Pre- and post-training session evaluation for interobserver agreement and diagnostic accuracy of probe-based confocal laser endomicroscopy for biliary strictures.

BACKGROUND AND AIM: Current diagnostic modalities for indeterminate biliary strictures offer low accuracy. Probe-based confocal laser endomicroscopy (pCLE) permits microscopic assessment of mucosal structures by obtaining real-time high-resolution images of the mucosal layers of the gastrointestinal tract. Previously, an interobserver study demonstrated poor to fair agreement even among experienced confocal endomicroscopy operators. Our objective was to assess interobserver agreement and diagnostic accuracy upon completion of a pCLE training session. METHODS: Forty de-identified pCLE video clips of indeterminate biliary strictures were sent to five endoscopists at four tertiary care centers for scoring. Observers subsequently attended a teaching session by an expert pCLE user that included 20 training clips and rescored the same pCLE video clips, which were randomized and renumbered. RESULTS: Pre-training interobserver agreement for all observers was 'fair' (Κ: 0.31, P-value: <0.0001) and diagnostic accuracy was 72% (55-80%). Post-training interobserver agreement for all observers was 'substantial' (Κ: 0.74, P-value: <0.0001) and diagnostic accuracy was 89% (80-95%). Using a paired t-test, we observed an increase of 17% (95% CI 7.6-26.4) in post-training diagnostic accuracy (t = 5.01, df = 4, P-value 0.007). CONCLUSIONS: Interobserver agreement and diagnostic accuracy improved after observers underwent training by an expert pCLE user with a specific sequence set. Users should participate in such training programs to maximize diagnostic accuracy of pCLE evaluation.

Interobserver agreement for confocal imaging of ampullary lesions: a multicenter single-blinded study.

BACKGROUND: Malignant ampullary lesions can be difficult to classify by endoscopy alone. Probe-based confocal laser endomicroscopy (pCLE) permits in vivo assessment of mucosal structures in the gastrointestinal tracts in the real time. AIM: The objective of this pilot multicenter study was to assess the interobserver agreement and variance in interpretation of pCLE of ampullary lesions. METHODS: Twelve pCLE video clips of ampullary lesions were distributed to 6 gastrointestinal specialists at 5 medical centers, blinded to final pathologic results. Six variables were assessed for interobserver agreement using κ statistics. Variables included an epithelial outer border with irregular thickness, dark epithelium without discernable individual cells, heterogenously distributed elongated crypts, reduced number of goblet cells, neovascularization, and final diagnosis. RESULTS: The overall interobserver agreement for all observers was poor to slight for all variables (κ=0.02, 0.05, -0.01, 0.04, 0.018) except for the first variable with fair degree of agreement (κ=0.27). On the basis of experience, 3 observers were classified as less experienced, whereas 3 were classified as most experienced. Upon stratification, the less experienced observers had poor interobserver agreement for all variables, except 1. The most experienced observers had poor agreement for 2 variables, slight agreement for 3 variables, and fair agreement for the final diagnosis variable. CONCLUSIONS: The overall interpersonal agreement on pCLE for ampullary lesions was poor. The interobserver agreement was not substantially improved for experienced raters. Further standardization of pCLE image criteria is needed for ampullary lesions. Standardized training may improve interrater reliability to an acceptable level.

Multicenter trial evaluating the use of covered self-expanding metal stents in benign biliary strictures: time to revisit our therapeutic options?

BACKGROUND: Covered self-expanding metal stents are being used more frequently in benign biliary strictures (BBS). We report the results of a multicenter study with fully covered self-expanding metal stent (FCSEMS) placement for the management of BBS. AIM: : To prospectively evaluate the efficacy and safety of FCSEMS in the management of BBS. PATIENTS AND METHODS: Patients with BBS from 6 tertiary care centers who received FCSEMS with flared ends between April 2009 and October 2010 were included in this retrospective study.Efficacy was measured after removal of FCSEMS by evaluating stricture resolution on the basis of symptom resolution, imaging, laboratory studies, and/or choledochoscopy at removal. Safety profile was evaluated by assessing postprocedural complications. RESULTS: A total of 133 patients (78, 58.6% males) with a mean age of 59.2±14.8 years with BBS received stents. Of the 133 stents placed, 97 (72.9%) were removed after a mean stent duration of 95.5±48.7 days. Stricture resolution after FCSEMS removal was as follows: postsurgical, 11/12 (91.6%); gallstone-related disease, 16/19 (84.2%); chronic pancreatitis, 26/31 (80.7%); other etiology, 4/5 (80.0%); and anastomotic strictures, 19/31(61.2%). Ninety-four patients were included in the logistic regression analyses. Patients who had indwelling stents for >90 days were 4.3 times more likely to have resolved strictures [odds ratio, 4.3 (95% confidence interval, 1.24-15.09)] and patients with nonmigrated stents were 5.4 times more likely to have resolved strictures [odds ratio, 5.4 (95% confidence interval, 1.001-29.29)]. CONCLUSIONS: FCSEMS for BBS had an acceptable rate of stricture resolution for postsurgical strictures, gallstone-related strictures, and those due to chronic pancreatitis. Predictors for stricture resolution include longer indwell time and absence of migration. Further study is warranted to assess long-term efficacy in a prospective manner with longer than 3-month time of stent indwelling time.

Evaluation of a fully covered self-expanding metal stent with flared ends in malignant biliary obstruction: a multicenter study.

BACKGROUND AND AIMS: Limited data are available regarding fully covered metal stents in the management of malignant distal biliary strictures. The aim of this study was to evaluate the safety of a fully covered self-expanding metal stent (FCSEMS) with flared ends, in treating malignant biliary strictures. We report our long-term retrospective analysis from 6 centers. METHODS: A total of 260 patients (142 males, median age 68 y) underwent endoscopic retrograde cholangiopancreatography with placement of FCSEMS (WallFlex; Boston Scientific, Natick, MA) for the palliation of obstructive jaundice in the setting of pancreatic adenocarcinoma (169), metastatic disease (36), cholangiocarcinoma (23), ampullary cancer (19), or other (13). Patients were evaluated clinically in follow-up and biochemical tests of liver function were obtained. Data were recorded for the following variables: patient survival, duration of stent patency, the need for subsequent biliary intervention, and complications. RESULTS: A total of 266 FCSEMS were placed in 260 patients. There was a median survival of 100 days (range, 7 to 531 d). There was a mean follow-up of 134±118 days (range, 4 to 519 d). Biliary decompression was successful in 252 patients (97%). At the end of the study period, 121 were alive with a patent stent, 65 patients died with a patent stent, 40 patients were successfully bridged to surgery, 8 patients had their patent stent removed and had no need for further stenting, and 18 patients were lost to follow-up. Five patients who had a successfully placed FCSEMS were considered a failure due to the following reason: migration (2), cholangitis (1), stent occlusion (1), and removal for management of proximal biliary obstruction (1). Two additional patients experienced migration that did not require FCSEMS removal or replacement. Stent replacement was required in 10 patients, of whom 6 had a second FCSEMS placed. The remaining 4 were in the failure group and underwent replacement with either uncovered stents or plastic stents. Other complications, managed conservatively, included pain (2), postendoscopic retrograde cholangiopancreatography pancreatitis (4), fever (1), retroperitoneal perforation (1), and postsphincterotomy bleeding (1). The mean patency duration was 328 days (SE 19.04). The patency percentage was 83% at 3 months, 63% at 6 months, and 48.5% at 12 months. CONCLUSIONS: In the management of malignant distal biliary strictures, the fully covered WallFlex stent has acceptable patency and complication rates. Further long-term prospective data are required to confirm this observation.

Fully covered removable nitinol self-expandable metal stents (SEMS) in malignant strictures of the esophagus: a multicenter analysis.

BACKGROUND: Fully covered esophageal self-expandable metallic stents (SEMS) often are used for palliation of malignant dysphagia. However, experience and data on these stents are still limited. The purpose of this multicenter study was to evaluate the efficacy and safety of fully covered nitinol SEMS in patients with malignant dysphagia. METHODS: 37 patients underwent placement of a SEMS during a 3 year period. Five patients underwent SEMS placement as a bridge to surgery: one for tracheoesophageal fistula in the setting of squamous cell carcinoma of the esophagus, one for perforation in setting of esophageal adenocarcinoma, 27 for unresectable esophageal cancer (16 adenocarcinoma, 11 squamous cell carcinoma), two for lung cancer, and one for breast-cancer-related esophageal strictures. RESULTS: SEMS placement was successful in all 37 patients. Immediate complications after stent deployment included chest pain (n = 6), severe heartburn (n = 1), and upper gastrointestinal bleeding requiring SEMS revision (n = 1). Dysphagia scores improved significantly from 3.2 ± 0.4 before stent placement to 1.4 ± 1.0 at 1 month (P < 0.0001), 1.1 ± 1.2 (P < 0.0001) at 3 months, and 1.3 ± 1.4 (P = 0.0018) at 6 months. The stent was removed in 11 patients (30%) for the following indications: resolution of stricture (n = 3), stent malfunction (n = 5), and stent migration (n = 3). After stent removal, three patients were restented, three underwent dilation, and two underwent PEG placement. Mean survival for the 37 patients after stent placement was 146.3 ± 143.6 (range, 13-680) days. CONCLUSIONS: Our study suggests that fully covered SEMS placement improve dysphagia scores in patients with malignant strictures, particularly in the unresectable population. Further technical improvements in design to minimize long-term malfunction and migration are required.

Interpretation of probe-based confocal laser endomicroscopy of indeterminate biliary strictures: is there any interobserver agreement?

BACKGROUND: Probe-based confocal laser endomicroscopy (pCLE) has enabled in vivo histopathology by obtaining high resolution images of the mucosal layers of the gastrointestinal tract. For indeterminate bile duct strictures, biopsy, cytologic brushing and needle aspiration have low levels of diagnostic accuracy. AIM: The objective of this multi-center pilot study was to assess the interobserver agreement in interpretation of pCLE imaging. METHODS: Twenty-five de-identified pCLE video clips of indeterminate biliary strictures were sent to 6 observers at 5 institutions. Miami Classification was used to standardize image interpretation. Seven variables were assessed for interobserver agreement using the Fleiss kappa statistic which included: presence of thick (>20 µm) or thin (<20 µm) dark or white bands, dark clumps, epithelium including glandular structures, interstitial fluorescein leakage, ease of interpretation, and final diagnosis. Based on operator experience, observers were categorized into 3 categories of experience (Category 1: 0-10; Category 2: 11-20; Category 3: >21 cases). RESULTS: Upon stratification, Category 1 interobserver agreement ranged from "Poor" to "Fair" (κ = 0.277, κ = -0.079, κ = -0.025, κ = -0.066, κ = 0.128, κ = 0.088), and for the final diagnosis variable, the agreement was slight (κ = 0.033). Category 2 and 3 interobserver agreement ranged from "Poor" to "Fair" (κ = 0.211, κ = 0.181, κ = 0.347, κ = 0.238, κ = -0.050, κ = 0.092), and for the final diagnosis variable, the agreement was slight (κ = 0.195). CONCLUSION: The overall interobserver agreement for pCLE image interpretation in indeterminate biliary strictures ranges from poor to fair. Interpretation criteria as well as training require further standardization toward improving inter-rater reliability.

Success and complications associated with placement of fully covered removable self-expandable metal stents for benign esophageal diseases (with videos).

BACKGROUND: Fully covered esophageal self-expandable metal stents (FCSEMSs) are thought to induce less mucosal hyperplasia and are potentially removable. They may constitute an attractive alternative for the treatment of benign esophageal diseases. OBJECTIVE: To evaluate the efficacy and safety of FCSEMSs in the treatment of benign esophageal diseases. DESIGN: Patients referred for management of benign esophageal disease underwent placement of an FCSEMS and were entered into a prospective database and analyzed retrospectively for clinical response, efficacy, and morbidity. SETTING: Two tertiary care centers with long-standing experience in the management of benign esophageal strictures. PATIENTS: Between January 2006 and September 2007, 35 patients (mean age 61 years, range 20-85 years) underwent FCSEMS placement for benign esophageal diseases at 2 tertiary academic medical centers. There were 19 patients with benign esophageal strictures and 16 patients with leaks/perforations. INTERVENTION: Temporary placement of FCSEMS until stricture resolution. MAIN OUTCOME MEASUREMENTS: Clinical response, efficacy, and morbidity. RESULTS: Indications for stent placement were esophageal leak/fistulae (n = 12), refractory benign strictures (n = 10), anastomotic strictures (n = 7), perforations (n = 4), and radiation-induced strictures (n = 2). Immediate complications were chest pain (2 patients), stent migration (2 patients), dysphagia (1 patient), respiratory compromise (1 patient), and arrhythmia (1 patient). Long-term complications included recurrent dysphagia (6 patients), aspiration pneumonia (2 patients), globus sensation (2 patients), abdominal pain (2 patients), and fever (1 patient). Stent migration was observed in 12 patients (34%). After placement, dysphagia scores at 1 month improved significantly from 3.1 ± 1.0 to 1.2 ± 1.3 (P < .0001). A total of 11 of 35 patients (31%) were treated successfully. Specifically, 21% of patients with refractory strictures and 44% of patients with leaks/fistulae had successful long-term outcomes without any need for reinterventions. All stents were retrieved successfully, except for 1 stent, which fractured and was retrieved in 2 pieces without any complications. CONCLUSION: Use of FCSEMSs for benign esophageal conditions was associated with frequent stent migration and long-term improvement in only one third of patients. Further investigation is required before recommending FCSEMS placement to treat benign diseases of the esophagus and to further characterize the subgroup that might benefit from these interventions.

Photodynamic therapy for unresectable cholangiocarcinoma: contribution of single operator cholangioscopy for targeted treatment.

Photodynamic therapy (PDT) for unresectable cholangiocarcinoma is associated with improvement in cholestasis and survival. Single operator cholangioscopy (SOC) has been used for targeted laser illumination. We analyzed our growing experience of SOC with direct PDT. This is a retrospective analysis of a consecutive series of patients prospectively entered into a registry. Forty-five patients (24 male, aged 67.3 ± 10.6 years) were treated with PDT for cholangiocarcinoma during a five-year period. Thirty-two patients were treated with ERCP and PDT alone, and 13 were treated with ERCP and PDT using SOC. The two groups were then compared to observe any statistically significant difference in regards to age, gender, serum bilirubin, MELD score, adverse effects, or survival. An overall median of 1 PDT session per patient (range: 1-9) was performed. Twenty-six total sessions of PDT using SOC were performed in 13 patients with a median of 2.0 sessions per patient (range: 1-6). Median global survival was 168 days (range: 26-1353). Median survival for the PDT-only group was 200 days, and median survival for the PDT-with-SOC group was 386 days (p = 0.45). There was a statistically significant difference (p < 0.0001) between the two groups in regards to fluoroscopy time, with the PDT-only group having a median time of 21.1 min and the PDT-with-SOC group having a median time of 11.1 min. PDT related complications included 7 cases of mild phototoxicity and one case of moderate phototoxicity requiring hospitalization. SOC permits targeted therapy during PDT and can be successfully performed without adverse events while simultaneously reducing exposure to radiation.

Presence of lymph node vasculature: a new EUS criterion for benign nodes?

OBJECTIVES: Lymph nodes normally have prominent centrally located blood vessels, which may become obliterated with tumor infiltration. The presence of intranodal vasculature has been noted to coincide with benign cytology. We sought to determine the test characteristics of the presence of intranodal mediastinal vasculature during endoscopic ultrasound (EUS). METHODS: 67 mediastinal lymph nodes evaluated by EUS in 66 patients over a 1-year period were evaluated for the presence of intranodal vasculature, which was considered benign when it traversed through the node without disruption. RESULTS: Of the 67 lymph nodes evaluated, 29 (43%) were found to be malignant on cytopathologic review. Benign vascular markings were present in 15/67 (22.4%) lymph nodes evaluated. All 15 (100%) of these nodes were found to have benign fine-needle aspiration (FNA) results. The presence of benign vasculature had a negative predictive value of 100%. CONCLUSIONS: The presence of intranodal vasculature was universally associated with a benign diagnosis. The addition of this EUS finding improves the ability to characterize lymph nodes and predict the likelihood of malignant involvement.

Endotherapy for pancreatic necrosis and abscess: endoscopic drainage and necrosectomy.

Pancreatic necrosis and abscess are among the most severe complications of acute pancreatitis. Endoscopic drainage of pancreatic fluid collections has been increasingly performed in many tertiary care centers. The type of fluid collection that is being intervened upon determines the outcome. The development of endoscopic ultrasonography (EUS) has expanded the safety and efficacy of this modality by allowing one to access and drain more challenging fluid collections. The technique and review of current literature regarding endoscopic therapy of pancreatic necrosis and abscess will be discussed.

Temporary placement of a fully covered self-expandable metal stent in the pancreatic duct for management of symptomatic refractory chronic pancreatitis: preliminary data (with videos).

BACKGROUND: Pancreatic duct (PD) stenting is beneficial for the treatment of pain in patients with PD strictures associated with chronic pancreatitis. Placement of metal stents has been reported but failed secondary to hyperplasia or migration. OBJECTIVE: To investigate the outcome of patients with symptomatic and refractory PD strictures who had temporary placement of a covered self-expandable metal stent (CSEMS). DESIGN: Patients with refractory PD strictures were offered temporary CSEMS placement. Pain scores were evaluated before and after CSEMS placement. SETTING: A tertiary-care center. PATIENTS: Six patients (4 men, mean age +/- SD 55 +/- 8 years) received a CSEMS, and 5 patients had removal of a CSEMS after a mean time of 92 days. INTERVENTION: Placement of CSEMS (8-mm or 10-mm diameter VIABIL) in the PD, with removal after 3 months. MAIN OUTCOME MEASUREMENTS: The pain score before and after stent placement and the sustained response after removal. Morbidity associated with stent placement and removal was also noted. RESULTS: Pain scores after CSEMS placement significantly improved (P = .024), from 6.4 to 1.6. Of the 5 patients who underwent CSEMS removal, 3 developed recurrent symptomatic pancreatic stricture, of whom 2 required repeat stenting with a larger-diameter CSEMS (10 mm) and 2 remained pain free. The CSEMS was not removed in 1 patient because pancreatic malignancy was diagnosed. There were no complications during placement or removal of CSEMSs. LIMITATION: This was a pilot study. CONCLUSION: Temporary placement of CSEMSs in patients with symptomatic refractory PD stricture offers transient relief of pain. Further investigation is needed to determine the optimal diameter and duration of placement.

Transenteric drainage of pancreatic-fluid collections with fully covered self-expanding metallic stents (with video).

BACKGROUND: Drainage of pancreatic-fluid collections (PFCs) by using fully covered self-expanding metallic stents (CSEMSs) offers the option of providing a larger-diameter access fistula for drainage when compared with plastic stents. OBJECTIVE: To evaluate the efficacy and safety of transenteric drainage of PFCs by using CSEMSs. DESIGN: A prospective case series. SETTING: A tertiary-referral center. PATIENTS: Between January 2007 and September 2007, 18 patients underwent drainage of PFCs by using CSEMSs. Follow-up and final results were prospectively recorded until May 2008. INTERVENTIONS: Placement of CSEMSs with a double-pigtail stent placed alongside (4 cases) or into the CSEMS (14 cases) to prevent migration. MAIN OUTCOME MEASUREMENTS: The number of sessions and time to resolution of the PFCs. RESULTS: A median of 1 session was required to achieve drainage (range 1-4) when using CSEMSs. Complications included superinfection (5), bleeding (2), and inner migration (1). A total of 17 of 18 patients (95%) responded successfully, with 14 patients (78%) achieving complete resolution of their PFC. The mean (+/- SD) time of follow-up until final resolution was 77 +/- 80 days (range 15-310 days). CONCLUSIONS: Placement of CSEMSs seems to offer an effective and safe alternative for the drainage of PFCs. A randomized controlled trial should be performed to compare this technique with plastic-stent drainage.

Endoscopic drainage of pancreatic fluid collections using a fully covered expandable metal stent with antimigratory fins.

BACKGROUND AND OBJECTIVES: Endoscopic drainage is the first consideration in treating pancreatic fluid collections (PFCs). Recent data suggests it may be useful in complicated PFCs as well. Most of the available data assess the use of plastic stents, but scarce data exists on metal stent management of PFCs. The aim of our study to evaluate the efficacy and safety of a metal stent in the management of PFCs. PATIENTS AND METHODS: Data were collected prospectively on 47 patients diagnosed with PFCs from March 2007 to August 2011 at 3 tertiary care centers. These patients underwent endoscopic transmural placement of a fully covered self-expanding metal stent (FCSEMS) with antimigratory fins of 10 mm diameter. RESULTS: The stent was successfully placed in all patients, and left in place an average of 13 weeks (range 0.4-36 weeks). Etiology of the PFC was biliary pancreatitis (23), pancreas divisum (2), trauma (4), hyperlipidemia (3), alcoholic (8), smoking (2), idiopathic (4), and medication-induced (1). PFCs resolved in 36 patients, for an overall success rate of 77%. Complications included fever (3), stent migration (2) and abdominal pain (1). CONCLUSIONS: The use of FCSEMS is successful in the majority of patients with low complication rates. A large sample-sized RCT is needed to confirm if the resolution of PFCs is long-standing.

Photodynamic therapy in unresectable cholangiocarcinoma: not for the uncommitted.

BACKGROUND/AIMS: Photodynamic therapy (PDT) in unresectable cholangiocarcinoma has been associated with improved survival. We report a single tertiary care center experience over the past 6 years. METHODS: Fifty-five patients with unresectable cholangiocarcinoma received PDT between 2004 and 2010. Plastic stents were placed after PDT to prevent cholangitis. RESULTS: Twenty-seven patients (49%) showed Bismuth type IV, 22 (41%) showed Bismuth type III, and six (10%) showed Bismuth type I and II. Twenty patients (37%) received chemotherapy and radiation therapy, five (9%) received chemotherapy only; and one (2%) received radiation therapy only. Mean number of PDT sessions was 1.9±1.5 sessions (range, 1 to 9). Mean survival duration was 293±266 days (median, 190; range, 25 to 1,332). PDT related complications included three (5%) facial burn, three (5%) photosensitivity, and two (3%) rash. Kaplan-Meier analysis comparing the survival means of patients who received PDT and chemotherapy/radiation therapy (median survival 257 days; 95% confidence interval [CI], 166 to 528) versus who received PDT only (median survival 183 days; 95% CI, 129 to 224) showed no significant difference (log-rank p=0.20). CONCLUSIONS: PDT has a measurable impact on survival in unresectable cholangiocarcinoma but requires aggressive stenting posttherapy.

Photodynamic therapy for cholangiocarcinoma.

Cholangiocarcinoma is the primary malignancy arising from the biliary epithelium, and it presents as jaundice, cholestasis, and cholangitis. Over 50 percent of patients present with advanced-stage disease, and the prognosis is poor with the survival measured in months even after biliary decompression. Palliative management has become the standard of care for unresectable disease, and this involves an endoscopic approach. Photodynamic therapy (PDT) involves the administration of a photosensitizer followed by local irradiation with laser therapy. The use of PDT for palliation of bile-duct tumors has produced promising results. Several studies conducted in Europe and the United States have shown that PDT produces a marked improvement in the symptoms of cholestasis, survival, and quality of life. This chapter summarizes the principle of PDT, the technique employed, and the published experience regarding PDT for cholangiocarcinoma.

EUS-guided drainage of bilomas: a new alternative?

BACKGROUND: Bilomas have traditionally been treated by either percutaneous drainage or surgery. However, percutaneous drainage is associated with discomfort and infection, whereas surgery, which is usually reserved for refractory cases, has high morbidity and mortality rates. Recently, endoscopic drainage of bilomas adjacent to the GI lumen has been reported in isolated reports. OBJECTIVE: We analyzed our 4 years' experience with this innovative technique. DESIGN: Patients with symptomatic bilomas were offered EUS-guided drainage and were followed up prospectively for clinical and radiologic responses. SETTING: Tertiary care center with long-standing experience in EUS-guided drainage. PATIENTS: A total of 5 patients underwent EUS-guided transenteric drainage of symptomatic bilomas. INTERVENTION: The technique included transenteric EUS-guided puncture, placement of a guidewire into the biloma, and creation of an enteral-biloma fistula with placement of a plastic endoprosthesis after balloon dilation. In 4 cases, the stents were removed at a mean of 6.8 +/- 4.3 weeks. In one patient with malignancy, the stent was left in place for palliation. MAIN OUTCOME MEASUREMENTS: Efficacy and safety of EUS-guided drainage of bilomas. RESULTS: EUS-guided transenteric biloma drainage was successfully performed in 5 patients without any significant morbidity. Biloma resolution was confirmed in all 5 patients, and none of the 4 patients relapsed after stent removal (mean follow-up of 12.8 +/- 6.1 months). CONCLUSIONS: EUS-guided drainage of bilomas is technically feasible, appears safe, and provides an attractive alternative to percutaneous or surgical drainage.