Catheter Segments Research Articles

Development and validation of an in vitro model to study thrombin generation on the surface of catheters in platelet-poor and platelet-rich plasma

IntroductionCoagulation activation on medical devices remains a significant problem as it can lead to dramatic thromboembolic complications. Understanding its poorly described mechanisms and finding optimal pharmacological prevention means is crucial to improve patient safety. MethodsWe developed an in vitro model to study thrombin generation (TG) initiated by the contact of plasma with the surface of catheters. Interventional cardiology catheters were cut into segments and inserted in the bottom of multi-well plates; TG was then measured with the calibrated automated thrombogram (CAT). Model performance (analytical, intra- and inter-individual variability) was investigated and compared with activation of thrombin generation by tissue factor (TF) or contact pathway activator (ellagic acid), in the presence (PRP) and absence (PPP) of platelets. Model response to unfractionated heparin (UFH) was also assessed. ResultsTG was greater when measured in presence of catheter segments, compared to conditions without activators. The analytical variability of the model was good (CV ≤ 5 %), both with PPP and PRP. Intra-individual variability was between 15 and 30 % with PPP and between 10 and 15 % with PRP. Inter-individual variability was between 15 and 30 % with both kinds of plasma samples. The analytical performance of the catheter-initiated TG model was equivalent to that observed when TG was initiated with TF or ellagic acid. Catheter-initiated TG was measurable until 0.1 IU/mL UFH with PPP and until 1.0 IU/mL UFH with PRP, highlighting the crucial requirement of platelets. ConclusionOur model is suitable for studying TG initiated with catheters. Inhibition of TG by UFH is overestimated in the absence of platelets.

Rapid multi-catheter segmentation for magnetic resonance image-guided catheter-based interventions.

Magnetic resonance imaging (MRI) is the gold standard for delineating cancerous lesions in soft tissue. Catheter-based interventions require the accurate placement of multiple long, flexible catheters at the target site. The manual segmentation of catheters in MR images is a challenging and time-consuming task. There is a need for automated catheter segmentation to improve the efficiency of MR-guided procedures. To develop and assess a machine learning algorithm for the detection of multiple catheters in magnetic resonance images used during catheter-based interventions. In this work, a 3D U-Net was trained to retrospectively segment catheters in scans acquired during clinical MR-guided high dose rate (HDR) prostate brachytherapy cases. To assess confidence in segmentation, multiple AI models were trained. On clinical test cases, average segmentation results were used to plan the brachytherapy delivery. Dosimetric parameters were compared to the original clinical plan. Data was obtained from 35 patients who underwent HDR prostate brachytherapy for focal disease with a total of 214 image volumes. 185 image volumes from 30 patients were used for training using a five-fold cross validation split to divide the data for training and validation. To generate confidence measures of segmentation accuracy, five trained models were generated. The remaining five patients (29 volumes) were used to test the performance of the trained model by comparison to manual segmentations of three independent observers and assessment of dosimetric impact on the final clinical brachytherapy plans. The network successfully identified 95% of catheters in the test set at a rate of 0.89s per volume. The multi-model method identified the small number of cases where AI segmentation of individual catheters was poor, flagging the need for user input. AI-based segmentation performed as well as segmentations by independent observers. Plan dosimetry using AI-segmented catheters was comparable to the original plan. The vast majority of catheters were accurately identified by AI segmentation, with minimal impact on plan outcomes. The use of multiple AI models provided confidence in the segmentation accuracy and identified catheter segmentations that required further manual assessment. Real-time AI catheter segmentation can be used during MR-guided insertions to assess deflections and for rapid planning of prostate brachytherapy.

Broken epidural catheter: individualize your management

BackgroundEpidural anaesthesia is one of the most used neuraxial anaesthesia techniques. It has been utilized as the principal anaesthesia modality involving lower limb surgery. Breakage of epidural catheters is an unusual occurrence whose subsequent therapy lacks uniformity due to the absence of a consensus and defined standards.Case presentationA 39-year-old male with no comorbidities was scheduled for right lower limb reconstruction surgery due to non-union of the tibia. Combined spinal-epidural anaesthesia was planned. During epidural catheter insertion, there was difficulty threading the catheter, and upon its removal, a long segment of catheter (8 cm) was left inside the body. Following informed consent from the patient, the retained fragment was surgically extracted in the same sitting under general anaesthesia.ConclusionsEven when faced with such a circumstance, it is best to explore surgically and remove a long segment broken catheter to allay patient anxiety.

Histidine-rich glycoprotein attenuates catheter thrombosis.

Factor XII (FXII) knockdown attenuates catheter thrombosis in rabbits. Because histidine-rich glycoprotein (HRG) modulates FXIIa activity, we hypothesized that HRG depletion would promote catheter thrombosis. To test this, rabbits were given either antisense oligonucleotides (ASOs) against HRG or FXII, a control ASO, or saline. The activated partial thromboplastin time (aPTT), prothrombin time (PT), and catheter-induced thrombin generation were determined in blood collected before and after treatment. Compared with the controls, the HRG- and FXII-directed ASOs reduced hepatic messenger RNA and plasma levels of HRG and FXII, respectively, by >90%. Although HRG knockdown shortened the aPTT by 2.5 fold, FXII knockdown prolonged it by fourfold; neither of the ASOs affected the PT. Catheter segments shortened the lag time and increased peak thrombin in the plasma from control rabbits; effects were significantly enhanced and attenuated in the plasma from rabbits given the HRG- and FXII-directed ASOs, respectively. Catheters were then inserted into the right external jugular vein of the rabbits, and the time for catheter occlusion was determined. The catheter occlusion times with the control ASO or saline were 62± 8minutes and 60± 11minutes, respectively. The occlusion time was significantly reduced to 34± 9minutes, with HRG knockdown and significantly prolonged to 128± 19minutes with FXII knockdown. HRG levels are decreased with sepsis or cancer, and such patients are prone to catheter thrombosis. Because HRG modulates catheter thrombosis, our findings suggest that HRG supplementation may prevent this problem.

Automated catheter segmentation and tip detection in cerebral angiography with topology-aware geometric deep learning

BackgroundVisual perception of catheters and guidewires on x-ray fluoroscopy is essential for neurointervention. Endovascular robots with teleoperation capabilities are being developed, but they cannot ‘see’ intravascular devices, which precludes artificial...

#6572 FLUORINATED GRAPHENE REDUCES PLATELET ACTIVATION AND ADHESION ON HEMODIALYSIS CATHETER

Abstract Background and Aims Catheter thrombosis remains one of the major complications of hemodialysis. Superhydrophobic surfaces are suggested to be capable of creating an energy barrier that prevents cells and proteins from contacting with the catheter surface directly, making catheter less thrombotic. Fluorinated graphene (FG) is a superhydrophobic material. It has been applied to create self-cleaning surfaces. It also shows good biocompatibility. Based on these features of FG, we prepared an FG coating on hemodialysis catheter attempting to reduce clinical thrombotic events. Method FG suspension was made in a solution of 95 wt.% ethanol, 5 wt.% deionized water and 3 wt.% 1H,1H,2H,2H-Perfluorooctyltriethoxysilane (POTS, C14H15F17O3Si). Immediately following the plasma activation, catheter segments of 1 cm²(Gamcath, GDHK1325) were spray coated with FG suspension both inside and outside the catheter lumen. Samples were air-dried for later use. We tested the hemolysis rate, platelet activation and adhesion performances, and the partial thromboplastin time (PTT) of the FG-coated samples. Test for hemolysis was performed with FG-coated catheter and the isotonic extract of the FG coating in direct contact with fresh rabbit blood respectively. Platelet activation and adhesion was performed according to the ASTM F2888-19 standard and also assessed by scanning electron microscope. PTT assay was performed according to the ASTM F2382-18 standard. Results FG-coated catheter is hydrophobic and shows a water contact angle of 150° (Figure 1a). It reduced 83.5% of platelet adhesion per 100 μm² catheter surface area and avoided 35.86% of platelet loss from the blood when compared to uncoated catheter (Figure 1b, 1c). It has a hemolysis rate of less than 2% in both direct blood contact test and the extract test (Figure 1d). The PTT of FG-coated sample was 88.92±1.31s versus 83.03±9.49s of the uncoated catheter yet with no statistical significance (P>0.05) (Figure 1e). Conclusion FG coating has great hemocompatibility. Though no significant improvement was observed in the PTT assay, FG coating still significantly reduced the adherent and activated platelet on catheter, which seems promising to reduce thrombotic events. Yet, more tests needed to be performed, and the antithrombotic ability of FG coating in the fluid state needs to be further confirmed in the following study.

Use of semi-synthetic data for catheter segmentation improvement.

In the era of data-driven machine learning algorithms, data is the new oil. For the most optimal results, datasets should be large, heterogeneous and, crucially, correctly labeled. However, data collection and labeling are time-consuming and labor-intensive processes. In the field of medical device segmentation, present during minimally invasive surgery, this leads to a lack of informative data. Motivated by this drawback, we developed an algorithm generating semi-synthetic images based on real ones. The concept of this algorithm is to place a randomly shaped catheter in an empty heart cavity, where the shape of the catheter is generated by forward kinematics of continuum robots. Having implemented the proposed algorithm, we generated new images of heart cavities with various artificial catheters. We compared the results of deep neural networks trained purely on real datasets with respect to networks trained on both real and semi-synthetic datasets, highlighting that semi-synthetic data improves catheter segmentation accuracy. A modified U-Net trained on combined datasets performed the segmentation with a Dice similarity coefficient of 92.6±2.2%, while the same model trained only on real images achieved a Dice similarity coefficient of 86.5±3.6%. Therefore, using semi-synthetic data allows for the decrease of accuracy spread, improves model generalization, reduces subjectivity, shortens the labeling routine, increases the number of samples, and improves the heterogeneity.

A fragmented segment of a central venous catheter caused delayed ventricular fibrillation: a case report

BackgroundCentral venous port systems may be safely used for chemotherapy of patients with cancer, but several complications may occur associated with their use.Case presentationAn 83-year-old man with heat stroke was transferred to our emergency department, where he was treated and became able to eat on the same day. He had been fit and healthy, except for colorectomy and chemotherapy using a central venous access port placed in the right upper jugular vein 8 years ago. The next day, he suddenly had ventricular fibrillation. Cardiopulmonary resuscitation was successful. Emergency coronary angiography showed a catheter-like foreign body in the coronary sinus. Physicians failed to remove the foreign body using catheter therapy, and ventricular fibrillation occurred repeatedly. After induction of general anesthesia, the fractured catheter was removed surgically. Postoperative course was uneventful.ConclusionsA fragmented segment of a catheter may suddenly cause ventricular fibrillation years later.

Domestic LED bulb induced photodynamic effect of Toluidine Blue O-embedded silicone catheters against urinary tract infection

BackgroundNovel combination of Toluidine Blue O (TBO) embedded silicone catheter with domestic/household LED bulb has a potential in clinical infection such as prevention of multi drug resistant catheter-associated urinary tract infections (CAUTIs) through photodynamic therapy. Material and methodsPreliminarily, TBO was entrapped into silicone catheter by swell-encapsulation-shrink method. Further, in vitro study was carried out to check the antimicrobial photodynamic efficacy of TBO with domestic/household LED light. Antibiofilm activity was evaluated by scanning electron microscopy. ResultsThe results showed that these modified TBO embedded silicone catheters showed significant antimicrobial and antibiofilm activity against vancomycin resistant Staphylococcus aureus VRSA. Small piece (1 cm) of TBO-embedded silicone catheter (700 µM) showed 6 log10 reduction in the viable count when exposed for only 5 min of domestic/household LED bulb, while 1 cm piece of 500 µM and 700 µM concentration of TBO-embedded catheter eradicated all bacterial load when exposed to 15 min of light. Segment of medical grade TBO-embedded silicone catheters were used to carry out investigation of reactive oxygen species generation mainly singlet oxygen that contributes to type II phototoxicity. ConclusionThese modified catheter provides cost effective, easy to manage and less time consuming therapy to eliminate CAUTIs.

A robust localization approach for Percutaneous Nephrolithotomy (PCNL): A single-center retrospective study.

Percutaneous Nephrolithotomy (PCNL) represents the gold standard treatment method for cases with large kidney stones. As a critical step in performing PCNL, the procedure of establishing a safe and accurate nephrostomy tract will dramatically impact the treatment quality of patients with large-sized kidney stones. This work attempts to describe a new and improved process of establishing an accurate nephrostomy tract and clinically evaluate the effectiveness and safeness of this proposed methodology. This work represents a retrospective single-center study carried out between August 2013 and November 2019. The collected samples consist of 937 patients who were operated on using PCNL coupled with our proposed procedure. Briefly, a preoperative B-ultrasonography was firstly performed to decide the puncture point in a simulated surgical position where was marked with ureteral catheter segments (2-3 cm). A computed tomography (CT) scan was followed to correct the anchor points in the simulated surgical position. After this, an accurate puncture operation was performed under the real-time guidance of intraoperative B ultrasound. Examining this study, 851 subjects with renal stones and 86 subjects with ureteropelvic junction stones were included for the PCNL operation project. All samples were grouped with Guy's grading system: grade I, II, III, and IV patients there were 0.00%, 42.69%, 51.01%, and 6.30%, respectively. Among these patients, the average age was 48.49 ± 10.80 years old, with a male to female ratio of around 1.73:1. This study showed that our developed method warrants an accurate and safe PCNL operation that involves the process of establishing the nephrostomy tract. Other advantageous attributes of this new PCNL process include negligible radiation exposure, lesser complications, and low failure rates. More importantly, this new localization approach is particularly attractive for hospitals that are new to the field of adopting PCNL considering its safeness, effectiveness, and learnability.

In vitro and in vivo evaluation of DNase I in reinstating antibiotic efficacy against Klebsiella pneumoniae biofilms.

Klebsiella pneumoniae is an opportunistic pathogen associated with biofilm-based infections, which are intrinsically antibiotic resistant. Extracellular DNA plays a crucial role in biofilm formation and self-defence, with nucleases being proposed as promising agents for biofilm disruption. This study evaluated the in vitro and in vivo efficacy of DNase I in improving the activity of cefotaxime, amikacin, and ciprofloxacin against K. pneumoniae biofilms. K. pneumoniae ATCC 700603 and a clinical isolate from catheter-related bloodstream infection were cultured for biofilm formation on microtiter plates, and the antibiofilm activity of the antibiotics (0.03-64 mg/L), with or without bovine pancreatic DNase I (1-32 mg/L) was determined by XTT dye reduction test and viable counting. The effect of ciprofloxacin (2 mg/L) and DNase I (16 mg/L) was further evaluated in vitro on 1-cm-long silicon catheter segments, and in a mouse model of subcutaneous catheter-associated infection. Combination with DNase I did not improve the biofilm-preventive capacity of the three antibiotics or the biofilm-eradicating capacity of cefotaxime and amikacin. The biofilm-eradicating capacity of ciprofloxacin was increased by 8-fold and 4-fold in K. pneumoniae ATCC 700603 and clinical isolate, respectively, with DNase I. The combination therapy caused 99% reduction in biofilm biomass in the mouse model.

Rivaroxaban and apixaban are less effective than enoxaparin for the prevention of catheter-induced clotting in vitro

BackgroundCentral venous catheters are prone to clotting, particularly in patients with cancer. Although low-molecular-weight heparin and direct oral anticoagulants, such as apixaban and rivaroxaban, have been evaluated for the prevention of catheter thrombosis, their efficacy remains uncertain. ObjectivesCompare apixaban and rivaroxaban with enoxaparin for the prevention of catheter-induced clotting in vitro. MethodsTo address this uncertainty, we used a well-established microplate-based assay to compare the effects of enoxaparin, apixaban, and rivaroxaban on catheter-induced thrombosis and thrombin generation in human plasma. ResultsConsistent with our previous findings, catheter segments shortened the clotting time and promoted thrombin generation. When compared at concentrations with similar anti-factor Xa activity as enoxaparin, apixaban and rivaroxaban were >20-fold less potent than enoxaparin for the prevention of catheter-induced clotting and thrombin generation. ConclusionThe prevention of catheter thrombosis in patients with cancer is challenging. Clinical trials are needed to compare the efficacy of low-molecular-weight heparin with that of direct oral anticoagulants both for the prevention and treatment of catheter thrombosis.

Characterization and anti-biofilm activity of bacteriophages against urinary tract Enterococcus faecalis isolates

Strong biofilm-forming Enterococcus feacalis urinary tract pathogens (n = 35) were used to determine the lytic spectrum of six bacteriophages isolated from sewage samples. Only 17 Enterococcus feacalis isolates gave lytic zones with the tested bacteriophages from which five isolates were susceptible to all of them. The isolated enterococcal phages are characterized by wide range of thermal (30–90 °C) and pH (3–10) stability. They belong to order Caudovirales, from which four bacteriophages (EPA, EPB, EPD, EPF) belong to family Myoviridae and two (EPC, EPE) belong to family Siphoviridae. In addition, they have promising antibiofilm activity against the tested strong-forming biofilm E. faecalis isolates. The enterococcal phages reduced the formed and preformed biofilms to a range of 38.02–45.7% and 71.0–80.0%, respectively, as compared to the control. The same promising activities were obtained on studying the anti-adherent effect of the tested bacteriophages on the adherence of bacterial cells to the surface of urinary catheter segments. They reduced the number of adherent cells to a range of 30.8–43.8% and eradicated the pre-adherent cells to a range of 48.2–71.1%, as compared to the control. Overall, the obtained promising antibiofilm activity makes these phages good candidates for application in preventing and treating biofilm associated Enterococcus faecalis infections.

Development of deep learning segmentation models for coronary X-ray angiography: Quality assessment by a new global segmentation score and comparison with human performance

Introduction and objectivesAlthough automatic artificial intelligence (AI) coronary angiography (CAG) segmentation is arguably the first step toward future clinical application, it is underexplored. We aimed to (1) develop AI models for CAG segmentation and (2) assess the results using similarity scores and a set of criteria defined by expert physicians. MethodsPatients undergoing CAG were randomly selected in a retrospective study at a single center. Per incidence, an ideal frame was segmented, forming a baseline human dataset (BH), used for training a baseline AI model (BAI). Enhanced human segmentation (EH) was created by combining the best of both. An enhanced AI model (EAI) was trained using the EH. Results were assessed by experts using 11 weighted criteria, combined into a Global Segmentation Score (GSS: 0–100 points). Generalized Dice Score (GDS) and Dice Similarity Coefficient (DSC) were also used for AI models assessment. Results1664 processed images were generated. GSS for BH, EH, BAI and EAI were 96.9+/-5.7; 98.9+/-3.1; 86.1+/-10.1 and 90+/-7.6, respectively (95% confidence interval, p<0.001 for both paired and global differences). The GDS for the BAI and EAI was 0.9234±0.0361 and 0.9348±0.0284, respectively. The DSC for the coronary tree was 0.8904±0.0464 and 0.9134±0.0410 for the BAI and EAI, respectively. The EAI outperformed the BAI in all coronary segmentation tasks, but performed less well in some catheter segmentation tasks. ConclusionsWe successfully developed AI models capable of CAG segmentation, with good performance as assessed by all scores.

Weakly-supervised learning for catheter segmentation in 3D frustum ultrasound.

Accurate and efficient catheter segmentation in 3D ultrasound (US) is essential for ultrasound-guided cardiac interventions. State-of-the-art segmentation algorithms, based on convolutional neural networks (CNNs), suffer from high computational cost and large 3D data size for GPU implementation, which are far from satisfactory for real-time applications. In this paper, we propose a novel approach for efficient catheter segmentation in 3D US. Instead of using Cartesian US, our approach performs catheter segmentation in Frustum US (i.e., the US data before scan conversion). Compared to Cartesian US, Frustum US has a much smaller volume size, therefore the catheter can be segmented more efficiently in Frustum US. However, annotating the irregular and deformed Frustum images is challenging, and it is laborious to obtain the voxel-level annotation. To address this, we propose a weakly supervised learning framework, which requires only bounding-box annotations. The labels of the voxels are generated by incorporating class activation maps with line filtering, which are iteratively updated during the training cycles. Our experimental results show that, compared to Cartesian US, the catheter can be segmented much more efficiently in Frustum US (i.e., 0.25s per volume) with better accuracy. Extensive experiments also validate the effectiveness of the proposed weakly supervised learning method.

A Technique for Witzel Tunnel Catheter Drainage of the Biliary and Pancreatic Anastomosis of a Whipple Procedure

Introduction: Stenting the pancreatic and biliary anastomoses in a Whipple procedure has been shown to lower the rate of anastomotic leak. Method: We have identified a combined biliary and pancreatic ductal external drainage catheter/stent to decompress the small bowel limb and both anastomoses. The single catheter is a combination of a red Robinson catheter and a silastic pediatric feeding tube each of appropriate size for the duct they are draining. The silastic feeding tube is inserted into the lumen of the red rubber catheter though a small tight fenestration in the elastic external segment of the red catheter and exits the red rubber catheter through a similar fenestration at the level of the hepatico-jejunostomy. The silastic feeding tube is then advanced into the pancreatic duct where it is secured to the small bowel mucosa with a fine absorbable suture to prevent dislodgement. The combined tubes then exits the small bowel “Whipple limb” though a Witzel tunnel. The small bowel is secured to the right upper quadrant abdominal wall with several interrupted 3-0 Vicryl sutures. Results: Our technique offers several advantages. It’s a more durable way of stenting the two anastomoses and prevents stent migration. It provides an opportunity to study the two anastomosis via contrast administration. The witzel tunnel and the anchoring of the jejunal limb to the lateral abdominal wall opens the door for several IR/endoscopic interventions. Conclusion: The use of a combined biliary and pancreatic ductal external drainage catheter/stent system has many theoretical advantages.

Staphylococcal Biofilm on the Surface of Catheters: Electron Microscopy Evaluation of the Inhibition of Biofilm Growth by RNAIII Inhibiting Peptide.

Staphylococcus aureus and coagulase-negative staphylococci (CoNS) have become the main causative agents of medical device-related infections due to their biofilm-forming capability, which protects them from the host’s immune system and from the action of antimicrobials. This study evaluated the ability of RNA III inhibiting peptide (RIP) to inhibit biofilm formation in 10 strains isolated from clinical materials, including one S. aureus strain, two S. epidermidis, two S. haemolyticus, two S. lugdunensis, and one isolate each of the following species: S. warneri, S. hominis, and S. saprophyticus. The isolates were selected from a total of 200 strains evaluated regarding phenotypic biofilm production and the presence and expression of the ica operon. The isolates were cultured in trypticase soy broth with 2% glucose in 96-well polystyrene plates containing catheter segments in the presence and absence of RIP. The catheter segments were observed by scanning electron microscopy. The results showed inhibition of biofilm formation in the presence of RIP in all CoNS isolates; however, RIP did not interfere with biofilm formation by S. aureus. RIP is a promising tool that might be used in the future for the prevention of biofilm-related infections caused by CoNS.

Hemorrhagic abdominal pseudocyst following ventriculoperitoneal shunt: a case report

BackgroundAbdominal cerebrospinal fluid (CSF) pseudocyst is an uncommon but important complication of ventriculoperitoneal (VP) shunts. While individual articles have reported many cases of abdominal CSF pseudocyst following VP shunts, no case of a hemorrhagic abdominal pseudocyst after VP shunts has been reported so far.Case presentationThis article reports a 68-year-old woman with a 4-month history of progressive abdominal pain and distention. She denied any additional symptoms. A VP shunt was performed 15 years earlier to treat idiopathic normal pressure hydrocephalus and no other abdominal surgery was performed. Physical examination revealed an elastic palpable mass in her right lower abdomen, which was dull to percussion. Abdominal computed tomography (CT) scan indicated a large cystic collection of homogenous iso-density fluid in the right lower abdominal region with clear margins. The distal segment of the peritoneal shunt catheter was located within the cystic mass. Abdominal CSF pseudocyst was highly suspected as a diagnosis. Laparoscopic cyst drainage with removal of the whole cystic mass was performed, 15-cm cyst which found with thick walls and organized chronic hematic content. No responsible vessel for the cyst hemorrhage was identified. No further shunt revision was placed. Histological examination showed that the cyst wall consisted of outer fibrous tissue and inner granulation tissue without epithelial lining, and the cystic content was chronic hematoma. The patient had an uneventful postoperative course and remained asymptomatic for 8-mo follow-up.ConclusionTo the best of our knowledge, this is the first report of hemorrhagic onset in the abdominal pseudocyst following VP shunt. Such special condition can accelerate the appearance of clinical signs of the abdominal pseudocyst after VP shunts, and its mechanisms may be similar to the evolution of subdural effusion into chronic subdural hematoma (CSDH).

Synthesize and Segment: Towards Improved Catheter Segmentation via Adversarial Augmentation

Automatic catheter and guidewire segmentation plays an important role in robot-assisted interventions that are guided by fluoroscopy. Existing learning based methods addressing the task of segmentation or tracking are often limited by the scarcity of annotated samples and difficulty in data collection. In the case of deep learning based methods, the demand for large amounts of labeled data further impedes successful application. We propose a synthesize and segment approach with plug in possibilities for segmentation to address this. We show that an adversarially learned image-to-image translation network can synthesize catheters in X-ray fluoroscopy enabling data augmentation in order to alleviate a low data regime. To make realistic synthesized images, we train the translation network via a perceptual loss coupled with similarity constraints. Then existing segmentation networks are used to learn accurate localization of catheters in a semi-supervised setting with the generated images. The empirical results on collected medical datasets show the value of our approach with significant improvements over existing translation baseline methods.

Anti-Biofilm Effect of Octenidine and Polyhexanide on Uropathogenic Biofilm-Producing Bacteria

Background: A catheter allowing a release of antibacterial substances such as antiseptics into the bladder could be a new way of preventing biofilm formation and subsequent catheter-associated urinary tract infections. Methods: Minimal inhibitory and bactericidal concentration (MIC/MBC) determinations in cation-adjusted Mueller-Hinton broth and artificial urine were performed for 4 antiseptics against 3 uropathogenic biofilm producers, Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis. Furthermore, effects of octenidine and polyhexanide against catheter biofilm formation were determined by quantification of biofilm-producing bacteria. Results: Sodium hypochlorite showed MIC/MBC values between 200 and 800 mg/L for all strains tested. Triclosan was efficient against E. coli and P. mirabilis (MIC ≤2.98 mg/L) but ineffective against P. aeruginosa. Octenidine and polyhexanide showed antibacterial activity against all 3 species tested (MIC 1.95–7.8 and 3.9–31.25 mg/L). Both octenidine and polyhexanide were able to prevent biofilm formation on catheter segments in a concentration dependent manner. Furthermore, adding 250 mg/L of each biocide disrupted biofilms formed by E. coli and P. mirabilis, whereas even 500 mg/L was not sufficient to completely destroy P. aeruginosa biofilms. Conclusion: Octenidine- and polyhexanide-containing antiseptics showed a broad effect against typical uropathogenic biofilm producers even in high dilutions. This study provides a basis for further investigation of the potential of octenidine and polyhexanide as prophylaxis or treatment of catheter biofilms.