The learning curve for using intestinal ultrasonography.

BACKGROUND AND AIMS: Intestinal ultrasonography (IUS) is challenging to learn. This prospective study examined how the accuracy of IUS increases with operator experience ("learning curve") and if prior abdominal ultrasound experience facilitates the learning process. METHODS: The study included two trainees with limited abdominal ultrasound experience (< 50 exams) and two with extensive experience (> 500 exams). Each trainee performed 99 examinations and reported four IUS findings. An expert sonographer repeated the exam, and concordance (k) between the expert and trainees was assessed in three consecutive testing periods of 33 exams each. RESULTS: A progressive improvement in concordance was observed for all IUS findings from Period 1 to Period 3, overall and for both groups of trainees, although those with experience in abdominal ultrasound had faster learning curves. The minimum number of examinations required to achieve concordance with the expert operator for detecting increased bowel wall thickness was 84 and detecting bowel dilatation was 79. However, a minimum of 97 examinations was necessary to achieve concordance for detecting intra-abdominal complications, considered an advanced IUS competence. CONCLUSION: Basic competence in IUS can be acquired with relatively few examinations, while advanced competence requires more extensive training, particularly for gastroenterologists without abdominal ultrasound experience.

Clinical trial: Combination allopurinol-thiopurine versus standard thiopurine in patients with IBD escalating to immunomodulators (the DECIDER study).

BACKGROUND: Thiopurines are established treatments for inflammatory bowel disease (IBD), yet concerns remain regarding their safety. AIM: To evaluate the use of thiopurine-allopurinol combination therapy compared to standard thiopurine therapy in IBD. METHODS: We performed a multicentre, randomised, placebo-controlled trial to compare the efficacy and safety of thiopurine-allopurinol versus thiopurine with placebo for adults commencing a thiopurine for IBD. Patients had active disease at baseline; dosing of therapy was based on a pre-specified regimen and subsequent metabolites. The primary outcome was the proportion of patients achieving a composite of symptomatic disease activity remission (Harvey Bradshaw Index <5 for Crohn's disease, Simple Clinical Colitis Activity Index <4 for ulcerative colitis) and a faecal calprotectin <150 µg/g after 26 weeks of treatment. RESULTS: The trial was terminated early due to slow recruitment. We randomised 102 participants (54 thiopurine-allopurinol, 48 thiopurine with placebo) with similar age (median 42 vs 48 years) and sex distribution (46% women per group). A higher proportion achieved the primary outcome in the thiopurine-allopurinol group (50% vs 35%, p = 0.14) and fewer participants stopped their allocated therapy due to adverse events (11% vs 29%, p = 0.02). Also, within the thiopurine-allopurinol group, thiopurine dose adjustments were less frequent (69% vs 92%, p = 0.03), a higher proportion achieved an early therapeutic 6-TGN level at week 6 (71% vs 53%, p = 0.19), and adverse events attributed to therapy were less frequent (15% vs 44%, p = 0.002). CONCLUSION: Thiopurine-allopurinol therapy is safe and mitigates thiopurine adverse effects, thus enhancing tolerability without compromising efficacy (ACTRN12613001347752).

Pharmacist-Driven Therapeutic Infliximab Monitoring at the Point of Care Using Rapidly Assessed Drug Levels in Patients with Inflammatory Bowel Disease.

BACKGROUND: Therapeutic monitoring of infliximab is limited by the time lag between drug-level measurement and dose adjustment, along with the cost of dose escalation. Strategies for dose reduction in stable patients on maintenance infliximab at supratherapeutic levels are uncertain. This study determined the feasibility of a pharmacist-driven strategy for immediate dose adjustment using a sliding scale at the point of care in stable patients with inflammatory bowel disease on maintenance therapy. METHODS: Adult patients with stable disease undergoing maintenance therapy with infliximab infusions, 5 mg/kg every 8 weeks, were prospectively studied. Trough drug levels were assessed by a rapid assay (and later by ELISA) at all infusions for up to 12 months with immediate but quantitatively small dose adjustment according to a sliding scale targeting a therapeutic range of 3-7 mcg/mL. Disease activity was assessed both clinically and biochemically. RESULTS: The rapid assay and ELISA detected similar infliximab levels, and the strategy added approximately 30 minutes to the duration of infusion events. Only 20% of 48 patients (77% with Crohn disease) had baseline trough infliximab concentrations within the therapeutic range. This value increased 3-fold after 24 and 48 weeks of interventions. One in 2 patients had baseline supratherapeutic levels, and most were brought into the therapeutic range without a discernible impact on disease activity by 1 dose adjustment, but 2 or 3 adjustments were generally needed for 29% of patients with subtherapeutic levels. Overall, drug costs were reduced by 4%. CONCLUSIONS: Immediate dose adjustment after infliximab rapid assay performed by a pharmacist using a sliding scale is a feasible strategy. Supratherapeutic infliximab levels can be safely and quickly brought into the therapeutic range using small dose adjustments without affecting disease activity, offsetting (at least partly) costs associated with dose escalation.

Nonspecific ileitis: Impact of histopathology and gastrointestinal ultrasound in achieving the diagnosis of Crohn's disease.

Background and Aim: Nonspecific ileitis is inflammation of the ileum without specific diagnostic features. A minority may go on to develop Crohn's disease, but optimal pathways of further investigation have not been established. This study aimed to identify a cohort of patients with nonspecific ileitis and to determine the value of ileal histology and gastrointestinal ultrasound in identifying/excluding Crohn's disease. Patients and Methods: In a retrospective analysis, all patients having nonspecific ileitis at colonoscopy from January 2010 to August 2021 were identified. Clinical associations with those subsequently diagnosed with Crohn's disease were examined with specific reference to ileal histology and gastrointestinal ultrasound. Results: Of 29 638 procedures, 147 patients (0.5%) had nonspecific ileitis. Crohn's disease was subsequently diagnosed in 8 patients (5.4%) at a median of 148 (range 27-603) days after colonoscopy. The presence of chronic inflammation on ileal biopsies was more common in those subsequently diagnosed with Crohn's disease (63% vs 20%; P = 0.0145). On gastrointestinal ultrasound, none of the 26 patients with normal bowel wall thickness (<3 mm) were subsequently diagnosed with Crohn's disease, and repeat ultrasound in 15 patients 1 year later showed no change. Of the nine patients with abnormal sonographic findings, three were diagnostic for Crohn's disease. Repeat ultrasound revealed Crohn's disease in two, while four had resolution of the abnormal findings. Conclusion: Although ileal histology was of limited value in identifying patients with nonspecific ileitis who were subsequently diagnosed with Crohn's disease, gastrointestinal ultrasound was highly informative. Prospective studies are needed to confirm the value of gastrointestinal ultrasound as a diagnostic and monitoring tool in this setting.

Early sonographic response to a new medical therapy is associated with future treatment response or failure in patients with inflammatory bowel disease.

OBJECTIVE: Gastrointestinal ultrasound (GIUS) accurately assesses inflammation and is responsive to changes in inflammatory bowel disease. This study aimed to determine the prognostic utility of sonographic response in the first 14 weeks of a newly-instituted therapy with therapeutic response at 46 weeks and to compare its performance with standard clinical assessment tools. METHODS: Patients with sonographic evidence of inflammation were assessed by GIUS, clinical activity, serum C-reactive protein and faecal calprotectin again 2, 6 and 14 weeks after commencing a new biologic or thiopurine. Treatment failure was defined as undergoing surgery, hospitalisation, escalation of dosage or introduction of new medication over 46-weeks' follow-up. Sonographic response was defined as a decrease in bowel wall thickness and improved vascularity. RESULTS: In 31 patients (median age 49 years, 74% Crohn's disease), sonographic response at 14 weeks [OR 19.3, 95% confidence interval (CI), 3.23-101.10; P = 0.0054] and faecal calprotectin (P = 0.018), but no clinical disease activity or C-reactive protein, were predictive of subsequent treatment response. Sonographic response alone was predictive at week 6 (P = 0.016), but not week 2. 16% reduction in bowel wall thickness at 6 weeks (area-under-the-receiver-operator-curve=0.86; P = 0.002; sensitivity 72%, specificity 90%), with similar performance for 10% at 14 weeks, was associated with treatment response. CONCLUSION: Sonographic response as early as 6 weeks after initiation of a new therapy may accurately predict treatment outcomes over 46 weeks and is superior to other markers used to monitor disease activity.

Accuracy of Gastrointestinal Ultrasound and Calprotectin in the Assessment of Inflammation and its Location in Patients with an Ileoanal Pouch.

BACKGROUND AND AIMS: In symptomatic patients with ileoanal pouches, pouchoscopy is needed for accurate diagnosis but is invasive. We aimed to assess the utility of non-invasive gastrointestinal ultrasound and faecal calprotectin in ileoanal pouch patients. METHODS: Patients with an ileoanal pouch were consecutively enrolled in this cross-sectional study from clinics in Victoria, Australia. The pouchitis disease activity index was used as a reference standard. Video-recorded pouchoscopies were reviewed by three gastroenterologists. Pouch, pre-pouch, and cuff biopsies were reviewed by a single pathologist. Ultrasound was performed by a single gastroenterologist transabdominally and transperineally. Faecal calprotectin was measured from morning stool samples. All examiners were blinded to patients' clinical history. RESULTS: A total of 44 participants had a pouchoscopy, of whom 43 had a faecal calprotectin test and 42 had an ultrasound; 17 had pouchitis, 15 had pre-pouch ileitis, and 16 had cuffitis. Pouch wall thickness of <3 mm was 88% sensitive in excluding pouchitis, and pouch wall thickness of ≥4 mm was 87% specific in diagnosing pouchitis. Transabdominal ultrasound had good utility [area under the curve: 0.78] in diagnosing moderate-severe pre-pouch ileitis. Transperineal ultrasound had good utility for the diagnosis of pouchitis [area under the curve: 0.79]. Faecal calprotectin differentiated inflammatory from non-inflammatory pouch disorders, such as irritable pouch syndrome, with an area under the curve of 0.90. Faecal calprotectin <100 µg/g ruled out inflammatory pouch disorders with a sensitivity of 94%. CONCLUSIONS: Faecal calprotectin and ultrasound are accurate and complementary tests to diagnose and localise inflammation of the ileoanal pouch. Prospective studies are needed to validate proposed sonographic indices and calprotectin levels.

Interrater reliability of the assessment of disease activity by gastrointestinal ultrasound in a prospective cohort of patients with inflammatory bowel disease.

OBJECTIVE: Gastrointestinal ultrasound is a radiological investigation for monitoring patients with inflammatory bowel disease. However, the reliability of the findings depends on the reproducibility of results between different operators. Thus, the study aim was to assess the interrater reliability of gastrointestinal ultrasound in individuals with inflammatory bowel disease between gastroenterologists with varying GIUS experience. . METHODS: Patients were prospectively recruited at the commencement of a new medical therapy for a baseline assessment, with a second assessment at the end of treatment induction (3 months). Consecutive, blinded ultrasounds were performed by two operators for every test. Gastrointestinal ultrasound examination included assessment of bowel wall thickness, vascularity, wall stratification assessment, mesenteric hyperechogenicity and lymphadenopathy. RESULTS: Forty-nine patients were recruited (Crohn's n = 27, ulcerative colitis n = 22) with 35 returning for a repeat assessment at 3 months. At baseline, the intraclass coefficient for bowel wall thickness was near perfect (0.882). By bowel segment, the closest correlation was in the terminal ileum and differences in bowel wall thickness were similar by disease subtype. All other ultrasound indices of disease activity demonstrated substantial to near-perfect agreement with Gwet's agreement coefficient: vascularity (0.681), wall stratification (0.685), mesenteric hyperechogenicity (0.841) and lymphadenopathy (0.633). Similar findings were seen at 3 months. CONCLUSION: There is substantial agreement between operators of varying experience in gastrointestinal ultrasound findings in patients with Crohn's disease or ulcerative colitis and this is repeatedly demonstrated over time. Thus, a well-trained operator should be sufficient to assess disease activity in patients with inflammatory bowel disease.

Effect of point-of-care gastrointestinal ultrasound on decision-making and management in inflammatory bowel disease.

BACKGROUND: Gastrointestinal ultrasound is increasingly used for point of care assessment of inflammatory bowel disease. AIMS: To explore the utility of gastrointestinal ultrasound as a point-of-care assessment tool from the perspectives of the clinician and patient. METHODS: A prospective, observational cohort study was designed utilising routine outpatient consultations. Adult patients with inflammatory bowel disease were allocated to receive gastrointestinal ultrasound or not at the discretion of their treating clinician. Patients completed self-reported session experience questionnaires at study entry, immediately after their consultation, and 4 and 16 weeks later. Clinicians reported disease activity status, therapeutic decisions and clinical management. RESULTS: Of 259 participants, mean age 40 (SD: 13) years, 54% male, 73 (28%) underwent ultrasound. Time since diagnosis was 9.2 (8.5) years (ultrasound) and 11.3 (9.2) years (no ultrasound). Immediately after ultrasound, patients who self-reported active disease reported better understanding of all aspects of their disease and disease symptoms were more confident in their ability to make informed decisions about managing their disease and had improved knowledge domain scores compared with the non-ultrasound group (all P < 0.05). Ultrasound had no influence over the patients' ability to manage their own healthcare but tended to be associated with transient improvement in medication adherence. After the ultrasound, the clinician's assessment of patient's disease activity changed in 22% (16/73) and management was altered in 56% (41/73) with anti-inflammatory therapy escalated in 33. About 47% (23/49) patients with Crohn's disease had their medication changed in the ultrasound group, compared to only 22% (25/112) in the nonultrasound group (P = 0.002). For patients with ulcerative colitis, medications were altered in 68% (15/22) compared to 26% (24/70) in the nonultrasound group (P = 0.005) When stratified for disease activity, medication change was more likely in those having ultrasound (P = 0.024). CONCLUSIONS: Point-of-care gastrointestinal ultrasound has the potential to enhance the clinical management of inflammatory bowel disease by contributing to clinician decision-making and education of patients regarding their disease.

Standardisation of intestinal ultrasound scoring in clinical trials for luminal Crohn's disease.

BACKGROUND: Intestinal ultrasound (IUS) is a valuable tool for assessment of Crohn's disease (CD). However, there is no widely accepted luminal disease activity index. AIMS: To identify appropriate IUS protocols, indices, items, and scoring methods for measurement of luminal CD activity and integration of IUS in CD clinical trials. METHODS: An expert international panel of adult and paediatric gastroenterologists (n = 15) and radiologists (n = 3) rated the appropriateness of 120 statements derived from literature review and expert opinion (scale of 1-9) using modified RAND/UCLA methodology. Median panel scores of 1 to ≤3.5, >3.5 to <6.5 and ≥6.5 to 9 were considered inappropriate, uncertain and appropriate ratings respectively. The statement list and survey results were discussed prior to voting. RESULTS: A total of 91 statements were rated appropriate with agreement after two rounds of voting. Items considered appropriate measures of disease activity were bowel wall thickness (BWT), vascularity, stratification and mesenteric inflammatory fat. There was uncertainty if any of the existing IUS disease activity indices were appropriate for use in CD clinical trials. Appropriate trial applications for IUS included patient recruitment qualification when diseased segments cannot be adequately assessed by ileocolonoscopy and screening for exclusionary complications. At outcome assessment, remission endpoints including BWT and vascularity, with or without mesenteric inflammatory fat, were considered appropriate. Components of an ideal IUS disease activity index were identified based upon panel discussions. CONCLUSIONS: The panel identified appropriate component items and applications of IUS for CD clinical trials. Empiric evidence, and development and validation of an IUS disease activity index are needed.

Early Assessment With Gastrointestinal Ultrasound in Patients Hospitalised for a Flare of Ulcerative Colitis and Predicting the Need for Salvage Therapy: A Pilot Study.

Approximately 30% of patients hospitalised with severe ulcerative colitis do not respond to corticosteroids, but the decision to introduce salvage therapy is delayed to at least the third day of treatment, according to the widely applied Oxford criteria to assess response. This pilot study aimed to determine if gastrointestinal ultrasound performed on admission can predict steroid-refractory disease. In 10 consecutive patients with severe ulcerative colitis, gastrointestinal ultrasound was performed within 24 h of admission. Six patients failed corticosteroids and required infliximab salvage therapy. Colonic bowel wall thickness was a median of 4.6 mm (range 4.2-5.6 mm) in those responding to steroids compared with 6.2 mm (6-7.9 mm) in those requiring salvage therapy (p = 0.009). Any colonic segment with a bowel wall thickness of >6 mm was associated with the need for salvage therapy (p = 0.033). Gastrointestinal ultrasound may provide an early indication of poor corticosteroid response and enable a timelier introduction of salvage therapy in patients with severe ulcerative colitis.

Effects of fiber intake on intestinal pH, transit, and predicted oral mesalamine delivery in patients with ulcerative colitis.

BACKGROUND AND AIM: Limited data are available on the effects of fermentable fiber in altering intestinal pH and transit to predict efficacy-based delivery profiles of pH-dependent mesalamine coatings in ulcerative colitis (UC). This study aimed to examine regional pH and transit after acute changes in fermentable fiber intake in quiescent UC patients and their effects on drug release systems. METHODS: In a randomized, double-blind study, 18 patients with quiescent UC and 10 healthy controls were supplied meals high (13 g) or low (≤ 2 g) in fermentable fiber and subsequently ingested a wireless pH-motility capsule. After a ≥ 3-day washout, they crossed over to the other diet. Measurements of intestinal pH and transit were used to predict drug release for the various pH-dependent coatings. RESULTS: Increasing fermentable fiber intake lowered overall (median 6.2 [6.1-6.7] vs low: 6.9 [range or interquartile range: 6.4-7.4]; P = 0.01) and distal pH (7.8 [7.3-8.1] vs 8.2 [8.0-8.5]; P = 0.04) in controls. In UC patients, only cecal pH was decreased (high: 5.1 [4.8-5.5] vs low: 5.5 [5.3-5.7]; P < 0.01). Colonic transit in the UC cohort varied widely after a low-fiber intake but tended to normalize after the high fermentable fiber intake. Hypothetical coating dissolution profiles were heterogeneous in UC patients, with a multi-matrix delayed release system having the highest likelihood of patients (20-40%) with incomplete dissolution, and predominant small intestinal dissolution predicted for Eudragit L (94% patients) and S (44-69%). CONCLUSIONS: Patients with quiescent UC have abnormalities in intestinal pH and transit in response to acute changes in fermentable fiber intake. These have potentially detrimental effects on predicted luminal release patterns of pH-dependent 5-aminosalicylic acid release systems.

Review article: determination of the therapeutic range for therapeutic drug monitoring of adalimumab and infliximab in patients with inflammatory bowel disease.

BACKGROUND: Clinical application of therapeutic drug monitoring (TDM) to optimise anti-TNF therapies in patients with IBD depends upon target ranges. AIMS: To review methodology used to determine therapeutic ranges and critically compare and contrast its application to infliximab and adalimumab. METHODS: A systematic review was performed, and relevant literature was summarised and critically examined. RESULTS: Upper limits of the therapeutic range are determined by toxicity, a plateau response and cost. Lower limits are determined by optimal concentration on the target of action in vitro and/or in vivo, or by correlation of drug levels with clinical efficacy using area-under-receiver-operator-curve (AUROC) analysis. In 43 studies, there were huge variations in time at which infliximab and adalimumab levels were measured, the end-points used (clinical remission to mucosal healing), the clinical setting (active disease vs maintenance phase) and the reason for TDM (proactive vs reactive). In the maintenance phase for infliximab, lower trough limits 2.8-5.7 µg/mL are reported depending upon end-points used, with consistent AUROC 0.68-0.77. Adalimumab TDM targets are even less consistent with a lower limit 5.9-11.8 µg/mL (AUROC 0.66-0.83) in some studies, but no cut-off can be identified that is significantly associated with outcome in others, related to inherent pharmacokinetic and pharmacodynamic differences, and heterogeneity of study design. CONCLUSIONS: Evidence for exposure-response relationship is stronger for infliximab than adalimumab. Due to heterogeneity in settings for drug level measurements, therapeutic ranges vary. These factors need to be taken into account when interpreting the evidence and extending this to therapeutic strategies for IBD patients.

Systematic Review: Clinical Utility of Gastrointestinal Ultrasound in the Diagnosis, Assessment and Management of Patients With Ulcerative Colitis.

BACKGROUND AND AIMS: Gastrointestinal ultrasound is useful in the assessment of patients with Crohn's disease, but its application in ulcerative colitis [UC] is less well established. Here we systematically review the role of gastrointestinal ultrasound in patients with UC. METHODS: Searches of the PUBMED and EMBASE databases were performed with the following search strategy: [ultrasound OR sonography] AND [intestinal OR bowel] AND [ulcerative colitis OR inflammatory bowel disease]. The final search was performed in August 2019. RESULTS: Of 6769 studies identified in the search with a further two studies found from other sources, 50 studies met the inclusion criteria. Increased bowel wall thickness and detection of increased blood flow by colour Doppler were the most often applied criteria for defining disease activity and distribution. When compared with other reference investigations, gastrointestinal ultrasound accurately determined disease extent, severity and response to medical therapy. While further information can be obtained from haemodynamic measurements of the abdominal vessels and contrast-enhanced ultrasound, their clinical value was uncertain. Likewise, hydrocolonic sonography has few advantages over standard gastrointestinal ultrasound examination. Of several scoring systems proposed, there is disparity between the measures and a general lack of validation. There has been limited application of gastrointestinal ultrasound in acute severe ulcerative colitis with toxic megacolon, and, while performing well in children, normal limits differ from those in adults. CONCLUSION: Current evidence indicates that gastrointestinal ultrasound has utility in the non-invasive assessment of patients with UC. Continued advances in technology with better image resolution, validation of scoring systems and application at the point of care by gastroenterologists are likely to contribute to increased use of gastrointestinal ultrasound in routine clinical practice.

Low-dose thiopurine with allopurinol co-therapy overcomes thiopurine intolerance and allows thiopurine continuation in inflammatory bowel disease.

AIMS: To assess the utility and tolerability of thiopurine-allopurinol co-therapy in inflammatory bowel disease (IBD) patients with intolerance to thiopurine monotherapy. METHODS: A retrospective observational study assessed cases of thiopurine intolerance then switched to thiopurine allopurinol co-therapy between 2011 and 2015 at two centres. Indications for switch, dosing and subsequent clinical outcomes (including thiopurine persistence) were recorded. RESULTS: Of 767 patients on thiopurines for IBD, 89 (12%) were switched to co-therapy for intolerance. 64/89 (72%) had Crohn's disease, 38 (43%) were males, median age at switch was 40y (range 17-78), median IBD duration 6y (0-29). Median follow-up was 1.9y (0-5). Reasons for switching to co-therapy included fatigue (37%), hepatotoxicity (23%), nausea (23%), arthralgia (10%), headache (12%) and hypersensitivity reaction (4%). Overall, 66 (74%) patients remained on co-therapy until most recent review and achieved a clinical response. High rates of overcoming intolerance (62-100%) occurred with co-therapy for all reasons above, although fatigue was less amenable to switching than non-fatigue indications (62% vs 91%, p = <0.001). Of 34 patients not escalated to biologics with endoscopic data, 15 were in remission (44%) at most recent review. CONCLUSION: Low-dose thiopurine combined with allopurinol appears safe and effective in overcoming intolerances to thiopurine monotherapy in many cases.

Gastrointestinal ultrasound in inflammatory bowel disease: an underused resource with potential paradigm-changing application.

Evolution of treatment targets in IBD has increased the need for objective monitoring of disease activity to guide therapeutic strategy. Although mucosal healing is the current target of therapy in IBD, endoscopy is invasive, expensive and unappealing to patients. GI ultrasound (GIUS) represents a non-invasive modality to assess disease activity in IBD. It is accurate, cost-effective and reproducible. GIUS can be performed at the point of care without specific patient preparation so as to facilitate clinical decision-making. As compared with ileocolonoscopy and other imaging modalities (CT and MRI), GIUS is accurate in diagnosing IBD, detecting complications of disease including fistulae, strictures and abscesses, monitoring disease activity and detecting postoperative disease recurrence. International groups increasingly recognise GIUS as a valuable tool with paradigm-changing application in the management of IBD; however, uptake outside parts of continental Europe has been slow and GIUS is underused in many countries. The aim of this review is to present a pragmatic guide to the positioning of GIUS in IBD clinical practice, providing evidence for use, algorithms for integration into practice, training pathways and a strategic implementation framework.

Failure of gastroenterologists to apply intestinal ultrasound in inflammatory bowel disease in the Asia-Pacific: a need for action.

Intestinal ultrasound (IUS) is a cheap, noninvasive, risk-free procedure that is significantly underutilized in the diagnosis and management of patients with inflammatory bowel disease (IBD) in the Asia-Pacific region. More cost-effective methods of monitoring disease activity are required in light of the increasing global burden of IBD (especially in Asia), the advent of personalized medicine, and the rising cost of healthcare. IUS is a prime example of a technique that meets these needs. Its common clinical applications include assessing the activity and complications of IBD. In continental Europe, countries such as Germany and Italy use this imaging tool as the standard of care and have integrated it into management protocols. There are formal training programs in these countries to train gastroenterologists in IUS, and it is used in an outpatient setting during patient consultations. Barriers to its use in the Asia-Pacific region include lack of experience and research data, and there are few established centers with active training programs. These concerns can be addressed by investing more in IUS service provision and by increasing allocation of resources toward local research and training. Increased uptake of IUS will ultimately benefit patients with IBD.

Accuracy and cost of diagnostic strategies for patients with suspected Crohn's disease.

OBJECTIVE: To evaluate accuracy and cost of non-invasive diagnostic strategies including magnetic resonance imaging, intestinal ultrasonography, ileocolonoscopy and video-capsule endoscopy in suspected Crohn's disease. METHODS: A decision-analytic model was used to assess the costs in low (25%), intermediate (50%) or high (75%) pre-test probability of Crohn's disease. Based on the published accuracy of diagnostic modalities and Bayes' rule, we calculated post-test probability of Crohn's disease using different strategies, starting from ileocolonoscopy, ultrasonography or magnetic resonance. Each strategy was considered successful when post-test probability was >95% or <5%. RESULTS: With low pre-test probability, only ileocolonoscopy as the first investigation could exclude or confirm Crohn's disease while a normal ultrasonography may exclude Crohn's disease. With high pre-test probability, ileocolonoscopy or ultrasonography as the first test may confirm Crohn's disease, but at least 3 negative tests are required to exclude Crohn's disease. The cost to diagnose one patient was cheapest utilising an ultrasonography-based strategy both in low (ultrasonography €1076; ileocolonoscopy €2005; magnetic resonance €4515) and high pre-test probability of Crohn's disease (ultrasonography €321; ileocolonoscopy €712; magnetic resonance €1412). CONCLUSION: The accuracy and cost of these strategies depend on pre-test probability of Crohn's disease and vary according to the first test used. Ileocolonoscopy plus ultrasonography is the most accurate and less expensive initial diagnostic strategy.