Spectrum of normal and abnormal CT appearances of the ileocecal valve and cecum with endoscopic and surgical correlation

The ileocecal valve in transabdominal ultrasound. Part 2: Pathological lesions

The aim of this paper is to present our experience in transabdominal ultrasonography of ileocecal valve lesions. The ileocecal valve, located in the central part of the ileocecal bowel segment, is rarely the primary site of disease processes. It is usually involved by pathologies in adjacent bowel segments. These are primarily infectious diseases such as yersiniosis, campylobacteriosis and salmonellosis. Typical location of Crohn's lesions also promotes valve involvement. The appearance of the lesions in these cases is characterized by a symmetrical submucosal thickening of the bowel involved over a longer segment. Non-malignant valvular hyperplasia is relatively commonly identified as lipomatosis, manifested by symmetrical enlargement and smooth outlines. However, valvular lipoma causing an asymmetrical hyperechoic bulge is a rare finding. ileocecal valve lipomatosis or lipoma should not be misdiagnosed as a lipoma of the cecoascending part of the colon and, the other way round, a right colonic lipoma should not be mistaken for a fatty valve. Polyps on the ileocecal valve, although sometimes detected, were not identified in our material. Adenocarcinoma, which is found in the cecum in approximately ¼ of cases, is the most common malignancy, followed by neuroendocrine tumor and, rarely, lymphoma. In three cases of malignant involvement of the ileocecal valve, we observed irregular hypoechoic thickening with complete loss of wall stratification, with the lesions causing symptoms of small bowel obstruction in two of these cases. The nearly forgotten ileocecal valve syndrome, also known as Bauhin's ileocecal valve syndrome, characterized by intermittent right iliac fossa pain, is also briefly discussed. Transabdominal ultrasound can be used as an initial diagnostic tool in some of these pathologies.

The ileocecal valve in transabdominal ultrasound Part 1: Sonographic anatomy and technique

The ileocecal valve is a part of the gastrointestinal tract that separates two intestinal segments differing in both anatomy and function. Dysfunction or surgical removal of the valve usually results in the development of small intestinal bacterial overgrowth syndrome. The available literature lacks a broader discussion and ultrasound presentation of the ileocecal valve. The aim of this study is to present our experience in transabdominal ultrasound of the ileocecal valve in comparison with colonoscopic and computed tomography colonography data. In this part of the manuscript, we discuss the anatomical structures in the right iliac fossa that make up the ileocecal segment of the intestine. The ileocecal valve, which comes in two morphological forms: labial and papillary, is its central part. As shown in computed tomography colonography, the first type is more common, accounting for 76%, the second type accounts for 21%, whereas ileocecal valve lipomatosis is found in 3% of cases. Post-mortem studies have shown a significantly higher incidence of valve lipomatosis, which was found in up to 4 out of 5 cases. Our observations correspond with these findings. Ileocecal valve lipomatosis presents on ultrasound as a hyperechoic, well-circumscribed lesion, with no evident vascularity on color Doppler. This image should be differentiated especially from a lipoma, a relatively common large intestinal pathology. The paper presents two methods of preparation for an ultrasound scan (i.e. only on an empty stomach or after cleansing the intestine) and determines the optimal imaging methods for the ileocecal valve using transabdominal ultrasound. At the end of the ileocecal examination, it should be remembered to assess the lymph nodes in the right iliac fossa.

Assessment of Anatomical Morphology of the Ileocecal Junction and Ileocecal Valve by Dissection and Endoscopy

INTRODUCTION

The ileocecal valve (ICV) guards the opening of the ileocecal junction (ICJ) and acts as a mechanical barrier to prevent the reflux of material from the colon into the ileum. The morphology of the ICV noted in living is different from that of cadavers. The ICV is better studied in the living by endoscopy. A study of variation in the gross anatomy of the ICV can help determine the factors responsible for its competency.

MATERIALS AND METHODS

A descriptive study was conducted on a total of 85 (N) patients each in two groups over a period of two years. Group I: 85 specimens of the ileocecal region obtained during dissection; Group 2: 85 patients undergoing colonoscopic study undertaken in the Department of Medical Gastroenterology. In the dissection method, the apparently normal ICJ was inspected, photographed, and measured using Vernier calipers. In the colonoscopy method, the procedure was observed and while observing ICV, photos were taken. These photographs were later compared with other photographs in the literature to identify the morphology of ICV. The age, gender, location, and morphology of ICV were represented in percentile, and qualitative variables were analyzed by Pearson correlation coefficient.

RESULTS

Out of 85 participants in Group A, 80% (68) were males and 20% (17) were females; in Group B, 58% (49) were males, and the remaining 42% (36) were females. In the dissection method out of 85 (N) patients, 98% had reverse S type terminal ileum, correlation of diameter of ICV with age p=0.003 and correlation of morphology of ICV with age p=0.006, and was statistically significant. In the colonoscopy method, 58% were males and 22% of them were 31-40 years. In 49% of patients, ICV was viewed from the left lateral position. The correlation of success of ileoscopy with age (p=0.608), gender (p=0.896), the position of the patient (p=0.236), and morphology of ICV (p=0.631) was not statistically significant.

CONCLUSION

There were no age-related changes observed regarding the morphology of the ICJ. It was found that as age increases diameter of ICV increases. The success of ileoscopy was highest in 31-40 years of age.

Three-dimensional reconstruction of computed tomography colonography discloses anatomic features associated with colonoscopy failure

Objectives:

Three-dimensional virtual reality (3D VR) permits precise reconstruction of computed tomography (CT) images, and these allow precise measurements of colonic anatomical parameters. Colonoscopy proves challenging in a subset of patients, and thus CT colonoscopy (CTC) is often required to visualize the entire colon. The aim of the study was to determine whether 3D reconstructions of the colon could help identify and quantify the key anatomical features leading to colonoscopy failure.

Design:

Retrospective observational study.

Methods:

Using 3D VR technology, we reconstructed and compared the length of various colonic segments and number of bends and colonic width in 10 cases of CTC in technically failed prior colonoscopies to 10 cases of CTC performed for non-technically failure indications.

Results:

We found significant elongation of the sigmoid colon (71 ± 23 cm versus 35 ± 9; p = 0.01) and of pancolonic length (216 ± 38 cm versus 158 ± 20 cm; p = 0.001) in cases of technically failed colonoscopy. There was also a significant increase in the number of colonic angles (17.7 ± 3.2 versus 12.7 ± 2.4; p = 0.008) in failed colonoscopy cases.

Conclusion:

Increased sigmoid and pancolonic length and more colonic bends are novel factors associated with technical failure of colonoscopy.

A Practical Index to Distinguish Backwash Ileitis From Crohn's Terminal Ileitis in MR Enterography

BACKGROUND

Differentiating ulcerative colitis-associated "backwash" ileitis (BWI) from Crohn's terminal ileitis (CTI) is a diagnostic challenge and highly affects patient's management. This study aimed to investigate magnetic resonance enterography (MRE) features including ileocecal valve patency index (ICPI) in patients with BWI and CTI and distinguish these entities based on MRE findings.

METHODS

After obtaining institutional review board approval, we reviewed 1654 MREs; 60 patients with pathologically proven BWI (n = 30) and CTI (n = 30) were enrolled. Two radiologists who were blinded to the clinical diagnosis analyzed MREs. We evaluated bowel wall thickness and enhancement pattern, ileocecal valve (ICV) diameter, and lip thickness. Ileocecal valve patency index-T and ICPI-C were calculated to normalize the ICV diameter with respect to terminal ileum (TI) and cecum, respectively. An additional group of non-BWI-UC patients (n = 30) was also included to validate indices.

RESULTS

Circumferential mural thickening (90% vs 1%, P < .001) and inner-wall enhancement (P < .001) of TI were more frequent in BWI patients than CTI. Serosal irregularity (53% vs 13%, P = .002), higher mural thickness (5mm vs 3mm, P < .001), and asymmetric hyperenhancement (P < .001) of TI were more prevalent in CTI than BWI. Ileocecal valve patency and lip atrophy were significantly higher in BWI than CTI and non-BWI-UC groups (both P < .001). Ileocecal valve patency indices-C and ICPI-T indices were able to accurately distinguish BWI from CTI (area under the ROC curve [AUC], 0.864 and 0.847 for ICPI-T and ICPI-C, respectively) and non-BWI-UC (AUC, 0.777 and 0.791 for ICPI-T and ICPI-C, respectively). Ileocecal valve patency indices-T  ≥31.5% were 100% specific to distinguish BWI from CTI, but sensitivity was 63%.

CONCLUSIONS

Magnetic resonance enterography features of ICV and TI can accurately differentiate BWI from CTI. Two practical indices introduced in this study showed high specificity to distinguish BWI from CTI.

Ilececum: A Comprehensive Review

For gastrointestinal endoscopists, the ileocecum is the finishing line during colonoscopy and it is identified by three endoscopic landmarks: terminal ileum, ileocecal valve, and the appendiceal orifice. Although ileal intubation is recommended during routine screening colonoscopy, it is not required in most cases of screening colonoscopy. Ileal intubation is indicated in certain circumstances such as suspected inflammatory bowel disease and GI bleeding. There is much pathology that can be observed within the ileocecum. Careful and systematic examination should be stressed during GI endoscopic training and practice. In this review, the authors demonstrate its anatomy, endoscopic findings, and pathologies.

CT colonography interpretation: how to maximize polyp detection and minimize overcalling

This article outlines how to achieve maximum accuracy in interpreting CT colonography (CTC) regarding colonic findings. Interpreting extracolonic findings seen on CTC is a separate diagnostic task and will not be addressed in this article. While many interpretive pitfalls are in fact related to CTC techniques, this article focuses on issues that are related to interpretive knowledge and skills, avoiding in-depth discussions on CTC techniques. Principal methods and further tips for detecting possible polyp candidates and for confirming true soft-tissue polyps will be discussed. Specific points about optimizing interpretation strategies for difficult flat polyps including sessile serrated polyp will be raised. There are numerous interpretive pitfalls regarding the colonic interpretation of CTC. Knowledge of these pitfalls will shorten the learning curve and help achieve accurate reads.

Sonography of the Cecum: Gateway to the Right Lower Quadrant

Sonography of the cecum has come of age largely as a consequence of the successful evolution of appendiceal sonography as a useful tool in the evaluation of patients with right lower-quadrant pain. At some medical centers, graded-compression sonography (GCS) has become the initial imaging study of choice in the assessment of these individuals. The cecum serves as a helpful anatomic landmark for localization of the appendix in these examinations-providing a sonographic starting point in the search for the appendix. During GCS, primary pathology within the cecum itself can become evident, including a variety of processes, such as infectious, inflammatory, or neoplastic disorders, whose presentations commonly mimic that of appendicitis. The accurate diagnosis of cecal abnormalities and their differentiation from acute appendicitis play valuable roles in the management of affected patients because the options for further workup and subsequent treatment vary greatly according to the diagnosis at hand. Additionally, the compressed cecum often becomes an acoustic window into the right lower quadrant, revealing pathology apart from the appendix within the right iliac fossa. The purpose of this pictorial essay is to highlight the importance and value of performing a careful evaluation of the cecum during GCS of patients with suspected appendicitis and to review the differential diagnosis and imaging findings of primary cecal abnormalities whose clinical presentations can mimic that of acute appendicitis.

Current radiological strategies for the assessment of right lower quadrant abdominal pain

Right lower quadrant abdominal pain is a common clinical entity. Imaging and the radiologistplay an integral role in achieving a diagnosis, so guiding prompt management of patients.This review discusses the spectrum of pathology and imaging findings, and highlights and contrasts the preferred imaging modalities in different subsets of patients.

MDCT of acute cecal conditions

The cecum comprises a relatively short segment of the gastrointestinal tract, but it can be affected by numerous acute conditions. Acute conditions may arise from processes primary to the cecum, such as volvulus, bascule, neoplasm, and trauma. Alternatively, acute conditions can be due to secondary to systemic or nearby pathology, such as infection, inflammatory processes, ischemia, and infarction. While it is common to suspect appendicitis as the etiology of acute right lower quadrant abdominal pain, the cecum should also be considered as a potential cause of pain, especially in the setting of an abnormal or absent appendix. Multi-detector computed tomography (MDCT) has evolved to become the best imaging modality to evaluate patients presenting with right lower quadrant abdominal pain or suspected acute cecal pathology. Strengths of MDCT include rapid acquisition of images, high spatial resolution, and ability to create multi-planar reconstructed images. In this pictorial review, we illustrate and describe key MDCT findings for various acute cecal conditions with which the emergency radiologist should be familiar.

Progress in the diagnosis of ileocecal lesions

The ileocecal area includes the ileocecal valve, terminal ileum, cecum, appendix, and top ascending colon. Since this area may be affected by pathologic conditions that are either common throughout the gastrointestinal system or exclusive to this area, a great variety of intestinal diseases may arise in this region, making the diagnosis of ileocecal lesions difficult. In clinic, the diagnosis of ileocecal lesions depends on the combination of disease history, clinical features, imaging and endoscopic findings. The development of advanced imaging and endoscopy technology has greatly increased the detection rate of ileocecal lesions. In this review, we discuss the use of imaging and endoscopic examinations for evaluation of ileocecal area to help ensure accurate diagnosis and appropriate treatment.