Clinical relevance of transabdominal ultrasonography and magnetic resonance imaging in patients with inflammatory bowel disease of the terminal ileum and large bowel

Bowel Ultrasonography in Inflammatory Bowel Disease

BACKGROUND

The diagnosis of inflammatory bowel disease (IBD) is based on a combination of endoscopic, clinical and biochemical investigations as well as cross-sectional imaging. The applications of cross-sectional imaging in IBD are manifold. Ultrasonography has emerged as an important imaging modality in the diagnosis of Crohn's disease (CD) as well as for monitoring disease progression and in the therapeutic response to CD and ulcerative colitis (UC). Key Messages: Ultrasonography is non-invasive, radiation free, cheap, easy to use and well tolerated and accepted by patients. Bowel ultrasonography can be used for the primary diagnosis of CD as it has a similar sensitivity and specificity like that of MRI and CT, particularly in the case of CD. Ultrasonography can also be used to monitor treatment response to therapy and to detect disease recurrence of CD as well as UC. In CD, ultrasonography can also be used to detect complications such as strictures as well as extramural complications, including abscesses and fistulas. Contrast-enhanced ultrasonography is a useful tool that might be helpful to detect certain indications in CD, in particular the differentiation between abscesses and inflammation.

CONCLUSION

A variety of advantages of bowel ultrasonography over other imaging modalities suggest the more frequent use of this method to manage IBD patients in daily practice. Bowel ultrasonography should be a standard tool in IBD centers.

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.

Ultrasonography of the colon in pediatric ulcerative colitis: a prospective, blind, comparative study with colonoscopy

OBJECTIVES

To evaluate the usefulness of colonic ultrasonography (US) in assessing the extent and activity of disease in pediatric ulcerative colitis (UC) and to compare US findings with clinical and endoscopic features.

STUDY DESIGN

Consecutive pediatric patients (n = 60) with a diagnosis of UC and suspected disease flare-up were prospectively enrolled; of these, 50 patients were eligible for the study. All underwent clinical evaluation, bowel US with color Doppler examination and colonoscopy. Blind US was performed the day before endoscopy in all patients. The US assessed variables were bowel wall thickness >3 mm, bowel wall stratification, vascularity, presence of haustra coli, and enlarged mesenteric lymph nodes.

RESULTS

The endoscopic extent of disease was independently confirmed in 47 patients by US that yielded a 90% concordance with endoscopy (95% CI 0.82-0.96). Multiple regression analysis showed that US measurements with an independent predictive value of severity at endoscopy were increased bowel wall thickness (P < .0008), increased vascularity (P < .002), loss of haustra (P = .031), and loss of stratification of the bowel wall (P = .021). Each variable was assigned a value of 1 if present. The US score strongly correlated with clinical (r = 0.94) and endoscopic activity (r = 0.90) of disease (P < .0001).

CONCLUSIONS

Colonic US is a useful first line noninvasive tool to assess the extent and activity of disease in children with UC and to estimate the severity of a flare-up, prior to further invasive tests.

Radiographical evaluation of ulcerative colitis

Radiographical modalities have become important diagnostic tools in cases of ulcerative colitis (UC). Imaging can be used non-invasively to determine the extent of involvement, severity of disease and to detect disease-related complications and extra-intestinal inflammatory bowel disease (IBD) manifestations. While abdominal X-rays and barium enemas still retain their relevance in specific clinical settings, the use of computed tomography enterography (CTE) or magnetic resonance enterography (MRE) are now used as first-line investigations to exclude active small bowel disease in IBD patients and can be utilized to detect active colonic inflammation. Additionally, CT colonography and MR colonography are emerging techniques with potential applications in UC. Ultrasonography, leukocyte scintigraphy and positron emission tomography are novel abdominal imaging modalities currently being explored for IBD interrogations. This plethora of radiological imaging options has become a vital component of UC assessments.

[Diagnostic options. Indications and validity]

BACKGROUND

A variety of diagnostic methods provide the necessary rational basis for diagnosis, assessment of disease activity and exclusion of possible complications for patients with inflammatory bowel disease (IBD).

AIM

Currently, a wide range of diagnostic methods is available and easily accessible. The clinical use of all these different methods is inherently possible. As there is no reference test for either diagnosis or monitoring of IBD, diagnostic techniques must be selected, applied and interpreted in an appropriate clinical context. The objective is to evaluate the clinical, laboratory and imaging techniques including ultrasound and endoscopy in different clinical situations.

RESULTS

In addition to clinical parameters, fecal calprotectin and abdominal ultrasound are helpful tools to assess the inflammatory activity. In patients with high inflammatory activity, a routine endoscopy is not beneficial. At best, endoscopy can be performed to document the extent of mucosal inflammation before initiating an intensified immunosuppressive therapy. Knowledge and experience in the management and treatment of IBD complications are critical in providing a rational use of specific diagnostic methods.

CONCLUSION

As a basic principle, the critical evaluation of diagnostic methods in patients with IBD is of great importance. Specific clinical situations require specific diagnostic techniques. Every diagnostic method performed should have a purpose.

Comparison between 1.5 and 3.0 Tesla magnetic resonance enterography for the assessment of disease activity and complications in ileo-colonic Crohn's disease

BACKGROUND

Magnetic resonance imaging (MRI) can assess disease activity and severity in Crohn's disease (CD). Three-Tesla magnetic resonance (3T) increases signal-to-noise ratio (SNR) and reduces time of image acquisition (IAT). Whether 3T increases the accuracy of MRI in CD compared to 1.5T is unknown.

AIM

We aimed to compare prospectively the accuracy of 3 and 1.5T in ileo-colonic CD patients.

METHODS

Twenty-six patients with ileo-colonic CD underwent 1.5 and 3T MR enterography at the same time. Ileocolonoscopy was the reference standard for luminal disease. Sensitivity, specificity and accuracy of MRI in evaluating six signs of active and complicated disease (localization, thickening, enhancement, strictures, entero-enteric fistulas, and ulcers) were calculated for both techniques.

RESULTS

Three-Tesla resulted as sensitive, specific, and accurate as 1.5T in detecting disease location (accuracy 0.93 vs. 0.86), bowel wall thickening and enhancement (accuracy 0.92 vs. 0.80 for both parameters), strictures (accuracy 0.90 vs. 0.80) and entero-enteric fistulas (accuracy 0.92 vs. 0.92). 3T was superior to 1.5T in detecting ulcers (0.76 vs. 0.42, P < 0.05). SNR resulted higher in 3T, and IAT resulted shorter than 1.5.

CONCLUSIONS

We found that 3T is equally accurate as 1.5T in evaluating ileo-colonic CD. Because of superiority in detecting mucosal ulcers, 3T should be preferred in patients with ileo-colonic CD.

Diagnostic accuracy of magnetic resonance colonography for the evaluation of disease activity and severity in ulcerative colitis: a prospective study

OBJECTIVE

The aim of this study was to determine the diagnostic accuracy of magnetic resonance colonography (MRC) for the evaluation of disease activity and severity in patients with ulcerative colitis (UC) using endoscopy as the reference standard.

METHODS

Fifty patients with UC underwent colonoscopy and MRC for the evaluation of disease activity. All patients were prospectively and consecutively included. Endoscopic activity was evaluated globally and on a segment basis using the modified Baron score (MBS), and also classified as absent, mild to moderate (inflammation without ulcers) or severe (presence of ulceration). MRC parameters evaluated in each segment were: wall thickness, pre- and post-contrast wall signal intensity, relative contrast enhancement (RCE), mural oedema, ulcers, enlarged lymph nodes and the comb sign.

RESULTS

Independent predictors for endoscopic activity on a segment basis were RCE (p=0.006), presence of oedema (p=0.003), enlarged lymph nodes (p<0.001) and the comb sign (p<0.001). A segmental simplified MRC index (MRC-S) ≥ 1 detected endoscopic inflammation with high diagnostic accuracy (sensitivity 87%, specificity 88%, area under the curve (AUC) 0.95; p<0.001). MRC-S index ≥ 2 detected severe lesions with high sensitivity (83%) and specificity (82%) with an AUC of 0.91 (p<0.001). The MRC-S index strongly correlated with the MBS (r=0.81, p<0.001) and with the subjective assessment of the radiologists for the evaluation of disease severity (r=0.77, p<0.001).

CONCLUSIONS

MRC has a high accuracy for the diagnosis of disease activity and severity in UC.

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

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

Imaging indexes of activity and severity for Crohn's disease: current status and future trends

BACKGROUND

Cross-sectional imaging techniques, including ultrasonography (US), computed tomography (CT), and magnetic resonance imaging (MRI) are increasingly used for evaluation of Crohn's disease (CD).

AIM

To review the accuracy of cross-sectional imaging indexes for measurement of disease activity and severity in patients with CD, and to evaluate its applicability on daily clinical practice and research.

METHODS

Relevant publications were identified by literature search, and selected based on predefined quality parameters, including a sample size and reference standard. Nineteen publications were chosen.

RESULTS

The US-based indexes of activity showed high correlation with reference standard indexes. There is a good or very good agreement between the MR-based indexes and the reference standard when the comparison is limited to small segments of intestine. Significant discrepancies have been found between indexes that evaluate the colon. Only one CT-based index was included. The main strengths and weaknesses of the indexes, according to its design, are discussed.

CONCLUSION

Standardization of image acquisition protocols and patient preparation should be procured, especially for MRI. In daily practice, a simple, semi-quantitative index providing relevant information on disease activity and severity is preferable. For research purposes, a precise and reproducible index should be mandatory.

Resistance index in mural arteries of thickened bowel wall: predictive value for Crohn disease activity assessment in pediatric patients

OBJECTIVE

To define reliable Doppler parameters in mural arteries of affected bowel loops for quantitative assessment of Crohn disease (CD) activity in pediatric population and compare Doppler parameters with Pediatric Crohn Disease Activity Index (PCDAI).

PATIENTS AND METHODS

Thirty-four pediatric patients (7 with inactive, 27 with active disease of different severity; 13 male and 21 female; mean age 13; range 7-18) with CD were prospectively evaluated by Doppler ultrasound (DUS) of affected bowel segments. Using semiquantitative color and power Doppler assessment of vascularization of thickened bowel wall and mesentery, patients were divided in four grades. Spectral measurements (peak systolic velocity (PSV), end diastolic velocity (EDV), resistance index (RI)) of mural arteries were compared with PCDAI.

RESULTS

There was a significant difference in distribution of semiquantitative color values between inactive and active group. PSV and EDV values showed no significant difference between inactive and active group, while mean RI was significantly higher in the inactive group. RI was also significantly negatively correlated with PCDAI.

CONCLUSION

Intensity of color and power Doppler signals and RI measurement of mural arteries in thickened bowel wall is linked to CD activity and therefore might be of use in pediatric patients.

Contrast-enhanced ultrasonography (CEUS) vs. MRI of the small bowel in the evaluation of Crohn's disease activity

PURPOSE

The presence of disease activity in Crohn's disease (CD) is one of the main parameters used to establish whether optimal therapy should be drug therapy or surgery. However, a major problem in monitoring CD is the common mismatch between the patient's symptoms and imaging objective signs of disease activity. Bowel ultrasonography (US) has emerged as a low-cost, noninvasive technique in the diagnosis and follow-up of patients with CD. Accordingly, the use of contrast-enhanced US (CEUS) has made possible an evaluation of the vascular enhancement pattern, similar to the use of magnetic resonance imaging (MRI). The aim of our study was to evaluate the role of CEUS in comparison with small-bowel MRI for assessing Crohn's disease activity.

MATERIALS AND METHODS

We prospectively enrolled 30 consecutive patients with known CD. Clinical and laboratory data were compared with imaging findings obtained from MRI and CEUS of the small bowel. MRI was performed with a 1.5-T system using phased-array coils and biphasic orally administered contrast agent prior to and after gadolinium chelate administration. We performed US with a 7.5-MHz linear-array probe and a second-generation contrast agent. The parameters analysed in both techniques were the following: lesion length, wall thickness, layered wall appearance, comb sign, fibroadipose proliferation, presence of enlarged lymph nodes and stenosis. We classified parietal enhancement curves into two types in relation to the contrast pattern obtained with the time-intensity curves at MRI and CEUS: (1) quick washin, quick washout, (2) slow washin, plateau with a slow washout.

RESULTS

Comparison between Crohn's disease activity index (CDAI) and MRI showed a low correlation, with an rho=0.398; correlation between CDAI-laboratory data and CEUS activity was low, with rho=0.354; correlation between MRI activity and CEUS activity was good, with rho = 0.791; high correlation was found between CEUS and MRI of the small bowel when assessing wall-thickness, lymph nodes and comb sign; good correlation was fund when assessing layered wall appearance, disease extension and fibroadipose proliferation. At MRI, time-intensity curves for 12/30 patients were active, compared with for 14/30 patients at CEUS; therefore there was a poor correlation between curve on CEUS and curve on MRI (r=0.167; p=0.36).

CONCLUSIONS

The use of CEUS can be recommended if there is a discrepancy between MRI and clinical/laboratory parameters. MRI of the small bowel remains the most accurate method for evaluating disease activity.

Ultrasonographic assessment of colonic wall in moderate-severe ulcerative colitis: comparison with endoscopic findings

BACKGROUND

Bowel ultrasound has been shown to be a useful tool to evaluate patients with inflammatory bowel disease, especially Crohn's disease. However, such data are still scarce in ulcerative colitis patients.

AIMS

To establish the value of bowel ultrasound in moderate to severe ulcerative colitis patients, and compare these data with endoscopic findings.

PATIENTS AND METHODS

Endoscopic, ultrasound and C-reactive protein data from 51 patients with moderate to severe ulcerative colitis observed during a 3-year period were retrospectively obtained and analysed.

RESULTS

All patients displayed pathological thickness (>4 mm) of the colon wall. This value strongly correlated with C-reactive protein values (p=0.0001) and the endoscopic score (p<0.0001). Also, a strong correlation (p<0.0001) was found between CRP values and endoscopic score.

CONCLUSIONS

Bowel ultrasound, in expert hands, may represent a useful adjunctive (or first line) tool for the evaluation of patients with moderate to severe ulcerative colitis.

Relative efficacy of different MRI signs in diagnosing active Crohn's disease, compared against a histological gold standard

INTRODUCTION

There has been growing interest in the use of MRI in assessing Crohn's disease because of its lack of ionising radiation. Many MRI signs have been described in the literature, but their relative utility is unknown.

METHODS

The MRIs of the bowel performed at 1.5 Tesla were blindly reviewed on 26 patients with recent histology (surgery and/or colonoscopy and their associated reports) according to a dedicated pro forma. Each patient's bowel was divided into nine segments. Each segment was assessed as to the presence or absence of 15 MRI signs described in the literature: abnormal gadolinium enhancement (both subjective and objective), wall oedema, fat oedema, fat proliferation, nodal enlargement, free fluid, wall nodularity, serosal blurring, mural thickening >4 mm, stricture, multi-segmental disease, fistula, abscess and layered contrast enhancement. The results were compared against a histological gold standard with a six-point scale of disease severity.

RESULTS AND CONCLUSIONS

MRI correctly identified all 15 patients with at least established mucosal disease, and three of eight with only mild mucosal disease. Combining these results, a positive MRI correlated highly with at least early mucosal disease (positive predictive value 95%), while the presence of established mucosal disease was unlikely if MRI was negative (negative predictive value 100%). The MRI signs found to be the most sensitive for detecting active Crohn's disease were those related to the bowel wall, namely, wall thickening, nodularity, contrast enhancement and oedema. The most specific signs were the presence of multi-segmental disease, layered contrast enhancement and complications (fistula and abscess).

Diagnostics in inflammatory bowel disease: Ultrasound

Diagnosis of chronic inflammatory bowel diseases (IBD) is based on a combination of clinical symptoms, laboratory tests and imaging data. Imaging of the morphological characteristics of IBD includes the assessment of mucosal alterations, transmural involvement and extraintestinal manifestations. No single imaging technique serves as a diagnostic gold standard to encompass all disease manifestations. Ultrasound, computed tomography (CT) or magnetic resonance imaging (MRI) allow cross-sectional imaging of the transmural alterations and extraintestinal manifestations. While in the USA the technique of choice is CT, in Europe the focus is more on MRI and ultrasound (US). Most patients with chronic IBD are diagnosed at a young age. After baseline diagnosis many of these young patients have to undergo repetitive imaging procedures during the variable clinical course of the disease, characterized by alternate periods of remission and active disease, and in monitoring the response to treatment. US has the advantage of being noninvasive, less costly, and easily repeatable, and thus can be very useful in following up patients with IBD. In addition, rising concern about radiation exposure in young adults indicates the demand for radiation-sparing techniques like US and MRI. This article focuses on the current clinical practice of US in IBD, describing the current technologies used in transabdominal intestinal US and the characteristic sonographic findings in Crohn´s disease and ulcerative colitis.

Systematic review: the use of ultrasonography, computed tomography and magnetic resonance imaging for the diagnosis, assessment of activity and abdominal complications of Crohn's disease

BACKGROUND

Cross-sectional imaging techniques, including ultrasonography (US), computed tomography (CT) and magnetic resonance imaging (MRI), are increasingly used for evaluation of Crohn's disease (CD). Aim  To perform an assessment of the diagnostic accuracy of cross-sectional imaging techniques for diagnosis of CD, evaluation of disease extension and activity and diagnosis of complications, and to provide recommendations for their optimal use.

METHODS

Relevant publications were identified by literature search and selected based on predefined quality parameters, including a prospective design, sample size and reference standard. A total of 68 publications were chosen.

RESULTS

Ultrasonography is an accurate technique for diagnosis of suspected CD and for evaluation of disease activity (sensitivity 0.84, specificity 0.92), is widely available and non-invasive, but its accuracy is lower for disease proximal to the terminal ileum. MRI has a high diagnostic accuracy for the diagnosis of suspected CD and for evaluation of disease extension and activity (sensitivity 0.93, specificity 0.90), and is less dependent on the examiner and disease location compared with US. CT has a similar accuracy to MRI for assessment of disease extension and activity. The three techniques have a high accuracy for identification of fistulas, abscesses and stenosis (sensitivities and specificities >0.80), although US has false positive results for abscesses. As a result of the lack of radiation, US or MRI should be preferred over CT, particularly in young patients.

CONCLUSIONS

Cross-sectional imaging techniques have a high accuracy for evaluation of suspected and established CD, reliably measure disease severity and complications; they may offer the possibility to monitor disease progression.

Comparison between a clinical activity index (Harvey-Bradshaw-Index), laboratory inflammation markers and quantitative assessment of bowel wall vascularization by contrast-enhanced ultrasound in Crohn's disease

PURPOSE

Due to its character as a remitting inflammatory disease, patients suffering from Crohn's disease (CD) often undergo several imaging studies subjecting the mostly young patients to ionizing. Contrast enhanced ultrasound for capillary microvascular assessment might be a new diagnostic tool for identifying the activity of inflammation by ultrasound techniques.

MATERIALS AND METHODS

We prospectively evaluated 45 patients with proven Crohn's disease performing contrast enhanced ultrasound (CEUS) and laboratory assessment including C-reactive protein (CRP), leucocytes and hematocrit as well as calculating the Harvey-Bradshaw Index (HBI). Thereafter, we applied the quantification software Qontrast(®) to obtain contrast-enhanced sonographic perfusion maps.

RESULTS

Analysis of the 41 finally included patients revealed a correlation of CRP to HBI and TTP[s], respectively. Moreover, an association was found for HBI and TTP[s] and for HBI and TTP[s]/Peak [%]. Analysis of 34 patients with a Peak [%] ≥ 25 showed a close association of HBI and CRP. Besides, in these patients CRP correlated to TTP[s] and to TTP[s]/Peak [%]. We found a strong negative correlation between HBI and TTP[s] (r = -0.645, p<0.01), thus, the higher the clinical activity the shorter the time-to-peak.

CONCLUSION

Quantitative evaluation with CEUS, particularly the calculation of TTP[s] in patients with a Peak [%] ≥ 25, provides a simple method to assess the inflammatory activity in CD.

Possible role of early transabdominal ultrasound in patients undergoing cytapheresis for active ulcerative colitis

BACKGROUND

Cytaphresis (CAP) is an effective modality in the treatment of active ulcerative colitis (UC), but the time lag before a notable clinical response on scheduled therapy frequently causes a significant delay in the modification of treatment. We previously reported that the clinical response after CAP was predicted by early application of transabdominal ultrasound (TAUS), but the predictability of long-term outcome after CAP still remains uncertain. METHODS PATIENTS: Twenty-six patients with active UC who received CAP were followed for 1 year. In addition to CAP they received pharmaceutical regimens, such as corticosteroid, 5-aminosalicylic acid, and immunomodulator, as indicated clinically. The mean UC-DAI score was 9.7 before CAP, and 3.2 at 1 year after CAP. Prognostic factor: Total colonic wall thickness was measured by TAUS at 2 to 3 weeks after the initiation of the treatment, and decrement from baseline was calculated. Early ultrasonographic response (EUR) was defined as a decrement statistically. UC-DAI score of 2 or less at 1 year was defined as sustained clinical remission. Score of 6 or more was defined as clinical relapse.

RESULTS

EUR was defined as a decrement in wall thickness by at least 2.5 mm from the baseline. EUR was noted in 11 patients, and the remaining 15 did not attain EUR.

OUTCOME MEASURES

In the UC-DAI score measured at 1 year after initiation of treatment 90.9% of patients with EUR, whereas 40.0% with non-EUR (p<0.05) showed sustained clinical remission. Regarding relapse, within 1 year 9.1% of patients with EUR relapsed whereas 46.7% with non-EUR (p<0.05) relapsed.

CONCLUSION

Early application of TAUS may predict the long-term clinical outcome after CAP in patients with active UC.

Diagnostic value of ultrasonography for detection of intestinal diseases

When ultrasonography was initially introduced into clinical practice, its use for detection of intestinal diseases was greatly restricted due to the problem that ultrasound imaging is greatly affected by gas. However, with the development of ultrasound technology, ultrasonography has been applied widely to the detection of intestinal diseases in recent years. In this article, we will review the application value of different ultrasound methods in the diagnosis of intestinal eminence diseases, mesenteric ischemic diseases, intestinal acute abdomen, and intestinal motility disorders. Furthermore, we will discuss the disadvantages of ultrasonography in diagnosis of intestinal diseases to provide a reference for clinicians.

Ultrasound and inflammatory bowel disease

Transabdominal bowel sonography is a fast, efficient, and cheap way of examining the intestines. It is also virtually hazard-free and well accepted by patients. During the last 20 years, it has been established as a procedure for detecting bowel disease early in the diagnostic workup. Although rather unspecific, the method is sensitive for detection of bowel disease and can be applied to find the extent and location of inflammatory bowel disease. In patients with known ulcerative colitis and Crohn disease, it can also be used for follow-up because it is easily repeatable and radiation-free. Because it can be applied to find both intraluminal and peri-intestinal pathological features, it is a particularly valuable tool for the detection of complications of Crohn disease as stenosis, fistulas, and abscesses. Neither B-mode nor Doppler techniques have been proven obviously useful in categorizing disease activity, but new techniques using intravenous contrast might come closer to solving this question. Finally, recent longitudinal studies using transabdominal bowel sonography show that it can also give important prognostic information and be used for monitoring the effect of therapy.

Are colonoscopy and bowel ultrasound useful for assessing response to short-term therapy and predicting disease outcome of moderate-to-severe forms of ulcerative colitis?: a prospective study

OBJECTIVES

Mucosal healing has been proposed as an important sign of the efficacy of medical treatment of inflammatory bowel disease; however, direct evidence in ulcerative colitis (UC) is scarce. We evaluated the usefulness of colonoscopy and bowel ultrasound (US) as indexes of response to short-term therapy and as predictors of subsequent outcome in UC.

METHODS

A total of 83 patients with moderate-to-severe UC were recruited; endoscopic and US severity was graded 0-3 at entry according to validated scores. Of the recruited patients, 74, who were clinically responsive to steroids, were followed up with repeated colonoscopy and bowel US at 3, 9, and 15 months from recruitment. Concordance between clinical, endoscopic, and US scores at various visits was determined by kappa statistics. Multiple unconditional logistic regression models were used to assess the predictivity of clinical, endoscopic, and US scores measured at 3 and 9 months on the development of endoscopic UC relapse within 15 months.

RESULTS

A variable concordance was found over time between endoscopic and clinical score (weighted kappa between 0.38 and 0.95), with high and consistent concordance between endoscopic and US scores (weighted kappa between 0.76 and 0.90). On logistic regression analysis, moderate-to-severe endoscopic and US scores at 3 months were associated with a high risk of endoscopic activity at 15 months (odds ratio (OR): 5.2; 95% confidence interval (CI): 1.6-17.6 and OR: 9.1; 95% CI: 2.5-33.5, respectively).

CONCLUSIONS

Bowel US may be used as a surrogate of colonoscopy in assessing the short-term response of severe forms of UC to therapy. Both US score and endoscopic score after 3 months of steroid therapy predict outcome of disease at 15 months.

Predicting the clinical response to cytapheresis in steroid-refractory or -dependent ulcerative colitis using contrast-enhanced ultrasonography

OBJECTIVE

To evaluate the usefulness of transabdominal ultrasound (US), including contrast-enhanced ultrasonography (CEUS), in predicting the response to cytapheresis therapy in patients with steroid-refractory or -dependent ulcerative colitis (UC).

MATERIAL AND METHODS

Between January 2005 and June 2008, 26 consecutive patients with steroid-refractory or -dependent UC were treated with granulocyte and monocyte adsorption apheresis (GCAP) or leukocytapheresis (LCAP) at our institute. The clinical activity of UC was evaluated by patients' C-reactive protein (CRP) levels and clinical activity index (CAI) scores. All patients were evaluated by grey-scale US, power Doppler US (PDUS), and CEUS. In CEUS, the color signal patterns were classified as 1 of 2 patterns. In pattern 1, color signals were partially detected in the bowel wall (excluding muscularis propria, the outer thin layer of the bowel wall), whereas in pattern 2, color signals were detected in the entire bowel wall (excluding muscularis propria). Differences between remission or clinical response (group R) and no response (group N) were ascertained for clinical features, clinical activities, and US findings.

RESULTS

Differences between the two groups were not considered significant for the clinical features, clinical activities, and grey-scale US and PDUS findings. Using CEUS, 4 patients in group R showed pattern 2 (21%), while in group N, all patients showed this pattern, indicating a significant difference between the two groups (p<0.01).

CONCLUSION

CEUS findings may be helpful in predicting the clinical response to cytapheresis for steroid-refractory or -dependent UC.

Application of transabdominal ultrasound in the detection of inflammatory bowel disease

As the incidence of inflammatory bowel disease (IBD) increases in recent years, accurate diagnosis of the disease becomes much more important. Moreover, the wide use of new targeted drugs requires precise evaluation of their therapeutic effects. Transabdominal ultrasound, as a newly emerging noninvasive method, plays an important role in diagnosing IBD, evaluating disease activity, and observing therapeutic effects. In this article, we will review the application of transabdominal ultrasound in the detection of IBD.

Prospective evaluation of the value of magnetic resonance imaging in suspected acute sigmoid diverticulitis

PURPOSE

The purpose of this study was to prospectively investigate patients with suspected acute colonic diverticulitis and to provide sensitivity, specificity, and interobserver agreement in a blinded trial.

METHODS

Fifty-five patients (29 men; 59 +/- 13 (range, 29-76) years) who reported to the emergency room with clinically suspected acute colonic diverticulitis were prospectively included in the study. All patients underwent magnetic resonance imaging scans of their abdomen before and after contrast agent administration. Two assessors blinded to all clinical, laboratory, and radiologic results evaluated the images separately.

RESULTS

The assessors reported colonic wall thickening, segmental narrowing of the colon, presence of diverticula, pericolic fatty infiltration, ascites, and abscesses. The assessors had to diagnose or rule out acute colonic diverticulitis. Sensitivities, specificities, positive, and negative likelihood ratios were derived. To determine interobserver agreement, a Cohen's kappa coefficient was calculated. The two assessors exhibited sensitivities of more than 94 percent, specificities of 88 percent, positive likelihood ratios of more than 7.5, and negative likelihood ratios of less than 0.07. The kappa coefficient showed a significant, strong correlation between both assessors (kappa = 0.68).

CONCLUSIONS

Magnetic resonance imaging is investigator independent and provides high sensitivity and specificity for the diagnosis of acute colonic diverticulitis.

Bowel ultrasound in Crohn's disease: surgical perspective

BACKGROUND

Bowel ultrasound has been proven to be a useful tool in the management of Crohn's disease, particularly in the assessment of intra-abdominal complications, most of which require surgery.

MATERIALS AND METHODS

The National Library of Medicine has been searched for articles on the use of bowel ultrasound in Crohn's disease focusing on aspects of interest to the surgeon.

RESULTS AND CONCLUSIONS

Several studies have demonstrated that bowel ultrasound may be useful to reduce the risk of unnecessary laparotomy in patients presenting acute abdomen with suspected chronic inflammatory bowel disease. Bowel ultrasound has been proven to be of value in the follow-up of Crohn's disease patients since allowing early diagnosis of intra-abdominal complications and, therefore, optimising the diagnostic and surgical approach. At followup, bowel ultrasound may accurately diagnose early postoperative complications and long-term disease recurrence. In patients submitted to conservative surgery, ultrasonography reveals changes in diseased bowel walls that may be predictive of recurrence of the disease, and hence determinant in the choice of medical treatment.

Ingested matter affects intestinal lesions in Crohn's disease

BACKGROUND

Environmental factors of the modern Western lifestyle may trigger Crohn's disease (CD) in susceptible individuals. Because such factors could be part of ingested matter, we intended to improve intestinal Crohn's lesions by exclusion thereof.

METHODS

At first we tested a highly restricted diet (based on spelt bread and red meat, both derived from intensively monitored organic farming) in 5 pilot cases. In a subsequent controlled trial, 18 patients with mild-to-moderate CD were randomly assigned to receive either this active diet or a control diet (low-fiber, low-fat, and high-carbohydrate). Mucosal improvement was assessed by magnetic resonance imaging (MRI) and endoscopy. Secondary endpoints included sonography, the Crohn's Disease Activity Index (CDAI), and the Inflammatory Bowel Disease Questionnaire (IBDQ).

RESULTS

Four of 5 pilot patients showed significant improvement within 4 weeks. From 18 patients in the controlled trial, 8 were randomized to the active and 10 to the control group; 4 decided to quit immediately after dietary counseling, 3 in the active and 1 in the control group (P = 0.183). At 6 weeks MRI and endoscopy showed improvement of intestinal lesions in 3 of 4 assessable patients of the active group and 1 of 9 patients of the control group (P = 0.027). Sonography showed improvement in 4 of 5 patients of the active group and in 1 of 8 assessable patients of the control group (P = 0.016). CDAI and IBDQ improved in both groups to a similar extent.

CONCLUSIONS

Ingested matter as part of the modern Western lifestyle may cause persistence of intestinal Crohn's lesions.

Technology Insight: new techniques for imaging the gut in patients with IBD

Advances in techniques for imaging the gut continue to drive the rapid development of modalities for diagnosing and assessing the activity of IBD. Abdominal ultrasound and magnetic resonance enterography have shown great potential for the diagnosis of IBD and assessment of its distribution, with the benefit of avoiding radiation exposure and serving as a safe option for pregnant patients. CT enterography or CT enteroclysis, with neutral or negative contrast, seems to be a sensitive and specific modality for detecting disease in the small bowel. The role of CT or magnetic resonance colonography in patients with IBD remains uncertain and these modalities are now best reserved for patients who decline or cannot undergo standard endoscopic evaluations. Capsule endoscopy might be the most sensitive modality for the detection of mucosal small bowel disease, but its specificity remains in question. Double-balloon endoscopy is an exciting new tool that has the distinct advantage of enabling biopsy or treatment of lesions detected during the procedure. All these techniques are at the forefront of the rapidly evolving field of imaging the gut in patients with IBD.

Colonic diseases: the value of US examination

The colon is affected by a number of diseases, mainly inflammatory, ischemic, and neoplastic conditions. Depending upon clinical indications endoscopy, US, CT, or other radiological methods are used for evaluation. The fact that US is frequently used as the initial imaging method in patients with non-specific clinical symptoms allows for greater influence in further diagnostic evaluation and with treatment, provided the investigator is familiar with the features of different intestinal diseases. This article will describe the anatomical characteristics of the colon, the US technique for examination of the colon, and the typical US features of the more common diagnoses of the colon.

Sonographic evaluation of inflammatory bowel disease: a prospective, blinded, comparative study

BACKGROUND

Children with inflammatory bowel disease (IBD) undergo invasive and repeated investigations, including contrast radiology and endoscopy.

OBJECTIVE

To assess transabdominal sonography of the colon and distal ileum compared to colonoscopy and barium radiology in known or suspected IBD.

MATERIALS AND METHODS

A prospectively recruited cohort of 44 children (median age 12 years, range 3.5-16.5 years; 24 males) underwent transabdominal sonography prior to colonoscopy (n=33) or barium follow-through (n=25). Diagnoses were: Crohn disease (n=25), ulcerative colitis (n=12), indeterminate colitis (n=1), normal (n=6).

RESULTS

Bowel wall thickness (BWT) and endoscopic severity were compared in 153 colonic segments. No difference was found between normal and mildly affected segments. BWT was less in normal bowel than moderate (P<0.001) or severe (P<0.001) lesions. Where BWT was >2.9 mm, sensitivity for moderate/severe disease was 48%, specificity 93%, positive predictive value 83% (likelihood ratio 7). Barium radiology showed terminal ileum abnormality in ten patients (40%). Where ileal BWT was >2.5 mm, comparative sensitivity was 75%, specificity 92%, positive predictive value 88% (likelihood ratio 9). Superior mesenteric artery Doppler did not correlate with disease severity.

CONCLUSION

Increased BWT has good positive predictive value for moderate/severe disease in the colon proximal to the rectum (>3 mm), and terminal ileum (>2.5 mm). BWT below this cannot exclude moderate/severe mucosal lesions.

Combined use of noninvasive tests is useful in the initial diagnostic approach to a child with suspected inflammatory bowel disease

OBJECTIVE

To assess the effectiveness of the combined use of fecal calprotectin (FC), anti-Saccharomyces cerevisiae antibody (ASCA), perinuclear staining antineutrophil antibody (pANCA), small intestinal permeability test (IP), and bowel wall ultrasonography measurement (BWUS) in the diagnostic work-up of children with suspected inflammatory bowel disease (IBD).

METHODS

All children referred for initial assessment of possible IBD were eligible. Patients with symptoms or signs (right-lower quadrant mass, perianal disease, or hematochezia) mandating a complete work-up for IBD were excluded. All enrolled patients underwent a clinical, laboratory, radiographic, and endoscopic evaluation including biopsy examinations. The immunoglobulin (Ig)G and IgA ASCA, IgG pANCA, FC, IP, and BWUS were tested in all patients at the initial assessment.

RESULTS

A final diagnosis of IBD was made in 27 patients: 17 Crohn disease and 10 ulcerative colitis. Eighteen children had other gastrointestinal diagnoses (8 functional bowel disorders, 5 food allergy-mediated diseases, 4 infectious enterocolitis, 1 familial Mediterranean fever). In patients with simultaneous abnormal values of FC, BWUS, and ASCA/pANCA, the estimated probability of having IBD was 99.47%. Patients with negative results on all tests had a 0.69% of probability of IBD.

CONCLUSIONS

The incorporation of noninvasive diagnostic tests into the initial diagnostic approach may avoid unnecessary invasive procedures and facilitate clinical decision-making when the diagnosis of IBD in children is initially uncertain.

Ultrasound and magnetic resonance imaging assessmentof active bowel segments in Crohn's disease

AIM

Determining bowel disease activity in Crohn's patients can be difficult on clinical and laboratory assessment. Endoscopy is invasive and barium studies use ionising radiation. The aim of this study was to compare ultrasound and magnetic resonance imaging (MRI) in detecting Crohn's disease activity in the small or large bowel.

MATERIALS AND METHODS

Thirty patients, previously diagnosed with Crohn's disease, had bowel ultrasound and MR imaging, and were deemed active or inactive on each test. The 'gold standard' was based on clinical assessment and one or more of the following: endoscopy, barium studies or surgery.

RESULTS

For determining Crohn's disease activity, the sensitivities and specificities of bowel ultrasound and MRI were 87 percent and 100 percent, and 87 percent and 71 percent, respectively. Significant parameters that defined disease activity were bowel wall thickening on ultrasound and MRI, and contrast enhancement of the bowel wall and mesenteric vascularity/stranding on MRI.

CONCLUSION

Ultrasound and MRI were both sensitive for determining Crohn's disease activity in the bowel, but MRI with gadolinium enhancement was less specific.

Dynamic studies of gadolinium uptake in brain tumors using inversion-recovery echo-planar imaging

Echo-planar imaging has been used to observe the dynamics of Gd-DTPA uptake in brain tumors. It has been possible to examine both vascular uptake and diffusion across the blood-brain barrier in a single experiment, by using the IR-MBEST echo-planar sequence which combines a high temporal resolution (approximately 3 s) with strong T1 weighting. To model the uptake it is necessary to know the arterial concentration of Gd-DTPA; in this study the signal in the sagittal sinus was measured to avoid the need to take repeated blood samples. The time constant for transfer across the blood-brain barrier was measured to be between 20 and 1050 s for different tumors. The results of the modeling correlated with the results of other assessments of tumor vascularity.