Computed Tomography Studies Research Articles

Liver X-ray Attenuation in Patients with Novel Coronavirus Infection (Multislice Computed Tomography Study)

Objective: to analyze the X-ray liver attenuation values in hospitalized patients with novel coronavirus infection (COVID-19) in relation to the time of disease onset, the severity of pulmonary parenchymal involvement, and the disease outcome.Material and methods. Chest computed tomography (CT) findings in 635 patients hospitalized with COVID-19 were analyzed. CT was performed at various times after the disease onset. The attenuation (CT density) values of the visualized liver upper part were measured by selecting the region of interest on CT images. The extent of the affected lung parenchyma was assessed according to the five-step CT0–4 scale, where CT0 corresponds to the absence of viral pneumonia, CT1 – lung parenchyma involvement less than 25%, CT2 – 25–50% lung volume lesion, CT3 – 50–75% lung volume lesion, CT4 – lung parenchyma involvement more than 75%.Results. In patients with CT0, the liver attenuation was significantly higher than in those with CT1, CT2, CT3, and CT4 (p < 0.01). During the first week of the disease, there was a decrease in liver CT density followed by its increase and return to the initial values (p < 0.0005). The dynamics of liver attenuation in the group of patients who died did not differ significantly from those who survived and recovered (p = 0.107). In the early stage of the disease (0–4 days), the liver attenuation in the group of patients who subsequently died turned out to be significantly lower than in the survivors (p < 0.05).Conclusion. The course of COVID-19 is characterized by a transient decrease in liver CT density. The reduction in liver attenuation does not correlate with the volume of the affected lung parenchyma in patients with CT2–4. The dynamics of liver CT density is not associated with the disease outcome. There is a trend towards more pronounced values of liver attenuation decrease in the early stage of the disease in patients who subsequently died, which requires further research.

Rostral nasopharyngeal CT measurements in Chihuahuas and Pomeranians are smaller than those measured in Dachshunds.

Chihuahuas and Pomeranians are often afflicted with obstructive upper respiratory tract disease. Previous computed tomographic (CT) studies have described the dimensions and abnormalities of different parts of the upper respiratory tract in brachycephalic dogs. However, Chihuahuas and Pomeranians were not included. The objective of this study was to determine the transverse-sectional (TSA) dimensions of the nasopharynx, cricoid, and trachea of Chihuahuas and Pomeranians, and investigate whether or not Chihuahuas and Pomeranians had smaller airway dimensions than another non-brachycephalic breed (Dachshund). A retrospective, descriptive, single-center cross-sectional cohort study was performed. CT studies of 88 dogs were included (42 Chihuahuas, 29 Dachshunds, and 17 Pomeranians). The TSA of the rostral, mid, and caudal aspect of the nasopharynx, the cricoid and trachea at the level of C4 were determined. For all these locations, TSA/weight, nasopharynx/cricoid, nasopharynx/trachea, and cricoid/trachea ratios were determined. The rostral nasopharynx was the smallest part of the upper airways in Chihuahuas and Pomeranians. Chihuahuas had significantly smaller rostral nasopharynx TSA/weight ratios compared to Dachshunds (P<0.0001). The rostral nasopharynx TSA/cricoid ratio and the rostral nasoharynx/trachea ratio for Chihuahuas were significantly smaller than both that of Pomeranians (P<0.0001 and P=0.00027) and Dachshunds (P<0.0001 and P=0.00084). Pomeranians had significantly smaller cricoid TSA/weight ratios compared to Chihuahuas (P=0.0014) and Dachshunds (P=0.00028). This study demonstrated that the nasopharynx is narrow in Chihuahuas and Pomeranians, with the smallest dimensions located at the rostral part of the nasopharynx.

CT and cross-sectional anatomy of the paranasal sinuses in the Holstein cow.

The structure of paranasal sinuses in cattle is difficult to understand due to its complexity, age-related changes, and insufficient published data. In this prospective, anatomic study, we described the anatomy of the paranasal sinuses in the Holstein cow using computed tomography (CT) and cross-sectional anatomic slices. Twelve healthy adult Holstein cow heads were used for this study. The heads were scanned using CT, and frozen anatomical sections were taken. The locations, borders, and relationships of the paranasal sinuses were defined on the anatomical sections and CT images. The paranasal sinuses on each side of the head consisted of conchal (dorsal, middle, and ventral), maxillary, lacrimal, palatine, frontal, sphenoid sinuses, and ethmoidal cells. The frontal sinus pneumatized all bones surrounding the cranial cavity, except for the ethmoidal and body of basisphenoid bones. The sphenoid and ventral conchal sinuses were the most asymmetrical, and the middle conchal sinus was the simplest. The ventral conchal sinus was detected in eleven animals, one of which was unilateral. This sinus communicated with the middle nasal meatus (13/21) and ventral nasal meatus (8/21). Findings can be used as background for interpreting CT studies of cattle with clinical signs of sinonasal region diseases. Future cross-sectional radiological and reconstructive anatomical studies and investigation of the postnatal development of related structures in cattle are needed.

Pattern of Endodontic Lesions of Maxillary and Mandibular Posterior Teeth: A Cone-Beam Computed Tomography Study.

The pattern of expansion of endodontic lesions in the jaws has been less commonly addressed in the literature. For this reason, the aim of this study is to assess the pattern of endodontic lesions of maxillary and mandibular posterior teeth using cone-beam computed tomography (CBCT). This cross-sectional study was conducted on 317 endodontic lesions of posterior teeth on CBCT scans retrieved from a radiology center in Qazvin, Iran, from 2020 to 2022. Endodontic lesions were assessed on sagittal, coronal, and axial sections by an endodontist and dental student using the Romexis software. The largest lesion diameter was measured occluso-apically, mesiodistally, and buccolingually. Lesion size was analyzed based on age, gender, jaw, tooth type, and presence/absence of root filling by independent samples t-tests and a one-way Analysis Of Variannce (ANOVA). The largest diameter of lesions in the maxilla and mandible was recorded in the occluso-apical dimension followed by buccolingual and mesiodistal dimensions (p > 0.05). The pattern of lesions was the same in teeth with and without endodontic treatment, but it was significantly different in maxillary and mandibular endodontically treated teeth in the occluso-apical and buccolingual dimensions (p < 0.05). No significant correlation was noted with tooth type or jaw except for maxillary and mandibular first molar lesions, which were significantly different in the occluso-apical dimension (p < 0.05). Lesion size in all three dimensions was significantly greater in males than females (p < 0.05), and was the highest in the occluso-apical dimension in both genders. In the maxilla, the mean lesion size significantly decreased in the mesiodistal dimension with age (p < 0.05). In conclusion, the largest lesion diameter in the maxilla and mandible was found in the occluso-apical dimension, indicating the role of bone density in the pattern of lesions.

Features of the use of «Kollapan-L» when raising the mucous membrane of the bottom of the maxillary sinus

In a significant number of patients suffering from partial absence of teeth, computed tomography determines a deficiency of bone tissue in the area of missing teeth. This in turn complicates the placement of dental implants. The modern dental market is widely represented by various osteoconductive and indifferent materials that allow restoring the missing volume of bone tissue. An analysis of the literature data demonstrates the highest efficiency of osteoconductive materials. Their most effective representative is Kollpan-L®. Target. To determine the features of the clinical use of Kollapana-L® during closed sinus lift. Materials and methods. Patient M., aged 54, complained of a partial absence of teeth in the upper jaw. When conducting a computed tomography study, it was revealed the need to use the osteoplastic material «Kollapan-L»® during the operation of a closed sinus lift. Conclusion. As a result of the study, it was revealed that the use of osteoplastic material «Kollapan-L»® allows to reduce various postoperative complications (pain, swelling), and also promotes accelerated regeneration of bone tissue in the area of the defect.

A computed tomography study investigating the effects of botulinum toxin injections prior to complex abdominal wall reconstruction

ObjectiveTo explore how intramuscular injection of botulinum toxin A (BTA) affects the lateral abdominal wall (LAW) musculature, abdominal- and hernia dimensions, and muscle structure on computed tomography (CT) in patients scheduled for complex abdominal wall reconstruction (CAWR).MethodsRetrospective analysis of prospectively registered patients who received bilateral intramuscular BTA injections into all three muscles of the LAW. Only patients for which a CT was available before and 3–6 weeks after BTA treatment prior to surgery were analyzed.ResultsFifty-two patients were analyzed. Median hernia width in all patients decreased with 0.4 cm (IQR − 2.1;0.6) (p = 0.023). Median intra-abdominal transverse diameter increased with 0.9 cm (IQR − 0.2;3.3) (p = 0.001) and the intra-abdominal anterior–posterior diameter decreased with 0.5 cm (IQR − 1.3;0.5) (p = 0.017), making the abdomen more oval. Median LAW muscle length increased with 0.9 cm (IQR 0.0;2.4) per side (p < 0.001), muscle thickness decreased with 0.5 cm (IQR − 0.8;− 0.2) (− 25.0%) per side (p < 0.001), and muscle mass decreased with 3.9 cm2 (IQR − 6.4;-1.5) (− 15.8%) per side (p < 0.001). Median HU of the psoas muscles (density) increased with 4.8 HU (IQR 0.4;9.7) (10.3%) per side (p < 0.001). Effects of BTA were more pronounced in patients with a loss of domain (LoD) ≥ 20%.ConclusionsThe main effect of BTA injections is elongation and thinning of the LAW muscles, more than a decrease in hernia width. Concomitantly, the abdomen becomes more oval. An increase of psoas muscles density is seen, associated with offloading of the LAW muscles. Patients with large LoD have a proportionally higher effect of BTA.

Evaluation of Cribriform Plate Dimensions and Middle Turbinate Length in Patients With Vomeral Agenesis: A Computed Tomography Study.

The cribriform plate and attachment area of the middle turbinate are anatomical structures that may potentially be injured during septoplasty and/or endoscopic sinus surgery. The purpose of this study is to compare the cribriform plate and middle turbinate length dimensions between patients with vomer agenesis (VA) and the control group using paranasal sinus computed tomography (CT). Paranasal sinus CTs performed in our hospital between January 2011 and January 2021 were evaluated and patients with VA were identified. A control group was created from patients who underwent paranasal sinus CT for various reasons during the same date interval. The cribriform plate and middle turbinate lengths were statistically compared between the groups. A total of 10,095 paranasal sinus CTs were evaluated and 54 patients with VA were identified. Seven patients with VA were excluded from the study because their measurements could not be made accurately. Forty-seven VA patients were included in the study group, while 94 patients were included in the control group. There was no statistical difference in cribriform plate dimensions (medial ethmoid roof plate height, cribriform plate height, cribriform plate lateral lamella height and width) between the groups (for all dimensions P >0.05). The middle turbinate length was significantly higher in the VA group (for right and left P =0.020 and 0.011, respectively). These findings theoretically suggest that the risk of cribriform plate injury during septoplasty and/or endoscopic sinus surgery is similar in patients with or without VA.

Challenges Associated with Effective Implementation of CT Dose Check Standards and Radiation Monitoring Index in Computed Tomography: Healthcare Sector Experience

Computed tomography (CT) radiation dose management tools should be used whenever possible, particularly with the increasing demand for acquiring CT studies. Herein, we aim to assess the advantages and challenges faced with implementing two CT dose management tools. A second aim was to highlight CT examinations exceeding dose notification values (NVs) and define the common set of causes. A total of 13,037 CT examinations collected over a six-month period, were evaluated, using two independent CT dose management tools, a CT Dose Notification prospective-view tool (PVT) following CT Dose Check standards and a retrospective statistical-based view tool (RSVT). Dose NVs were set to twice the Local Diagnostic Reference Levels. There was a significant discrepancy between dose NV counts registered with prospective (4.15%) and retrospective (7.98%) tools using T-Test. A core difference is the dose configuration setup, with PVT and RSVT being dose per series and whole study, respectively. Both prospective and retrospective dose management tools were equally useful despite their technical difference. Configuring the CT prospective dose notification check tool using NVs that is based on DRLs has limitations, and one needs to establish dose NVs per series to overcome this technical hurdle. Technical challenges make the implementation of CT Dose Check standards puzzling.

Lunate Fracture Morphology in Kienbock's Disease-A Computed Tomography Study.

Background The pathogenesis of Kienbock's disease is poorly understood. The coronal fracture line is acknowledged as a poor prognostic marker in the disease. Other fracture types in the Kienbock's wrist have subsequently been identified. Questions/Purposes The aim is to study the fracture morphology of the lunate in a cohort of patients using computed tomography. Methods Patient images were acquired using a set protocol with four-dimensional computed tomography scanning. Images were reviewed by two orthopaedic surgeons and a consultant radiologist. Static and dynamic images were assessed and a fracture map created. The relationship of fracture type to other parameters was then analyzed. Results Twenty-three patients were included in the study, including 11 males and 12 females, with a mean age of 43 years. Total frequency of fracture lines in the cohort was coronal - 26, proximal subchondral bone plate type - 24, avulsion - 19, sagittal - 16, and distal subchondral bone plate type - 11. There were statistically significantly more proximal than distal subchondral bone plate fractures ( p = 0.03), and more coronal fractures than distal subchondral bone plate fractures ( p = 0.01). There were statistically significantly more radiolunate ligament-avulsion types ( p <0.001) than other types. The sagittal fracture line through the lunate approximated closely to the ulnar edge of the capitate and the ulnar edge of the radius. Conclusion Study on the fracture morphology in the Kienbock's wrist has improved our understanding of the disease pathogenesis. Fracture lines may correspond to loading points, intrinsic and extrinsic ligament avulsions. These fracture types may play a role in disease progression and are important to identify when considering lunate salvage surgery.

An Anatomical, Sonographic, and Computed Tomography Study of the Transversus Abdominis Plane Block in Cat Cadavers.

Simple SummaryThe transversus abdominis plane (TAP) block is a locoregional technique used for postoperative analgesia after abdominal surgery, reducing the consumption of systemic analgesic drugs. The aim of this cadaveric study was to evaluate the spread of an anaesthetic-contrast dye solution administered by an ultrasound-guided 1-point (lateral; TAP-L approach) or 2-point (subcostal and lateral; TAP-SL approach) TAP block technique. Contrast distribution was assessed by computed tomography whereas nerve staining was assessed by anatomical dissection. The 2-point-injection technique provided a wider injectate spread within the TAP than the 1-point technique. Further clinical studies are warranted to investigate the analgesic effect of these TAP block approaches in cats undergoing abdominal surgery.This study compared the distribution of a bupivacaine–iopamidol–dye solution following ultrasound-guided in-plane TAP injection using a 1-point (TAP-L) or 2-point (TAP-SL) approach in cat cadavers. Two cadavers were used to study the TAP sonoanatomy while eight cadavers were enrolled in a randomized, prospective, blinded investigation. Each cat randomly received a TAP-L with 0.5 mL/kg in one hemiabdomen and a TAP-SL with 0.25 mL/kg/point in the contralateral hemiabdomen. After injection, computed tomography and dissection were performed to assess contrast distribution and number of stained target nerves. TAP-SL resulted in a wider contrast spread (mm) compared with TAP-L (87 ± 7 versus 71 ± 9; p = 0.002). The prevalence of nerve staining was higher using TAP-SL than TAP-L (p = 0.001). The ventral branches of T10, T11, T12, T13, L1 and L2 were stained in 2/8, 2/8, 5/8, 7/8, 4/8 and 1/8, and in 7/8, 7/8, 8/8, 8/8, 8/8 and 1/8 using TAP-L and TAP-SL approaches, respectively. Computed tomography and dissection identified minimal injectate intraperitoneally or within the falciform ligament fat following 1 TAP-L and 2 TAP-SL. Ultrasound-guided TAP-SL provided better injectate distribution around the thoracolumbar spinal nerve branches than TAP-L.

Many hands make light work. Echocardiography and computed tomography results from the Tricuspid Regurgitation IMAging (TRIMA) study

Abstract Background Anatomic knowledge of the tricuspid valve (TV) is the first step in the diagnostic algorithm of patients with tricuspid regurgitation (TR), who are candidates for transcatheter tricuspid valve intervention (TTVI). Currently, echocardiography and computed tomography (CT) are available instruments to study the TV anatomy, guide the decision-making process and support the development of novel transcatheter therapies. Purpose The Tricuspid Regurgitation IMAging (TRIMA) study aimed to correlate CT parameters to commonly used echocardiographic variables. Methods This prospective, single-center study enrolled 22 consecutive patients with TR equal to or greater than severe (≥3+). All patients underwent transthoracic echocardiogram (TTE), transesophageal echocardiogram (TEE) and cardiac CT study, in order to obtain anatomical dimensions of the tricuspid annulus and quantification of right-chambers remodeling and function. Novel CT scan measurements were analyzed. Correlation between measurements on echocardiography and CT imaging was assessed. Results Severe TR (3+) was present in 27.4% patients, massive (4+) in 4.8% and torrential (5+) in 3.2%. The mean right ventricle (RV) length, RV mid diameter, and right atrium area were 60.81±9.11 mm, 41.27±7.67 mm and 31.72±9.66 cm2, respectively. Tricuspid annular plane excursion, fractional area change, longitudinal myocardial velocity (S') were 16.09±3.25 mm, 33.36±9.47% and 9.18±1.94 cm/sec, respectively. The annular dimensions obtained by CT scan were generally observed to reduce from diastole to systole, except for eccentricity, angles and distance between the postero-septal and antero-posterior commissure and distance between centroid and antero-posterior commissure. A Kruskal-Wallis test showed a stepwise increase in the tricuspid anatomical regurgitant orifice area (AROA) values by CT across the expanded TR grades by TEE, χ2(2)=6,466, p=0.039. Using the Pearson correlation coefficient, we found a relationship between the AROA and TR grade (r=0.593; p&amp;lt;0.004), as well as ARO-perimeter and TR grade (r=0.470; p&amp;lt;0.027). Additionally, a significant correlation was found between septal lateral annulus diameter obtained by TEE and CT (r=0.637; p=0.001). Anyway, no correlations were found between novel CT variables and TR grade or RV function assessed by echocardiogram, as well as between CT systo-diastolic annulus variability and RV function. Conclusions Standard echocardiographic study provide invaluable information about the anatomy and function of the right-chambers, as well as an accurate grade of TR. Conventional and novel variables derived by CT scan may step up the anatomical assessment of the complex morphology of the TV apparatus, thanks to the high spatial resolution of the technique. Therefore, an integrated multimodality assessment is the key point of the screening process of TR candidates for TTVI. Funding Acknowledgement Type of funding sources: None.

Long-term toxicity of radiosurgery for ablation of ventricular tachycardia

Abstract Introduction There is a rising interest in using radiosurgery to modify arrhythmogenic substrate in patients with recurrent VT. However, data on the safety are still inadequate. Purpose This is update of toxicity evaluation based on the compilation from our case series, NIRA-VT and STAR-VT. Methods Between 2014 and March 2021, 36 patients (33 male, 3 females; mean age 66±10 years) with structural heart disease (ischemic cardiopathy, dilated cardiopathy or fibroma associated scar) from two electrophysiology centers in the Czech Republic (Trinec, Prague) underwent radiosurgery for recurrent VT. Radiosurgery was performed after at least one failed catheter ablation for VT. The critical part of the VT substrate was identified by electroanatomic mapping using a combination of voltage mapping, pace mapping, and activation mapping; and it was marked on a contrast-enhanced computer tomography study as a CTV. In NIRA-VT trial, CTV included scar based on PET/CT evaluation. Radiosurgery system with real-time motion tracking using the tip of the electrode of an indwelling defibrillator as a fiducial marker was used. A total radiation dose of 25 Gy was delivered to the ablation target in a single session during free breathing. Radiation-induced toxicity was evaluated according to the Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Only patients with follow up longer than 6 months were included in long term radiation related side effects evaluation. Results The mean CTV and PTV were 26±11 ml and 41±22 ml respectively. No patient exhibited acute (up to 3 months) elevation of troponin, pericardial effusion, or a decrease in left ventricular ejection fraction from baseline. Four patients developed acute mild nausea, which waned after antiemetic drugs. Long-term radiation related side effects were evaluated in 19 patients. Two patients (11%) presented radiological signs of lung fibrosis in small area in close distance from PTV. There was no significant decrease in left ventricular ejection fraction during follow up. Six patients (33%) gradually developed significant progression of known mitral regurgitation after SBRT, two (11%) of them had to undergo mitral valve replacement (grade 4 toxicity). Two cases of esophagitis (12%) were seen with one radiation toxicity related death (grade 5 toxicity) due to the unresectable esophagi-pericardial fistula (6%). Conclusions Our data indicate the feasibility of radiosurgery, majority of patients presented no/mild radiation related toxicity and decrease of VT burden. However, we have seen three cases of grade 4,5 toxicity. To further investigate long-term safety and efficacy of radiosuergery for VT, enrolling into a randomized prospective study is in progress. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): European Union's Horizon 2020

Anatomical Variations of the Maxillary Sinus – A Cone Beam Computed Tomography Study

Abstract Objectives: The knowledge of the normal morphology of the maxillary sinuses and their variations is important for maxillofacial radiologists to achieve a better evaluation and delineation of pathologies and for pre-implant evaluation of the maxilla. The aim of our study was to evaluate anatomical variations of maxillary sinuses using Cone Beam Computed Tomography (CBCT). Materials and methods: 150 CBCT images where bilateral maxillary sinuses were scanned were included in the study following the inclusion and exclusion criteria. 75 CBCT scans each of males and females were studied using the Planmeca Romexis software (Version 4.6.2). Multiplanar images were searched for the presence of anatomical variations such as septae, haller cells and ethmomaxillary sinus. The data were subjected to Chi square test using SPSS software to compare and relate gender and site based differences in the occurrence of the anatomical variations. Results: Sinus septa was the predominant variation in both males and females with significantly higher prevalence in females and on the right side. An ethmomaxillary sinus was seen significantly more often in males, while Haller cells did not show any gender based differences in their occurrence. Ethmomaxillary sinus and Haller cells showed no difference in occurrence on the right and left side. Conclusions: Anatomic variations of the maxillary sinuses are a common finding. It necessary for the clinicians to be familiar with these variations to avoid clinical complications especially in cases of implant placements.

Assessment of skeletal relationships in cleft palate with or without cleft lip: A cone-beam computed tomography study in a pakistani population.

Understanding the different skeletal relationships in orofacial clefts by using cone-beam computed tomography (CBCT) may eventually lead to developing better diagnosis and treatment protocols for facial deformities. The objective of this study was to investigate the different skeletal relationships in the cleft palate with or without cleft lip (CP ± L), using CBCT scans. This is a retrospective study conducted at the Orthodontics and Oral Radiology department, CMH-Lahore medical college and Institute of dentistry. In the current study, 4,152 CBCT scans (dcm format) were collected from a radiology center in Lahore, Pakistan between February 2015 and February 2018. All CBCT scans were imported to the Romexis Viewer, version 4.4.0 (Planmeca, Finland). Data sorting was performed to identify age, sex, cleft phenotype, unilateral cleft quadrant, sagittal skeletal relationship, and facial soft tissue involvement. Statistics were generated, using the Chi-square test. A P value <0.05 was considered statistically significant. We identified 73 cases of CP ± L in the sample. The male-to-female ratio was 1.21:1. Bilateral cleft lip and palate (BCLP) mostly affected males (60%), whereas unilateral cleft lip and palate (UCLP) mainly affected females (57.6%), with a left-side female predominance. The different cleft phenotypes do not show any statistically significant difference regarding skeletal relationships and sex (P > 0.05). Skeletal class III relationships were found to be predominant in both sexes, followed by class II, and class I skeletal relationships. Henceforth, such CP ± L patients should be pre-emptively screened in early life to avoid such skeletal complications.

Morphological variation of nasopalatine canal: A cone-beam computed tomography study

Aim: 1) to assess the morphological variation of the nasopalatine canal (NPC) concerning age and gender. 2). to assess the correlation between the gender and morphology of the canal. 3). to assess the correlation between age and length of the canal.Materials and Methods: This is a retrospective, randomized observational study. The study comprised of 60 CBCT scans of maxilla showing NPC completely. The patients were in the age range of 15-75 years. Scan of 25 females and 35 males were included in the study. Patient below 15 years of age and NPC pathology or impacted teeth in same region were excluded in the study. The scans were obtained using ICAT17 19 machine and analyzed Vision software. Cone Beam 3D Imaging Machine operating at 120 kvp, 37.07 mAs with 0.25 mm voxel size, and a field of view of 16 × 6 cm maxilla.Results: Nasopalatine canal has 4 different morphological shapes. The most common shape was the cylindrical shape amongst both males and females. The least common shape was found to be hourglass shape with increasing age the length of NPC was found to decrease. The length of the canal was found to be longer in males when compared to femalesConclusion: This study highlights the importance of NPC morphology before or during surgical procedures involving the maxilla.

Assessing the long-term in vivo degradation behavior of magnesium alloys - a high resolution synchrotron radiation micro computed tomography study

Biodegradable magnesium (Mg) implants are emerging as a potential game changer in implant technology in situations where the implant temporarily supports the bone thereby avoiding secondary surgery for implant removal. However, the consequences of the alteration in the degradation rate to bone healing and the localization of degradation and alloying products in the long term remain unknown. In this study, we present the long-term osseointegration of three different biodegradable Mg alloys, Mg-10Gd, Mg-4Y-3RE and Mg-2Ag, which were implanted into rabbit femur for 6 and 9 months. In addition, we have investigated the effect of blood pre-incubation on the in vivo performance of the aforementioned alloys. Using high-resolution synchrotron radiation based micro computed tomography, the bone implant contact (BIC), bone volume fraction (BV/TV) and implant morphology were studied. The elemental traces have been characterized using micro X-ray fluorescence. Qualitative histological evaluation of the surrounding bone was also performed. Matured bone formed around all three implant types and Ca as well as P which represent parts of the degradation layer were in intimate contact with the bone. Blood pre-incubation prior to implantation significantly improved BIC in Mg-2Ag screws at 9 months. Despite different implant degradation morphologies pointing toward different degradation dynamics, Mg-10Gd, Mg-4Y-3RE and Mg-2Ag induced a similar long-term bone response based on our quantified parameters. Importantly, RE elements Gd and Y used in the alloys remained at the implantation site implying that they might be released later on or might persist in the implantation site forever. As the bone formation was not disturbed by their presence, it might be concluded that Gd and Y are non-deleterious. Consequently, we have shown that short and mid-term in vivo evaluations do not fully represent indicators for long-term osseointegration of Mg-based implants.

Radiological Evaluation of Tympanic Segment of Chorda Tympani Nerve in Normal Ears: An Ultra-High-Resolution Computed Tomography Study

To visualize the course of the tympanic segment of chorda tympani nerve (CTN) using ultra-high-resolution computed tomography. A hundred and fourteen ears with no evident otologic pathologies were included. The tympanic segment of CTN was divided into 4 portions as follows: periannular, posteromalleal, malleal, and anteromalleal. The length of the periannular portion running along the tympanic annulus was recorded. Four points of interest (the beginning and end of the posteromalleal and anteromalleal portions) were selected to perform distance measurements relative to the tip of the malleus manubrium. Differences in lengths and distances were compared in terms of ear sides and sexes. The length of the periannular portion was 2.49±1.16mm. The beginning of the posteromalleal portion was located more laterally on the right side than on the left side (mean: 4.09mm vs. 3.92mm;, P=0.016). The end of the posteromalleal portion was located more inferiorly on the right (mean: 2.11mm vs. 2.26mm; P=0.018). The beginning of the anteromalleal portion on the right was located more laterally than that on the left (mean: 2.60mm vs. 2.45mm; P=0.027). The start and end of the anteromalleal portion were more posteriorly located in women than in men (both Ps<0.001). The course of the tympanic segment of normal CTN was comprehensively visualized by ultra-high-resolution computed tomography. Preoperative evaluation of the tympanic segment of CTN might be helpful in avoiding iatrogenic injury during middle ear surgery.

Comparison of Tibial Geometry, Density, and Strength in College-Aged Female Eumenorrheic Dancers, Gymnasts, and Runners: A Peripheral Quantitative Computed Tomography Study

Weightbearing activities such as gymnastics, soccer, weightlifting, and running have often been used as benchmarks in skeletal research since they have been shown to promote densitometric and geometric benefits. In comparison with other sports, there is a paucity of information in relation to dance and its osteogenic potential. This study aimed to compare tibial geometry, density, and strength in college-aged dancers versus gymnasts and runners.<br/> Methods: A total of 60 trained eumenorrheic collegiate-aged female dancers (n = 11), gymnasts (n = 11), runners (n = 19), and sedentary controls (n = 19) were included in the study. Bone measure- ments, including total area (ToA), volumetric (total vBMD) and cortical density (CoD), compressive bone strength (BSI), and polar strength stress index (SSIp) of the dominant limb, were assessed using peripheral quantitative computed tomography (pQCT) at the distal and proximal tibia (4% and 66% of limb length).<br/> Results: No significant differences in ToA, CoD, CoA, and total vBMD were found between dancers and the comparison athletes at the measured sites. In addition, strength indices (BSI and SSIp) at the distal and proximal sites were similar between the dancing and both athlete groups.<br/> Conclusion: Results suggest dance elicits similar structural adaptations at the tibia compared to benchmark high-impact and repetitive impact sports; thus, indicating dance, in its various forms, can have a positive effect on important bone variables that influence density and strength. These adaptations may potentially delay or prevent bone fragility later in life. Future studies should compare individual styles of dance separately, longitudinally, and include other important lower (e.g., hip) and upper body (e.g., radius) sites to further identify which forms provide the greatest osteogenic benefits.

Assessment of infrazygomatic crest dimensions in different vertical facial growth types for miniscrew insertion: A cone-beam computed tomography study

This study aimed to assess the depth and height of the infrazygomatic crest (IZC) located in the posterior maxilla at the junction with the zygomatic process in patients with different vertical facial growth types as a potential miniscrew insertion site. The sample consisted of cone-beam computed tomography scans of 117 patients (42 males and 75 females), with a mean age of 22.9 ± 2.7. The population was divided into 3 groups according to the measured SN-GoGn angle: Decreased facial proportions (n= 28), average facial proportions (n= 62), and increased facial proportions (n= 27). Bone depth was assessed at 5 levels: apex, 1, 2, 3, and 4 mm vertically from the apex. The measurements were performed on the mesiobuccal and distobuccal roots of the first molar and the mesiobuccal root of the second molar. Repeated-measure analysis of variance followed by univariates analyses and Bonferroni multiple comparisons were performed to compare the mean bone thickness between groups. The IZC height was assessed through a vertical line ranging from the furcation of the maxillary first molar to the sinus floor. Analysis of variance followed by Tukey (honestly significant difference) post-hoc tests was used to compare the mean height between groups. Mean bone depth between the 3 groups were significantly different at the mesiobuccal root region of the first molar at all the measured levels. It was smaller for average, intermediate for decreased, and elevated for increased facial proportions. No statistical difference was shown at the distobuccal root of the first molar except for the apex level and the mesiobuccal root of the second molar except for the apex and 4 mm levels. The mean bone height was significantly different between subjects with increased facial proportions and the 2 other groups. Subjects with increased facial proportions tend to present a longer and deeper IZC followed by decreased facial proportions, then average facial proportions.

The prevalence of Stafne bone cavity: A meta-analysis of 355,890 individuals

Background/purposeA Stafne bone cavity (SBC) is an incidental depression in the lingual surface of the mandible. The aim of this study is to provide pooled estimates of the frequency of Stafne bone cavity and to correlate its presence with such variables as sex, laterality, diagnostic methods and population. Materials and methodsPotential studies were searched through four electronic databases: Google Scholar, PubMed, Scopus, and Journal Storage. Titles, abstracts, and full texts of the articles were screened. ResultsA total of 54 studies relating to 355,890 subjects met the inclusion criteria for meta-analysis. A meta-analysis using the DerSimonian-Laird model revealed an overall prevalence of 0.17% (CI:0.14%–0.21%, I2 = 80.7%). SBC was four times more common in males than females (z = 6.94, P < 0.01), and was unilateral in almost all cases (z = 12.90, P < 0.01). Radiographic studies yielded a lower SBC prevalence at 0.12% (CI:0.09%–0.15%, I2 = 71.7%) than computed tomography studies, skeletal studies and excavation studies. Ancient populations had three times higher SBC prevalences (0.47%, CI:0.21%–0.73%, I2 = 89.5%) than the average populations today (z = 3.21, P < 0.01). ConclusionThe prevalence of Stafne bone cavity is approximately 0.17%, and was four times more prevalent in males than females. This variant bone cavity was also present unilaterally in the majority of cases. Awareness of SBC is important for dentists, maxillofacial surgeons and other practitioners performing routine dental practices and interpreting panoramic radiographs.