Gastrointestinal endoscopic ultrasonography

Endoscopic ultrasound in oncology: An update of clinical applications in the gastrointestinal tract

An accurate staging is necessary to select the best treatment and evaluate prognosis in oncology. Staging usually begins with noninvasive imaging such as computed tomography, magnetic resonance imaging or positron emission tomography. In the absence of distant metastases, endoscopic ultrasound plays an important role in the diagnosis and staging of gastrointestinal tumors, being the most accurate modality for local-regional staging. Its use for tumor and nodal involvement in pre-surgical evaluation has proven to reduce unnecessary surgeries. The aim of this article is to review the current role of endoscopic ultrasound in the diagnosis and staging of esophageal, gastric and colorectal cancer.

Predictive features for histology of gastric subepithelial lesions

BACKGROUND

- Gastric subepithelial lesion is a relatively common diagnosis after routine upper endoscopy. The diagnostic workup of an undetermined gastric subepithelial lesion should take into consideration clinical and endoscopic features.

OBJECTIVE

- We aimed to investigate the association between patients' characteristics, endoscopic and echographic features with the histologic diagnosis of the gastric subepithelial lesions.

METHODS

- This is a retrospective study with 55 patients, who were consecutively diagnosed with gastric subepithelial lesions, from October 2008 to August 2011. Patients' characteristics, endoscopic and echografic features of each gastric subepithelial lesion were analysed. Histologic diagnosis provided by EUS-guided fine needle aspiration or endoscopic/surgical resection was used as gold standard.

RESULTS

- The probability of gastrointestinal stromal tumors to be located in the cardia was low (4.5%), while for leiomyoma it was high (>95%). In addition, there was a higher risk of gastrointestinal stromal tumors in patients older than 57 years (OR 8.9; 95% CI), with lesions ≥21 mm (OR 7.15; 95% CI), located at 4th layer (OR 18.8; 95% CI), with positive Doppler sign (OR 9; 95% CI), and irregular outer border (OR 7.75; 95% CI).

CONCLUSION

- The location of gastric subepithelial lesions in the gastric cardia lowers the risk of gastrointestinal stromal tumors. While gastric subepithelial lesions occurring in elderly patients, located in the gastric body, with positive Doppler signal and irregular outer border increase the risk of gastrointestinal stromal tumors.

Polypyrrole hollow microspheres as echogenic photothermal agent for ultrasound imaging guided tumor ablation

Ultrasound (US) imaging provides a valuable opportunity to administer photothermal therapy (PTT) of cancer with real-time guidance to ensure proper targeting, but only a few theranostic agents were developed by physically grafting near infrared (NIR)-absorbing inorganic nanomaterials to ready-made ultrasound contrast agents (UCAs) for US imaging guided PTT. In this paper, NIR absorbing hollow microspheres were generated from polypyrrole merely using a facile one-step microemulsion method. It was found that the obtained polypyrrole hollow microspheres (PPyHMs) can act as an efficient theranostic agent not only to enhance US imaging greatly, but also exhibit excellent photohyperthermic effects. The contrast consistently sustained the echo signals for no less than 5 min and the NIR laser light ablated the tumor completely within two weeks in the presence of PPyHMs. More importantly, no use of additional NIR absorber substantially minimizes an onetime dose of the theranostic agent.

Pathophysiology, clinical presentation, and management of colon cancer

Colon cancer is believed to arise from two types of precursor polyps via two distinct pathways: conventional adenomas by the conventional adenoma-to-carcinoma sequence and serrated adenomas according to the serrated adenoma-to-carcinoma theory. Conventional adenomas arise from mutation of the APC gene; progression to colon cancer is a multistep process. The fundamental genetic defect in serrated adenomas is unknown. Environmental factors can increase the risk for colon cancer. Advanced colon cancer often presents with symptoms, but early colon cancer and premalignant adenomatous polyps commonly are asymptomatic, rendering them difficult to detect and providing the rationale for mass screening of adults over age 50.

Endoscopic ultrasonography in the diagnosis and management of cancer

Since its development and introduction to clinical practice, endoscopic ultrasonography (EUS) has progressed rapidly from being a purely imaging modality with limited use in the detection of small pancreatic cancers to one that can provide a tissue diagnosis by fine-needle aspiration (FNA) and deliver therapy. EUS has now firmly established a place as the investigation of choice in the diagnosis, locoregional staging and management of a wide range of gastrointestinal cancers. With the increasing use of FNA, the accuracy of EUS has substantially improved and may become a stand-alone investigation in some situations. However, it is recommended that a combination of information obtained from other imaging modalities and EUS is needed to maximize the accuracy, in particular to complete staging beyond locoregional stage. In addition to well-established indications, newer applications of EUS are emerging and are no longer limited to the gastrointestinal system. In lung cancer, EUS combined with endobronchial ultrasonography is emerging as an accurate, minimally invasive, nonsurgical alternative to staging of the mediastinum. Furthermore, the ability of EUS to acquire tissue safely and conveniently results in a potential role of the molecular diagnostics to enhance the performance of EUS-guided FNA. Besides a diagnostic role of EUS, there continues to be technological advances in the field of interventional EUS, with many potential applications under investigation. This review focuses on the current and future roles of EUS in the diagnosis and management of cancers.

Imaging of various gastric lesions with 2D MPR and CT gastrography performed with multidetector CT

Recent advances in computed tomographic (CT) technology, three-dimensional imaging software, and cheaper data storage capacity have made faster, simpler, and more accurate gastric imaging available. Two-dimensional multiplanar reformation and CT gastrography including virtual gastroscopy and transparency rendering allow multiplanar cross-sectional imaging, gastroscopic viewing, and upper gastrointestinal series imaging in the same data acquisition. Multi-detector row CT allows noninvasive assessment of the gastric wall and the perigastric extent of disease. It is also helpful in detection and evaluation of gastric malignancies and a variety of inflammatory conditions that affect the stomach. Conventional gastroscopy provides the most useful information about the exact location of the lesion and also allows performance of biopsy. Endoscopic ultrasonography (US) provides the most useful information about horizontal extension of the tumor, the depth of mural invasion, and perigastric lymphadenopathy. However, endoscopic US has not been able to replace CT for tumor staging because of its limitations in demonstrating distant lymphadenopathy or metastatic deposits.

The emerging role of endoscopic ultrasonography in cancer staging

The management of solid organ cancers relies on accurate staging. Once distal metastasis has been excluded by conventional radiographic methods, local staging of the tumor and its nodal involvement is essential to determine the most optimal therapeutic approach. Many radiographic imaging modalities are unable to determine subtle tumor involvement. However, the emergence of endoscopic ultrasonography (EUS) has given promise to improved staging with its unique ability to examine tumors from within the gastrointestinal lumen with extremely close proximity. An additional advantage is the ability to perform fine-needle aspiration (FNA) biopsy to confirm or exclude tumor involvement. Many studies have shown superior accuracy in staging with EUS and EUS-FNA for tumors of the esophagus, stomach, pancreas, rectum, and mediastinum, including lung cancer. This review illustrates the principles of EUS and its role in staging of a variety of cancers and particularly its role alongside other imaging modalities.

Clinical presentation, diagnosis, and management of gastroesophageal reflux disease

GERD is ubiquitous throughout the adult population in the United States. It commonly adversely affects quality of life and occasionally causes life-threatening complications. The new and emerging medical and endoscopic therapies for GERD and the new management strategies for BE should dramatically reduce the clinical toll of this disease on society.

From Colonic Polyps to Colon Cancer: Pathophysiology, Clinical Presentation, and Diagnosis

Epidemiologists, basic researchers, clinicians, and public health administrators unite! Develop and implement a simple, safe, and effective preventive and screening test for colon cancer. The public will willingly and enthusiastically accept such a test. Many thousands of lives are at stake every year.

The pathophysiology, clinical presentation, and diagnosis of colon cancer and adenomatous polyps

A review of the pathophysiology, clinical presentation, and diagnosis of colon cancer and colonic polyps is important and timely. This field is rapidly changing because of breakthroughs in the molecular basis of carcinogenesis and in the technology for colon cancer detection and treatment. This article reviews colon cancer and colonic polyps, with a focus on recent dramatic advances, to help the pri-mary care physician and internist appropriately refer patients for screening colonoscopy and intelligently evaluate colonoscopic findings to reduce the mortality from this cancer.

Individual variations in mucosa and total wall thickness in the stomach and rectum assessed via endoscopic ultrasound

Endoscopic ultrasound is a unique tool to acquire in vivo data on alimentary tract wall thicknesses of sufficient resolution needed in radiation dosimetry studies. Through their different echo texture and intensity, five layers of differing echo patterns for superficial mucosa, deep mucosa, submucosa, muscularis externa and serosa/adventitia exist within the walls of organs composing the alimentary tract. In this study, retrospective image analyses of patient video data were made for ten examinations of the stomach and eight examinations of the rectum covering a range of patient ages. Thicknesses for stomach mucosa ranged from 1030 +/- 130 microm to 1640 +/- 80 microm (total stomach wall thicknesses from 2.80 +/- 0.12 to 4.23 +/- 0.03 mm). Measurements made for the rectal images revealed rectal mucosal thicknesses from 660 +/- 50 microm to 1130 +/- 250 microm (total rectal wall thicknesses from 2.28 +/- 0.05 to 3.55 +/- 0.43 mm). The mucosa accounted for approximately 32 +/- 7% and approximately 32 +/- 8% of the total thickness of the stomach and rectal wall, respectively. These values can thus be utilized to investigate uncertainties in alimentary tract dosimetry that are based upon fixed reference individual definitions of organ wall structure.

Barrett's esophagus: current and future role of endosonography and optical coherence tomography

This paper reviews the role of endosonography and optical coherence tomography (OCT) for imaging of Barrett's esophagus (BE). The routine use of endoscopic ultrasound (EUS) to screen patients with BE is neither justified nor cost effective. EUS does appear to have a role in patients who have BE and high-grade dysplasia or intramucosal carcinoma, in whom a non-operative therapy is being contemplated. For patients with a diagnosis of esophageal cancer with or without BE, EUS is superior to computed tomography or magnetic resonance imaging for assessing esophageal wall penetration and for detecting regional lymph node involvement. In its current state, OCT is not yet ready for application in clinical practice. However, given its superior resolution compared with other modalities such as EUS, OCT has great potential as a powerful adjunct to standard endoscopy in surveillance of BE and may enhance the ability of endoscopists to detect high-grade dysplasia at an early stage. With further technical refinement, this technique may become a mainstay in the surveillance of BE and other premalignant conditions of the gastrointestinal tract.