The review provides information on the possibilities and significance of computed tomography (CT) angiography as a method of postoperative control of cerebral aneurysms after treatment (surgical clipping or endovascular embolization). The comparison of the diagnostic value of CT and cerebral angiography as a routine method of postoperative control is shown. The possibilities of improving the methods of scanning and post-processing in the framework of CT angiography are described for better visualization of the completeness of aneurysm shutdown, as well as minimizing artifacts from surgical clips and coils.

Introduction. Cancer metastases from an unknown primary origin (CUP) in the head and neck area include a large heterogeneous group of tumor formations, the primary localization of which could not be established even after a thorough diagnostic search. Combined positron emission computed tomography (PET-CT) with ¹⁸F-FDG has a high level of detection of primary neoplasms as a result of simultaneous acquisition of precisely combined anatomical and functional images of the entire body.
Objectives. 1. To evaluate the possibility of using PET-CT (positron emission tomography in combination with computed tomography) with ¹⁸F-FDG (18-fluorodeoxyglucose) in patients with metastases from the CUP (carcinoma unknown primary) in the head and neck.
2. To determine the effectiveness of PET-CT for the detection of primary tumor focus in patients with histologically verified diagnosis of CUP in the head and neck.
3. To evaluate the contribution of the PET-CT technique in assessing the prevalence of the disease in patients diagnosed with head and neck cancer.
Materials and methods. 134 patients diagnosed with CUP in the head and neck from September 2018 to March 2019 were included to this retrospective study: 35(26.1%) women and 99(73.9%) men, with the mean age of 61.9 ± 7.5 years. All patients underwent a biopsy from at least one metastatic lesion, and the malignant nature of the neoplasm was histologically verified. Before PET-CT with ¹⁸F-FDG, standard oncological evaluation was carried out to detect primary tumor.
Results. Among 134 patients comprised the study, initial histological diagnoses were: squamous cell cancer (n = 82, 61.2%), melanoma (n = 5, 3.7%), undifferentiated carcinoma (n = 20, 15%), adenocarcinoma (n = 21, 15.6%) and undifferentiated malignant neoplasm (n = 6, 4.5%).
With PET-CT with ¹⁸F-FDG, primary tumor location was revealed in 72 (54%) of the patients. New metastatic lesions were found in 60 (44.7%) of the patients.
Change in the TNM stage was observed in 95(71%) of all cases after PET-CT with ¹⁸F-FDG. It was associated both with the detection of the primary tumor and the identification of new metastatic foci.
Conclusions. Use of PET-CT with ¹⁸F-FDG allows to carry out oncological evaluation more precisely than the standard procedures in the majority of patients with CUP in the head and neck region. In a significant quota of cases, this method is in a position also to help to identify the primary tumor lesion, which, in turn, influences on strategy of treatment and also on the prognosis of disease. PET-CT with ¹⁸F-FDG should be included to the protocol of radiological examination in patients with CUP in the head and neck anatomic area.

The concept of “contrast-induced acute renal injury” (CI-AKI) is an increase in the level of plasma creatinine, recorded within 48 hours after contrast drug administration. This condition is the third most common cause of chronic renal failure occurring in a hospital. Despite the rather frequent occurrence of this phenomenon, it is not completely clear whether all such cases can really be explained by the exceptionally wide spread of procedures with contrast agent administration, because a decrease in kidney function is often found in inpatient patients. Since there is no treatment for CI-AKI, many groups of scientists have attempted to develop a prevention regimen. However, such measures are fraught with a number of difficulties: possible consequences for patients, logistical difficulties in a medical institution, costs of funds. The effectiveness of these measures has also not been unequivocally proven. In particular, in the course of a large AMACING study, it was shown that hydration does not reduce the likelihood of developing CI-AKI, but significantly increases the patient's treatment costs and can cause specific complications. In addition, there is a lot of literature evidence in favor of the fact that the hydration technique is effective for preventing a decrease in kidney function only in patients who have undergone intra-arterial administration of a contrast agent. Thus, the need for drug prevention of CI-AKI is currently being questioned, research in this area is actively continuing.

The article discusses the latest achievements of radiation diagnostics in the examination of patients with suspected breast cancer at various stages. The possibilities of dual-energy contrast spectral mammography, magnetic resonance imaging in the primary diagnosis of the disease and in assessing the prevalence of the process, the involvement of the contralateral breast, the optimal methodology of the study and the principles of interpretation of the data obtained in daily practice are discussed.

Presurgical brain mapping of language-eloquent cortex aims to minimize its injury during neurosurgery in patients with brain tumors and drug-resistant epilepsy, and thereby, to preserve their quality of life. Two main goals of language mapping are to identify the localization and lateralization of brain regions involved in language. Gold standards for them are the intraoperative mapping and Wada test, respectively; however, due to some limitations of these techniques, non-invasive preliminary language mapping becomes reasonable. During the last years, fMRI has been widely applied for such purposes. Our literature review focuses on innovations and actual tendencies which spread in the field of language mapping via fMRI in the last decade. State-of-the-art knowledge on brain organization of language, which underpins brain mapping of language processing via fMRI, is briefly described in the article. Contemporary studies of fMRI validity in localization and lateralization of language brain regions are considered. Strategies of presurgical language mapping, such as application of tractography in addition to fMRI, combined analysis of fMRI tasks as well as resting-state fMRI are also discussed. Well-established fMRI tasks for brain mapping of language production and comprehension, as well as new experimental developments in this field, are listed and described.

MSCT is known for its extremely high diagnostic accuracy in coronary artery stenosis detection and quantification. However, there are still questions about physiological assessment of myocardial ischemia, since the degree of arterial stenosis and clinical outcomes do not always correlate. It is also noted that the exclusive use of functional non-invasive tests to assess the grade of stenosis can lead to false-negative results and worsen the long-term prognosis of cardiovascular events. Thus, the combined use of anatomical and functional tests can improve the prognosis in coronary heart disease patient. MSCT coronary angiography, combined with stress perfusion and/or CT derived fractional flow reserve, could be used as an all-in-one approach. This review describes new applications of cardiac MSCT.

Spontaneous pneumomediastinum, pneumothorax, pneumoperitoneum, and soft tissue emphysema have been recently described in several sources as possible complications in patients with severe COVID-19 and lung damage. This clinical case is dedicated to demonstrarte the development of these lesions in 3 male patients with comorbid conditions. The putative pathophysiological mechanism of these complications is air leakage due to extensive diffuse alveolar damage followed by rupture of the alveoli. All presented patients had a favorable outcome of the disease without lethal cases, their laboratory data and clinical dynamics were described.
It should be noted that such conditions are not rare complications of COVID-19, and are observed mainly in male patients with severe form of the disease and the presence of comorbid conditions. Such complications are associated with long hospitalization and a severe prognosis. In some cases, with a mild course of the disease and positive dynamics in a decrease of the percentage of pulmonary lesions, the outcome is favorable, not requiring additional invasive interventions.

Introduction. The development and improvement of new tomographic technologies for highly sensitive imaging of lung cancer (LC) is crucial for the early detection of this disease, accurate staging and control of complex therapy
The purpose of the study. To study the possibility of using the radiopharmaceutical (rp) ¹⁹⁹TlCl for SPECT-CT imaging of LC.
Material and methods. ¹⁹⁹TlCl in solution was obtained at the U-120 cyclotron (Efremov Institute of Physics and Technology, Rosatom, St. Petersburg) of the TPU Institute of Physics and Technology by the reaction of irradiation of a metal gold target with alpha particles ¹⁹⁷Au(α,2n)¹⁹⁹Tl, at an alpha particle energy of 28 MeV, with a ¹⁹⁹Tl yield of over 95%, in saline solution. The injected dose of rp was 180–185 MBq in all cases, and the scan was performed in 12–20 minutes after the injection of ¹⁹⁹TlCl. The chest SPECT was acquired as 64 planar scans per 360° rotation of the two-detector system, in a 64 × 64 matrix, with a field of view size of 40 × 40 cm, with acquisition of more than 50,000 pulses per frame, with a high-energy high-resolution collimator installed, with an energy peak of 70 keV set at a window width of 20% of the differential discriminator. The axial sections were reconstructed using the back-projection method, taking into account the depth absorption with an absorption constant of 0.12 1 / cm. The contour of the patient's body for this purpose was imported from the CT. CT of chest was carried out immediately after the SPECT, ro the 512 × 512 matrix, with a spatial resolution of 1 mm. No X-ray contrast enhancement was carried-out. All studies were performed using a combined SPECT-CT scanner Simbia T16 (Siemens Medical).
We recruited 12 patients with an established diagnosis of non-small cell LC, in everybody the SPECT-CT with ¹⁹⁹Tl-chloride was employed to stage the disease. The control group comprised 7 patients who underwent a study with ¹⁹⁹Tl-chloride for non-oncological pathology, but the diagnosis was finally rejected.
Results. Visually, in SPECT-CT with ¹⁹⁹TlCl in patients without tumor pathology, the accumulation in the lungs was close to background, and the image of the mediastinum was due to the normal accumulation of rp to the heart muscle. Ratio “healthy lung/myocardium” was 0.23 ± 0.05 in the control group. For the primary node of LC, this index was 0.62 ± 0.14 (p < 0.02), and for metastatically involved lymph nodes, 0.59 ± 0.16 (p < 0.05). According to the results of the individual picture of SPECT-CT with ¹⁹⁹TlCl in LC, 6 patients out of 12 had expanded radiation areas during external gamma therapy.
Conclusion. ¹⁹⁹TlCl has a high affinity to the LC tumor tissue and shows high accumulation both to the primary and to metastatic LC foci. Routine use of SPECT-CT with ¹⁹⁹TlCl in LC makes sence, both in the primary diagnosis and for the staging of the disease. It is necessary to continue the study of ¹⁹⁹TlCl as rp for both ptimary diafnostic imagung of LC and also for the follow-up control of therapy.

Material and methods. A prospective, randomized, single-center study was conducted. It included 166 patients with mitral valve disease divided into three groups depending on types of AF: with paroxysmal AF at 14 (8.4%) patients, with persistent AF at 63 (37, 9%) patients and with long-term persistent AF at 89 (53.6%) patients hospitalized at the Interregional Clinic and Diagnostic Center Kazan from 2011 to 2018. An average age of patients was 57 ± 5 years old, mainly females amounted to 97 (58.4%).
Results. Surgical isolation of the pulmonary vein ostia and the left atrium by RFA at mitral valve replacement significantly improves the contractile function of the left atrium, which allows us to judge about the improvement of the transport function of the left heart chambers as a whole.

Aim. To study the features of contrast enhancement of malignant neoplasms of the liver in patients with and without cirrhosis (LC), to study the differences in the dynamics of contrast enhancement of liver are metastatic lesions (MTS) and hepatocellular carcinoma (HCC).
Material and methods. A retrospective analysis results 58 patients with HCC (group 1) and 51 patients with liver metastases (group 2) was carried out based on morphological data. According to the criterion for the presence of LC, group 1 was divided into two subgroups. The main method of radiological diagnostics was contrast enhancement ultrasound (CEUS).
Results. The indicators of the dynamics of the Wash-in of an ultrasound contrast agent into the HCC node and the dynamics of the drug WASH-OUT from the focus in patients with LC did not significantly differ from those in patients without cirrhosis. HCC is characterized by the onset of leaching of the ultrasound contrast agent after 62 seconds from the beginning of the study, which significantly differs from MTS (p <0.05). The parameters in predicting the G3 stage of the tumor were as follows: the parameter “onset of WASH-OUT” of the from the focus <79 sec, the parameter “time of maximum WASH-OUT” of the ultrasound contrast agent <270 seconds. In our opinion, certain difficulties are presented by the diagnosis of highly differentiated carcinomas due to the absence of the WASH-OUT phenomenon in 50% of patients. Differential diagnosis of metastases should be based on a combination of a number of signs, the most important of which, in our opinion, are: early onset of elution of ultrasound contrast agent, “black hole” symptom, peripheral ring-shaped enhancement in arterial phase.
Conclusion. The data obtained with the help of CEUS confirm the effect of “arterialization of hepatic blood flow” in patients with LC. Differences in the parameters of contrasting HCC nodes in subgroups of patients with and without LC are not statistically significant. The polymorphism of the signs detected in MTS in the liver is due to the morphology of the primary tumor and the size of the neoplasms. Differential diagnosis should be based on a combination of signs of the dynamics of ultrasound contrast agents.

Portal vein thrombosis is one of the most common complications of liver cirrhosis, the risk factors for which are still not fully understood.
Purpose: to develop a prognostic model to determine the likelihood of portal vein thrombosis based on anamnestic, etiological factors, the presence of hepatocellular carcinoma, as well as parameters of CT perfusion of liver tissue.
Material and methods. 43 patients with compensated liver cirrhosis (58.1% of men) and 38 patients with subcompensated liver cirrhosis (50% of men) were included in the prospective study. The age of patients in the first group was 52.56 ± 9.62 years, in the second group - 50.95 ± 9.94 years. The number of patients with 1 etiological factor of liver cirrhosis in the study groups was 62.8% and 81.5%, respectively. Type 2 diabetes mellitus was exhibited in 23.3% of patients with compensated liver cirrhosis and in 15.8% of patients with subcompensated liver cirrhosis. The diagnosis of hepatocellular carcinoma was established in 27.9% of patients with compensated liver cirrhosis and in 18.4% of patients with subcompensated liver cirrhosis. All patients, after the native study, underwent CT perfusion of the liver using a 256-slice Philips ICT apparatus. As a result of postprocessing, the values of arterial, portal, total perfusion and perfusion index of liver tissue were determined. Statistical analysis of the data was carried out using the binary logistic regression method and the construction of ROC curves.
Results. A logistic stepwise multivariate analysis showed that an increase in arterial perfusion (p = 0.002) and a decrease in portal perfusion (p = 0.004) were independently associated with portal vein thrombosis in patients with compensated liver cirrhosis, and a history of primary liver cancer (p < 0.001) was a dependent factor in this model. In patients with subcompensated liver cirrhosis, a history of hepatocellular carcinoma (p < 0.001) and a decrease in portal perfusion (p = 0.001) became independent predictors of portal vein thrombosis, male gender (p = 0.029) was a dependent factor in the developed model.
Conclusion. CT-perfusion of the liver makes it possible to determine predictors that can be used together with such factors as the presence of hepatocellular carcinoma and gender in the construction of prognostic models to determine the likelihood of portal vein thrombosis in patients with compensated and subcompensated liver cirrhosis. Age, etiological factor and the presence of type 2 diabetes mellitus in the developed models were not statistically significant.

The aim of the study is to determine the influence of liver shapes on the accuracy of estimating the organ volume and assessment of hepatomegaly on CT. To develop approaches to improve the accuracy of calculations for various forms of liver.
Material and methods. The work is based on the analysis of the results of 603 abdominal CT examinations available in the radiological information systems of the city of Moscow. Six dimensions of the liver were measured: transverse, vertical and anteroposterior dimensions of the right and left lobes. Using automatic segmentation, performed in special software systems IntelliSpase Portal (Philips) and Synapse 3D (Fuji), the maximum close to the true liver volume was calculated. This made it possible to carry out a mathematical analysis to obtain various formulas for calculating the liver volume, depending on its shape. A comparative assessment of the sensitivity and specificity of the developed formulas and the standard one, which does not take into account the shape of the liver, was carried out in relation to the diagnosis of hepatomegaly.
Results. During the study, the four most common types of liver forms were identified, for each of which, based on mathematical approaches, formulas for calculating the organ volume were developed. Comparative analysis of these formulas and the previously developed by us standard one showed that the root-mean-square error decreases using the formula for a certain type of liver shape. However, the sensitivity and specificity of the diagnosis of hepatomegaly in the differential approach do not change compared with the standard formula.
Conclusion. The existing difference in the forms of the patients’ liver does not significantly affect the approaches to determine the organ volume and establishing the fact of hepatomegaly during CT. Therefore, the standard formula for determining liver can be used in clinical practice: V = (HRL+TRL)³/21, (V – volume, HRL – high of right lobe, TRL – thickness of right lobe).

Purpose. Improving the efficiency of CT in the differential diagnosis of mass-forming pancreatitis (MFP) and pancreatic ductal adenocarcinoma (PDAC) making a diagnostic model based using a combination of texture features and contrast enhancement features.
Methods and materials. 45 patients with histologically confirmed non-metastatic locally advanced PDAC and 13 patients with MFP where underwent CT examination with contrast enhancement. For each group, the ratio of the densities of intact pancreatic tissue and tumors, the relative tumor enhancement ratio (RTE) in all enhanced phases of CT, 94 texture features for each phase of the study were calculated and compared. The selection of predictors in the logistic model was carried out in 2 stages: 1) selection of predictors based on one-factor logistic models, the selection criterion was p_adj <0.2; 2) selection of predictors using LASSO-regression after standardization of variables. The selected predictors were included in a logistic regression model without interactions.
Results. There were statistically significant differences in 14, 17, 4 out of 94 for the unenhanced, arterial, and venous phases of the study, respectively (p < 0.05). After selection, the final diagnostic model included the texture features CONVENTIONAL HUQ2 and DISCRETIZED HUQ1 for the unenhanced phase, DISCRETIZED HUQ1 and GLRLM RLNU for the arterial phase, DISCRETIZED Skewness for the venous phase, RTE for the delayed CT phase. The diagnostic model was built showed an accuracy of 81% in the diagnosis of MFP.
Conclusion. We have developed a diagnostic model, including textural parameters and contrast enhancement features, which allows preoperatively distinguish MFP and PDAC, the developed model will increase the accuracy of preoperative diagnosis.