HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Alpert, N. M. Articles by Fischman, A. J. Search for Related Content PubMed PubMed Citation Articles by Alpert, N. M. Articles by Fischman, A. J.

Mapping of Local Renal Blood Flow with PET and H₂¹⁵O

¹ Division of Nuclear Medicine, Department of Radiology, Massachusetts General Hospital, Boston, Massachusetts
² Pfizer Global Research and Development, Groton, Connecticut
³ The Trauma Service, Massachusetts General Hospital, Boston, Massachusetts
⁴ Shriners Burns Institute, Harvard Medical School, Boston, Massachusetts
⁵ Departments of Radiology, Medicine, and Surgery, Harvard Medical School, Boston, Massachusetts
⁶ Renal Unit of the Medical Service, Massachusetts General Hospital, Boston, Massachusetts
⁷ Center of Experimental Pharmacology and Therapeutics, Harvard-MIT Division of Health Sciences and Technology, Boston, Massachusetts

We developed a noninvasive method for the mapping of regional renal blood flow in humans using PET and H₂¹⁵O. Methods: Fifteen subjects participated in the study, 5 with normal renal function and 10 with renal disease. The protocol used a whole-body PET scanner, intravenous bolus injection of 1,110–1,850 MBq H₂¹⁵O and sequential imaging at 3 s per frame. ¹³¹I-Iodohippuran was used to independently assess effective renal plasma flow in each subject. Hippuran clearance and renal blood flow (RBF) were measured twice, before and after treatment with probenecid, to verify that RBF is not affected. Flow analysis was based on the Kety model, according to the operational equation: C(t) = F C_a(u)du - k C(u)du, where F is the RBF, k is the tissue-to-blood clearance rate, C is the PET concentration, and C_a is the tracer concentration in the abdominal aorta. F and k were estimated by linear least squares on a pixel-by-pixel basis to produce quantitative maps (parametric images) of RBF. The flow maps were analyzed by regions of interest (largely excluding the medulla and collecting system) for each kidney on each slice and pooled to yield mean RBF. Results: In the 5 healthy subjects, mean RBF was 3.4 ± 0.4 mL/min/g. There was no difference in flow between kidneys (t = -0.59; n = 11; P > 0.95). Before treatment with probenecid, RBF was linearly related to hippuran clearance (r² = 0.92). Probenecid treatment significantly reduced hippuran clearance (P < 0.003), but RBF was unchanged (P > 0.17). Compared with healthy control subjects, RBF was significantly decreased in patients with renal disease (P < 0.002). Flow maps were of good quality in all subjects, exhibiting characteristic patterns, with higher values in regions composed largely of renal cortex. Conclusion: Parametric mapping of RBF with PET and H₂¹⁵O provides a straightforward, noninvasive method for quantitative mapping of RBF, which may prove useful in research applications and in the management of patients whose therapy alters renal tubular transport.

Key Words: renal blood flow • parametric imaging • H₂¹⁵O