INTRODUCTION: The term vestibulopathy describes a dysfunction of the vestibular portion of the inner ear that manifests as a sporadic or constant dizziness and unsteadiness when walking. The symptoms of vestibulopathy may be caused be a large number of reasons and can accompany a variety of pathological conditions or be an innate trait.
OBJECTIVE: To demonstrate the importance of a multimodal approach in radiology of vestibular disorders and to highlight the typical semiotics of the causes of dizziness that can be assessed by imaging methods.
MATERIALS AND METHODS: The description of findings in this work is based on a routine examination of patients referred for CT and MRI with complaints of dizziness, often in combination with hearing loss.
RESULTS: This paper describes the role of CT and MRI in diagnosing various causes of vestibulopathy.
DISCUSSION: Vertigo is a multifactorial condition often with fluctuating symptoms, the ambiguous clinical presentation makes it difficult to make a diagnosis solely on the basis of clinical data, which necessitates the need for an integrated approach to the examination of patients with balance issues. This article outlines key anatomical features, pathological conditions and the corresponding diagnostic findings.
CONCLUSION: CT and MRI are an integral part of a comprehensive examination of patients with vestibular disorders and impact further patient management tactics.

INTRODUCTION: In many cases physicians make a diagnosis using the results of radiology. At the same time, the interpretation of medical images can be very variable in some cases, contain inaccuracies, which can lead to incorrect patient treatment tactics. OBJECTIVE: The aim of this article is to show different classification of diagnostic errors in radiology.
MATERIAL AND METHODS: A search for scientific publications was carried out in the information and analytical systems PubMed, elibrary, Google Scholar using the keywords: radiology errors, x-ray errors, diagnostic errors in radiology, errors in radiation diagnostics, errors in radiology.
RESULTS: An analysis of scientific publications showed different approaches to the classification of errors in radiology. The main historical aspects of the formation of the first such classifications, their improvement over time, the lack of a single agreed upon classification and the critical difficulties of their use are presented.
CONCLUTIONS: This literature review presents various approaches to the classification of errors in radiation diagnostics, which can be useful for understanding the causes of their occurrence, as well as for the development of systems for their identification, analysis and prevention, which will subsequently lead to minimizing the frequency of their development and reducing the degree of damage caused.

INTRODUCTION: Extracranial neurogenic tumors in children are represented by neoplasms of the sympathetic nervous system and adrenal medulla: ganglioneuromas, ganglioneuroblastomas and neuroblastomas. The main prognostic factors used to stratify patients into risk groups and, in many ways, determine the effectiveness of treatment are the histological type of the tumor and the presence of MYCN gene amplification.

OBJECTIVE: To evaluate the capabilities of quantitative MRI to determine the histological variant of neurogenic tumors and predict the presence of MYCN gene amplification in children.

MATERIALS AND METHODS: We retrospectively analyzed the data of 110 patients with primary peripheral neurogenic tumors who underwent therapy or received an advisory opinion at the D.Rogachev National Medical Research Center for Pediatric Orthopedics and Pediatric Orthopedics in the period from 2012 to 2022. with diagnoses of ganglioneuroma — 12, mixed ganglioneuroblastoma — 10, neuroblastoma — 88. The age of patients at the time of diagnosis ranged from 15 days to 16 years, median age — 17 months. Before surgery and therapeutic interventions, all patients underwent diffusion-weighted MRI and a tumor biopsy to determine MYCN gene amplification using FISH.

Statistics: To determine the threshold values of the apparent diffusion coefficient (ADC) of neurogenic tumors of various histological structures, as well as with the presence and absence of MYCN gene amplification, ROC analysis (receiver operating characteristic) was used. Differences in qualitative parameters in the studied groups of patients were analyzed using the χ2 test, and quantitative ones — using the Mann-Whitney and Kruskal-Wallis tests.

RESULTS: Threshold values of the ADC index were determined to reliably differentiate neurogenic tumors rich in Schwann stroma (ganglioneuromas and ganglioneuroblastomas, ADC≥1.25 mm²/s) and neuroblastomas, as well as neuroblastomas without MYCN gene amplification (0.78<ADC <1.25 mm²/s) and with the presence of amplification (ADC≤0.78 mm²/s). In the first case, sensitivity was 0.95, specificity — 0.94; in the second — 0.94 and 0.75, respectively.

DISCUSSION: Our data indicate the possibility of separating histological types of neurogenic tumors on the basis of quantitative MRI; the ADC value makes it possible to differentiate ganglioneuromas and ganglioneuroblastomas from neuroblastoma, as well as to distinguish neuroblastoma with the presence of MYCN gene amplification and without this genetic event. Non-invasive quantitative MRI makes it possible to assess the entire tumor volume at the diagnostic stage, and an extremely low ADC value radiogenomic sing for the presence of MYCN gene amplification in neuroblastoma.

CONCLUSION: Quantitative MRI with determination of ADC of neurogenic tumors allows not only to separate the histological variants of neurogenic tumors, but also to predict the presence of MYCN gene amplification as the most unfavorable genetic marker of neuroblastomas.

INTRODUCTION: Identification of brain glioma recurrence and necrosis — is actual neurosurgical problem, due to an absence of particular radiological signs on MRI image. Especially in the early stages. Identification of brain glioma recurrence and necrosis on MRI images — is a problem of object`s classification on medical images. Depending on this, an issue of chemotherapy is decided. OBJECTIVE: Development and practical approbation of a method for differential diagnostic of a recurrent glial tumor from radiation necrosis on MRI images by using mathematical model of medical image`s processing.
MATERIALS AND METHODS: Analysis of existing methods for differential diagnostic of a recurrent glial tumor from radiation necrosis and description of principal deficiencies’ description. Authors proposed an algorithm for differential diagnostic of a recurrent glial tumor from radiation necrosis. Development of algorithmic, structural and mathematical models for proposed solution: prototype of an app and an interface. Testing of proposed method on the practice: dynamic examination for 98 patients with brain glioma Grade III–IV — brain MRI with contrast enhancement 1, 3, 6, 9, 12 months after surgical intervention and a chemotherapy.
RESULTS: As a result of practical approbation, authors’ noticed that this method has a high level of brain glioma recurrence and radial necrosis detection (97,4%).
DISCUSSION: The variety of scientific papers describing ways to differentiate recurrence of glial brain tumors and radiation necrosis based on MRI diagnostics confirms the relevance of the topic of the article in the medical scientific community. We have developed a method of differential diagnosis using MRI of the brain with contrast enhancement, due to the fact that this is the most accessible method of diagnosis in the postoperative period and a course of chemoradiotherapy.
CONCLUSION: A high-precision method for differential diagnosis of radial necrosis and brain glioma recurrence using a clinical decision support system allows the neurosurgeon to timely adjust treatment tactics, thereby improving the survival rates of patients with Grade III–IV glial tumors.

INTRODUCTION: Primary hyperparathyroidism (PHPT) is a common endocrine disorder. Minimal invasive parathyroidectomy (PTX) is favorable surgical approach in PHPT treatment. Its success is highly dependent on accurate preoperative localization of all causative parathyroid adenomas. Despite the fact that wide range of visualization methods are applied in PHPT diagnostics, PHPT persistence occurs. Therefore, the search for additional visualizing tools of parathyroid adenomas remains relevant. Recently, positron emission tomography/computed tomography (PET/CT) has been used in order to improve PHPT diagnostics. OBJECTIVE: To evaluate the diagnostic effectiveness of PET/CT with ¹¹C-methionine and ¹¹C-choline in patients with PHPT based on the intensity of both tracers uptake in parathyroid adenomas. 
MATERIALS AND METHODS: The data of 26 patients diagnosed with PHPT was analyzed. PET/CT with ¹¹C-choline was performed in 14 patients, with ¹¹C-methionine — in 10 patients, with two radiopharmaceuticals — in two patients. All patients underwent PTX. Histological examination’s results were compared with the results of PET/CT. Using the software, the standardized uptake value of radiopharmaceuticals in histologically verified parathyroid adenomas/hyperplasias and in the trapezius muscle was obtained, then tumor-to-background ratios (TBR) of ¹¹C-methionine and ¹¹C-choline were calculated.
Statistics: Software STATISTICA 10 was used in statistical analysis.
RESULTS: ¹¹C-choline TBR median was of 2.3 (1.6; 3.2), median of ¹¹C-methionine TBR showed slightly higher values — 2.5 (1.9; 3,6). However, no significant difference was found between the two radiopharmaceuticals’ uptake in parathyroid adenomas.
DISCUSSION: The scientific impact of current study is determined by the diagnostic effectiveness comparison between PET/CT with ¹¹C-methionine and ¹¹C-choline, which is based on the accumulation intensity of both radiopharmaceuticals in parathyroid adenomas.
CONCLUSION: The intensity of accumulation of ¹¹C-methionine and ¹¹C-choline by hyperfunctioning parathyroid tissue does not differ significantly. Thus both tracers might be successfully applied for topic diagnosis of parathyroid adenomas in patients with PHPT.

INTRODUCTION: Until now, diagnosis the subtype of pancreas cystic lesion remains a major challenge. The accuracy of preoperative invasive diagnosis procedures is still very difficult due to the low cellularity of the aspirate. Accuracy verification of nature lesion’s is essential for predicting tactical planning and planning interventions.

OBJECTIVE: To determine the diagnostic significance of texture analysis of contrast enhancement СT in differentiation of tumor and tumor-like pancreatic cystic lesions; to compare results of application of two models (2D and 3D) segmentation of CT images; to develop a diagnostic model including texture features to differentiate tumor and tumor-like pancreatic cystic lesions.

MATERIALS AND METHODS: Clinical and CT data of 40 patients with pancreatic cystic lesions were collected for this study. Among these patients, 15 were pathologically diagnosed with serous cystadenoma, 15 were diagnosed with mucinous cystadenoma and 10 were diagnosed with pseudocyst. The radiomic features were extracted from four CT phases (native, arterial, venous and delayed). All images were normalized prior to the radiomics analysis, using spatial resampling with fixed voxel size of 1 mm³ (RES) and density threshold from 0 to 200 HU. For each phase, one radiologist (3 year`s experience in abdominal imaging) segmented the lesion contour on each slice (3D) and on the slice with maximum axial diameter (2D).

Statistics: The program R 4.3.2 (R Foundation for Statistical Computing, Vienna, Austria) was used. The Mann-Whitney test and AUC with 95% confidence interval were used to assess the discriminative texture predictors for tumour types. Texture features were included in the analysis after standardization, and L1 (LASSO) regularization was used to select predictors. Finally, discriminative models were evaluated by bootstrap estimation and Matthews correlation coefficient.

RESULTS: Using 3D segmentation is preferable for differentiation of tumor and tumor-like pancreatic cystic lesions. A 2-D radiomics diagnostic model was included features (INTENSITY-HISTOGRAM_IntensityHistogram75^th Percentile, MORPHOLOGICAL_Volume, INTENSITY-BASED_StandardDeviation) from native and arterial phases. It was resulted in an average AUC 0.89, with an sensitivity and specificity 70 and 93.3% according to pseudocysts, 73.3 and 92% according to mucinous cystadenomas, 86.7 and 80% according to serous cystadenomas. A 3-D radiomics diagnostic model was included features (MORPHOLOGICAL_SurfaceToVolumeRatio, INTENSITY-BASED_StandardDeviation, GLCM_Correlation, GLSZM_ZonePercentage) from native, arterial and delayed phases. It was resulted in an average AUC 0.96, with an sensitivity and specificity 80 and 96.7% according to pseudocysts, 86.7 and 88% according to mucinous cystadenomas, 80 and 88% according to serous cystadenomas. DISCUSSION: Currently, textural analysis is aimed at solve two main problems — differentiation of histological classes and grade of pancreatic cysts. The standardization of pre-processing and segmentation remains an unresolved issue. At the time of this study, we haven`t found any papers analyzing all the phases of CT imaging. A review of publications revealed that in the majority of cases researchers analyzed only one phase (arterial/venous) by 3D-segmentation. In our study, four phases of CT (native, arterial, venous and delayed) were analyzed by two types of segmentaion. In order to reduce texture ranges and offset the segmentation errors, we investigate preprocessing steps such as density distribitions (0–200 HU) and voxel resampling 1 mm<sup>3</sup> (RES). In contrast to other papers, in our study there are no statistically significant textural features for the venous phase. Also, we don`t identify higher-order textural features as a differentiation predictors.

CONCLUSION: Texture analysis of contrast enhancement СT have a favorable differential diagnostic performance for tumor and tumor-like cystic lesions of the pancreas.

INTRODUCTION: Determining the nature of focal liver pathology is an important issue, especially in oncological practice. Imaging methods with contrast enhancement are the main methods for diagnosing pathology of the hepatobiliary tract, however, there are limitations in the use of computed tomography, magnetic resonance imaging, and contrast-enhanced ultrasound. In recent years, acoustic radiation force impulse elastography has become a widely used method in assessing changes in the liver. This technique has been successfully used to quantify diffuse disease in the liver, and scientific research is currently being actively conducted to determine the threshold values of the stiffness of various liver lesions.
OBJECTIVE: To determine the possibility of an alternative method for differential diagnosis of solid liver lesions from pseudofocal lesions using the acoustic radiation force impulse elastography technique in the context of multiparametric ultrasound examination. MATERIALS AND METHODS: The study included 64 patients with a history of cancer. In all cases, contrast-enhanced computed tomography and multiparametric ultrasound using acoustic radiation force impulse elastography technology were performed to assess quantitative indicators of lesion stiffness in the non-cirrhotic liver. The minimum, average and maximum stiffness of the lesion was assessed, expressed in m/s based on the results of 10 measurements. The results obtained were compared with accepted standards for the stiffness of the liver parenchyma for assessing diffuse changes, recommended by EFSUMB. RESULTS: In accordance with the final clinical diagnosis, the studies included focal liver lesions: hemangioma (n=16; 25.0%), focal steatosis (n=19; 29.7%), metastases (n=29; 45.3%). We assessed three subgroups of values: the minimum value, the maximum and the average. The most important parameter used for further interpretation of the data is the average stiffness value based on the results of all measurements. When assessing this indicator for hemangioma, the median was 1.63 m/s, the standard deviation was 0.36, and the range was 1.02 m/s. For these focal lesions the 25th percentile is 1.47 m/s, the 75th percentile is 2.01 m/s. For metastatic lesions, the median was 1.83 m/s. When determining the standard deviation, this indicator was 0.34 m/s, and the range was 1.58 m/s. Also, the values of the 25th percentile were 1.68 m/s, and the 75th were 2.08 m/s. When analyzing these indicators of stiffness in focal steatosis, the following values were obtained: median — 1.09 m/s; range — 0.21 m/s and standard deviation — 0.06 m/s. The 25th percentile values were 1.025 m/s, the 75th percentile — 1.105 m/s. DISCUSSION: Based on the presented data, solid lesions, such as hemangioma and metastasis, had significantly high stiffness values in comparison with unchanged liver parenchyma. Our results are close to the values described in a number of large studies, but at the moment there is no consensus regarding the threshold values, as well as the methodology for performing the study and determining the zone for assessing stiffness in the lesion, which makes this technique promising for further study. CONCLUSION: Performing a multiparametric ultrasound examination using the technique of acoustic radiation force impulse elastography to assess quantitative indicators of stiffness in the lesion makes it possible to identify changes in the liver at the screening stage, conduct constant non-invasive monitoring of cancer patients, and determine further tactics for patient management. This technique is a promising, easily accessible, economical and, most importantly, dose-free diagnostic tool for detecting and characterizing liver lesion, allowing to reduce the time of differential diagnosis at the initial stage and reduce the costs of further research.

INTRODUCTION: Frequent detection of liver metastases in colorectal cancer and a high risk of adverse outcomes determine the algorithm for managing such patients, involving maximum early diagnosis and selection of treatment methods.
OBJECTIVE: To demonstrate the possibilities of CT and MRI in determining treatment tactics for colorectal liver metastases. MATERIALS AND METHODS: 90 patients with metastatic colorectal cancer in the liver were examined. All patients underwent contrast-enhanced CT. Multiparametric magnetic resonance imaging was performed in 49 patients (54%). The diagnosis was confirmed morphologically and/or by at least one additional method of examination (ultrasound or PET/CT).
RESULTS: When a solitary metastatic lesion in the liver or a limited number of lesions within one segment or lobe was identified, the preferred method was typical or atypical liver resection together with drug therapy (38.9%). In the presence of several small metastatic lesions, each with a diameter not exceeding 3 cm, and located far apart from each other, radiofrequency ablation was an additional method to liver resection (4.4%). For unresectable patients and/or non-resectable solitary lesions smaller than 5 cm without evidence of vascular invasion, the preferred method was stereotactic body radiation therapy (SBRT) (13.3%). Marked reduction in liver functional reserve, small remaining liver volume, as well as bilobar involvement precluded the resection of all lesions. Therefore, in cases of bilobar liver involvement where organ-preserving surgery is not feasible, with the presence of extrahepatic metastases, and when the patient is functionally unresectable, the preferred method was drug therapy (33.4%), transarterial chemoembolization (TACE) as a palliative therapy (10%).
DISCUSSION: According to the literature, the most sensitive methods for detecting liver metastases are MRI with diffusionweighted imaging (DWI) and the use of hepatospecific contrast agents in the hepatobiliary phase. CT is a reliable method for preoperative staging, providing high-quality visualization of the liver and covering the entire abdominal and thoracic cavities, allowing for the detection of metastases in regional lymph nodes and distant metastases. The statistical regularity we identified confirms these findings. However, in several studies, it has been noted that the sensitivity of MRI with hepatospecific contrast agents in the hepatobiliary phase is higher than DWI when detecting small lesions (less than 10 mm). According to the results of our study, MRI with DWI was found to be more sensitive for detecting small metastatic lesions.
CONCLUSION: Contrast-enhanced CT and multiparametric MRI showed high diagnostic value in the assessment of metastatic colorectal cancer in the liver for planning radical surgical intervention and selecting alternative treatment methods.

INTRODUCTION: CT colonography (CTC) is a highly accurate, minimally invasive method of intraluminal imaging of the colon using computed tomography. One of the main advantages of CTC compared to endoscopic colonoscopy is easier colon preparation due to the reduced volume of laxatives. However, colon cleansing, which includes dieting, is the most burdensome aspect of the entire procedure. At present, there is no consensus on the benefits of any dietary option for preparing the colon for CTC, and this issue requires further study.

OBJECTIVE: Comparison of the efficacy and tolerability of a one-day and a three-day diet at CT colonography (CTC).

MATERIAL AND METHODS: 107 patients were enrolled in this study. 55 patients adhered to a three-day diet (3DD) and 52 to a one-day diet (1DD). Each of six colonic segments was scored for residual fluid and stool using a 4-point scale (4 — absence; 3–1 — increasing fluid or stool). The quality of fecal tagging was assessed with fluid attenuation (HU values) and homogeneity (SD values). In addition, subjective severity of dieting and readiness to repeat the procedure were assessed.

Statistics: Comparison of groups after testing for normality of distribution was carried out using the Mann-Whitney U test for quantitative variables and using the Pearson χ² test for categorical data. A p value <0.05 was considered statistically significant. Cohen’s kappa analysis was performed to assess interobserver agreement. All calculations were performed using statistical software Jamovi version 1.2.27.

RESULTS: The mean residual fluid score was 37 (Q1–Q3 35–39) for 3DD and 36 (Q1–Q3 34–38) for 1DD, residual stool — 48 (Q1–Q3 46–48) and 48 (Q1–Q3 47–48) respectively. The median residual fluid attenuation was 887 HU (Q1–Q3 725– 1238 HU) and 953 HU (Q1–Q3 668–1203 HU), the median of homogeneity — 77 HU (Q1–Q3 55–86 HU) and 59 HU (Q1– Q3 47–92 HU). There was no significant difference in these parameters between groups (p>0.05). Difficulty of dieting was statistically significantly higher in 3DD group compared to the 1DD group (p=0.012): 26 patients (47.3%) from the 3DD group and 13 patients (25%). Readiness to repeat the procedure was significantly higher in 1DD group 75,0% (39 patients) than in 3DD group 54,5% (30 patients) (p=0.027).

DISCUSSION: A one-day diet before CTC provides optimal quality of preparation, and changing the diet from a three-day to a one-day increases the tolerability of the preparation in general, and also increases the willingness of patients to repeat the procedure in the future. The study also showed that there was no benefit to a clear liquid diet in preparation for CTC. For both diet options (one-day and three-day), the quality of preparation was high, and there were no statistically significant differences in the quality of preparation between groups.

CONCLUSION: Changing the diet from three-day to one-day doesn’t affect the quality of preparation for CTC, but increases patient’s tolerability and readiness to repeat the procedure.

INTRODUCTION: The instrumental methods currently used are either ionizing or invasive, which prevents their potential application in dynamic monitoring. Contrast-enhanced ultrasound (CEUS) can provide better assessment of renal blood flow.
OBJECTIVE: Increasing the diagnostic and prognostic value of ultrasound using echo contrast in the early diagnosis of clinically significant angioedema in patients with type 2 diabetes mellitus.
MATERIALS AND METHODS: From 2019 to 2023 On the basis of the Clinical Hospital No. 1 of Smolensk and the problem research laboratory «Diagnostic studies and minimally invasive technologies» of the Federal State Budgetary Educational Institution of Higher Education SSMU of the Ministry of Health of Russia, 166 people were examined (118 people — the main group (Group 1 — patients with type 2 diabetes without diabetic angioedema; group 2 — patients with type 2 diabetes with diabetic angioedema in the subcompensation stage; Group 3 — patients with type 2 diabetes with severe diabetic angioedema in the decompensation stage) and 48 people — the control group). All patients were examined according to a single diagnostic algorithm, which included 8 stages. Abstract methods — contrast-enhanced CT, dynamic nephroscintigraphy.
DISCUSSION: Unlike CT and MRI, CEUS is not nephrotoxic, which allows it to be used in patients with reduced renal function, including for multiple dynamic monitoring. This is relevant for patients with type 2 diabetes, because as the disease progresses, it is important to assess preclinical signs of diabetic angioedema, namely, intrarenal blood flow. The use of CEUS in a comprehensive diagnostic algorithm for diabetic kidney disease makes it possible to identify preclinical changes in diabetic angioedema. CONCLUSION: Contrast-enhanced ultrasound is a reliable and safe method of diagnosing kidney pathology, which allows predicting the clinical course of the underlying disease.

INTRODUCTION: Pseudomyxoma peritonei (PMP) is a rare pathology without specific clinical symptoms, predominantly asymptomatic in the early stages and can be difficult to diagnose; leads to extensive surgical procedures and reduced quality of life of the patient. PMB in most cases occurs due to invasion or perforation of a mucinous tumor of the appendix.
OBJECTIVE: To perform a dynamic follow-up of a patient with pseudomyxoma peritoneum of appendicular origin with asymptomatic course.
MATERIALS AND METHODS: A dynamic follow-up (from 2018 to 2024) of a 64-year-old female patient was performed. At the annual routine ultrasonography (USG) a moderate accumulation of fluid in the pelvic cavity was detected, which increased in dynamics. Computed tomography (CT) of the abdominal cavity and retroperitoneum was performed, and the results showed extended infiltrates, enlargement of the appendix lumen, and ascitic fluid in the peritoneal cavity. According to the histological study, a lowgrade appendicular mucinous neoplasms (LAMN) and pseudomyxoma of the peritoneum (low-grade mucinous carcinoma peritonei (LGMCP)) were verified. The patient underwent incomplete cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC). MRI or CT studies of the abdominal cavity and retroperitoneum were performed during dynamic follow-up.
RESULTS: The presence of a large volume of tumor masses, including those localized in the area of the liver gate, mesentery of the small intestine, did not allow to perform complete cytoreductive surgery with HIPEC. During dynamic observation, an increase in the size of peritoneal pseudomyxoma was noted.
CONCLUSION: A comprehensive approach, up-to-date diagnosis and identification of affected area help to determine the tactics of patient management.

Bladder leiomyoma is a rare benign bladder tumor. Our clinical observation presents a bladder leiomyoma with symptoms of urinary tract obstruction of a 40-year-old woman who came to the outpatient department with complaints of blood in the urine, discomfort in the area of the bosom articulation, and general malaise. She was examined by a urologist and referred for additional examination (ultrasound, MRI with intravenous contrasting). According to magnetic resonance characteristics, this pathologic formation has hypointense signal on T1 and T2 IP, with signal restriction at DWI, with active accumulation of contrast agent. Transurethral resection of bladder tumor is the main method of treatment of small endovesical tumors.