FRACTIONAL MEAN TRANSIT-TIME IN TRANSPLANTED KIDNEYS STUDIED BY TECHNETIUM-99M-DTPA - COMPARISON OF CLINICAL AND BIOPSY FINDINGS

To determine the usefulness of fractional mean transit time ((MTT) in the differential diagnosis of postrenal transplant complications, Tc-9 9m-DTPA was used to evaluate differences in MTT between the outer zone (cortical nephron) and middle zone (juxtamedullary nephron, calcyces and cortical nephron) of the kidney. it is well known that acute rejec tion is characterized by delayed cortical transit time, whereas cortic al nephron function is well maintained and juxtamedullary function is impaired after renal ischemia. Methods: Technetium-99m-DTPA fractional MTT was determined by deconvolution analysis of 89 renograms obtained within 5 days of the date of kidney graft biopsy and evaluation. Resu lts: Outer zone MTT was significantly shorter than middle zone MTT in normals (2.7 +/- 0.4 versus 3.0 +/- 0.6 min, n = 22, p < 0.001), acute tubular necrosis (3.4 +/- 1.1 versus 3.6 +/- 1.4 min, n = 19, p < 0.0 1), chronic rejection (3.9 +/- 1.5 versus 5.0 +/- 2.3 min, n = 14, p < 0.001) and obstruction (4.1 +/- 0.6 versus 8.9 +/- 3.4 min, n = 13, p ( 0.001). in contrast, outer zone MTT was significantly longer than m iddle zone MTT in acute rejection (4.8 +/- 3.2 versus 4.2 +/- 2.5 min, n = 21, p < 0.05). Conclusion: Fractional MTT was demonstrated to be useful in differentiating acute rejection and ATN in transplanted kidn eys.