3D-Printed Osteoinductive Polymeric Scaffolds with Optimized Architecture to Repair a Sheep Metatarsal Critical-Size Bone Defect

The reconstruction of critical-size bone defects in long bones remains a challenge for clinicians. A new osteoinductive medical device is developed here for long bone repair by combining a 3D-printed architectured cylindrical scaffold made of clinical-grade polylactic acid (PLA) with a polyelectrolyte film coating delivering the osteogenic bone morphogenetic protein 2 (BMP-2). This film-coated scaffold is used to repair a sheep metatarsal 25-mm long critical-size bone defect. In vitro and in vivo biocompatibility of the film-coated PLA material is proved according to ISO standards. Scaffold geometry is found to influence BMP-2 incorporation. Bone regeneration is followed using X-ray scans, µCT scans, and histology. It is shown that scaffold internal geometry, notably pore shape, influenced bone regeneration, which is homogenous longitudinally. Scaffolds with cubic pores of ≈870 µm and a low BMP-2 dose of ≈120 µg cm-3 induce the best bone regeneration without any adverse effects. The visual score given by clinicians during animal follow-up is found to be an easy way to predict bone regeneration. This work opens perspectives for a clinical application in personalized bone regeneration.

Myocardial blood flows and reserves on solid state camera: Correlations with coronary history and cardiovascular risk factors

OBJECTIVES

Study designed to test association between stress-induced myocardial blood flow (sMBF), resting MBF (rMBF), and MBF reserve (MFR) and coronary artery disease (CAD) in a population of CAD and non-coronary patients. Secondary objectives were to confront visual analysis and dynamic analysis and to explore potential association between MBF and several cardiovascular risk factors METHODS: A total of 155 patients who underwent dynamic myocardial perfusion imaging on a CZT camera were included. sMBF, rMBF, and MFR were evaluated, and cardiovascular risk was assessed.

RESULTS

Significantly lower total sMBF and MFR were observed in CAD patient vs non-CAD patient. In comparison with visual analysis, lower sMBF were found in pathologic territory, lower rMBF in necrotic territory and lower MFR in necrotic ones. A significant correlation between total sMBF, rMBF and diabetes was found.

CONCLUSION

sMBF and MFR as assessed on CZT gamma-cameras can be used to determine the coronary state. Low total sMBF might be an independent risk factor of coronaropathy. An inverse correlation was suggested between total sMBF and rMBF with diabetes.

Cytocompatibility / Antibacterial Activity Trade-off for Knittable Wet-Spun Chitosan Monofilaments Functionalized by the In Situ Incorporation of Cu2+ and Zn2

The wet spinning of cytocompatible, bioresorbable, and knittable chitosan (CTS) monofilaments would be advantageous for a variety of surgical applications. The complexation capacity of chitosan with Cu²⁺ or Zn²⁺ can be leveraged to enhance its antibacterial activity, but not at the expense of cytocompatibility. In this work, a wet-spinning process was adapted for the in situ incorporation of Cu²⁺ or Zn²⁺ with chitosan dopes to produce monofilaments at different drawing ratios (τ_tot) with various cation/glucosamine molar ratios, evaluated in the fibers (r_Cu,f and r_Zn,f). Cytocompatibility and antibacterial activity of wet-spun monofilaments were, respectively, quantified by in vitro live-dead assays on balb 3T3 and by different evaluations of the proliferation inhibition of Staphylococcus epidermidis (Gram+) and Escherichia coli (Gram-). Knittability was tested by a specific tensile test using a knitting needle and evaluated with an industrial knitting machine. It was found that r_Cu,f = 0.01 and r_Zn,f = 0.03 significantly increase the antibacterial activity without compromising cytocompatibility. Wet spinning with τ_tot = 1.6 allowed the production of knittable CTS-Cu monofilaments, as confirmed by knitting assays under industrial conditions.

Key Role of Personalized Dosimetry in Dose Adjustment for Selective Internal Radiotherapy: Retrospective Study of Patients Treated With 90Y Resin Microspheres

PURPOSE

Selective internal radiotherapy with 90Y microspheres is widely used for the treatment of patients with liver cancer. A dosimetric analysis using the dosimetry software Simplicit90y (Boston Scientific, Natick, MA) was conducted to define doses to the tumor and healthy liver, and to determine a threshold tumor dose that could predict progression-free survival.

METHODS

Patients experiencing hepatocellular carcinoma and treated with 90Y-labeled resin microspheres were included in a retrospective study. The time-to-progression of the target lesions (TTPLs) and overall survival (OS) were evaluated using Kaplan-Meier tests, and this comparison was based on a log-rank test.

RESULTS

Twenty-four procedures for patients with portal vein thrombosis were realized. Median follow-up was 16 months. A threshold tumor dose of 125 Gy was determined with a sensitivity of 89% and a specificity of 100%. For patients with a tumor dose of less than 125 Gy, the median OS was 7.5 months (95% confidence interval [CI], 5-14 months) and the TTPL was 3 months (95% CI, 2-6 months) versus 33 months (95% CI, 22-39 months) and 23 months (95% CI, 7-38 months), respectively, for those with a tumor dose of 125 Gy or more (P = 0.002 and P = 0.0004).

CONCLUSIONS

Personalized dosimetry based on 99mTc-MAA SPECT/CT is predictive of TTPL and OS in patients with hepatocellular carcinoma. Customized dosimetry software is essential to optimize treatment planning.

18F-choline PET-computed tomography for the prediction of early treatment responses to transarterial radioembolization in patients with hepatocellular carcinoma

BACKGROUND

Transarterial radioembolization (TARE) is widely used for the treatment of hepatocellular carcinoma (HCC), but early treatment response can be very difficult to assess. The aim was to evaluate 18F-fluorocholine PET/computed tomography (CT) to assess the treatment response in patients with intermediate or locally advanced HCC.

METHODS

Between March 2019 and July 2020, nine HCC patients treated with TARE, who underwent PET/CT at baseline and 1 month after treatment, were enrolled. The maximum, mean (SUVmean), and peak (SUVpeak) standardized uptake value (SUV), SUV normalized by lean body mass (SUL), and total lesion glycolysis (TLG) were measured. Statistical analysis used the Mann-Whitney test to evaluate the differences in parameters between responders (partial and complete response) and nonresponders (stable or progressive disease) at the 6-month follow-up, according to the modified Response Evaluation Criteria in Solid Tumors.

RESULTS

Three patients were nonresponders (progressive disease and stable disease) and six were responders. Delta SUVmean, delta SUL, and delta TLG could predict an early response (P = 0.02, P = 0.04, and P = 0.02, respectively). None of the pre-therapeutic parameters were correlated with the response. Post-therapeutic SUL, SUVmean, TLG, and SUVpeak were also predictive of the response.

CONCLUSIONS

Our preliminary results showed that changes in certain metabolic parameters (from baseline PET to 1-month PET) are predictive of the response to TARE in HCC (Delta SUVmean, delta TLG, and delta SUL). The absence of post-treatment inflammation could lead to a better prediction than MRI evaluation. This study suggests that 1-month 18F-choline PET/CT could modify the clinical management predicting responders.Video Abstract: http://links.lww.com/NMC/A193.

Prospective Comparison of 18-FDG PET/CT and Whole-Body MRI with Diffusion-Weighted Imaging in the Evaluation of Treatment Response of Multiple Myeloma Patients Eligible for Autologous Stem Cell Transplant

To compare the prognostic values of 18-FDG PET/CT (FDG-PET) and Whole-Body MRI with Diffusion-Weighted Imaging (WB-DW-MRI) in the evaluation of treatment response of Multiple Myeloma (MM) patients eligible for ASCT. Thirty patients with newly diagnosed MM prospectively underwent FDG-PET and WB-DW-MRI at baseline, after induction chemotherapy and after ASCT. Response on WB-DW-MRI was evaluated with the MY-RADS criteria. FDG-PET was considered positive if residual uptake was superior to liver uptake. Imaging results were not used for treatment modification. The impact of imaging results on PFS was analyzed. After a median follow-up of 32 months, 10 patients relapsed. With WB-DW-MRI, post-induction examination was positive in 3/25 and post-ASCT examination was positive in 3/27 patients. However, neither study showed prognostic impact on PFS. FDG-PET was positive in 5/22 post-induction and 3/26 patients post-ASCT, respectively. Positivity of FDG-PET, post-induction or post-ASCT, was associated with a shorter PFS (post-induction: median PFS 19 months vs. not reached, log-rank p = 0.0089; post-ASCT: median PFS 18 months vs. not reached, log-rank p = 0.0005). Preliminary results from this small, single-center, prospective study show that, whether performed post-induction or post-ASCT, FDG-PET has a higher prognostic value than WB-DW-MRI for treatment response evaluation of newly diagnosed MM.

Prospective comparison of 18-FDG PET/CT and whole-body diffusion-weighted MRI in the assessment of multiple myeloma

Magnetic resonance imaging (MRI) and ¹⁸F-fluorodeoxyglucose positron emission tomography-computed tomography (¹⁸FDG 18F-FDG PET-CT) are standard procedures for staging multiple myeloma (MM). Diffusion-weighted sequences applied to whole-body MRI (WB-DWI) improve its sensitivity. We compared the number of MM bone focal lesions (FLs) detected by ¹⁸F-FDG PET-CT and WB-DWI and evaluated the diagnostic performance of ¹⁸F-FDG PET-CT for diffuse infiltration. Thirty newly diagnosed MM patients prospectively underwent 18F-FDG PET-CT and WB-DWI. The criteria for skeletal region positivity were ≥ 1 focal bone lesions (FLs) and/or diffuse disease. MRI with the MY-RADS criteria was used as a reference standard for the diagnosis of diffuse infiltration. ¹⁸F-FDG PET-CT and WB-DWI were both interpreted as positive in 28/30 patients with an agreement of 1.00 (95% CI 0.77-1.00) between the two methods. The mean numbers of FLs were 16.7 detected by ¹⁸F-FDG PET-CT and 23.9 detected by WB-DWI (P = 0.028). WB-DWI detected more FLs in the skull (P = 0.001) and spine (P = 0.006). Agreement assessed using the prevalence and bias-corrected kappa index was moderate (0.40-0.60) for the spine, sternum-ribs and upper limbs and substantial (0.60-0.80) for the pelvis and lower limbs. As regards the diagnosis of diffuse bone marrow infiltration, the sensitivity, specificity and accuracy of ¹⁸F-FDG PET-CT were 0.75, 0.79 and 0.77, respectively. Although WB-DWI detected more FLs than did ¹⁸F-FDG PET-CT, there was no difference in the detection of bone disease on a per-patient basis. ¹⁸F-FDG PET-CT showed high performance, including for evaluation of diffuse infiltration.

Prospective Comparison of 18F-Choline Positron Emission Tomography/Computed Tomography (PET/CT) and 18F-Fluorodeoxyglucose (FDG) PET/CT in the Initial Workup of Multiple Myeloma: Study Protocol of a Prospective Imaging Trial

Background

The International Myeloma Working Group recommends the use of 18-fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) for treatment response evaluation, as it is superior to magnetic resonance imaging (MRI). However, at initial staging, the sensitivity of FDG-PET remains inferior to that of MRI. Therefore, there is a need for an imaging technique that could have a sensitivity equal to that of MRI at diagnosis and could serve to evaluate therapy. 18F-choline has shown increased sensitivity when compared with 18-FDG, with about 75% more lesions detected in patients with relapsed or progressive multiple myeloma (MM).

Objective

Our primary objective is to prospectively compare the detection rate of bone lesions by 18F-choline PET/CT (FCH-PET) and FDG-PET in newly diagnosed MM. Our secondary objectives are to assess the accuracy of both PET modalities for the detection of bone lesions and the diagnosis of diffuse disease, to assess the detection rate of extramedullary lesions.

Methods

We will prospectively include 30 patients in a paired comparative accuracy study. Patients with de novo MM will undergo FCH-PET, FDG-PET, and whole-body MRI (WB-MRI) within a 3-week period. WB-MRI will be composed of conventional sequences on the spine and pelvis and of whole-body diffusion axial sequences. The following 6 skeletal areas will be defined: skull, sternum/costal grid, spine, pelvis, superior limbs, and inferior limbs. The number of focal lesions, their respective localization, and intensity of uptake will be retrieved for each skeletal area. Readings will be performed blinded from other imaging techniques. The reference standard will be WB-MRI. Focal lesions present on PET/CT but not on WB-MRI will require a decision made with a consensus of experts based on clinical and imaging data. The number of bone lesions and number of extramedullary lesions will be compared using the Wilcoxon test. The accuracy of FCH-PET and FDG-PET will be compared using the McNemar test.

Results

The study started in September 2019, and enrollment is ongoing. As of June 2020, 8 participants have been included. Data collection is expected to be completed in June 2021, and the results are expected to be available in December 2021.

Conclusions

This study will assess if FCH-PET is superior to FDG-PET for the evaluation of MM tumor burden. This will pave the way for future prospective evaluations of the prognostic value of 18-FCH for treatment response evaluation in MM patients. Additionally, this work may provide new perspectives for better assessment of the risk of smoldering MM progressing to MM.

Trial Registration

ClinicalTrials.gov NCT03891914; https://clinicaltrials.gov/ct2/show/NCT03891914

International Registered Report Identifier (IRRID)

DERR1-10.2196/17850

Multicenter Pilot Study to Assess a Biphasic Calcium Phosphate Implant for Functional and Aesthetic Septorhinoplasty

Importance: A validated biomaterial would have several medical advantages in septorhinoplasties requiring a large-volume graft such as avoiding donor site morbidity, making ambulatory surgery possible, and reducing surgical costs. Objective: To assess the safety and efficacy of a ceramic to treat saddle and crooked noses. The main endpoint was the biocompatibility of the implant. The secondary endpoint was its functional and aesthetic efficacy. Design, Setting, and Participants: The nasal septum (NASEPT) study is a pilot multicenter noncomparative prospective phase IIa clinical trial. The biomaterial tested was a biphasic calcium phosphate implant composed of 75% hydroxyapatite and 25% beta tri calcium phosphate. This versatile material can be used to replace septal skeleton when it is absent or nonusable. We included 25 patients with a multifractured osseous and cartilaginous framework after several traumas or surgeries. The implant placement technique was identical to an extracorporeal septoplasty through the external approach. Main Outcomes and Measures: The primary endpoint was the occurrence of expected adverse and severe adverse events. The secondary endpoints were clinical functional and aesthetic results and histological microscopic modifications. Results: Any extrusion, infection, pain, and epistaxis were observed. All implants were placed in a sagittal, straight, and solid position without extralobular depression. Comparisons between pre- and postoperative symptoms showed that nasal comfort (p < 10^-4) and quality of life (p < 10^-4) were dramatically improved in all patients. The nasolabial angle (p = 0.047) and the columellar projection (p = 0.024) were improved after surgery. Histological data showed little submucosal inflammation at 6 months with well-differentiated epithelium. The mean follow-up was 23 months: three patients underwent revision surgery for functional or aesthetic details and four implants were removed (16%) owing to a foreign body reaction between 17 and 74 months. Conclusion and Relevance: The NASEPT implant meets functional and aesthetic requirements in complex septorhinoplasties but its long-term biocompatibility needs to be improved. It could potentially avoid donor site morbidity.

Choline PET/CT in Multiple Myeloma

The field of multiple myeloma (MM) imaging has evolved. The International Myeloma Working Group recently recommended performing 18F-fluorodeoxyglucose glucose (18FDG) positron emission tomography/computed tomography (PET/CT) with the aim of staging MM patients at baseline and evaluating response to therapy. Novel oncological radiotracers such as 11C-Choline and 18F-Fluorocholine, have been studied in comparison with 18FDG, mostly in MM patients presenting with refractory disease or suspected relapse. Choline-based tracers may overcome some limitations of 18FDG, which include a lack of sensitivity in depicting skull lesions and the fact that 10% of MM patients are FDG-negative. The majority of MM lesions display a higher uptake of Choline than FDG. Also, in many situations, Choline may offer better lesion visualization, with a higher tumor to background ratio; however, various patterns of Choline and FDG uptake have been observed in MM and some limitations, notably as regards liver lesions, should be recognized. Overall, Choline may provide additional detection of up to 75% more lesions. This article aims to provide a comprehensive review of the potential role of Choline in multiple myeloma, as compared to FDG, encompassing Choline physiopathology as well as data from clinical studies.

Computational fluid dynamics simulation to compare large volume irrigation and continuous spraying during nasal irrigation

BACKGROUND

Nasal irrigation is now widely recognized as a treatment for chronic rhinosinusitis and during the postoperative period. However, there are no guidelines for performing irrigation. This study used computational fluid dynamics (CFD) simulation objective physical parameters to optimize and increase the efficiency of nasal irrigation and to compare large-volume, manual, and gravity pressure irrigation vs small-volume continuous spraying.

METHODS

A 3-dimensional (3D) sinonasal model was constructed from a healthy adult high-resolution computed tomography (CT) scan. The 3D nasal model was constructed using a tetrahedral and hex-dominant mesh grid with TGRID™ 16 (ANSYS Inc., Villeurbanne, France) software. A structured hex mesh was created inside the domain using the Hexcore meshing method. The final mesh had a total of 9.6 × 10⁶ cells with an average size of 0.29 mm³ , or an average volume of 2.42 × 10^-2 mm³ . Navier-Stokes equations were resolved with the standard k - ε  model.

RESULTS

Large-volume irrigation (15 mL/s) covered all zones (136 to 310 cm² ) rapidly with strong shear stress and prolonged contact time (310 mPa 3.26 seconds for gravity mode and 280 mPa 3.35 seconds for manual pressure mode). Continuous spraying (3 mL/second) covered all areas (76 to 310 cm² ) but with far less volume, more slowly, with low shear stress (50 mPa), and with shorter contact time (1.84 seconds). The surface wetted by time in contact was 135.4, 113.9, and 46.6 cm² for gravity, manual pressure mode, and continuous spraying, respectively.

CONCLUSION

CFD simulation visualizes the circulation of water during nasal irrigation and makes it possible to determine objective parameters to decide which mode of irrigation may be used.

Prognostic utility of pre-transplantation [18 F] fluorodeoxyglucose positron emission tomography/computed tomography in patients with diffuse large B-cell lymphoma who underwent rituximab, dexamethasone, high-dose cytarabine, carboplatin salvage chemotherapy

We analysed the outcomes of 62 patients with refractory/relapsed diffuse large B-cell lymphoma (rrDLBCL) who had pre-transplantation fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) after R-DHAC (rituximab, dexamethasone, high-dose cytarabine, carboplatin) salvage chemotherapy, and were evaluated using Deauville criteria and total lesion glycolysis (TLG). A positive pre-transplantation PET/CT with Deauville score of 5 was associated with shorter progression-free survival (PFS) (P = 0·01), while a Deauville score of 4 was not predictive of outcome. Only pre-transplant TLG was significantly associated with both PFS (P = 0·005) and overall survival (P = 0·03). TLG deserves to be further investigated in prospective studies.

Retrospective Study Comparing WBC scan and 18F-FDG PET/CT in Patients with Suspected Prosthetic Vascular Graft Infection

OBJECTIVES

Prosthetic vascular graft infections (PVGIs) are associated with high mortality rates. To improve treatment outcome, an early and definite diagnosis is critical, and current diagnostic criteria are often insufficient. The accuracy of 2-deoxy-2-[fluorine-18]-fluoro-d-glucose positron emission tomography integrated with computed tomography (¹⁸F-FDG PET/CT) and white blood cell (WBC) scan for the diagnosis of PVGI were compared.

METHODS

A retrospective single centre study was conducted on patients undergoing WBC scan and ¹⁸F-FDG PET/CT for a suspected PVGI between April 2013 and June 2016 at the Bordeaux University Hospital, France. The diagnostic value of both imaging tests was assessed for all grafts, using receiver operating characteristic (ROC) curve analysis. Images were independently interpreted by two nuclear medicine physicians blinded to the patients' clinical and other imaging data.

RESULTS

Thirty-nine patients were included, of whom 15 had PVGI. Antibiotic treatment was started before nuclear imaging for 16 patients, including nine patients with a PVGI. The 96 grafts of these patients were analysed, and 19 were infected. The diagnostic value of the WBC scan was significantly higher than ¹⁸F-FDG PET/CT (ROC AUC = 0.902, 95% CI 0.824-0.980, and 0.759, CI 95% (0.659-0.858), respectively, p = .0071). Interobserver agreement was good for ¹⁸F-FDG PET/CT and excellent for WBC scan (kappa value of 0.76, 95% CI 0.62-0.9, and 0.97, 95% CI 0.92-1, respectively). Only one patient had a false negative ¹⁸F-FDG PET/CT result under antibiotic therapy.

CONCLUSION

The WBC scan has a better diagnostic value than ¹⁸F-FDG PET/CT for PVGI diagnosis.

Self-crosslinked fibrous collagen/chitosan blends: Processing, properties evaluation and monitoring of degradation by bi-fluorescence imaging

Porous collagen/chitosan scaffolds with different Collagen:Chitosan (Coll:Ch) ratios were prepared by freeze-drying followed by self-crosslinking via dehydrothermal treatment (DHT) and characterized as biomaterials for tissue engineering. Cy7 and Cy5.5 fluorochromes were covalently grafted to collagen and chitosan, respectively. Thus, it was possible, using optical fluorescence imaging of the two fluorochromes, to simultaneously track their in vivo biodegradation, in a blend scaffold form. The fluorescence signal evolution, due to the bioresorption, corroborated with histological analysis. In vitro cytocompatibility of Coll:Ch blend scaffolds were evaluated with standardized tests. In addition, the scaffolds showed a highly interconnected porous structure. Extent of crosslinking was analyzed by convergent analysis using thermogravimetry, Fourier Transform Infrared Spectroscopy and PBS uptake. The variations observed with these techniques indicate strong interactions between collagen and chitosan (covalent and hydrogen bonds) promoted by the DHT. The mechanical properties were characterized to elucidate the impact of the different processing steps in the sample preparation (DHT, neutralization and sterilization by β-irradiation) and showed a robust processing scheme with low impact of Coll:Ch composition ratio.

Cell and tissue responses at the interface with a chitosan hydrogel intended for vascular applications: in vitro and in vivo exploration

AIMS

The need for small caliber vessels to treat cardiovascular diseases has grown. However, synthetic polymers perform poorly in small-diameter applications. Chitosan hydrogels can provide a novel biological scaffold for vascular engineering. The goal of this study was to explore host cell and tissue behavior at the interface with chitosan-based scaffolds in vitro and in vivo.

METHODS AND RESULTS

in vitro, we assessed the ability of endothelial cells lining chitosan hydrogels to produce tissue factor (TF), thrombomodulin (TM) and nitric oxide. We showed that endothelial cells behave as a native endothelium since under stimulation, TF and TM expression increased and decreased, respectively. Endothelial cells seeded on chitosan produced nitric oxide, but no change was observed under stimulation. After in vivo subcutaneous implantation of chitosan hydrogels in rats, macrophage activation phenotypes, playing a crucial role in biomaterial/tissue, were explored by immunohistochemistry. Our results suggested a balance between pro- and anti-inflammatory signals since we observed an inflammatory response in favor of macrophage M2 phenotype.

CONCLUSION

in vitro exploration of endothelial cell response at the interface with chitosan hydrogel showed a functional endothelium and in vivo exploration of tissue response revealed a biointegration of chitosan hydrogels.

Prospective, randomized, controlled, open-label study to compare efficacy of a mineral-rich solution vs normal saline after complete ethmoidectomy

Purposes

The purpose of this study was to compare the efficacy of a mineral-rich solution vs normal saline solution (0.9% NaCl) following endoscopic complete bilateral ethmoidectomy.

Methods

This was a prospective, multicenter, randomized, controlled, open-label trial in subjects suffering from steroid-resistant sinonasal polyposis. Adults performed 4 nasal irrigations of mineral or saline solutions daily for 28 days. Evaluations included subject-reported RHINO quality of life (QoL) and NOSE scores, tolerability, and satisfaction, the Lund–Kennedy endoscopic score and assessments of crusting, secretions and mucociliary clearance (rhinoscintigraphy).

Results

A total of 189 subjects were randomized. Clinically relevant improvements (> 20 points) in RhinoQOL and NOSE scores were measured in both groups without any significant inter-group difference. Among the subjects with impaired RhinoQOL at pre-inclusion, the change in Impact-RhinoQOL score was significantly superior in mineral-rich vs saline solution at day 21 (p = 0.028) and day 28 (p = 0.027). The Lund–Kennedy score continuously improved in both groups earlier with the mineral-rich solution. Crusts were significantly fewer in number and less severe/obstructive in patients receiving mineral-rich vs saline solution at day 7 (p = 0.026) and day 14 (p = 0.016). Furthermore, secretions disappeared significantly more quickly and were less thick/purulent with mineral-rich solution at day 14 (p = 0.002) and day 21 (p = 0.043). Less epistaxis was reported in the mineral vs saline solution (p = 0.008 at day 21).

Conclusions

Our findings indicate that the composition of a nasal irrigation solution influences endoscopic scores and QoL after sinus surgery for patients over 60, those with an initially poor QoL and higher symptom score, and smokers.

In vitro Evidence of Improved Antimicrobial Efficacy of Silver and Triclosan Containing Vascular Grafts Compared with Rifampicin Soaked Grafts

OBJECTIVES

The aim was to compare the antimicrobial efficacy of four different grafts: a standard graft (Intergard, IG), an IG graft soaked in rifampicin (IGrif), a silver impregnated graft (Intergard Silver, IGS), and a silver + triclosan impregnated graft (Intergard Synergy, IGSy).

METHODS

This was a seven day in vitro study. The IG, IGrif, IGS, and IGSy grafts were each contaminated separately with the following microorganisms: Staphylococcus epidermidis, Methicillin resistant Staphylococcus aureus (MRSA), Escherichia coli, and Candida albicans from both clinical and American Type Culture Collection (ATCC) origins. The in vitro antimicrobial efficacy was evaluated by time to kill assays at T0, T24h, T48h, T72h, and T168h. Bactericidal activity was defined as >3 log₁₀ reduction factor (logRF). Additionally, Rifampicin, triclosan and silver resistance development were screened.

RESULTS

As anticipated for the non-antimicrobial IG, all microorganism strains proliferated. The IGSy and the IGS showed a seven day bactericidal efficacy (>3 logRF) for all tested microorganisms. This efficacy was confirmed at all time points for IGSy only, demonstrating faster bactericidal efficacy than IGS. The IGrif demonstrated a seven day bactericidal efficacy against the ATCC MRSA only, while showing no activity against C. albicans and ATCC E. coli. Regarding ATCC S. epidermidis, clinical MRSA and clinical E. coli, IGrif, although bactericidal at earlier time points, lost its antimicrobial efficacy at seven days leading to the emergence of rifampicin resistant mutants in four of six, two of six, and two of six assays, respectively. Mutant strains were also detected in ATCC MRSA in one of six assays. No triclosan or silver resistance has emerged at T7days.

CONCLUSION

For all microorganisms tested, the Synergy graft combining silver with triclosan demonstrated a more sustainable and efficient seven day antimicrobial activity than the rifampicin soaked graft. The emergence of rifampicin resistant mutants suggests preference for a Synergy graft over a graft soaked in rifampicin, to prevent or treat an infection when a biological solution is not feasible.

Assessment of vertebral microarchitecture in overt and mild Cushing's syndrome using trabecular bone score

OBJECTIVE

Osteoporotic fractures associated with Cushing's syndrome (CS) may occur despite normal bone mineral density (BMD). Few studies have described alterations in vertebral microarchitecture in glucocorticoid-treated patients and during CS. Trabecular bone score (TBS) estimates trabecular microarchitecture from dual-energy X-ray absorptiometry acquisitions. Our aim was to compare vertebral BMD and TBS in patients with overt CS and mild autonomous cortisol secretion (MACE), and following cure of overt CS.

SETTING

University Hospital.

DESIGN

Monocentric retrospective cross-sectional and longitudinal studies of consecutive patients.

PATIENTS

A total of 110 patients were studied: 53 patients had CS (35, 11 and 7 patients with Cushing's disease, bilateral macronodular adrenal hyperplasia and ectopic ACTH secretion respectively); 39 patients had MACE (10 patients with a late post-operative recurrence of Cushing's disease and 29 patients with adrenal incidentalomas); 18 patients with non-secreting adrenal incidentalomas. 14 patients with overt CS were followed for up to 2 years after cure.

RESULTS

Vertebral osteoporosis at BMD and degraded microarchitecture at TBS were found in 24% and 43% of patients with CS, respectively (P < .03). As compared to patients with nonsecreting incidentalomas, patients with MACE had significantly decreased TBS (P < .04) but not BMD. Overt fragility fractures tended to be associated with low TBS (P = .07) but not with low BMD. TBS, but not BMD values, decreased with the intensity of hypercortisolism independently of its aetiology (P < .01). Following remission of CS, TBS improved more markedly and rapidly than BMD (10% vs 3%, respectively; P < .02).

CONCLUSION

Trabecular bone score may be a promising, noninvasive, widely available and inexpensive complementary tool for the routine assessment of the impact of CS and MACE on bone in clinical practice.

Decellularized and matured esophageal scaffold for circumferential esophagus replacement: Proof of concept in a pig model

Surgical resection of the esophagus requires sacrificing a long portion of it. Its replacement by the demanding gastric pull-up or colonic interposition techniques may be avoided by using short biologic scaffolds composed of decellularized matrix (DM). The aim of this study was to prepare, characterize, and assess the in vivo remodeling of DM and its clinical impact in a preclinical model. A dynamic chemical and enzymatic decellularization protocol of porcine esophagus was set up and optimized. The resulting DM was mechanically and biologically characterized by DNA quantification, histology, and histomorphometry techniques. Then, in vitro and in vivo tests were performed, such as DM recellularization with human or porcine adipose-derived stem cells, or porcine stromal vascular fraction, and maturation in rat omentum. Finally, the DM, matured or not, was implanted as a 5-cm-long esophagus substitute in an esophagectomized pig model. The developed protocol for esophageal DM fulfilled previously established criteria of decellularization and resulted in a scaffold that maintained important biologic components and an ultrastructure consistent with a basement membrane complex. In vivo implantation was compatible with life without major clinical complications. The DM's scaffold in vitro characteristics and in vivo implantation showed a pattern of constructive remodeling mimicking major native esophageal characteristics.

Numerical simulation of two consecutive nasal respiratory cycles: toward a better understanding of nasal physiology

BACKGROUND

Computational fluid dynamic (CFD) simulations have greatly improved the understanding of nasal physiology. We postulate that simulating the entire and repeated respiratory nasal cycles, within the whole sinonasal cavities, is mandatory to gather more accurate observations and better understand airflow patterns.

METHODS

A 3-dimensional (3D) sinonasal model was constructed from a healthy adult computed tomography (CT) scan which discretized in 6.6 million cells (mean volume, 0.008 mm³ ). CFD simulations were performed with ANSYS©FluentTMv16.0.0 software with transient and turbulent airflow (k-ω model). Two respiratory cycles (8 seconds) were simulated to assess pressure, velocity, wall shear stress, and particle residence time.

RESULTS

The pressure gradients within the sinus cavities varied according to their place of connection to the main passage. Alternations in pressure gradients induced a slight pumping phenomenon close to the ostia but no movement of air was observed within the sinus cavities. Strong movements were observed within the inferior meatus during expiration contrary to the inspiration, as in the olfactory cleft at the same time. Particle residence time was longer during expiration than inspiration due to nasal valve resistance, as if the expiratory phase was preparing the next inspiratory phase. Throughout expiration, some particles remained in contact with the lower turbinates. The posterior part of the olfactory cleft was gradually filled with particles that did not leave the nose at the next respiratory cycle. This pattern increased as the respiratory cycle was repeated.

CONCLUSION

CFD is more efficient and reliable when the entire respiratory cycle is simulated and repeated to avoid losing information.

In Vitro Mechanical Property Evaluation of Chitosan-Based Hydrogels Intended for Vascular Graft Development

Vascular grafts made of synthetic polymers perform poorly in cardiac and peripheral bypass applications. In these applications, chitosan-based materials can be produced and shaped to provide a novel scaffold for vascular tissue engineering. The goal of this study was to evaluate in vitro the mechanical properties of a novel chitosan formulation to assess its potential for this scaffold. Two chitosan-based hydrogel tubes were produced by modulating chitosan concentration. Based on the standard ISO 7198:1998, the hydrogel tubes were characterized in vitro in terms of suture retention strength, tensile strength, compliance, and burst pressure. By increasing chitosan concentration, suture retention value increased to reach 1.1 N; average burst strength and elastic moduli also increased significantly. The compliance seemed to exhibit a low value for chitosan tubes of high concentration. By modulating chitosan concentration, we produced scaffolds with suitable mechanical properties to be implanted in vivo and withstand physiological blood pressures.

A useful and easy to develop combined stress test for myocardial perfusion imaging: Regadenoson and isometric exercise, preliminary results

BACKGROUND

Regadenoson, a selective A2a receptor agonist, is a vasodilator increasingly used in myocardial perfusion imaging. Adjunction of isometric exercise is a simple method that could improve side effect profile while providing better image quality.

METHODS

Patients undergoing SPECT MPI were prospectively enrolled in handgrip-Regadenoson (HG-Reg test, N = 20) and Regadenoson (Reg) stress test (N = 40). Investigator blinded to stress test analyzed clinical data and images.

RESULTS

Heart rate (HR) increase was statistically higher in the HG-Reg group (27 vs 22 bpm, P = .019). Decrease in SBP was less frequent in the HG-Reg group than in the Reg group (55% vs 85.5%, P = .005), there were less drops >10 mmHg (45% vs 77.7%, P = .012). During stress testing, fewer subjects reported at least one side effect in the HG-Reg compared to Reg group (70% vs 92.5%, P = .021). Images were more often classified as good in the HG-Reg group (75% vs 52.5% in the Reg group, P = .25).

CONCLUSIONS

Adjunction of handgrip exercise to Regadenoson administration is a well-tolerated and easy method, without loss of time. Furthermore, image quality seems to be better.

[Tissue engineering: a multidisciplinary approach]

The prostheses have been around for thousands of years. Initially, it was substitute materials to replace members (leg, foot, hand) or for surgery (suture). The materials used have evolved, but they had never been created for medical applications. Recently, other strategies have emerged to construct or repair tissues. They are based on the use of biological components such as proteins or cells and provide a biological dimension to the term "biomaterial" and they often involve engineering. We illustrate the tissue engineering approaches using the examples of muscle and vessel regeneration strategies in the frame of restorative medicine.

Early prosthetic aortic valve infection identified with the use of positron emission tomography in a patient with lead endocarditis

BACKGROUND

18-Fluorodeoxyglucose positron emission tomography/computerized tomography (FDG PET/CT) scanning has recently been proposed as a diagnostic tool for lead endocarditis (LE).

OBJECTIVE

FDG PET/CT might be also useful to localize associated septic emboli in patients with LE.

CASE PRESENTATION

We report an interesting case of a LE patient with a prosthetic aortic valve in whom a trans-esophageal echocardiogram did not show associated aortic endocarditis. FDG PET/CT revealed prosthetic aortic valve infection. A second TEE performed 2 weeks after identified aortic vegetation. A longer duration of antimicrobial therapy with serial follow-up echocardiography was initiated. There was also increased uptake in the sigmoid colon, corresponding to focal polyps resected during a colonoscopy.

CONCLUSION

FDG PET/CT scanning seems to be highly sensitive for prosthetic aortic valve endocarditis diagnosis. This promising diagnostic tool may be beneficial in LE patients, by identifying septic emboli and potential sites of pathogen entry.

Hodgkin lymphoma: a negative interim-PET cannot circumvent the need for end-of-treatment-PET evaluation

We examined the outcome of a cohort of patients with Hodgkin lymphoma (HL) in order to assess if fluorodeoxyglucose (FDG) positron emission tomography-computed tomography (PET/CT) at the end of treatment (end-PET) can be omitted when the interim PET (int-PET) is negative. Seventy-six ABVD(adriamycin, bleomycin, vinblastine, dacarbazine)-treated patients were retrospectively included. No change in treatment was made on the basis of int-PET results. Suspicious foci on end-PET received biopsy confirmation whenever possible. Median follow-up was 58·9 months. Uptake on int-PET higher than liver (scores 4-5) was rated positive according to the Lugano classification, while a positive end-PET corresponded to scores 3, 4 and 5. Fifteen patients had treatment failure. Sensitivity, specificity, positive predictive value (PPV), negative predictive value and accuracy of int-PET were 46·7%, 85·2%, 43·8%, 86·7% and 77·6%, respectively. For end-PET the figures were: 80%, 93·4%, 75%, 95% and 90·8%. Eight patients with negative int-PET had treatment failure; six of them were identified as non-responders with end-PET. The 5-year progression-free survival (PFS) was 87% for patients with negative int-PET versus 56% with positive int-PET. The 5-year PFS was 96% with negative end-PET versus 23% with positive end-PET. The prognostic information from int-PET as regards PFS (log-rank test P = 0·0048) was lower than that provided by end-PET (P < 0·0001). Int-PET predicted only half of the failures. When used in clinical routine, a negative int-PET study cannot obviate the need for end-PET examination.

Effect of dosimeter's position on occupational radiation extremity dose measurement for nuclear medicine workers during (18)F-FDG preparation for PET/CT

Background

The recent spread of positron emission tomography-computed tomography (PET/CT) poses extremity dosimetry challenges. The question arose whether the radiation dose measured by the ring thermoluminescent dosimeter usually worn on the proximal phalanx (P1) of the index finger measures doses that are representative of the true doses received by the upper extremities of the operators. A prospective individual dosimetry study was performed in which the personal equivalent dose Hp (0.07) received during a specific 2-[¹⁸F]fluoro-2-deoxy-d-glucose (¹⁸F-FDG) manual dose-dispensing procedure was measured in a paired design by two operational personal electronic dosimeters fitted on the palm side of the index finger, namely in the P1 and distal phalanx (P3) positions. The study participants were ten nuclear medicine technologists working in two nuclear medicine departments. The personal equivalent radiation doses received by the palm side of the proximal phalanx of the index finger [Hp (0.07)_P1] and that received by the distal phalanx [Hp (0.07)_P3] were compared.

Results

The median Hp (0.07)_P3/Hp (0.07)_P1 ratio per participant varied between 1.0 and 2.5 (based on 23 to 31 measurements per participant). The 271 paired measurements revealed a crude Hp (0.07)_P3/Hp (0.07)_P1 ratio of 1.67, significantly different from 1 (p = 0.0004, 95 % CI [1.35–2.07]). When adjusted on participant’s gender and mother vial activity, the ratio was similar (1.53, p = 0.003, 95 % CI [1.22–1.92]).

Conclusions

The study demonstrated a significant disparity that may exist between the radiation doses measured in the P1 and P3 positions of operators during ¹⁸F-FDG manipulation. These findings emphasize the importance of performing workplace dosimetry studies adapted to each radiopharmaceutical and manipulation thereof, aiming to guarantee optimal workers’ dosimetry monitoring schemes.

Trial registration

Hospital Nursing and Paramedical Research Program (PHRIP, 2011–2013) from the French Ministry of Health (DGOS), http://social-sante.gouv.fr/IMG/pdf/Resultats_PHRIP_2011.pdf

Accuracy of Positron Emission Tomography as a Diagnostic Tool for Lead Endocarditis: Design of the Prospective Multicentre ENDOTEP Study

Background: Rates of pacemaker implantation are steadily increasing and as patients are living longer, endovenous leads remain implanted for an extended period of time thereby increasing the risk of cardiac implantable electronic device (CIED) infection. Investigating fever of unknown origin in patients with implanted pacemakers can be challenging. Recently, ¹⁸F-fluorodeoxyglucose positron emission tomography/computerised tomography (¹⁸F-FDG-PET/CT) scanning has been used as a diagnostic tool for lead endocarditis in small studies. Objectives: ENDOTEP is a prospective and multicentre study designed to evaluate the accuracy of ¹⁸F-FDG-PET/CT scanning in the diagnosis of lead endocarditis. Methods: A total of 250 patients referred for pacemaker extraction due to suspicion of an infected device will be prospectively enrolled in six French regional centres for investigation and treatment of CIED infection. ¹⁸F-FDG-PET/CT scanning (index test) will be performed in each patient in the 48 hours preceding lead extraction. Bacteriological cultures (reference standard) will assess the presence of lead endocarditis, blind to ¹⁸F-FDG-PET/CT results. Enrolment started in June 2015 and is expected to end by June 2017. The primary objective will be to establish the sensitivity of the ¹⁸F-FDG-PET/CT scan for lead endocarditis. Secondary objectives will include other accuracy parameters, inter-observer agreement in the interpretation of ¹⁸F-FDG-PET/CT scanning, the influence of previous antibiotic therapy on ¹⁸F-FDG-PET/CT diagnostic accuracy and assessment of septic emboli associated to lead endocarditis. Conclusion: The ENDOTEP study will examine the ability of ¹⁸F-FDG-PET/CT scanning to avoid possible false-positive results, as is common using the current usual diagnostic strategy and may lead to unnecessary extraction of implants in patients with suspected lead infection.

Comparison of the Antimicrobial Properties of Silver Impregnated Vascular Grafts with and without Triclosan

OBJECTIVES

The aim was to compare the antimicrobial efficacy of the silver impregnated collagen coated polyester vascular graft (IGS) with an identical graft combining silver and triclosan (IGSy).

METHODS

This was an in vitro study. A non-antimicrobial collagen polyester vascular graft served as control (IG). The IG, IGS, and IGSy grafts were contaminated separately with inoculates of each of the following micro-organisms: Staphylococcus epidermidis (SE), methicillin resistant Staphylococcus aureus (MRSA), and Escherichia coli producing extended spectrum beta-lactamase (ESBL-EC) or Candida albicans (CA). MRSA, ESBL-EC, and CA were obtained from retrieved infected grafts. The in vitro antimicrobial efficacies of the contaminated grafts were evaluated by time to kill assays over a 24 hour period in accordance with CLSI Guideline M26-A. All assays were repeated six times. Bacterial survival numbers were obtained at 1, 4, 8, and 24 hours using a standard plate count procedure. Bactericidal activity was defined as a 3 log10 reduction factor (logRF). To calculate the overall difference in the mean log10 CFU/mL within 24 hours, a one way ANOVA with a Bonferroni correction was calculated separately for each graft.

RESULTS

The IG graft showed an increase in the number of viable organisms for the four strains tested. IGSy offered better antimicrobial properties than IGS for both ESBL-EC and MRSA, since only the IGSy graft achieved > 3 logRF and fulfilled the standard criteria for bactericidal activity at 24 hours with 3.78 and 4.08 logRF, respectively. For samples inoculated with SE and CA, both antimicrobial grafts achieved 24 hour bactericidal activity with > 3 logRF. However, for CA the one-way ANOVA analysis demonstrated that the IGSy graft performed differently in terms of speed of antimicrobial action, appearing more active as early as 4 hours following inoculation (p = .007).

CONCLUSION

In the in vitro conditions, the Synergy vascular graft combining silver with triclosan demonstrated better short-term antimicrobial activity than the silver graft for all micro-organisms tested.

Colorectal tissue engineering: A comparative study between porcine small intestinal submucosa (SIS) and chitosan hydrogel patches

OBJECTIVE

Tissue engineering may provide new operative tools for colorectal surgery in elective indications. The aim of this study was to define a suitable bioscaffold for colorectal tissue engineering.

METHODS

We compared 2 bioscaffolds with in vitro and in vivo experiments: porcine small intestinal submucosa (SIS) versus chitosan hydrogel matrix. We assessed nontoxicity of the scaffold in vitro by using human adipose-derived stem cells (hADSC). In vivo, a 1 × 2-cm colonic wall defect was created in 16 rabbits. Animals were divided randomly into 2 groups according to the graft used, SIS or chitosan hydrogel. Graft area was explanted at 4 and 8 weeks. The end points of in vivo experiments were technical feasibility, behavior of the scaffold, in situ putative inflammatory effect, and the quality of tissue regeneration, in particular smooth muscle layer regeneration.

RESULTS

In vitro, hADSC attachment and proliferation occurred on both scaffolds without a substantial difference. After proliferation, hADSCs kept their mesenchymal stem cell characteristics. In vivo, one animal died in each group. Eight weeks after implantation, the chitosan scaffold allowed better wound healing compared with the SIS scaffold, with more effective control of inflammatory activity and an integral regeneration of the colonic wall including the smooth muscle cell layer.

CONCLUSION

The outcomes of in vitro experiments did not differ greatly between the 2 groups. Macroscopic and histologic findings, however, revealed better wound healing of the colonic wall in the chitosan group suggesting that the chitosan hydrogel could serve as a better scaffold for colorectal tissue engineering.

High performances of (18)F-fluorodeoxyglucose PET-CT in cardiac implantable device infections: A study of 40 patients

BACKGROUND

Cardiovascular implantable electronic devices (CIED) infections are life-threatening complications. The diagnosis can be difficult to establish. Our purpose is to evaluate the diagnostic value of (18)F-FDG PET.

METHODS

Forty patients who received work-up for suspected CIED infection were retrospectively included (group 1) and compared with 40 controls (group 2); CIED patients were referred for oncologic PET. PET-CT data were blindly assessed. Interpretation was based on visual analysis of both attenuation-corrected and non-corrected images and a semi-quantitative analysis was performed. The gold standard was bacteriological data of explanted devices or clinical follow-up for at least 1 year.

RESULTS

Infection was present in 18 out of 40 patients of group 1. Sensitivity, specificity, positive predictive value, and negative predictive value of PET-CT were 83%, 95%, 94%, and 88%, respectively. Accuracy was 90%. PET-CT revealed the presence of additional pathological hypermetabolic foci in 28% of cases. PET-CT was negative at implanted devices in all patients of group 2.

CONCLUSION

(18)F-FDG PET-CT is helpful in the work-up of suspected CIED infections. It is a potential tool to make the accurate diagnosis of CIED infection and to assess the extent of infection. The promising results in this indication need to be validated in a prospective multicenter study.

18F-FDG PET-CT in suspected prosthetic vascular graft infection

BACKGROUND

Diagnosis of prosthetic vascular graft infections is a clinical challenge, and surgical therapy is associated with comorbidity. Therefore, accurate diagnostic methods are required for their optimal management.

METHODS

A 61-year-old-patient presented with erysipelas of the right lower limb 7 months after receiving a hybrid femoropopliteal bypass composed of a saphenous vein distally and external supported polytetrafluoroethylene proximally. He had been first treated for suspicious of septic arterial thrombosis or false aneurysm with antibiotics. A computed tomography (CT) angiogram was performed to detect any potential infection of the bypass and to explore erysipelas. It revealed a subcutaneous infiltration and an infiltration of the right groin but no anastomotic pseudoaneurysm or thrombosis of the bypass. The 2-[18F]-fluoro-2-desoxy-d-glucose positron emission tomography (18F-FDG PET) evidenced a significant uptake of cutaneous and subcutaneous tissue but no uptake on the vascular prosthetic graft. Therefore, the bypass was considered as noninfected and antibiotics were continued for 3 months. A physical examination on antibiotic cessation revealed a nonerythematous thigh with a C-reactive protein level significantly decreased to 36 mg/L and a normal white blood cell count. A PET scan confirmed this clinical improvement as attested by a dramatically decreased uptake of cutaneous and subcutaneous tissues and still no uptake of the graft.

CONCLUSIONS

In conclusion, this case highlights the role that 18F-FDG PET-CT may play in excluding suspected prosthetic graft infection, thanks to its high sensitivity and in avoiding needless revision surgery with subsequent comorbidities.

[Recurrent syncope in head and neck cancer: a case report]

The repeated syncopes in case of head and neck cancer are a complication rarely described in the literature. They occur when the tumor invade the carotid sinus or the afferent fibers of the glossopharyngeal nerve. We report the case of a 62-year-old man presented episodes of syncope synchronous of a recurrent hypopharyngeal tumor scheduled for chemotherapy and gastrostomy. A computerized tomography showed a voluminous tumor expanded to the carotid and parapharyngeal spaces. After treatment by isporenaline chlorhydrate in intensive care unit, a pacemaker was implanted to prevent syncopes and allowed the beginning of the chemotherapy.