[Dual-energy computed tomography in the diagnostics of urolithiasis].

THE AIM: To assess the diagnostic performance of dual-energy computed tomography (DECT) in the evaluation of the composition of urinary stones "in vivo". MATERIALS AND METHODS: A total of 91 patients aged from 20 to 70 years old (mean 42.7) with urinary stone disease were examined at Sechenov University, including 68 men (75%) and 23 women (25%). Prior to surgery, all patients underwent DECT (Canon, Japan) in order to predict the chemical composition of urinary stones in vivo. Extracorporeal shockwave lithotripsy (ESWL), percutaneous nephrolithotomy (PCNL) and ureteroscopy (URS) was performed in 53 (58.2%), 18 (19.7%) and 20 (22.1%) patients, respectively. Postoperatively, all stones or stone fragments (n=91; 100%) were examined using a comprehensive physical and chemical analysis (X-ray phase analysis, electron microscopy, infrared spectroscopy). RESULTS: In 6 patients (6.6%) staghorn stones were diagnosed, while in 15 (16.5%), 17 (18.7%), 22 (24.2%) and 31 (34.1%) stones were located in ureteropelvic junction, pelvis and ureter, respectively, including 24 patients with lower ureteric stones (26.4%). Prediction of the stone composition in vivo was carried out on the basis of the one indicator, the dual energy ratio (DER). The threshold values of DER for different types of stones were taken from the literature. All stones were divided into 4 groups according to the DECT results: vevellite stones (n=40, 43.9%), Ca-containing stones without vevellite (n=34, 37.3%), uric acid stones (n=10, 10.9%) and struvite stones (n=7, 7.9%). Thus, when comparing the results of DECT and physical and chemical analysis, in the first group four stones were incorrectly assigned by DECT to the group of Ca-containing stones without vevellite and three stones were incorrectly assigned to the group of struvite stones; in the second group four stones were incorrectly assigned to the group of vevellite stones; in the third group one stone was incorrectly assigned to the group of struvite stones; in the fourth group one stone was incorrectly assigned to the group of vevellite stones and one stone in the group of uric acid stones. In order to increase the diagnostic efficiency of DECT, we performed a comprehensive analysis of five specific DECT indicators (stone density at 135 kV, Z eff of the stone, DER, DEI, DED) using discriminant analysis. Thus, the sensitivity, specificity and overall accuracy of DECT with the use of just one indicator (DER) were 83.3%, 89.8%, 86.8% for vevellite, 88.2%, 92.9%, 91.2% for Ca-containing stones without vevellite, 90%, 98.8%, 97.8% for uric acid stones and 60%, 95.3%, 93.4% for struvite stones, respectively. When using discriminant analysis with five specific DECT indicators, higher values of sensitivity, specificity and overall accuracy were seen: 95.2%, 89.8%, 92.3% for a vevellite, 85,3%, 96,4%, 92,3% for Ca-containing stones without a vevellite and 100%, 100% and 100% for both uric acid and struvite stones, respectively. CONCLUSIONS: Dual-energy computed tomography is a highly informative method which allows to perform preoperatively the reliable assessment of the chemical composition. DECT in patients with urinary stone disease allows to optimize the treatment strategy and carry out preventive measures on individual basis, taking into account the stone type.

[Clinical value of CT-perfusion in patients with ureteric stones].

INTRODUCTION: Urinary stone disease is one of the most significant urologic diseases, since its prevalence increases annually, which makes it necessary to study and improve effective preventive measures, diagnostic methods and to implement new treatment interventions. AIM: to study changes in blood flow in the renal cortex and medulla in patients with ureteral stones using CT perfusion. MATERIALS AND METHODS: From 2017 to 2019, a total of 53 patients with upper ureteric stones were evaluated at the Russian-Japanese Center for Imaging and the Institute of Urology and Reproductive Health of the FGAOU VO I.M. Sechenov First Moscow State Medical University. Preoperatively, all patients underwent CT perfusion. The study was performed on a Toshiba Aquilion One 640 in volume mode with a slice thickness of 0.5 mm. In this study, blood flow changes were evaluated depending on the degree of dilatation of collecting system. RESULTS: In patients without dilatation of the collecting system, the average values of cortical and medullary blood flow and blood volume were within normal values. In patients with a dilatation of collecting system, there were significant differences cortical and medullary blood flow between the affected renal unit and contralateral side (27% and 34%, respectively). A decrease in cortical and medullar perfusion by 55% and 58%, respectively, in patients with the dilatation of calyxes was more pronounced in comparison with a decrease in perfusion in patients with the dilatation of only the ureter and pelvis. CONCLUSION: CT perfusion performed on the 640-slice CT scan allows an objective assessment of changes in renal blood flow in patients with ureteric stones.

[Modern radiology diagnostics methods for assessment of renal perfusion in patients with urinary stone disease].

Urinary stone disease is the current issue for healthcare system worldwide. High prevalence of urinary stone disease (at least 5% of the population of developed countries) determines clinical significance of the studying of its etiology and pathogenesis, improving of diagnostic methods and novel treatment technologies. The development of endoscopic devices, creation of new eswl machines and improvement of endourology interventions under X-ray guidance allowed to solve the problem of surgical treatment. Therefore, one of the actual issue is the choice of X-ray method for predicting and evaluating of treatment efficiency in patients with urinary stone disease. The changes of renal blood flow depend on urodynamic disturbances, stone location and size, the duration of disease, complications, patients age. Therefore, for comprehensive studying of renal function the hemodynamics evaluation is needed. In this review the advantages, drawbacks and perspective on developing of different radiologic methods for renal hemodynamic assessment are given.

[Clinical implications of dual-energy computed tomography in the diagnosis and treatment of urolithiasis].

Urolithiasis (urolithiasis) is one of the most common urologic diseases with an estimated prevalence of no less than 3% in the population, usually affecting active working-age patients of 30-50 years. Taking into account major public health and economic significance of this problem, there is the need for the development of effective modern diagnostic techniques. Rapid medical-technological advances of the past two decades have led to the wide spread use of minimally invasive surgery the management of urolithiasis. Nevertheless, surgical intervention only removes the result of a long pathological process and does not change its course. Thus, there is a need for a detailed understanding of the etiology, epidemiology, and pathogenesis of urolithiasis. Diagnostic imaging plays a key role in the diagnosis of urolithiasis. Multislice spiral computed tomography (MSCT) is the gold standard for the diagnosis of urolithiasis. It provides information about the size, location, and density of the calculus. Over the past decade, the use of dual-energy computed tomography (DECT) in urological practice has been widely discussed in the international and domestic literature. One of the main advantages of DECT is the ability to determine the chemical composition of urinary stones. Previous studies have reported a high diagnostic value of the method, including the ability to predict treatment outcomes. However, the shortcomings of the method and the absence of standardized examination protocols leave a wide field for further research. This article reviews major distinctive features of using DECT in the diagnosis of urolithiasis.