During the pandemic of novel coronavirus infection (COVID-19), computed tomography (CT) showed its effectiveness in diagnosis of coronavirus infection. However, ionizing radiation during CT studies causes concern for patients who require dynamic observation, as well as for examination of children and young people. For this retrospective study, we included 15 suspected for COVID-19 patients who were hospitalized in April 2020, Russia. There were 4 adults with positive polymerase chain reaction (PCR) test for COVID-19. All patients underwent magnetic resonance imaging (MRI) examinations using MR-LUND PROTOCOL: Single-shot Fast Spin Echo (SSFSE), LAVA 3D and IDEAL 3D, Echo-planar imaging (EPI) diffusion-weighted imaging (DWI) and Fast Spin Echo (FSE) T2 weighted imaging (T2WI). On T2WI changes were identified in 9 (60,0%) patients, on DWI – in 5 (33,3%) patients. In 5 (33,3%) patients lesions of the parenchyma were visualized on T2WI and DWI simultaneously. At the same time, 4 (26.7%) patients had changes in lung tissue only on T2WI. (P(McNemar) = 0,125; OR = 0,00 (95%); kappa = 0,500). In those patients who had CT scan, the changes were comparable to MRI. The results showed that in case of CT is not available, it is advisable to conduct a chest MRI for patients with suspected or confirmed COVID-19. Considering that T2WI is a fluid-sensitive sequence, if imaging for the lung infiltration is required, we can recommend the abbreviated MRI protocol consisting of T2 and T1 WI. These data may be applicable for interpreting other studies, such as thoracic spine MRI, detecting signs of viral pneumonia of asymptomatic patients. MRI can detect features of viral pneumonia.

Planning and predicting the processes of biological tissues heating associated with therapeutic effects involves high-precision mathematical modelling. However, the thermophysical properties of tissues can vary greatly from patient to patient. The paper presents a computational and experimental method for identifying mathematical models of heat transfer, not involving the placement of temperature sensors inside of the studied object. The experimental setup consists of a flat sample of the material, a laser setup, and a thermal imaging camera. The surface thermal response to the pulsed heat flux of the laser is an array of input data for the developed software package. The heat transfer coefficient and heat flux density are determined iteratively by minimizing the residual functional between the calculated and experimental values. The method was tested when determining the characteristics of a specimen of low-pressure polyethylene. The result was obtained in 5 iterations and under the influence of external natural convection, and without taking into account the translucency of the material, a discrepancy of calculated and experimental values of 3.5% was shown. The method can be used to plan the therapeutic process in order to ensure its maximum effectiveness.

The nuclear medicine phantom development is based on the step by step description of the computational and experimental biological object model. Computational phantoms are used for geometry of the object description and simulate physics of particle interactions with matter, while experimental phantoms are used for quality control tests and standardization of functional research protocols. Common examples are the dosimetry planning of radionuclide therapy and post-therapeutic scintigraphy with 131I. This review provides a list of methods for computational and experimental phantoms. Examples of existing phantoms created for the nuclear medicine tasks are also given.

During the pandemic of COVID-19, computed tomography showed its effectiveness in diagnosis of coronavirus infection. However, ionizing radiation during CT studies causes concern for patients who require dynamic observation, as well as for examination of children and young people. For this retrospective study, we included 15 suspected for COVID-19 patients who were hospitalized in April 2020, Russia. There were 4 adults with positive polymerase chain reaction (PCR) test for COVID-19. All patients underwent MRI examinations using MR-LUND PROTOCOL: Single-shot Fast Spin Echo (SSFSE), LAVA 3D and IDEAL 3D, EPI diffusion-weighted imaging (DWI) and Fast Spin Echo (FSE) T2WI without using respiratory or any other trigger. 3 patients also had CT scan performed. In 5 (33,3%) patients, detected lesioins were visualized on T2WI and DWI simultaneously. At the same time, 4 (26.7%) patients revealed lung tissue changes only on T2WI (P(McNemar)= 0,125, OR= 0,00 (95%), kappa=0,500). Pulmonary changes on MRI were also analyzed depending on their localization. In those patients who had CT scan, the changes were comparable to MRI. MRI of the lungs can detect features of viral pneumonia and assess severity of lung damage. The method can be used to diagnose COVID-19. These data may be applicable for interpreting other studies, such as thoracic spine MRI, detecting signs of viral pneumonia of asymptomatic patients. The current study was limited by a small sample size and absence of chest CT scans of all patients.

Background The paper covers modern approaches to the evaluation of neoplastic processes with diffusion-weighted imaging (DWI) and proposes a physical model for monitoring the primary quantitative parameters of DWI and quality assurance. Models of hindered and restricted diffusion are studied. Material and method To simulate hindered diffusion, we used aqueous solutions of polyvinylpyrrolidone with concentrations of 0 to 70%. We created siloxane-based water-in-oil emulsions that simulate restricted diffusion in the intracellular space. To obtain a high signal on DWI in the broadest range of b values, we used silicon oil with high T2: cyclomethicone and caprylyl methicone. For quantitative assessment of our phantom, we performed DWI on 1.5T magnetic resonance scanner with various fat suppression techniques. We assessed water-in-oil emulsion as an extracorporeal source signal by simultaneously scanning a patient in whole-body DWI sequence. Results We developed phantom with control substances for apparent diffusion coefficient (ADC) measurements ranging from normal tissue to benign and malignant lesions: from 2.29 to 0.28 mm2/s. The ADC values of polymer solutions are well relevant to the mono-exponential equation with the mean relative difference of 0.91%. Conclusion The phantom can be used to assess the accuracy of the ADC measurements, as well as the effectiveness of fat suppression. The control substances (emulsions) can be used as a body marker for quality assurance in whole-body DWI with a wide range of b values.