Prospective evaluation of high-frequency mini-probe ultrasound colonoscopic imaging in ulcerative colitis: a valid tool for predicting clinical severity

Advances in Endoscopy for Pediatric Inflammatory Bowel Disease

Endoscopic characterization of pediatric inflammatory bowel disease (IBD) has developed in accordance with advances in treatment and improved understanding of disease progression and complications. Reliable and consistent endoscopic reporting practices and tools continue to evolve. The roles of endoscopic ultrasonography, capsule endoscopy, and deep enteroscopy in the care of children and adolescents with IBD are beginning to be clarified. Opportunities for therapeutic intervention with endoscopy in pediatric IBD, including endoscopic balloon dilation and electroincision therapy, require further study. This review discusses the current utility of endoscopic assessment in Pediatric Inflammatory Bowel Disease, as well as emerging and evolving techniques to improve patient care.

Role of through-the-scope catheter-based EUS in inflammatory bowel disease diagnosis and activity assessment

BACKGROUND AND AIMS

Distinguishing Crohn's disease (CD) from ulcerative colitis (UC) may be difficult when the disease is limited to the colon. Transmural healing is an important adjunctive measure of inflammatory bowel disease activity. The aim of this study was to examine the role of EUS in differentiating CD versus UC and evaluating transmural disease activity.

METHODS

This prospective cohort study enrolled 20 patients with CD (10 active [aCD], 10 inactive), 20 patients with UC (10 active [aUC], 10 inactive), and 20 control subjects who underwent colonoscopy from 2019 to 2021 at a tertiary care center. Measurements of bowel wall layer thickness from the rectum and cecum were obtained using a through-the-scope US catheter (UM-3R-3; Olympus, Center Valley, Penn, USA) at the time of colonoscopy.

RESULTS

Compared with control subjects, patients with aCD had thicker rectal submucosa and total wall layer (submucosa median, 1.80 mm [interquartile range {IQR}, 1.40-2.00] vs .60 mm [IQR, .40-.70]; total wall median, 3.70 mm [IQR, 3.52-4.62] vs 2.10 mm [IQR, 1.70-2.40], respectively; P < .01). Similar significant findings were observed for the cecal wall layers. Compared with control subjects, patients with aUC had thicker rectal mucosa and total wall but not submucosa or muscularis propria layers (mucosa median, 1.35 mm [IQR, 1.12-1.47] vs .60 mm [IQR, .57-.70]; total wall median, 3.45 mm [IQR, 2.85-3.75] vs 2.10 mm [IQR, 1.70-2.40], respectively; P < .01). Patients with aCD compared with those with aUC had a significantly thicker rectal submucosa layer (median, 1.80 mm [IQR, 1.40-2.00] vs .55 mm [IQR, .40-.75], respectively, P < .01). Cutoff values of 1.1 mm for rectal submucosa in CD (sensitivity, 1.0; specificity, 1.0) and 1.1 mm for rectal mucosa in UC (sensitivity, .8; specificity, .9) were found to differentiate active from inactive disease.

CONCLUSIONS

EUS measurements of colon wall layers can help diagnose aCD versus aUC and assess transmural disease activity. (Clinical trial registration number: NCT03863886.).

The Use of Endoscopic Ultrasonography in Inflammatory Bowel Disease: A Review of the Literature

The diagnosis of inflammatory bowel disease (IBD) can sometimes be challenging. By corroborating clinical, imaging and histological data, the two main entities of IBD, ulcerative colitis and Crohn's disease (CD), can be differentiated in most cases. However, there remains 10-20% of patients where the diagnosis cannot be accurately established, in which case the term "IBD unclassified" is used. The imaging techniques most used to evaluate patients with IBD include colonoscopy, ultrasonography and magnetic resonance imaging. Endoscopic ultrasonography is mainly recommended for the evaluation of perianal CD. Through this work, we aim to identify other uses of this method in the case of patients with IBD.

Reliability of the Endoscopic Ultrasound Ulcerative Colitis (EUS-UC) score for assessment of inflammation in patients with ulcerative colitis

Background and study aims  Endoscopic ultrasound (EUS) may be a useful modality for disease assessment and risk stratification in ulcerative colitis. We assessed the reliability of a newly developed EUS index of inflammation called the EUS-Ulcerative Colitis (EUS-UC) score. Patients and methods  The EUS-UC score components include total wall thickness, hyperemia, and depth of inflammation (DOI). Three blinded expert endosonographers assessed EUS videos of 58 patients with UC in triplicate. Intra- and inter-rater reliability of the hyperemia and DOI component scores were estimated using intra-class correlation coefficients (ICCs). Total wall thickness reliability estimates could not be assessed in this study. The ICCs were compared to the original indices from which they were derived. Results  For hyperemia, the inter-class ICC was "moderate" at 0.556 (95 % CI = 0.434-0.651) and the intra class ICC was "almost perfect" at 0.884 (95 % CI = 0.835-0.920). The newly defined hyperemia score performed better than the original index from which is was derived. The DOI inter-class ICC was "fair" at 0.335 (95 % CI = 0.201-0.464), and the intra-class ICC was "substantial" at 0.732 (95 % CI = 0.642-0.802). The DOI reliability estimates were similar to the original index from which it was derived. Conclusions  The hyperemia component of the EUS-UC score performed significantly better than the original index from which it was derived, but the reliability of the DOI component was suboptimal. Intra-class correlation was excellent for both components. The EUS-UC score is a promising instrument for assessment of UC and further validation is required.

Quantitative characterization of the colorectal cancer in a rabbit model using high-frequency endoscopic ultrasound

PURPOSE

Colonoscopy accompanied with biopsy works as the routine endoscopic strategy for the diagnosis of colorectal cancer (CRC) in clinic; however, the colonoscopy is limited to the tissue surface. During the last decades, enabling technologies are emerging to complement with the colonoscopy for better administration of CRC. The conventional low-frequency (<12 MHz) endoscopic ultrasound (EUS) guided fine-needle aspiration (FNA) has been widely used to assess the lesion penetration. With the high-frequency ultrasound transducer (>20 MHz), EUS allows more precise visualization of the colorectal abnormalities. In order to achieve the accurate detection or in situ characterization of the colorectal lesions, the EUS diagnosis needs more patho-physiological related information in the micro-structural or molecular level. Quantitative ultrasound (QUS) technique, which could extract the micro-structural information from the ultrasound radio-frequency (RF) signal, is promising for the non-invasive tissue characterization. To date, the knowledge of the high-frequency endoscopic QUS for the CRC characterization has not been fully determined.

METHODS

In this work, to our best knowledge, it is the first application of the QUS technique based on a customized high-frequency EUS system (30.5 MHz center frequency) to characterize the colorectal malignancies in a VX2 rabbit CRC model. To eliminate the response from the ultrasound electronic system and transducer, the ultrasound signals from colon tissue were calibrated. And, the resulting quasi-liner ultrasound spectra were fit by the linear regression test. As a result, three spectral parameters, including the slope (k), intercept (I) and Midband Fit (M), were obtained from the best-fit line. The three spectral parameters were compared between the malignant tissue regions and adjacent normal tissue regions of the colon tissue specimen ex vivo. The independent t-test was conducted between the three parameters from the normal and malignant group. The statistical method of Fisher Linear Discriminant (FLD) was used to explore the linear combinations of the three parameters, so as to provide more tissue micro-structural features than the single parameter alone. The three FLD values were derived from three different combinations among k, I and M. The threshold was selected from the statistical analysis to optimize the differentiation criteria between the malignant and the normal tissues. The color-coded images were used to display the local FLD values and combined with the EUS B-mode image.

RESULTS AND CONCLUSIONS

The mean Midband Fit (M) and intercept (I) showed significant differences between the malignant and normal tissue regions. The statistical analysis showed that there were significant differences in all the mean FLD values of the spectral parameter combinations (kI, kM and IM) (t test, P < 0.05). And, the combined image result from the B-mode image and color-coded image could visually correlate with the histology result. In conclusion, the high-frequency endoscopic QUS technique was potential to be used as a complementary method to distinguish the colorectal malignancies by leveraging its morphological and micro-structural ultrasound information.

The role of intestinal ultrasound in diagnostics of bowel diseases

Intestinal ultrasound is a safe and inexpensive method that allows visualisation of the gastrointestinal tract and detection of abnormalities. This examination involves the use of two different ultrasound transducers: a low-frequency convex probe and high-frequency linear probe. When needed, the performance of these methods can be enhanced by the use of contrast media or Doppler techniques. Intestinal ultrasound is mostly utilised for the diagnosis and follow-up of patients with inflammatory bowel diseases, helping to avoid frequent use of invasive and expensive diagnostic procedures and leading to early implementation of suitable treatment. This technique can also serve to detect other pathologic conditions that are present in the gastrointestinal tract. It is a promising method with high sensitivity and specificity, which has gained popularity in recent years and has the potential to become the method of choice in the diagnostics of many intestinal disorders.

Reliability of EUS indices to detect inflammation in ulcerative colitis

BACKGROUND AND AIMS

EUS is a potentially useful modality to assess severity of inflammation in ulcerative colitis (UC). We assessed the reliability of existing EUS indices and correlated them with endoscopic and histologic scores.

METHODS

Four blinded endosonographers assessed 58 endoscopic and EUS videos in triplicate, from patients with UC. Intrarater and interrater reliability of the hyperemia and Tsuga scores were estimated by using intra-class correlation coefficients (ICCs). Correlation with the Mayo endoscopy score, modified Baron score (MBS), Ulcerative Colitis Endoscopic Index of Severity (UCEIS), and Geboes histopathology score (GHS) were calculated by using bootstrapping methods. A RAND consensus process led to development of standardized definitions and a revised EUS-UC score.

RESULTS

ICCs for intrarater reliability were 0.76 (95% confidence interval [CI], 0.71-0.80) for the hyperemia score and 0.85 (95% CI, 0.79-0.89) for the Tsuga score. Corresponding values for interrater reliability were 0.34 (95% CI, 0.25-0.42) and 0.36 (95% CI, 0.24-0.46). Correlation between hyperemia and Tsuga scores to Mayo scoring system, MBS, UCEIS, and the GHS were 0.39 (95% CI, 0.15-0.61) and 0.28 (95% CI, 0.04-0.51), 0.38 (95% CI, 0.16-0.57) and 0.25 (95% CI, -0.01-0.48), 0.41 (95% CI, 0.16-0.62) and 0.27 (95% CI, 0.01-0.50), 0.37 (95% CI, -0.01-0.48) and 0.24 (95% CI, 0.13-0.57), respectively. The revised EUS-UC score included bowel wall thickening, depth of inflammation, and hyperemia.

CONCLUSIONS

Although substantial to almost perfect intrarater agreement existed for EUS indices in UC, interrater agreement was fair. Standardization of item definitions with development of a revised evaluative instrument has potential application as an evaluative and prognostic tool for UC. (Clinical trial registration number: NCT01852760.).

Defining Disease Severity in Inflammatory Bowel Diseases: Current and Future Directions

Although most treatment algorithms in inflammatory bowel disease (IBD) begin with classifying patients according to disease severity, no formal validated or consensus definitions of mild, moderate, or severe IBD currently exist. There are 3 main domains relevant to the evaluation of disease severity in IBD: impact of the disease on the patient, disease burden, and disease course. These measures are not mutually exclusive and the correlations and interactions between them are not necessarily proportionate. A comprehensive literature search was performed regarding current definitions of disease severity in both Crohn's disease and ulcerative colitis, and the ability to categorize disease severity in a particular patient. Although numerous assessment tools for symptoms, quality of life, patient-reported outcomes, fatigue, endoscopy, cross-sectional imaging, and histology (in ulcerative colitis) were identified, few have validated thresholds for categorizing disease activity or severity. Moving forward, we propose a preliminary set of criteria that could be used to classify IBD disease severity. These are grouped by the 3 domains of disease severity: impact of the disease on the patient (clinical symptoms, quality of life, fatigue, and disability); measurable inflammatory burden (C-reactive protein, mucosal lesions, upper gastrointestinal involvement, and disease extent), and disease course (including structural damage, history/extension of intestinal resection, perianal disease, number of flares, and extraintestinal manifestations). We further suggest that a disease severity classification should be developed and validated by an international group to develop a pragmatic means of identifying patients with severe disease. This is increasingly important to guide current therapeutic strategies for IBD and to develop treatment algorithms for clinical practice.

Utilization of High-frequency Mini Probe Ultrasound in the Assessment of Colonic Wall Thickness in Patients With Diverticular Disease: A Feasibility Study

BACKGROUND

Assessment of diverticular disease (DD) is routinely undertaken by colonoscopy and computed tomography (CT) scan. Improvements in high-frequency ultrasound have enabled evaluation of the colon wall structure in detail. Our objective was to assess ultrasound in measuring colonic wall thickness in DD.

METHODS

High-frequency 20-MHz ultrasound was undertaken to measure individual layer and total colonic wall thickness. Case patients had symptomatic DD. Control patients underwent colonoscopy for other reasons. Select patients also underwent abdominal CT scan.

RESULTS

Thirty-three patients underwent colonoscopic ultrasound, 18 with sigmoid diverticula and 15 control patients.Total wall thickness was greater in patients with DD, 5.69 mm (1.68) versus 2.61 mm (1.29, P<0.0001). Patients with DD had significant thickening in each individual layer of the colonic wall measured (each P<0.0001).Greatest differences were in the muscularis propria, which was an average of 3.5 times thicker in patients with DD. In patients with DD, the segment of colonic wall measured was also thicker, with average mid-sigmoid thickness of 23.0 mm (SD 9.6 mm).

CONCLUSIONS

Patients with DD have increased sigmoid thickness when compared with controls, especially the muscularis propria. Unlike CT, ultrasound was also able to identify thickening in the mucosa and submucosa.

Endoscopic ultrasound of the colon for the differentiation of Crohn's disease and ulcerative colitis in comparison with healthy controls

BACKGROUND

Diagnosis of inflammatory bowel disease (IBD) is based on clinical presentation, colonoscopy and histology. Differentiation of Crohn's disease (CD) and ulcerative colitis (UC) can be difficult in some patients. Endoscopic ultrasound (EUS) provides high resolution images of the gastrointestinal wall (GI) and may be an alternative to differentiate CD/UC.

AIM

EUS of the GI layers in patients with IBD and healthy controls (HC) for the differential diagnosis of UC/CD in a prospective, blinded study.

METHODS

Consecutive patients with CD, UC or HC underwent EUS in the mid sigmoid colon with a forward-viewing radial echoendoscope. Mucosal, submucosal, total wall thickness (TWT) and locoregional lymphnodes (LN) were assessed by EUS in a blinded fashion. TWT was correlated with macroscopic IBD scores and histological inflammation scores.

RESULTS

Total wall thickness of 61 HC was 1.71 ± 0.02 mm, and 3.51 ± 0.15 mm in n = 52 with active IBD. In patients with active UC significant thickening of the mucosa was observed but nearly normal submucosa and m.propria. In active CD significant thickening of the submucosal layer was seen with nearly normal mucosa and m.propria [MucosaUC  = 2.08 ± 0.11 mm, MucosaCD  = 1.32 ± 0.17 mm (P = 0.0001); SubmucosaUC  = 1.01 ± 0.08 mm, SubmucosaCD  = 2.01 ± 0.22 mm (P = 0.0001)]. In 73.7% of patients with active CD, but in none with UC, paracolonic lymph nodes were detected. When mucosal-submucosal and TWT and LNs were combined, the sensitivity was 92.3% for the differentiation of active UC/CD. There was a strong correlation of TWT with histological inflammation scores (UC: r = 0.43; CD: r = 0.69).

CONCLUSIONS

Increased total wall thickness has a high positive predictive value for active IBD. EUS can differentiate active UC from CD and quantify the level of colonic inflammation.

High-frequency mini probe ultrasound before endoscopic resection of colorectal polyps--is it useful?

BACKGROUND

Endoscopic resection of benign colorectal polyps and early cancer is well established. Local staging is of paramount importance to ensure that local resection is feasible. Endoscopic ultrasound has been used to evaluate the depth of lesions in the rectum, but its use in the colon is limited.

OBJECTIVE

This prospective study aims to evaluate the accuracy of 20-MHz mini probe ultrasound before the endoscopic resection of colorectal tumors.

DESIGN

All patients underwent 20-MHz high-frequency mini probe ultrasound of the colorectal lesion during colonoscopic examination. The mini probes were inserted through the working channel of the colonoscope, and acoustic coupling was achieved by instilling water to completely submerge the lesion. The depth of infiltration of the colorectal tumor was identified before resection. The lesions were sent for histological examination, and the level of infiltration was compared with the preoperative ultrasound depth.

SETTING

This study was conducted at a tertiary referral university teaching hospital.

PATIENTS

Consecutive patients referred for consideration of endoscopic resection were included in the study.

INTERVENTIONS

All patients were subject to colonoscopic high-frequency mini probe ultrasound to evaluate the depth of lesion before local resection.

MAIN OUTCOME MEASURES

There were 2 outcome measures: the ultrasound depth of colorectal lesion and the histological depth.

RESULTS

One hundred four patients were included with a mean age of 70 years. The surgical procedures included 59 endoscopic mucosal resections, 36 transanal endoscopic microsurgeries, and 9 endoscopic submucosal dissections. The 20-MHz ultrasound correctly staged 100 of 104 lesions, an overall accuracy of 96.1%. Eighty-eight of 89 mucosal lesions and 11 of 12 submucosal lesions were correctly staged.

LIMITATIONS

The ultrasound examination was performed by the main author only and is therefore dependent on his experience alone.

CONCLUSION

Colonoscopic high-frequency mini probe ultrasound has high accuracy in determining the depth of colorectal lesion and is useful before endoscopic resection.

Ultrasonographic evaluation of bowel wall thickness and intramural blood flow in ulcerative colitis

Aim. This study aimed at assessing Doppler ultrasonographic findings of gut wall vessels and thickness in active and quiescent ulcerative colitis. Methods. Fifty patients with ulcerative colitis were studied using transabdominal grayscale and Doppler sonography of sigmoid, distal and middle parts of descending colon in different stages of the disease. Thickness of colon wall in the most involved site, number of color signals in each box, resistive index (RI), and pulsatility index (PI) were evaluated. Results. The median thickness of the colon wall in the most involved sites was 4.3 mm in acute phase and 4.4 mm in the inactive phase (P = 0.47). The median number of the color signals in the active phase at the most involved site, distal part of descending colon and sigmoid was higher than that of the color signals in the inactive phase (P = 0.0001). In the most involved site, the PI and RI were undetectable in the inactive phase. The median PI was 1.4 in the mild phase, 1.3 in the moderate phase, and 1.1 in the severe phase (P = 0.002). Conclusion. In contrast to the colon wall thickness, increased intramural blood flow reflected the clinical severity in ulcerative colitis patients.

Features of in vitro ultrasound biomicroscopic imaging and colonoscopy for detection of colon tumor in mice

The present work tested the capability of ultrasound biomicroscopy (UBM), at 45 MHz, to provide cross-sectional images with appropriate resolution and contrast to detect tumors and determine their penetration depths on the colon of mice, Mus musculus (Linnaeus 1758), treated with carcinogen for colon tumor induction. B-mode images were obtained, in vitro, from each animal (13 treated and 4 untreated) colon opened longitudinally and immersed in saline solution at room temperature. Prior to UBM inspection, all animals were also examined by colonoscopy. The layers of normal colon identified by UBM are: mucosa (hyperechoic), muscularis mucosae (hypoechoic), submucosa (hyperechoic) and muscularis externa (hypoechoic). UBM images of colon lesions presented structures corresponding to tumors (hyperechoic), lymphoid hyperplasia (hypoechoic) and polypoid tumors (hyperechoic). Additionally, tumoral lesion invasion through the colon was also identified. When compared with histopathologic analysis, all colon lesions detected by UBM were confirmed, while colonoscopic findings had two false negatives.

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.

Role of endoscopic ultrasonography in predicting the response to cyclosporin A in ulcerative colitis refractory to steroids

BACKGROUND AND AIMS

Although cyclosporin A has been reported to be effective in the treatment of severe ulcerative colitis, factors predicting its therapeutic efficacy remain unclear. Technical progress in endoscopic ultrasonography has improved visualisation of the structure of the colon wall. Here, to assess the value of endoscopic ultrasonography in predicting the response to cyclosporin A treatment, we evaluated the therapeutic effect of cyclosporin A by determining the pre- and post-cyclosporin A thickness of the mucosal layer in the rectum using endoscopic ultrasonography with an ultrasonic catheter probe.

PATIENTS AND METHODS

Fifteen ulcerative colitis patients who did not respond to high-doses of corticosteroids were treated with cyclosporin A by continuous intravenous infusion at 4mg/kg/day for 20 days. Before and 20 days after cyclosporin A therapy, clinical disease activity was assessed using clinical activity index scores. Colonoscopy and endoscopic ultrasonography were undertaken before and 20 days after cyclosporin A therapy.

RESULTS

Following treatment with cyclosporin A, nine patients showed a decrease in clinical activity index score by six points or more and were defined as responders, while the other six were defined as non-responders. Endoscopic ultrasonography measurement using an ultrasonic catheter probe showed that thickness of the rectal mucosal layer before cyclosporin A was significantly greater in responders than in non-responders (p<0.05). Further, thickness after cyclosporin A was statistically decreased (p<0.01) in the responders but not in the non-responders.

CONCLUSIONS

The ultrasonic catheter probe may represent a useful means of predicting and evaluating the efficacy of cyclosporin A treatment in severely ill ulcerative colitis patients.

Grey-scale and colour Doppler sonography in the evaluation of children with suspected bowel inflammation: correlation with colonoscopy and histological findings

AIM

To evaluate the correlation of grey-scale and colour Doppler sonography with colonoscopy and histology to detect bowel inflammation in children.

MATERIAL AND METHODS

The records of 72 patients with suspected bowel inflammation were reviewed retrospectively. Patients were included in the study if sonography had been performed up to 30 days before colonoscopy. Grey-scale and colour Doppler sonography were used to evaluate bowel wall thickness and vascularity for the detection of distal bowel inflammation. Findings were correlated with colonoscopy and histological findings. The sensitivity and specificity of sonographic wall thickness to detect inflammation was determined. Spearman's coefficient (rs) was used to determine the correlation of Doppler findings with colonoscopy/histology.

RESULTS

Sonograms of 372 bowel segments were evaluated and results were correlated with colonoscopy and histological findings of 352 segments. The sensitivity and specificity of sonographic bowel thickness to detect inflammation in the terminal ileum and the right colon were high; in the other segments, specificity was high but sensitivity was low. The correlation of Doppler sonography with colonoscopy and histology to detect inflammation in the terminal ileum was strong (rs: 0.84; p<0.001) and in the other segments, weak to moderate; when the interval between examinations was shorter than 10 days, the correlation was stronger in all segments. Of nine patients with abnormal small bowel sonograms but normal colonoscopies, three had Crohn's disease.

CONCLUSION

Sensitivity and specificity of grey-scale sonography to detect inflammation in the terminal ileum and the right colon were high, and the correlation of Doppler with colonoscopy and histology was very strong in the same segments.

Value of colonoscopy for prediction of prognosis in patients with ulcerative colitis

Ulcerative colitis (UC) is a chronic inflammatory bowel disorder characterized by exacerbations and remissions. Some UC patients remain refractory to conventional medical treatment while, in others, the effectiveness of drugs is limited by side-effects. Recently, cyclosporine and leukocyte removal therapy have been used for refractory UC patients. To predict the efficacy of these therapies is important for appropriate selection of treatment options and for preparation for colectomy. Endoscopy is the cornerstone for diagnosis and evaluation of UC. Endoscopic parameters in patients with severe or refractory UC may predict a clinical response to therapies, such as cyclosporine or leukocyte removal therapy. As for the patients with quiescent UC, relapse of UC is difficult to predict by routine colonoscopy. Even when routine colonoscopy suggests remission and a normal mucosal appearance, microscopic abnormalities may persist and relapse may occur later. To more accurately identify disease activity and to predict exacerbations in UC patients with clinically inactive disease is important for deciding whether medical treatment should be maintained. Magnifying colonoscopy is useful for the evaluation of disease activity and for predicting relapse in patients with UC.