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OBJECTIVES This prospective multicenter study aimed to assess and compare the accuracy of tissue harmonic endoscopic ultrasonography (TH-EUS) and contrast-enhanced harmonic endoscopic ultrasonography (CH-EUS) for differentiating pancreatic carcinoma from other pancreatic tumors. METHODS Consecutive patients with solid pancreatic tumors were prospectively enrolled between August 2013 and December 2014. To assess the accuracy of TH-EUS and CH-EUS, we compared four parameters of TH-EUS (fuzzy edge, irregular periphery, hypoechogenicity, and heterogeneous internal echogenicity) and four parameters of CH-EUS (hypoenhancement and heterogeneous enhancement in the early and late phases, respectively) to investigate which parameter of each method was most suitable to diagnose pancreatic carcinomas. Interobserver agreement and the diagnostic ability of pancreatic carcinoma using TH-EUS and CH-EUS were assessed and compared. RESULTS A total of 204 patients were enrolled. For the diagnosis of pancreatic carcinoma, interobserver agreement by experts and nonexperts was 0.33-0.50 and 0.35-0.50 for TH-EUS, respectively, and 0.72-0.74 and 0.20-0.54 for CH-EUS, respectively. Irregular periphery was the most accurate diagnostic parameter among TH-EUS findings for differentiating pancreatic carcinomas, with sensitivity, specificity, and accuracy of 95.0%, 42.9%, and 78.9%, respectively. Late phase hypoenhancement was the most accurate diagnostic parameter among CH-EUS findings for differentiating pancreatic carcinomas, with sensitivity, specificity, and accuracy of 90.8%, 74.6%, and 85.8%, respectively. The accuracy of CH-EUS (late phase hypoenhancement) for diagnosis of pancreatic carcinoma was significantly higher than that of TH-EUS (irregular periphery) (p

A free-space optical (FSO) receiver with high optical alignment robustness configured by a single optical lens is presented, in addition to a newly developed 2-D photodetector array (2D-PDA). A 6 × 6 square-shaped aligned arrangement matrix structure in the 2D-PDA provides a large active area for photodetection. In a 1.5-m FSO demonstration, the optical alignment tolerance on the receiver's lens is evaluated to be as large as 12 mm. The multiple-output signals from the 2D-PDA are used for the maximum ratio combining method in space diversity. The system design and alignment tolerance without a mechanical beam-tracking system are presented and the bit error rate contributed by space diversity is discussed.

Background and aims Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) is used for the histopathological diagnosis of any type of gastrointestinal disease. Few adverse events are experienced with this procedure; however, the actual rate of adverse events remains unclear. This study aimed to clarify the current status of cases that experienced adverse events related to the EUS-FNA procedure used for histopathologic diagnoses. Methods A retrospective analysis of cases with EUS-FNA-related adverse events in Japanese tertiary centers was conducted by assessing the following clinical data: basic case information, FNA technique, type of procedural adverse events, and prognosis. Results Of the 13,566 EUS-FNA cases overall, the total number of cases in which adverse events related to EUS-FNA occurred was 234. The incidence of EUS-FNA-related adverse events was ~1.7%. Bleeding and pancreatitis cases accounted for ~49.1% and 26.5% of all adverse events, respectively. Bleeding was the most common adverse event with only seven cases requiring blood transfusion. In cases with neuroendocrine tumors, pancreatitis was the most frequent adverse event. Needle tract seeding because of EUS-FNA was observed during the follow-up period in only ~0.1% of cases with pancreatic cancer. There was no mortality because of adverse events caused by EUS-FNA. Conclusions This study revealed that the adverse events-related EUS-FNA for histopathologic diagnoses were not severe conditions, and had low incidence.

An 83-year-old man without specific symptoms was referred to our hospital for further evaluation and treatment of apparent double primary tumors of the cystic duct and common bile duct. Computed tomography showed contrast-enhanced solid tumors in the cystic duct and common bile duct. Magnetic resonance imaging showed that the bile duct tumor was isointense on T1-weighted images and had low intensity on T2-weighted images. In addition, the bile duct tumor showed high intensity on diffusion-weighted images. Endoscopic ultrasonography revealed the tumor of the common bile duct and endoscopic retrograde cholangiopancreatography demonstrated a filling defect in the bile duct. The cystic duct was not identified on endoscopic ultrasonography or endoscopic retrograde cholangiopancreatography. Transpapillary biopsy of the bile duct tumor showed adenocarcinoma. The patient was diagnosed with double primary tumors of the cystic duct and the common bile duct and underwent subtotal stomach-preserving pancreaticoduodenectomy. Microscopic examination with molecular profiling of the tumors revealed a high-grade noninvasive intracholecystic papillary neoplasm of the cystic duct extending into the common bile duct and forming a tubulopapillary neoplasm with invasion of the common bile duct.

Background/objectives Pancreatic neuroendocrine carcinoma (PanNEC)-G3 often presents along with genetic abnormalities such as KRAS, RB1, and TP53 mutations. However, the association between these genetic findings and response to chemotherapy and prognosis has not been clarified. This study aimed to clarify the clinicopathological features of PanNEC-G3. Methods We performed a subgroup analysis of the Japanese PanNEN-G3 study (multicenter, retrospective study), which revealed that Rb loss and KRAS mutation were predictors of the response to platinum-based regimen in PanNEN-G3. We re-classified WHO grades of PanNENs using the 2017 WHO classification and then analyzed the clinicopathological features and prognostic factors in 49 patients with PanNEC-G3. Results The rates of Rb loss and KRAS mutation in PanNEC-G3 were 54.5% and 48.7%, respectively. Patients with Rb loss and/or KRAS mutation showed a higher response rate to first-line platinum-based regimen than those without Rb loss or KRAS mutation (object response rate 70.0% vs 33.3%, odds ratio 9.22; 95% CI 1.26–67.3, P = 0.029), but tended to have shorter overall survival rates than those without Rb loss or KRAS mutation (median 239 vs 473 days, hazard ratio 2.11; 95% CI 0.92–4.86, P = 0.077). Conclusions Patients with PanNEC-G3 have varied clinical outcomes for platinum-based regimen. When grouped based on Rb loss and KRAS mutation, there seemed to be two groups with distinct prognoses and responses to the platinum-based regimen. PanNEC-G3 could, therefore, be classified into two distinct groups based on immunohistochemical and genetic findings.

The biopsy-based diagnosis of autoimmune pancreatitis (AIP) is difficult but is becoming imperative for pathologists due to the increased amount of endoscopic ultrasound-guided biopsy tissue. To cope with this challenge, we propose guidance for the biopsy diagnosis of type 1 AIP. This guidance is for pathologists and comprises three main parts. The first part includes basic issues on tissue acquisition, staining, and final diagnosis, and is intended for gastroenterologists as well. The second part is a practical guide for diagnosing type 1 AIP based on the AIP clinical diagnostic criteria 2018. Inconsistent histological findings, tips for evaluating IgG4 immunostaining and key histological features including the ductal lesion and others are explained. Storiform fibrosis and obliterative phlebitis are diagnostic hallmarks but are sometimes equivocal. Storiform fibrosis is defined as spindle-shaped cells, inflammatory cells and fine collagen fibers forming a flowing arrangement. Obliterative phlebitis is defined as fibrous venous obliteration with inflammatory cells. Examples of each are provided. The third part describes the differentiation of AIP from pancreatic ductal adenocarcinoma (PDAC), focusing on histological features of acinar-ductal metaplasia in AIP, which is an important mimicker of PDAC. This guidance will help standardize pathology reports of pancreatic biopsies for diagnosing type 1 AIP.

We demonstrate the first W-band optoelectronic oscillator (OEO), that oscillates at 94.5 GHz with a measured single side band (SSB) phase noise of −101 dBc/Hz at an offset frequency of 10 kHz from the carrier. Side mode suppression of more than 65 dB has been achieved by using injection locking. This OEO has potential application as a signal source in emerging W-band applications (e.g. fiber-wireless links) and opens a path to low phase noise sources beyond 100 GHz.

Some situations may require endoscopy during the COVID-19 (Coronavirus Disease 2019) pandemic. Here, we describe the necessary precautions in the form of clinical questions and answers (Q&A) regarding the safe deployment of gastrointestinal endoscopy in such situations while protecting endoscopy staff and patients from infection. Non-urgent endoscopy should be postponed. The risk of infection in patients should be evaluated in advance by questionnaire and body temperature. The health of staff must be checked every day. Decisions to employ endoscopy should be based on the institutional conditions and aims of endoscopy. All endoscopic staff need to wear appropriate personal protective equipment (PPE). The endoscope and other devices should be cleaned and disinfected after procedures in accordance with the relevant guidelines. Optimal management of the endoscopy unit is required. Endoscopy for infected patients or those with suspected infection demands exceptional caution. When a patient who undergoes endoscopy is later found to have COVID-19, the members of staff involved are considered exposed to the virus and must not work for at least 14 days if their PPE is considered insufficient. When PPE resources are limited, some equipment may be used continuously throughout a shift as long as it is not contaminated. Details of the aforementioned protective measures are described.

A 58-year-old man was referred for obstructive jaundice. Imaging modalities revealed the presence of multiple pancreatic tumors and the stenosis of the middle common bile duct due to a hypoenhanced localized tumor. The multiple pancreatic tumors were histopathologically diagnosed as autoimmune pancreatitis by endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA). To differentiate between IgG4-related sclerosing cholangitis (IgG4-SC) and cholangiocarcinoma, we diagnosed the biliary tumor as IgG4-SC by EUS-FNA because of insufficient pathological materials obtained in a transpapillary manner. We herein report a case of IgG4-SC diagnosed by EUS-FNA.

Background/Aims: The aim of this study was to evaluate the safety and efficacy of partially covered self-expandable metallic stents (PCSEMS) in patients undergoing neoadjuvant chemo (radio) therapy (NAC) for pancreatic cancer (PC). Methods: This was a prospective multicenter study to evaluate the safety and efficacy of PC-SEMS in patients receiving NAC for resectable and borderline resectable PC. The primary endpoint was the rate of recurrent biliary obstruction (RBO). Results: Twenty-six patients with PC (three with resectable PC and 23 with borderline resectable PC) who underwent NAC at seven Japanese centers were included in the analysis. Both the technical and functional success rates of PCSEMS placement were 100%. Early stent-related complications were observed in three patients (11.5%): mild pancreatitis (n=2) and mild liver abscess (n=1). The median time to surgery or palliation was 4.0 months. Surgical resection was eventually performed in 73.1% of patients, and stent removal during surgery was successful in all patients. RBO was observed in nine patients (34.6%): seven with stent occlusion, one with kinking and one with migration. The RBO rates in resected cases and nonresected cases were 36.8% and 28.6%, respectively. Conclusions: Biliary drainage by PCSEMS was safe and feasible in patients undergoing NAC for resectable and borderline resectable PC. (Gut Liver 2021;15:135-141)

To achieve an ultra-compact and flexible coherent transceiver solution, a carrier-less coherent detection technique using a two-dimensional (2-D) photodetector array (PDA) is proposed based on the idea of phase retrieval (PR). In the proposed PR-based coherent receiver, the optical phase information is digitally reconstructed from multiple intensity-only measurements acquired by arrayed photodetectors; neither local light sources, optical hybrids, nor spatial demultiplexers are needed. We develop a robust and low-complexity PR algorithm, which exploits prior knowledge on the optical modulation format, for the proposed PR receiver. As a proof-of-concept, the coherent detection of 10-Gbaud optical phase-modulated signals, including QPSK, 16-QAM, coherent optical OFDM, and polarization-multiplexed QPSK signals, using only a 2-D PDA is demonstrated experimentally.

A linear-cell-based radio-over-fiber (LC-RoF) system is proposed and demonstrated for efficient mobile communication in high-speed trains without hard handover processes. The configuration of the LC-RoF network and possible router architectures are discussed for the field trial test of the proposed system and for advanced systems in the future. Via the LC-RoF network, 90-GHz, millimeter-wave radio access between the ground and a train car is operated in a centralized manner. The resulting throughput of 1.5 Gbit/s is achieved in the field trial test, which is comprised of 250-Mbaud four-subcarrier differential quadrature phase-shift keying with a forward-error correction code implemented in field-programmable gate arrays to the Shinkansen train traveling at 240 km/h without any interruptions in the connections at the change of radio access units.

Yuki and colleagues report a case of successful endoscopic hemostasis of post-papillectomy bleeding with the gel immersion method and an endoscope with an attached balloon and a cylindrical hood. The visual field was improved with gel and maneuverability was improved using the cylindrical hood and the semi-inflating balloon.

We present a compact hybrid photoreceiver module integrated with a high-bandwidth photodetector and a temperature-stable 1.5-μm quantum dot high-gain semiconductor optical amplifier instead of a transimpedance amplifier at 80 Gbaud.

We propose and demonstrate a 3×3 full multiple-input multiple-output (MIMO) fiber-wireless system in the W-band with wavelength-division multiplexing (WDM) and polarization-division multiplexing (PDM) radio-over-fiber (RoF) transmission capability. The system is realized using two highly stable RoF links based on the optical self-heterodyne method and PDM transmission in one of the RoF links. We experimentally demonstrate and confirm satisfactory performances for a 3×3 MIMO offset quadrature amplitude modulation-based filter-bank multicarrier signal. Total capacities of approximately 110 and 132 Gb/s, corresponding to spectral efficiencies of approximately 8.5 and 10.2 bits/s/Hz, respectively, are achieved for the system using antennas placed in the same and alternately different polarizations, respectively. The system is applicable to WDM and combined WDM/PDM RoF transmissions. It provides a scalable solution for facilitating large-scale MIMO signal transportation and can be a promising solution for future mobile transport and radio access networks in high-frequency bands. ispartof: Journal Of Lightwave Technology vol:39 issue:24 pages:7794-7803 status: published

In-service monitoring and adaptive digital compensation of analog imperfections in optical transponders are vital in the next-generation optical coherent transmission systems employing extremely high-order, high-speed modulation formats. A notable example of such analog impairments is the imbalance of amplitude, phase, and/or timing between the in-phase (I) and quadrature (Q) tributaries in an optical IQ modulator, namely the IQ imbalance. Recently, an IQ-imbalance estimation technique based on phase retrieval without using a coherent receiver, the so-called single-pixel optical modulation analyzer (SP-OMA), has been proposed as an affordable in-service monitoring solution for the frequency-dependent IQ imbalance in a (single-polarization) IQ modulator. In this work, we extend the concept of the SP-OMA to dual-polarization IQ modulators. A novel phase retrieval algorithm with an alternating minimization procedure is proposed for identifying the frequency-dependent IQ imbalances on both polarization channels simultaneously from a single photodetector output. The validity and feasibility of the proposed SP-OMA for a dual-polarization IQ modulator are demonstrated numerically and experimentally with a 63.25-Gbaud DP-16QAM signal.

Room temperature bonding is essential for wafer-level heterogeneous integration of LiNbO 3 -on-insulator (LNOI) photonics to Si. This paper reports first demonstration of thin film LNOI optical modulator arrays fabricated on Si wafer by room-temperature wafer bonding with Si nanoadhesive layer.

This publisher’s note contains corrections to J. Opt. Commun. Netw. 14, 595 (2022)JOCNBB1943-062010.1364/JOCN.455171.

In this study, InAs multiple-stacked quantum dot lasers were investigated in the 1.55 μm band using the Bi surfactant effect. The Bi surfactant effect increased the size of the quantum dot and changed the emission wavelength from 1522 to 1554 nm. Moreover, the surfactant effect enhanced the internal quantum efficiency of the fabricated broad-area laser from 33% to 54%.

The development of a system facilitating the convergence of millimeter-wave and optical systems is highly desirable to realize 5G/beyond 5G mobile communication. However, such broad-bandwidth signals cannot be easily transmitted using a long optical fiber owing to the optical fiber chromatic dispersion effect. This paper reports upon the realization of a high-speed millimeter-wave radio-over-fiber signal transmission by using an optical single-sideband (SSB) modulation scheme. The combination of an optical intensity modulator and optical filter can provide the optical SSB signals with an automatic bias controller. The IEEE802.11ad-compliant packet streams are successfully transmitted and converted into 105 GHz millimeter-wave signals. The system can generate and transmit a packet in 16-QAM under an error vector magnitude of 4.8% at a frequency of 104.77 GHz.

Balloon enteroscopy-assisted endoscopic retrograde cholangiography (BEA-ERC) is useful and feasible in adults with pancreatobiliary diseases, but its efficacy and safety have not been established in pediatric patients. We compared the success rate and safety of BEA-ERC between adults and pediatric patients. This single-center retrospective study reviewed 348 patients (pediatric: 57, adult: 291) with surgically altered gastrointestinal anatomies who underwent BEA-ERC for biliary disorders from January 2007 to December 2019. The success rate of reaching the anastomosis or duodenal papilla was significantly lower in pediatric patients than in adult patients (66.7% vs. 88.0%, p &lt, 0.01). The clinical success rate was also significantly lower in pediatric patients (64.9% vs. 80.4%, p = 0.014). The rate of adverse events was significantly higher in pediatric patients than in adults (14.2% vs. 7.7%, p = 0.037). However, if the anastomotic sites were reached in pediatric patients, the treatment was highly successful (97.3%). The time of reaching target site was significantly longer in pediatric patients than in adult patients. This study shows that BEA-ERC in pediatric patients is more difficult than that in adult patients. However, in patients where the balloon enteroscope was advanced to the anastomosis, clinical outcomes comparable to those in adults can be achieved.

Autoimmune pancreatitis (AIP), which is characterized by pancreatic enlargement and irregular narrowing of the main pancreatic duct, is difficult to differentiate from malignancy. The irregular narrowing of the pancreatic duct, which can be detected via endoscopic retrograde cholangiopancreatography, is a characteristic feature of AIP; however, distinguishing between localized AIP and pancreatic cancer based on pancreatic duct imaging is difficult. This study overviews the efficacy of endoscopic ultrasound (EUS)-guided pancreatic sampling for the histopathological diagnosis of AIP. Recent enhancements in needle biopsy methodologies and technologies have contributed to improvement in the diagnostic efficacy of this technique. The guidance provided in this study for the histological diagnosis of AIP is anticipated to further advance in the histopathological diagnosis of AIP using EUS-guided pancreatic sampling.

The histological diagnosis of type 1 autoimmune pancreatitis (AIP) based on the findings obtained by an endoscopic ultrasound-guided fine needle biopsy (EUS-FNB) is feasible, but the diagnostic consistency of this method has not been confirmed. We determined the interobserver agreement among 20 pathologists regarding the diagnosis of type 1 AIP, including the distinction from pancreatic ductal adenocarcinoma (PDAC) using large tissue samples obtained by EUS-FNB. After guidance for diagnosing AIP with biopsy tissues was provided, a round 2 was performed. The median sensitivity and specificity for diagnosing PDAC vs. non-neoplastic diseases were 95.2% and 100%, respectively. In groups of specialists (n = 7) and the generalists (n = 13), Fleiss' к-values increased from 0.886 to 0.958 and from 0.750 to 0.816 in round 2. The concordance was fair or moderate for obliterative phlebitis and storiform fibrosis but slight for ductal lesion of type 1 AIP. Discordant results were due to ambiguous findings and biopsy tissue limitations. Among the specialists, the ratio of cases with perfect agreement regarding the presence of storiform fibrosis increased in round 2, but agreement regarding obliterative phlebitis or ductal lesions was not improved. Although the histological definite diagnosis of type 1 AIP was achieved by most observers in 60% of the cases, the confidence levels varied. Because some ambiguities exist, the histological diagnostic levels based on the diagnostic criteria of type 1 AIP should not be taken for granted. Guidance is effective for improving accurate PDAC diagnoses (notably by recognizing acinar-ductal metaplasia) and for evaluating storiform fibrosis.