Hydrogen peroxide enhanced ultrasound- fistulography in the assessment of enterocutaneous fistulas complicating Crohn's disease

Diagnostic Accuracy of Intestinal Ultrasound in the Detection of Intra-Abdominal Complications in Crohn's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Crohn's disease [CD] is frequently associated with the development of strictures and penetrating complications. Intestinal ultrasound [IUS] is a non-invasive imaging modality ideal for point-of-care assessment. In this systematic review and meta-analysis we provide a current overview on the diagnostic accuracy of IUS and its advanced modalities in the detection of intra-abdominal complications in CD compared to endoscopy, cross-sectional imaging, surgery, and pathology.

METHOD

We conducted a literature search for studies describing the diagnostic accuracy of IUS in adult patients with CD-related intra-abdominal complications. Quality of the included studies was assessed with the QUADAS-2 tool. Meta-analysis was performed for both conventional IUS [B-mode] and oral contrast IUS [SICUS].

RESULTS

Of the 1498 studies we identified, 68 were included in this review and 23 studies [3863 patients] were used for the meta-analysis. Pooled sensitivities and specificities for strictures, inflammatory masses, and fistulas by B-mode IUS were 0.81 and 0.90, 0.87 [sensitivities] and 0.95, and 0.67 and 0.97 [specificities], respectively. Pooled overall log diagnostic odds ratios were 3.56, 3.97 and 3.84, respectively. Pooled sensitivity and specificity of SICUS were 0.94 and 0.95, 0.91 and 0.97 [sensitivities], and 0.90 and 0.94 [specificities], respectively. The pooled overall log diagnostic odds ratios of SICUS were 4.51, 5.46, and 4.80, respectively.

CONCLUSION

IUS is accurate for the diagnosis of intra-abdominal complications in CD. As a non-invasive, point-of-care modality, IUS is recommended as the first-line imaging tool if there is a suspicion of CD-related intra-abdominal complications.

Intra-Cavitary Contrast-Enhanced Ultrasound: A Novel Radiation-Free Method for Detecting Abscess-Associated Penetrating Disease in Crohn's Disease

BACKGROUND AND AIM

Penetrating disease is a common condition complicating Crohn's disease [CD]. Establishing the presence of a fistula and the anatomical definition of the fistulous tracts are essential for deciding on appropriate treatment strategies. We aimed to assess the diagnostic accuracy of intra-cavitary contrast-enhanced ultrasound [IC-CEUS] for the detection of a fistulous tract associated with abscesses in CD patients.

METHODS

In this prospective cohort study, consecutive CD patients suspected of having an intra-abdominal abscess, who were referred for US-guided aspiration were recruited. IC-CEUS was performed by injecting diluted contrast agent [SonoVue] into the abscess cavity immediately following the ultrasound-guided needle abscess aspiration and drainage. The diagnostic accuracy of IC-CEUS in demonstrating the presence of fistulous tracts was compared with that of computed tomography enterography/magnetic resonance enterography [CTE/MRE], using surgical and gross pathological findings as the reference standard.

RESULTS

Thirty-one patients who underwent IC-CEUS and subsequent surgery were included in the final analysis. IC-CEUS demonstrated fistulous/sinus tracts in 26 of 31 participants with a sensitivity and specificity of 86.7 % (95% confidence interval [CI], 68.4-95.6%) and 100% [95% CI, 5.5-100.0%], respectively. Moreover, IC-CEUS correctly demonstrated fistulous/sinus tracts in 13 participants without delineation of fistulous/sinus tracts on CTE/MRE. Combining IC-CEUS and CTE/MRE, the fistula/sinus tract was clearly demonstrated in 29 patients [93.5%, 29/31]. The mean duration of the IC-CEUS procedure was 8.6 min [range 5.0-12.0]. No severe adverse events occurred during the IC-CEUS procedure.

CONCLUSION

In this pilot study, IC-CEUS accurately delineated the anatomical definition of fistulous/sinus tracts associated with intra-abdominal abscesses in CD patients. As a radiation-free and safe technique, IC-CEUS may be used as an alternative/adjunctive method to CTE/MRE for detecting penetrating disease in patients with CD.

Interventional radiologic management and treatment of enterocutaneous fistulae

Enterocutaneous fistulae (ECFs) are abnormal sinus tract communications between the alimentary system and skin surface that can cause significant management problems and cost to the health care system. Interventional radiology can play an important role in diagnosis and treatment when conventional measures fail and additional surgery is difficult or poses a high risk. The management of patients with fistulae requires operator ingenuity and dedication, a multidisciplinary team approach, and an understanding of the pathophysiology. This article reviews the major issues in ECF management and the role of interventional radiology.

Contemporary surgical management of rectovaginal fistula in Crohn's disease

Rectovaginal fistula is a disastrous complication of Crohn’s disease (CD) that is exceedingly difficult to treat. It is a disabling condition that negatively impacts a women’s quality of life. Successful management is possible only after accurate and complete assessment of the entire gastrointestinal tract has been performed. Current treatment algorithms range from observation to medical management to the need for surgical intervention. A wide variety of success rates have been reported for all management options. The choice of surgical repair methods depends on various fistula and patient characteristics. Before treatment is undertaken, establishing reasonable goals and expectations of therapy is essential for both the patient and surgeon. This article aims to highlight the various surgical techniques and their outcomes for repair of CD associated rectovaginal fistula.

Radiographic and endoscopic diagnosis and treatment of enterocutaneous fistulas

The management of enterocutaneous fistulas continues to be a challenging postoperative complication. Understanding the anatomy of the fistula optimizes its evaluation and management. Diagnostic radiology has always played an important role in this task. The use of plain radiography with contrasted studies and fistulograms is well documented in the earliest investigations of fistulas and they continue to be helpful techniques. The imaging techniques have evolved rapidly over the past 15 years with the introduction of cross-sectional imaging, ultrasound and endoscopy. The purpose of this chapter is to review both the diagnostic and therapeutic roles of fistulograms, small bowel follow-through, computed tomography, magnetic resonance imaging, ultrasound, and endoscopy in the setting of acquired enterocutaneous fistulas.

High-output fistula

Despite improvements in healthcare delivery, mortality rates for high-output fistulae remain unchanged. The pathophysiology and causes of fistulae are reviewed in this article. An overview of the diagnostic procedures to delineate fistulae and underlying bowel disease together with their complications is included. Management of high-output fistulae consists of assessment and stabilization of patients, followed by conservative management by a multidisciplinary team until spontaneous or surgical closure of fistulae.

Current considerations in the management of rectovaginal fistula from Crohn's disease

Rectovaginal fistulas are dreaded complications of Crohn's disease. Accurate assessment is essential for planning management. Treatment options range from observation to medical therapeutics to the need for surgical intervention. Ultimately, establishing reasonable expectations is mandatory when treatment algorithms are considered. In this article, we review the evaluation of these fistulas and the current options to consider in the treatment of Crohn's related rectovaginal fistula.

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.

Postoperative enterocutaneous fistula: when to reoperate and how to succeed

An enterocutaneous fistula (ECF) is a potentially catastrophic postoperative complication. Although the morbidity and mortality associated with ECF have decreased over the past 50 years with modern medical and surgical care, the overall mortality is still surprisingly high, up to 39% in recent literature. It seems prudent, then, for every surgeon to have a thorough grasp of optimal treatment strategies for ECF to minimize their patients' mortality. Ultimately, the algorithm must begin with prevention. Once an ECF is diagnosed, the first step is to resuscitate and treat sepsis. The second is to control fistula output. The third step is to optimize the patient medically and nutritionally. The last step is definitive restoration of gastrointestinal continuity when necessary. Special mention is given in this article to exceptionally refractory fistulas such as those arising in the presence of inflammatory bowel disease and irradiated bowel. This plan gives a framework for the difficult task of successfully treating the postoperative ECF with a multidisciplinary approach.

Bowel ultrasound in Crohn's disease

Most published studies have found bowel ultrasound to be a useful tool in the management of Crohn's disease. Indeed, it has been successfully used as the imaging technique of choice in screening patients with clinically suspected Crohn's disease. In these patients, bowel ultrasound, which is well accepted by patients, non-invasive and of low cost, may be the first diagnostic tool employed for young patients and can be used in the preliminary diagnostic work-up prior to further invasive tests. The most important application of bowel ultrasound is, however, in the follow-up of patients already diagnosed with Crohn's disease, in whom it may be useful to assess the site and extent of the lesions and to ensure the early detection of intra-abdominal complications, particularly abscesses and strictures. In this regard, improving the ultrasound assessment of intramural blood flow by means of colour power-Doppler ultrasonography and intravenous contrast agents may help to differentiate fibrotic and inflammatory strictures, and to discriminate inflammatory masses from intra-abdominal abscesses. Despite several attempts to correlate ultrasound findings with clinical and biochemical activity, there are as yet no convincing data on the usefulness of ultrasound in assessing the activity of Crohn's disease. In contrast, preliminary results are in agreement regarding the usefulness of ultrasound in the assessment of postoperative recurrence and in monitoring the outcome of the disease following surgery. In fact, the persistence of a thickened bowel wall or increased high bowel wall thickening at ultrasound following surgery has been identified as an index of early surgical recurrence. How these data may be usefully employed in the management of individuals with Crohn's disease needs to be investigated in further studies.

A new semiquantitative method of quantifying Helicobacter pylori in antigen stools

Stool antigen test for Helicobacter pylori, a noninvasive assay, is emerging as a strong competitor to urea breath test (UBT). Nevertheless, although the UBT delta value is a semiquantitative indicator of H. pylori intragastric load, until now the H. pylori stool antigen test has been used only as a qualitative investigation. We report here the results of a study performed with the aim of obtaining a semiquantitative measurement of bacterial amount in stools. We studied 15 patients with dyspepsia using H. pylori positivity at histology, the rapid urease test, UBT, and the H. pylori stool antigen test. The result of this last test was expressed by a numerical value we obtained by applying the principle of "standard points" to the absorbance units at spectrophotometric reading. This measurement was previously validated by testing probe sampling of H. pylori stool antigen with known pure and stool-mixed bacterial amounts. A numerical result for H. pylori stool antigen was correlated to UBT delta for each patient using Pearson's r test. Finally, a Student t test was performed to investigate possible differences in UBT and H. pylori stool antigen test values between anti-CagA-positive and -negative patients. We obtained a curve of saturation with both known amount of pure and stool-mixed bacteria. Pearson's r test showed a significant correlation between UBT delta value and H. pylori stool antigen measurement (r = 0.77; p < 0.001). Urea breath test delta and H. pylori stool antigen test values were significantly higher in anti-CagA-positive patients. Our data suggest that a numerical estimation of H. pylori stool antigen may be feasible. This evaluation, similarly to UBT delta, may represent a semiquantitative determination of bacterial intragastric load.

Acquired gastrointestinal fistulas: classification, etiologies, and imaging evaluation

Fistulas are abnormal communications between two epithelial-lined surfaces. Gastrointestinal fistulas encompass all such connections that involve the alimentary tract, and they can be congenital or acquired in nature. This review focuses on acquired gastrointestinal fistulas. Development of an acquired gastrointestinal fistula can greatly affect patient outcome, yet the clinical manifestations are often protean in nature and the etiology, elusive. Imaging plays an important role in the detection and management of acquired gastrointestinal fistulas. The more routine use of cross-sectional imaging (especially computed tomography and magnetic resonance imaging) has altered the standard sequence of radiologic evaluation for possible fistulas, but fluoroscopic studies remain a valuable complement, especially for confirming and defining the anomalous communications. In this review, a classification scheme for gastrointestinal fistulas is provided, major causes are discussed, and individual fistula types are elaborated with an emphasis on contemporary imaging approaches.