table 1). No hospital admissions occurred following IUS. Conclusion Active IUS triggered treatment modification in almost 40% of patients, regardless of symptoms. Future studies will assess benefits of timely treatment changes for long term outcome. IUS supports a clinician at the bedside to make timely clinical decisions that may avoid invasive testing and decrease resource limited endoscopy.

P314 Microscopic appendicitis in ulcerative colitis: Feasibility of ultrasonographic diagnosis

Abstract Background Increasing evidence suggests appendectomy as potential alternative treatment in patients with ulcerative colitis (UC), especially in those with histological appendiceal inflammation (AI). Intestinal ultrasound (IUS) is a non-invasive diagnostic modality that detects differences in the appendix between UC patients and healthy controls1. This study aimed to correlate appendiceal IUS and endoscopic findings to histopathological inflammation in resection specimens of UC patients undergoing appendectomy. Methods In this prospective cohort study, appendiceal IUS was performed in UC patients undergoing endoscopy and subsequent appendectomy between 2020 and 2022 in a trial for UC (NCT03912714). Primary outcome was the correlation between an increased maximal cross-sectional diameter (MCD, ≥ 6 mm) and AI in patients with a visible appendix on IUS. Presence of AI was assessed in pathology reports. Patients with fibrosis (F) were excluded from IUS analyses. Secondary outcomes included bowel wall thickness (BWT) on IUS and presence of endoscopic peri-appendiceal red patch (PARP) before appendectomy. Results In total, 32 UC patients who underwent laparoscopic appendectomy in study setting were included (84% female, median age 40 [IQR 27-50] years). The majority of patients demonstrated left sided disease (38%) and a mayo score ≥ 2 (88%) on baseline endoscopy. A median window between ultrasound and appendectomy of 1.2 (0.1-2.1) months was found. A total of eighteen (56%) patients were demonstrated to have AI in the resection specimen, and five (16%) patients demonstrated F. The appendix was visualised on IUS in 25 (78%) UC patients, with no difference in patients with AI (AI: 78%, no AI: 78%, p= 1.0). The overall median MCD and BWT were 5.6 [IQR 4.4-6.6] and 2.2 [1.6-2.5] mm, respectively. Patients with AI demonstrated a numerically higher median MCD (AI: [6.0 [4.2-6.8], no AI: 4.9 [4.4-5.8] mm, p= 0.3). Patients with an increased MCD were more likely to demonstrate pathologic AI, although not significant (OR: 6.0, CI 95%: 0.6-63.7, p=0.1). A minority of patients with AI demonstrated to have an endoscopic PARP: 5/18 (28%). The median MCD of patients with PARP was numerically higher (PARP: 6.0 [IQR 4.4-7.8] vs no PARP: 5.5 [4.0-6.6], p=0.5). Conclusion IUS is a feasible modality for assessment of the appendix. Although significance was not reached, patients with an increased MCD were more likely to demonstrate AI. 1Reijntjes MA, de Voogd FAE, et al. Intestinal ultrasound detects an increased diameter and submucosal layer thickness in the appendix of patients with ulcerative colitis compared to healthy controls - a prospective cohort study. Aliment Pharmacol Ther. 2022 Nov 1.

P767 Intestinal ultrasonography predicts short term clinical remission in patients with moderate-to-severe ulcerative colitis

Abstract Background Intestinal ultrasonography (IUS) is a non-invasive, easily accessible and low-cost procedure to visualize the colon and determine disease activity, extent and treatment response in IBD. Our aim was to investigate whether ultrasonographic parameters predict short-term clinical remission in ulcerative colitis (UC). Methods Consecutive patients (pts) with moderate-to-severe UC (total Mayo score>6) starting biological therapies or small molecules were included. Patients were evaluated at baseline by clinical, biochemical, endoscopic (endoscopic Mayo score), and IUS assessments. IUS, doppler and elastographic parameters assessed at baseline before starting therapy were: bowel wall thickening (BWT), echopattern, blood flow (adapted Limberg’ score), Milan Ultrasound criteria (MUC) and shear wave elastography values. The most affected colonic segment was used for all imaging assessments. Clinical remission at 3 months was defined as partial Mayo Score=0-1. Predictive factors of clinical remission at 3 months were analyzed by logistic regression. ROC curve analysis was used to identify the best cut-off of BWT in predicting clinical remission. Results Thirty-one UC pts were enrolled (12 males [39%]; median age: 45 years, range 18-72; median disease duration: 108 months, range 3-312). Sixteen per cent of pts had left colitis and 84% had extensive UC according to the Montreal criteria. Forty-eight per cent of pts were treated with Anti-TNFs, 39% with vedolizumab, 10% with ustekinumab and 3% with tofacitinib. At baseline, 84% of patients had moderate disease and 16% severe disease according to the total Mayo score. A lower total Mayo score and partial mayo score at baseline were predictive of clinical remission at 3 months after starting biological therapy or small molecules than endoscopic Mayo score (OR 0.58, 95% CI 0.33-0.99, p=0.03; OR 0.55, 95% CI 0.29-0.99, p=0.037; OR 0.57, 95% CI 0.16-1.93, p=0.36, respectively; Figure 1, panels A-C). A lower BWT, Limberg’ score and MUC at baseline were predictive of clinical remission at 3 months (OR 0.19, 95% CI 0.05-0.72, p=0.0023; OR 0.22, 95% CI 0.06-0.77, p=0.004; OR 0.48, 95% CI 0.21-0.83, p=0.001, respectively; Figure 1, panels D-F). The most accurate cut-off value of BWT for predicting clinical remission was <6 mm with sensitivity and specificity of 70% and 82%, respectively (Figure 1, panel G). Conclusion IUS easily predicts early clinical remission in patients with moderate-to-severe UC after therapy.

P387 Different rate of transmural remission between first and second line of biologic treatment in Crohn's disease

Abstract Background Transmural remission in Crohn’s disease (CD) has been associated with improved long-term clinical outcomes including reduced hospitalization, surgery, escalation of treatment, and a decrease in clinical relapse over endoscopic remission alone. Albeit transmural remission rate (TRR) in CD patients treated with anti-TNF drugs in first line has been well explored, data on TRR using vedolizumab (VDZ) or ustekinumab (UST) as second-line therapy for CD are still scarce. The aim of this study was to evaluate the TRR in CD patients in maintenance treatment, comparing adalimumab (ADA) in first line with VDZ/UST in second line. Methods From 2018 to 2021 we performed a real world observational longitudinal study evaluating the TRR in all consecutive CD patients in a 2-years maintenance treatment with ADA in first line compared with those treated by VDZ or UST in second line. HBI, fecal calprotectin (FC), SES-CD, and bowel wall thickness (BWT) at ultrasound were analyzed in all patients at the baseline (T0) and after 2 years of maintenance treatment (T1). Clinical remission was defined when HBI was <4. Endoscopic remission was defined when SES-CD was <2. Transmural remission was defined when BWT was <3 mm at a “per-patient” analysis. In accordance with recent literature, laboratory remission was defined when FC was <94 ug/gr. Results One hundred and forty-one CD patients (78 ADA, 31 VDZ, 32 UST) were included in the study. At T1, transmural remission rate was recorded in 39.7% of CD patients treated in first line with ADA, and in 22.5% and 18.7% for VDZ and UST, respectively, in second line (ADA vs VDZ/UST: p<0.05; VDZ vs UST: p 0.7). Endoscopic remission rate was 50% for patients treated in first line with ADA, and 32.2% and 31.2% for second line VDZ and UST, respectively (ADA vs VDZ/UST: p<0.05; VDZ vs UST: p 0.9). Laboratory remission rate was 53.8% for patients treated in first line with ADA, and 29% and 37.5% for VDZ and UST in second line, respectively (ADA vs VDZ/UST: p<0.05; VDZ vs UST: p 0.4). Clinical remission rate was 58.9% for patients treated in first line with ADA, and 45.1% and 40.6% for second line VDZ and UST, respectively (ADA vs VDZ/UST: p=0.057; VDZ vs UST: p=0.7). Conclusion Our findings showed that in CD patients in maintenance treatment with biologics, ADA in first line showed a higher TRR compared with VDZ/UST in second line. Moreover, VDZ and UST showed similar TRR and other outcomes when used in second line.

P411 Early ultrasound assessment predicts therapy response: an easy tool for clinical decision making

Abstract Background Intestinal ultrasound (IUS) is an effective and easy-to-use tool in monitoring Crohn’s disease (CD) lesions during different biological therapies. Aim of our study was to evaluate whether lesion improvement during biological therapy could predict transmural healing. Methods We performed a prospective study enrolling CD patients (pts) with indication to biological therapies. IUS and doppler US parameters at baseline, at 3 and 12 months were: bowel wall thickening (BWT), lesion length, echopattern, complications, blood flow according to Limberg’ score. Transmural healing (TH) was defined as normalization of all parameters; IUS responders were defined as pts with improvement of BWT associated with decreased lesion length, Limberg’ score improvement, and no worsening of the other parameters. Delta (Δ) signified the difference between IUS parameters at baseline and at 3 months. Changes in parameters and in Δ values at baseline and after 3 months were analyzed using Mann Whitney test; the area under (a ROC) curve was calculated. Differences between combination of parameters were tested by Chi-square test. Results One hundred and fifteen CD pts were enrolled (63.5% males; median age 37 years; median disease duration 96 months). Forty-nine per cent of pts had L1, 9% had L2, 42% had L3 according to the Montreal criteria. TH rate at 12 months was 20% and IUS responder rate was 43%. At baseline, no statistical differences in terms of BWT were observed between pts achieving TH vs no TH. Similarly, no differences were observed in pts defined as IUS responders vs non responders. Patients achieving TH at 12 months had a higher ΔBWT than patient without TH (p=0.0004). On ROC curve, ΔBWT improvement of 1.25 mm showed sensitivity and specificity of 73% and 61%, respectively, in predicting pts who achieved TH. Similarly, IUS responder group at 12 months had a higher ΔBWT than patients IUS non-responder group (p<0.0001). On ROC curve, ΔBWT improvement of 1.25 mm showed sensitivity and specificity of 83% and 57%, respectively, in predicting IUS responders. A combination of a ΔBWT (≥1 mm) and Limberg’ score improvement (1 point) was associated with a higher risk of TH at 12 months (p=0.0007; OR 5.1; 95% CI, 1.8-12.8). A combination of a ΔBWT (≥1 mm) and Limberg’ score improvement (1 point) was associated with a higher risk of IUS responders at 12 months (p<0.0001; OR 15.7; 95% CI, 4.5-52). Conclusion An early ΔBWT, and a combination of a ΔBWT and Limberg’ score improvement showed high diagnostic accuracy in predicting pts who achieved TH and IUS responder at 12 months. This information may help clinical decision making in terms of prompt optimization or switching/swapping therapies in CD.

P338 Transmural healing is not associated with less disability than complete endoscopic mucosal healing: a prospective study in a patient with Crohn's disease

Abstract Background Crohn's disease (CD) is associated with disability by affecting physical and emotional well-being, and by altering social interactions. In the era of treat to target, endoscopic remission has become the therapeutic target to prevent parietal destruction and disability. A deeper remission such as transmural healing would reduce long-term complications related to CD. The impact of transmural healing on disability is currently unknown. Methods We conducted a monocentric cross-sectional study between September 2019 and January 2022. Patients followed for CD in endoscopic remission (CDEIS <4) who underwent within < 4 weeks an intestinal ultrasound (IUS) and a disability assessment by an IBD-disk were consecutively included. Four groups were considered: (A) transmural healing defined by the combination of complete endoscopic healing (CDEIS=0) and ultrasound healing (bowel wall thickness (BWT) less than 3 mm), (B) complete endoscopic healing, (C) ultrasound healing and (D) no healing. Moderate to severe disability was defined as an overall score ≥ 40. Results A total of 85 patients were included. Forty-four (51.7%) were female, the median age and disease duration were respectively 38 years (interquartile range [IQR], 33-44) and 12.0 years (IQR, 5-20). There was no difference between the four groups in terms of age, sex, BMI, smoking status, disease location or phenotype or number of biologics failure. The median global IBD-Disk score was 25 (IQR, 9-41) and 24 patients (28.2%) had moderate to severe disability. Transmural healing (group A) was observed in 40 patients (47.1%). Moderate to severe disability was identified in 17.5% (7/40) of patients with transmural healing, 25% (4/16) with endoscopic healing, 44.4% (8/18) with ultrasound healing and 45.4 % (5/11) without healing. In univariate analysis, transmural healing reduced the risk of severe disability (group C vs A OR = 3.77, 95% CI [1.10, 13.45], p = 0.035), group D vs A OR = 3 .75, 95% CI [0.91, 17.12], p=0.063). There was no difference in terms of severe disability between patients with transmural healing and complete endoscopic healing (group B versus A OR = 1.57 95% CI [0.36, 6.23], p = 0.525). Conclusion Transmural healing did not provide any benefit in terms of disability compared to complete endoscopic healing. Mucosal healing therefore remains the objective to be achieved in order to reduce the risk of short-term disability.

P749 Crohn’s disease stricture response and resolution with adalimumab therapy demonstrated with intestinal ultrasound. The STRIDENT randomised trial

Abstract Background Transmural healing is a treatment goal in the management of Crohn’s disease, and intestinal ultrasound (IUS) is potentially a sensitive, non-invasive and reproducible means to assess the response to treatment. Methods The STRIDENT (Stricture Definition and Treatment) study was a randomised controlled trial of standard dose monotherapy adalimumab versus intensive high-dose adalimumab combined with a thiopurine. Crohn’s disease patients with symptomatic intestinal strictures were randomised 2:1 to high dose adalimumab induction (160mg weekly for 4 weeks) with 40mg fortnightly maintenance plus thiopurine, with possible dose escalation at 4 and 8 months, versus standard dose adalimumab monotherapy. The primary endpoint was clinical response, defined as a reduction in the Obstructive Symptom Score (OSS) of ≥1, at 12 months. IUS was performed at baseline, 4, 8 and 12 months. IUS endpoints included stricture resolution (normalisation of pre-stenotic dilation (<2.5cm); reduced stricture bowel wall thickness (BWT ≥25% reduction); reduced colour doppler blood flow (inflammation, Limberg score ≤1) and normalisation of BWT (≤3mm). Patients with good quality baseline IUS and IUS-visible strictures were included for analysis. Results 77 patients underwent therapy randomisation. Of 63 patients with IUS-visible strictures 43 (68%) were in the intensive arm. Primary outcome was achieved by 32 (74%) patients in the intensive and 14 (70%) in the standard arms. Stricture resolution was seen in 1/5 non-responders and 18/45 responders. Median BWT reduced from 6.4mm (IQR 5.2-7.3mm) at baseline to 4.9mm (IQR 3-6mm) at 12 months (P<0.001). Clinical responders had significant reduction in median BWT from 6.0mm (IQR 4.5-7.1) at baseline to 4.3mm (IQR 3-5.7) at 12 months (P<0.001). There was no significant reduction in BWT at 4, 8 or 12 months in non-responders (P=0.26, P=0.29, P=0.26 respectively). BWT >3mm at 12 months occurred more often in non-responders than responders (P<0.05). Stricture resolution was seen in 13/36 in the intensive arm and 6/14 standard arm (P=0.75). The intensive arm had significant reduction in median BWT from 6.6mm (IQR 5.5-7.4mm) at baseline to 5.1mm (IQR 3-6.4mm) at 12 months (P<0.001). There was no significant reduction in BWT at 4, 8 or 12 months in the standard arm (P=0.75, P=0.42, P=0.09 respectively). There was no significant difference in BWT>3mm between trial arms at 12 months (P=1). Conclusion Stricture resolution and bowel wall thickness normalisation were demonstrated on intestinal ultrasound in stricturing Crohn’s disease patients treated with adalimumab therapy. Adalimumab therapy is associated with clinical improvement, and transmural improvement and healing, in patients with Crohn’s disease strictures.

P567 How can we predict the development of antibodies to infliximab in Crohn’s disease?

Abstract Background Anti-tumour necrosis factor-α (anti-TNF-α) therapy is an effective treatment for Crohn’s disease (CD). However, treatment failure is common. Our aim was to identify predictors of anti-TNF-α therapy failure. Methods Retrospective single-center study including anti-TNF-α naïve patients with CD, who started on intravenous infliximab, between January 2019 and December 2021. Biochemical parameters included erythrocyte sedimentation rate(ESR), c-reactive protein(CRP), faecal calprotectin, infliximab serum concentrations and antibodies to infliximab(ATI). Anti-TNF-α therapy failure was defined as ATI development at 6 or 12 months, absence of clinical response at 6 months, absence of clinical remission or objective response at 12 months. Clinical response was defined as reduction in Harvey-Bradshaw index(HBI) of≥3points comparing with initial value or HBI<5points if initial HBI≥7points and clinical remission as HBI≤4points. Objective response was assessed by endoscopic studies (improvement of mucosal inflammation and absence of deep ulcerations) or imaging (improvement in bowel wall thickness, inflammatory fat, mural blood flow and hyper-enhancement). Results Totally 53 CD patients were included, 49.1%treated with combination of anti-TNF-α and immunomodulatory therapy. Anti-TNF-α therapy failure occurred in 21 patients(39.6%). At 6 months, ATI development occurred in 6 patients(11.3%) and absence of clinical response in 9(17.0%). At 12 months, absence of clinical remission was seen in 13.6% of patients and absence of objective response in 27.0%. At 6 months, ATI development was significantly higher in patients with lower infliximab serum concentrations at week 14 (with ATI 5.9±3.2 vs without 14.3±7.7, p<0.001). Additionally, ATI development was significantly higher in patients with a higher initial value of ESR (with ATI median 35 vs without median 13, p=0.045). The infliximab serum concentrations at week 14 (AUC 0.828;p=0.009; sensitivity 0.833, specificity 0.404 for values≤11.6) and the initial value of ESR (AUC 0.754;p=0.045; sensitivity 0.833, specificity 0.468 for values≥15) had very good and good discriminative capacity, respectively, in predicting ATI development. No statistically significant differences were found in initial values of CRP and faecal calprotectin. The other definers of anti-TNF-α therapy failure were not associated with the combination with immunomodulatory therapy, infliximab serum concentrations at week 14 or initial values of biochemical parameters. Conclusion Infliximab serum concentration after induction is the most important factor in ATI development, influencing treatment response, regardless of the combination with immunomodulatory therapy. Higher initial value of ESR can also predict the development of ATI.

P330 Ultrasound remission after biologic induction predicts long-term endoscopic remission in Crohn’s disease

Abstract Background Intestinal ultrasound (IUS) is accurate and non-invasive to detect and monitor disease activity in Crohn’s disease (CD). The Bowel Ultrasound Score (BUSS= 0.75 × bowel wall thickness + 1.65 × presence (1) or absence (0) of bowel wall flow) demonstrated high accuracy in detecting therapy-related changes, and good correlation with the Simple Endoscopic Score for CD (SES-CD). The most accurate cutoff value for BUSS was 3.52 for endoscopic remission (SES-CD ≤ 2).This study aimed to prospectively evaluate ultrasound remission as a relevant treatment target. Methods Consecutive patients with active CD (SES-CD > 2) starting biologic treatments were included. Patients underwent colonoscopy and IUS at baseline and after 1 year of treatment. Clinical, biochemical and ultrasound assessments were additionaly performed at week 12. Primary outcome was to evaluate whether ultrasound remission at week 12 could predict endoscopic remission at week 54. Endoscopic remission was defined as SES-CD ≤ 2, ultrasound remission was defined by BUSS ≤ 3.52, clinical remission was defined by HBI (Harvey-Bradshaw Index) < 5, and biochemical remission was defined by normalization of C-reactive protein (< 5 mg/L) and fecal calprotectin (three different thresholds were assessed: < 250 µg/g, < 100 µg/g, < 50 µg/g). Results Ninety-three patients were included (8 under infliximab, 40 under adalimumab, 5 under vedolizumab and 40 under ustekinumab). Eighteen patients (19%) and 36 patients (39%) achieved endoscopic remission and ultrasound remission at week 54, respectively. CD patients with ultrasound remission at week 12 were more likely to achieve endoscopic remission (odds ratio [OR] 6.88 [2.14–22.04]; p = 0.001) and ultrasound remission (OR 4.26 [1.61–11.24]; p = 0.003) at week 54. Calprotectin value < 50 µg/g at week 12 predicted endoscopic remission at univariable (OR 3.14 [1.04–9.45]; p = 0.041), but not at multivariable analysis. No other clinical or biochemical variables at week 12 predicted endoscopic and/or ultrasound remission at week 54. Conclusion Ultrasound remission achieved at week 12 may predict long-term endoscopic remission and may be a strategic treatment target, both in clinical practice and in clinical trials.

P381 Ustekinumab trough levels are associated with sonographic transmural healing in Pediatric Inflammatory Bowel Disease

Abstract Background Transmural healing (TH) assessed by intestinal ultrasound (IUS) is associated with improved inflammatory bowel disease (IBD) outcomes. This study evaluates the relationship between ustekinumab trough levels (UTL) and sonographic TH in children with IBD treated with ustekinumab (UST). Methods Children (<18 years) with IBD treated with maintenance UST and undergoing IUS examination and serum UTL (Prometheus Labs, CA) at a single tertiary center between July 2020 and October 2022 were prospectively recruited. Children who underwent IUS and UTL on 2 events >6 months apart were included in a per-event analysis. Primary outcome was the comparison of UTL between children with and without TH, defined as bowel wall thickness (BWT) ≤3 mm and no hyperemia (BWH) on color Doppler, using the Mann-Whitney U test. Area under the receiver operating curve (AUROC) determined the optimal UTL cut-point to detect TH. Secondary outcome was the comparison of UTL for each IUS parameter. Descriptive statistics summarized the data as frequencies and percentages for categorical variables and median [interquartile range] for continuous variables. A p-value of significance was set to <0.05. Results Overall, 50 IUS exams on 129 bowel segments were performed in 44 children with IBD, 34:10 Crohn’s disease (CD):ulcerative colitis (UC)/IBD-U treated with UST, median [IQR] age 14.9[13.2-16.6] years, 22(50%) female, and disease duration 3.83[1.98-5.32] years (Table 1). 18(41%) children were treated with standard dose UST of 90mg every 8 weeks and had significantly lower UTL compared to 26(59%) treated with escalated dosing of 90 mg every 4 or 6 weeks (7.4[4.8-12.7] ug/ml vs. 11.6[6.1-19.3] ug/ml, p=0.002). Median time between UTL and IUS was 0 days [0-11.25]. Overall, 24(55%) children (18(53%) CD, 6(60%) UC/IBD-U) achieved TH. Higher UTL was associated with TH (13.1[6.1-17.5] ug/ml) compared to children without TH (5.7[4.2-13.9] ug/ml; p=0.010) (Figure 1A). Higher UTL was also associated with TH in children with CD (11.7[5.3-17.0] ug/ml) compared to children with CD without TH (5.5[4.2-11.0] ug/ml; p=0.013) (Figure 1B). Optimal UTL cut-point to detect TH was 11.4 ug/ml for all children (AUROC=0.647, sensitivity=62%, and specificity=69%) and children with CD (AUROC=0.661, sensitivity=59%, specificity=79%). Median UTL for all children was associated with lymphadenopathy (p=0.02) but no other individual IUS parameters (Table 2). Conclusion Higher maintenance UTL are associated with sonographic TH in children with IBD. Future prospective studies are needed to determine if targeting higher UTL levels during induction and maintenance UST therapy promotes TH.