1. Aetna considers endoscopic ultrasonography (EUS) medically necessary for any of the following indications:
   1. Evaluating abnormalities of the biliary tree; or
   2. Evaluating abnormalities of the gastrointestinal tract wall or adjacent structures; or
   3. Evaluating abnormalities of the pancreas, including masses, pseudocysts and chronic pancreatitis; or
   4. Evaluating adenopathy and masses of the posterior mediastinum (endoscopic ultrasonography with fine-needle aspiration); or
   5. Pre-operative staging of gastric cancer; or
   6. Providing endoscopic therapy under ultrasonographic guidance; or
   7. Sampling tissue of lesions within, or adjacent to, the wall of the gastrointestinal tract; or
   8. Staging of lung cancer (endoscopic ultrasonography with fine-needle aspiration); or
   9. Staging tumors of the gastrointestinal tract (including the esophagus, the stomach), pancreas and bile ducts; or 
   10. Surveillance of certain gastric subepithelial masses (asymptomatic glomus tumors or small (less than 3 cm) gastrointestinal stromal tumors).

2. Aetna considers EUS experimental and investigational for all other indications because of insufficient evidence in the peer-reviewed literature, including the following conditions:
   1. EUS-elastography (for differential diagnosis of malignant lymph nodes); and 
   2. For staging of tumors shown to be metastatic by other imaging methods (unless the results are the basis for therapeutic decisions); and  
   3. When the results will not alter care of the member.

Endoscopic ultrasonography (EUS) incorporates high-frequency ultrasound into the tip of the endoscope to visualize the gastrointestinal wall and surrounding structures.  Using endoscopy, ultrasound probes can be placed in close proximity to the target anatomy, thereby enhancing resolution of the gastrointestinal wall and adjacent structures.  Tissue samples can be obtained and therapy can be performed by passing instruments under ultrasonographic guidance.

Endoscopic ultrasonography is used for staging tumors of the gastrointestinal tract, pancreas and bile ducts; the most notable application is in staging esophageal, gastric, and rectal tumors.  Studies show that EUS is the most accurate imaging modality for staging depth of tumor invasion, with pre-operative accuracy in the 80 % to 90 % range when compared with surgical pathology.  However, biopsy and histopathologic evaluation are needed to identify the specific histology.  Endoscopic ultrasonography can not reliably distinguish an inflammatory process from a neoplastic process.  In addition, EUS has proved less accurate in staging lymph node than in staging depth of tumor invasion because the node has to be located and then identified as benign or malignant.

A recent advance of EUS is high-frequency ultrasound probe sonography (HFUPS).  This has been researched as a method of providing ultrasound imaging of visible lesions without endoscope exchange as it can be performed through the biopsy channel of an endoscope.  Two commercially available probes, the Olympus UM-2R/UM-3R Ultrasonic Probes (Olympus Optical Co.) and the Fujinon Sonoprobe SP-701 (Fujinon, Inc.), have received 510(k) status from the Food and Drug Administration.  High-frequency ultrasound probe sonography has been used in the staging of esophageal, gastric, ampullary, pancreatobiliary, and colonic neoplasms; however, there is limited information on the clinical impact of HFUPS.  The American Society for Gastrointestinal Endoscopy (ASGE) reviewed the medical literature on HFUPS and concluded that HFUPS can provide detailed imaging of the gastrointestinal wall for the evaluation and staging of mucosal and submucosal lesions of the gastrointestinal tract and pancreatico-biliary tree.  It may also provide useful information that could affect therapeutic strategies in patients with superficial lesions; however, the technique should be reserved for use by centers with significant experience in EUS.  In addition, further studies on the clinical impact of HFUPS are necessary.

Endoscopic ultrasonography has been proven a reliable and accurate diagnostic tool for staging tumors of the gastrointestinal tract, pancreas and bile ducts; evaluating abnormalities of the gastrointestinal tract wall or adjacent structures; tissue sampling of lesions within, or adjacent to, the wall of the gastrointestinal tract; evaluation of abnormalities of the pancreas, including masses, pseudocysts and chronic pancreatitis; evaluation of abnormalities of the biliary tree; and providing endoscopic therapy under ultrasonographic guidance.  These indications for EUS were supported by the guidelines on the Appropriate Use of Gastrointestinal Endoscopy (1997) developed by the ASGE with the assistance and support of the American Gastroenterological Association, the American College of Gastroenterology, the Society for Surgery of the Alimentary Tract, the Society of American Gastrointestinal Endoscopic Surgeons, and the American Society for Colon and Rectal Surgery.

Sreenarasimhaiah (2005) stated that the emergence of EUS has given promise to improved staging with its 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 demonstrated superior accuracy in staging with EUS and EUS-FNA for tumors of the esophagus, stomach, pancreas, rectum, and mediastinum, including lung cancer.  This is in agreement with previous findings. 

Guidelines from the ASGE (Jacobson et al, 2003) concluded that EUS-FNA is indicated for the evaluation of adenopathy and masses of the posterior mediastinum.  The guidelijnes state that it is the procedure-of-choice for tissue sampling of such lesions in the subcarinal, subaortic (aorto-pulmonary window), and peri-esophageal stations found on cross-sectional imaging.  The guidelines state that EUS-FNA should also be considered in the pre-operative staging of patients with non-small cell lung cancer without definite adenopathy on cross-sectional imaging.

The medical position on the management of patients with gastric subepithelial masses from the American Gastroenterological Association Institute (Hwang and Kimmey, 2006) noted that patients with symptoms that can be attributed to the mass should undergo endoscopic or surgical resection of the mass.  Current evidence does not allow making a firm recommendation on the optimal management of the patient with an incidentally detected, asymptomatic gastric subepithelial mass.  Options include performing no further testing or monitoring, following the mass with periodic endoscopic or EUS surveillance, and endoscopic or surgical resection of the mass.  These management options should be discussed with the patient and whenever possible guided by EUS imaging and tissue sampling information, because the clinical significance of the mass is highly variable.  This guideline recommended EUS surveillance for asymtomatic patients with glomus tumor or gastrointestinal stromal tumor that is less than 3 cm in diameter.

In a meta-analysis and systematic review, Puli et al (2009) evaluated the accuracy of EUS in diagnosing nodal metastasis of rectal cancers.  The authors concluded that the sensitivity and specificity of EUS is moderate.  They stated that further refinement in EUS technologies and diagnostic criteria are needed to improve the diagnostic accuracy.

Shirakawa et al (2004) noted that peripheral lung lesions are increasing in numbers.  Since conventional diagnostic procedures have limitations in availability and results, endoscopic diagnosis is essential for the prevention of unnecessary operations.  The authors concluded that: when the lesion can be correctly described by endobronchial ultrasonography from inside the lesion, endobronchial ultrasonography is useful to guide transbronchial lung biopsy, can contribute to a reduction in patient discomfort and improves the accuracy of diagnosis.  Kramer and colleagues (2004) concluded that EUS-FNA can replace more than half of the surgical staging procedures in lung cancer patients with mediastinal and/or upper retroperitoneal positron emission tomography hot spots, thereby saving 40 % of staging costs.

The Canadian Agency for Drugs and Technologies in Health's report on endobronchial ultrasound (EBUS) for lung cancer diagnosis and staging (Ho et al, 2009) noted that EBUS is a new technology that involves the introduction of an ultrasound probe into the thoracic region via the bronchial airway while patients are under conscious sedation or general anesthesia.  The probe is used to generate images of pulmonary and mediastinal structures.  Its use allows minimally invasive sampling of peripheral pulmonary lesions, and mediastinal and hilar lesions.  The development of the built-in linear probe, as opposed to a radial probe, enables real time guidance during EBUS-transbronchial needle aspiration (EBUS-TBNA).  These investigators reviewed published literature by cross-searching Embase and Medline databases between 2004 and April 2009.  Parallel searches were performed on PubMed and The Cochrane Library (Issue 1, 2009) databases.  The websites of regulatory agencies, and health technology assessment and related agencies, were searched, as were specialized databases.  The Google search engine was used to search for information on the Internet.

These researchers identified 1 health technology assessment (HTA), 1 meta-analysis, 2 cost analyses, and 3 observational studies on the use of EBUS for lung cancer diagnosis and staging.  The HTA examined the safety and effectiveness of EBUS for detection and staging in patients with suspected or established lung cancer.  No meta-analysis was performed, and the conclusions that were presented came from individual trials.  The HTA found a statistically significantly increased diagnostic yield for mediastinal lymph nodes when EBUS-TBNA was compared to conventional TBNA.  In the 2009 meta-analysis, the overall diagnostic accuracy of EBUS-TBNA in detecting metastatic mediastinal lymph nodes in patients who were suspected of having lung cancer was assessed.  Endobronchial ultrasound-guided transbronchial needle aspiration had a pooled sensitivity of 0.93 (95 % confidence interval [CI]: 0.91 to 0.94) and a pooled specificity of 1.00 (95 % CI: 0.99 to 1.00) for lung cancer detection and staging.  When compared directly, EBUS-TBNA was found to be more sensitive than conventional TBNA.  The findings from recent trials were in agreement with the findings of the meta-analysis on EBUS-TBNA diagnostic accuracy.  The authors concluded that based on the existing evidence, EBUS is an accurate and safe tool for use in lung cancer diagnosis and staging.

In a systematic review on the safety and effectiveness of EBUS-TBNA, Varela-Lema et al (2009) reviewed a total of 20 publications.  Of these, 14 were original studies that examined the clinical usefulness of the technique in visualizing and staging lymph nodes in patients with suspected or established lung cancer.  Sensitivity ranged 85 % to 100 % and negative predictive value ranged 11 % to 97.4 %.  Three studies evaluated the clinical usefulness of the technique in the diagnosis of sarcoidosis.  EBUS-TBNA was diagnostic in 88 % to 93 % of patients.  One retrospective study evaluated the use of EBUS-TBNA in the diagnosis of lymphoma.  None of the studies included in the present review reported important complications.  Endobronchial ultrasound-guided transbronchial needle aspiration is a safe and highly accurate procedure for the examination and staging of mediastinal and hilar lymph nodes in patients with known or suspected lung malignancy.  The evidence is promising for sarcoidosis but is insufficient for lymphoma.

Adams et al (2009) carried out a systematic review of published studies evaluating EBUS-TBNA for mediastinal lymph node staging to ascertain the pooled sensitivity and specificity of this investigation.  A literature search was constructed and performed by a professional medical librarian to identify the literature from 1960 to February 2008.  Pooled specificity and sensitivity was estimated from the extracted data with an exact binomial rendition of the bivariate mixed-effects regression model.  Of 365 publications, 25 were identified in which EBUS-TBNA was specifically focused on mediastinal node staging.  Of these, only 10 had data suitable for extraction and analysis.  The overall test performance was excellent with an area under the summary receiver operating characteristics curve of 0.99 (95 % CI: 0.96 to 1.00); similarly, EBUS-TBNA had excellent pooled specificity of 1.00 (95 % CI: 0.92 to 1.00) and good pooled sensitivity of 0.88 (95 % CI: 0.79 to 0.94).  The authors concluded that EBUS-TBNA has excellent overall test performance and specificity for mediastinal lymph node staging in patients with lung cancer.  The results compare favorably with published results for computed tomography (CT) and positron emission tomography.

Cameron and colleagues (2010) stated that EBUS-TBNA is a recently developed, accurate, safe and cost-effective technique that allows sampling of mediastinal lymph nodes and peri-bronchial lesions including pulmonary and mediastinal lesions.  Its major indications are the nodal staging of non-small cell carcinomas of the lung, their re-staging following chemotherapy and/or radiation, the diagnosis of sarcoidosis and of metastases from extra-thoracic malignancies, and the diagnosis of mediastinal lymphadenopathy and masses of unknown etiology.

In a pilot study, Aumiller et al (2009) examined the feasibility of detecting pulmonary embolism (PE) in the central airways by EBUS.  Consecutive patients underwent flexible bronchoscopy with a convex EBUS probe under local anesthesia and moderate sedation within 24 hrs after angio-CT had documented a central PE.  The EBUS images were compared to the CT findings.  Among 32 patients (mean age of 69 years, 20 men), angio-CT documented 101 PE, of which 97 (96 %) were also detected with EBUS.  The 4 emboli not detected consisted of 1 in a middle lobe and 3 in a left upper lobe artery.  At least 1 embolus was detected with EBUS in every patient, which is sufficient to confirm a diagnosis of central PE.  No bronchoscopic complications were observed.  Mean procedure time was reduced from 5 mins in the first 16 patients to 3 mins in the last 16.  The authors concluded that EBUS was a feasible and safe approach to detecting central pulmonary emboli.  Moreover, they stated that blinded, comparative trials are needed to evaluate its use as a primary tool for diagnosing these emboli.

Soja et al (2009) examined the use of EBUS for the assessment of bronchial wall remodeling in patients with asthma.  In 35 patients with asthma and 23 control subjects, high-resolution CT (HRCT) scanning and EBUS were used to measure bronchial wall thickness in the 10th segment of the right lung.  With a radial 20-MHz probe, EBUS identified the 5-laminar structure of the bronchial wall.  Layer 1 (L(1)) and layer 2 (L(2)) were analyzed separately, and layers 3 through 5 (L(3-5)), which corresponded to cartilage, were analyzed jointly.  Digitalized EBUS images were used for the quantitative assessment of bronchial wall thickness and the wall area (WA) of the layers.  Finally, bronchial biopsy specimens were taken for measuring the thickness of the reticular basement membrane (RBM).  The thickness and WA of the bronchial wall layers, which were assessed using EBUS, were correlated with FEV(1) and RBM.  There was no significant difference in the measurements of total bronchial wall thickness using EBUS and HRCT scanning.  The thickness and WA of the bronchial wall and its layers were significantly greater in patients with asthma than in the control subjects.  A negative correlation among the thicknesses of L(1), L(2), and L(3-5) and FEV(1), and a positive correlation with RBM were observed only in the patients with asthma.  The authors concluded that EBUS allows precise measurement of the thickness and WA of bronchial wall layers.  The correlation of these parameters with asthma severity suggested implementation of EBUS in the assessment of bronchial wall remodeling in patients with asthma.

In a meta-analysis, Wu et al (2011) evaluated the accuracy of EUS elastography by pooling data of existing trials.  A total of 7 studies involving 368 patients with 431 lymph nodes (LNs) were included.  Pooling was conducted in a fixed-effect model or a random-effect model.  The pooled sensitivity of EUS elastography for the differential diagnosis of benign and malignant LNs was 88 % (95 % CI: 0.83 to 0.92), and the specificity was 85 % (95 % CI: 0.79 to 0.89).  The area under the curve under summary receiver operating characteristic (SROC) was 0.9456.  The pooled positive likelihood ratio was 5.68 (95 % CI: 2.86 to 11.28), and the negative likelihood ratio was 0.15 (95 % CI: 0.10 to 0.21).  The subgroup analysis by excluding the outliers provided a sensitivity of 85 % (95 % CI: 0.79 to 0.90) and a specificity of 91 % (95 % CI: 0.85 to 0.95) for the differential diagnosis of benign and malignant LNs.  The area under the curve under SROC was 0.9421.  The authors concluded that EUS elastography is a promising, non-invasive method for differential diagnosis of malignant LNs and may prove to be a valuable supplemental method to EUS-guided FNA.

Will and Meyer (2012) stated that endoscopic retrograde cholangiopancreatography (ERCP) and percutaneous transhepatic cholangiography (PTC) are considered the gold standard in the interventional treatment of biliary obstruction, in particular, with palliative intention.  If ERCP and PTC are not possible, an alternative drainage procedure such as the endoscopic ultrasound-guided cholangiodrainage (EUCD) can be used.  Endoscopic US-guided cholangiodrainage is an endoscopic/sonografic procedure, which is used in case of post-operatively changed anatomy of the upper gastro-intestinal tract (BII gastric resection, pylorus-preserving pancreas head resection, Whipple procedure, [sub-]total gastrectomy, Roux-en-Y reconstruction) and, thus, if papilla of Vater (papilla) can not be reached or catheterized or if the patient denies PTC; and in subjects with recurrent, advanced or metastasized tumor lesion(s) of the upper abdomen, hepatobiliary system as well as pancreas and associated obstruction of the biliary tree/jaundice.  The authors stated that with regard to the limited diffusion process, EUCD can not be considered a standard procedure yet.  The advantages comprise low tissue trauma, primary internal drainage and the possible endoscopic re-intervention in case of complications.  The high technical challenge in performing EUCD is an unfavorable aspect for broader use in clinical practice.  However, the disclosed treatment results demonstrating an acceptable complication rate show that EUCD can be competitively considered to ERCP und PTC with a great chance for primary success.  These investigatros concluded that EUCD is an elegant, not yet fully established, but rather still experimental procedure of interventional endoscopy/EUS, which needs great expertise of the endoscopist in an inter-disciplinary center of visceral medicine as one of the main predictions.  In experienced hands, a safe procedure can be provided, for which a systematic follow-up and a multi-center evaluation of peri-interventional management are still needed in order to achieve a final assessment of EUCD for guideline approval.

Cardoso et al (2012) stated that accurate pre-operative staging is important in determining the appropriate treatment of gastric cancer.  Recently, EUS has been introduced as a staging modality.  However, reported test characteristics for EUS in gastric cancer vary.  These investigators identified, synthesized, and evaluated findings from all articles on the performance of EUS in the pre-operative staging of gastric cancer.  Electronic literature searches were conducted using Medline, Embase, and the Cochrane Central Register of Controlled Trials from January 1, 1998 to December 1, 2009.  All search titles and abstracts were independently rated for relevance by a minimum of 2 reviewers.  Meta-analysis for the performance of EUS was analyzed by calculating agreement (Kappa statistic), and pooled estimates of accuracy, sensitivity, and specificity for all EUS examinations, using histopathology as the reference standard. Subgroup analyses were also performed.  A total of 22 articles met inclusion criteria and were included in the review.  Endoscopic ultrasonography pooled accuracy for T staging was 75 % with a moderate Kappa (0.52); EUS was most accurate for T3 disease, followed by T4, T1, and T2.  Endoscopic ultrasonography pooled accuracy for N staging was 64 %, sensitivity was 74 %, and specificity was 80 %.  There was significant heterogeneity between the included studies.  Subgroup analyses found that annual EUS volume was not associated with EUS T and N staging accuracy (p = 0.836, 0.99, respectively).  The authors concluded that EUS is a moderately accurate technique that seems to describe advanced T stage (T3 and T4) better than N or less advanced T stage.  Stratifying by EUS annual volume did not affect EUS performance in staging gastric cancer.

The National Comprehensive Cancer Network’s clinical practice  guideline on gastric cancers (including cancer in the proximal 5 cm of the stomach) (NCCN, 2013) states that “clinical staging has greatly improved with the availability of diagnostic modalities such as endoscopic ultrasound (EUS) …. EUS performed prior to any treatment is important in the initial clinical staging of gastric cancer …. This is especially important in patients who are being considered for EMR [endoscopic mucosal resection]”.