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Journal of Endodontics Sep 2018Manufacturers offer single-file instrumentation systems with matching gutta-percha (GP) cones to simplify root canal preparation and obturation. The purpose of this...
INTRODUCTION
Manufacturers offer single-file instrumentation systems with matching gutta-percha (GP) cones to simplify root canal preparation and obturation. The purpose of this study was to determine whether file diameters and tapers match with corresponding cone diameters and tapers (precision) as well as industry standards (accuracy).
METHODS
Twenty files and corresponding GP cones from each size of F360 (#25, #35, #45, #55 with .04 taper) and Reciproc (#25, #40, #50 with variable tapers) instruments were examined by using optical microscopy (×32) to determine their diameter and taper. Precision was evaluated by using one-way analysis of variance (α = 0.05) with Scheffé post hoc tests and t tests with Bonferroni correction. Accuracy was calculated by subtracting the nominal values from the measured values of all files and GP cones, and mean diameter and taper differences were compared by using one-way analysis of variance (α = 0.05) and Scheffé post hoc test for pairwise comparison.
RESULTS
For F360, the majority of file and cone diameters were within the tolerance levels, but most of the file diameters were significantly larger than GP cone diameters (P < .05), but the majority of all measured values were within the tolerance levels. For Reciproc, file and cone diameters at D1 and D3 mostly approached the nominal values. At the coronal end, file diameters #25 and #50 were significantly smaller than cone diameters (P < .05). For both instrumentation systems, almost all file and cone tapers matched with the preset tolerance ranges. For Reciproc, significant differences between file and GP cone demonstrated either smaller cone or smaller file diameters and tapers, depending on the size. Most of the measured values were within the acceptable range, but diameters at the coronal end exhibited the highest percent difference from the nominal values.
CONCLUSIONS
Despite the call for standardization, variability in diameter and taper dimensions between single-file instrumentation systems and their corresponding GP cones can be expected.
Topics: Alloys; Dental Instruments; Dental Pulp Cavity; Equipment Design; Gutta-Percha; Root Canal Filling Materials; Root Canal Obturation; Root Canal Preparation
PubMed: 30078573
DOI: 10.1016/j.joen.2018.06.005 -
Northern Clinics of Istanbul 2023The aim of this study was to determine normative reference values for major thoracic arterial vasculature in Turkiye and to evaluate differences according to age and...
OBJECTIVE
The aim of this study was to determine normative reference values for major thoracic arterial vasculature in Turkiye and to evaluate differences according to age and gender.
METHODS
Low-dose unenhanced chest computerized tomography images acquired with pre-diagnosis of COVID-19 between March and June 2020 were evaluated retrospectively. Patients with known chronic lung parenchymal disease, pleural effusion, pneumothorax, chronic diseases such as diabetes, hypertension, obesity, and chronic heart diseases (coronary artery disease, atherosclerosis, congestive heart failure, valve replacement, and arrhythmia) were excluded from the study. The ascending aorta diameter (AAD), descending aorta diameter (DAD), aortic arch diameter (ARCAD), main pulmonary artery diameter (MPAD), right pulmonary artery diameter (RPAD), and the left pulmonary artery diameter (LPAD) were measured in the same sections by standardized methods. The variability of parameters according to age (<40 years; ≥40 years) and gender (male to female) was evaluated by statistical methods. The Student's t test was used to compare the normal distribution according to the given quantitative age and gender, while the data that did not fit the normal distribution were compared with the Mann-Whitney U test. The conformity of the data to the normal distribution was tested with the Kolmogorov-Smirnov, Shapiro-Wilk test, and graphical examinations.
RESULTS
Totally 777 cases between the ages of 18-96 (43.80±15.98) were included in the study. Among these, 52.8% (n=410) were male and 47.2% (n=367) were female. Mean diameters were 28.52±5.13 mm (12-48 mm in range) for AAD, 30.83±5.25 mm (12-52 mm in range) for ARCAD, DAD 21.27±3.57 mm (11-38 mm in range) for DAD; 23.27±4.03 mm (14-40 mm in range) for MPAD, 17.27±3.19 mm (10-30 mm in range) for RPAD, and 17.62±3.06 mm (10-37 mm in range) for LPAD. Statistically significantly higher values were obtained in all diameters for cases over 40 years of age. Similarly, higher values were obtained in all diameters for males compared to females.
CONCLUSION
The diameters of all thoracic main vascular structures are larger in men than in women and increase with age.
PubMed: 37181064
DOI: 10.14744/nci.2021.03206 -
Radiography (London, England : 1995) May 2022To design a custom phantom of the coronary arteries to optimize CT coronary angiography (CCTA) protocols.
INTRODUCTION
To design a custom phantom of the coronary arteries to optimize CT coronary angiography (CCTA) protocols.
METHODS
Characteristics of the left and right coronary arteries (mean Hounsfield Unit (HU) values and diameters) were collected from consecutive CCTA examinations (n = 43). Four different materials (two mixtures of glycerine, gelatine and water, pig hearts, Ecoflex™ silicone) were scanned inside a Lungman phantom using the CCTA protocol to find the closest model to in vivo data. A 3D printed model of the coronary artery tree was created using CCTA data by exporting a CT volume rendering into Autodesk Meshmixer™ software. The model was placed in an acid bath for 5 h, then covered in Ecoflex™, which was removed after drying. Both the Ecoflex™ and pig heart were later filled with a mixture of contrast (Visipaque 320 mg I/ml), NaCl and gelatin and scanned with different levels of tube current and iterative reconstruction (ASiR-V). Objective (HU, noise and size (vessel diameter) and subjective analysis were performed on all scans.
RESULTS
The gelatine mixtures had HU values of 130 and 129, Ecoflex™ 65 and the pig heart 56. At the different mA/ASiR-V levels the contrast filled Ecoflex™ had a mean HU 318 ± 4, noise 47±7HU and diameter of 4.4 mm. The pig heart had a mean HU of 209 ± 5, noise 38±4HU and a diameter of 4.4 mm. With increasing iterative reconstruction level the visualisation of the pig heart arteries decreased so no measurements could be performed.
CONCLUSION
The use of a 3D printed model of the arteries and casting with the Ecoflex™ silicone is the most suitable solution for a custom-designed phantom.
IMPLICATIONS FOR PRACTICE
Custom designed phantoms using 3D printing technology enable cost effective optimisation of CT protocols.
Topics: Animals; Coronary Vessels; Humans; Printing, Three-Dimensional; Radiation Dosage; Silicones; Swine; Tomography, X-Ray Computed
PubMed: 34556417
DOI: 10.1016/j.radi.2021.09.001 -
Revista Portuguesa de Cardiologia :... Jul 2023Several studies comparing optical coherence tomography (OCT) and intravascular ultrasound (IVUS) have revealed that OCT consistently provides smaller area and diameter...
INTRODUCTION AND OBJECTIVES
Several studies comparing optical coherence tomography (OCT) and intravascular ultrasound (IVUS) have revealed that OCT consistently provides smaller area and diameter measurements. However, comparative assessment in clinical practice is difficult. Three-dimensional (3D) printing offers a unique opportunity to assess intravascular imaging modalities. We aim to compare intravascular imaging modalities using a 3D-printed coronary artery in a realistic simulator and to assess whether OCT underestimates intravascular dimensions, exploring potential corrections.
METHODS
A standard realistic left main anatomy with an ostial left anterior descending artery lesion was replicated using 3D printing. After provisional stenting and optimization, IVI was obtained. Modalities included 20 MHz digital IVUS, 60 MHz rotational IVUS (HD-IVUS) and OCT. We assessed luminal area and diameters at standard locations.
RESULTS
Considering all coregistered measurements, OCT significantly underestimated area, minimal diameter and maximal diameter measurements in comparison to IVUS and HD-IVUS (p<0.001). No significant differences were found between IVUS and HD-IVUS. A significant systematic dimensional error was found in OCT auto-calibration by comparing known reference diameter of guiding catheter (1.8 mm) to measured mean diameter (1.68 mm±0.04 mm). By applying a correction factor based on the reference guiding catheter area to OCT, the luminal areas and diameters were not significantly different compared to IVUS and HD-IVUS.
CONCLUSION
Our findings suggest that automatic spectral calibration method for OCT is inaccurate, with a systematic underestimation of luminal dimensions. When guiding catheter correction is applied the performance of OCT is significantly improved. These results may be clinically relevant and need to be validated.
Topics: Humans; Coronary Artery Disease; Predictive Value of Tests; Ultrasonography, Interventional; Heart; Coronary Vessels; Tomography, Optical Coherence
PubMed: 36893842
DOI: 10.1016/j.repc.2023.03.001 -
Nigerian Journal of Clinical Practice Jun 2022Assessment of intravascular volume status is important in pediatric patients admitted to the emergency departments and pediatric intensive care units. Inferior vena cava...
BACKGROUND
Assessment of intravascular volume status is important in pediatric patients admitted to the emergency departments and pediatric intensive care units. Inferior vena cava (IVC) diameter and collapsibility index are used to evaluate the intravascular volume status in adults. The normal range of IVC diameter is available for adults and the normal range considered for adults is between 1.7 to 2.1 cm, but such normative data is limited for children of all ages.
AIMS
Our aim in this study was to obtain the IVC and the aorta diameter reference values and the mean vena cava collapsibility index in healthy and normovolemic children.
SUBJECTS AND METHODS
Vena cava inferior and aorta images in B mode were obtained. IVC diameter in the inspiratory and the largest IVC diameter in the expiratory were recorded, and the vena cava collapsibility index was calculated.
RESULTS
Ultrasonographic measurements were performed in total on 1938 children. A significant positive correlation was found between IVC and aorta diameters with age. The collapsibility index was found as 37.2% (SD 11.8) in the overall study population. In addition, the reference values for the IVC and aorta diameters obtained from the measurements were also acquired.
CONCLUSIONS
We believe that our IVC and aorta diameter measurements obtained from a large number of participants may be used as reference values in emergency departments and intensive care units.
Topics: Adult; Aorta; Child; Humans; Intensive Care Units; Prospective Studies; Ultrasonography; Vena Cava, Inferior
PubMed: 35708424
DOI: 10.4103/njcp.njcp_1801_21 -
NMR in Biomedicine Apr 2016Mapping axon diameter is of interest for the potential diagnosis and monitoring of various neuronal pathologies. Advanced diffusion-weighted MRI methods have been...
Mapping axon diameter is of interest for the potential diagnosis and monitoring of various neuronal pathologies. Advanced diffusion-weighted MRI methods have been developed to measure mean axon diameters non-invasively, but suffer major drawbacks that prevent their direct translation into clinical practice, such as complex non-linear data fitting and, more importantly, long scanning times that are usually not tolerable for most human subjects. In the current study, temporal diffusion spectroscopy using oscillating diffusion gradients was used to measure mean axon diameters with high sensitivity to small axons in the central nervous system. Axon diameters have been found to be correlated with a novel metric, DDR⊥ (the rate of dispersion of the perpendicular diffusion coefficient with gradient frequency), which is a model-free quantity that does not require complex data analyses and can be obtained from two diffusion coefficient measurements in clinically relevant times with conventional MRI machines. A comprehensive investigation including computer simulations and animal experiments ex vivo showed that measurements of DDR⊥ agree closely with histological data. In humans in vivo, DDR⊥ was also found to correlate well with reported mean axon diameters in human corpus callosum, and the total scan time was only about 8 min. In conclusion, DDR⊥ may have potential to serve as a fast, simple and model-free approach to map the mean axon diameter of white matter in clinics for assessing axon diameter changes.
Topics: Adult; Animals; Axons; Diffusion Magnetic Resonance Imaging; Female; Humans; Male; Rats, Sprague-Dawley; Time Factors
PubMed: 27077155
DOI: 10.1002/nbm.3484 -
Acta Ophthalmologica May 2021To investigate changes in retinal oximetry and the diameter of retinal vasculature in patients with chronic kidney disease (CKD) and relationships between retinal...
PURPOSE
To investigate changes in retinal oximetry and the diameter of retinal vasculature in patients with chronic kidney disease (CKD) and relationships between retinal vasculature and the estimated glomerular filtration rate (eGFR), provide a scientific basis for the early detection and diagnosis of CKD.
METHODS
Eighty-three patients with CKD and 103 healthy individuals were included after providing informed consent. All participants were examined using a noninvasive technology (Oxymap Inc., Reykjavik, Iceland) for measuring the arterial (SaO ) and venous (SvO ) oxygen saturation and the arteriovenous difference in oxygen saturation (Sa-vO ). The corresponding retinal vessel diameters of these arterioles (D-A) and venules (D-V) were measured. The eGFR of patients with CKD was calculated from the serum creatinine concentration.
RESULTS
In general, patients with CKD had higher mean SaO values than healthy individuals (100.15 ± 4.68% versus 97.14 ± 4.22%; p < 0.001, mean ± SD). The mean SaO in the superior temporal, superior nasal and inferior nasal quadrants significantly increased. There was no significant difference measured in the SvO when patients with CKD (63.66 ± 5.29%) and healthy individuals (62.70 ± 5.27%) were compared. The mean Sa-vO of the CKD group (36.49 ± 4.98%) was increased compared with normal subjects (34.44 ± 4.76%) (p = 0.005). The retinal arteriole diameter was narrower in patients with CKD than in normal individuals (117.53 ± 14.88 μm versus 126.87 ± 14.98 μm; p < 0.001, mean ± SD), and the arteriovenous ratio was smaller than in normal individuals (0.71 ± 0.09 versus 0.77 ± 0.09; p < 0.001, mean ± SD). Pearson's two-tailed correlation showed a significant correlation between the SaO and eGFR (R = -0.363, p = 0.001), and narrower retinal arterial calibre was significantly associated with a lower eGFR (R = 0.415, p < 0.001).
CONCLUSION
Based on our results, there were alterations in retinal oxygen saturation and vascular diameter in patients with CKD. Further studies are needed to determine whether such changes play a role in the development of CKD.
Topics: Adult; Case-Control Studies; Female; Glomerular Filtration Rate; Humans; Male; Middle Aged; Oxygen; Oxygen Consumption; Prospective Studies; Regional Blood Flow; Renal Insufficiency, Chronic; Retinal Vessels
PubMed: 32529722
DOI: 10.1111/aos.14398 -
Philosophical Transactions. Series A,... Feb 2018There is an emerging consensus that higher plants synthesize cellulose microfibrils that initially comprise 18 chains. However, the mean number of chains per microfibril... (Review)
Review
There is an emerging consensus that higher plants synthesize cellulose microfibrils that initially comprise 18 chains. However, the mean number of chains per microfibril is usually greater than 18, sometimes much greater. Microfibrils from woody tissues of conifers, grasses and dicotyledonous plants, and from organs like cotton hairs, all differ in detailed structure and mean diameter. Diameters increase further when aggregated microfibrils are isolated. Because surface chains differ, the tensile properties of the cellulose may be augmented by increasing microfibril diameter. Association of microfibrils with anionic polysaccharides in primary cell walls and mucilages leads to mechanisms of disaggregation that may be relevant to the preparation of nanofibrillar cellulose products. For the preparation of nanocrystalline celluloses, the key issue is the nature and axial spacing of disordered domains at which axial scission can be initiated. These disordered domains do not, as has often been suggested, take the form of large blocks occupying much of the length of the microfibril. They are more likely to be located at chain ends or at places where the microfibril has been mechanically damaged, but their structure and the reasons for their sensitivity to acid hydrolysis need better characterization.This article is part of a discussion meeting issue 'New horizons for cellulose nanotechnology'.
PubMed: 29277742
DOI: 10.1098/rsta.2017.0045 -
Turk Gogus Kalp Damar Cerrahisi Dergisi Jan 2020This study aims to define normal coronary artery diameters of males and females in a sample of Turkish population, compared to Asian-Indian and Western Caucasian...
BACKGROUND
This study aims to define normal coronary artery diameters of males and females in a sample of Turkish population, compared to Asian-Indian and Western Caucasian populations.
METHODS
Angiographic and demographic data of a total of 324 patients (147 males, 177 females; mean age 55.3±10.1 years; range, 32 to 82 years) who underwent elective coronary angiography with angiographically normal coronary arteries between July 2017 and March 2019 were analyzed retrospectively. Proximal diameters of major epicardial coronary arteries were measured using the Axiom Artis software according to edge detection method. All the measurements were adjusted to the body surface area. Unadjusted and adjusted values were compared between genders and with the Asian-Indian and Caucasian population samples.
RESULTS
The mean diameters of unadjusted/adjusted left main coronary artery, proximal left anterior descending artery, proximal left circumflex artery, and proximal right coronary artery were 4.5±0.6 mm/2.4±0.4 mm/m, 3.7±0.5 mm/1.9±0.3 mm/m, 3.3±0.6 mm/1.7±0.3 mm/m, and 3.4±0.6 mm/1.8±0.4 mm/m, respectively. Adjusted left main coronary artery and proximal left circumflex artery were narrower, and unadjusted proximal left anterior descending artery and unadjusted/adjusted proximal right coronary artery were larger in men, compared to women in the Turkish population. Turkish population had similar body surface area and unadjusted/adjusted coronary diameters with Caucasians, whereas adjusted proximal left anterior descending artery was larger in the Turkish population than in Asian-Indians.
CONCLUSION
Our study findings on the Turkish population contradict the traditional belief that women have narrower coronary arteries then men. Furthermore, the Turkish population have comparable adjusted/unadjusted coronary diameters with the Western Caucasians, but larger adjusted/unadjusted proximal left anterior descending artery, compared to Asian-Indians. We believe that our findings may contribute to the global data pool of normal coronary diameters and can be utilized in future studies as a database.
PubMed: 32175150
DOI: 10.5606/tgkdc.dergisi.2020.18475 -
Folia Morphologica 2016The coronary sinus is the main cardiac vein and it has become a clinically important structure especially through its role in providing access for different cardiac...
BACKGROUND
The coronary sinus is the main cardiac vein and it has become a clinically important structure especially through its role in providing access for different cardiac procedures.
MATERIALS AND METHODS
The study was carried out on 100 randomly selected adult human cadaver hearts fixed in 10% formalin. The transverse and craniocaudal diameters of the coronary sinus ostium (CSO) were directly measured. The presence of the Thebesian valve was noted and the anatomical details of the valve were documented in each case in terms of the shape and extent of coverage of the CSO.
RESULTS
Considerable variations in the diameter of the CSO were observed. The mean craniocaudal diameter of the CSO was 8.1 ± 1.51 mm, and the mean transverse diameter was 7.67 ± 1.72 mm. Heart specimens without Thebesian valve tended to have larger ostia. The mean craniocaudal diameter and the mean transverse diameter of the CSO were statistically larger in the specimens without Thebesian valves (p = 0.000 and p = 0.001, respectively).
CONCLUSIONS
The Thebesian valves were observed in 86 hearts, and a wide variety of their morphology was seen. The majority of the Thebesian valves were semilunar in shape (74.42%). The extent to which the valve covered the ostium was variable, including remnant valves that covered < 15% of the CSO (35%), and valves that were large and covered at least 75% of the CSO (22.09%). In 3 specimens the valve completely occluded the ostium.
Topics: Cadaver; Coronary Sinus; Coronary Vessels; Heart Valves; Humans
PubMed: 26431050
DOI: 10.5603/FM.a2015.0089