Clinical Study Of Glomerular Filtration Rate Measured By Using Multi-phasic Helical CT

Part one: Glomerular filtration rate measured on multi-phasicHelical CTPurpose:To investigate a new technique for measuring glomerular filtration rate (GFR) on multi-phasic Helical CT and evaluate the accuracy.Methods: Thirty adult patients without acute renal disorder and history of hypertension and diabetes were included in this study. Each patient underwent CT for clinical indications. The CT protocol consisted of an unenhanced scan and three contrast-enhanced scans 28, 61, and 94 sec after starting an injection of 90 ml of iohexol (300mgIml) using an injection rate of 3 ml/sec. All scans included both kidneys. Glomerular filtration rate was calculated with a Patlak plot technique, As a reference , Cystatin C was determined in 30 blood specimens.Result: CT clearance was calculated two times for each patient, including early CT clearance, 28-61 sec postinjection; late CT clearance, 28-94 sec postinjection. An early CT clearance yielded the best correlation with Cystatin C with a correlation coefficient of r=0.75 and a regression line of y=37.4723 + 0.6370 x.Conclusion: GFR can be measured accurately with minimally extended multi-phasic CT for patients without acute renal disorder .Part two: Application of glomerular filtration rate measured byusing dual-phase Helical CTPurpose: To investigate a new technique for measuring glomerular filtration rate on dual-phase Helical CT and its accuracy, and to evaluate the value of using soft UroCARE for determining GFR.Methods: Twenty-five adult patients without acute renal disorder were included in this study. Each patient underwent CT for clinical indications. The CT protocol consisted of a plain examination followed by two contrast material-enhanced examinations in the arterial and portovenous phase. Each examination included the entire kidneys and was performed after injection of 90 ml iohexol (300mgIml) of using an injection rate of 3 ml/sec. CT clearance was calculated by using soft UroCARE . As a reference ,Cystatin C was determined in 25 blood specimens.Result: Linear regression analysis show that tile two groups GFR had very well associativity, the correlation coefficient of whole kidney was r=0.80 and a regression line of y= 39.0977+0.6083 x.Conclusion: GFR can be measured accurately with minimally extended dual-phasic CT for patients without acute renal disorder.It is reliable in clinical practice by using soft UroCARE for determining GFR.