Shunsuke Omoto

Contrast-enhanced harmonic endoscopic ultrasonography for differential diagnosis of pancreatic cysts

BACKGROUND AND STUDY AIM Comparison of fundamental B-mode endoscopic ultrasonography (FB-EUS) and contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) in the differential diagnosis of pancreatic cysts according to presence of mural nodules. PATIENTS AND METHODS Between April 2007 and April 2012, FB-EUS and CH-EUS data were prospectively collected from 581 consecutive patients with pancreatic cysts, and were retrospectively analyzed from 70 with subsequent cyst resection. Presence and height of mural nodules as detected on FB-EUS and CH-EUS were evaluated, and thence accuracies of both methods for diagnosing mucinous versus nonmucinous and malignant versus benign cysts. RESULTS On pathological examination 48 cysts were mucinous and 22 were nonmucinous; 30 cysts were malignant (high grade dysplasia or invasive carcinoma) and 40 were benign. If presence of a mural nodule was considered to indicate a mucinous cyst, FB-EUS and CH-EUS accuracies did not differ significantly (respectively: sensitivity 85 % vs. 79 %; specificity 46 % vs. 96 %; accuracy 73 % vs. 84 %, P = 0.057). If presence of mural nodule was considered to indicate malignancy, CH-EUS was significantly more accurate than FB-EUS (respectively: sensitivity 97 % vs. 97 %; specificity 75 % vs. 40 %; accuracy 84 % vs. 64 %, P = 0.0001). For diagnosing malignancy by evaluating mural nodule height, the area under the receiver operating characteristic (AUROC) was 0.84 and 0.93 for FB-EUS and CH-EUS, respectively (P = 0.028). Presence of a mural nodule of height ≥ 4 mm on CH-EUS was a sign of malignancy (false-positive fraction 0.2; true-positive fraction 0.93; odds ratio 56.0). CONCLUSIONS CH-EUS is more accurate than FB-EUS for diagnosing malignant pancreatic cysts.

Contrast-enhanced harmonic endoscopic ultrasonography for assessment of lymph node metastases in pancreatobiliary carcinoma.

AIM To assess the usefulness of contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) for lymph node metastasis in pancreatobiliary carcinoma. METHODS All patients suspected of pancreatobiliary carcinoma with visible lymph nodes after standard EUS between June, 2009 and January, 2012 were enrolled. In the primary analysis, patients with successful EUS-fine needle aspiration (FNA) were included. The lymph nodes were assessed by several standard EUS variables (short and long axis lengths, shape, edge characteristic and echogenicity), color Doppler EUS variable [central intranodal blood vessel (CIV) presence] and CH-EUS variable (heterogeneous/homogeneous enhancement patterns). The diagnostic accuracy relative to EUS-FNA was calculated. In the second analysis, N-stage diagnostic accuracy of CH-EUS was compared with EUS-FNA in patients who underwent surgical resection. RESULTS One hundred and nine patients (143 lymph nodes) fulfilled the criteria. The short axis cut-off ≥ 13 mm predicted malignancy with a sensitivity and specificity of 72% and 85%, respectively. These values were 72% and 63% for the long axis cut-off ≥ 20 mm, 62% and 75% for the round shape variable, 81% and 30% for the sharp edge variable, 66% and 61% for the hypoechogenicity variable, 70% and 72% for the CIV-absent variable, and 83% and 91% for the heterogeneous CH-EUS-enhancement variable, respectively. CH-EUS was more accurate than standard and color Doppler EUS, except the short axis cut-off. Notably, three patients excluded because of EUS-FNA failure were correctly N-staged by CH-EUS. CONCLUSION CH-EUS complements standard and color Doppler EUS and EUS-FNA for assessment of lymph node metastases.

Urgent endoscopic ultrasound-guided choledochoduodenostomy for acute obstructive suppurative cholangitis-induced sepsis

Acute obstructive suppurative cholangitis (AOSC) due to biliary lithiasis is a life-threatening condition that requires urgent biliary decompression. Although endoscopic retrograde cholangiopancreatography (ERCP) with stent placement is the current gold standard for biliary decompression, it can sometimes be difficult because of failed biliary cannulation. In this retrospective case series, we describe three cases of successful biliary drainage with recovery from septic shock after urgent endoscopic ultrasound-guided choledochoduodenostomy (EUS-CDS) was performed for AOSC due to biliary lithiasis. In all three cases, technical success in inserting the stents was achieved and the patients completely recovered from AOSC with sepsis in a few days after EUS-CDS. There were no procedure-related complications. When initial ERCP fails, EUS-CDS can be an effective life-saving endoscopic biliary decompression procedure that shortens the procedure time and prevents post-ERCP pancreatitis, particularly in patients with AOSC-induced sepsis.

New endoscopic ultrasonography techniques for pancreaticobiliary diseases

Endoscopic ultrasonography (EUS) is widely used to evaluate pancreaticobiliary diseases, especially pancreatic masses. EUS has a good ability to detect pancreatic masses, but it is not sufficient for the differential diagnosis of various types of lesions. In order to address the limitations of EUS, new techniques have been developed to improve the characterization of the lesions detected by EUS. EUS-guided fine needle aspiration (EUS-FNA) has been used for diagnosing pancreatic tumors. In order to improve the histological diagnostic yield, a EUS-FNA needle with a core trap has recently been developed. Contrast-enhanced harmonic EUS is a new imaging modality that uses an ultrasonographic contrast agent to visualize blood flow in fine vessels. This technique is useful in the diagnosis of pancreatic solid lesions and in confirming the presence of vascularity in mural nodules for cystic lesions. EUS elastography analyzes several different variables to measure tissue elasticity, color patterns, and strain ratio, using analytical techniques such as hue-histogram analysis, and artificial neural networks, which are useful for the diagnosis of chronic pancreatitis and pancreatic cancer.

Predictors of pain response in patients undergoing endoscopic ultrasound-guided neurolysis for abdominal pain caused by pancreatic cancer

Background: Interventional endoscopic ultrasound (EUS)-guided procedures such as EUS-guided celiac ganglia neurolysis (EUS-CGN) and EUS-guided broad plexus neurolysis (EUS-BPN) were developed to treat abdominal cancer-associated pain; however, these procedures are not always effective. The aim of this study was to explore predictors of pain response in EUS-guided neurolysis for pancreatic cancer-associated pain. Methods: This was a retrospective analysis of prospectively collected data of 112 consecutive patients who underwent EUS-BPN in our institution. EUS-CGN was added in cases of visible celiac ganglia. The neurolytic-spread area was divided into six sections and evaluated by post-procedural computed tomography scanning. Pain intensity was assessed using a visual analog scale (VAS), and a decrease in VAS scores by ⩾3 points after neurolysis was considered a good pain response. Univariable and multivariable logistic regression analyses were performed to explore predictors of pain response at 1 and 4 weeks, and complications. Results: A good pain response was obtained in 77.7% and 67.9% of patients at 1 and 4 weeks, respectively. In the multivariable analysis of these patients, the combination method (EUS-BPN plus CGN) was a significant positive predictive factor at 1 week (odds ratio = 3.69, p = 0.017) and 4 weeks (odds ratio = 6.37, p = 0.043). The numbers of neurolytic/contrast spread areas (mean ± SD) were 4.98 ± 1.08 and 4.15 ± 1.12 in patients treated with the combination method and single method, respectively (p < 0.001). There was no significant predictor of complications. Conclusions: EUS-BPN in combination with EUS-CGN was a predictor of a good pain response in EUS-guided neurolysis for pancreatic cancer-related pain. The larger number of neurolytic/contrast spread areas may lead to better outcomes in patients receiving combination treatment.

Endoscopic ultrasonography‐guided choledochoduodenostomy using a newly designed laser‐cut metal stent: Feasibility study in a porcine model

Endoscopic ultrasonography (EUS)‐guided choledochoduodenostomy (EUS‐CDS) is increasingly used in the treatment of malignant distal biliary obstruction. Standardized use of this technique requires improvements in instruments, including more convenient and safer devices. The present study was designed to evaluate the resistance force to migration (RFM) of a newly designed laser‐cut metal stent and the feasibility of EUS‐CDS using this stent.

Evaluation of anti-migration properties of biliary covered self-expandable metal stents.

AIM To assess anti-migration potential of six biliary covered self-expandable metal stents (C-SEMSs) by using a newly designed phantom model. METHODS In the phantom model, the stent was placed in differently sized holes in a silicone wall and retracted with a retraction robot. Resistance force to migration (RFM) was measured by a force gauge on the stent end. Radial force (RF) was measured with a RF measurement machine. Measured flare structure variables were the outer diameter, height, and taper angle of the flare (ODF, HF, and TAF, respectively). Correlations between RFM and RF or flare variables were analyzed using a linear correlated model. RESULTS Out of the six stents, five stents were braided, the other was laser-cut. The RF and RFM of each stent were expressed as the average of five replicate measurements. For all six stents, RFM and RF decreased as the hole diameter increased. For all six stents, RFM and RF correlated strongly when the stent had not fully expanded. This correlation was not observed in the five braided stents excluding the laser cut stent. For all six stents, there was a strong correlation between RFM and TAF when the stent fully expanded. For the five braided stents, RFM after full stent expansion correlated strongly with all three stent flare structure variables (ODF, HF, and TAF). The laser-cut C-SEMS had higher RFMs than the braided C-SEMSs regardless of expansion state. CONCLUSION RF was an important anti-migration property when the C-SEMS did not fully expand. Once fully expanded, stent flare structure variables plays an important role in anti-migration.

Utility of Endoscopic Ultrasound-Guided Hepaticogastrostomy with Antegrade Stenting for Malignant Biliary Obstruction after Failed Endoscopic Retrograde Cholangiopancreatography

Background: Endoscopic ultrasound (EUS)-guided biliary drainage (BD) is a well-recognized alternative BD method after unsuccessful endoscopic transpapillary drainage. EUS-guided hepaticogastrostomy (HGS) with antegrade stenting (AGS) was recently applied to the treatment of malignant obstructive jaundice. Objective: To assess the efficacy and safety of HGS combined with AGS for treatment of malignant biliary stricture-induced obstructive jaundice. Design: Retrospective cohort study. Setting: Single academic tertiary care center. Patients: From January 2006 to December 2014, endoscopic retrograde cholangiopancreatography was attempted in patients with obstructive jaundice; it was successful in 641 patients and impossible in 154 patients (postsurgically altered anatomy or duodenal stenosis, n = 101; difficult cannulation, n = 53). In total, 145 patients underwent EUS-guided BD; HGS and HGS with AGS were attempted in 42 patients (Group A, January 2006-August 2011) and 37 patients (Group B, September 2011-December 2014), respectively. Interventions: Under EUS and fluoroscopy guidance, HGS and HGS with AGS were performed via needle puncture, guidewire insertion, puncture-hole dilation, and stent placement. Main Outcome Measurements: Groups A and B were compared in terms of technical success, functional success, adverse event rates, re-intervention rates, patient survival time, and time to stent dysfunction or patient death. The two groups were also compared in a subgroup analysis of only 28 patients who underwent chemotherapy. Results: The technical success rate was significantly higher in Group A than B (97.6 vs. 83.8%, p = 0.03). The functional success rate was comparable between the two groups (90.2 vs. 90.3%), although the rate of adverse events was significantly higher in Group A than B (26.1 vs. 10.8%, p = 0.03). The re-intervention rate tended to be higher in Group A than B (16.7 vs. 8.1%, p = 0.25). Groups A and B did not differ significantly in terms of median overall patient survival (75 vs. 61 days, p = 0.70) or median time to stent dysfunction or patient death (68 vs. 63 days, p = 0.08). Among patients who underwent chemotherapy, there was no difference in overall patient survival time between the two groups (121 vs. 157 days, p = 0.08), although time to stent dysfunction or patient death was significantly shorter in Group A than B (71 vs. 95 days, p = 0.02). Conclusion: Although the technical success rate of HGS with AGS was lower than that of HGS, HGS with AGS was superior to HGS in terms of adverse event rate and stent patency in patients receiving chemotherapy.

Characterization of Pancreatic Tumors with Quantitative Perfusion Analysis in Contrast-Enhanced Harmonic Endoscopic Ultrasonography

Objectives: This study evaluated whether quantitative perfusion analysis with contrast-enhanced harmonic (CH) endoscopic ultrasonography (EUS) characterizes pancreatic tumors, and compared the hemodynamic parameters used to diagnose pancreatic carcinoma. Methods: CH-EUS data from pancreatic tumors of 76 patients were retrospectively analyzed. Time-intensity curves (TIC) were generated to depict changes in signal intensity over time, and 6 parameters were assessed: baseline intensity, peak intensity, time to peak, intensity gain, intensity at 60 s (I60), and reduction rate. These parameters were compared between pancreatic carcinomas (n = 41), inflammatory pseudotumors (n = 14), pancreatic neuroendocrine tumors (n = 14), and other tumors (n = 7). All 6 TIC parameters and subjective analysis for diagnosing pancreatic carcinoma were compared. Results: Values of peak intensity and I60 were significantly lower and time to peak was significantly longer in the groups with pancreatic carcinomas than in the other 3 tumor groups (p < 0.05). Reduction rate was significantly higher in pancreatic carcinomas than in pancreatic neuroendocrine tumors (p < 0.05). Areas under the receiver-operating characteristic curves for the diagnosis of pancreatic carcinoma using subjective analysis, baseline intensity, peak intensity, intensity gain, I60, time to peak, and reduction rate, were 0.817, 0.664, 0.810, 0.751, 0.845, 0.777, and 0.725, respectively. I60 was the most accurate parameter for differentiating pancreatic carcinomas from the other groups, giving values of sensitivity/specificity of 92.7/68.6% when optimal cutoffs were chosen. Conclusions: In pancreatic carcinomas, TIC patterns were markedly different from the other tumor types, with I60 being the most accurate diagnostic parameter. Quantitative perfusion analysis is useful for differentiating pancreatic carcinomas from other pancreatic tumors.

Association between the Risk Factors for Pancreatic Ductal Adenocarcinoma and Those for Malignant Intraductal Papillary Mucinous Neoplasm

Background and Aims: Risk factors for pancreatic ductal adenocarcinoma (PDAC) include diabetes mellitus, chronic pancreatitis, obesity, a family history of pancreatic cancer, and a history of smoking or alcohol consumption. The aim of this study was to evaluate the association between risk factors for PDAC and malignant intraductal papillary mucinous neoplasm (IPMN). Methods: The study included 134 consecutive patients with IPMN who underwent surgical resection at Kindai University Hospital between April 2009 and March 2015. Data on the presence or absence of mural nodules (MNs) and risk factors for PDAC were evaluated. Multivariable logistic regression analysis was performed with malignant IPMN as the outcome variable and MNs and risk factors for PDAC as explanatory variables. Results: The odds ratio of malignant IPMN to MNs was 3.88 (95% confidence interval [CI] 1.53-9.84; p = 0.004), whereas that of malignant IPMN to smoking history was 1.66 (95% CI 0.74-3.71; p = 0.22). When the presence of MNs was considered as a predictive factor for malignancy, the sensitivity and specificity were 88.5 and 32.1%, respectively, whereas when the presence of both smoking history and MNs was considered, the specificity improved to 73.2%, with a decrease in sensitivity to 42.3%. Conclusions: The presence of both a smoking history and MNs was a valuable predictive factor for malignant IPMN with high specificity. A smoking history should be considered before surgical resection in addition to the presence of MNs.