Relevance: Radionuclide bone scan signs of lesions are not specific and require radiological identification. Hybrid tomographic technology is a combination of spatial distribution of radiopharmaceuticals and its anatomical binding. Thus, makes it possible to accurately identify the affected bone structure and also determine the nature of this changes (radiological anatomy). In cancer patients, SPECT/CT method allows to visualize tumor pathology in the bones, but also keeps to a minimum errors and other excessive examinations.

Purpose: To demonstrate the most frequent diseases and conditions that simulate tumor lesions in bones on bone scan.

Material and methods: We analyzed the results of examinations of 81 patients with various tumor diseases (2015–2020). Bone scan was performed in the whole body 3 hours later, after intravenous administration of 99mTc-phosphotech on a Symbia E, T2 (Siemens, Germany). SPECT/CT was performed after WB Bone Scan.

Results: The most frequent reasons for the focal increased uptake of radiopharmaceutical were: reactive increase in metabolism and as a result additional mineral repair: deforming osteoarthritis, osteophytes; post‑traumatic and postoperative changes; fractures (osteoporosis and stress fractures); inflammatory processes; focal uptake due to the benign neoplasms of bones and dysplasia. Combination of highly sensitive but non-specific scintigraphy with highly specific computed tomography makes it especially useful in anatomically difficult areas.

Conclusion: SPECT/CT reveals a direct pater of anatomical and structural abnormalities with changes in bone tissue metabolism in case of different injuries and minimizes a number of ambiguous conclusions. SPECT/CT in oncological practice greatly helps nuclear medicine physician in the differential diagnostic process and reduces time of examination for the patient. 

Purpose: To evaluate the prognostic factors in patients with Breslow skin melanoma of various thicknesses that affect the incidence of metastases in the signal lymph nodes (SLN).

Material and methods: From November 2018 to November 2020, 324 patients with diagnosed melanoma of the skin of various localization and stages were examined and operated on. We used lymphotropic colloidal radiopharmaceutical (RPh) labeled with 99mTc. RPh with an activity of 150 MBq was administered one day before the operation intradermally around the scar of resected melanoma or peritumorally at 4 points in the case of a primary tumor. Lymphoscintigraphy was performed 1–3 hours after the RP injection on a Symbia E or Symbia E gamma camera (Siemens, Germany). Anteroposterior and lateral static polypositional scintigraphy was performed to determine the topography and mark the SLN. 324 planar studies were performed. In 259 cases, an additional study was performed SPECT (including SPECT / CT) on a Symbia T2 device (Siemens, Germany). Surgical intervention was performed the next day, taking into account the data of intraoperative radiometry using a domestic specialized hand-held gamma detector Radical (Amplituda, Russia).

Results: The mean primary melanoma Breslow thickness was 2.77 ± 2.2 mm (range 0.2–13.0 mm). Localization of SLN: axillary (n = 161. 51 %), inguinal (n = 100. 31 %), cervical (n = 16. 5 %), submandibular (n = 9. 3 %), supraclavicular (n = 4. 1 %), more than one basin (n = 34. 9 %). In the group of melanomas <0.75 mm thick, no SLN metastases were found, among 0.75–1 mm melanomas, one positive lymph node with metastasis (SLN+) was found, in the largest group of melanomas of medium thickness (1–3.5 mm) — 25 (17 %). The largest percentage of metastases in SLN is determined in thick melanomas (>3.5 mm) — 17 (28 %), which is consistent with the data of foreign literature, while SLN is most often affected with a Breslow tumor thickness of more than 7 mm.

In the group with negative sentinel lymph nodes (SLN–), the average tumor thickness according to Breslow was 2.6 ± 2.0 mm, in the SLN+ group — 4.0 ± 2.9 mm, the differences between the groups are statistically significant, which is confirmed by the result of one-way analysis of variance.

The optimal threshold value of tumor thickness according to Breslow for the isolation of patients with a positive prognosis of metastasis in the SLN is 2.0 mm. It is characterized by the maximum levels of sensitivity (79 %) and specificity (59.1 %). An older age of patients (over 35 years old) is also associated with an increased incidence of metastases in the SLN, but this indicator is not statistically significant. Most often, SLN metastases were detected when the primary tumor was localized in the back (more often in men) and lower extremities (more often in women), while they are thicker (> 3.5 mm).

Conclusion: 1. According to the ROC-analysis, the optimal threshold value of the tumor thickness according to Breslow for the isolation of patients with a positive prognosis of metastasis in the SLN is 2.0 mm. It is characterized by the maximum levels of sensitivity (79 %) and specificity (59.1 %). 2. Statistically significant prognostic factors of metastasis in SLN: localization of the primary tumor in the back (more often in men) and lower extremities (more often in women); Breslow thickness over 3.5 mm. 3. The absence of the influence of gender and age was noted, with a slight predominance of women in both groups. 

Purpose: To assess the effectiveness of a new method of contrast-enhanced ultrasound examination (CEUS) for determining the duration of the arterial phase of contrasting liver, kidney and spleen.

Material and methods: We examined 37 patients with a verified diagnosis of viral alcoholic hepatitis with splenomegaly syndrome (n = 11), chronic hepatitis B (n = 14) and diabetic nephropathy against the background of type 2 diabetes (n = 12). The age of the examined patients was 39–56 years. Patients with diabetic nephropathy underwent complex diagnostics, including ultrasound examination of internal organs in B-mode with further Doppler assessment of the hemodynamics in the vessels of the kidneys. Patients with chronic viral hepatitis B and alcoholic hepatitis underwent a multiparametric ultrasound complex of examination, supplemented by strain elastography (SE). Further, a contrast-enhanced ultrasound examination (CEUS) of the kidneys was carried out using an echocontrast agent SonoVue in doses recommended for each organ, followed by an assessment of the arterial phase according to the standard and proposed method.

Results: While interpreting the data of the liver study in patients with chronic viral hepatitis B according to the standard method, quantitative data were obtained for the duration of the arterial phase of 16.4 ± 15.7 sec, and according to the proposed method, 12.1 ± 8.3 sec. In patients with alcoholic hepatitis with splenomegaly syndrome, the CEUS values are 21.8 ± 16.9, 17.3 ± 12.8 sec, in patients with diabetic nephropathy, — 13.5 ± 9.5 and 10.5 ± 5.9 sec accordingly. The results obtained, together with clinical and laboratory indicators can be interpreted in favor of improving the dynamics. Knowing the approximate data on the duration of the arterial phase during for the liver (from 8–14 to 40 sec), for the kidney (10–20 to 25–35 sec), for the spleen (8–60 sec), it can be concluded that the proposed method for determining the time of the onset of the arterial phase during CEUS is more accurate, since it allows one to determine the presence of diffuse pathology of organs at the microcirculatory level.

Conclusion: 1. The exact values of the onset of the arterial phase of contrasting were determined, thereby increasing the importance of CEUS in the diagnosis of diffuse pathology of the liver, kidneys and spleen. 2. The proposed method for determining the flow time of the arterial phase of echocontrast agent allows monitoring the effectiveness of treatment of diffuse pathology of the kidneys, spleen and liver (Patent RU No. 2744825). 

Purpose: To compare the capabilities and evaluate the effectiveness of gray-scale B-mode, Doppler mapping and contrast enhanced in the assessment of cystic renal lesions.

Material and methods: Ultrasound examination (US) was performed in 61 patients with cystic kidney formations (category Bosniak ≥ II). Cysts of categories Bosniak ≥ III were histologically verified, rest (categories II–IIF) were under follow up. All patients underwent gray-scale ultrasound, color Doppler imaging and contrast enhanced (CEUS).

Results: The efficiency of the B mode was: sensitivity 55.6 %; specificity 72.1 %; accuracy 62.3 %, in the CDI mode these indicators were 52.8; 80.1; 63.9 %, respectively. Contrast ultrasound significantly increased the capabilities of the method, and also made it possible to evaluate cystic formations according to the Bosniak criteria with indicators of the effectiveness of the method up to 100.0; 92.0; 96.7 %, respectively.

Conclusions: CEUS demonstrated high informative value in the assessment of renal cystic formations in comparison with native ultrasound and Doppler modes, and therefore the technique should be considered as promising for inclusion in the algorithm of examination of complex renal cysts. 

Purpose: To evaluate contrast-enhanced magnetic resonance imaging (CE‑MRI) and diffusion-weighted (DWI) in the detection and differential diagnosis of recurrent of retroperitoneal liposarcomas with postoperative changes.

Material and methods: The retrospective study included of 23 patients previously operated on for retroperitoneal inorganic liposarcomas. All patients underwent MRI of the abdominal cavity and pelvis with intravenous contrast with further assessment of the size, shape, structure and characteristics of the accumulation of contrast agent in the detected formation.

Results: Morphological verification were performed in 17 patients (74 %), in 6 cases (26 %) patients were left for dynamic control for 1–3 years. Local relapses were detected in 16 patients (67 %), postoperative changes — in 7 (33 %) patients, of which in 2 cases deformation of adipose tissue and fibrotic changes in the area of surgery was determined, in 3 patients granulomas were revealed, and in two patients — volvulus of the greater omentum and lymphocele. The sensitivity of MRI with intravenous contrast enhancement was 68.7 %, specificity 71.4 % and accuracy 69.6 %. The addition of DWI to the standard MRI protocol in patients with suspected recurrence of retroperitoneal liposarcoma to increase the sensitivity of the method in the differential diagnosis of recurrent drugs from postoperative changes to 93.7 % (15 out of 16), specificity up to 100 % (7 out of 7) and accuracy up to 95.6 % (22 out of 23).

Conclusion: The joint use of MRI with intravenous contrast and DW‑MRI increases the information content in the detection and differential diagnosis of small-sized recurrent tumors in dedifferentiated and myxoid types of liposarcomas with postoperative changes. 

Purpose: Тo determine the possibilities of quantitative assessment of mpMRI with EOB-DTPA in the differential diagnosis of benign and malignant tumors in children.

Material and methods: 30 patients (male — 17, female — 13) with 83 tumors underwent MRI. Age ranged from 5 months to 20 years. All children underwent MRI on 3T or 1.5T MR-scanners using body coil. Fat saturated T1WI were performed before and after hepatotropic MR-contrast agent (gadoxetic acid) injection in arterial, portal, venous and delayed phases (1, 5, 20, 40 min). Tumors were divided into 2 groups: benign (52) and malignant (31). In this work we use only pre- and postcontrast T1WI. Diagnosis was confirmed histologically (all malignant and a part of benign FLL) and long-term MRI follow-up studies (for benign). To eliminate influence of external factors we used coefficients for each MR-program, the signal was normalized to intact liver parenchyma, spleen, abdominal aorta and v. cava inferior, also normalization to native series has been performed. Coefficients were compared for malignant and benign tumors using Student’s t-test, significantly different parameters were further used to build mathematical model by constructing a logistic regression with step-by-step selection of the most informative values.

Results: Regression model is presented by formula. The model is informative and statistically significant (p < 0.001). If A>0.5 tumors has a malignant nature if А ≤ 0.5–benign. Model sensitivity and specificity are 0.862 and 0.925, respectively.

Conclusion: Our model could be an excellent assistance in differentiation of benign and malignant focal liver lesions and reduces diagnostic path, effects the proper patients management. 

Relevance: Differential diagnosis of focal formations of the pancreas is particularly difficult due to the similarity of their echosemiotics. One of the ways to objectify and improve the accuracy of ultrasound data is to use artificial intelligence methods to interpret images.

Purpose: Improving the quality of diagnosis of focal pancreatic pathology according to endoscopic ultrasonography based on the analysis of the echographic texture using fuzzy mathematical models.

Material and methods: In the Kursk Regional Clinical Hospital, endoscopic ultrasonography was performed in 272 patients for pancreaticobiliary diseases. The endoscopic video system of the company Olympus EVIS EXERA II with the ultrasonic processor EU-ME1 was used. Solid tumors of the pancreas were detected in 109 (40.1 %) patients, focal pancreatic masses were diagnosed in 40 (14.7 %) patients. Based on the research results, the main types of reference endosonograms corresponding to differentiable pathology were identified. On the basis of endosonograms, using hybrid fuzzy mathematical decision rul, a fuzzy hybrid model of differential diagnosis of chronic focal pancreatitis and ductal adenocarcinoma of the pancreas was obtained.

Results: The selected source of information and the method of synthesis of hybrid fuzzy decision rules made it possible to obtain a fuzzy hybrid model of differential diagnosis of chronic focal pancreatitis and ductal adenocarcinoma of the pancreas. Based on the results of mathematical modeling and statistical tests on representative control samples, it was shown that the resulting model of differential diagnosis, using reference endosonograms reflecting the echographic texture of focal pancreatic masses, provides confidence in the desired diagnosis at the level of 0.6. The additional information used in the analysis of endosonograms increases the diagnostic confidence to a value of 0.9.

Conclusions: The resulting model of differential diagnosis of chronic focal pancreatitis and ductal adenocarcinoma of the pancreas provides confidence in decision-making no worse than 0.9, which is an acceptable quality indicator in clinical practice in conditions of insufficient statistics with poorly formalized data structure. 

A dictionary of abbreviations (abbreviations), most often used in scientific publications, methodological recommendations, regulatory documents on the medical use of sources of ionizing radiation, has been developed. The dictionary contains abbreviations in English, which are usually not deciphered in English-language publications, as well as abbreviations in Russian with the reduction, if possible, of the corresponding English abbreviations. The dictionary is intended for use both in professional education, including postgraduate education, and to facilitate the interaction of medical physicists, radiologists, radiologists and radiation oncologists working in radiological and oncological medical organizations. 

Intracranial hypotension is a clinical and radiological syndrome, manifested by a decrease in the volume or pressure of the cerebrospinal fluid caused by various reasons, one of the main clinical manifestations of which are orthostatic headaches. The gold standard in the radiation diagnosis of this condition is magnetic resonance imaging (MRI). Increasing the awareness of radiologists about this pathology, its manifestations on MRI, will allow more often to diagnose this syndrome and choose the tactics of further treatment. This publication presents its own clinical observation — a patient with intracranial hypotension syndrome, on his example, MR and clinical manifestations are considered, and some data on the etiology and pathogenetic mechanisms of the described pathological process are also given. 

Purpose: Assessment of the capabilities of the ultrasound method in the diagnostics of a rare Hurthle-cell tumor of the thyroid gland on the example of a clinical case of a patient with malignant neoplasms of independent primary multiple localizations in comparison with other research methods.

Material and methods: A comprehensive study of materials from the history of the disease, the results of clinical, laboratory, instrumental, morphological research methods and their comparison with diagnostic cases from literature data.

Results: Despite the full comprehensive examination of the patient, including ultrasound, MRI, PET/CT, puncture biopsy under ultrasound control, it was not possible to make the correct diagnosis before the operation. The presence of other malignant diseases in the patient’s history, the presence of altered paratracheal nodes in the same zone, and the rare occurrence of Hurthle thyroid tumors played a role.

Conclusions: Hurthle-thyroid cell tumors are a rare disease, but it must always be taken into account in the diagnostic search, since even benign Hurthle tumors have a high risk of malignancy and spreading of distant metastases.