Renal parenchyma thickness: a rapid estimation of renal function on computed tomography

Abstract

Purpose: To define the relationship between renal parenchyma thickness (RPT) on computed tomography and renal function on nuclear renography in chronically obstructed renal units (ORUs) and to define a minimal thickness ratio associated with adequate function. Materials and Methods: Twenty-eight consecutive patients undergoing both nuclear renography and CT during a six-month period between 2004 and 2006 were included. All patients that had a diagnosis of unilateral obstruction were included for analysis. RPT was measured in the following manner: The parenchyma thickness at three discrete levels of each kidney was measured using calipers on a CT workstation. The mean of these three measurements was defined as RPT. The renal parenchyma thickness ratio of the ORUs and non-obstructed renal unit (NORUs) was calculated and this was compared to the observed function on Mag-3 lasix Renogram. Results: A total of 28 patients were evaluated. Mean parenchyma thickness was 1.82 cm and 2.25 cm in the ORUs and NORUs, respectively. The mean relative renal function of ORUs was 39%. Linear regression analysis comparing renogram function to RPT ratio revealed a correlation coefficient of 0.48 (p < 0.001). The linear regression equation was computed as Renal Function = 0.48 + 0.80 * RPT ratio. A thickness ratio of 0.68 correlated with 20% renal function. Conclusion: RPT on computed tomography appears to be a powerful predictor of relative renal function in ORUs. Assessment of RPT is a useful and readily available clinical tool for surgical decision making (renal salvage therapy versus nephrectomy) in patients with ORUs.

Parenchymal Thickness: Does It Have an Impact on Outcomes of Percutaneous Nephrolithotomy?

“…The RPT is accepted as an indicator of relative renal function in chronic obstructive renal disease and an independent variable to predict the recoverability of renal function after resolution of the obstruction [13,14,15,16,17]. The size and thickness of the kidney are affected by various congenital and acquired conditions and age.…”

Change of Renal Parenchymal Width in Patients with Unilateral Ureteral Stent: A Bicenter Retrospective Study

“…Third, renal PW on CT scan appears to be able to predict relative renal function. In a study where renal parenchymal thickness ratio is compared to Mag-3 Lasix renogram [14], renal PW on CT scan was found to be significantly correlated to renogram function (correlation coefficient of 0.48, p < 0.001). Lastly, renal PW can be measured in a retrospective manner on existing CT scans with or without contrast.…”

“…Lastly, renal PW can be measured in a retrospective manner on existing CT scans with or without contrast. In addition, it does not need complex calculations or specific software for reconstruction [14]. Altogether, it can be reasoned that measuring PW on CT scans might be a simple and practical mean for studying selective renal function with ureteral stent.…”

Virtual Surgical Planning: A Novel Aid to Robot-Assisted Laparoscopic Partial Nephrectomy

“…It would be interesting to see if this technology can help better predict postoperative renal function after tumor resection because CT imaging alone has previously been correlated to renal function. 19 A valuable aspect of this technology in addition to its anatomic information is the renal functional information that it could potentially provide. Each VSP case provides the surgeon with an estimate of the renal functional surface area preoperatively.…”