Tomography Scan Research Articles

Diagnostic Value of the Texture Analysis Parameters of Retroperitoneal Residual Masses on Computed Tomographic Scan after Chemotherapy in Non-Seminomatous Germ Cell Tumors.

After chemotherapy, patients with non-seminomatous germ cell tumors (NSGCTs) with residual masses >1 cm on computed tomography (CT) undergo surgery. However, in approximately 50% of cases, these masses only consist of necrosis/fibrosis. We aimed to develop a radiomics score to predict the malignant character of residual masses to avoid surgical overtreatment. Patients with NSGCTs who underwent surgery for residual masses between September 2007 and July 2020 were retrospectively identified from a unicenter database. Residual masses were delineated on post-chemotherapy contrast-enhanced CT scans. Tumor textures were obtained using the free software LifeX. We constructed a radiomics score using a penalized logistic regression model in a training dataset, and evaluated its performance on a test dataset. We included 76 patients, with 149 residual masses; 97 masses were malignant (65%). In the training dataset (n = 99 residual masses), the best model (ELASTIC-NET) led to a radiomics score based on eight texture features. In the test dataset, the area under the curve (AUC), sensibility, and specificity of this model were respectively estimated at 0.82 (95%CI, 0.69-0.95), 90.6% (75.0-98.0), and 61.1% (35.7-82.7). Our radiomics score may help in the prediction of the malignant nature of residual post-chemotherapy masses in NSGCTs before surgery, and thus limit overtreatment. However, these results are insufficient to simply select patients for surgery.

Attentional Ptycho-Tomography (APT) for three-dimensional nanoscale X-ray imaging with minimal data acquisition and computation time

Noninvasive X-ray imaging of nanoscale three-dimensional objects, such as integrated circuits (ICs), generally requires two types of scanning: ptychographic, which is translational and returns estimates of the complex electromagnetic field through the IC; combined with a tomographic scan, which collects these complex field projections from multiple angles. Here, we present Attentional Ptycho-Tomography (APT), an approach to drastically reduce the amount of angular scanning, and thus the total acquisition time. APT is machine learning-based, utilizing axial self-Attention for Ptycho-Tomographic reconstruction. APT is trained to obtain accurate reconstructions of the ICs, despite the incompleteness of the measurements. The training process includes regularizing priors in the form of typical patterns found in IC interiors, and the physics of X-ray propagation through the IC. We show that APT with ×12 reduced angles achieves fidelity comparable to the gold standard Simultaneous Algebraic Reconstruction Technique (SART) with the original set of angles. When using the same set of reduced angles, then APT also outperforms Filtered Back Projection (FBP), Simultaneous Iterative Reconstruction Technique (SIRT) and SART. The time needed to compute the reconstruction is also reduced, because the trained neural network is a forward operation, unlike the iterative nature of these alternatives. Our experiments show that, without loss in quality, for a 4.48 × 93.2 × 3.92 µm3 IC (≃6 × 108 voxels), APT reduces the total data acquisition and computation time from 67.96 h to 38 min. We expect our physics-assisted and attention-utilizing machine learning framework to be applicable to other branches of nanoscale imaging, including materials science and biological imaging.

A comparison of the sarcopenic effect of androgen receptor-axis-targeted agents vs. androgen deprivation alone in patients with metastatic prostate cancer.

Androgen deprivation therapy (ADT) with androgen receptor axis-targeted (ARAT) therapy is the standard of care provided to patients with metastatic prostate cancer. While effective, it results in sequelae, such as loss of skeletal muscle mass. In this study, we compared the sarcopenic effects of abiraterone and enzalutamide, two ARATs used to treat metastatic prostate cancer. Our cohort was comprised of 55 patients diagnosed with metastatic hormonenaive prostate cancer from 2014-2019. Patients were divided into three treatment groups: gonadotropin-releasing hormone (GnRH ) agonist alone; GnRH agonist combined with abiraterone acetate; and GnRH agonist combined with enzalutamide. We then compared axial computed tomographic (CT) scans at the L3 level before and after the initiation of hormone therapy for each patient. A skeletal muscle index (SMI) was calculated for each patient, and alongside clinical data, was compared between the three groups. One-way analysis of variance (ANOVA) and Fisher's exact test were used to compare means and proportions, respectively. Baseline clinical characteristics were not significantly different between the three groups. The percent SMI change and number of newly sarcopenic patients were not found to be significantly different between the groups. The only variable that was significantly different across the three groups was time between CT scans. Although we found no significant difference in the sarcopenic effects of GnRH alone, GnRH with abiraterone, or GnRH with enzalutamide in our cohort of 55 hormone-naive metastatic prostate cancer patients, overall decreases in muscle mass were observed for all three groups. This highlights the importance of muscle-retaining strategies for patients undergoing ADT for metastatic prostate cancer, regardless of therapeutic regimen.

Enhanced recovery after surgery pathway with modified biportal endoscopic transforaminal lumbar interbody fusion using a large cage. Comparative study with minimally invasive microscopic transforaminal lumbar interbody fusion.

Studies about the clinical efficacy of endoscopic lumbar interbody fusion using an enhanced recovery after surgery (ERAS) pathway are insufficient. Thus, the purpose of this study was to investigate clinical usefulness of biportal endoscopic transforaminal lumbar interbody fusion (TLIF) using an ERAS compared with microscopic TLIF. Prospectively collected data were retrospectively analyzed. Patients who received modified biportal endoscopic TLIF with ERAS were grouped into an endoscopic TLIF group. Those who received microscopic TLIF without ERAS were grouped into a microscopic TLIF group. Clinical and radiologic parameters were compared between two groups. Fusion rate was evaluated using sagittal reconstruction images of postoperative computed tomographic (CT) scan. There were 32 patients in the endoscopic TLIF group with ERAS and 41 patients in the microscopic TLIF group without ERAS. Visual analog scale (VAS) scores for back pain preoperatively at day one and day two were significantly (p < 0.05) higher in the non-ERAS microscopic TLIF group than in the ERAS endoscopic TLIF group. Preoperative Oswestry Disability Index were significantly improved at the last follow-up in both groups. The fusion rate at postoperative one year was 87.5% in the endoscopic TLIF group and 85.4% in the microscopic TLIF group. Biportal endoscopic TLIF with ERAS pathway may have good aspect to accelerate recovery after surgery. There was no inferiority of fusion rate of endoscopic TLIF comparing to microscopic TLIF. Biportal endoscopic TLIF using a large cage with ERAS pathway may be a good alternative treatment for lumbar degenerative disease.

LASER-ULTRASOUND DIAGNOSTICS OF PLASTIC PRODUCTS MANUFACTURED BY LASER STEREOLITHOGRAPHY

Abstract. This paper discusses the application of methods of non-destructive testing and flaw detection of plastic products manufactured by additive technologies. The modern development of additive technologies associated with the active transition from the manufacture of prototypes and test samples to the manufacture of functional products increases the requirements for improving the quality of manufacturing and conducting non-destructive diagnostics of finished products, including plastic materials. The overall productivity of the production process can be increased by increasing the yield due to a decrease in the number of defects, which is ensured by process control and the quality of finished products. The method of laser-ultrasound diagnostics allows monitoring and flaw detection of products made of different materials with good spatial resolution, which is not always possible, for example, by tomographic scanning. Thus, the main purpose of this work is to evaluate the possibility of using laser-ultrasonic methods to detect potential defects and to track the impact of the additive manufacturing process on the quality of plastic products.

Comparison of Morphometric Outcomes following Open Posterior Expansion versus Endoscopic Strip Craniectomy for Sagittal Synostosis.

Open middle and posterior cranial vault expansion (OPVE) or endoscopic (ES) strip craniectomy are two surgical techniques for normalization of head shape in isolated sagittal synostosis. This study aims to compare 2-year cranial morphometrics after these two approaches. The authors performed morphometric analysis on preoperative [time (T) 0], immediately postoperative (T1), and 2-year (T2) postoperative computed tomographic scans of patients who underwent OPVE or ES before 4 months of age. Perioperative data and morphometrics were compared between the two groups and age-matched controls. Nineteen patients were included in the ES cohort, 19 age-matched patients were included in the OPVE cohort, and 57 were included as controls. Median surgery time and blood transfusion volume were less for the ES approach (118 minutes and 0 cc, respectively) compared with OPVE (204 minutes and 250 cc, respectively). Anthropometric measurements after OPVE were closer in normal controls at T1 compared with ES, but the skull shapes were comparable at T2. In the midsagittal plane, anterior vault was higher after OPVE at T2 compared with both ES and controls, but the posterior length was shorter and closer to controls than in the ES cohort. Cranial volumes were like controls for both cohorts at T2. There was no difference in complication rate. Both OPVE and ES techniques result in normalization of cranial shape in patients with isolated sagittal synostosis after 2 years with minimal morphometric differences. Family decision-making between the two approaches should be based on age at presentation, avoidance of blood transfusion, scar pattern, and availability of helmet molding and not on expected outcome. Therapeutic, III.

Case Report: Challenging diagnostic of an accessory spleen mimicking a retroperitoneal tumor: A case report and review of the literature

Background: The accessory spleen is a congenital defect with an additional splenic tissue to the native spleen due to an incomplete fusion of splenic masses during the embryologic period. The preoperative diagnosis is usually mistaken for a retroperitoneal neoplasm. The aim of the present manuscript is to highlight the diagnostic difficulties of a retroperitoneal spleen. Case presentation: A 41-year-old woman was admitted to the surgical department of Habib Thameur Hospital, Tunis, for an abdominal mass discovered by auto palpation associated with a left lower quadrant pain. The computed tomographic scan showed a heterogeneous and partially necrotic retroperitoneal mass located along the left primitive iliac vessels. Arterial supply to the mass arose from the aorta and the left iliac vessel. The spleen was normal. MRI examination showed a left retroperitoneal heterogeneous and necrotic mass, surrounding the iliac vessels extended from the aortic to the left iliac bifurcation, hyper vascularized at the arterial time with a peripheral capsule intensely enhanced, and there were two other lateroaortic vascularized masses. The patient had a laparotomy resection of the retroperitoneal mass. The result of the specimen examination was an accessory spleen. The postoperative outcome was uneventful. Conclusion: An accessory spleen on the retroperitoneal position is extremely uncommon. Preoperative diagnosis is still challenging. The main misdiagnosis was neoplastic disease.

Latent Coronary Plaque Morphology From Computed Tomography Angiography, Molecular Disease Activity on Positron Emission Tomography, and Clinical Outcomes.

Assessments of coronary disease activity with 18F-sodium fluoride positron emission tomography and radiomics-based precision coronary plaque phenotyping derived from coronary computed tomography angiography may enhance risk stratification in patients with coronary artery disease. We sought to investigate whether the prognostic information provided by these 2 approaches is complementary in the prediction of myocardial infarction. Patients with known coronary artery disease underwent coronary 18F-sodium fluoride positron emission tomography and coronary computed tomography angiography on a hybrid positron emission tomography/computed tomography scanner. Coronary 18F-NaF uptake was determined by the coronary microcalcification activity. We performed quantitative plaque analysis of coronary computed tomography angiography datasets and extracted 1103 radiomic features for each plaque. Using weighted correlation network analysis, we derived latent morphological features of coronary lesions which were aggregated to patient-level radiomics nomograms to predict myocardial infarction. Among 260 patients with established coronary artery disease (age, 65±9 years; 83% men), 179 (69%) participants showed increased coronary 18F-NaF activity (coronary microcalcification activity>0). Over 53 (40-59) months of follow-up, 18 patients had a myocardial infarction. Using weighted correlation network analysis, we derived 15 distinct eigen radiomic features representing latent morphological coronary plaque patterns in an unsupervised fashion. Following adjustments for calcified, noncalcified, and low-density noncalcified plaque volumes and 18F-NaF coronary microcalcification activity, 4 radiomic features remained independent predictors of myocardial infarction (hazard ratio, 1.46 [95% CI, 1.03-2.08]; P=0.03; hazard ratio, 1.62 [95% CI, 1.04-2.54]; P=0.02; hazard ratio, 1.49 [95% CI, 1.07-2.06]; P=0.01; and hazard ratio, 1.50 (95% CI, 1.05-2.13); P=0.02). In patients with established coronary artery disease, latent coronary plaque morphological features, quantitative plaque volumes, and disease activity on 18F-sodium fluoride positron emission tomography are additive predictors of myocardial infarction.

Bare Stent Fracture After TEVAR With the Modified Restrictive Bare Stent (RBS) Technique in Type B Aortic Dissections.

The aim was to assess the mid-term aortic remodeling and bare-metal stent (BMS) integrity of the restricted bare stent (RBS) technique reconstruction in aortic dissections. This retrospective cohort study included prospectively collected patients treated with the modified RBS technique between 2017 and 2020. The preoperative, postoperative, and last follow-up computed tomographic (CT) scans were analyzed in the centerline at the mid-descending, celiac trunk (CeT), and the mid-abdominal levels for false lumen (FL) patency, aortic diameter, and true lumen (TL) diameter changes. Bare-metal stent integrity was assessed in the 3-dimensional multiplanar reformats. The median follow-up of the cohort (n=17) was 26 (11, 45) months. The procedure was mainly performed with the Relay NBS endograft (15/17; 88%) + E-XL BMS (17/17; 100%). Postoperative mortality, paraplegia, stroke, renovisceral vessel loss, and type I and III endoleaks were not observed. BMS fractured in 6 patients (6/17; 36%), damaged the dissection flap in 4/17 (24%), and led to the reperfusion of the FL and re-interventions with TEVAR (4/17; 24%). Two patients without FL reperfusion showed stable CT follow-ups 13 and 17 months after the fracture diagnosis. The TL expansion was seen at all landmarks and peaked in the thoracic aorta (+10; 6, 15; p<0.001). The FL thrombosis after modified RBS was only relevant in the thoracic aorta (p<0.001) and at CeT (p=0.003). The aortic diameter was stable in the thoracic aorta and increased at distal landmarks (CeT [+5; 1, 10; p=0.001]; mid-abdominal [+3; 1, 5; p=0.004]). The modified RBS technique could not stop aortic growth below the diaphragm and prevent new membrane rupture due to the fractures of the BMS and consecutive flap damage with the reperfusion of the FL. The treatment of complicated type B aortic dissections with TEVAR has become a standard. Particularly, patients with true lumen collapse and malperfusion may benefit from a more aggressive treatment strategy including proximal TEVAR and distal bare-metal stent implantation to re-open the true lumen and to prevent distal stent-induced new entry. However, this study reports the challenges of this approach with a high rate of bare-metal stent fractures during the follow-up. The fractures that occurred at the site of vertical nitinol bridges led to the dissection membrane ruptures and the reperfusion of the false lumen with consecutive dilatation. A close follow-up is mandatory to detect this complication and to treat the patients with TEVAR extension.

A Novel Trajectory of C7 Laminar Screws Determined Using Three-Dimensional Computed Tomography and Surgical Simulation Software: Comparison with a Pre-existing Trajectory.

Examination using three-dimensional screw trajectory software and computed tomographic scans. To evaluate the feasibility of a novel trajectory for C7 laminar screws and to compare it with an old trajectory. The previously reported trajectory of C7 laminar screws has a horizontal direction without a fixed target point. Our new trajectory has a cephalad direction with a fixed target point. Computed tomographic scans of a total of 50 male and 50 female patients were utilized. The placement of C7 laminar screws was activated employing the new and old trajectories. The success rate, the causes of failure, and the maximum allowable length of each trajectory were compared. Employing the new trajectory, the success rates of the unilaminar and bilaminar screws were 93% and 83%, respectively, which were significantly better than the old trajectory (80%, p<0.0001 and 70%, p=0.0003). The most prevalent cause of failure was laminar cortical breach followed by facet joint violation. The new trajectory also offered significantly longer maximum allowable screw length in unilaminar (32.5±4.3 mm vs. 26.5±2.6 mm, p<0.001), bilaminar cephalic (29.5±3.8 mm vs. 25.9±2.6 mm, p<0.0001) and bilaminar caudal (33.1±2.6 mm vs. 25.8±3.1 mm, p<0.001) screws than the old trajectory. With the new and old trajectories, 70% vs. 6% of unilaminar, 60% vs. 2% of bilaminar caudal, and 32% vs. 4% of bilaminar cephalic screws could be protracted perfectly into the corresponding lateral mass without any laminar cortical or facet joint violation (p<0.0001). The novel trajectory possesses a substantially higher success rate, longer maximum allowable screw length, and higher chance to be extended into the lateral mass (a condition known as a lamino-lateral mass screw) than the old trajectory.

Tillaux Fracture Associated with Adult Ankle Fracture Injury.

Tillaux fractures in adults are rare and, if unrecognized, can lead to ankle fracture healing complications, early progression of arthritis, and limited ankle movement caused by pain and degenerative changes. The Tillaux fracture was first described by Paul Tillaux as an external rotation injury of the ankle, involving an avulsion fracture of the distal anterolateral tibia. This fracture can be easily overlooked on plain radiographs in the adult. A high index of suspicion for this type of fracture pattern along with the use of computed tomographic scanning can help confirm the suspected diagnosis, rule out other tibial injuries, and provide more information on the best course of action. Historically, Tillaux fractures have been more common in adolescents because of the open tibial epiphyseal plate. Once the epiphyseal plate fully closes, skeletal maturity is achieved, thus making it extremely unusual for the anterior tibiofibular ligament to cause an avulsion fragment of the distal anterolateral tibia. Because of how uncommon this type of fracture is in adults, it has rarely been reported in our literature. We reviewed the literature and present a case report of this rare fracture injury.

Evaluating the Performance of the IMPACT Model in the Prehospital TXA for TBI Trial (P14-7.001)

<h3>Objective:</h3> To test the IMPACT model’s performance in a contemporary clinical trial population. <h3>Background:</h3> The International Mission on Prognosis and Analysis of Clinical Trials in Traumatic Brain Injury (IMPACT) prognostic model predicts functional outcome after moderate-severe traumatic brain injury (TBI). Our previous work suggested that glial fibrillary acidic protein (GFAP) may improve the discrimination of outcome when added to prognostic models. <h3>Design/Methods:</h3> We analyzed data from a subset subjects from the phase II double-blind, multicenter randomized controlled trial, “Prehospital Tranexamic Acid Use for Traumatic Brain Injury.” This subset was limited to subjects in the placebo arm of the parent trial with evidence of hemorrhage on initial head computed tomographic (CT) scan. All 3 versions (core, extended, lab) of the IMPACT model were evaluated against 6-month mortality, plus an exploratory 4^th version (lab+GFAP). We compared our results to previously published validation results from the CENTER-TBI cohort. <h3>Results:</h3> Within the subset (n=166), 127 subjects had complete 6-month outcome data. Predictor variables were missing &lt;10% (0–9.4%) of cases, and were imputed (GCS motor score, pupillary reactivity, serum glucose, serum hemoglobin, hypoxia, and Marshall CT score). GFAP was associated with mortality (p=0.004). The core model discriminated poorly in the subset (AUC 0.60 [95% CI: 0.48–0.71], p=0.096). The extended model discriminated well (AUC 0.73 [95% CI: 0.64–0.82], p&lt;0.001). The lab model discriminated non-significantly better (AUC 0.76 [95% CI: 0.66–0.86], p=0.167). Adding GFAP to the lab model improved discrimination further (AUC 0.83 [95% CI: 0.76–0.90], p=0.004). All 4 models overestimated mortality compared with the observed rate (n=31, 24% v. 26–82%). <h3>Conclusions:</h3> In comparison with the observational CENTER-TBI validation cohort, the IMPACT models (core/extended/lab) discriminated mortality less well in a subset of the TXA trial. The addition of GFAP improved discrimination for mortality, but further work is needed to optimize its addition to the lab model. <b>Disclosure:</b> Dr. Hinson has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Biogen. Dr. Hinson has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for UCSF. Dr. Hinson has received personal compensation in the range of $10,000-$49,999 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for American Heart Association. Shannon McWeeney has nothing to disclose. Adam Ferguson has received personal compensation in the range of $500-$4,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Spine X Inc. Adam Ferguson has received personal compensation in the range of $5,000-$9,999 for serving on a Scientific Advisory or Data Safety Monitoring board for Neuronasal Inc.. The institution of Adam Ferguson has received research support from NIH/NINDS. The institution of Adam Ferguson has received research support from VA RR&amp;D. The institution of Adam Ferguson has received research support from VA BLR&amp;D. The institution of Adam Ferguson has received research support from Wings for Life Foundation/Craig H Neilsen Foundation. The institution of Adam Ferguson has received research support from Wings for Life Foundation. The institution of Adam Ferguson has received research support from DoD/CDMRP. The institution of Adam Ferguson has received research support from DARPA. The institution of Adam Ferguson has received research support from DoE. Adam Ferguson has received personal compensation in the range of $500-$4,999 for serving as a Reviewer with NIH/CSR. Dr. Schreiber has received personal compensation in the range of $5,000-$9,999 for serving as a Consultant for CSL Behring. Dr. Schreiber has received personal compensation in the range of $10,000-$49,999 for serving as a Consultant for Harmonetics. Dr. Schreiber has received personal compensation in the range of $500-$4,999 for serving as a Consultant for Tricol. Dr. Schreiber has received personal compensation in the range of $0-$499 for serving as an Editor, Associate Editor, or Editorial Advisory Board Member for Trauma Textbook. Dr. Schreiber has received personal compensation in the range of $10,000-$49,999 for serving as an Expert Witness for Lawyers. The institution of Dr. Schreiber has received research support from DoD. Dr. Rowell has nothing to disclose.

Impact of One-Piece Fronto-Orbital Distraction Osteogenesis on Orbital Morphology and Strabismus Development in Unilateral Craniosynostosis.

Unicoronal craniosynostosis (UCS) is associated with orbital dysmorphologies that underlie ophthalmologic dysfunctions, such as strabismus. This study aimed to assess orbital dysmorphology in patients with UCS and how it changes after fronto-orbital distraction osteogenesis (FODO), and to analyze the features of new-onset strabismus. A retrospective analysis was conducted on 19 patients with UCS who underwent FODO between May of 2008 and November of 2020. Ophthalmologic records and computed tomographic scans were reviewed. Seven parameters, including width, height, volume, and four-direction orbital angles were evaluated in patients with UCS and compared with those of age-matched control subjects. The superolateral angle and vertical angle of the ipsilateral orbit and the superomedial angle (SMA) of the contralateral orbit were more obtuse than those of the controls. Following FODO, the ipsilateral superolateral angle was decreased from 69.2 ± 5.4 degrees to 59.1 ± 4.2 degrees ( P = 0.001), and the contralateral SMA was decreased from 64.8 ± 5.8 degrees to 60.2 ± 6.0 degrees ( P = 0.003). Four of the 17 patients without strabismus in the preoperative period developed strabismus, and the horizontal type was the most common. Logistic regression analysis demonstrated a significant association between new-onset strabismus and SMA difference between both orbits (OR, 1.39; P = 0.041). Orbital dysmorphology in the UCS is bilateral, and the orbital roofs are dysmorphic. The bilateral orbital roofs are lifted toward the fused coronal suture and can be improved after FODO. Horizontal strabismus, such as esotropia and exotropia, is common after FODO, and superomedial orbital roof asymmetry may play a role in its development. Therapeutic, IV.

Repeatability of Scheimpflug based corneal tomography parameters in advanced keratoconus with thin corneas.

To determine the repeatability limits of corneal tomography parameters in patients with advanced and moderately thin keratoconic corneas to assist in planning thickness-based procedural interventions. Prospective, single-centre, repeatability study. Three tomography scans using the Pentacam AXL were obtained from patients with keratoconus with thinnest corneal thickness (TCT) ≦400 µm (sub-400 group) and compared to those with TCT = 450-500 µm (450-plus group). Eyes with previous crosslinking, intraocular surgery, or acute corneal hydrops were excluded. Eyes were age and gender-matched. The within-subject standard deviations for flat keratometry (K1), steep keratometry (K2), maximal keratometry (Kmax), astigmatism and TCT were used to calculate respective repeatability limits (r). Intra-class correlation coefficients (ICC) were also analysed. The sub-400 group comprised 114 eyes from 114 participants, and the 450-plus group comprised 114 eyes from 114 participants. In the sub-400 group, TCT was amongst the least repeatable parameters (33.92 µm; ICC 0.96), compared with the 450-plus group (14.32 µm; ICC 0.99, p < 0.01). In the sub-400 group, K1 and K2 of the anterior surface were the most repeatable parameters (r 3.79 and 3.22 respectively; ICC 0.97 and 0.98 respectively) compared with the 450-plus group (r 1.17 and 0.92 respectively; and ICC 0.98 and 0.99 respectively, p < 0.01). The repeatability of corneal tomography measurements is significantly reduced in sub-400 keratoconic corneas when compared to 450-plus corneas. Repeatability limits should be carefully considered when surgical interventions are planned for such patients.

Spatial complexity of burrow attributes and their impact on porosity and permeability distributions in bioturbated reservoirs

Bioturbated carbonate rocks can form high-quality aquifers and reservoirs. Although the controls on the porosity and permeability of these rocks are fairly understood at the well-bore scale, how such characteristics vary spatially across various scales of observation is still a major unsolved problem. This study integrates results of outcrop observations, imaging with scanning electron microscopy (SEM), computer tomographic (CT) scanning, petrographic analysis, and petrophysical measurements to understand how burrow intensity and burrowing style control the spatial variability of porosity and permeability of one stratum accumulated in a carbonate ramp. The CT scan data revealed two burrowing styles, pipe framework (in the upper part of the stratum, surface constrained textural heterogeneity) and bio-retexturing (in the lower part of the stratum, non-surface-constrained textural heterogeneity). The studied stratum is dominated by the micropores (cross-section>10 μm) of the host rock matrix (HRM), which comprise >50 % of the total porosity within the stratum. Porosity in the stratum does not vary substantially in vertical or lateral trends. In contrast, and perhaps most importantly, permeability does vary vertically and laterally depending on the scale of measurement, burrow percentage, and burrowing style. These results suggested that the storage capacity of the studied stratum is independent of bioturbation, whereas the flow capacity is strongly dependent on bioturbation. There is a substantial vertical change in permeability in the stratum in comparison to only small changes in the lateral direction across the layer of interest. The data also suggested that the subtle lateral change in permeability is controlled by bio-retexturing, which resulted in the homogenization of grain-dominated and mud-dominated sediments by bioturbation. Such a process can be destructive for the permeability compared to the pipe-connected burrowing style. We clearly show that the ichnologically-controlled porosity and permeability trends of the studied stratum are relevant at the field scale. Understanding such trends in the context of paleoenvironmental conditions provides insight into the fluid flow quality of bioturbated carbonates, which constitute a large proportion of water aquifers and hydrocarbon reservoirs globally.

Anterior provisional fixed partial dentures: A finite element analysis.

The aim of this study was to analyze the stress distribution of fiber-reinforced composite provisional fixed partial denture utilizing a finite element analysis model. Three anterior teeth were collected: upper right central, left central, and right lateral incisors. A fiber-reinforced composite strip was applied to the palatal surfaces of the teeth. Micro-computed tomographic scans were acquired of the models in order to generate three-dimensional geometrical replicas. Finite element analysis was used to assess the stress distribution of fiber-reinforced composite provisional fixed partial denture using different pontic types under static applied forces that were 100, 30, and 0N. The maximum stress values were found on the unprepared natural pontic. Stress values ranged from 92.2 to 909.8, 116.4 to 646.7, and 93.8 to 393.5MPa for composite, naturally prepared, and natural unprepared pontic, respectively. Using unprepared natural tooth pontic in anterior provisional fixed partial denture to replace missing central incisors is considered superior to other types in terms of stress distribution.

Extended law of laplace for measurement of the cloverleaf anatomy of the aortic root

The cross-sectional shape of the aortic root is cloverleaf, not circular, raising controversy regarding how best to measure its radiographic “diameter” for aortic event prediction. We mathematically extended the law of Laplace to estimate aortic wall stress within this cloverleaf region, simultaneously identifying a new metric of aortic root dimension that can be applied to clinical measurement of the aortic root and sinuses of Valsalva on clinical computerized tomographic scans. Enforcing equilibrium between blood pressure and wall stress, finite element computations were performed to evaluate the mathematical derivation. The resulting Laplace diameter was compared with existing methods of aortic root measurement across four patient groups: non-syndromic aneurysm, bicuspid aortic valve, Marfan syndrome, and non-dilated root patients (total 106 patients, 62 M, 44 F). (1) Wall stress: Mean wall stress at the depth of the sinuses followed this equation: Wall stress = BP × Circumscribing circle diameter/(2 × Aortic wall thickness). Therefore, the diameter of the circle enclosing the root cloverleaf, that is, twice the distance between the center, where the sinus-to-commissure lines coincide, and the depth of the sinuses, may replace diameter in the Laplace relation for a cloverleaf cross-section (or any shaped cross-section with two or more planes of symmetry). This mathematically derived result was verified by computational finite element analyses. (2) Diameters: CT scan measurements showed a significant difference between this new metric, the Laplace diameter, and the sinus-to-commissure, mid-sinus-to-mid-sinus, and coronal measurements in all four groups (p-value < 0.05). The average Laplace diameter measurements differed significantly from the other measurements in all patient groups. Among the various possible measurements within the aortic root, the diameter of the circumscribing circle, enclosing the cloverleaf, represents the diameter most closely related to wall stress. This diameter is larger than the other measurements, indicating an underestimation of wall stress by prior measurements, and otherwise provides an unbiased, convenient, consistent, physics-based measurement for clinical use.Graphical abstract“Diameter” applies to circles. Our mathematical derivation of an extension of the law of Laplace, from circular to cloverleaf cross-sectional geometries of the aortic root, has implications for measurement of aortic root “diameter.” The suggested method is as follows: (1) the “center” of the aortic root is identified by drawing three sinus-to-commissure lines. The intersection of these three lines identifies the “center” of the cloverleaf. (2) The largest radius from this center point to any of the sinuses is identified as the “radius” of the aortic root. (3) This radius is doubled to give the “diameter” of the aortic root. We find that this diameter best corresponds to maximal wall stress in the aortic root. Please note that this diameter defines the smallest circle that completely encloses the cloverleaf shape, touching the depths of all three sinuses.

Prognostic value of pre-infusion tumor growth rate for patients with lymphoma receiving chimeric antigen receptor T-cell therapy

Background aimsChimeric antigen receptor T-cell therapy (CART) prolongs survival for patients with refractory or relapsed lymphoma, yet its efficacy is affected by the tumor burden. The relevance of tumor kinetics before infusion is unknown. We aimed to study the prognostic value of the pre-infusion tumor growth rate (TGRpre-BL) for progression-free (PFS) and overall survival (OS). MethodsConsecutive patients with available pre-baseline (pre-BL) and baseline (BL) computed tomography or positron emission tomography/computed tomography scan before CART were included. TGR was determined as change of Lugano criteria-based tumor burden between pre-BL, BL and follow-up examinations (FU) in relation to days between imaging exams. Overall response rate (ORR), depth or response (DoR) and PFS were determined based on Lugano criteria. Multivariate regression analysis studied association of TGR with ORR and DoR. Proportional Cox regression analysis studied association of TGR with PFS and OS. ResultsIn total, 62 patients met the inclusion criteria. The median TGRpre-BL was 7.5 mm2/d (interquartile range –14.6 mm2/d to 48.7 mm2/d); TGRpre-BL was positive (TGRpre-BL POS) in 58% of patients and negative (TGRpre-BL NEG, indicating tumor shrinkage) in 42% of patients. Patients who were TGRpre-BL POS had a 90-day (FU2) ORR of 62%, a DoR of –86% and a median PFS of 124 days. Patients who were TGRpre-BL NEG had a 90-day ORR of 44%, DoR of –47% and a median PFS of 105 days. ORR and DoR were not associated with slower TGR (P = 0.751, P = 0.198). Patients with an increase of TGR from pre-BL over BL to 30-day FU (FU1) ≥100% (TGRpre-BL-to-FU1≥100%) showed a significant association with shorter median PFS (31 days versus 343 days, P = 0.002) and shorter median OS after CART (93 days versus not reached, P < 0.001), compared with patients with TGRpre-BL-to-FU1<100%. ConclusionsIn the context of CART, differences in pre-infusion tumor kinetics showed minor differences in ORR, DoR, PFS and OS, whereas the change of the TGR from pre-BL to 30-day FU significantly stratified PFS and OS. In this patient population of refractory or relapsed lymphomas, TGR is readily available based on pre-BL imaging, and its change throughout CART should be explored as a potential novel imaging biomarker of early response.

SMALL MAGNESIUM CYLINDERS SIGNIFICANTLY INCREASE BONE VOLUME AND TRABECULAR THICKNESS WITH CONSTANT DENSITY AFTER IMPLANTATION IN THE SUBCHONDRAL BONE PLATE IN OSTEOARTHRITIC RABBITS: A PILOT STUDY

There is no optimal therapy to stop or cure chondral degeneration in osteoarthritis (OA). Beside cartilage, subchondral bone is involved. The often sclerotic bone is mechanically less solid which in turn influences negatively chondral quality. Microfracturing as therapeutic technique aims to enhance bone quality but is applied only in smaller cartilage lesions. The osteoproliferative properties of Magnesium (Mg) have been shown repeatedly1-3. The present study examined the influence of micro-scaled Mg cylinders compared to sole drilling in an OA model.Ten New Zealand White rabbits underwent anterior crucial ligament transection. During 12 weeks after surgery, the animals developed OA as previously described4. In a second surgery, half of the animals received 20 drill holes (ø 0.5mm) and the other half received 20 drill holes, which were additionally filled with one Mg cylinder each. Extracapsular plication was performed in all animals. During the follow-up of 8 weeks three µ-computed tomographic (µCT) scans were performed: immediately after surgery and after four and eight weeks. Changes of bone volume, trabecular thickness and bone density were calculated and compared.µCT evaluation showed an increase in bone volume and trabecular thickness in both groups. This increase was significantly higher in rabbits which received Mg cylinders showing thrice as high values for both parameters (bone volume: Mg group +44.5%, drilling group +15.1%, p≤0.025; trabecular thickness: Mg group +53.2%, drilling group +16.9%, p≤0.025). Also bone density increased in both groups, but on a distinctly lower level and with no significant difference.Although profound higher bone volume was found after implantation of Mg cylinders, µCT showed similar levels of bone density indicating adequate bone quality in this OA model. Macroscopic and histological evaluation of cartilage condition have to reveal possible impact on OA progression. Additionally, current examination implement different alloys and influence on lameness.

A prospective cohort study on active surveillance after neoadjuvant chemoradiotherapy for esophageal cancer: protocol of Surgery As Needed for Oesophageal cancer-2

BackgroundNeoadjuvant chemoradiotherapy (nCRT) followed by esophagectomy is a standard treatment for potentially curable esophageal cancer. Active surveillance in patients with a clinically complete response (cCR) 12 weeks after nCRT is regarded as possible alternative to standard surgery. The aim of this study is to monitor the safety, adherence and effectiveness of active surveillance in patients outside a randomized trial.MethodsThis nationwide prospective cohort study aims to accrue operable patients with non-metastatic histologically proven adenocarcinoma or squamous cell carcinoma of the esophagus or esophagogastric junction. Patients receive nCRT and response evaluation consists of upper endoscopy with bite-on-bite biopsies, endoscopic ultrasonography plus fine-needle aspiration of suspicious lymph nodes and 18F-fluorodeoxyglucose positron emission tomography/computed tomography scan. When residue or regrowth of tumor in the absence of distant metastases is detected, surgical resection is advised. Patients with cCR after nCRT are suitable to undergo active surveillance. Patients can consult an independent physician or psychologist to support decision-making. Primary endpoint is the number and severity of adverse events in patients with cCR undergoing active surveillance, defined as complications from response evaluations, delayed surgery and the development of distant metastases. Secondary endpoints include timing and quality of diagnostic modalities, overall survival, progression-free survival, fear of cancer recurrence and decisional regret.DiscussionActive surveillance after nCRT may be an alternative to standard surgery in patients with esophageal cancer. Similar to organ-sparing approaches applied in other cancer types, the safety and efficacy of active surveillance needs monitoring before data from randomized trials are available.Trial registrationThe SANO-2 study has been registered at ClinicalTrials.gov as NCT04886635 (May 14, 2021) – Retrospectively registered.