Can severely impaired cortical transit predict which children with pelvi-ureteric junction stenosis detected antenatally might benefit from pyeloplasty?

Abstract

Severely impaired cortical transit seems to be a valuable marker of those patients who could benefit from a pyeloplasty, either because of the high probability of postoperative DRF improvement, or because of DRF deterioration in case of an conservative approach. However, a normal cortical transit, as defined in this study, does not exclude the risk of DRF deterioration. Alternatively, the design of this study does not allow excluding the fact that DRF might improve after pyeloplasty despite a normal cortical transit.

Comparison of two different periods of renal cortical activity ratios in the evaluation of ureteropelvic junction obstruction by dynamic renal scintigraphy

“…Transit time in nonobstructive patients with dilatation is longer when compared to normal patients [8,22]. Studies carried out in recent years show that the evaluation of both prolonged cortical transit time and poor kidney washout is a valuable indicator/marker for patients who can benefit from pyeloplasty [4,29]. Also in our study, the activity remaining in the kidneys in 20th minute was found over 82.8% and 74.2% for Tc99m DTPA and Tc99m MAG-3 respectively and this supports the existence of obstruction.…”

SNMMI Procedure Standard/EANM Practice Guideline for Diuretic Renal Scintigraphy in Adults With Suspected Upper Urinary Tract Obstruction 1.0

“…74,75 A prolonged parenchymal transit time is not specific to obstruction but increases the likelihood of its presence. The parenchymal transit time calculation is not offered on many commercial systems but can be implemented by following the recommendations in a previously published consensus report.…”

“…3,35,38,57,63,75 Drainage can be quantitated by measuring the residual post-furosemide or postvoid renal counts normalized to the maximum counts. 57,63 As an example, assume the time to peak is 10 minutes and there is still retention in the collecting system after furosemide administration, with a T 1 / 2 of 18 minutes; the patient voids after the study and the postvoid/max count ratio at 30 minutes is 0.10.…”

“…74,75 Tissue tracer transit provides a simple method to assess the parenchymal transit time by visually inspecting the transit of 99m Tc-MAG3 from the renal parenchyma to the renal pelvis. 87,88 A delayed tissue tracer transit is defined visually by a photopenic renal pelvis that is present at the second or third minute after injection, persists through the eighth to tenth minutes, and is accompanied by a stable or increasing parenchymal concentration.…”

Nuclear Medicine in Pediatric Urology

“…As mentioned earlier, along with its favorable dosi metry, because of its higher clearance (40%) than that of 99m Tc-DTPA, 99m Tc-MAG3 provides superior diagnostic images and is an agent of choice for the renal scintigraphy in neonates and children. Since future deterioration of renal function cannot be predicted solely based on findings such as sonographically progressive dilation, obstruction, low differential function on diuretic scan 20) , cortical transit A B time is expected to be a reliable predictive marker 21) , and among many technical attempts to evaluate it, visual estimation of cortical transit seems to be the best approach 22) . Serial renal scintigraphy may help physicians in followingup of patients after therapeutic intervention.…”