Assessment of rapid changes in renal blood flow with (191m)Ir, an ultra-short-lived radionuclide.
We investigated the feasibility of using (191m)Ir (half-life, 5 s) to measure rapid dynamic alterations in differential renal blood flow.


METHODS
A nonobstructive constant renal pelvic pressure model was used. The renal pelves of 6 New Zealand White rabbits were drained by use of bilateral catheters, and increased hydrostatic pressure was achieved by raising 1 catheter to 16, 25, 30, or 35 cm above the level of the renal pelvis. The contralateral kidney served as the control. (191m)Ir first-pass angiograms were obtained at baseline, after the induction of elevated pressure in the renal pelvis, and after the pressure was returned to normal. A minimum of 3 sequential angiograms were obtained at each point.


RESULTS
The differential blood flow values (mean +/- SD) were 47.5% +/- 7.3% at baseline, decreased to 42.3% +/- 2.6% when the renal pelvic pressure was elevated (P = 0.001), and returned to 51.1% +/- 4.0% after the pressure was returned to normal (P = 0.0017). There was no significant difference between baseline and postcompression values (P = 0.4807).


CONCLUSIONS
It is possible to use (191m)Ir first-pass angiography to evaluate rapid dynamic changes in differential renal blood flow in an experimental animal model.
Division of Nuclear Medicine, Department of Radiology, Children's Hospital Boston and Harvard Medical School, Boston, Massachusetts 02115, USA. ted.treves@tch.harvard.edu
S Ted
ST
Treves
Alan B
AB
Packard
Leo C T
LC
Fung
D000818:Animals; D005240:Feasibility Studies; D007495:Iridium / Q000493:pharmacokinetics; D007554:Isotopes / Q000493:pharmacokinetics; D007668:Kidney / Q000098:blood supply* / Q000000981:diagnostic imaging* / Q000378:metabolism; D011866:Radioisotope Renography / Q000379:methods*; D019275:Radiopharmaceuticals / Q000378:metabolism; D051381:Rats; D012079:Renal Circulation / Q000502:physiology*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D007554:Isotopes; D019275:Radiopharmaceuticals; D007495:Iridium