Objective. To provide a rationale for using sonoelastography (SEG) in the differential diagnosis of thyroid cancer (TC).

Material and methods. Thirty patients with thyroid nodules of various morphological structures were examined. The authors studied the data of SEG and immunohistochemistry (IHC) with monoclonal antibodies against types III and IV collagen (they evaluated the degree of the expressed collagen fibers). Analysis of variance, ROC analysis, and logistic regression were used (by comparing with the expression of collagens) to assess the predictive ability of ultrasound.

Results. The study showed that irregular and uneven contours, microcalcifications, and “the height greater than the width” were most significant among the ultrasound signs in the diagnosis of TC. Cool colors prevailed when performing SEG in the pattern of thyroid cancer. Purple-blue hues were predominantly recorded (p<0.05 with regard to benign nodules), green ones were less frequently. ROC analysis of compression elastography showed that the area under the curve was 0.785 (95% CI 0.740-0.826), sensitivity 78.1%, specificity 79.0%. Comparison of the data of IHC and SEG revealed a direct correlation of tissue elasticity with the degree of a stromal component and with the presence of collagen-containing structures.

Conclusion. SEG may suppose the probable nature of thyroid nodules on the basis of their morphological features. The low degree of the stromal component and the low content of types III and IV collagen make follicular colloid goiter and adenoma soft, which is recorded at SEG. TC is characterized by a high collagen level attributable to the characteristics of the metabolism of cancer cells, which makes them solid in the mode of SEG.

Objective. To identify the scintigraphic predictors of the efficiency of interventional treatment for atrial fibrillation (AF) by cardiac ¹²³I-metaiodobenzylguanidine (¹²³I-MIBG) radionuclide scanning.

Material and methods. The investigation enrolled 35 patients with AF concurrent with hypertensive disease (HD): 17 persons with persistent AF (PAF) and 18 patients with long-standing PAF (LPAF). In addition, 10 patients with HD without arrhythmia signs were examined as a comparison group. All the patients with AF before radiofrequency ablation (RFA) and those with sinus rhythm underwent ¹²³I-MIBG myocardial scintigraphy to assess the sympathetic innervation of the heart. The efficiency of RFA was evaluated after 12 months by 24-hour ECG monitoring.

Results. The patients of both groups were divided into subgroups according to the presence of recurrent arrhythmia one year after interventional treatment. ROC analysis could determine the main scintigraphic predictors of the efficiency of RFA. The preoperative indicators, in which the subgroups with and without recurrent AF showed significant differences, were studied. In the patients with PAF, the delayed Heart/ Mediastinum (H/M) ratio cutoff was ≥1.55 (the area under the ROC curve was 0.929; 100% sensitivity and 57% specificity), and the threshold value of ¹²³I-MIBG washout rate was ≤22.3% (the area under ROC curve was 0.957; 100% sensitivity and 43% specificity) may suggest that RFA is effective. In the patients with LPAF, the threshold values of early H/M ratio were ≥1.69 (the area under the ROC curve was 0.849; 100% sensitivity and 62% specificity) and those of delayed H/M ratio were ≥1.66 (the area under the ROC curve was 0.938; 94% sensitivity and 23% specificity) allow the prediction of a risk for postoperative recurrent AF.

Conclusion. The findings suggest that ¹²³I-MIBG scintigraphy can be used to predict a high risk for recurrent AF after RFA of the pathological pathways of a pulse in the myocardium.

Objective. To enhance the reliability of visual analysis of X-ray mammograms, by applying the mathematical models of neoplasms and a method for their processing based on the mathematical apparatus of contour analysis.

Material and methods. Two data sets were generated from X-ray mammograms obtained from 38–82 year old patients at routine examinations in the Republican Oncology Dispensary. The first set contained 100 packages of X-ray mammographic images that failed to reveal abnormal malignant changes. The second set was represented by 168 packages of X-ray mammographic images showing morphologically verified breast cancer. All the packages of mammographic images are presented in the standard direct craniocaudal and mediolateral oblique projections. The images were obtained using an analog mammograph. Digital copies of images having a resolution of 600 dpi were obtained for subsequent computer processing. The latter of digital mammographic images involved segmentation of space-occupying lesions, determination of the linearity factor of their outlines, and differential diagnosis of space-occupying lesions based on the calculated value of the linearity factor of their outlines.

Results. An algorithm was elaborated for identifying the outlines of space-occupying lesions on X-ray mammographic images. The sequence of complex-valued vectors approximating its curve was used as a mathematical model of the outline. The concept on the outline linearity factor, which quantitatively characterizes its shape, was introduced. A method was developed for the objective classification of malignant and benign space-occupying lesions based on the value of the introduced linearity factor. The outlines of benign space-occupying lesions in the breast were ascertained to be characterized by the higher linearity factor (in the region of 0.3–0.4) (BI-RADS category 2), while the outlines of malignant tumors had a much lower value of this factor (in the order of 0.05–0.1) (BI-RADS categories 4–5). The main quantitative measures (sensitivity, specificity, and accuracy) of the informative value of the proposed method were determined. The latter was shown to have a higher specificity than the traditional visual analysis carried out by a radiologist. This allows the proposed method to be used as an additional procedure in the visual analysis of mammograms to enhance the reliability of clinical findings.

Conclusion. The practical value of the method is in quantitatively evaluating the shapes of malignant breast neoplasms, in reducing the performance of a mammographic examination, and in increasing its objectivity. The proposed method makes it possible to reduce the time of analyzing X-ray mammograms and to enhance the reliability of clinical findings.

Objective. To determine the most effective irradiation regimen (total dose and dose per fraction) for hypofractionated treatment for prostate carcinomas according the TCP/NTCP radiobiological criteria.

Material and methods. Using the tomographic information of five patients with low-risk prostate adenocarcinoma as an example, the authors devised dosimetric radiation therapy plans using the volumetric modulated arc therapy (VMAT) procedure. They considered the range of total doses of 33.5 to 38 Gy administered in 4 and 5 fractions. Based on the equivalent uniform dose concept proposed by A. Niemierko and on the computed differential dose volume histograms, the investigators modeled local tumor control probability (TCP) values, by taking into account the uncertainties of main radiobiological parameters, and estimated normal tissue complication probabilities (NTCP) for the anterior rectal wall as the organ most at risk of irradiation. An effective dosimetric plan was selected according to the UTCP criterion and the probability of complication-free tumor control, i.e. TCP (1 – NTCP).

Results. The results of modeling the UTCP criterion show that with a higher total dose, the TCP value increases and so does the NTCP value, therefore the optimal radiation therapy plans are to irradiate with a total dose of 34 Gy over 4 fractions or with a dose of 36–37 Gy over 5 fractions. The difference between the fractionation regimens is that the UTCP value is achieved with a higher TCP value over 4 fractions and with a lower load on the rectal wall over 5 fractions.

Conclusion. The choice of a specific fractionation regimen should be determined from the calculated values of differential dose volume histograms for each patient, as well as from radiobiological criteria, such as TCP, NTCP and UTCP.

Objective. To compare bone mineral density (BMD) values derived during one-year asynchronous quantitative computed tomography (QCT) in two urban polyclinics (UPs).

Material and methods. The investigation enrolled women aged 40 to 85 years: 694 and 724 patients in UP А and UP B, respectively, who underwent QCT scanning of the proximal femur and spine. The BMD values were compared with the reference data embedded in the QCP software, by using the methods of regression analysis. Quantitative indicators were calculated using the Z-test. To standardize the indicators of QCT in UP A and UP B, cross-calibration was performed using a phantom.

Results. Comparison of the obtained mean BMD values with the reference one for three regions of central densitometry established a statistically significant (p<0.05) decrease in the mean BMD values relative to the normative ones within the analyzed age range. The spine Z scores were  – 0.37 SD in UP А and  – 0.84 SD in UP B; the mean proximal femur Z scores were  – 0.70 SD and  – 1.22 SD in UP А and UP B, respectively; the mean femoral neck Z scores were  – 0.54 SD and  – 1.06 SD, respectively. The values of femoral neck and proximal femur BMD displayed pronounced correlations (r=0.83 in UP А and r=0.79 in UP B). Comparison of regression line coefficients in the proximal femur and spine regions revealed that the offset of a straight line was significantly lower in UP B than in UP А (p<0.05). There were no differences in the slope coefficients for these regions. The results of comparing the regression lines for the femoral neck were statistically insignificant for both the slope coefficient (p=0.576) and for the offset (p=0.056).

Conclusion. Comparison of the authors' own results of the BMD study with the reference data has shown a statistically significant decrease in the obtained BMD values in two UPs. This may be associated with the different strategy of referral for QCT, as well as with some assumptions of this study.

Objectives. (1) To evaluate the efficiency of work of the Department of Computed Tomography (CT) and Magnetic Resonance Imaging (MRI); (2) to study of its work processes; and (3) to elaborate recommendations for their optimization.

Material and methods. Using the principles of lean manufacturing and the original methodology of the Philips Co., the investigators made a comprehensive assessment of the work of the Tomography Department, Center for Radiation Diagnosis, Treatment and Rehabilitation, Ministry of Health of the Russian Federation, in December 2016 to February 2017, including: (1) a study of management reports; (2) oral interviews of employees; (3) a survey of employees, by using a specially designed questionnaire; (4) direct observation and subsequent description of work processes; and (5) assessment of patient satisfaction, by calculating the net promoter score. Based on the findings, the investigators calculated the throughput potential of CT and MRI, described the factors influencing the possibility of realizing this potential, developed recommendations to enhance the efficiency of work processes, and ranked the latter by the magnitude of the expected effect, by the complexity of implementation, and by material costs, followed by prioritization.

Results. Assessment of the throughput potential has shown that CT and MRI examinations can be performed by 50.6% and 23.2% more, respectively. This can be achieved by additionally attracting patients, reducing equipment downtime, optimizing work processes, most of all at the stage of patient recording and registration, as well as at the stage of image interpretation and creation of a conclusion. The developed recommendations for optimizing work processes included measures of varying effectiveness and complexity, which could rank them according to three priority levels and identify long-term strategic initiatives.

Conclusion. The comprehensive study of the efficiency of work of the Departments of CT and MRI made it possible to quantify the potential for increasing the throughput of CT and MRI, to consider in detail the stages of a medical service delivery process, to reveal areas for improving the process, and to form a set of recommendations for their optimization.

Objective. To compare the informative value of using dynamic magnetic resonance imaging (MRI) and diffusion-weighted MRI (DW-MRI) in patients with breast liver metastasis during chemotherapy.

Material and methods. The investigation enrolled 30 patients with breast liver metastasis during their treatment. The results of standard intravenous contrast-enhanced abdominal MRI studies (by evaluating the liver in the arterial, venous, and delayed phases) were compared with those of DW-MRI with different B-factor values (50, 400 and 800 sec/mm²).

Results. Comparison of the findings of initial studies prior to chemotherapy (those of only dynamic intravenous contrast-enhanced MRI and only DW-MRI) revealed a complete correspondence with the number of detected foci in 10 patients. Ten patients had a larger number of metastatic foci at DW-MRI than at intravenous contrast-enhanced MRI, in the aggregate by 44 foci more (of them 36 foci measured less than 1 cm). The remaining 10 of the 30 patients were found to have multiple, unquantifiable (more than 20–40) metastatic foci of various sizes (1–6 cm) at both intravenous contrast-enhanced MRI and DW-MRI. Nineteen of the 30 patients were followed up during their chemotherapy. Seven of the 19 patients showed a stabilized liver metastatic process that was similarly evidenced by both techniques. Eleven of the 19 patients were observed to have a progressive metastatic process that was reflected by the similar increase in the number and size of metastases in 5 of the 11 patients, as shown by both of the above techniques. In the remaining 6 of the 11 patients, the number of newly detected liver tumors proved to be larger at DW-MRI than at intravenous contrast-enhanced MRI. Both techniques showed that the last patient of the 19 cases had a decrease in the number of small liver metastases that maintained their sizes (less than 1 cm).

Conclusion. DW-MRI has been shown to be much more effective in detecting metastases than conventional intravenous contrast-enhanced MRI, which necessitates the inclusion of this technique in standard abdominal MRI protocols for patients with liver metastasis.

Objective. To evaluate the efficiency of magnetic resonance spectroscopy in the diagnosis and prognosis of breast cancer (BC).

Material and methods. Twenty-eight patients aged 37 to 80 years with established primary invasive BC were examined. Its grade was determined according to pathomorphological verification with immunohistochemical analysis. Breast MRI was performed using the standard protocol, by determining the measured diffusion coefficient (MDC), dynamic contrast enhancement (DCE). Proton magnetic resonance spectroscopy was carried out using the Breeze software package. The clinical and morphological findings and the results of radiation studies were compared to determine Nottingham prognostic index (NPI) scores. To identify the Spearman rank correlation coefficient between MRI findings (the type of pharmacokinetic curves, the total choline-containing (tCho) peak integral) and the values characterizing tumor size and grade.

Results. NPI calculation showed that the scoring range was 2.4 to 6.76; the expected 5-year survival rates reached 93%. The mean MDC was 0.856×10^-3 mm²/sec; type II pharmacokinetic curve prevailed (n=16; 57.1%). There was a statistically significant negative correlation between the values of MDC, the type of a contrast agent accumulation curve, the levels of HER2/neu and the proliferation marker Ki-67; there was a statistically significant strong positive correlation between the presence of ¹H-MPC tCho peak and the indicators determining tumor malignancy (the levels of HER2/neu and Ki-67). Statistically significant differences between the type of a pharmacokinetic curve in DCE and the level of tCho in the prognostic groups defined when calculating NPI were determined in patients with moderate (n=4; 14.2%) and poor (n=10; 35.7%) prognosis.

Conclusion. The capabilities of MR spectroscopy are superior in information content to the data obtained by determining the MDC, the nature of contrast medium accumulation in breast tumor, and are comparable with the data determining the type of a tumor (the presence of the HER2/neu gene, Ki-67 proliferation marker) in predicting BC cancer grade and 5-year survival rates.

Objective. To increase the efficiency of diagnosis and estimation of the local extent of a tumor process in cervical cancer (CC) using all modalities of multiparametric magnetic resonance imaging (mpMRI).

Subjects and methods. Examinations were made in 31 patients (mean age 45±11 years) with histologically verified minimally invasive CC, who underwent surgical treatment. The investigators used the following modalities: T2 weighted imaging (T2WI); T2WI with fat signal suppression; diffusion-weighted image (DWI) with apparent diffusion coefficient (ADC) mapping; T1WI with dynamic contrast-enhanced MRI (DCE-MRI).

Results. The measured distances significantly differed from the true ones obtained from the morphological findings (p<0.05). With allowance made for the built linear regression models, the investigators generated correction formulas. The best modality of MRI in establishing the presence of parametrial invasion in CC and in measuring the actual depth of invasion was T1WI with DCE-MRI (using the images obtained 100–125 seconds after MRI contrast medium administration); the slightly worse modality was DWI with ADC mapping (with a specificity of 91%, the sensitivities of DCE-MRI and DWI with ADC mapping were 95% and 90%, respectively), and T2WI with and without fat signal suppression.

Conclusion. Quantitative analysis of the extent of CC in the parametrium according to the results of complex mpMRI seems to be a possible and highly accurate method.

The review presents a rare clinical case of right-sided infective endocarditis (IE), a variant of early diagnosis using contrast-enhanced multispiral computed tomography (CE-MSCT), and successful surgical treatment for septic pulmonary embolism and right-sided IE. The clinical manifestation of the disease lasted about 3 weeks. The diagnosis was established according to the results of an emergency complex CE-MSCT study. At 4 hours after the patient went to the clinic, a combined operation (removal of part of the venous port and thrombectomy from the left pulmonary branch) was successfully performed. There was a complete coincidence of CE-MSCT study data and intraoperative results; staphylococcal septic focus was confirmed in a laboratory. The total length of stay in hospital was 9 days; that of full performance restoration was 3 weeks. The presented case has proven that the CE-MSCT may be the only sufficient technique for detecting septic pulmonary embolism and deciding in favor of surgical treatment, eliminating the need for a different kind of instrumental diagnosis, which significantly reduces the time of diagnosis.