Computerized tomography: taking sectional x rays

Physics Today ◽  
1977 ◽  
Vol 30 (12) ◽  
pp. 32-41 ◽  
Author(s):  
William Swindell ◽  
Harrison H. Barrett
1987 ◽  
Vol 2 (02) ◽  
pp. 148-154 ◽  
Author(s):  
A.O. Hove ◽  
J.K. Ringen ◽  
P.A. Read

2001 ◽  
Vol 31 (5) ◽  
pp. 377-382 ◽  
Author(s):  
Samya Z. Nasr ◽  
Lawrence R. Kuhns ◽  
Randall W. Brown ◽  
Martin E. Hurwitz ◽  
Georgiana M. Sanders ◽  
...  

Author(s):  
Mukul Singh ◽  
Shrey Bansal ◽  
Sakshi Ahuja ◽  
Rahul Kumar Dubey ◽  
Bijaya Ketan Panigrahi ◽  
...  

Abstract The novel discovered disease coronavirus popularly known as COVID19 is a lung infection disease that causes adverse effects on the human respiratory system. It is caused due to Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) and declared a pandemic by the World Health Organization (WHO). For COVID-19 detection, chest radiography, i.e., computerized tomography(CT) scan, X-rays, etc. are widely investigated. In the proposed work, a deep learning model, i.e., truncated VGG16(Visual Geometry Group from Oxford) is implemented to screen COVID-19 CT scans. The VGG16 architecture is fine-tuned and used to extract features from CT Scan images. Further Principal Component Analysis (PCA) is used for feature selection. The final classification is performed using four different classifiers, namely deep convolutional neural network(CNN) , Extreme Learning Machine (ELM), Online sequential ELM, and Bagging Ensemble with support vector machine (SVM) . The best performing classifier Bagging Ensemble with SVM within 385 ms achieved an accuracy of 95.7%, precision of 95.8%, Area Under Curve (AUC) of 0.958, and an F1 score of 95.3% on 208 test images. The results obtained on diverse datasets prove the superiority and robustness of the proposed work in comparison to the techniques available in the literature.


2017 ◽  
Vol 45 ◽  
pp. 5
Author(s):  
Claudine Botelho De Abreu ◽  
Lívia De Paula Coelho ◽  
Rodrigo Bernardes Nogueira ◽  
Nathália Brant Malta Salgueiro ◽  
Antônio Carlos Cunha Lacreta Junior ◽  
...  

Background: Pyothorax is characterized by the accumulation of septic purulent fluid within the pleural space. Most of the times, it is the true identified infection way in only 2 to 22% of dog cases. Reports show that the most common cause is the migration of grass edges and plant materials, mainly in regions of California, USA. The current study reports an unusual case of a Cassia fistula pod (Brazilian Acácia Imperial), of around 10x3 cm long, causing chronic Pyothorax in a Border Collie female dog.Case: It was admitted in a Teaching Veterinary Hospital a 2-year-old female Border Collie, weighing 16.5 kg. The complaint was producing of severe cough, dyspnoea, hyporexia and loss of weight in the past three months. The animal could have been horse-kicked, as it is used to herding. In the physical examination, it was detected bilateral thick lung crepitations, more evident in the ventral skull area, dyspnoea, tachypnea, fever, splenomegaly and low body condition score (3/9). The laboratory tests revealed nonregenerative anemia and leukemoid reaction. The chest x-ray showed intense pulmonary opacification and free fluids in the pleural space along with a heterogenic cylindrical image of the mixed radiopacity. This image was then confirmed as the intrathoracic foreing body by the use of a computerized tomography. In this exam it was also possible to observe the damage of part of the middle and inferior right lung lobe. The cytology of the pleural effusion found mixed inflammation and coccoid bacteria, and the microbiological culture Streptococcus sp., and Escherichia coli. The dog underwent thoracotomy in order to remove the foreign body, which was later identified as being a Cassia fistula pod (Brazilian Acácia Imperial), of around 10x3 cm long. Due to the intense lung damage, a right pneumonectomy was required. After 30 days the animal was fully recovered.Discussion: The applied surgical procedure ended up being the most correct, due to the shape and place of the foreign body, and also due to the massive damage of the lobes on the right lung. In dogs, right pneumonectomy may cause respiratory acidosis and exercise intolerance, besides it can also show signs of hyperinflation in some pulmonary spots. However, such abnormalities were not perceived by the patient. There are a few reports concerning the right pneumonectomy applicability on veterinary routine, nevertheless, it is a perfect practicable intervention from the clinic-surgical perspective, according to this case’s reports. Initially, the possibility of a foreign body was not expected, once the history of a plausible trauma, caused by horse-kick, associated to the presence of thoracic effusion, influenced only to the Pyothorax’s etiology. But the continuity of the clinic condition and the cylindrical image in subsequent x-rays favored the suspect of an foreign body, which could be confirmed in the computerized tomography. However, the way the pod got into the animal’s thorax, adhering to the lung parenchyma, remained undetermined. Besides, there were not found clinic descriptions relating the Cassia fistula pod (Brazilian Acácia Imperial) as an etiological agent of intra-thoracic foreign body in dogs, making this report an unusual clinic case. The computerized tomography was primordial to the definite diagnostic and for choosing the type of surgical procedure to be applied. The right pneumonectomy associated to the removal of the foreign body promoted the success of the treatment without further post-operatory complications.


PEDIATRICS ◽  
1977 ◽  
Vol 59 (2) ◽  
pp. 147-149
Author(s):  
H. V. Fineberg

Computerized tomography (CT) is a remarkable technological triumph whose significance has been likened to the development of the X-ray itself. The CT scanner projects a narrow beam of X-rays across the head or body and uses a computer to convert sequential readings of tissue X-ray absorption into a cross-sectional view of the anatomical part examined. A CT scan entails radiation doses which are comparable to those from conventional X-ray studies, but is capable of distinguishing smaller differences in tissue radio-density. The only significant operational disadvantage to CT is the need for the subject to remain motionless during the time required for the scan, which often necessitates sedation or general anesthesia in restless children and infants.


2013 ◽  
Vol 46 (4) ◽  
pp. 933-938 ◽  
Author(s):  
Zdenko Zápražný ◽  
Dušan Korytár ◽  
Petr Mikulík ◽  
Vladimír Áč

Free-space-propagation-based imaging belongs to several techniques for achieving phase contrast in the hard X-ray range. The basic precondition is to use an X-ray beam with a high degree of coherence. Although the best sources of coherent X-rays are synchrotrons, spatially coherent X-rays emitted from a sufficiently small spot of laboratory microfocus or sub-microfocus sources allow the transfer of some of the modern imaging techniques from synchrotrons to laboratories. Spatially coherent X-rays traverse a sample leading to a phase shift. Beam deflection induced by the local change of refractive index may be expressed as a dark–bright contrast on the edges of the object in an X-ray projection. This phenomenon of edge enhancement leads to an increase in spatial resolution of X-ray projections but may also lead to unpleasant artefacts in computerized tomography unless phase and absorption contributions are separated. The possibilities of processing X-ray images of lightweight objects containing phase contrast using phase-retrieval methods in laboratory conditions are tested and the results obtained are presented. For this purpose, simulated and recorded X-ray projections taken from a laboratory imaging system with a microfocus X-ray source and a high-resolution CCD camera were processed and a qualitative comparison of results was made.


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