A Novel High-Visibility Radiopaque Tantalum Marker for Biliary Self-Expandable Metal Stents

BACKGROUND/AIMS: Radiopaque metal markers are required to improve X-ray absorption by self-expandable metal stents (SEMSs) to enable precise stent placement. A new tantalum radiopaque marker was recently developed using an ultrasonic spray technique. The aim of the present study was to evaluate the safety and visibility of tantalum markers. METHODS: A total of three beagle dogs were used for a gastrointestinal tract absorption test. Five tantalum markers were placed in the stomach of each dog endoscopically. Excreted tantalum markers were collected, and their weights were compared to the original weights. In radiopacity tests, marker radiopacities on X-ray images were quantified using ImageJ software and compared with those of commercially available metal markers. Finally, the radiographic images of six patients who underwent biliary SEMS placement using tantalum marker Nitinol SEMSs (n=3) or gold marker Nitinol SEMSs (n=3) were compared with respect to marker brightness on fluoroscopic images. RESULTS: Absorption testing showed that the marker structures and weights were unaffected. Radiopacity tests showed that the mean brightness and total brightness scores were greater for tantalum markers (226.22 and 757, respectively) than for gold (A, 209 and 355, respectively; B, 204.96 and 394, respectively; C, 194.34 and 281, respectively) or platinum markers (D, 203.6 and 98, respectively). On fluoroscopic images, tantalum markers had higher brightness and total brightness scores (41.47 and 497.67, respectively) in human bile ducts than gold markers (28.37 and 227, respectively). CONCLUSIONS: Tantalum markers were found to be more visible than other commercially available markers in X-ray images and to be resistant to gastrointestinal absorption.

Does Bicycle Riding Impact the Development of Lower Urinary Tract Symptoms and Sexual Dysfunction in Men?

PURPOSE: This study was designed to determine whether men who engaged in recreational bicycle riding are more likely to be affected by lower urinary tract symptoms (LUTS) and sexual dysfunction than are man who exercised by amateur marathon running with less perineal impact. MATERIALS AND METHODS: A total of 22 healthy male amateur bicyclists and 17 healthy male amateur marathoners were enrolled in the study. We evaluated questionnaires including the International Prostate Symptom Score (IPSS) and the International Index of Erectile Function (IIEF), serum prostate-specific antigen (PSA), uroflowmetric values, postvoid residual (PVR) urine volume, and transrectal ultrasound of the prostate in all subjects. We also compared the prevalence of urination disorders (UD) and erectile dysfunction (ED). RESULTS: There were no significant differences between the two groups in age, body mass index, comorbidities, or exercise habits (p>0.05). Mean total and subscale scores of the IPSS and IIEF and the prevalence of UD (8/22 vs. 4/17, p=0.494) and ED (11/22 vs. 10/17, p=0.748) were not significantly different between the two groups. Also, there were no significant differences between the two groups in uroflowmetric parameters such as peak urinary flow rates, voided urine volume, PVR urine volume, prostate volume, or serum PSA level. CONCLUSIONS: Bicycle riding seems to have no measurable hazardous effect on voiding function or sexual function in men who cycled recreationally.

Unusual Presentation of Bilateral Adrenocortical Carcinoma Mimicking Adrenal Metastasis

A 75-year-old female visited our hospital with bilateral adrenal masses that were detected incidentally during lumbar spine magnetic resonance imaging (MRI) for the evaluation of radiating flank pain. Consecutive computed tomography and MRI revealed bilateral adrenal masses with no evidence of lymph node enlargement or local invasion; 2[(18)F]fluoro-2-deoxyglucose (FDG)-positron emission tomography showed an intense FDG accumulation in both adrenal glands without abnormal FDG uptake in extra-adrenal regions. The laboratory test results were within normal ranges. We performed a bilateral adrenalectomy. The pathologic diagnosis of both adrenal masses was consistent with adrenocortical carcinoma. The patient recovered well with no complications.

A Study on Fatigue Characteristic of Stent Using Finite Element Analysis / 의학물리

Stents are frequently used throughout the human body. They keep pathways open in vascular or nonvascular duct for a long time. Therefore its stability is very important factor. In recent years, aconsiderable amount of research has been carried out in order to estimate mechanical properties of the stent such as expansion pressure behavior, radial recoil and longitudinal recoil using FEM (Finite element analyses). However, published works on simulation of stent fatigue behavior using FEM are relatively rare. In this paper, a nonlinear finite-element method was employed to analyses the compression of a stent using external pressure and fatigue behavior. Finite element analyses for the stent system were performed using NASTRAN FX. In conclusion this paper shows how the stent is behaved in the body, and its fatigue behavior.

A Study of Drug Content and Cell Cytotoxicity of Paclitaxel-eluting Stents Coated with Various Biopolymer / 의학물리

In this study, the paclitaxel eluting stent (PES) was prepared by coating a biliary stent with paclitaxel using various biopolymer such as poly (vinyl acetate) (PVAc), poly (lactic-co-glycolic acid) (PLGA), Silicone rubber for restenosis prevention in gastrointestinal disease by a dip-coating method. Drug contents of PES were increased as surface area of stent, concentration and molecular weight of coating polymer increase. In 1H-NMR specta, we know that drug did not change by confirming specific peaks of paclitaxel in PES. As shown in SEM image, PES prepared using various biopolymer is coated clearly and regularly except Silicone rubber coating polymer. In in vitro cell cytotoxicity test, bare stent showed low cytotoxic effect against CT-26 colon carcinoma cell line on 3 day. However, PES coated with PLGA 502H showed the highest cytotoxicity because PLGA 502H is biodegradable polymer and has less molecular weight than other coating polymer. These results suggest that PES coated various biopolymer can be prevented restenosis in gastrointestinal disease.