scholarly journals Effects of Different Methods of Air Disinfection of Computed Tomography Rooms Dedicated to COVID-19 Cases

2020 ◽  
Vol 2020 ◽  
pp. 1-5 ◽  
Author(s):  
Yilian Cheng ◽  
Jing Hu ◽  
Hui Chen ◽  
Liu Wu ◽  
Jianmei Liao ◽  
...  

Objective. To monitor the number of bacterial colonies in the air of computed tomography (CT) room for COVID-19 using different disinfection methods and to identify the most effective method for disinfection and protection of equipment. Methods. Three methods for disinfection using ultraviolet germicidal irradiation (group A), plasma circulation air sterilizer (group B), and ultraviolet germicidal irradiation plus plasma circulation air sterilizer (group C) were utilized to sanitize the air in the CT room dedicated to COVID-19 cases. Single-factor ANOVA was used to evaluate and compare the disinfection effect of the three air disinfection methods; an air microbial sampler was used to sample and measure the number of bacteria in the air of the machine room. Results. The number of bacteria in the air immediately after disinfection was significantly lower than before disinfection ( p < 0.01 ). All three disinfection methods met the disinfection requirement. No significant differences in the number of air bacteria in the machine room immediately after disinfection were observed among the three methods ( p > 0.05 ). In addition, the effect of disinfection after 2 h was compared, and the number of bacteria in group C after 2 h was significantly lower than that in group A and group B. Conclusions. All three disinfection methods have significant disinfection effects. In addition, using ultraviolet disinfection lamps combined with a plasma air disinfection machine to sterilize the air in CT machine room has the best disinfection effect for the longest duration. Therefore, we recommend the combined disinfection method (ultraviolet disinfection lamps plus plasma air disinfection), as well as formulating relevant disinfection management norms, which should thus be the method to use during pandemics.

Author(s):  
Pouran Samimi ◽  
Sara Kaveh ◽  
Maryam Khoroushi

Objectives: Photopolymerization immediately sets dual-cure cements and prevents the continuation of chemical polymerization. Delayed light-curing allows the chemical process to continue up to the point before starting irradiation; however, there is a controversy in this respect. The present study evaluates the effect of delayed light-curing through a zirconia disc on the microhardness and fracture toughness (KIC) of two types of dual-cure cement. Materials and Methods: Samples measuring 25×5×3 mm3 were prepared for fracture toughness test, and discs measuring 5 mm in diameter and 3 mm in thickness were prepared for microhardness test using Bifix and BisCem cements. Light-curing protocols were as follows: immediate light-curing (group A), a 2-minute delay (group B), a 5-minute delay (group C), direct irradiation (group D), and no irradiation (group E). In groups A to C, light-curing was carried out through a zirconia disc. Data were analyzed by two-way and one-way analysis of variance (ANOVA), post-hoc Tukey's test, and Kruskal-Wallis test at 95% confidence interval. Results: There was a significant difference in the microhardness of the cements (P=0.00). Delayed light-curing had no effect on microhardness (P=0.080). The microhardness of BisCem in group E was significantly lower than that in group D (P=0.015). The fracture toughness of Bifix in groups B and C was significantly different than that in group E and BisCem groups. Conclusions: Under the limitations of our study, delayed light-curing had different effects on microhardness and fracture toughness. Differences in light-curing protocols resulted in different effects based on the cement type. Light-curing is recommended to achieve optimal mechanical properties.


2021 ◽  
pp. 000313482110474
Author(s):  
Tarik Wasfie ◽  
Daniel Rivera ◽  
Mursal Naisan ◽  
Shelby Zaremba ◽  
Mikayla Depuydt ◽  
...  

Introduction Computed tomography scans became the mainstay of emergency department (ED) evaluation of trauma patients including those with a high Glasgow Coma Scale (GCS) and a low Injury Severity Score (ISS). We elected to find the value of abdominal and pelvic CT in patients with negative physical examination and Focused Assessment of Sonography for Trauma (FAST) on arrival to the ED. Methods This study is a retrospective analysis of 901 consecutive patients from 2017 to 2019 who presented to the ED with level 2 and 3 activation criteria. Each patient received a physical examination, CT abdomen and pelvis, and FAST exam. Data were collected on external factor including GCS, ISS, age, sex, comorbidities, anticoagulation use, and surgical intervention. The patients were divided into 2 groups, Group A and B. Group A consisted of patients with a negative physical exam, FAST, and CT result. Group B included patients with a negative physical exam and FAST exam with positive CT findings. Statistical analysis was done using a Student’s t-test and chi-square test for significance value of P < .05. Institutional Review Board approval was obtained for this study. Results A total of 901 patients were analyzed which included 489 (54.3%) male and 412 (45.7%) female with a mean age of 56.2 (SD = 22.62) years. Out of the 901 patients, 461 patients received a physical, FAST, and CT exam. Group A consisted of 442 (95.9%) patients and Group B had 19 (4.1%) patients. Both groups were similar in GCS and ISS scoring with no significance difference in age, sex, comorbidities, and anticoagulation use. There was a significant difference in the ICU and hospital mean length of stay when CT scan was positive [2 (SD = 4.23) days vs. .6 (SD = 1.33) days with P < .0001 and 4.57 (SD ± 4.17) days vs. 2.5 (SD = 2.00) days with P < .0001, respectively]. The CT findings of the 19 patients in group B consisted of 6 incidentalomas, 5 vertebral compression fractures, 4 pelvic bone fractures, 1 minor liver contusion, 1 non-specific bowel thickening, 1 non-displaced rib fracture, and 1 case of small amount of free fluid in the pelvis. None of the CT findings required surgical intervention. Conclusion Computed tomography of the abdomen and pelvis in trauma patients with high GCS and low ISS with initial negative physical and FAST examination did not provide additional critical information.


2019 ◽  
Vol 61 (1) ◽  
Author(s):  
Christin Röttiger ◽  
Maren Hellige ◽  
Bernhard Ohnesorge ◽  
Astrid Bienert-Zeit

Abstract Background The use of cadavers for radiology research methodologies involving subjective image quality evaluation of anatomical criteria is well-documented. The purpose of this method comparison study was to evaluate the image quality of dental and adjacent structures in computed tomography (CT) and high-field (3 T) magnetic resonance (MR) images in cadaveric heads, based on an objective four-point rating scale. Whilst CT is a well-established technique, MR imaging (MRI) is rarely used for equine dental diagnostics. The use of a grading system in this study allowed an objective assessment of CT and MRI advantages in portraying equine cheek teeth. As imaging is commonly performed with cadaveric or frozen and thawed heads for dental research investigations, the second objective was to quantify the impact of the specimens’ conditions (in vivo, post-mortem, frozen-thawed) on the image quality in CT and MRI. Results The CT and MR images of nine horses, focused on the maxillary premolar 08s and molar 09s, were acquired post-mortem (Group A). Three observers scored the dental and adjacent tissues. Results showed that MR sequences gave an excellent depiction of endo- and periodontal structures, whereas CT produced high-quality images of the hard tooth and bony tissues. Additional CT and MRI was performed in vivo (Group B) and frozen-thawed (Group C) in three of these nine horses to specify the condition of the best specimens for further research. Assessing the impact of the specimens’ conditions on image quality, specific soft tissues of the maxillary 08s and 09s including adjacent structures (pulps, mucosa of the maxillary sinuses, periodontal ligament, soft tissue inside the infraorbital canal) were graded in group B and C and analysed for significant differences within CT and MR modalities in comparison to group A. Results showed that MRI scores in vivo were superior to the post-mortem and frozen-thawed condition. Conclusions On comparing the imaging performance of CT and MRI, both techniques show a huge potential for application in equine dentistry. Further studies are needed to assess the clinical suitability of MRI. For further research investigations it must be considered, that the best MR image quality is provided in live horses.


2020 ◽  
Vol 30 (5) ◽  
pp. 666-670
Author(s):  
Ilaria Chirichilli ◽  
Francesco Giosuè Irace ◽  
Luca Paolo Weltert ◽  
Andrea Salica ◽  
Lorenzo Guerrieri Wolf ◽  
...  

Abstract OBJECTIVES The shape of the aortic annulus is still under debate. Recent findings suggest a possible gradual spectrum of circularity from tricuspid aortic valves (TAVs), to type 1 bicuspid aortic valves (BAVs) to type 0 BAVs. BAVs have been recently classified in a symmetrical (type A), asymmetrical (type B) or very asymmetrical (type C) phenotype according to the commissural orientation (CO) (160°–180°, 140°–159° and 120°–139°, respectively). The aim of this study is to verify in BAVs the correlation between the aortic annular shape and the CO of valve cusps and to suggest a new anatomical and geometric classification of BAVs based on CO and annular shape. METHODS We retrospectively selected 191 consecutive patients who underwent both electrocardiography-gated computed tomography scan of the aortic root and transthoracic echocardiography between January 2016 and June 2019. The population was divided into 2 groups: 54 BAVs and 137 TAVs. We analysed the subgroup of BAV patients and divided them into group A, group B and group C depending on the CO. The shape of the aortic annulus was considered ‘circular’ or ‘elliptic’ according to the ellipticity index (EI).We studied the possible correlation between CO and annular shape in BAVs. We also analysed the subgroup of TAV patients studying their annular shape and EI. RESULTS After univariate linear regression, BAV patients showed a significant correlation between the CO and the EI (R = −0, 445, R2 = 0, 198, P = 0.001). As the CO decreases, the EI increases and approaches an elliptical shape. After grouping BAVs according to the CO, a mean EI of 1.10 ± 0.07 was found in group A, 1.13 ± 0.08 in group B, 1.18 ± 0.07 in group C, P = 0.0097 indicating a gradual spectrum of ellipticity with the decrease of CO. TAVs subgroup showed a mean EI of 1.27 ± 0.09, suggesting that the more the CO is reduced in BAVs, the more the annulus probably tends towards the very elliptical shape of TAVs. CONCLUSIONS This study shows a linear correlation between CO and annular shape in BAVs. In particular, the aortic annulus follows a continuous spectrum of ellipticity depending on the CO. These findings lay the groundwork for a new anatomical classification of BAVs based on CO and annular shape.


2015 ◽  
Vol 48 (5) ◽  
pp. 292-297 ◽  
Author(s):  
Ricardo Francisco Tavares Romano ◽  
Priscila Silveira Salvadori ◽  
Lucas Rios Torres ◽  
Elisa Almeida Sathler Bretas ◽  
Daniel Bekhor ◽  
...  

AbstractObjective:To assess the reduction of estimated radiation dose in abdominal computed tomography following the implementation of new scan protocols on the basis of clinical suspicion and of adjusted images acquisition parameters.Materials and Methods:Retrospective and prospective review of reports on radiation dose from abdominal CT scans performed three months before (group A – 551 studies) and three months after (group B – 788 studies) implementation of new scan protocols proposed as a function of clinical indications. Also, the images acquisition parameters were adjusted to reduce the radiation dose at each scan phase. The groups were compared for mean number of acquisition phases, mean CTDIvol per phase, mean DLP per phase, and mean DLP per scan.Results:A significant reduction was observed for group B as regards all the analyzed aspects, as follows: 33.9%, 25.0%, 27.0% and 52.5%, respectively for number of acquisition phases, CTDIvol per phase, DLP per phase and DLP per scan (p < 0.001).Conclusion:The rational use of abdominal computed tomography scan phases based on the clinical suspicion in conjunction with the adjusted images acquisition parameters allows for a 50% reduction in the radiation dose from abdominal computed tomography scans.


2008 ◽  
Vol 49 (9) ◽  
pp. 1068-1078 ◽  
Author(s):  
N. Takeyama ◽  
Y. Ohgiya ◽  
H. Itokawa ◽  
Y. Takahashi ◽  
M. Obuchi ◽  
...  

Background: Although fast acquisition of multidetector-row computed tomography (MDCT) can make it possible to acquire sufficient early vascular enhancement using small volumes and high concentrations of contrast material (CM), there are still some problems with nephrotoxicity and costs related to CM. Purpose: To compare the qualitative and quantitative performance in cervicocranial CT angiography (CTA) using two different iodine volumes and concentrations of CM. Material and Methods: CTA ranging from the aortic arch (AA) to distal to the circle of Willis (cW) was performed on a 32-MDCT system. Fifty-eight patients were randomly divided into two groups: group A (29 patients) received 60 ml of 300 mg I/ml CM, and group B (the other 29 patients) received 40 ml of 370 mg I/ml CM. Time to peak arterial enhancement at cW (Tc) was calculated. As scan speed was 96.9 mm/s and injection rate was 4.0 ml/s, scanning delay was individually decided according to Tc and scan duration between AA and cW. Arterial attenuation along the z-axis at eight points in the carotid-cerebral artery and venous attenuation of the internal jugular vein (IJV) at carotid bifurcation were measured. Mean attenuation values were then quantitatively analyzed. Postprocessing images were qualitatively assessed. Results: Arterial attenuation profiles revealed maximum attenuation at the distal common carotid artery in both groups. Although there were no significant differences in mean arterial attenuation in group A versus group B (402±70 HU vs. 407±67 HU; P=0.78), venous attenuation of the IJV was lower in group B than in group A (114±57 HU vs. 224±81 HU; P<0.001). Although arterial images demonstrated no difference qualitatively between the two groups, the venous contamination of IVC was less prominent in group B. Conclusion: Although a different amount of CM was administered in both groups, quantitative and qualitative arterial images did not show significant differences between the two groups.


Author(s):  
Fabio De-Giorgio ◽  
Vincenzo M. Grassi ◽  
Eva Bergamin ◽  
Alessandro Cina ◽  
Franca Del Del Nonno ◽  
...  

There is still a lack of knowledge concerning the pathophysiology of death among COVID-19-deceased patients, and the question of whether a patient has died with or due to COVID-19 is still very much debated. In Italy, all deaths of patients who tested positive for SARS-CoV-2 are defined as COVID-19-related, without considering pre-existing diseases that may either contribute to or even cause death. Our study included nine subjects from two different nursing homes (Cases 1–4, Group A; Cases 5–9, Group B). The latter included patients who presumably died from CO poisoning due to a heating system malfunction. All subjects tested positive for COVID-19 both ante- and post-mortem and were examined using post-mortem computed tomography prior to autopsy. COVID-19 was determined to be a contributing cause in the deaths of four out of nine subjects (death due to COVID-19; i.e., pneumonia and sudden cardiac death). In the other five cases, for which CO poisoning was identified as the cause of death, the infection presumably had no role in exitus (death with COVID-19). In our attempt to classify our patients as dying with or due to COVID-19, we found the use of complete assessments (both histological analyses and computed tomography examination) fundamental.


2021 ◽  
Author(s):  
Jinming Shi ◽  
Yuan Tang ◽  
Ning Li ◽  
Yongwen Song ◽  
Shulian Wang ◽  
...  

Abstract BackgroundRespiratory motion may introduce errors during radiotherapy. This study aims to assess and validate internal gross tumour volume (IGTV) margins in different regions in gastroesophageal junction (GEJ) tumours during simultaneous integrated boost radiotherapy.MethodsWe enrolled 10 patients in group A and 9 patients in group B. For all patients, two markers were placed at the upper and lower boundaries of tumour before treatment. In group A, within the simulation and every five fractions of radiotherapy, we used 4-dimensional computed tomography (4DCT) to record the intrafractional displacement of the proximal and distal markers. By fusing the average image of each fraction with the simulation image according to the lumbar vertebra, the interfractional displacement could be obtained. We calculated the IGTV margin in the proximal and distal regions of the GEJ tumour. In group B, by referring to the simulation images and cone-beam computed tomography (CBCT) images, the range of tumour displacement in different regions within the GEJ tumour was estimated. We verified the proportion of tumours with marker displacement within the range obtained in group A to estimate the accuracy of the IGTV margin.ResultsThe intrafractional displacement in the cranio-caudal (CC) direction was significantly larger than that in the anterior-posterior (AP) and left-right (LR) directions for both the proximal and distal markers of the tumour. The interfractional displacement in the AP and LR directions was larger than that in the CC direction (p=0.001, p=0.017) according to the distal marker. The IGTV margins for in the LR, AP and CC directions were 9 mm, 8.5 mm and 12.1 mm for proximal marker and 15.8 mm, 12.7 mm and 11.5 mm for distal marker. In group B, the proportions of tumours that fell within the IGTV margin in the LR, AP and CC directions were 96.5%, 91.3% and 96.5% for the proximal marker and 100%, 96.5%, 93.1% for the distal marker.ConclusionsOur study proposed individualized IGTV margins for different regions within GEJ tumours during neoadjuvant radiotherapy. The IGTV margin determined in this study was relatively small and was validated appropriately. It could be a reference in clinical practice.


2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Yuanjun Qi ◽  
Jianbin Li ◽  
Yingjie Zhang ◽  
Qian Shao ◽  
Xijun Liu ◽  
...  

Abstract Background This study aimed to investigate the effect of abdominal compression on tumour motion and target volume and to determine suitable planning target volume (PTV) margins for patients treated with lung stereotactic body radiotherapy (SBRT) based on four-dimensional computed tomography (4DCT). Methods Twenty-three patients diagnosed to have a peripheral pulmonary tumour were selected and divided into an all lesions group (group A), an upper middle lobe lesions group (group B), and a lower lobe lesions group (group C). Two 4DCT scans were performed in each patient, one with and one without abdominal compression. Cone beam computed tomography (CBCT) was performed before starting treatment. The gross target volumes (GTVs) were delineated and internal gross target volumes (IGTVs) were defined. IGTVs were generated using two methods: (1) the maximum intensity projections (MIPs) based on the 4DCT were reconstructed to form a single volume and defined as the IGTVMIP and (2) GTVs from all 10 phases were combined to form a single volume and defined as the IGTV10. A 5-mm, 4-mm, and 3-mm margin was added in all directions on the IGTVMIP and the volume was constructed as PTVMIP5mm, PTVMIP4mm, and PTVMIP3mm. Results There was no significant difference in the amplitude of tumour motion in the left–right, anterior–posterior, or superior-inferior direction according to whether or not abdominal compression was applied (group A, p = 0.43, 0.27, and 0.29, respectively; group B, p = 0.46, 0.15, and 0.45; group C, p = 0.79, 0.86, and 0.37; Wilcoxon test). However, the median IGTVMIP without abdominal compression was 33.67% higher than that with compression (p = 0.00), and the median IGTV10 without compression was 16.08% higher than that with compression (p = 0.00). The median proportion of the degree of inclusion of the IGTVCBCT in PTVMIP5mm, PTVMIP4mm, and PTVMIP3mm ≥ 95% was 100%, 100%, and 83.33%, respectively. Conclusions Abdominal compression was useful for reducing the size of the IGTVMIP and IGTV10 and for decreasing the PTV margins based on 4DCT. In IGTVMIP with abdominal compression, adding a 4-mm margin to account for respiration is feasible in SBRT based on 4DCT.


1999 ◽  
Vol 86 (2) ◽  
pp. 701-708 ◽  
Author(s):  
Claudius Gückel ◽  
Athol U. Wells ◽  
David A. Taylor ◽  
François Chabat ◽  
David M. Hansell

The purpose of this study was to investigate whether hypoxic pulmonary vasoconstriction is the major determinant of the computed tomography (CT) pattern of mosaic attenuation in asthmatic patients with induced bronchoconstriction. Thin-section CT was performed at suspended full inspiration immediately and 30 min after methacholine bronchoprovocation in 22 asthmatic subjects, who were randomly assigned to breathe room air ( group A, n = 8), oxygen via nasal prongs at 5 l/min ( group B, n = 8), and oxygen via face mask at 12 l/min ( group C, n = 6). CT changes were quantified in terms of global lung density and density in hypodense and hyperdense areas. Lung parenchymal density increases were greatest in group C and greater in group B than in group A, globally ( P = 0.03) and in hypodense regions ( P = 0.01). On bivariate analysis, the only change in cross-sectional area was related to change in global density. In hypodense regions, density change was related both to reduction in cross-sectional area ( P < 0.0005) and to oxygen administration ( P = 0.01). After correction for changes in global lung density, only oxygen was independently related to density increase in hypodense areas ( P = 0.02). In induced bronchoconstriction, the CT appearance of mosaic attenuation can be largely ascribed to hypoxic vasoconstriction rather than to changes in lung inflation.


Sign in / Sign up

Export Citation Format

Share Document