Inclusion Criteria:  Adult patients with simple kidney cyst Bosniak 1-2 Normal blood creatinine values  Exclusion Criteria:  Impossibility of performing CT with intravenous contrast enhancement. Bosniak 3-4 CKD Bilateral cysts Multiple renal cysts Sinus cysts Cysts with a max size less than 2 cm. Single kidney Chronic kidney disease and conditions associated with the potential decrease of kidney function Glomerulonephritis Chronic pyelonephritis Amyloidosis Diabetes Autoimmune diseases Urolithiasis Kidney and upper urinary tract surgery Anomalies of the kidneys and upper urinary tract with impaired outflow Calcification of the renal arteries Renal artery stenosis Hypertensive nephropathy Severe concomitant diseases requiring Chemotherapy Long-term (more than 10 days) antibiotic therapy in the last month Long-term (more than 7 days) use of NSAIDs in the last month Diagnostic and therapeutic manipulations accompanied by the introduction of X-ray contrast agents Secondarily shriveled or non-functioning kidney Kidney hypoplasia Accessory kidney a decrease in GFR below normal values for a kidney without a cyst (as determined by nephroscintigraphy)