ACUTE REJECTION

            Male 47 year old,  underwent bank  kidney transplantation 1 week ago. Diuresis dropped significantly. Renogram performed with 99m Tc-DTPA. Kidney in left inferior abdominal quadrant with increased size and diminished perfusion (upper 2 rows, first 8 seconds). Bottom, 4 images 1 min frame duration Those at left are from first and 2nd min and the ones at right from 29th and 30st min. Note  less than normal uptake, increased blood pool activity and little excretion into the bladder, consistent with function involvement.

            This pattern is suggestive of acute rejection. When sequential studies show a progressive decrease in perfusion and excretion of the kidney,  then the probability of rejection is higher (1).

            Barba et al concluded that "The presence of alterations in the vascular stage and in the parenchymal stage of the renal gammagraphy immediately after the transplant are variables that affect the survival of the graft." (2).

            Both DTPA or MAG-3, labeled with 99m Tc can be used, giving better images the latter, though the cost of the tracer is greater. There might be some differences in the performance of these agents (3).

            In the acute stage is better the yield of 99m Tc MAG-3, especially in the differential diagnosis of acute tubular necrosis and other conditions as rejection.

References:

1   Etchebere, Elba, Ramos Celso Dario y Camargo, Edwaldo. Trasplante Renal.p: 425-433 en: Medicina Nuclear Aplicaciones Clínicas. Eds: I. Carrio - P. González. Editorial Masson, Barcelona España, 2003.

2   Barba JF, Romero L, Tolosa E, Algarra R, Rosell D, Robles JE, Zudaire JJ, Berian  JM, Richter JA, Pascual JI. Study on the findings of an immediate renal gammagraphy and its effect on the survival of a kidney graft. Actas Urol Esp. 2011 Apr;35(4):218-24. Epub 2011 Mar 21.

3   Aktaş A, Aras M, Colak T, Gençoğlu A, Karakayali H. Comparison of Tc-99m DTPA and Tc-99m MAG3 perfusion time-activity curves in patients with renal allograft dysfunction.Transplant Proc. 2006 Mar;38(2):449-53.
 

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