In Vivo Measurement of Human Achilles Tendon Morphology Using Freehand 3-D Ultrasound

This study investigated the accuracy of phantom volume and length measurements and the reliability of in vivo Achilles tendon (AT) volume, length and cross-sectional area measurements obtained using freehand 3-D ultrasound. Participants (n = 13) were scanned on consecutive days under active and passive loading conditions. In vivo AT length was evaluated using a two-point method and an approach that accounted for AT curvature (centroid method). Three-dimensional ultrasound provided accurate measures of phantom volume and length (mean difference = 0.05 mL and 0.2 mm, respectively) and reliable in vivo measures of AT volume, length and average cross-sectional area, with all intra-class correlations coefficients greater than 0.98. The mean minimally detectable changes for in vivo AT volume, two-point length and centroid length were 0.2 mL, 1.5 mm and 2.0 mm, respectively. Two-point AT length underestimated centroid AT length by 0.7 mm, suggesting that the effect of curvature on in vivo AT length is negligible.     

A validated assay for the quantitative analysis of tranexamic acid in human serum by liquid chromatography coupled with electrospray ionization mass spectrometry

BackgroundTranexamic acid is a synthetic lysine analog used for management of bleeding disorders. The objective of this study was first to develop a method for measurement of tranexamic acid in human serum using liquid chromatography coupled to ion-trap mass spectrometry (LC-MS/MS), and then to validate it throughout a wide range of concentrations allowing quantification in patients receiving tranexamic acid infusion during surgery.MethodsSerum samples (100 µL) were subjected to protein precipitation with perchloric acid, and after pH adjustment, tranexamic acid and internal standard were separated on a C₁₈ column and isocratically eluted using a mobile phase constituted of formate buffer/acetonitrile (95:5, v/v). Tranexamic acid was ionized by electrospray in positive mode. Parent [M + H]⁺ ions were m/z 158.0 for tranexamic acid and m/z 144.0 for IS. The most intense product ion of tranexamic acid (m/z 122.7) and IS (m/z 126.0) were used for quantification.ResultsThe assay was accurate and precise over the range of 1.0 (lower limit of quantification) to 200.0 µg/mL (upper limit of quantification), and has been successfully applied to study the clinical pharmacokinetics in two volunteers undergoing cardiac surgery.ConclusionA reliable method for quantification of tranexamic acid for analysis in clinical studies was obtained.     

Development of a Skeletal Muscle Mimic Phantom Compatible with QCT and MR Imaging

ObjectiveThe purpose of this study was to develop a skeletal muscle mimic phantom compatible with quantitative computed tomography (QCT) and magnetic resonance imaging, yielding physiologically appropriate values.MethodsAgar-based phantoms contained varying concentrations of CuCl₂ and EDTA to adjust T2 relaxation time and phantom density concurrently. T2 relaxation times were quantified using a 4-mm single-slice fast spin echo sequence repeated for six serial echo times at 937-μm resolution. T2 relaxation maps were generated using the Levenberg-Marquardt equation. A peripheral QCT scanner measured linear attenuation coefficients of phantoms, which were converted to density (mg/cm3) values. Five 2.3 ± 0.5 mm thick slices were acquired at 15 mm/s scan speed and 500-μm resolution. Logarithmic or linear regression models were fitted to EDTA or CuCl₂ versus density and T2 relaxation data.ResultsDensity (D) was linearly dependent on CuCl₂ (D = 0.27 [CuCl₂] + 63.92, R² = 0.84, P = 0.01) and invariant to EDTA. T2 relaxation time was related negatively to CuCl₂ (T2 = −10.13 ln [CuCl₂] + 66.70, R² = 0.91, P < .01) and positively to EDTA (T2 = 5.72 ln [EDTA] + 54.47, R² = 0.86, P < .01). Reproducibility within and between phantoms of the same compositions was acceptable (<5% error). Long-term stability was achieved for density but poorer for T2 relaxation time.ConclusionsThis phantom optimization method provides a means for altering a soft tissue phantom suited for calibrating magnetic resonance imaging and QCT signals within values representative of muscle. Phantoms can be used during scans for calibrating magnetic resonance signals between and within individuals over time and can cross-calibrate different scanners.     

Performances and Limitations of Several Ultrasound-Based Elastography Techniques: A Phantom Study

The objective of this study is to assess strain and shear wave (SW) elastography performance in terms of accuracy by performing in vitro measurements on a calibrated elastography phantom. Acquisitions were done on a phantom containing 4 inclusions (12–74 kPa) embedded in a homogeneous background material (30 kPa). We performed qualitative assessment on elastograms, semiquantitative assessment with strain or elasticity ratios between each inclusion and the background and quantitative evaluation with SW acquisitions. Ratio and elasticity estimations were compared with expected values. Biases, relative errors and 95% confidence intervals (95% CI) were calculated. All techniques adequately classified inclusions as harder or softer than the background. For stiffness ratio estimation, SW methods were more precise than strain methods and had significantly higher percentages of correctly classified measurements (p = 0.008). Quantitative stiffness measurements were reproducible despite constant biases. SW elastography methods provide more reproducible estimations of tissue stiffness ratio than strain methods, as well as reproducible quantitative tissue stiffness despite constant biases.     

Impact of Contralateral Breast Shielding on the Risk of Developing Radiation-induced Cancer from Full-field Digital Mammography Screening

ObjectiveThe objective of this study was to investigate the impact of contralateral breast shielding on the risk of developing radiation-induced cancer from four-view full-field digital mammography (FFDM) screening.MethodsA poly methyl methacrylate-polyethylene breast phantom and adult ATOM dosimetry phantom were used to measure organ dose on four FFDM machines using craniocaudal and mediolateral oblique projections for each breast. A lead rubber shield of 0.25 mm equivalent lead thickness was used to protect the contralateral breast. Organs dose, effective dose, and effective risk were calculated. For effective risk estimations, the impact of the shield was considered for the routine screening views.ResultsThe contralateral breast dose was reduced by more than 95%. For each FFDM machine, contralateral breast dose reduction in μGy were 35.20 reduced to 1.93, 41.40 reduced to 0.01, 22.85 reduced to 1.24, and 22.76 reduced to 1.66. Effective risk reduction was significant (P < .05). For all FFDM machines, a small reduction was identified in sternum bone marrow dose due to the use of contralateral breast shield.ConclusionsThe results of the study demonstrate the value of a contralateral breast shield. More research is required to determine whether such a shield has clinical utility.     

Attention to Threat in Anxiety-prone Individuals: Mechanisms Underlying Attentional Bias

Cognitive views on anxiety have proposed that attentional biases towards threatening information in high trait anxious individuals play an important role in the maintenance of anxiety and may even cause the development of clinical anxiety disorders. However, the precise nature of these attentional biases is under debate. In a pictorial version of the dot probe task, two accounts of attention to threat were contrasted and the components of attention involved in orienting to threat were assessed. Overall, the results support the view that all individuals orient to highly threatening pictures, with high trait anxious individuals orienting more strongly to moderately threatening pictures than the low trait anxious individuals. Attentional bias to threat in high trait anxious individuals was caused by attentional disengagement from threat. These results are discussed in relation to cognitive models of attention to threat.

Effects of cardiopulmonary resuscitation on direct versus video laryngoscopy using a mannequin model

IntroductionDuring the last decade, guidelines for cardiopulmonary resuscitation has shifted, placing chest compressions and defibrillation first and airway management second. Physicians are being forced to intubate simultaneously with uninterrupted, high quality chest compressions. Using a mannequin model, this study examines the differences between direct and video laryngoscopy, comparing their performance with and without simultaneous chest compressions.MethodsFifty emergency medicine physicians were randomly assigned to intubate a mannequin six times, using direct laryngoscopy (DL) and with two video laryngoscopy (VL) systems, a C-MAC traditional Macintosh blade and a GlideScope hyperangulated blade, with and without simultaneous chest compressions. A total of 300 intubations were completed and variables including intubation times, accuracy, difficulty, success rates and glottic views were recorded.ResultsThe C-MAC VL system resulted in quicker intubations compared to DL (p = 0.007) and the GlideScope VL system (p = 0.039) during active chest compressions. Compared to DL, intubations were rated easier for both the C-MAC (p < 0.0001) and the GlideScope (p < 0.0001). Intubation failure rates were also higher when DL was used compared to either the C-MAC or GlideScope (p = 0.029). VL devices provided a superior overall Cormack-Lehane grade view compared to DL (p < 0.0001). The presence of chest compressions significantly impaired Cormack-Lehane views during direct laryngoscopy (p = 0.007). Chest compressions made the intubation more difficult under DL (p = 0.002) and when using the C-MAC (p = 0.031). Chest compressions also made ETT placement less accurate when using DL (p = 0.004).ConclusionUsing a mannequin model, the C-MAC conventional VL blade resulted in decrease intubation times compared with DL or the GlideScope hyperangulated VL blade system. Overall, VL out performed DL in terms of providing a superior glottic view, minimizing failed attempts, and improving physician's overall perception of intubation difficulty. Chest compressions resulted in worse Cormack-Lehane views and higher rates of inaccurate endotracheal tube placement with DL, compared to VL.     

Systematic radiation dose optimization of abdominal dual-energy CT on a second-generation dual-source CT scanner: assessment of the accuracy of iodine uptake measurement and image quality in an in vitro and in vivo investigations

Purpose

To assess the accuracy of iodine quantification in a phantom study at different radiation dose levels with dual-energy dual-source CT and to evaluate image quality and radiation doses in patients undergoing a single-energy and two dual-energy abdominal CT protocols.

Methods

In a phantom study, the accuracy of iodine quantification (4.5–23.5 mgI/mL) was evaluated using the manufacturer-recommended and three dose-optimized dual-energy protocols. In a patient study, 75 abdomino-pelvic CT examinations were acquired as follows: 25 CT scans with the manufacturer-recommended dual-energy protocol (protocol A); 25 CT scans with a dose-optimized dual-energy protocol (protocol B); and 25 CT scans with a single-energy CT protocol (protocol C). CTDI_vol and objective noise were measured. Five readers scored each scan according to six subjective image quality parameters (noise, contrast, artifacts, visibility of small structures, sharpness, overall diagnostic confidence).

Results

In the phantom study, differences between the real and measured iodine concentrations ranged from −8.8% to 17.0% for the manufacturer-recommended protocol and from −1.6% to 20.5% for three dose-optimized protocols. In the patient study, the CTDI_vol of protocol A, B, and C were 12.5 ± 1.9, 7.5 ± 1.2, and 6.5 ± 1.7 mGycm, respectively (p < 0.001), and the average image noise values were 6.6 ± 1.2, 7.8 ± 1.4, and 9.6 ± 2.2 HU, respectively (p < 0.001). No significant differences in the six subjective image quality parameters were observed between the dose-optimized dual-energy and the single-energy protocol.

Conclusion

A dose reduction of 41% is feasible for the manufacturer-recommended, abdominal dual-energy CT protocol, as it maintained the accuracy of iodine measurements and subjective image quality compared to a single-energy protocol.

     

Preface

Purpose

A novel electromagnetic tracking configuration was characterized and implemented for image-guided surgery incorporating C-arm fluoroscopy and/or cone-beam CT (CBCT). The tracker employed a field generator (FG) with an open rectangular aperture and a frame enclosure with two essentially hollow sides, yielding a design that presents little or no X-ray attenuation across the C-arm orbit. The “Window” FG (WFG) was characterized in comparison with a conventional “Aurora” FG (AFG), and a configuration in which the WFG was incorporated directly into the operating table was investigated in preclinical phantom studies.

Method

The geometric accuracy and field of view (FOV) of the WFG and AFG were evaluated in terms of target registration error (TRE) using an acrylic phantom on an (electromagnetic compatible) experimental bench. The WFG design was incorporated in a prototype operating table featuring a carbon fiber top beneath, which the FG could be translated for positioning under the patient. The X-ray compatibility was evaluated using a prototype mobile C-arm for fluoroscopy and CBCT in an anthropomorphic chest phantom. The susceptibility to EM field distortion associated with surgical tools (e.g., spine screws) and the C-arm itself was investigated in terms of TRE, and calibration methods were tested to provide robust image-world registration with minimal perturbation from the rotational C-arm.

Results

The WFG demonstrated mean TRE of 1.28 ± 0.79 mm compared to 1.13 ± 0.72 mm for the AFG, with no statistically significant difference between the two (p = 0.32 and n = 250). The WFG exhibited a deeper field of view by ~10 cm providing an equivalent degree of geometric accuracy to a depth of z ~55 cm, compared to z ~45 cm for the AFG. Although the presence of a small number of spine screws did not degrade tracker accuracy, the mobile C-arm perturbed the electromagnetic field sufficiently to degrade TRE; however, a calibration method was identified to mitigate the effect. Specifically, the average calibration between posterior–anterior and lateral orientations of the C-arm was found to yield fairly robust registration for any C-arm pose with only a slight reduction in geometric accuracy (1.43 ± 0.31 mm in comparison with 1.28 ± 0.79 mm, p = 0.05). The WFG demonstrated reasonable X-ray compatibility, although the initial design of the window frame included suboptimal material and shape of the side bars that caused a level of streak artifacts in CBCT reconstructions. The streak artifacts were of sufficient magnitude to degrade soft-tissue visibility in CBCT but were negligible in the context of high-contrast imaging tasks (e.g., bone visualization).

Conclusion

The open frame of the WFG offers a potentially valuable configuration for electromagnetic trackers in image-guided surgery applications that are based on X-ray fluoroscopy and/or CBCT. The geometric accuracy and FOV are comparable to the conventional AFG and offers increased depth (z-direction) FOV. Incorporation directly within the operating table offers a streamlined implementation in which the tracker is in place but “invisible,” potentially simplifying tableside logistics, avoidance of the sterile field, and compatibility with X-ray imaging.     

Evaluating the Performance of Augmented Reality in Displaying Magnetic Resonance Imaging–Derived Three-Dimensional Holographic Models

Introduction/BackgroundEstablishing accuracy and precision of magnetic resonance (MR)–derived augmented reality (AR) models is critical before clinical utilization, particularly in preoperative planning. We investigate the performance of an AR application in representing and displaying MR-derived three-dimensional holographic models.MethodsThirty gold standard (GS) measurements were obtained on a magnetic resonance imaging (MRI) phantom (six interfiducial distances and five configurations). Four MRI pulse sequences were obtained for each of the five configurations, and distances measured in Picture Archiving and Communication System (PACS). Digital imaging and communications in medicine files were translated into three-dimensional models and then loaded onto a novel AR platform. Measurements were also obtained with the software's AR caliper tool. Significant differences among the three groups (GS, PACS, and AR) were assessed with the Kruskal–Wallis test and nonsample median test. Accuracy analysis of GS vs. AR was performed. Precision (percent deviation) of the AR-based caliper tool was also assessed.ResultsNo statistically significant difference existed between AR and GS measurements (P = .6208). PACS demonstrated mean squared error (MSE) of 0.29%. AR digital caliper demonstrated an MSE of 0.3%. Three-dimensional T2 CUBE AR measurements using the platform's AR caliper tool demonstrated an MSE of 8.6%. Percent deviation of AR software caliper tool ranged between 1.9% and 3.9%.DiscussionAR demonstrated a high degree of accuracy in comparison to GS, comparable to PACS-based measurements. AR caliper tool demonstrated overall lower accuracy than with physical calipers, although with MSE <10% and greatest measured difference from GS measuring <5 mm. AR-based caliper demonstrated a high degree of precision.ConclusionThere was no statistically significant difference between GS measurements and three-dimensional AR measurements in MRI phantom models.     

The impact of ASiR-V on abdominal CT radiation dose and image quality – A phantom study

IntroductionTo investigate how ASiR-V and kVp changes in Computed tomography (CT) affect radiation dose and image quality, when using automatic tube current modulation (ATCM) for different sized phantoms.MethodsA liver-phantom with two different liver inserts (QRM, Moehrendorf, Germany), with extension rings, representing fat, were additionally applied to the phantom to simulate patients of different sizes (small: 30cm diameter, medium: 35cm and large: 40cm). Abdominal scans were performed on a 256 slice CT scanner (GE Healthcare, Milwaukee, WI, USA), with consistent pitch (0.992), rotation time (0.5s), slice thickness (0.625mm) and collimation (80mm), while other parameters were varied (kVp: 80/100/120/140; Noise Index: 13/22; mA interval 80-720, ASiR-V: 30/60/100%). CTDI and DLP was recorded for each scan and image quality was assessed using objective metrics in predefined anatomic areas (HU and noise). Radiation dose and image quality metrics were compared between protocols.ResultsCTDI decreased by 80% from ASIR-V 30% to ASiR-V 100% for prescribed NI 13, and by 79% for the prescribed NI of 22. For 100% ASiR-V and a prescribed NI of 22 the CTDI remained the same regardless of phantom size for the different kVp settings. Pairwise comparison revealed significant differences in CTDI (p < 0.0001) for all combinations of prescribed NI and ASIR-V levels, except the difference between ASIR-V levels of 30 and 60%, with a prescribed NI of 13 (p = 0.124).When data from the three phantom sizes were combined, increasing ASIR-V from 30-100%, resulted in noise decreases of 22% for NI of 13 and by 8% for NI of 22. Notably, image quality in the low contrast area of the liver insert was impaired when the large phantom was scanned with 100% ASiR-V and either 80/100kVp (NI 22), because of the large reduction in tube current applied (down to 80 mA).ConclusionSubstantial radiation dose reductions (up to 80%) resulted from increasing ASiR-V levels. However, image quality deteriorates when 100% ASiR-V is applied due to low applied tube current by the ATCM.     

Radiation dose from digital breast tomosynthesis screening – A comparison with full field digital mammography

ObjectivesTo compare Mean Glandular Dose (MGD) and effective dose from digital breast tomosynthesis (DBT) screening with that from full field digital mammography (FFDM) screening.MethodTo simulate compressed breasts, two Perspex-polyethylene breast phantoms were used, one phantom for compressed breast in craniocaudal and the other for compressed breast in mediolateral oblique. An adult ATOM dosimetry phantom was loaded with high sensitivity thermoluminescence dosimeters; the phantom was then positioned on Hologic Selenia Dimensions mammographic machine to imitate DBT and 4-view FFDM screening. Organ radiation doses were measured from 4-view DBT and 4-view FFDM (craniocaudal and mediolateral oblique views for each breast). Organ radiation doses were used to calculate effective dose from one screening session.ResultsMGD for DBT was 3.6 mGy; MGD for FFDM was 2.8 mGy. For DBT, other organs (e.g. thymus, lungs, salivary glands, thyroid, contralateral breast and bone marrow) radiation dose was also higher than for FFDM. The use of DBT for breast cancer screening increases the effective dose (E) of one screening session by 22%. E for DBT was 0.44 mSv; E for FFDM was 0.34 mSv.ConclusionThe use of DBT for breast cancer screening increases the radiation dose to screening clients.     

Precision analysis of a quantitative CT liver surface nodularity score

Purpose

To evaluate precision of a software-based liver surface nodularity (LSN) score derived from CT images.

Methods

An anthropomorphic CT phantom was constructed with simulated liver containing smooth and nodular segments at the surface and simulated visceral and subcutaneous fat components. The phantom was scanned multiple times on a single CT scanner with adjustment of image acquisition and reconstruction parameters (N = 34) and on 22 different CT scanners from 4 manufacturers at 12 imaging centers. LSN scores were obtained using a software-based method. Repeatability and reproducibility were evaluated by intraclass correlation (ICC) and coefficient of variation. Using abdominal CT images from 68 patients with various stages of chronic liver disease, inter-observer agreement and test–retest repeatability among 12 readers assessing LSN by software- vs. visual-based scoring methods were evaluated by ICC.

Results

There was excellent repeatability of LSN scores (ICC:0.79-0.99) using the CT phantom and routine image acquisition and reconstruction parameters (kVp 100–140, mA 200–400, and auto-mA, section thickness 1.25–5.0 mm, field of view 35–50 cm, and smooth or standard kernels). There was excellent reproducibility (smooth ICC: 0.97; 95% CI 0.95, 0.99; CV: 7%; nodular ICC: 0.94; 95% CI 0.89, 0.97; CV: 8%) for LSN scores derived from CT images from 22 different scanners. Inter-observer agreement for the software-based LSN scoring method was excellent (ICC: 0.84; 95% CI 0.79, 0.88; CV: 28%) vs. good for the visual-based method (ICC: 0.61; 95% CI 0.51, 0.69; CV: 43%). Test–retest repeatability for the software-based LSN scoring method was excellent (ICC: 0.82; 95% CI 0.79, 0.84; CV: 12%).

Conclusion

The software-based LSN score is a quantitative CT imaging biomarker with excellent repeatability, reproducibility, inter-observer agreement, and test–retest repeatability.

     

Diffraction-enhanced Synchrotron Imaging of Bovine Ovaries Ex Vivo

ObjectivesThe objective of this study was to test the hypothesis that diffraction-enhanced imaging (DEI), a synchrotron x-ray imaging technique, would provide greater contrast for evaluating bovine ovaries compared with conventional diagnostic ultrasonography.Materials and MethodsBovine ovaries were evaluated ex vivo as follows: fresh without radiographic arterial contrast (n = 2), fresh with contrast (n = 1), preserved in 10% formalin without contrast (n = 2), and preserved with contrast (n = 1). Each ovary was imaged with DEI and subsequently with ultrasonography and histology. The ability to visualize and differentiate preantral and antral follicles, corpora lutea (CL), and cumulus oocyte complexes (COCs) were compared using DEI, ultrasonography, and histology. The diameter of follicles and CL were measured and compared using ultrasonography, DEI, and histology. The diameter of the smallest follicle detected was reported using each of the three imaging methods. The number of antral follicles (antral follicle count ≥2 mm) was compared between ultrasonography and DEI.ResultsDEI enabled the detection of 71% of follicles and 67% of CL that were detected ultrasonographically. However, DEI did not allow the detection of COCs and cell layers of the follicle wall that were visualized histologically. Luteal tissues were not easily distinguished using DEI, and DEI was inferior for differentiating follicles and CL compared with ultrasonography. The mean follicle diameter was similar between DEI (4.00 ± 0.35 mm, fresh with contrast; 9.62 ± 2.43 mm, fresh without contrast) and ultrasonography (3.85 ± 0.28 mm, fresh with contrast; 8.97 ± 2.60 mm, fresh without contrast) (P > .05). However, the mean follicle diameter was greater using both DEI (4.00 ± 0.35 mm) and ultrasonography (3.85 ± 0.28 mm) compared with histology (2.21 ± 0.38 mm; P = .01, fresh ovaries with contrast). The mean CL diameter was similar between DEI (11.64 ± 1.67 mm), ultrasonography (9.34 ± 0.35 mm), and histology (9.59 ± 0.36 mm) (P > .05). The mean diameter of the smallest follicle detected was similar between DEI (3.06 ± 0.45 mm) and ultrasonography (2.95 ± 0.74 mm); both DEI and ultrasonographic measurements were greater than histology (0.39 ± 0.04 mm, P < .0001). The mean antral follicle count was similar between ultrasonography (6.50 ± 0.71 mm, fresh with no contrast; 6.50 ± 2.50 mm, preserved with no contrast) and DEI (4.50 ± 0.50 mm, fresh with no contrast; 6.50 ± 0.50 mm, preserved with no contrast) (P > .05).ConclusionsThe contrast resolution of antral follicles, CL, and COCs in bovine ovaries was inferior using DEI compared with ultrasonography and histology. Alternative synchrotron techniques, such as phase-contrast computed tomography and DEI computed tomography, may prove more effective than DEI for imaging ovaries ex vivo.     

Augmented screws in angular stable plating of the proximal humerus: What to do when revision is needed?

BackgroundBone cement augmentation of modified cannulated locking screws shows biomechanically and clinically good results for osteoporotic fracture management. Nevertheless, complications need to be considered. Therefore implant removal should be tested for feasibility.MethodsImplant removal was simulated in 7 pairs of osteoporotic cadaveric humeri: During screw removal from an angular stable proximal humerus plate, we measured the maximum torque of 14 augmented screws and the corresponding 14 non-augmented screws on the contralateral humeri. After screw removal, specimens were cut along the screw axes to macroscopically investigate the impact of screw removal on the surrounding bone. In addition, we established a technique for cement removal in cases in which the screw head is obstructed with cement and therefore disables the insertion of the screwdriver.FindingsThe screw extraction torque measurements showed no significant differences between the two groups regarding one screw (screw 4 augmented: 1.52 Nm, SD 0.25 Nm vs. screw 4 non-augmented: 1.80 Nm, SD 0.40 Nm; P = 0.20), whereas torque values for the second screw in the augmented group were lower than in the control group (screw 5 augmented: 0.72 Nm, 0.31 Nm vs. screw 5 non-augmented: 1.42 Nm, 0.52 Nm; P = 0.009). Macroscopy of the bone showed no damage to the trabeculae within the humeral head due to the removal.InterpretationThe removal of cannulated, polymethylmethacrylate-augmented, 2.8 mm titanium screws from an angular stable plate was uncomplicated, without the need for special instruments or increased torque for screw removal. No additional damage was visible at the bone-cement interface.     

Influence of pilot hole diameter in cancellous screw fixation in a reduced density animal bone model

BackgroundScrew fixation in osteoporotic bone is clinically challenging. Screw failure rates are growing due to an increasing prevalence of osteoporosis. To address this, biomechanical models are needed to recreate the bone clinically encountered alongside the development of new operative techniques. The first aim of this study was to test whether the use of a smaller than recommended pilot-hole diameter improved pull-out strength for cancellous screws, with the second aim to create a model of low-density porcine bone for biomechanical testing.MethodsThirty porcine tibiae were cut into transverse metaphyseal sections of 20 mm thickness. Bone density was altered using 0.15 M Hydrochloric acid, and measured and pre- and post-demineralisation using HRμCT. Seventy-two screw areas were randomised to either 2.5 mm or 1.5 mm pilot holes and to either be normal or reduced density. Maximum axial pull-out strength was measured.FindingsDemineralisation reduced bone density by 12% (p < 0.0001) and 11% (p < 0.0001) for 2.5 mm and 1.5 mm pilot hole diameters respectively. Pull-out strength reduced by 50% (p = 0.0001) and 44% (p < 0.0001) following demineralisation for both 2.5 mm and 1.5 mm pilot hole diameters. Pull-out strength increased by 51% (p = 0.0008) when inserting screws into 1.5 mm pilot holes in low density bone, and by 28% (p = 0.027) in normal bone.InterpretationPorcine bone can be demineralised to model low density cancellous bone. This novel model showed that pullout force is significantly reduced in lower density screw holes, but that this reduction can be mitigated by reducing pilot hole diameter for cancellous screws.     

Infrared Vein Imaging for Insertion of Peripheral Intravenous Catheter for Patients Requiring Isolation for Severe Acute Respiratory Syndrome Coronavirus 2 Infection: A Nonrandomized Clinical Trial

IntroductionEstablishing intravenous access is essential but may be difficult to achieve for patients requiring isolation for severe acute respiratory syndrome coronavirus 2 infection. This study aimed to investigate the effectiveness of an infrared vein visualizer on peripheral intravenous catheter therapy in patients with coronavirus disease 2019.MethodsA nonrandomized clinical trial was performed. In total, 122 patients with coronavirus disease 2019 who required peripheral intravenous cannulation were divided into 2 groups with 60 in the control group and 62 in the intervention group. A conventional venipuncture method was applied to the control group, whereas an infrared vein imaging device was applied in the intervention group. The first attempt success rate, total procedure time, and patients’ satisfaction score were compared between the 2 groups using chi-square, t test, and z test (also known as Mann-Whitney U test) statistics.ResultsThe first attempt success rate in the intervention group was significantly higher than that of control group (91.94% vs 76.67%, ?² = 5.41, P = .02). The procedure time was shorter in the intervention group (mean [SD], 211.44 [68.58] seconds vs 388.27 [88.97] seconds, t = 12.27, P < .001). Patients from the intervention group experienced a higher degree of satisfaction (7.5 vs 6, z = ?3.31, P < .001).DiscussionPeripheral intravenous catheter insertion assisted by an infrared vein visualizer could improve the first attempt success rate of venipuncture, shorten the procedure time, and increase patients’ satisfaction.     

The Use of Therapeutic Inhaled Essential Oils (TIEO) as a Holistic Approach to Decrease Preoperative Anxiety in ERAS Gynecological Surgery

IntroductionPreoperative anxiety is a negative symptom frequently experienced by surgical patients. This evidence-based-practice (EBP) project evaluated the effectiveness of therapeutic inhaled essential oils (TIEO) on anxiety levels during the preoperative phase of surgery in enhanced recovery after surgery (ERAS) gynecological patients ages 18 to 65 years old.MethodsA prospective, preposttest, quasiexperimental design was used to evaluate preoperative anxiety scores. Patients (N = 53) scheduled for gynecological surgeries were enrolled at a level II trauma center. Upon arrival to the preoperative area on the day of surgery, patients were asked to score their anxiety level using the Visual Analog Scale for Anxiety (VAS-A). Patients were provided the TIEO intervention during their preoperative phase of surgery ranging from 15 to 60 minutes. Patients were encouraged to take mindful deep breaths and inhale the essential oil vapor. Before being transported into the operating room, patients were asked to re-evaluate their anxiety level using the VAS-A.ResultsA matched paired t-test revealed the post-VAS-A measurements were significantly lower (n = 52, M = 31.37, SD = 24.334) than the pre-VAS-A measurements (n = 52, M = 53.50, SD = 26.863), t₅₁ = 8.756, P = .000). On average, postanxiety scores were 22.135 mm lower than pre-anxiety scores (95% CI [17.060, 27.209]).ConclusionsThe use of TIEO demonstrated a statistically significant decrease in preoperative anxiety scores within the ERAS gynecological population. TIEO can be used as an adjunct intervention to manage preoperative anxiety. TIEO can be successfully administered in the preoperative area. Decreasing anxiety in the preoperative period may lead to many perioperative benefits such as improving surgical outcomes, patient satisfaction, and quality of care.     

Quantitative Bone Ultrasound at the Distal Radius in Adults with Cystic Fibrosis

It is of clinical importance to identify bone disease related to cystic fibrosis (CF) early in its course to allow therapeutic interventions that optimize bone health. To test the technical (precision) and clinical (percentage of abnormal results, correlation with clinical parameters) performance of a commercial quantitative ultrasound apparatus for radial measurements, speed of sound (SOS) was measured at the distal third of the left radius with the Omnisense 7000p apparatus (Sunlight Medical, Tel-Aviv, Israel) in a group of young adult CF patients with regular follow-up at the Brussels and Ghent University Hospital. Sixty-three (37 males) CF patients at a median (range) age of 23.5 y (18.1–39.9) were included. SOS, SOS z-score and SOS t-score were respectively 4017 ± 97 m/s, −0.31 ± 0.74 and −0.60 ± 0.78 in males and 4086 ± 97 m/s, −0.19 ± 0.75 and −0.51 ± 0.95 in females. Mean SOS t-score was significantly lower compared with the manufacturer's reference data for males (p < 0.0001) and females (p = 0.01). SOS z- and t-scores correlated with weight z-score and body mass index z-score in females. No significant correlation was found between SOS and forced expiratory volume in 1 s (%). Neither diabetes mellitus nor liver disease was found to influence SOS. Radial quantitative ultrasound has a precision of 0.55%. The SOS is in the low normal range in 14% of CF patients and is influenced by weight in female patients, but not by the severity of the lung disease.     

Preliminary ultrasound evaluation of the rotator cable in asymptomatic volunteers

PurposeTo characterize the rotator cable high-resolution ultrasound appearance in asymptomatic shoulders of volunteers of different age.Materials and methodsIRB approval and volunteers’ written consent was obtained. Excluding subjects with known shoulder affections, we screened 24 asymptomatic volunteers. Supraspinatus and infraspinatus tendons high-resolution ultrasound evaluation was performed according to standard scan protocols, further excluding shoulders with partial/full-thickness cuff tears. Thus, we studied 24 shoulders in 12 young volunteers (age range 21–39 years, mean age 33 ± 8 years) and 21 shoulders in 11 elderly volunteers (age range 62–83 years, mean age 75 ± 45 years). For each shoulder, we noted rotator cable visibility and its thickness and width. Fisher’s and U Mann–Whitney statistics were used.ResultsRotator cable was less frequently detected in young than in elderly volunteers (5/24 vs. 11/21 shoulders; P = 0.034). When detected, rotator cable was significantly thicker in young (range 1.2–1.5 mm, mean thickness 1.3 ± 0.1 mm) than in elderly (range 0.9–1.4 mm, mean thickness 1.2 ± 0.1 mm) volunteers (P = 0.025), while its width was not significantly different in young (range 4.5–7.1 mm, mean 5.6 ± 1.1 mm) compared to elderly (range 2.5–7.1 mm, mean 4.2 ± 1.4 mm) volunteers (P = 0.074) although a tendency can be highlighted.ConclusionsUltrasound demonstrated the different consistency of rotator cable in young and elderly asymptomatic patients, with high interobserver reproducibility.