Independent Observers Research Articles

Is 18F-fluoride PET/CT an Accurate Tool to Diagnose Loosening After Total Joint Arthroplasty?

Several studies using positron emission tomography (PET) show highly elevated periprosthetic bone uptake of fluorine-18 sodium fluoride (18F-fluoride), suggestive of implant loosening after arthroplasty. Focus so far has been on qualitative but not on quantitative assessment. There is also a lack of intraoperative confirmation of preoperative 18F-fluoride PET findings. Although the method seems to have acceptable accuracy and high sensitivity, an attempt to improve the specificity and an overall validation of the method appear warranted. (1) Is there a difference in 18F-fluoride uptake around loose versus well-fixed THA and TKA components? (2) Can 18F-fluoride uptake measures provide a threshold that differentiates loose from well-fixed implants undergoing revision for a variety of septic and aseptic indications? (3) In a population restricted to THA and TKA undergoing revision for aseptic indications, can measurement of 18F-fluoride uptake still distinguish loose from well-fixed components? (4) What is the interrater reliability of measuring 18F-fluoride uptake? This was a retrospective assessment of a diagnostic test, 18F-fluoride PET/CT, which was performed prior to revision surgery. We included 63 patients with 31 THAs and 32 TKAs. Sixty-five percent of patients were female, and the mean age at 18F-fluoride PET/CT was 66 years. The THA had different modes of fixation (cemented, cementless, and hybrid; 45%, 32%, and 23%, respectively), whereas all TKAs were cemented. Imaging was conducted using routine protocols 1 hour after tracer injection. The interobserver reproducibility was analyzed using Spearman rank correlations and Bland-Altman analyses. Two independent observers were trained separately by a nuclear physician to measure maximal periprosthetic standardized uptake values (SUVmax) for each arthroplasty component (n = 126). Findings at surgery (whether the components were well fixed or loose, as well as the presence or absence of infection) were used as a reference. Presence of periprosthetic joint infection was retrospectively determined based on the criteria suggested by the European Bone and Joint Infection Society (EBJIS): clinical features in combination with blood analysis, synovial fluid cytologic analysis, and microbiology test results. Receiver operating characteristic (ROC) curves were plotted to assess the area under the curve (AUC) for each investigated component separately, indicating suitable SUVmax thresholds that differentiate loose from well-fixed components. After excluding patients with confirmed or suspected PJI per the EBJIS criteria (n = 12), the above analysis was repeated for the remaining patients with aseptic loosening (n = 51). We found higher 18F-fluoride uptake around loose versus well-fixed components in all but femoral TKA components (median [range] SUVmax for well-fixed versus loose THA cups 10 [7 to 30] versus 22 [6 to 64], difference of medians 12; p = 0.003; well-fixed versus loose TKA femoral components 14 [4 to 41] versus 19 [9 to 42], difference of medians 5; p = 0.38). We identified favorable ROC curves for all investigated components except femoral TKA components (THA cups AUC 0.81 [best threshold 13.9]; THA femoral stems AUC 0.9 [best threshold 17.3]; femoral TKA components AUC 0.6 [best threshold 14.3]; tibial TKA components AUC 0.83 [best threshold 15.8]). 18F-fluoride was even more accurate at diagnosing loosening when we limited the population to those patients believed not to have prosthetic joint infection (THA cups AUC 0.87 [best threshold 14.2]; THA femoral stems AUC 0.93 [best threshold 15.0]; femoral TKA components AUC 0.65 [best threshold 15.8]; tibial TKA components AUC 0.86 [best threshold 14.7]). We found strong interrater correlation when assessing SUVmax values, with Spearman ρ values ranging from 0.96 to 0.99 and Bland-Altman plots indicating excellent agreement between the two independent observers. Measuring SUVmax after 18F-fluoride PET/CT is a useful adjunct in the diagnostic evaluation for suspected implant loosening after THA and TKA. The method appears to be both accurate and reliable in diagnosing implant loosening for all components except femoral TKA components. In a real-world mixed population with both low-grade infection and aseptic loosening, the method seems to be fairly easy to learn and helpful to subspecialized arthroplasty clinicians. When infection can be ruled out, the method probably performs even better. Further prospective studies are warranted to explore the reason why femoral TKA component loosening was more difficult to ascertain using this novel technique. Level III, diagnostic study.

Comparative analysis of methods for measuring root canal curvature based on periapical radiography: A laboratory study.

To evaluate the agreement between six currently available periapical radiography-based methods for measuring the root canal curvatures in mesial roots of mandibular first molars, assessed by two examiners with different proficiency levels. Non-endodontically treated mesial roots of 41 human mandibular first molars were radiographed using the parallelling technique. Two independent observers (a specialist in endodontics and radiology and a final-year dental student) assessed their root canal curvature using the methodologies described by Schneider (1971, Oral Surgery, Oral Medicine, Oral Pathology and Oral Radiology, 32, 271), Weine (1982, Endodontic therapy), Berbert and Nishiyama (1994, Revista Gaúcha de Odontología, 356), Luiten etal. (1995, Journal of Endodontics, 21, 26), Hankins and ElDeeb (1996, Journal of Endodontics, 22, 123) and Pettiette etal. (1999, Journal of Endodontics, 25, 230). Intra- and inter-examiner reliability was assessed using the intraclass correlation coefficient. The differences in curvature angle measured by the different methods were compared using the one-way anova for repeated measures test, followed by Tukey's post hoc analysis. The effect was calculated using the Cohen's d method. To determine the agreement between methods, the Bland-Altman analysis was used. The significance level was set at 5%. Agreement for the observers was excellent (>0.81) for the six methods considered. For the angle comparisons between methods, the maximum differences were for Schneider versus Weine (35.77°) and Luiten versus Hankins (35.14°), whilst the highest percentage of angles with a difference >10° were Weine versus Luiten and Berbert versus Pettiette (90%) and the comparison Weine versus Hankins presented with the lowest frequency (15%). Excellent agreement was found for five comparisons: Weine versus Luiten (0.940), Berbert versus Pettiette (0.917), Weine versus Pettiette (0.907), Luiten versus Pettiette (0.904) and Berbert versus Luiten (0.812). Compared to Schneider's method, the other methods showed a tendency of increasing difference as the angles became more acute. The other methods exhibited linear differences, remaining constant for smaller and larger angles. Reliability was excellent for all methods assessed separately. Maximum differences in curvature angles were found when comparing Schneider versus Weine and Luiten versus Hankins. Excellent agreement was found for Weine versus Luiten, Berbert versus Pettiette, Weine versus Pettiette, Luiten versus Pettiette and Berbert versus Luiten. In the presence of dilacerations, the method by Schneider was less sensitive.

Presenting a Long-Term, Reprocessed Dataset of Global Sea Surface Temperature Produced Using the OSTIA System

Over the past few decades, the oceans have stored the majority of the excess heat in the climate system resulting from anthropogenic emissions. An accurate, long-term sea surface temperature (SST) dataset is essential for monitoring and researching the changes to the global oceans. A variety of SST datasets have been produced by various institutes over the years, and here, we present a new SST data record produced originally within the Copernicus Marine Environment Monitoring Service (which is therefore named CMEMS v2.0) and assess: (1) its accuracy compared to independent observations; (2) how it compares with the previous version (named CMEMS v1.2); and (3) its performance during two major volcanic eruptions. By comparing both versions of the CMEMS datasets using independent in situ observations, we show that both datasets are within the target accuracy of 0.1 K, but that CMEMS v2.0 is closer to the ground truth. The uncertainty fields generated by the two analyses were also compared, and CMEMS v2.0 was found to provide a more accurate estimate of its own uncertainties. Frequency and vector analysis of the SST fields determined that CMEMS v2.0 feature resolution and horizontal gradients were also superior, indicating that it resolved oceanic features with greater clarity. The behavior of the two analyses during two volcanic eruption events (Mt. Pinatubo and El Chichón) was examined. A comparison with the HadSST4 gridded in situ dataset suggested a cool bias in the CMEMS v2.0 dataset versus the v1.2 dataset following the Pinatubo eruption, although a comparison with sparser buoy-only observations yielded less clear results. No clear impact of the El Chichón eruption (which was a smaller event than Mt. Pinatubo) on CMEMS v2.0 was found. Overall, with the exception of a few specific and extreme events early in the time series, CMEMS v2.0 possesses high accuracy, resolution, and stability and is recommended to users.

Microliposuction and Radiofrequency Combined With Fat Grating as a New Method for Hybrid-Type Nasolabial Folds.

The hybrid-type nasolabial fold is a special, complex type of nasolabial fold with various causes, making it difficult to obtain an ideal effect with a single treatment. This study aimed to investigate the effect and complications of a comprehensive therapy combining microliposuction, radiofrequency, and fat grafting on hybrid-type nasolabial folds. Twenty-one patients aged 27 to 45 (mean: 34.71±5.41) years, who underwent the therapy for hybrid-type nasolabial folds were retrospectively analyzed. All patients were followed up for 12 months. Two independent observers conducted postoperative follow-ups at 1 week and 12 weeks. One week postoperatively, the hematoma, mass nodule, and skin scald ecchymosis scores were 1.24±0.43, 1.62±0.58, and 1.48±0.59, respectively. At 12 weeks, the scores of mass nodules and skin scald ecchymosis decreased (1.19±0.39 and 1.05±0.21, respectively) without obvious hematoma. The WSRS grade decreased from 4.33±0.47 to 2.19±0.39 (P<0.001), and the hybrid-type nasolabial folds significantly improved. The Face-Q scale score was 20.43±2.63 points (standard score: 85.12±10.95 points). 76.19% of the patients scored more than 80 points in the subjective Face-Q evaluation. Microliposuction and radiofrequency combined with fat grafting effectively treats hybrid-type nasolabial folds, resulting in high patient satisfaction. Most complications can be prevented, and optimal outcomes can be obtained by comprehensive surgical methods and correct procedures, which is thus worthy of clinical promotion.

An open-source tool for automated human-level circling behavior detection

Quantitatively relating behavior to underlying biology is crucial in life science. Although progress in keypoint tracking tools has reduced barriers to recording postural data, identifying specific behaviors from this data remains challenging. Manual behavior coding is labor-intensive and inconsistent, while automatic methods struggle to explicitly define complex behaviors, even when they seem obvious to the human eye. Here, we demonstrate an effective technique for detecting circling in mice, a form of locomotion characterized by stereotyped spinning. Despite circling's extensive history as a behavioral marker, there currently exists no standard automated detection method. We developed a circling detection technique using simple postprocessing of keypoint data obtained from videos of freely-exploring (Cib2−/−;Cib3−/−) mutant mice, a strain previously found to exhibit circling behavior. Our technique achieves statistical parity with independent human observers in matching occurrence times based on human consensus, and it accurately distinguishes between videos of wild type mice and mutants. Our pipeline provides a convenient, noninvasive, quantitative tool for analyzing circling mouse models without the need for software engineering experience. Additionally, as the concepts underlying our approach are agnostic to the behavior being analyzed, and indeed to the modality of the recorded data, our results support the feasibility of algorithmically detecting specific research-relevant behaviors using readily-interpretable parameters tuned on the basis of human consensus.

A Physical‐Informed Neural Network for Improving Air‐Sea Turbulent Heat Flux Parameterization

AbstractThe parameterizations of air‐sea turbulent heat flux are one of the major bottlenecks in atmosphere‐ocean coupled model development, which play a crucial role in sea surface temperature (SST) prediction. Recently, neural networks start to be applied for the development of parameterizations of interface turbulent heat flux. However, these new parameterizations are primairily developed for specific regions and have not been tested in real atmosphere‐ocean coupled models. In this study, we propose a new air‐sea heat flux parameterization using a physical‐informed neural network (PINN) based on multiple observational data sets worldwide. Evaluated with an independent observation data set, it is shown that the PINN can significantly reduce the RMSE of latent heat flux by at least about 48.6% compared to three traditional bulk formulas. Moreover, the PINN can be flexibly updated with new observational data by transfer learning. To test the performance of the new parameterization in realistic application, we implement the PINN into a global ocean‐atmosphere coupled model and make seasonal forecasts for the first time. The PINN markedly reduce the errors of equatorial SST forecast, indicating a good performance of the PINN‐based air‐sea turbulent heat flux scheme. Noticeably, due to limited observational data, the NN‐based parameterizations tend to underestimate heat flux at high wind speeds compared with bulk formula‐based parameterizations. With more data available at extreme conditions, the PINN can be improved via transfer learning and need to be futher evaluated. This study suggests that PINN‐based air‐sea heat flux parameterization is promising to improve SST simulation.

Association of the Inlay Structure Used in the Modified Bristow Procedure With Accelerated Bone Union: Comparing the Cuistow and Modified Bristow Procedures.

The Chinese unique inlay Bristow (Cuistow) procedure is a modified Bristow surgery in which an inlay (mortise-and-tenon) structure is added to the contact surface between the coracoid tip and the glenoid. Patients who have undergone the Cuistow procedure have had satisfying clinical performance and excellent postoperative bone healing rates (96.1%). To compare the clinical and radiographic outcomes after the arthroscopic Cuistow procedure and the arthroscopic Bristow procedure. Cohort study; Level of evidence, 3. A total of 91 patients who underwent either the Cuistow or Bristow procedure between January 2017 and March 2018 were selected, and 69 patients (70 shoulders; 35 in the Cuistow group and 35 in the Bristow group) were included. Clinical assessment at minimum 24 months postoperatively, including the visual analog scale for pain and instability, American Shoulder and Elbow Surgeons score, Rowe score, subjective shoulder value score, and active range of motion, was completed by independent observers and compared with values collected preoperatively. Assessment with 3-dimensional computed tomography scans was performed preoperatively; immediately after the operation; at 3, 6, and 12 months postoperatively; and at the final follow-up. A total of 69 patients (70 shoulders) were included, with a mean follow-up duration of 34.41 ± 5.99 months (range, 24-50 months). Both groups saw significant improvement in visual analog scale for pain and instability, American Shoulder and Elbow Surgeons, Rowe, and subjective shoulder value scores at the final follow-up compared with the preoperative values (P < .001 for all), with no significant between-group differences on any clinical outcomes at the final follow-up. The 3-month postoperative graft union rate on computed tomography was significantly higher in the Cuistow group compared with the Bristow group (82.9% vs 51.4%, respectively, P = .003), although the graft union rate at the final follow-up was not significantly different (94.3% vs 85.7%, respectively; P = .449). Patients receiving the Cuistow procedure had equivalent clinical outcomes and a significantly higher bone union rate at 3 months postoperatively than those in the Bristow group. The inlay structure used in the Cuistow procedure was found to be associated with accelerated bone union.

Accuracy of smartphone imaging versus clinical examination in the diagnosis of ocular disorders in a rural-based hospital: A descriptive study

Background: In India, there is an unequal distribution of eye health care, and tele-ophthalmology promises to be a potential tool to provide accessible, affordable, and good-quality health care to the population residing in the rural and remote areas of our country. Aims: The aim of the study was to study the accuracy of smartphone imaging versus clinical examination in the diagnosis of ocular disorders at a rural-based hospital. Setting and Design: A hospital-based descriptive study was conducted for 18 months. The study was carried out in the outpatient department (OPD) of ophthalmology at a rural health training center (RHTC), attached to a tertiary care hospital. Materials and Methods: Inclusion-A routine examination was carried out in the ophthalmology OPD at the RHTC. The off-site assessment was done based on the smartphone camera (iPhone Xs Max) images and videos captured on-site, which were remotely shared with two independent blinded observers to make the diagnosis which was compared with the clinical (on-site) diagnosis. Statistical Analysis: The agreement between the expert’s finding and the clinical examination finding was determined using Light’s Kappa coefficient. Accuracy of the photographic method was carried out in terms of sensitivity and specificity, considering clinical findings as the gold standard. Results and Conclusion: The diagnostic accuracy of smartphone imaging was the highest for the diagnosis of cataracts, followed by anterior segment conditions. The clinical diagnosis and smartphone imaging agreement were almost perfect for anterior segment disorders, while it was moderate for glaucoma and other disc pathologies.

Plane-wave and cylindrical-wave acoustic reflection from a marine sediment with layering representative of the New England Mud Patch.

An analysis is presented of reflection from a marine sediment consisting of a homogeneous mud layer overlying a sand-mud basement, the latter with an upward-refracting, inverse-square sound speed profile. Such layering is representative of the sediment at the New England Mud Patch (NEMP). By applying appropriate integral transforms and their inverses to the Helmholtz equations for the ocean and the two sediment layers, along with the boundary conditions, a Sommerfeld-Weyl type of wavenumber integral is obtained for the cylindrical-wave reflection coefficient of the sediment, R. A stationary phase evaluation of this integral yields a closed-form expression for the plane-wave reflection coefficient, R0. In the absence of attenuation, the plane-wave solution exhibits total reflection up to a critical grazing angle, ac, but when attenuation in the sediment is introduced, the region of total reflection in |R0| is replaced by a sequence of contiguous peaks. With realistic levels of sediment attenuation, the cylindrical-wave solution, |R|, exhibits a quasi-critical grazing angle, less than ac, which is strongly dependent on the source-plus-receiver height above the seabed, which is mildly dependent on the depth of the mud layer but is essentially independent of frequency. Such behavior is consistent with independent experimental observations at the NEMP.

Retrospective radiographic study comparing unintentional extrusion of gutta-percha versus sealer on teeth with periapical radiolucency.

The purpose of the present study was the radiographic evaluation of endodontically treated teeth presenting periapical radiolucency and unintentional overfilling with gutta-percha or sealer on treatment outcome and persistence of the extruded materials. After assessment using periapical index (PAI), 202 roots filled with gutta-percha and zinc oxide-eugenol sealer (Roth 811, Roth International), exhibiting unintentional overfilling and periapical radiolucency were selected. All cases had at least 1 year of follow-up. Type of extruded material, periapical status, and removal/persistence of the extruded material were evaluated by two independent observers. Data were statistically analyzed using logistic and linear regression analysis. Tooth location (P .001), follow-up period (P .001), and type of extruded material (P &#61; .004) significantly influenced treatment outcomes. Specifically, posterior roots exhibited better outcomes compared to anterior, and cases with overfilling of sealer showed superior healing potential compared to those with gutta-percha overfilling. Additionally, longer recall periods were associated with improved treatment success. The type of extruded material (P .001) and follow-up period (P .001) significantly affected the presence of extruded material in the follow-up radiograph. The persistence of extruded material was greater when gutta-percha was extruded, and extruded materials were less detected when the follow-up period was longer. Teeth with periapical radiolucency and unintentional overfilling require longer follow-up intervals for effective monitoring of healing. Treatment outcome was associated with the type of extruded materials used in the present study. The persistence of those materials in the periapex did not affect healing.

Testing for finite variance with applications to vibration signals from rotating machines

In this paper we propose an algorithm for testing whether the independent observations come from finite-variance distribution. The preliminary knowledge about the data properties may be crucial for its further analysis and selection of the appropriate model. The idea of the testing procedure is based on the simple observation that the empirical cumulative even moment (ECEM) for data from finite-moments distribution tends to some constant whereas for data coming from heavy-tailed distribution, the ECEM exhibits irregular chaotic behavior. Based on this fact, in this paper we parameterize the regular/irregular behavior of the ECEM and construct a new test statistic. The efficiency of the testing procedure is verified for simulated data from three heavy-tailed distributions with possible finite and infinite variances. The effectiveness is analyzed for data represented in time domain. The simulation study is supported by analysis of real vibration signals from rotating machines. Here, the analyses are provided for data in both the time and time-frequency domains.

Estimation and inference in low frequency factor model regressions with overlapping observations

A low frequency factor model regression uses changes or returns computed at a lower frequency than data available. Using overlapping observations to estimate low frequency factor model regressions results in more efficient estimates of OLS coefficients and standard errors, relative to using independent observations or high frequency estimates. I derive the relevant inference and propose a new method to correct for the induced autocorrelation. I present a series of simulations and empirical examples to support the theoretical results. In tests of asset pricing models, using overlapping observations results in lower pricing errors, compared to existing alternatives.

Sex estimation using long bones in the largest burial site of the Copper Age: Linear discriminant analysis and random forest

Sex estimation of the individuals in a sample is fundamental for any bioarchaeological study to define a particular demographic assemblage or to classify isolated remains. Long bones are an excellent alternative for sex estimation when the most dimorphic anatomical parts are not preserved or are highly altered. Here we propose a set of discriminant functions and classification models to estimate the sex of prehistoric individuals using linear discriminant analysis and machine learning approaches. Different osteometric variables were taken from the humeri, ulnae, radii, femurs and tibias of a sample of 109 articulated skeletons buried in the collective tomb of Camino del Molino (Region of Murcia, SE-Spain), dated to the 3rd millennium BC. Sex was estimated based on standard anthropological methods and ancient DNA analysis of a control sample. Fifty-two discriminant functions with prediction thresholds higher than 0.8 on the ROC curve were obtained using independent (22) and combined variables (30). The best LDA models for sex prediction were those based on proximal epiphyseal widths or their combination with other variables, reaching values close to 0.98 on the ROC curve. The random forest-based model obtained an accuracy of 0.94 and confirmed the importance of epiphyseal widths in sex classification. This analysis is more comprehensive than univariate LDA, as it allows for ranking the importance of bones in sex discrimination and considers correlations between long bones rather than treating them as independent observations. In contrast, applying LDA to each bone makes it easier to predict the sex of other coeval collections that do not have such a complete sample. This work aims to overcome the scarcity of methods that can be applied to sex estimation of the large volume of isolated remains from Camino del Molino and for other Mediterranean skeletal series from the Late Prehistory with high biological affinity and that share similar environmental conditions.

Functional and Aesthetic Comparison between Grafts and Local Flaps in Non-Melanoma Skin Cancer Surgery of the Face: A Cohort Study

BackgroundNon-melanoma skin cancers represent more than 90 % of malignant skin tumors, with an incidence of 19.46 cases/100,000 people per year in Italy; however, their real incidence is underestimated. Although there are several therapeutic strategies, the only one that can guarantee a 95 % healing rate and the possibility of performing histological examination is surgical excision with subsequent reconstruction of the injured area with direct closure and with skin graft, local, regional, or free flaps in cases involving greater damage. Material and MethodsFifty-four patients underwent post-oncological head/face reconstructive surgery with skin graft or local flap between November 2021 and February 2023. The aesthetic outcomes (and the subsequent impact on the patients’ lives) were assessed using the Vancouver Scar Scale, Manchester Scar Scale, and Visual Analog Scale with scars ranked by three independent surgeon observers. ResultsPatients who received reconstruction with local flaps demonstrated improved aesthetic and functional satisfaction, as well as improved aesthetic evaluation by independent surgeons. ConclusionsThe use of local flaps permits a more pleasing reconstruction (functionally and aesthetically) of post-oncological tissue defects of the face.

Higher subfoveal choroidal thickness in choroidal melanomas than in choroidal nevi.

To compare subfoveal choroidal thickness (SFCT) between eyes with choroidal melanoma and choroidal nevi. Retrospective study of 126 consecutive patients in a tertiary ocular oncology center. Eyes with tumors located less than two disc-diameters from the fovea were excluded. In eyes with naevi, factors of potential transformation into melanoma were recorded (orange pigment, subretinal fluid, thickness >2 mm, diameter >5 mm, ultrasound hollowness). SFCT was assessed by 3 independent observers on horizontal spectral-domain OCT scans. Sixty-seven eyes with choroidal melanoma and 59 eyes with choroidal nevi were included. The melanoma and nevi groups did not differ in gender (P=0.14) nor age (P=0.34). There was a very good agreement between the three independent observers for SFCT measurements (intraclass correlation coefficient=0.89). Mean SFCT was higher in melanomas (294.3±89.9 µm) than naevi (260.3±76.7 µm) (P=0.013), and the difference remained significant between melanomas and 28 naevi with ≥2 growth risk factors (256.3±77.0 µm) (P=0.027). In a multivariate model, the significant contributors to SFCT were presence of melanoma (P=0.004), younger age (P<0.0001) and shorter lesion distance to the fovea (P=0.016). SFCT may reflect the interplay between melanocytic tumors and their choroidal microenvironment. Its clinical utility should be explored in future studies.

Artificial intelligence-assisted volume isotropic simultaneous interleaved bright- and black-blood examination for brain metastases.

To verify the effectiveness of artificial intelligence-assisted volume isotropic simultaneous interleaved bright-/black-blood examination (AI-VISIBLE) for detecting brain metastases. This retrospective study was approved by our institutional review board and the requirement for written informed consent was waived. Forty patients were included: 20 patients with and without brain metastases each. Seven independent observers (three radiology residents and four neuroradiologists) participated in two reading sessions: in the first, brain metastases were detected using VISIBLE only; in the second, the results of the first session were comprehensively evaluated by adding AI-VISIBLE information. Sensitivity, diagnostic performance, and false positives/case were evaluated. Diagnostic performance was assessed using a figure-of-merit (FOM). Sensitivity and false positives/case were evaluated using McNemar and paired t-tests, respectively. The McNemar test revealed a significant difference between VISIBLE with/without AI information (P < 0.0001). Significantly higher sensitivity (94.9 ± 1.7% vs. 88.3 ± 5.1%, P = 0.0028) and FOM (0.983 ± 0.009 vs. 0.972 ± 0.013, P = 0.0063) were achieved using VISIBLE with AI information vs. without. No significant difference was observed in false positives/case with and without AI information (0.23 ± 0.19 vs. 0.18 ± 0.15, P = 0.250). AI-assisted results of radiology residents became comparable to results of neuroradiologists (sensitivity, FOM: 85.9 ± 3.4% vs. 90.0 ± 5.9%, 0.969 ± 0.016 vs. 0.974 ± 0.012 without AI information; 94.8 ± 1.3% vs. 95.0 ± 2.1%, 0.977 ± 0.010 vs. 0.988 ± 0.005 with AI information, respectively). AI-VISIBLE improved the sensitivity and performance for diagnosing brain metastases.

Axial rod slip at the end-of-construct screw in scoliosis surgery: relevance, occurrence and prevention

PurposeDespite standardized biomechanical tests for spinal implants, we recently recognized pedicle screw failure to maintain the rod fixated as a clinical concern in scoliosis surgery. This occurrence study investigates the risk and magnitude of axial rod slip (ARS), its relation with technique and preventive measures.MethodsRetrospective multicenter review of all primary scoliosis cases (2018–2020) with > 1 year FU from three centers, instrumented with uniplanar screws and 5.5 mm CoCr rods (Mesa 2, Stryker Corporation, Kalamazoo, MI, USA). ARS was defined as > 1 mm change in residual distal rod length from the screw in the lowest instrumented vertebra (LIV) and assessed by two independent observers. Slip distance, direction, relation to distal screw density and time of observation were recorded, as well as the effect of ARS on caudal curve increase. To prevent slip, more recent patients were instrumented with a different end-of-construct screw (Reline, NuVasive Inc. San Diego, CA, USA) and analyzed for comparison.ResultsARS risk was 27% (56/205) with a distance of 3.6 ± 2.2 mm, predominantly convex. 42% occurred before 4 months, the rest before 1 year. The caudal curve substantially increased three times more often in patients with ARS. Interobserver reliability was high and slip was in the expected direction. ARS was unrelated to distal screw density. Remarkable variation in ARS rates (53%, 31%, 13%) existed between the centers, while there was no difference in mean screw density (≈1.3 screws/level) or curve correction (≈60%). Revision surgery for ARS was required in 2.9% (6/207). Using the different end-of-construct screw, ARS risk was only 2% (1/56) and no revisions were required.ConclusionThis study demonstrates the prevalence of axial rod slip at the end of construct in scoliosis surgery and its clinical relevance. While minimal ARS can be subclinical, ARS should not be mistaken for adding on. The most severe ARS predominantly occurred convex at the high-loaded distal screw when L3 was the LIV. Longer constructs (LIV L3 or L4) have a higher risk of ARS. The minimal risk of ARS with another end-of-construct screw underscores the influence of screw type on ARS occurrence in our series. Further research is essential to refine techniques and enhance patient outcomes.

The effects of alfaxalone on cardiac and pulmonary vascular size in cats evaluated by thoracic radiography and echocardiography.

Alfaxalone is a neuroactive steroid that modulates the GABAA receptor, which has shown recent widespread use as a sedative and anesthetic agent in cats, especially in patients being screened for cardiovascular disease. This prospective, partially blinded, randomized experimental study aimed to determine if sedation with alfaxalone would alter the appearance of the cardiac silhouette or pulmonary vasculature on thoracic radiographs or echocardiographic indices of cardiac or pulmonary vascular size. Eleven apparently healthy adult cats were recruited from a research colony. Four-view thoracic radiographs and an echocardiogram were performed at baseline and following a 5mg/kg intramuscular dose of alfaxalone. Vertebral heart score (VHS) and cranial and caudal lobar pulmonary vascular measurements were obtained at both time points by two independent blinded observers, and these were analyzed using two-way ANOVA. The nonblinded echocardiographer obtained echocardiographic measurements at both time points, which were analyzed using a paired t-test or Wilcoxon signed rank test. No significant differences were identified in VHS measurements or echocardiographic parameters between baseline and sedated cats. In healthy cats, alfaxalone does not appear to significantly affect the cardiovascular structures evaluated via thoracic radiography or echocardiography.

Significant age-related differences between lower leg muscles of older and younger female subjects detected by ultrashort echo time magnetization transfer modeling.

Magnetization transfer (MT) magnetic resonance imaging (MRI) can be used to estimate the fraction of water and macromolecular proton pools in tissues. MT modeling paired with ultrashort echo time acquisition (UTE-MT modeling) has been proposed to improve the evaluation of the myotendinous junction and fibrosis in muscle tissues, which the latter increases with aging. This study aimed to determine if the UTE-MT modeling technique is sensitive to age-related changes in the skeletal muscles of the lower leg. Institutional review board approval was obtained, and all recruited subjects provided written informed consent. The legs of 31 healthy younger (28.1±6.1years old, BMI = 22.3±3.5) and 20 older (74.7±5.5years old, BMI = 26.7±5.9) female subjects were imaged using UTE sequences on a 3T MRI scanner. MT ratio (MTR), macromolecular fraction (MMF), macromolecular T2 (T2-MM), and water T2 (T2-W) were calculated using UTE-MT modeling for the anterior tibialis (ATM), posterior tibialis (PTM), soleus (SM), and combined lateral muscles. Results were compared between groups using the Wilcoxon rank sum test. Three independent observers selected regions of interest (ROIs) and processed UTE-MRI images separately, and the intraclass correlation coefficient (ICC) was calculated for a reproducibility study. Significantly lower mean MTR and MMF values were present in the older compared with the younger group in all studied lower leg muscles. T2-MM showed significantly lower values in the older group only for PTM and SM muscles. In contrast, T2-W showed significantly higher values in the older group. The age-related differences were more pronounced for MMF (-17 to -19%) and T2-W (+20 to 47%) measurements in all muscle groups compared with other investigated MR measures. ICCs were higher than 0.93, indicating excellent consistency between the ROI selection and MRI measurements of independent readers. As demonstrated by significant differences between younger and older groups, this research emphasizes the potential of UTE-MT MRI techniques in evaluating age-related skeletal muscle changes.

Factors influencing the reliability of measurements in eyes with full-thickness macular holes: are we measuring incorrectly?

PurposeThe calliper function is used for manual measurements of full thickness macular holes (FTMHs). We aimed to investigate whether a reproducible difference could be detected beyond interobserver variability between two...