Computed Tomography Measurements Research Articles

The potential of computed tomography in odontometry: application to a Mesolithic dog

A large odontometric reference database is essential for a clear and reliable differentiation between the teeth of dogs and wolves found in archaeological contexts. However, the data compilation of skeletal material is a slow process because access to dog remains may be difficult. The expansion of a dental database could benefit from computed tomography (CT) scans performed on live dogs during medical appointments and archived in veterinary clinics. To enable it, however, the reliability and accuracy of digital measurements must first be validated. This is the main objective of this paper.We tested the accuracy of dental measurements obtained from CT scans of deceased modern dogs and one Mesolithic dog. CT measurements were obtained using multi-planar reconstruction (MPR) (bi-dimensional images) and three-dimensional volume rendering (3D VR), either using bone or soft tissue windows. Then, measurements were compared with data obtained with a conventional caliper (Fischer Darex®, France). The sample comprised 25 maxillary fourth premolars and 17 maxillary canines. Measurements included the mesiodistal length (MDL) and the vestibular palatine width (VPW). Intra- and inter-observer variations were assessed by calculating the technical error of measurement (TEM). This approach was also used to assess the level of agreement between both techniques, complemented by a Bland-Altman analysis.Intra-observer (TEM = 0.52% to 5.98%) and inter-observer variations (TEM = 3.15% to 7.14%) were relatively small for most standard measurements, windows, and CT approaches. In the case of the MPR approach, the soft tissue window provided less observer variation on the fourth premolar; the same occurred for the bone window regarding the canine. The soft tissue window generally provided less observer variation with the VR approach. CT and caliper agreement ranged from 2.89% to 7.31% (MPR), and from 2.92% to 9.42% (3D VR). At least 91% of the CT measurements were within the Bland-Altman 95% confidence interval. We were able to carry out a thorough odontometric study of the Muge dog skull – a specimen dated to the Mesolithic period, using the MPR approach (with both bone and soft tissue windows).Both the MPR and VR CT scan approaches were validated, thus confirming digital data as an alternative way to generate more comprehensive odontometric references.

Association of computed tomography scores to psychophysical measures of olfaction: A systematic review and meta-analysis.

While various sinus computed tomography (CT) scoring systems have been proposed and used in the literature, no single system has been identified as superior. The strength of associations between CT scoring systems and measures of olfaction also remains unclear. A systematic review of PubMed, CINAHL, Scopus, and the Cochrane Library was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Studies that reported both CT scores and measures of olfaction in a cross-sectional manner were included. A total of 37 studies were eligible for meta-analysis. Of 8035 patients with chronic rhinosinusitis, 55.6% were male patients and 53.2% had chronic rhinosinusitis with nasal polyps. Analysis by meta-regression was performed of Lund-Mackay (LM) versus Smell Identification Test-40 (SIT-40; 12 studies), Brief Smell Identification Test (BSIT; 10 studies), Sniffin' Sticks (SS; 10 studies), and Toyota & Takagi (T&T) olfactometry (four studies). A significant moderate association was found between LM and SIT-40 (R2 =0.612, p<0.001) and LM and SS (R2 =0.612, p<0.001). An association between LM and BSIT approached significance (R2 =0.461, p=0.054). No significant associations were noted between LM and T&T olfactometry and between LM and SS when stratified by nasal polyp status. There is a significant moderate association of current CT scoring systems to SIT-40 and SS. Further research should focus on associations of objective measures of olfaction to CT scores of the nasal cavity, sinuses, and olfactory cleft, as well as other disease markers.

Cross-sectional computed tomography assessment of exophthalmos in comparison to clinical measurement via Hertel exophthalmometry

To determine protrusion assessment via Hertel exophthalmometry in comparison to measurement on Computed Tomography (CT). Retrospective blinded comparison of exophthalmos measurements on axial CT with Hertel exophthalmometry measurements in 113 patients. Descriptive statistics, Pearson’s correlation, Kruskal–Wallis and Mann–Whitney-U test were employed for analysis. Mean difference of proptosis between both eyes was 2.4 (SD ± 2.0) mm in CT and 2.2 (SD ± 2.0) mm in Hertel measurements. Proptosis of 0–2 mm was present in 69 (61.1%), and > 2 mm in 42 (38.9%) patients in Hertel measurements (CT 64 (56.6%), and 49 (43.4%) patients). Pearson’s coefficient showed a correlation of 0.793 between both methods (p < 0.001). Accuracy of Hertel measurement depended significantly from the examiners’ experience (< 5 (group 1), 5–15 (2) and > 25 (3) years, p = 0.042, Kruskal–Wallis analysis; p = 0.086 group 1 vs. 2, p = 0.014 group 1 vs. 3, p = 0.688 group 2 vs. 3, Mann–Whitney-U-test), reflected by levels of Pearson’s coefficient (correlation of both methods 0.691 (group 1), 0.837 (2) and 0.831 (3), respectively, p = 0.01). Generally, Hertel exophthalmometry correlates well with CT measurements. Subgroup analysis confirmed a superior quality of Hertel measurements in favour of experienced examiners. Teaching of accurate Hertel exophthalmometry should be improved. Assessment of exophthalmos using standardized criteria should be implemented for imaging reports.

Unsupervised Learning Identifies Computed Tomographic Measurements as Primary Drivers of Progression, Exacerbation, and Mortality in Chronic Obstructive Pulmonary Disease.

Rationale: Chronic obstructive pulmonary disease (COPD) is a heterogeneous syndrome with phenotypic manifestations that tend to be distributed along a continuum. Unsupervised machine learning based on broad selection of imaging and clinical phenotypes may be used to identify primary variables that define disease axes and stratify patients with COPD. Objectives: To identify primary variables driving COPD heterogeneity using principal component analysis and to define disease axes and assess the prognostic value of these axes across three outcomes: progression, exacerbation, and mortality. Methods: We included 7,331 patients between 39 and 85 years old, of whom 40.3% were Black and 45.8% were female smokers with a mean of 44.6 pack-years, from the COPDGene (Genetic Epidemiology of COPD) phase I cohort (2008-2011) in our analysis. Out of a total of 916 phenotypes, 147 continuous clinical, spirometric, and computed tomography (CT) features were selected. For each principal component (PC), we computed a PC score based on feature weights. We used PC score distributions to define disease axes along which we divided the patients into quartiles. To assess the prognostic value of these axes, we applied logistic regression analyses to estimate 5-year (n = 4,159) and 10-year (n = 1,487) odds of progression. Cox regression and Kaplan-Meier analyses were performed to estimate 5-year and 10-year risk of exacerbation (n = 6,532) and all-cause mortality (n = 7,331). Results: The first PC, accounting for 43.7% of variance, was defined by CT measures of air trapping and emphysema. The second PC, accounting for 13.7% of variance, was defined by spirometric and CT measures of vital capacity and lung volume. The third PC, accounting for 7.9% of the variance, was defined by CT measures of lung mass, airway thickening, and body habitus. Stratification of patients across each disease axis revealed up to 3.2-fold (95% confidence interval [CI] 2.4, 4.3) greater odds of 5-year progression, 5.4-fold (95% CI 4.6, 6.3) greater risk of 5-year exacerbation, and 5.0-fold (95% CI 4.2, 6.0) greater risk of 10-year mortality between the highest and lowest quartiles. Conclusions: Unsupervised learning analysis of the COPDGene cohort reveals that CT measurements may bolster patient stratification along the continuum of COPD phenotypes. Each of the disease axes also individually demonstrate prognostic potential, predictive of future forced expiratory volume in 1 second decline, exacerbation, and mortality.

Sarcobesity Index Predicts Poor Disease-Specific Survival After Resection for Colorectal Cancer

IntroductionSarcobesity (SO) is traditionally defined as the association between low muscle mass and obesity and has been reported to worsen prognosis after curative resection for colorectal cancer (CRC). This study aimed to propose a new definition of SO based on computed tomography measurements of the skeletal muscle area (SMA) and visceral adipose tissue (VAT) and to assess its implications on long-term survival after curative resection for stage I-III CRC. MethodsWe retrospectively analyzed 506 patients with stage I–III CRC who underwent surgery between January 2010 and December 2019. Preoperative computed tomography images were analyzed and the sarcobesity index (SI) was calculated for each patient as the VAT/SMA ratio. The optimal cutoff value for predicting survival was determined using time-dependent receiver operating characteristic analysis. Overall survival and disease-specific survival (DSS) were compared between SO (SI > 1.25) and non-SO (SI ≤ 1.25) patients. The rates and modes of recurrence were also compared between the two groups. ResultsThree hundred (59.3%) patients were identified to be sarcobese. No differences in short-term outcomes and administration of adjuvant chemotherapy were found, except for a longer length of stay in patients with SO. In a univariable analysis, SO was associated with a worse 5-y overall survival and DSS, considering the whole population and stages II and III separately. A multivariable analysis confirmed SO to be an independent risk factor for DSS (hazard ratio 2.29; 95% confidence interval 1.13-4.62, P = 0.02). Although the overall recurrence rate did not differ between the groups, a significantly higher rate of recurrence at multiple sites was observed in patients with SO (P = 0.01). ConclusionsThe SI, defined as per the VAT/SMA ratio, seems to be a reliable tool for identifying patients with worse DSS after potentially curative surgery for stage I-III CRC.

Calculation of Aortic VAlve and LVOT Areas by a Modified Continuity Equation Using Different Echocardiography Methods: The CAVALIER Study.

Background: The area of the left ventricular outflow tract (ALVOT) represents a major component of the continuity equation (CE), which is, i.a., crucial to calculate the aortic valve (AV) area (AAV). The ALVOT is typically calculated using 2D echo assessments as the measured anterior–posterior (a/p) extension, assuming a round LVOT base. Anatomically, however, usually an elliptical shape of the LVOT base is present, with the long diameter extending from the medial–lateral axis (m/l), which is not recognized by two-dimensional (2D) echocardiography. Objective: We aimed to compare standard and three-dimensional (3D)-echocardiography-derived ALVOT calculation and its use in a standard CE (CEstd) and a modified CE (CEmod) to calculate the AAV vs. computed tomography (CT) multi-planar reconstruction (MPR) measurements of the anatomical ALVOT, and AAV, respectively. Methods: Patients were selected if 3D transthoracic echocardiography (TTE), 3D transesophageal echocardiography (TEE), and cardiac CT were all performed, and imaging quality was adequate. The ALVOT was assessed using 2D calculation, (a/p only), 3D-volume MPR, and 3D-biplane calculation (a/p and m/l). AAV was measured using both CEstd and CEmod, and 3D-volume MPR. Data were compared to corresponding CT analyses. Results: From 2017 to 2018, 107 consecutive patients with complete and adequate imaging data were included. The calculated ALVOT was smaller when assessed by 2D- compared to both 3D-volume MPR and 3D-biplane calculation. Calculated AAV was correspondingly smaller in CEstd compared to CEmod or 3D-volume MPR. The ALVOT and AAV, using data from 3D echocardiography, highly correlated and were congruent with corresponding measurements in CT. Conclusion: Due to the elliptic shape of the LVOT, use of measurements and calculations based on 2D echocardiography systematically underestimates the ALVOT and dependent areas, such as the AAV. Anatomically correct assessment can be achieved using 3D echocardiography and adapted calculations, such as CEmod.

Particle tracking-based in-situ computed tomography measurement technique for advanced analytics of adhesive bonds

In the application field of adhesive bonding technology, the use of in-situ computed tomography (CT) opens up possibilities for detecting processes inside bonds that were hidden thus far. The present paper presents a successfully applied in-situ CT measurement technique, which allows the high-resolution measurement of displacements on the surface as well as within adhesive layers. The focus of the work was on the analysis of bulk specimen, bonded single-lap joints as well as butt joints under a stepwise increased load. In the experimental investigations, the specimens were stressed with technical strains ε and shears from 0.5% up to 25% and the resulting adhesive behaviour was observed in the form of measured displacements. Thus, in the analysis of bulk specimens, relaxation effects on the microscopic scale could be measured and visualized. Using single-lap joints and butt joints, both the displacements measured on the side face of the bondline and the displacements resulting within the adhesive volume could be measured and visualized at the highest resolution. In additional investigations, further potentially promising application examples could be shown, such as the supporting use of the in-situ CT measurement methodology for the derivation of characteristic values for the failure of bonded joints.

CT measurement of prostate volume using OsiriX® viewer is reliable, repeatable, and not dependent on observer, CT protocol, or contrast enhancement in dogs.

Computed tomography (CT) is an established method for evaluating dogs with suspected prostatic disease; however, publications assessing the effects of varying factors on prostate volume measurements are lacking. The objectives of this two-part, observer agreement, methods comparison study were to assess observer agreement and the effects of varying CT technical parameters for volume measurements of canine prostate glands on CT images using OsiriX® DICOM viewer software. In the first retrospective study, two observers measured prostate volumes of 13 client-owned dogs thrice on noncontrast and contrast CT images. In the second prospective study, two observers measured the prostate volume of 10 cadavers using five different CT protocols and eight cadavers using three slice thicknesses. Observer agreement analyses were performed, and prostatic CT volume measurements were compared with water displacement volume measurements. Intra- and interobserver variability and the effect of contrast enhancement were found to be minimal when a one-way analysis of variance model and intraclass correlation coefficients were used. No significant differences emerged between different protocols and slice thicknesses using a linear mixed effects model. When the prostate CT volume was compared using a Bland-Altman plot with the reference volume acquired by the water displacement method, agreement without consistent bias between the methods was shown, and over 90% of measurements were located within the 95% limits of agreement. The findings supported using OsiriX® software for CT prostatic volume measurements in dogs.

Kinetic process of upward gas hydrate growth and water migration on the solid surface

Gas hydrates have gained great interest in the energy and environmental field as a medium for gas storage and transport, gas separation, and carbon dioxide sequestration. The presence of small doses of surfactants in the aqueous phase has been reported to enhance hydrate formation; however, the underlying mechanisms remain poorly understood. Thus, in situ high-resolution X-ray computed tomography measurements were performed to monitor the upward water migration and the resulting hydrate nucleation and growth. It was found that the presence of hydrate crystals at the gas–liquid–solid contact line triggered the enhanced growth of hydrates on the reactor wall. A time delay was observed between the disappearance of the bulk water reservoir and its transformation into hydrate. The lower interfacial tension between the hydrate surface and the solution facilitated its adsorption onto the reactor wall once a thin film of hydrate nucleated on the solid wall surface. These hydrate layers present on the reactor wall were found to be porous, wherein the porosity decreased with increased subcooling. These fundamental results will be of value in understanding the mechanism of hydrate growth in the presence of surfactants and its potential application in hydrate-based technologies.

Sinogram interpretability based CT artefact reduction for multi-material workpieces

ABSTRACT Computed tomography (CT) is a technology for the simultaneous inspection of internal and external features of workpieces. However, beam hardening and scattered radiation artefacts caused by the different material densities and atomic numbers commonly confound CT measurements of multi-material workpieces. Multispectral CT (MSP CT) measurements reduce artefacts by combining multiple CT volumes performed with different x-ray spectra. However, all known simulation-based CT parameter optimisation approaches for industrial applications consider only the single-spectrum case. This paper investigates the CT radon space, focusing on sinogram interpretability. Multispectral CT x-ray spectra can be determined by defining and analysing sinogram areas corresponding to equivalent volume slice artefacts. Validation indicates that the two MSP CT spectra recommended via a proposed CT simulation considering critical sinogram areas cause an artefact reduction. Results are quantified by a standard deviation reduction of measured geometrical features.

Comparison of quantitative lung computed tomographic findings between idiopathic pulmonary fibrosis patients diagnosed by biopsy and by multidisciplinary discussion without biopsy

Objectives: We aimed to investigate the objective quantitative differences between the parenchymal computed tomography (CT) findings of idiopathic pulmonary fibrosis (IPF) patients diagnosed by surgical lung biopsy and by multidisciplinary discussion without biopsy. Methods: We performed parenchymal texture analyses in lung CT images of 116 IPF patients, 42 diagnosed by surgical lung biopsy, and 74 by multidisciplinary discussion without biopsy. The relative volumes of the ground-glass, reticular, honeycomb, hyperlucent, and normal parenchymal patterns were measured in six predefined sections of each lung by an automatic texture analysis software (CALIPER: Computer-Aided Lung Informatics for Pathology Evaluation and Rating). The results were compared between the two patient groups. Results: When the relative volumes of the parenchymal patterns were compared between the biopsied and non-biopsied groups in a total lung-based manner, the mean percentage of only the ground-glass pattern was significantly higher in the biopsied group. When compared between the corresponding lung sections, the percentages of the ground-glass pattern were higher in the biopsied group than those in the non-biopsied group at the bilateral central sections of the upper, middle, and lower lung zones. At the bilateral peripheral sections of the middle and lower lung zones, the sectional reticular pattern percentages were lower in the biopsied group than those in the non-biopsied group. Conclusions: CALIPER’s quantitative CT measurements revealed that the sectional relative volumes of the ground-glass and reticular patterns, but not of the honeycomb, normal, and hyperlucent parenchyma, were significantly different between some of the corresponding lung sections of the biopsied and non-biopsied IPF patients. This information may help a better understanding of the role of the CT findings in biopsy decisions and avoiding some of the unnecessary biopsies in suspected IPF patients.

Poster 225: Accuracy of 3D Printed Cutting Guide Versus Free-hand Technique for Anterior Closing Wedge Proximal Tibia Osteotomy in an Animal Model

Objectives:Anterior closing wedge proximal tibia osteotomy (ACWPTO) is an effective treatment for patients with elevated posterior tibial slope (PTS) and recurrent anterior cruciate ligament (ACL) injuries. However, the preoperative planning and surgical execution can be challenging, especially with limited surgeon experience and training. The purpose of this study was to evaluate the initial design of a 3D printed patient-specific cutting guide (PSG) for performing ACWPTO in an animal model. It was hypothesized that the PSG for ACWPTO will more accurately achieve the desired PTS correction compared to a traditional free-hand (FH) technique.Methods:Thirty cadaveric porcine knees underwent lateral radiographs and computed tomography (CT) scans, and were randomly assigned to ACWPTO by PSG or FH technique. Three knees within each group were then assigned to a 10°,12°,14°,16° or 18° correction. Knees assigned to the PSG group then underwent 3D modeling and a PSG was created in SolidWorks to complete the desired PTS correction (Figure 1). Knees assigned to the FH group were templated by an experienced orthopedic surgeon for performing ACWPTO by measuring a pre-determined wedge of bone to be removed from the anterior tibia. Surgeries were then performed by an experienced (attending physician), intermediate (resident physician), and novice surgeon (medical student). Each surgeon performed ACWPTO using the PSG and FH technique for each of the intended angles of correction (10°,12°,14°,16°,18°). Following ACWPTO, post-operative radiographs and CT scans were taken to measure the PTS and the accuracy was determined as the difference between the planned and actual PTS correction (Figure 2). The accuracy, surgical time, and radiation exposure were compared between surgeons using ANOVA. Further analyses to compare the variables of interest between the FH and PSG techniques were conducted using independent samples t-tests.Results:All data are summarized in Tables 1 and 2. Overall, we found the PSG to have significantly faster surgical time (6.4 +/- 2.2 minutes versus 12.0 +/- 3.9 minutes, p < 0.001) and less radiation exposure (8.7 +/- 4.9 mGy versus 58.7 +/- 28.1 mGy, p < 0.001). While the PSG trended towards increased accuracy with radiographic measurements of PTS, this did not reach statistical significance (1.6 +/- 1.6 degrees versus 2.9 +/- 2.0 degrees, p = 0.059). The highest accuracy was found for the resident (intermediate) surgeon using the PSG (0.5 +/- 0.5 degrees), which was significantly more accurate than FH technique for this surgeon (3.6 +/- 2.5 degrees, p = 0.026). Based on CT measurements of medial and lateral PTS we found the FH technique to be as accurate as the PSG (Table 2).Conclusions:One reason for the discrepancy between radiographic and CT measurements may be the lack of standardized methods for measuring PTS in porcine knees. The proximal tibia articular surface has a more complex geometry as compared to human knees, which did make measuring consistent landmarks challenging and is one of the primary limitations of this study. Other limitations of this study include the margin of error in the design of the 3D printed PSG, and accurate placement of the PSG on the proximal tibia. Guide placement was challenging if any cartilage remained around the tibial tubercle as this was not templated in the CT design. Also, PTS measurements can be highly dependent on limb rotation and observer experience. Despite these limitations, this study demonstrated the feasibility of a 3D printed PSG for performing ACWPTO in an animal model. This PSG was as accurate as the free-hand technique based on CT measurements and trended towards improved accuracy based on radiographic measurement of PTS. Future studies are planned to investigate this design in human cadaveric specimens.Table 1.Comparison of Results by Surgeon (Novice vs. Intermediate vs. Expert)Figure 1.A) 3D model of porcine tibia created in SolidWorks to create a patient specific cutting guide to perform anterior closing wedge tibial osteotomy. B) 3D printed patient specific cutting guide for anterior closing wedge tibial osteotomy.Table 2.Comparison of Results by Surgical Technique (Free-hand vs. Patient-Specific Guide)Figure 2.A) Pre-operative radiograph with measurement of posterior tibial slope. B) Post-operative radiograph after anterior closing wedge proximal tibial osteotomy performed with measurement of posterior tibial slope.

Characterization of a small-scale crystallizer using CFD simulations and X-ray CT measurements

• Single and multiphase CFD of a small-scale crystallizer with two stirrer types. • Indications when each stirrer is preferably used based on hydrodynamics. • X-ray CT applied in mixing studies used for the validation of the CFD simulations. Although small-scale crystallizers have gained increasing importance in recent years, their hydrodynamic properties have not yet been thoroughly studied. The purpose of this work is to characterize an intensively stirred small-scale crystallizer and to analyze whether its fluid mechanics behavior deviates from being homogeneously well-mixed. To this aim, single and multiphase computational fluid dynamics (CFD) simulations have been conducted. Two types of stirrers, including one overhead stirrer (OS) and one magnetic stirrer (MS), were compared. The single-phase CFD simulations showed that the mixing characteristics of the two stirrers differ significantly, thereby leading to variations in the distribution of solids. The MS is an axial flow type impeller, which is better at handling solid suspensions than the OS. The simulations were complemented by X-ray computed tomography measurements, which confirmed that spatial variations in solid distribution occur and that assuming a homogeneous suspension might lead to errors when modeling crystallization processes.

Foramen magnum ve kranyumun uyumu: Anatomik ve radyolojik bir çalışma

Purpose: The measurements’ reference points associated with foramen magnum (FM) and cranium were examined in this retrospective study. Also, the relation between FM and cranium harmony were calculated both on dry skull and in healthy subjects performed on computed tomography (CT). &#x0D; Materials and Methods: The present study was carried out on 185 healthy adult subjects (90 females; 95 males) aged between 18–67 years and 15 dried skull of unknown gender of an Anatolian population. The shapes of the FM were classified as two semicircle, oval, round, egg, tetragonal, pentagonal, hexagonal and irregular shapes. The anteroposterior length and transverse width of the FM and cranium were measured on both photos and CT. &#x0D; Results: The means and standard deviations of the measurements were given for three groups. To control the accuracy of FM width (FMW) and length (FML) results, a formula was used for three groups including dried skull and CT measurements of females and males, seperately (FMW=Cranial width (CW)/4.26 for group 1, CW/4.66 for group 2 and CW/4.66 for group 3; and FML=Cranial length (CL)/4.51 for group 1, CL/4.33 for group 2 and CL/4.16 for group 3). The oval type FM was predominant (26.67%) in dried skull and (23.33%) in females and (28.42%) in males.&#x0D; Conclusion: The present study presents noteworthy data about FM and cranium harmony of the adult Turkish population and dry skulls that will show a harmony between cranium and foramen magnum in clinical practice. There was no tetragonal and hexagonal FM types in dried skulls and tetragonal type FM was the least seen type in females and males.

Cephalometric Analysis of Sphenoid Sinus Dimensions for Sex Identification: A Radiologic Study

Background: Post-mortem identification of human remains with severe crushing and mutilating skeletal injuries from mass burials and natural disasters, is a challenging forensic procedure. Gender determination from skeletal remains requires a comparison between established ante-mortem data and post-mortem findings from mostly intact, easily recoverable parts of the skeleton, like the skull base sphenoid bone. Computed tomography, being the gold standard for radiological assessment of the paranasal sinuses, offers accurate and precise information about skeletal tissues. The aim of the study was to determine the sex of subjects from measurements of the sphenoid sinus using computerized tomography. Materials and Methods: Computerised tomography images of 323 adult sphenoid sinuses, obtained over a six-year period, from individuals whose ages ranged from 18 to 80 years were recruited, and the study was conducted at the Radiology Department of the Usmanu Danfodiyo University Teaching Hospital, Sokoto, following ethical approval. Images were taken with a GE Brightspeed Multidetector Helical CT Scanner, the anteroposterior, craniocaudal and transverse dimensions were measured on sagittal reformatted, axial and coronal reconstructed CT images respectively, and the volumes were determined. Measurements were taken in millimetres, between the widest points at the middle of the sinus walls from three-dimensional reconstructed images using the RadiAnt Version 4.2 (Medixant, 2017), powered by the Digital Imaging and Communication in Medicine (DICOM) viewer software. These images were viewed on bone windows. Results: Sinus volume and the transverse diameter, each correctly classified the sexes of subjects, in 60.4% of cases. However, when all the measured parameters of the sinus were analysed together as a single factor for sex determination, an overall value of 57.6% was obtained. Conclusion: Computerized Tomography measurements of sphenoid sinus dimensions could be useful in support of gender identification in unknown severely damaged human remains with speared sphenoid bone. Keywords: Sex, Sphenoid, CT, Forensic Anthropology

Skeletal Muscle Mass Measurement Using Cone-Beam Computed Tomography in Patients With Head and Neck Cancer.

Background and purposeHead and neck cancer (HNC) patients usually present with malnutrition during radiotherapy, leading to loss of skeletal muscle mass (SMM) and poor clinical outcomes. CT has been used in clinical practice for measuring SMM in cancer patients. However, its clinical application for monitoring SMM is limited by the expensive price and high radiation exposure. This study aimed to investigate the feasibility of cone-beam computed tomography (CBCT) for assessing SMM and its changes in HNC patients undergoing radiotherapy.Materials and methodsThis study was divided into two parts. In part 1 (n = 32), the cross-sectional of skeletal muscle area (SMA) at the third cervical vertebra (C3) based on CBCT and computed tomography (CT) was assessed. In part 2 (n = 30), CT and CBCT were performed, and patients’ weight was measured before and at four different time points during radiotherapy. SMAs at C3 were independently identified by three senior radiation oncologists. The interobserver agreement of SMA on CBCT (SMACBCT) findings was analyzed using the intraclass correlation coefficient (ICC). One-way analysis of variance was used to evaluate the interobserver variability and statistical significance for SMA measurements. CBCT and CT measurement differences and correlations were analyzed using paired sample t-test and Pearson correlation analysis, respectively. The Krouwer variant of the Bland–Altman plot was used to analyze the agreement of SMA measurements between CBCT and CT. A simple linear regression model was used to analyze the relationship of SMA measurements between the two imaging techniques, and the equation was established. A repeated-measures ANOVA was performed to evaluate the effects and interactions between weight loss, SMA loss, and time.ResultsSMACBCT demonstrated excellent interobserver reliability; no significant difference between SMACBCT and SMA on CT (SMACT) at C3 was observed in all patients. The SMACBCT and SMACT were highly correlated (r = 0.966; 95% confidence interval = 0.955–0.975; p < 0.001). Bland–Altman analysis revealed that SMACBCT was generally higher than SMACT. The predicted SMA value at C3 on CT using CBCT was similar to the actual value. Moreover, significant differences between SMA and weight loss (F =10.99, p = 0.002), groups (weight loss and SMA loss) and times (4 time points) (F = 3.93, p = 0.013), and mean percent loss over time (F = 7.618, p < 0.001) were noted.ConclusionCBCT may be used as an alternative for CT to measure SMA in HNC patients during radiotherapy.

Computed Tomography Assessment of Maxillary Sinus and Inferior Nasal Airway After Le Fort I Osteotomy.

This study aimed to evaluate and predict the factors that affect the postoperative maxillary sinus and inferior nasal cavity conditions after Le Fort I osteotomy. The rate of aerated (healthy) sinus area and the inferior nasal airway area were calculated by preoperative computed tomography measurements and at 1 week and 1 year postoperatively. Factors predicting the rate of aerated sinus area and the ratio of the inferior nasal cavity area after 1-week were examined using these variables. The subjects consisted of 112 patients (224 sides) who underwent Le Fort I osteotomy with sagittal split ramus osteotomy. The rate of aerated sinus area after 1 week was significantly correlated with sex, age, and amount of blood loss ( P < 0.0001). The rate of the inferior nasal cavity area after 1 week was significantly correlated with the anterior impaction amount of the maxilla and the preoperative rate of the inferior nasal airway area ( P= 0.0017). This study suggests that attention should be paid to females, older patients, and the amount of blood loss to prevent sinusitis, and larger maxillary impaction at the anterior site should be carefully planned to prevent severe nasal obstruction immediately after Le Fort I osteotomy.

Bedside Ultrasound for Ventricular Size Monitoring in Patients with PEEK Cranioplasty: A Preliminary Experience of Technical Feasibility in Neurotrauma Setting

BackgroundPosttraumatic hydrocephalus is a known complication after traumatic brain injury, particularly affecting patients undergoing decompressive craniectomy. Posttraumatic hydrocephalus monitoring in these patients represents a common issue in neurosurgical practice. Patients require periodical assessments by means of computed tomography (CT) scans. This study presents a preliminary institutional series in which ultrasound was used as a bedside imaging technique to monitor ventricular size in patients harboring a polyetheretherketone (PEEK) cranioplasty. Exploiting the PEEK cranioplasty permeability to echoes, we evaluated the feasibility of this bedside imaging method in monitoring hydrocephalus evolution, determining effects of ventriculo-peritoneal shunt, and excluding complications.MethodsEight patients with traumatic brain injury harboring PEEK cranioplasty following decompressive craniectomy were prospectively evaluated. Ultrasound measurements were compared with CT scan data taken the same day, and ventricular morphometry parameters were compared.ResultsUltrasound images through the PEEK cranioplasty were of high quality and intracranial anatomy was distinctly evaluated. A strong correlation was observed between ultrasound and CT measurements. Concerning distance between lateral ventricles frontal horns (IFH) and the diameter of the third ventricle (TV), we found a strong correlation between transcranial sonography and CT measurements in preventriculoperitoneal shunt (rho = 0.92 and p = 0.01 for IFH; rho = 0.99 and p = 0.008 for TV) and in postventriculoperitoneal shunt examinations (rho = 0.95 and p = 0.03 for IFH; rho = 0.97 and p = 0.03 for TV). The mean error rate between transcranial sonography and CT scan was 1.77 ± 0.91 mm for preoperative IFH, 0.65 ± 0.27 mm for preoperative TV, 2.18 ± 0.82 mm for postoperative IFH, and 0.48 ± 0.21 mm for postoperative TV.ConclusionsTranscranial ultrasound could represent a simplification of the follow-up and management of ventricular size of patients undergoing PEEK cranioplasty. Even if this is a small series, our preliminary results could widen the potential benefits of PEEK, not only as effective material for cranial reconstruction but also, in selected clinical conditions, as a reliable window to explore intracranial content and to monitor ventricular sizes and shunt functioning.

X-ray Stain Localization with Near-Field Ptychographic Computed Tomography.

Although X‐ray contrast agents offer specific characteristics in terms of targeting and attenuation, their accumulation in the tissue on a cellular level is usually not known and difficult to access, as it requires high resolution and sensitivity. Here, quantitative near‐field ptychographic X‐ray computed tomography is demonstrated to assess the location of X‐ray stains at a resolution sufficient to identify intracellular structures by means of a basis material decomposition. On the example of two different X‐ray stains, the nonspecific iodine potassium iodide, and eosin Y, which mostly interacts with proteins and peptides in the cell cytoplasm, the distribution of the stains within the cells in murine kidney samples is assessed and compared to unstained samples with similar structural features. Quantitative nanoscopic stain concentrations are in good agreement with dual‐energy micro computed tomography measurements, the state‐of‐the‐art modality for material‐selective imaging. The presented approach can be applied to a variety of X‐ray stains advancing the development of X‐ray contrast agents.

A 3-Dimensional Printed Patient-Specific Surgical Guide to Facilitate Transsphenoidal Hypophysectomy in Dogs.

ObjectiveHypophysectomy in dogs is a difficult surgery that requires specific learning and training. We aimed to evaluate the accuracy of a 3-dimensional printed patient-specific surgical guide to facilitate choosing the entry point in the basisphenoid bone before approaching the sella turcica during transsphenoidal hypophysectomy in dogs.MethodsTwo canine cadavers and 8 dogs undergoing transsphenoidal hypophysectomy for Cushing's disease treatment, involving design and fabrication of a 3-dimensional printed guide. The ideal entry point in the basisphenoid bone outer cortical layer was determined in each dog pre-operatively; its anatomical location was described with a set of measurements then compared to post-operative computed tomography measures describing the location of the outer cortical window created in the basisphenoid bone.ResultsSeveral guide designs were proposed, and a consensus reached based on surgeons' experience performing hypophysectomy. The device chosen could be applied to the size and shape of skulls encountered in this case series. The pre-planned measurements were comparable to post-operative measurement (there was also no statistical difference), with median of differences <0.1 mm, which we judged as clinically acceptable.Clinical SignificanceHypophysectomy in dogs is a challenging procedure that has a learning curve and needs to be performed by specialist neurosurgeons. We propose that a low-profile 3-dimensional printed surgical guide can aid the specialist neurosurgeon to locate the burring site of the outer cortical layer of the basisphenoid bone at a pre-defined location and with good accuracy. It does not alleviate the need to understand the anatomy of the region and to know how to create a slot within the basisphenoid bone, which remains essential to enter the sella turcica. This device could help specialist veterinary neurosurgeons wishing to be trained to perform hypophysectomy.