Publications by authors named "A B Elizarov"

31 Publications

A simplified cluster model and a tool adapted for collaborative labeling of lung cancer CT scans.

Comput Methods Programs Biomed 2021 Apr 18;206:106111. Epub 2021 Apr 18.

Research and Practical Clinical Center for Diagnostics and Telemedicine Technologies of the Moscow Health Care Department, Petrovka str., 24, Moscow, 127051, Russia; Federal Research Center "Computer Science and Control" of Russian Academy of Sciences, Vavilova str., 44/2, Moscow, 119333, Russia. Electronic address:

Background And Objective: Lung cancer is the most common type of cancer with a high mortality rate. Early detection using medical imaging is critically important for the long-term survival of the patients. Computer-aided diagnosis (CAD) tools can potentially reduce the number of incorrect interpretations of medical image data by radiologists. Datasets with adequate sample size, annotation, and truth are the dominant factors in developing and training effective CAD algorithms. The objective of this study was to produce a practical approach and a tool for the creation of medical image datasets.

Methods: The proposed model uses the modified maximum transverse diameter approach to mark a putative lung nodule. The modification involves the possibility to use a set of overlapping spheres of appropriate size to approximate the shape of the nodule. The algorithm embedded in the model also groups the marks made by different readers for the same lesion. We used the data of 536 randomly selected patients of Moscow outpatient clinics to create a dataset of standard-dose chest computed tomography (CT) scans utilizing the double-reading approach with arbitration. Six volunteer radiologists independently produced a report for each scan using the proposed model with the main focus on the detection of lesions with sizes ranging from 3 to 30 mm. After this, an arbitrator reviewed their marks and annotations.

Results: The maximum transverse diameter approach outperformed the alternative methods (3D box, ellipsoid, and complete outline construction) in a study of 10,000 computer-generated tumor models of different shapes in terms of accuracy and speed of nodule shape approximation. The markup and annotation of the CTLungCa-500 dataset revealed 72 studies containing no lung nodules. The remaining 464 CT scans contained 3151 lesions marked by at least one radiologist: 56%, 14%, and 29% of the lesions were malignant, benign, and non-nodular, respectively. 2887 lesions have the target size of 3-30 mm. Only 70 nodules were uniformly identified by all the six readers. An increase in the number of independent readers providing CT scans interpretations led to an accuracy increase associated with a decrease in agreement. The dataset markup process took three working weeks.

Conclusions: The developed cluster model simplifies the collaborative and crowdsourced creation of image repositories and makes it time-efficient. Our proof-of-concept dataset provides a valuable source of annotated medical imaging data for training CAD algorithms aimed at early detection of lung nodules. The tool and the dataset are publicly available at https://github.com/Center-of-Diagnostics-and-Telemedicine/FAnTom.git and https://mosmed.ai/en/datasets/ct_lungcancer_500/, respectively.
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http://dx.doi.org/10.1016/j.cmpb.2021.106111DOI Listing
April 2021

Membrane-Introduction Mass Spectrometry Analysis of Desflurane, Propofol and Fentanyl in Plasma and Cerebrospinal Fluid for Estimation BBB Properties.

Exp Neurobiol 2015 Sep 22;24(3):206-10. Epub 2015 Sep 22.

Kirov Medical Academy, St. Petersburg 194 044, Russia.

A possibility to use the Membrane-Introduction Mass Spectrometry (MIMS) with membrane separator interface has evolved into a powerful method for measurement of anaesthetic agents absolute concentration in blood plasma and cerebrospinal fluid for the study of blood-brain barrier (BBB) properties. Recent advanced a new membrane material was used for drug concentration measurement in biologic fluids. A hydrophobic membrane was used in the interface to separate anaesthetic agents from biological fluids: inhalational anaesthetic desflurane,hypnotic propofol, analgesic fentanyl. The selective detection of volatile anesthetic agents in blood does not require long-term sample processing before injecting the sample into mass-spectrometer interface, in contrast to chromatographic methods. Mass-spectrometric interface for the measurement of anaesthetic agent concentration in biological fluids (blood plasma and cerebrospinal fluid) is described. Sampling of biological fluids was performed during balanced inhalational (desflurane, fentanyl) anaesthesia and total intravenous (propofol, fentanyl) anaesthesia.
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http://dx.doi.org/10.5607/en.2015.24.3.206DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4580747PMC
September 2015

[Mass-spectrometric control of compound A during minimal flow anesthesia and its influence on liver and kidneys functions].

Anesteziol Reanimatol 2013 Jul-Aug(4):14-8

The article contains results of mass-spectrometric control of sevoflurane and compound A concentrations during inhalation anesthesia with minimal flow (< or = 0.5 l/min) and its influence on liver and kidney function. 40 patients (ASA I-II) were included in the study. Transsphenoidal pituitary adenomectomy was performed in all cases. Patients didn't have any signs of liver or kidneys disfunctions preoperatively. We used quadrupole mass spectrometer "Prisma Plus" (Pfeiffer vacuum, Germany) to determine the real time concentration of sevoflurane and compound A. Intensity of m/z = 131 peak sevoflurane and m/z = 128 peak compound A were registered. Laboratory blood tests to assess liver and kidney function were carried out before anesthesia, after anesthesia, and on the 1st day after anesthesia. They included: AST, ALT, total bilirubin, total protein, urea, creatinine. Quantitative analysis of the compound A and blood test before and after anesthesia showed only a tendency to increase biochemical markers levels within normal range, except small, but significant, AST elevation and total protein reduction in postoperative period. We concluded that maximal registered level of compound A (275 ppm/h) during minimal flow anesthesia didn't associate with significant liver and kidneys injury in healthy patients.
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February 2014

Mass-spectrometric monitoring of anesthesia adequacy.

Bull Exp Biol Med 2013 Oct;155(6):814-6

A.F. Ioffe Physics and Technology Institute, Russian Academy of Sciences, Saint Petersburg, Russia.

Anesthesia adequacy was assessed with mass-spectrometric method by monitoring the ratio of mass concentrations of end-tidal CO2 and inhaled O2 in every respiratory cycle during surgery. For real-time monitoring, we used a mass spectrometer with electron ionization connected to the respiratory contour of inhalation anesthesia machine. The study has demonstrated advantages of the novel method in real-time assessment of adequacy of the total intravenous anesthesia.
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http://dx.doi.org/10.1007/s10517-013-2259-1DOI Listing
October 2013

Early clinical PET imaging results with the novel PHF-tau radioligand [F18]-T808.

J Alzheimers Dis 2014 ;38(1):171-84

Siemens Molecular Imaging, Inc., Culver City, CA, USA.

Aggregates of hyperphosphorylated tau (PHF-tau), such as neurofibrillary tangles, are linked to the degree of cognitive impairment in Alzheimer's disease. We have recently reported early clinical results of a novel PHF-tau targeting PET imaging agent, [F18]-T807. Since then, we have investigated a second novel PHF-tau targeting PET imaging agent, [F18]-T808, with different pharmacokinetic characteristics, which may be favorable for imaging Alzheimer's disease and other tauopathies. Here, we describe the first human brain images with [F18]-T808.
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http://dx.doi.org/10.3233/JAD-130098DOI Listing
June 2014