Role of endoscopic ultrasound in the characterization of solid pseudopapillary neoplasm of the pancreas

BACKGROUND Solid pseudopapillary neoplasm(SPN)is an uncommon pathology of the pancreas with unpredictable malignant potential.Endoscopic ultrasound(EUS)assessment plays a vital role in lesion characterization and confirmation of the tissue diagnosis.However,there is a paucity of data regarding the imaging assessment of these lesions.AIM To determine the characteristic EUS features of SPN and define its role in preoperative assessment.METHODS This was an international,multicenter,retrospective,observational study of prospective cohorts from 7 large hepatopancreaticobiliary centers.All cases with postoperative histology of SPN were included in the study.Data collected included clinical,biochemical,histological and EUS characteristics.RESULTS One hundred and six patients with the diagnosis of SPN were included.The mean age was 26 years(range 9 to 70 years),with female predominance(89.6%).The most frequent clinical presentation was abdominal pain(80/106;75.5%).The mean diameter of the lesion was 53.7 mm(range 15 to 130 mm),with the slight predominant location in the head of the pancreas(44/106;41.5%).The majority of lesions presented with solid imaging features(59/106;55.7%)although 33.0%(35/106)had mixed solid/cystic characteristics and 11.3%(12/106)had cystic morphology.Calcification was observed in only 4(3.8%)cases.Main pancreatic duct dilation was uncommon,evident in only 2 cases(1.9%),whilst common bile duct dilation was observed in 5(11.3%)cases.One patient demonstrated a double duct sign at presentation.Elastography and Doppler evaluation demonstrated inconsistent appearances with no emergence of a predictable pattern.EUS guided biopsy was performed using three different types of needles:Fine needle aspiration(67/106;63.2%),fine needle biopsy(37/106;34.9%),and Sonar Trucut(2/106;1.9%).The diagnosis was conclusive in 103(97.2%)cases.Ninety-seven patients were treated surgically(91.5%)and the post-surgical SPN diagnosis was confirmed in all cases.During the 2-year follow-up period,no recurrence was observed.CONCLUSION SPN presented primarily as a solid lesion on endosonographic assessment.The lesion tended to be located in the head or body of the pancreas.There was no consistent characteristic pattern apparent on either elastography or Doppler assessment.Similarly SPN did not frequently cause stricture of the pancreatic duct or common bile duct.Importantly,we confirmed that EUS-guided biopsy was an efficient and safe diagnostic tool.The needle type used does not appear to have a significant impact on the diagnostic yield.Overall SPN remains a challenging diagnosis based on EUS imaging with no pathognomonic features.EUS guided biopsy remains the gold standard in establishing the diagnosis.

Transrectal ultrasonography in infertile patients with persistently elevated bacteriospermia

Aim： To identify and define prostate and seminal vesicle abnormalities in patients with chronic male accessory gland infection （MAGI） who failed to respond to antibacterial treatment. Methods： We selected 67 consecutive patients with MAGI and persistently elevated bacteriospermia （≥ 10^6 colony forming units [CFU]/mL） after three antibiotic courses. Fourteen infertile patients with initial chronic microbial （≥ 10^6 CFU/mL） MAGI who responded to antibacterial treatment （〈 10^3 CFU/mL） served as a control group. All patients and controls underwent transrectal ultrasonography （TRUS） scans and semen analysis. Patients with low seminal plasma volume （〈 1.5 mL） underwent both preejaculatory and post-ejaculatory TRUS examination. Results： TRUS revealed multiple abnormalities indicative of： （i） bilaterally extended prostato-vesiculitis （group A： 52 cases, 77.6%） （nine of these patients also had micro-emphysematous prostate abscess）; and （ii） prostato-vesiculitis with unilateral or bilateral sub-obstruction of the ejaculatory ducts （group B： 15 cases, 22.4%）. Mean sperm concentration, total sperm number, ejaculate volume and pH value were significantly higher in group A than in group B. In addition, sperm forward motility and the percentage of normal forms were significantly worse than in controls, whereas leukocyte concentration was significantly higher in group A. Group B patients had all sperm parameters, but their pH values, significantly different from those of controls. Conclusion： Although antibiotic therapy is considered suitable when microbial MAGI is suspected, it is impossible to account for a poor response to antibiotics merely on the basis of conventional criteria （clinical history, physical and ejaculate signs）. Thus, TRUS may be helpful in the follow-up of these patients.

Simulation and feature analysis for gas emboli Doppler ultrasound signals

The purpose of this study is to establish the simulation model of the gas emboli by analyzing reasons for features of gas emboli Doppler ultrasound signals. It is useful for the further classification of the solid emboli and gas emboli. First, the model of the radiation force and the drag force is used to calculate forces acting on the gas emboli. Second, the acceleration of the gas emboli is calculated in both the radial direction and the axial direction of the vessel, which is used to calculate the trajectory of the gas emboli in the vessel. Finally, the computer simulation model is established for the gas emboli. Doppler ultrasound signals of the gas emboli and the solid emboli are generated in the simulation experiment. Experimental results show that compared with the solid emboli, the gas emboli acted by the radiation force and the drag force will result in the frequency-domain broaden in the Doppler spectrogram. When the gas emboli circulate from the low speed area to the high speed one and then from the high speed area back to the low speed one, a ＂V＂ shape will be shown in the spectrogram of gas emboli signals. When the gas emboli circulate from the low speed area to the high speed one or from the high speed area to the low speed one, a diagonal shape will be shown for gas emboli signals. It is also shown that features of simulated gas emboli signals match with those of gas emboli signals sampled from clinic. All demonstrate that the simulation method of the gas emboli is reasonable.